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  • 1951.
    Kim, Eun Jeong
    et al.
    Univ St Andrews, Sch Chem, St Andrews KY16 9ST, Fife, Scotland;ALISTORE ERI, F-80039 Amiens, France.
    Ma, Le Anh
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Duda, Laurent
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Pickup, David M.
    Univ Kent, Sch Phys Sci, Canterbury CT2 7NH, Kent, England.
    Chadwick, Alan V.
    Univ Kent, Sch Phys Sci, Canterbury CT2 7NH, Kent, England.
    Younesi, Reza
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry. ALISTORE ERI, F-80039 Amiens, France.
    Irvine, John T. S.
    Univ St Andrews, Sch Chem, St Andrews KY16 9ST, Fife, Scotland.
    Armstrong, A. Robert
    Univ St Andrews, Sch Chem, St Andrews KY16 9ST, Fife, Scotland;ALISTORE ERI, F-80039 Amiens, France.
    Oxygen Redox Activity through a Reductive Coupling Mechanism in the P3-Type Nickel-Doped Sodium Manganese Oxide2020In: ACS Applied Energy Materials, E-ISSN 2574-0962, Vol. 3, no 1, p. 184-191Article in journal (Refereed)
    Abstract [en]

    Increasing dependence on rechargeable batteries for energy storage calls for the improvement of energy density of batteries. Toward this goal, introduction of positive electrode materials with high voltage and/or high capacity is in high demand. The use of oxygen chemistry in lithium and sodium layered oxides has been of interest to achieve high capacity. Nevertheless, a complete understanding of oxygen-based redox processes remains elusive especially in sodium ion batteries. Herein, a novel P3-type Na0.67Ni0.2Mn0.8O2, synthesized at low temperature, exhibits oxygen redox activity in high potentials. Characterization using a range of spectroscopic techniques reveals the anionic redox activity is stabilized by the reduction of Ni, because of the strong Ni 3d-O 2p hybridization states created during charge. This observation suggests that different route of oxygen redox processes occur in P3 structure materials, which can lead to the exploration of oxygen redox chemistry for further development in rechargeable batteries.

  • 1952.
    Kim, Eun Jeong
    et al.
    Univ St Andrews, Sch Chem, St Andrews KY16 9ST, Fife, Scotland.;ALISTORE ERI, F-80039 Amiens, France.;Quad One, Faraday Inst, Harwell Sci & Innovat Campus, Didcot OX11 0RA, Oxon, England..
    Ma, Le Anh
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Pickup, David M.
    Univ Kent, Sch Phys Sci, Canterbury CT2 7NH, Kent, England..
    Chadwick, Alan, V
    Univ Kent, Sch Phys Sci, Canterbury CT2 7NH, Kent, England..
    Younesi, Reza
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry. Univ Kent, Sch Phys Sci, Canterbury CT2 7NH, Kent, England..
    Maughan, Philip
    Univ St Andrews, Sch Chem, St Andrews KY16 9ST, Fife, Scotland.;Quad One, Faraday Inst, Harwell Sci & Innovat Campus, Didcot OX11 0RA, Oxon, England..
    Irvine, John T. S.
    Univ St Andrews, Sch Chem, St Andrews KY16 9ST, Fife, Scotland.;Quad One, Faraday Inst, Harwell Sci & Innovat Campus, Didcot OX11 0RA, Oxon, England..
    Armstrong, A. Robert
    Univ St Andrews, Sch Chem, St Andrews KY16 9ST, Fife, Scotland.;ALISTORE ERI, F-80039 Amiens, France.;Quad One, Faraday Inst, Harwell Sci & Innovat Campus, Didcot OX11 0RA, Oxon, England..
    Vacancy-Enhanced Oxygen Redox Reversibility in P3-Type Magnesium-Doped Sodium Manganese Oxide Na0.67Mg0.2Mn0.8O22020In: ACS Applied Energy Materials, E-ISSN 2574-0962, Vol. 3, no 11, p. 10423-10434Article in journal (Refereed)
    Abstract [en]

    Lithium-rich layered oxides and sodium layered oxides represent attractive positive electrode materials exhibiting excess capacity delivered by additional oxygen redox activity. However, structural degradation in the bulk and detrimental reactions with the electrolyte on the surface often occur, leading to limited reversibility of oxygen redox processes. Here, we present the properties of P3-type Na0.67Mg0.2Mn0.8O2 synthesized under both air and oxygen. Both materials exhibit stable cycling performance in the voltage range of 1.8-3.8 V, where the Mn3+/Mn4+ redox couple entirely dominates the electrochemical reaction. Oxygen redox activity is triggered for both compounds in the wider voltage window 1.8-4.3 V with typical large voltage hysteresis from nonbonding O 2p states generated by substituted Mg. Interestingly, for the compound prepared under oxygen, an additional novel reversible oxygen redox activity is shown with an exceptionally small voltage hysteresis (20 mV). The presence of vacancies in the transition-metal layers is shown to play a critical role not only in forming unpaired O 2p states independent of substituted elements but also in stabilizing the P3 structure during charge with reduced structural transformation to the O'3 phase at the end of discharge. This study reveals the important role of vacancies in P3-type sodium layered oxides to increase energy density using both cationic and anionic redox processes.

  • 1953.
    Kim, Eun Jeong
    et al.
    Univ St Andrews, Sch Chem, St Andrews KY16 9ST, Fife, Scotland.;Faraday Inst Quad One, Harwell Sci & Innovat Campus, Didcot OX11 0RA, Oxon, England.;ALISTORE ERI, F-80039 Amiens, France..
    Maughan, Philip A.
    Univ St Andrews, Sch Chem, St Andrews KY16 9ST, Fife, Scotland.;Faraday Inst Quad One, Harwell Sci & Innovat Campus, Didcot OX11 0RA, Oxon, England..
    Bassey, Euan N.
    Univ Cambridge, Dept Chem, Lensfield Rd, Cambridge CB2 1EW, England..
    Clement, Raphaele J.
    Univ Calif Santa Barbara, Dept Mat, Santa Barbara, CA 93106 USA.;Univ Calif Santa Barbara, Mat Res Lab, Santa Barbara, CA 93106 USA..
    Ma, Le Anh
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Duda, Laurent
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Condensed Matter Physics of Energy Materials.
    Sehrawat, Divya
    UNSW Australia, Sch Chem, Sydney, NSW 2052, Australia..
    Younesi, Reza
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry. ALISTORE ERI, F-80039 Amiens, France..
    Sharma, Neeraj
    UNSW Australia, Sch Chem, Sydney, NSW 2052, Australia..
    Grey, Clare P.
    Faraday Inst Quad One, Harwell Sci & Innovat Campus, Didcot OX11 0RA, Oxon, England.;ALISTORE ERI, F-80039 Amiens, France.;Univ Cambridge, Dept Chem, Lensfield Rd, Cambridge CB2 1EW, England..
    Armstrong, A. Robert
    Univ St Andrews, Sch Chem, St Andrews KY16 9ST, Fife, Scotland.;Faraday Inst Quad One, Harwell Sci & Innovat Campus, Didcot OX11 0RA, Oxon, England.;ALISTORE ERI, F-80039 Amiens, France..
    Importance of Superstructure in Stabilizing Oxygen Redox in P3-Na0.67Li0.2Mn0.8O22022In: Advanced Energy Materials, ISSN 1614-6832, E-ISSN 1614-6840, Vol. 12, no 3, article id 2102325Article in journal (Refereed)
    Abstract [en]

    Activation of oxygen redox represents a promising strategy to enhance the energy density of positive electrode materials in both lithium and sodium-ion batteries. However, the large voltage hysteresis associated with oxidation of oxygen anions during the first charge represents a significant challenge. Here, P3-type Na0.67Li0.2Mn0.8O2 is reinvestigated and a ribbon superlattice is identified for the first time in P3-type materials. The ribbon superstructure is maintained over cycling with very minor unit cell volume changes in the bulk while Li ions migrate reversibly between the transition metal and Na layers at the atomic scale. In addition, a range of spectroscopic techniques reveal that a strongly hybridized Mn 3d-O 2p favors ligand-to-metal charge transfer, also described as a reductive coupling mechanism, to stabilize reversible oxygen redox. By preparing materials under three different synthetic conditions, the degree of ordering between Li and Mn is varied. The sample with the maximum cation ordering delivers the largest capacity regardless of the voltage windows applied. These findings highlight the importance of cationic ordering in the transition metal layers, which can be tuned by synthetic control to enhance anionic redox and hence energy density in rechargeable batteries.

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  • 1954.
    Kim, Hee Jae
    et al.
    Sejong Univ, Hybrid Mat Res Ctr, Dept Nanotechnol & Adv Mat Engn, Seoul 05006, South Korea.;Sejong Univ, Sejong Battery Inst, Seoul 05006, South Korea..
    Umirov, Nurzhan
    Chungnam Natl Univ, Grad Sch Energy Sci & Technol, 99 Daehak Ro,Yuseong Gu, Daejeon 34134, South Korea..
    Park, Jae-Sang
    Sejong Univ, Hybrid Mat Res Ctr, Dept Nanotechnol & Adv Mat Engn, Seoul 05006, South Korea.;Sejong Univ, Sejong Battery Inst, Seoul 05006, South Korea..
    Lim, Jae-Hong
    Pohang Accelerator Lab, 80 Jigokro-127-Beongil,Nam Gu, Pohang 37673, Gyeongbuk, South Korea..
    Zhu, Jiefang
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Kim, Sung-Soo
    Chungnam Natl Univ, Grad Sch Energy Sci & Technol, 99 Daehak Ro,Yuseong Gu, Daejeon 34134, South Korea..
    Myung, Seung-Taek
    Sejong Univ, Hybrid Mat Res Ctr, Dept Nanotechnol & Adv Mat Engn, Seoul 05006, South Korea.;Sejong Univ, Sejong Battery Inst, Seoul 05006, South Korea..
    Lithium dendritic growth inhibitor enabling high capacity, dendrite-free, and high current operation for rechargeable lithium batteries2022In: Energy Storage Materials, ISSN 2405-8289, E-ISSN 2405-8297, Vol. 46, p. 76-89Article in journal (Refereed)
    Abstract [en]

    There is no doubt that lithium-metal batteries (LMBs) are considered as attractive power sources owing to their ex-traordinarily high energy density. However, the formation of lithium dendrites during repeated plating/stripping processes hinders their practical application. Herein, we introduce phosphorous pentoxide (P2O5) as an addi-tive to commercial carbonate-based electrolytes to effectively suppress the dendritic growth on the surface of a lithium-metal anode. Significant improvement of the lifespan and coulombic efficiency of the cell were observed with the addition of P2O5 to the electrolyte in Li || Li, Li || Type 316L SS, Li || Cu, and Li || graphite cells. According to surface analyses and microscopic studies, we found reduction mechanism of the P2O5-induced solid-electrolyte interphase (SEI) formation on Li metal. Namely, electrolytic decomposition product, LiF, reacts with P2O5 addi-tive in electrolyte, so that LiPO2F2 is produced by following reaction: 6LiF + 2P(2)O(5) ->& nbsp;3LiPO(2)F(2) + Li3PO4, of which those products suppress dendritic growth of lithium as visualized by operando Synchrotron tomography. The compatibility and outstanding rate performance of the additive-based electrolyte were also demonstrated in Li || NCM full cells. As a result, this finding confirms an effective way to stabilize SEI layers in LMBs via a facile and inexpensive route.

  • 1955.
    Kim, Hyeyun
    et al.
    KTH Royal Inst Technol, Dept Chem Engn, SE-10044 Stockholm, Sweden.;Royal Inst Technol, Wallenberg Wood Sci Ctr, SE-10044 Stockholm, Sweden..
    Mattinen, Ulriika
    KTH Royal Inst Technol, Dept Chem Engn, SE-10044 Stockholm, Sweden..
    Guccini, Valentina
    Aalto Univ, Dept Bioprod & Biosyst, Sch Chem Engn, Aalto 00076, Finland..
    Liu, Haidong
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Salazar-Alvarez, German
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Lindstrom, Rakel Wreland
    KTH Royal Inst Technol, Dept Chem Engn, SE-10044 Stockholm, Sweden..
    Lindbergh, Goran
    KTH Royal Inst Technol, Dept Chem Engn, SE-10044 Stockholm, Sweden..
    Cornell, Ann
    KTH Royal Inst Technol, Dept Chem Engn, SE-10044 Stockholm, Sweden..
    Feasibility of Chemically Modified Cellulose Nanofiber Membranes as Lithium-Ion Battery Separators2020In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 12, no 37, p. 41211-41222Article in journal (Refereed)
    Abstract [en]

    Chemical modification of cellulose is beneficial to produce highly porous lithium-ion battery (LIB) separators, but introduction of high charge density adversely affects its electrochemical stability in a LiNi1/3Mn1/3Co1/3O2 (NMC)/graphite full cell. In this study, the influence of carboxylate functional groups in 2,2,6,6-tetramethylpiperidine-1-oxyl-mediated oxidized cellulose nanofibers (TOCNs) on the electrochemical performances of the LIB separator was investigated. X-ray photoelectron spectroscopy and in operando mass spectrometry measurements were used to elucidate the cause of failure of the batteries containing TOCN separators in the presence and absence of sodium counterions in the carboxylate groups and additives. For the TOCN separator with sodium carboxylate functional groups, it seems that Na deposition is the dominant reason for poor electrochemical stability of the cell thereof. The poor performance of the protonated TOCN separator, attributed to a high amount of gas evolution, is dramatically improved by adding 2 wt % of vinylene carbonate (VC) because of suppressed gas evolution. Unveiling the failure mechanism of the TOCN separators and successively implementing the strategies to improve performance, for example, removing Na, adding VC, and adjusting cycling rates, enable a remarkable cycling performance in the NMC/graphite full cell at approximate to 2 C (3 mA/cm(2)) of a fast discharging rate. Despite the aforementioned efforts and compromises required, an increased charge density of the TOCN is beneficial to acquire a mechanically stronger separator. In conclusion, the manufacturing process of cellulose nanofibers needs to be carefully adjusted to acquire a desired separator property. To the best of our knowledge, it is first reported to perform operando gas evolution measurements to systematically investigate the electrochemical stability of nanocellulose as an LIB separator material. The results elucidate not only the challenges for extensive applications of hygroscopic biomaterials for commercial LIBs but also the practical solutions to achieve high electrochemical stability of the materials.

  • 1956.
    Kim, Hyeyun
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Mattinen, Ulriika
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Guccini, Valentina
    Aalto Univ, Dept Bioprod & Biosyst, Sch Chem Engn, Aalto 00076, Finland..
    Liu, Haidong
    Uppsala Univ, Dept Chem, Angstrom Lab, SE-75121 Uppsala, Sweden..
    Salazar-Alvarez, German
    Uppsala Univ, Dept Mat Sci & Engn, Angstrom Lab, SE-75121 Uppsala, Sweden..
    Lindström, Rakel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Cornell, Ann M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Feasibility of Chemically Modified Cellulose Nanofiber Membranes as Lithium-Ion Battery Separators2020In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 12, no 37, p. 41211-41222Article in journal (Refereed)
    Abstract [en]

    Chemical modification of cellulose is beneficial to produce highly porous lithium-ion battery (LIB) separators, but introduction of high charge density adversely affects its electrochemical stability in a LiNi1/3Mn1/3Co1/3O2 (NMC)/graphite full cell. In this study, the influence of carboxylate functional groups in 2,2,6,6-tetramethylpiperidine-1-oxyl-mediated oxidized cellulose nanofibers (TOCNs) on the electrochemical performances of the LIB separator was investigated. X-ray photoelectron spectroscopy and in operando mass spectrometry measurements were used to elucidate the cause of failure of the batteries containing TOCN separators in the presence and absence of sodium counterions in the carboxylate groups and additives. For the TOCN separator with sodium carboxylate functional groups, it seems that Na deposition is the dominant reason for poor electrochemical stability of the cell thereof. The poor performance of the protonated TOCN separator, attributed to a high amount of gas evolution, is dramatically improved by adding 2 wt % of vinylene carbonate (VC) because of suppressed gas evolution. Unveiling the failure mechanism of the TOCN separators and successively implementing the strategies to improve performance, for example, removing Na, adding VC, and adjusting cycling rates, enable a remarkable cycling performance in the NMC/graphite full cell at approximate to 2 C (3 mA/cm(2)) of a fast discharging rate. Despite the aforementioned efforts and compromises required, an increased charge density of the TOCN is beneficial to acquire a mechanically stronger separator. In conclusion, the manufacturing process of cellulose nanofibers needs to be carefully adjusted to acquire a desired separator property. To the best of our knowledge, it is first reported to perform operando gas evolution measurements to systematically investigate the electrochemical stability of nanocellulose as an LIB separator material. The results elucidate not only the challenges for extensive applications of hygroscopic biomaterials for commercial LIBs but also the practical solutions to achieve high electrochemical stability of the materials.

  • 1957.
    Kim, Jong Min
    et al.
    Seoul Natl Univ, Grad Sch Convergence Sci & Technol, 145 Gwanggyo Ro, Suwon 16229, Gyeonggi Do, South Korea.;Adv Inst Convergence Technol, 145 Gwanggyo Ro, Suwon 16229, Gyeonggi Do, South Korea..
    Cho, Youngseul
    Seoul Natl Univ, Grad Sch Convergence Sci & Technol, 145 Gwanggyo Ro, Suwon 16229, Gyeonggi Do, South Korea..
    Guccini, Valentina
    Aalto Univ, Dept Bioprod & Biosyst, Otakaari 5A, Helsinki 02150, Finland..
    Hahn, Misun
    Seoul Natl Univ, Grad Sch Convergence Sci & Technol, 145 Gwanggyo Ro, Suwon 16229, Gyeonggi Do, South Korea..
    Yan, Bingyi
    Seoul Natl Univ, Grad Sch Convergence Sci & Technol, 145 Gwanggyo Ro, Suwon 16229, Gyeonggi Do, South Korea..
    Salazar-Alvarez, German
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solid State Physics.
    Piao, Yuanzhe
    Seoul Natl Univ, Grad Sch Convergence Sci & Technol, 145 Gwanggyo Ro, Suwon 16229, Gyeonggi Do, South Korea.;Adv Inst Convergence Technol, 145 Gwanggyo Ro, Suwon 16229, Gyeonggi Do, South Korea..
    TEMPO-oxidized cellulose nanofibers as versatile additives for highly stable silicon anode in lithium-ion batteries2021In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 369, article id 137708Article in journal (Refereed)
    Abstract [en]

    Silicon (Si) has been considered the most promising anode material for next-generation lithium-ion batteries due to its high theoretical capacity and natural abundance. However, the Si anode suffers from massive volume change, which results in challenging cycling performance. Many researches demonstrated that polymeric binder plays an important role to sustain the structural integrity of Si anodes. While most studies about the binder material have been focused on enhancing distinctive properties such as adhesive strength and mechanical property, it has been recently shown that binder distribution can help to improve electrochemical performance. Herein, we introduce TEMPO-oxidized cellulose nanofiber (TOCNF) as a versatile additive for the binder of silicon anode. The one-dimensional morphology of TOCNF efficiently reinforces the mechanical properties of the electrode. The TOCNF additive also contains carboxylic groups with sufficient flexibility to induce intimate interaction with Si via hydrogen bonding. Based on all of these beneficial features of TOCNF, the addition of similar to 1 wt% of TOCNF of the whole weight of silicon anode slurry significantly improved cycling stability. With pre-mixing, the resulting Si-TOCNF allows efficient water-based binder solution penetration, thus improving uniform binder distribution of electrode. Furthermore, the well-distributed binder protects silicon surface and forms a stable SEI layer. The current study suggests that the TOCNF additive facilitates uniform binder distribution in the electrode with enhanced mechanical properties, leading to improved cycling performance. (C) 2021 Elsevier Ltd. All rights reserved.

  • 1958.
    Kim, Kyung Ho
    et al.
    Chalmers Univ Technol, Dept Microtechnol & Nanosci, SE-41296 Gothenburg, Sweden..
    He, Hans
    Chalmers Univ Technol, Dept Microtechnol & Nanosci, SE-41296 Gothenburg, Sweden..
    Rodner, Marius
    Linköping Univ, Dept Phys Chem & Biol, S-58183 Linköping, Sweden..
    Yakimova, Rositsa
    Linköping Univ, Dept Phys Chem & Biol, S-58183 Linköping, Sweden..
    Larsson, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Piantek, Marten
    Univ Zaragoza, Inst Nanociencia Aragon, Zaragoza 50018, Spain.;Univ Zaragoza, Lab Microscopias Avanzadas, Zaragoza 50018, Spain.;Univ Zaragoza, Dept Fis Mat Condensada, E-50009 Zaragoza, Spain..
    Serrate, David
    Univ Zaragoza, Dept Fis Mat Condensada, E-50009 Zaragoza, Spain.;Univ Zaragoza, Inst Ciencia Mat Aragon, CSIC, E-50009 Zaragoza, Spain..
    Zakharov, Alexei
    Max IV Lab, S-22100 Lund, Sweden..
    Kubatkin, Sergey
    Chalmers Univ Technol, Dept Microtechnol & Nanosci, SE-41296 Gothenburg, Sweden..
    Eriksson, Jens
    Linköping Univ, Dept Phys Chem & Biol, S-58183 Linköping, Sweden..
    Lara-Avila, Samuel
    Chalmers Univ Technol, Dept Microtechnol & Nanosci, SE-41296 Gothenburg, Sweden.;Natl Phys Lab, Hampton Rd, Teddington TW11 0LW, Middx, England..
    Chemical Sensing with Atomically Thin Platinum Templated by a 2D Insulator2020In: Advanced Materials Interfaces, ISSN 2196-7350, Vol. 7, no 12, article id 1902104Article in journal (Refereed)
    Abstract [en]

    Boosting the sensitivity of solid-state gas sensors by incorporating nanostructured materials as the active sensing element can be complicated by interfacial effects. Interfaces at nanoparticles, grains, or contacts may result in nonlinear current-voltage response, high electrical resistance, and ultimately, electric noise that limits the sensor read-out. This work reports the possibility to prepare nominally one atom thin, electrically continuous platinum layers by physical vapor deposition on the carbon zero layer (also known as the buffer layer) grown epitaxially on silicon carbide. With a 3-4 angstrom thin Pt layer, the electrical conductivity of the metal is strongly modulated when interacting with chemical analytes, due to charges being transferred to/from Pt. The strong interaction with chemical species, together with the scalability of the material, enables the fabrication of chemiresistor devices for electrical read-out of chemical species with sub part-per-billion (ppb) detection limits. The 2D system formed by atomically thin Pt on the carbon zero layer on SiC opens up a route for resilient and high sensitivity chemical detection, and can be the path for designing new heterogenous catalysts with superior activity and selectivity.

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  • 1959.
    Kim, Min-Jeong
    et al.
    Chung Ang Univ, Dept Phys, Seoul 06974, South Korea.;Chung Ang Univ, Ctr Berry Curvature based New Phenomena, Seoul 06974, South Korea..
    Lee, Won-Yong
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics. Chung Ang Univ, Ctr Berry Curvature based New Phenomena, Seoul 06974, South Korea..
    Kang, Min-Sung
    Chung Ang Univ, Dept Phys, Seoul 06974, South Korea.;Chung Ang Univ, Ctr Berry Curvature based New Phenomena, Seoul 06974, South Korea..
    Kim, Si-Hoo
    Chung Ang Univ, Dept Phys, Seoul 06974, South Korea.;Chung Ang Univ, Ctr Berry Curvature based New Phenomena, Seoul 06974, South Korea..
    Cho, Jung-Min
    Chung Ang Univ, Dept Phys, Seoul 06974, South Korea.;Chung Ang Univ, Ctr Berry Curvature based New Phenomena, Seoul 06974, South Korea..
    Kim, Yun-Ho
    Chung Ang Univ, Dept Phys, Seoul 06974, South Korea.;Chung Ang Univ, Ctr Berry Curvature based New Phenomena, Seoul 06974, South Korea..
    Choi, Jae-Won
    Chung Ang Univ, Dept Phys, Seoul 06974, South Korea.;Chung Ang Univ, Ctr Berry Curvature based New Phenomena, Seoul 06974, South Korea..
    Park, No-Won
    Chung Ang Univ, Dept Phys, Seoul 06974, South Korea.;Chung Ang Univ, Ctr Berry Curvature based New Phenomena, Seoul 06974, South Korea..
    Kim, Gil-Sung
    Chung Ang Univ, Dept Phys, Seoul 06974, South Korea.;Chung Ang Univ, Ctr Berry Curvature based New Phenomena, Seoul 06974, South Korea..
    Yoon, Young-Gui
    Chung Ang Univ, Dept Phys, Seoul 06974, South Korea.;Chung Ang Univ, Ctr Berry Curvature based New Phenomena, Seoul 06974, South Korea..
    Lee, Sang-Kwon
    Chung Ang Univ, Dept Phys, Seoul 06974, South Korea.;Chung Ang Univ, Ctr Berry Curvature based New Phenomena, Seoul 06974, South Korea..
    Intrinsic Seebeck coefficients of 2D polycrystalline PtSe2 semiconducting films through two-step annealing2023In: Journal of Materials Chemistry A, ISSN 2050-7488, E-ISSN 2050-7496, Vol. 11, no 11, p. 5714-5724Article in journal (Refereed)
    Abstract [en]

    Because of the high contact resistance between a metal and a film, evaluating the intrinsic Seebeck coefficient of large-area two-dimensional (2D) semiconducting films with high-resistance is challenging. Here, we report a simple scheme to measure the large-area Seebeck coefficients of 2D polycrystalline platinum diselenide (PtSe2) thin films, whose electrical resistance (>2 M omega) is too high to measure the thermoelectric (TE) properties, by thermal annealing. As-prepared PtSe2 thin films deposited on sapphire substrates and treated by a two-step thermal annealing process at 574 K exhibited an intrinsic Seebeck coefficient > similar to 160 mu V K-1, which is 400% higher than that of the single-crystalline PtSe2 bulk, under a temperature gradient of up to 5 K along the samples. In addition, we confirm that the in-plane Seebeck coefficient of the two-step annealed samples was independent of the metal electrode. In addition, the role of thermal annealing in intrinsically-high-resistance 2D PtSe2 semiconducting films based on the atomic-scale crystallographic characteristics of these films and the measured contact resistance between the metal and PtSe2 layer is further discussed. Our finding represents an important achievement in understanding and measuring the Seebeck effect of high-TE-performance 2D layered transition metal dichalcogenide materials.

  • 1960.
    Kim, Minjin
    et al.
    Korea Inst Energy Res, Ulsan Adv Energy Technol R&D Ctr, Ulsan 44776, South Korea..
    Jeong, Jaeki
    Ecole Polytech Fed Lausanne EPFL, Lab Photon & Interfaces, Inst Chem Sci & Engn, CH-1015 Lausanne, Switzerland..
    Lu, Haizhou
    Ecole Polytech Fed Lausanne EPFL, Lab Photon & Interfaces, Inst Chem Sci & Engn, CH-1015 Lausanne, Switzerland..
    Lee, Tae Kyung
    Korea Inst Energy Res KIER, Photovolta Res Dept, Daejeon 34129, South Korea..
    Eickemeyer, Felix T.
    Ecole Polytech Fed Lausanne EPFL, Lab Photon & Interfaces, Inst Chem Sci & Engn, CH-1015 Lausanne, Switzerland..
    Liu, Yuhang
    Ecole Polytech Fed Lausanne EPFL, Lab Photon & Interfaces, Inst Chem Sci & Engn, CH-1015 Lausanne, Switzerland..
    Choi, In Woo
    Korea Inst Energy Res, Ulsan Adv Energy Technol R&D Ctr, Ulsan 44776, South Korea..
    Choi, Seung Ju
    Korea Inst Energy Res, Ulsan Adv Energy Technol R&D Ctr, Ulsan 44776, South Korea..
    Jo, Yimhyun
    Korea Inst Energy Res, Ulsan Adv Energy Technol R&D Ctr, Ulsan 44776, South Korea..
    Kim, Hak-Beom
    Korea Inst Energy Res, Ulsan Adv Energy Technol R&D Ctr, Ulsan 44776, South Korea..
    Mo, Sung-In
    Korea Inst Energy Res, Ulsan Adv Energy Technol R&D Ctr, Ulsan 44776, South Korea..
    Kim, Young-Ki
    Ulsan Natl Inst Sci & Technol UNIST, Cent Res Facil UCRF, Ulsan 44919, South Korea..
    Lee, Heunjeong
    Univ Ulsan, Dept Phys, Ulsan 44610, South Korea.;Univ Ulsan, Energy Harvest Storage Res Ctr, Ulsan 44610, South Korea..
    An, Na Gyeong
    Ulsan Natl Inst Sci & Technol UNIST, Sch Energy & Chem Engn, Dept Energy Engn, Ulsan 44919, South Korea..
    Cho, Shinuk
    Univ Ulsan, Dept Phys, Ulsan 44610, South Korea.;Univ Ulsan, Energy Harvest Storage Res Ctr, Ulsan 44610, South Korea..
    Tress, Wolfgang R.
    Zurich Univ Appl Sci, Inst Computat Phys, Novel Semicond Devices Grp, CH-8401 Winterthur, Switzerland..
    Zakeeruddin, Shaik M.
    Ecole Polytech Fed Lausanne EPFL, Lab Photon & Interfaces, Inst Chem Sci & Engn, CH-1015 Lausanne, Switzerland..
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Kim, Jin Young
    Ulsan Natl Inst Sci & Technol UNIST, Sch Energy & Chem Engn, Dept Energy Engn, Ulsan 44919, South Korea..
    Grätzel, Michael
    Ecole Polytech Fed Lausanne EPFL, Lab Photon & Interfaces, Inst Chem Sci & Engn, CH-1015 Lausanne, Switzerland..
    Kim, Dong Suk
    Korea Inst Energy Res, Ulsan Adv Energy Technol R&D Ctr, Ulsan 44776, South Korea..
    Conformal quantum dot-SnO2 layers as electron transporters for efficient perovskite solar cells2022In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 375, no 6578, p. 302-306Article in journal (Refereed)
    Abstract [en]

    Improvements to perovskite solar cells (PSCs) have focused on increasing their power conversion efficiency (PCE) and operational stability and maintaining high performance upon scale-up to module sizes. We report that replacing the commonly used mesoporous-titanium dioxide electron transport layer (ETL) with a thin layer of polyacrylic acid-stabilized tin(IV) oxide quantum dots (paa-QD-SnO2) on the compact-titanium dioxide enhanced light capture and largely suppressed nonradiative recombination at the ETL-perovskite interface. The use of paa-QD-SnO2 as electron-selective contact enabled PSCs (0.08 square centimeters) with a PCE of 25.7% (certified 25.4%) and high operational stability and facilitated the scale-up of the PSCs to larger areas. PCEs of 23.3, 21.7, and 20.6% were achieved for PSCs with active areas of 1, 20, and 64 square centimeters, respectively.

  • 1961.
    Kim, Nara
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Lienemann, Samuel
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Khan, Ziyauddin
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Medicine and Health Sciences.
    Greczynski, Grzegorz
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Rahmanudin, Aiman
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Vagin, Mikhail
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Ahmed, Fareed
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Petsagkourakis, Ioannis
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Edberg, Jesper
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Medicine and Health Sciences.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Tybrandt, Klas
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    An intrinsically stretchable symmetric organic battery based on plant-derived redox molecules2023In: Journal of Materials Chemistry A, ISSN 2050-7488, E-ISSN 2050-7496, Vol. 11, no 46, p. 25703-25714Article in journal (Refereed)
    Abstract [en]

    Intrinsically stretchable energy storage devices are essential for the powering of imperceptible wearable electronics. Organic batteries based on plant-derived redox-active molecules can offer critical advantages from a safety, sustainability, and economic perspective, but such batteries are not yet available in soft and stretchable form factors. Here we report an intrinsically stretchable organic battery made of elastomeric composite electrodes formulated with alizarin, a natural dye derived from the plant Rubia tinctorum, whose two quinone motifs enable its uses in both positive and negative electrodes. The quaternary biocomposite electrodes possess excellent electron-ion conduction/coupling and superior stretchability (>300%) owing to self-organized hierarchical morphology. In a full-cell configuration, its energy density of 3.8 mW h cm(-3) was preserved at 100% strain, and assembled modules on stretchy textiles and rubber gloves can power integrated LEDs during various deformations. This work paves the way for low-cost, eco-friendly, and deformable batteries for next generation wearable electronics.

  • 1962.
    Kim, Nara
    et al.
    Linköping university, Sweden.
    Lienemann, Samuel
    Linköping university, Sweden.
    Khan, Ziyauddin
    Linköping university, Sweden.
    Greczynski, Grzegorz
    Linköping university, Sweden.
    Rahmanudin, Aiman
    Linköping university, Sweden.
    Vagin, Mikhail
    Linköping university, Sweden.
    Ahmed, Fareed
    Linköping university, Sweden.
    Petsagkourakis, Ioannis
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware. Linköping university, Sweden.
    Edberg, Jesper
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Crispin, Xavier
    Linköping university, Sweden.
    Tybrandt, Klas
    Linköping university, Sweden.
    An intrinsically stretchable symmetric organic battery based on plant-derived redox molecules2023In: Journal of Materials Chemistry A, ISSN 2050-7488, E-ISSN 2050-7496, Vol. 11, no 46, p. 25703-25714Article in journal (Refereed)
    Abstract [en]

    Intrinsically stretchable energy storage devices are essential for the powering of imperceptible wearable electronics. Organic batteries based on plant-derived redox-active molecules can offer critical advantages from a safety, sustainability, and economic perspective, but such batteries are not yet available in soft and stretchable form factors. Here we report an intrinsically stretchable organic battery made of elastomeric composite electrodes formulated with alizarin, a natural dye derived from the plant Rubia tinctorum, whose two quinone motifs enable its uses in both positive and negative electrodes. The quaternary biocomposite electrodes possess excellent electron-ion conduction/coupling and superior stretchability (>300%) owing to self-organized hierarchical morphology. In a full-cell configuration, its energy density of 3.8 mW h cm−3 was preserved at 100% strain, and assembled modules on stretchy textiles and rubber gloves can power integrated LEDs during various deformations. This work paves the way for low-cost, eco-friendly, and deformable batteries for next generation wearable electronics. 

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  • 1963.
    Kim, Nara
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Lienemann, Samuel
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Petsagkourakis, Ioannis
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Mengistie, Desalegn
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering. Calif Polytech State Univ San Luis Obispo, CA 93407 USA.
    Kee, Seyoung
    Univ Auckland, New Zealand.
    Ederth, Thomas
    Linköping University, Department of Physics, Chemistry and Biology, Biophysics and bioengineering. Linköping University, Faculty of Science & Engineering.
    Gueskine, Viktor
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Leclere, Philippe
    Univ Mons, Belgium.
    Lazzaroni, Roberto
    Univ Mons, Belgium.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Tybrandt, Klas
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Elastic conducting polymer composites in thermoelectric modules2020In: Nature Communications, E-ISSN 2041-1723, Vol. 11, no 1Article in journal (Refereed)
    Abstract [en]

    The rapid growth of wearables has created a demand for lightweight, elastic and conformal energy harvesting and storage devices. The conducting polymer poly(3,4-ethylenedioxythiophene) has shown great promise for thermoelectric generators, however, the thick layers of pristine poly(3,4-ethylenedioxythiophene) required for effective energy harvesting are too hard and brittle for seamless integration into wearables. Poly(3,4-ethylenedioxythiophene)-elastomer composites have been developed to improve its mechanical properties, although so far without simultaneously achieving softness, high electrical conductivity, and stretchability. Here we report an aqueously processed poly(3,4-ethylenedioxythiophene)-polyurethane-ionic liquid composite, which combines high conductivity (>140Scm(-1)) with superior stretchability (>600%), elasticity, and low Youngs modulus (<7MPa). The outstanding performance of this organic nanocomposite is the result of favorable percolation networks on the nano- and micro-scale and the plasticizing effect of the ionic liquid. The elastic thermoelectric material is implemented in the first reported intrinsically stretchable organic thermoelectric module. Though deformable thermoelectric materials are desirable for integrating thermoelectric devices into wearable electronics, typical thermoelectric materials are too brittle for practical application. Here, the authors report a high-performance elastic composite for stretchable thermoelectric modules.

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  • 1964.
    Kim, Seohan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solid State Physics. Pusan Natl Univ, Mat Technol & Res, Busan 46241, South Korea..
    Montero, Jose
    Pusan Natl Univ, Mat Technol & Res, Busan 46241, South Korea..
    Choi, Young Joong
    Pusan Natl Univ, Dept Mat Sci & Engn, Busan 46241, South Korea..
    Yoon, Jang-Hee
    Korea Basic Sci Inst, Busan Ctr, Busan 46742, South Korea..
    Choi, Yunju
    Korea Basic Sci Inst, Busan Ctr, Busan 46742, South Korea..
    Song, Pung Keun
    Pusan Natl Univ, Dept Mat Sci & Engn, Busan 46241, South Korea..
    Österlund, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solid State Physics.
    Embedded nanopattern for selectively suppressed thermal conductivity and enhanced transparency in a transparent conducting oxide film2022In: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 103, no Part A, article id 107757Article in journal (Refereed)
    Abstract [en]

    Transparent conductive oxide (TCO) thin films are cornerstones in many optoelectronic applications including displays, photovoltaics and touchscreens. In these devices, thin films with simultaneous high optical transparency and electrical conductivity are needed. Ideally, heat generated during normal device operation must ideally be compensated for to achieve optimum functionality. One possible way to address the thermal management problem is adding thermoelectric (TE) properties to TCO films. However, improving TE properties while maintaining optimal electrical conductivity and optical transparency is challenging: thermal and electrical transport properties are deeply intertwined. Here, we demonstrate an approach allowing for independent optimization of optical transparency, electrical conductivity and thermal conductivity. An embedded nanopattern structure is filled with indium tin oxide (ITO) and sandwiched between two ITO layers. The resulting triplelayered structure exhibits reduced thermal conductivity and excellent electrical conductivity. This is made possible by electron channels in the embedded ITO nanopattern that electrically connect top and bottom layers, while at the same time limiting phonon-mediated heat conduction. The filling fraction and thickness of the nanopattern are adjusted to improve optical transmission, achieving transparency higher than bare ITO film. The result is a transparent TCO triple layer film with simultaneous high TCO and thermoelectric figures of merit.

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  • 1965.
    Kim, Seohan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solid State Physics. Pusan Natl Univ, Mat Technol Res Inst, Busan 46241, South Korea.;Uppsala Univ, Dept Engn Sci, Angstrom Lab, SE-75121 Uppsala, Sweden..
    Yoon, Janghee
    Korea Basic Sci Inst, Busan Ctr, Busan 46742, South Korea..
    Park, Sungmin
    Pusan Natl Univ, Dept Mat Sci & Engn, Busan 46241, South Korea..
    Bang, Joonho
    Sungkyunkwan Univ, Dept Energy Sci, Suwon 16419, South Korea..
    Song, Pungkeun
    Pusan Natl Univ, Dept Mat Sci & Engn, Busan 46241, South Korea..
    Hydrogen-driven surface amorphization of the transparent oxide semiconductor thin-films for photovoltaic applications2021In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 555, article id 149702Article in journal (Refereed)
    Abstract [en]

    Crystalline transparent conductive oxides are promising candidates as front electrodes in electronic devices due to the high electron mobility and good optical transparency in the visible region. However, the rough surface morphology resulting from the grain growth during the deposition and post-annealing process triggers severe drawbacks in their thin-film applications. Here, we demonstrate the hydrogen-driven surface amorphization of the crystalline In?Sn?O (c-ITO) thin film. By introducing hydrogen gas during the deposition process, the surface of the c-ITO thin film is selectively amorphized, allowing for the smooth surface morphology while preserving the advantages of the crystalline thin film. The progressive surface amorphization of c-ITO thin film offers the tunability of the work function, leading to the improved power conversion efficiency of the thin-film solar cell. Our work provides a facile method to realize the smooth surface morphology of the c-ITO thin films, which can be further utilized for a wide range of crystalline thin films for optoelectronic applications.

  • 1966.
    Kim, Seong-Min
    et al.
    Gwangju Inst Sci and Technol, South Korea.
    Kim, Chang-Hyun
    Gwangju Inst Sci and Technol, South Korea; Gwangju Inst Sci and Technol, South Korea; Gachon Univ, Peoples R China.
    Kim, Youngseok
    Gwangju Inst Sci and Technol, South Korea.
    Kim, Nara
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering. Gwangju Inst Sci and Technol, South Korea.
    Lee, Won-June
    Gwangju Inst Sci and Technol, South Korea.
    Lee, Eun-Hak
    Gwangju Inst Sci and Technol, South Korea.
    Kim, Dokyun
    Gwangju Inst Sci and Technol, South Korea.
    Park, Sungjun
    RIKEN, Japan.
    Lee, Kwanghee
    Gwangju Inst Sci and Technol, South Korea; Gwangju Inst Sci and Technol, South Korea; Gwangju Inst Sci and Technol, South Korea.
    Rivnay, Jonathan
    Northwestern Univ, IL 60208 USA.
    Yoon, Myung-Han
    Gwangju Inst Sci and Technol, South Korea.
    Influence of PEDOT:PSS crystallinity and composition on electrochemical transistor performance and long-term stability2018In: Nature Communications, E-ISSN 2041-1723, Vol. 9, article id 3858Article in journal (Refereed)
    Abstract [en]

    Owing to the mixed electron/hole and ion transport in the aqueous environment, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)-based organic electrochemical transistor has been regarded as one of the most promising device platforms for bioelectronics. Nonetheless, there exist very few in-depth studies on how intrinsic channel material properties affect their performance and long-term stability in aqueous environments. Herein, we investigated the correlation among film microstructural crystallinity/composition, device performance, and aqueous stability in poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) films. The highly organized anisotropic ordering in crystallized conducting polymer films led to remarkable device characteristics such as large transconductance (similar to 20 mS), extraordinary volumetric capacitance (113 F.cm(-3)), and unprecedentedly high [mu C*] value (similar to 490 F.cm(-1) V-1 s(-1)). Simultaneously, minimized poly(styrenesulfonate) residues in the crystallized film substantially afforded marginal film swelling and robust operational stability even after amp;gt;20-day water immersion, amp;gt;2000-time repeated on-off switching, or high-temperature/pressure sterilization. We expect that the present study will contribute to the development of long-term stable implantable bioelectronics for neural recording/stimulation.

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  • 1967.
    Kim, Shin
    et al.
    Korea Basic Sci Inst KBSI, Busan Ctr, Busan, South Korea..
    Jeong, Yesul
    Korea Basic Sci Inst KBSI, Busan Ctr, Busan, South Korea..
    Park, Min-Ouk
    Suntech Engn Co Ltd, Technol Res Inst, Daegu, South Korea..
    Jang, Yujin
    Korea Basic Sci Inst KBSI, Busan Ctr, Busan, South Korea..
    Bae, Jong-Seong
    Korea Basic Sci Inst KBSI, Busan Ctr, Busan, South Korea..
    Hong, Kyong-Soo
    Korea Basic Sci Inst KBSI, Busan Ctr, Busan, South Korea..
    Kim, Seohan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solid State Physics. Pusan Natl Univ, Mat Technol Res Inst, Busan, South Korea..
    Song, Pungkeun
    Pusan Natl Univ, Dept Mat Sci & Engn, Busan, South Korea..
    Yoon, Jang-Hee
    Korea Basic Sci Inst KBSI, Busan Ctr, Busan, South Korea..
    Development of boron doped diamond electrodes material for heavy metal ion sensor with high sensitivity and durability2023In: JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY, ISSN 2238-7854, Vol. 23, p. 1375-1385Article in journal (Refereed)
    Abstract [en]

    We report on the optimized substrate pretreatment and deposition process conditions for boron-doped diamond (BDD) electrodes fabricated by hot-filament chemical vapor deposition (HFCVD). The optimized BDD electrode with a doping concentration of 8000 ppm showed high accuracy and precision in detecting Cd(II), Pb(II), and Cu(II) ions. In addition, this demonstrates excellent selectivity against external metal ions under the optimized stripping voltammetry measurement conditions. The detection limits of the target ions of Cd(II), Pb(II), and Cu(II) were 0.55 (+/- 0.05), 0.43 (+/- 0.04), and 0.74 (+/- 0.06) mg/L (S/N = 3), respectively. In real samples spiked with 100 mg/L Cd(II), Pb(II), and Cu(II), both the accuracy and precision of the BDD electrode were within 5%; the interference with organic matter was also negligible. The excellent selectivity and long-term stability indicate that the BDD electrode developed in this study are potentially useful for online water environment monitoring systems.

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  • 1968.
    King, George A
    et al.
    CSIRO-DBCE.
    Norberg, Peter
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för byggnadskvalitet.
    A Methodology for Quantifying the Atmospheric Corrosion Performance of Fabricated Metal Products in Marine Environments2000In: Marine Corrosion in Tropical Environments, West Conshohocken, PA: American Society for Testing and Materials , 2000, p. 114-132Chapter in book (Refereed)
    Abstract [en]

    In Australia a long-term project is studying the marine atmospheric corrosion performance of several metals and alloys, and a range of generic classes of coatings and finishes (metallic and organic) on steel and aluminum. Specimens have been exposed for over nine years at three marine sites, both in the open and under a specially designed glass shelter which has greatly accelerated deterioration. The sheet product test pieces include a range of features designed to simulate the types of distress introduced during manufacture and building, and at which corrosion defects initially manifest. A methodology is described for the development of quantitative performance indices for these formed specimens. The general philosophy involves using the collected data to determine appropriate weighting to different types of defects on features, or to the relative contribution of different features to overall defect indices and in turn their relative contribution to a total performance index. A rigorous mathematical procedure was followed to calculate defect indices and total performance indices for all products. Some results for the two-year specimens are discussed.

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  • 1969.
    Kinschel, Dominik
    KTH, School of Chemical Science and Engineering (CHE).
    Stable Redox Systems for Dye-Sensitized Solar Cells2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Dye sensitized solar cells are a new type of solar cells which open a new market thanks to their unique properties, which are semi transparency and the fact that they can be produced in various colors.

    After improving two existing syntheses for industrial applications, this thesis takes the approach to develop new redox mediators for devices with an aim on improving stability. Five redox mediators with cobalt, copper and iron as metal center were synthesized and characterized by NMR spectroscopy, cyclic voltammetry and UV/VIS spectrophotometry. Three of them were selected for evaluation in test cells. Most promising results were obtained with a copper complex, using the tandem redox approach a new record efficiency of 7.7% for copper based electrolytes in dye-sensitized solar cells was obtained.

  • 1970.
    Kirnbauer, A.
    et al.
    TU Wien, Inst Mat Sci & Technol, A-1060 Vienna, Austria..
    Wagner, A.
    TU Wien, Inst Mat Sci & Technol, A-1060 Vienna, Austria..
    Moraes, V
    TU Wien, Inst Mat Sci & Technol, A-1060 Vienna, Austria..
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Hans, M.
    Rhein Westfal TH Aachen, Mat Chem, D-52074 Aachen, Germany..
    Schneider, J. M.
    Rhein Westfal TH Aachen, Mat Chem, D-52074 Aachen, Germany..
    Polcik, P.
    Plansee Composite Mat GmbH, D-86983 Lechbruck, Germany..
    Mayrhofer, P. H.
    TU Wien, Inst Mat Sci & Technol, A-1060 Vienna, Austria..
    Thermal stability and mechanical properties of sputtered (Hf,Ta,V,W,Zr)-diborides2020In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 200, p. 559-569Article in journal (Refereed)
    Abstract [en]

    Non-reactive magnetron sputtering of a diboride target composed of HfB2, TaB2, VB2, W2B5, and ZrB2 with equimolar composition leads to the formation of crystalline single-phase solid solution diboride thin films, (Hf,Ta,V,W,Zr)B2, with a high-entropy metal-sublattice. Their growth morphology (dense and fine- fibrous), crystal structure (AlB2-type), as well as mechanical properties (indentation modulus E of ~580 GPa and hardness H of ~45 GPa), and chemical compositions are basically independent of the substrate bias potential applied (varied between -40 and -100 V) during the deposition at 450 °C. Detailed X-ray diffraction (XRD) and atom probe tomography (APT) studies indicate that the (Hf,Ta,V,W,Zr)B2 thin films remain single-phase AlB2-structured (with randomly distributed elements at the metal-sublattice) during vacuum-annealing at temperatures up to 1200 °C. Only when increasing the annealing temperature to 1400 °C, the formation of small orthorhombic structured (V,W)B-based regions can be detected, indicating the onset of decomposition of (Hf,Ta,V,W,Zr)B2 thin films into (Hf,Ta,Zr)B2 and (V,W)B, accompanied by the formation of confined B-rich boundary regions between these phases. After annealing at 1400 °C the hardness is still very high with ~44 GPa, as the volume fraction of the newly formed (V,W)B-rich domains is small and the majority of the coating is still solid-solution (Hf,Ta,V,W,Zr)B2 with severe lattice distortions. Only at even higher Ta of 1500 and 1600 °C, H decreased to ~39 GPa.

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  • 1971.
    Kiros, Yohannes
    et al.
    KTH, Superseded Departments (pre-2005), Materials Processing.
    Lindström, Olle
    KTH.
    Kaimakis, Triantafyllos
    KTH.
    Cobalt and cobalt-based macrocycle blacks as oxygen-reduction catalysts in alkaline fuel cells1993In: Journal of Power Sources, ISSN 0378-7753, Vol. 45, no 2, p. 219-227Article in journal (Refereed)
    Abstract [en]

    The electrochemical reduction of oxygen on high surface are carbons catalyzed by cobalt and pyrolyzed macrocycles has been studied in alkaline fuel cells. Tests were also carried out with 'green black', i.e., pyrolyzed phyto-biomass. Galvanostatic polarization curves show that cobalt from cobalt acetate and fine cobalt metal power exhibit a high catalytic activity. The activity of pyrolyzed cobalt tetraphenylporphyrin (CoTPP) is due to the combined effects of the cobalt additive and the charred residue of the macrocycle. 'Green black', with chlorophyll as macrocycle black precursor, has a similar effect. The dissolution of cobalt from the electrode surface has been established. Life tests with these electrodes are reported. © 1993.

  • 1972.
    Kiros, Yohannes
    et al.
    KTH, Superseded Departments (pre-2005), Chemical Engineering and Technology.
    Schwartz, Stephan
    KTH.
    Pyrolyzed macrocycles on high surface area carbons for the reduction of oxygen in alkaline fuel cells1991In: Journal of Power Sources, ISSN 0378-7753, Vol. 36, no 4, p. 547-555Article in journal (Refereed)
    Abstract [en]

    Polarization characteristics and preparation methods of double-layer porous gas diffusion electrodes on various carbon materials in alkaline fuel cells were investigated. The electrodes with active carbon carriers were catalyzed with cobalt/iron tetraphonylporphyrin or silver. These electrodes show a potential of - 186 mV (versus Hg/HgO) at 1.0 A/cm2 when operated with oxygen at 40 °C and 5 M KOH. Various techniques such as surface area measurements, scanning (SEM) and transmission (TEM) electron microscopy in combination with energy dispersive spectroscopy (EDS) and electron energy loss spectroscopy (EELS) were used to characterize the structure and morphology of the catalyst layer.

  • 1973.
    Kishore, M. R. Ashwin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Larsson, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Ravindran, Ponniah
    Cent Univ Tamil Nadu, Dept Phys, Thiruvarur 610101, Tamil Nadu, India.;Cent Univ Tamil Nadu, SimulationCtr Atom & Nanoscale Mat, Thiruvarur 610101, Tamil Nadu, India..
    Two-Dimensional CdX/C2N (X = S, Se) Heterostructures as Potential Photocatalysts for Water Splitting: A DFT Study2020In: ACS Omega, E-ISSN 2470-1343, Vol. 5, no 37, p. 23762-23768Article in journal (Refereed)
    Abstract [en]

    Global environmental issues, in addition to limited fossil fuel resources, are being addressed by quests in search of efficient visible-light-driven water splitting catalysts for hydrogen production. The photocatalytic water splitting activities of CdX/C2N (X = S, Se) heterostructures have been investigated here using hybrid density functional theory calculations. The calculated band gaps of CdS/C2N and CdSe/C2N heterostructures are 1.48 and 2.12 eV, respectively. These are ideal band gap values that make possible harvesting of more visible light from the solar spectrum, which will result in high solar to energy conversion efficiencies. Charge density difference analysis shows that the charge redistributions mainly occur in the interface regions and that the charges transfer from the C-2N to CdX layers. It is interesting to note that the CdX/C2N heterostructures possess a type-II band alignment, where the relative band alignment of the C2N and CdX monolayers promotes a spatial separation of the electrons (that resides in C2N) and holes (that resides in CdX). Importantly, the band edges of the heterostructures straddle the water redox potential under different pH conditions. This study demonstrates that the CdS/C2N and CdSe/C-2N heterostructures are suitable materials to split water (from various sources) in different ranges of pH values.

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  • 1974.
    Kislitsyn, Dmitry A.
    et al.
    Univ Oregon, Oregon Ctr Opt Mol & Quantum Sci, Dept Chem & Biochem, Inst Mat Sci, 1253 Univ Oregon, Eugene, OR 97403 USA..
    Mills, Jon M.
    Univ Oregon, Oregon Ctr Opt Mol & Quantum Sci, Dept Chem & Biochem, Inst Mat Sci, 1253 Univ Oregon, Eugene, OR 97403 USA..
    Kocevski, Vancho
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory. Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA..
    Chiu, Sheng-Kuei
    Portland State Univ, Dept Chem, Portland, OR 97201 USA..
    DeBenedetti, William J. I.
    Portland State Univ, Dept Chem, Portland, OR 97201 USA.;Cornell Univ, Dept Chem & Chem Biol, Ithaca, NY 14853 USA..
    Gervasi, Christian F.
    Univ Oregon, Oregon Ctr Opt Mol & Quantum Sci, Dept Chem & Biochem, Inst Mat Sci, 1253 Univ Oregon, Eugene, OR 97403 USA..
    Taber, Benjamen N.
    Univ Oregon, Oregon Ctr Opt Mol & Quantum Sci, Dept Chem & Biochem, Inst Mat Sci, 1253 Univ Oregon, Eugene, OR 97403 USA..
    Rosenfield, Ariel E.
    Univ Oregon, Oregon Ctr Opt Mol & Quantum Sci, Dept Chem & Biochem, Inst Mat Sci, 1253 Univ Oregon, Eugene, OR 97403 USA..
    Eriksson, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Rusz, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Goforth, Andrea M.
    Portland State Univ, Dept Chem, Portland, OR 97201 USA..
    Nazin, George V.
    Univ Oregon, Oregon Ctr Opt Mol & Quantum Sci, Dept Chem & Biochem, Inst Mat Sci, 1253 Univ Oregon, Eugene, OR 97403 USA..
    Communication: Visualization and spectroscopy of defects induced by dehydrogenation in individual silicon nanocrystals2016In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 144, no 24, article id 241102Article in journal (Refereed)
    Abstract [en]

    We present results of a scanning tunneling spectroscopy (STS) study of the impact of dehydrogenation on the electronic structures of hydrogen-passivated silicon nanocrystals (SiNCs) supported on the Au(111) surface. Gradual dehydrogenation is achieved by injecting high-energy electrons into individual SiNCs, which results, initially, in reduction of the electronic bandgap, and eventually produces midgap electronic states. We use theoretical calculations to show that the STS spectra of midgap states are consistent with the presence of silicon dangling bonds, which are found in different charge states. Our calculations also suggest that the observed initial reduction of the electronic bandgap is attributable to the SiNC surface reconstruction induced by conversion of surface dihydrides to monohydrides due to hydrogen desorption. Our results thus provide the first visualization of the SiNC electronic structure evolution induced by dehydrogenation and provide direct evidence for the existence of diverse dangling bond states on the SiNC surfaces. Published by AIP Publishing.

  • 1975.
    Kitaguchi, Yuya
    et al.
    Kyoto University, Japan.
    Habuka, Satoru
    Kyoto University, Japan.
    Okuyama, Hiroshi
    Kyoto University, Japan.
    Hatta, Shinichiro
    Kyoto University, Japan.
    Aruga, Tetsuya
    Kyoto University, Japan.
    Frederiksen, Thomas
    Donostia International Physics Center (DIPC), Spain ; IKERBASQUE, Basque Foundation for Science, Spain.
    Paulsson, Magnus
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Ueba, Hiromu
    University of Toyama, Japan.
    Controlled switching of single-molecule junctions by mechanical motion of a phenyl ring2015In: Beilstein Journal of Nanotechnology, ISSN 2190-4286, Vol. 6, p. 2088-2095Article in journal (Refereed)
    Abstract [en]

    Mechanical methods for single-molecule control have potential for wide application in nanodevices and machines. Here we demonstrate the operation of a single-molecule switch made functional by the motion of a phenyl ring, analogous to the lever in a conventional toggle switch. The switch can be actuated by dual triggers, either by a voltage pulse or by displacement of the electrode, and electronic manipulation of the ring by chemical substitution enables rational control of the on-state conductance. Owing to its simple mechanics, structural robustness, and chemical accessibility, we propose that phenyl rings are promising components in mechanical molecular devices.

  • 1976.
    Kitz, Paul G.
    et al.
    Paul Scherrer Inst, Electrochem Lab, CH-5232 Villigen, Switzerland.
    Lacey, Matthew
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Novak, Petr
    Paul Scherrer Inst, Electrochem Lab, CH-5232 Villigen, Switzerland.
    Berg, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry. Paul Scherrer Inst, Electrochem Lab, CH-5232 Villigen, Switzerland.
    Operando EQCM-D with Simultaneous in Situ EIS: New Insights into Interphase Formation in Li Ion Batteries2019In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 91, no 3, p. 2296-2303Article in journal (Refereed)
    Abstract [en]

    An operando electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D) with simultaneous in situ electrochemical impedance spectroscopy (EIS) has been developed and applied to study the solid electrolyte interphase (SEI) formation on copper current collectors in Li-ion batteries. The findings are backed by EIS simulations and complementary analytical techniques, such as online electrochemical mass spectrometry (OEMS) and X-ray photoelectron spectroscopy (XPS). The evolution of mass and the mechanical properties of the SEI are directly correlated to the electrode impedance. Electrolyte reduction at the anode carbon active material initiates dissolution, diffusion, and deposition of reaction side products throughout the cell and increases electrolyte viscosity and the ohmic cell resistance as a result. On Cu the reduction of CuOx and HF occurs at >1.5 V and forms an initial LiF-rich interphase while electrolyte solvent reduction at <0.8 V vs Li+/Li adds a second, less rigid layer on top. Both the shear storage modulus and viscosity of the SEI generally increase upon cycling but-along with the SEI Li+ diffusion coefficient-also respond reversibly to electrode potential, likely as a result of Li+/EC interfacial concentration changes. Combined EIS-EQCM-D provides unique prospects for further studies of the highly dynamic structure-function relationships of electrode interphases in Li ion batteries.

  • 1977.
    Kitz, Paul G.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry. Paul Scherrer Inst, Electrochem Lab, CH-5232 Villigen, Switzerland..
    Lacey, Matthew
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry. Scania CV AB, SE-15187 Södertälje, Sweden..
    Novak, Petr
    Paul Scherrer Inst, Electrochem Lab, CH-5232 Villigen, Switzerland..
    Berg, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry. Paul Scherrer Inst, Electrochem Lab, CH-5232 Villigen, Switzerland..
    Operando investigation of the solid electrolyte interphase mechanical and transport properties formed from vinylene carbonate and fluoroethylene carbonate2020In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 477, article id 228567Article in journal (Refereed)
    Abstract [en]

    The electrolyte additives vinylene carbonate (VC) and fluoroethylene carbonate (FEC) are well known for increasing the lifetime of a Li-ion battery cell by supporting the formation of an effective solid electrolyte interphase (SEI) at the anode. In this study combined simultaneous electrochemical impedance spectroscopy (EIS) and operando electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D) are employed together with in situ gas analysis (OEMS) to study the influence of VC and FEC on the passivation process and the interphase properties at carbon-based anodes. In small quantities both additives reduce the initial interphase mass loading by 30-50%, but only VC also effectively prevents continuous side reactions and improves anode passivation significantly. VC and FEC are both reduced at potentials above 1 V vs. Li+/Li in the first cycle and change the SEI composition which causes an increase of the SEI shear storage modulus by over one order of magnitude in both cases. As a consequence, the ion diffusion coefficient and conductivity in the interphase is also significantly affected. While small quantities of VC in the initial electrolyte increase the SEI conductivity, FEC decomposition products hinder charge transport through the SEI and thus increase overall anode impedance significantly.

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  • 1978.
    Kitz, Paul G.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry. Paul Scherrer Inst, Electrochem Lab, CH-5232 Villigen, Switzerland.
    Novak, Petr
    Paul Scherrer Inst, Electrochem Lab, CH-5232 Villigen, Switzerland..
    Berg, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry. Paul Scherrer Inst, Electrochem Lab, CH-5232 Villigen, Switzerland.
    Influence of Water Contamination on the SEI Formation in Li-Ion Cells: An Operando EQCM-D Study2020In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 12, no 13, p. 15934-15942Article in journal (Refereed)
    Abstract [en]

    The interphase formation on carbon (C) anodes in LiPF6/EC + DEC Li-ion battery electrolyte is analyzed by combining operando electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D) with in situ online electrochemical mass spectrometry (OEMS). EQCM-D enables unique insights into the anode solid electrolyte interphase (SEI) mass/thickness, its viscoelastic properties, and changes of electrolyte viscosity during the initial formation cycles. The interphase in the pure electrolyte is relatively soft (G(SEI)' approximate to 0.2 MPa, eta(SEI) approximate to mPa s) and changes its viscoelastic properties dynamically as a function of the electrode potential. With increasing electrolyte water content, the SEI becomes thicker and much more rigid. Doubly labeled (D2O)-O-18 is added to the electrolyte in order to precisely track the reaction pathway of water at the anode by OEMS. In the first cycle between 2.6 and 1.7 V versus Li+/Li, water is reduced, and hydroxide ions initiate an autocatalytic hydrolysis of EC. With large amounts of water initially present in the electrolyte, most of the formed CO2 gas is scavenged by reactions with hydroxide and alkoxide ions, forming a thick, rigid, and Li2CO3-rich early interphase on the C anode. This layer alleviates the following electrolyte decomposition processes and slows the reduction of EC < 1 V versus Li+/Li.

  • 1979.
    Kizling, Michal
    et al.
    Univ Warsaw, Fac Chem, PL-02093 Warsaw, Poland..
    Draminska, Sylwia
    Univ Warsaw, Fac Chem, PL-02093 Warsaw, Poland..
    Stolarczyk, Krzysztof
    Univ Warsaw, Fac Chem, PL-02093 Warsaw, Poland..
    Tammela, Petter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Wang, Zhaohui
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Bilewicz, Renata
    Univ Warsaw, Fac Chem, PL-02093 Warsaw, Poland..
    Biosupercapacitors for powering oxygen sensing devices2015In: Bioelectrochemistry, ISSN 1567-5394, E-ISSN 1878-562X, Vol. 106, p. 34-40Article in journal (Refereed)
    Abstract [en]

    A biofuel cell comprising electrodes based on supercapacitive materials - carbon nanotubes and nanocellulose/polypyrrole composite was utilized to power an oxygen biosensor. Laccase Trametes versicolor, immobilized on naphthylated multi walled carbon nanotubes, and fructose dehydrogenase, adsorbed on a porous polypyrrole matrix, were used as the cathode and anode bioelectrocatalysts, respectively. The nanomaterials employed as the supports for the enzymes increased the surface area of the electrodes and provide direct contact with the active sites of the enzymes. The anode modified with the conducting polymer layer exhibited significant pseudocapacitive properties providing superior performance also in the high energy mode, e.g., when switching on/off the powered device. Three air-fructose biofuel cells connected in a series converted chemical energy into electrical giving 2 mW power and open circuit potential of 2 V. The biofuel cell system was tested under various externally applied resistances and used as a powering unit for a laboratory designed two-electrode minipotentiostat and a laccase based sensor for oxygen sensing. Best results in terms of long time measurement of oxygen levels were obtained in the pulse mode -45 s for measurement and 15 min for self-recharging of the powering unit.

  • 1980.
    Kizling, Michal
    et al.
    Warsaw University.
    Stolarczyk, Krzysztof
    Warsaw University.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Bilewicz, Renata
    Warsaw University.
    Application of cellulose/conductive polymer paper as free standing matrix for enzyme immobilization in enzymatic fuel cell2016Conference paper (Other academic)
  • 1981. Kjellman, Tomas
    et al.
    Asahina, Shunsuke
    Schmitt, Julien
    Imperor-Clerc, Marianne
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Korea Advanced Institute of Science & Technology (KAIST), South Korea.
    Alfredsson, Viveka
    Direct Observation of Plugs and Intrawall Pores in SBA-15 Using Low Voltage High Resolution Scanning Electron Microscopy and the Influence of Solvent Properties on Plug-Formation2013In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 25, no 20, p. 4105-4112Article in journal (Refereed)
    Abstract [en]

    Through the use of low voltage high resolution scanning electron microscopy (LV-HRSEM) we have studied the fine details of the intricate pore structure of SBA-15. Intrawall pores and deviations from the ideal and uniform cylindrical pores are clearly observed, and we report for the first time the direct observation of plugs in the pores. N-2-sorption measurements confirm their existence. LV-HRSEM provides an opportunity to quantify the frequency of occurrence of plugs within the pore structure. The rate of mesophase formation, followed with in situ small angle X-ray scattering (SAXS) under different solvent conditions, is shown to have a significant influence on the development of plugs and how frequently they occur. We suggest a mechanism explaining the existence of the plugs, providing means for a better understanding and control over material properties.

  • 1982.
    Kjellsdotter Ivert, Linea
    Swedish National Road and Transport Research Institute (VTI).
    Towards a sustainable circular system of textiles in the Nordics2022Report (Other (popular science, discussion, etc.))
    Abstract [en]

    The Nordic countries are big consumers of home textiles and clothing, but the textiles do not stay here for a long time. Although some clothes and home textiles are reused among friends, family, sold on marketplaces or donated to non-profit organizations (NGO), most end up in the residual waste and are incinerated. This is leading to huge material and resource lost since over fifty percent of the textiles could have been reused or recycled. Of the textiles that are separately collected, the majority are exported abroad for sorting and reuse whereas a tiny fraction is fiber-to-fiber recycled. 

     

    Seeing that the textile industry is one of the most resource consuming industries with a high environmental impact it is important that the Nordic countries increase the collection and recycling rates and reuse more locally. It will not be possible to export EOL textiles in the same way as before. Around 40 countries have stopped importing EOL textiles and the EU is setting requirements for separate collection from 2025. This will mean that volumes of EOL textiles will increase in Europe at the same time as it will be increasingly difficult to find outlets for these volumes. As collection rates increase, so will the proportion of textiles that cannot be reused but hopefully be recycled (recyclables). There is no organized collection for recyclables, but several innovative initiatives are happening within this area, not least in the Nordic countries, where many automated sorting and recycling facilities are emerging.

     

    The SATIN project focuses on increasing circularity of EOL textile in the Nordic region and has a strong focus on supply chain management (SCM). SCM relates to balancing the supply and demand of materials to achieve efficiency in the material flow of EOL textiles and related information, and monetary flows as well as collaboration between actors in the EOL textile value chain. The purpose of the SATIN project is to develop and test solutions that can address the EOL textile collection and sorting challenges by taking a SCM perspective. 

     

    In the project we have 1) Mapped and identified challenges and opportunities in the current system by interviewing main actors in the value chain of EOL textiles in Norway, Sweden, Denmark, and Finland, 2) Analyzed nine pilot studies of different collection methods. The pilots differ in terms of who organize the collection and sorting, the geographical area in which the collection service is offered, type of collection method, and if collection is carried out in one or two fractions, 3) Estimated volumes of recyclable textiles and their fiber composition and compared this supply with the current and upcoming sorting and recycling capacity (demand) in each country and in the whole Nordic area. 

     

    Our results show there are large similarities between the actors in the Nordic countries when it comes to challenges and opportunities in the value chain of EOL textiles. Main challenges can be connected to lack of scale, low profit, no demand, and lack of data whereas opportunities are seen in collaboration, centralization and understanding/finding a market for EOL textiles. Connected to collection methods it was found that it is difficult to compare different methods because there are so many factors at play. However, it became clear that regardless of the collection method, the role of the consumer is very important in scaling up collection.  Connected to recyclables our results show that the upcoming automatic sorting and recycling capacity in the Nordic region will be sufficient to deal with the total recyclable fraction, except for some of the synthetic fibers. However, there are imbalances within each country raising a need for collaboration among countries. To make local automatic sorting and recycling possible, it is important to find solutions for pre-sorting within the Nordic region. 

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  • 1983.
    Kjellsdotter Ivert, Linea
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Towards a sustainable circular system of textiles in the Nordics2022Report (Other academic)
    Abstract [en]

    The SATIN project focuses on increasing circularity of EOL textile in the Nordic region and has a strong focus on supply chain management (SCM). SCM relates to balancing the supply and demand of materials to achieve efficiency in the material flow of EOL textiles and related information, and monetary flows as well as collaboration between actors in the EOL textile value chain. The purpose of the SATIN project is to develop and test solutions that can address the EOL textile collection and sorting challenges by taking a SCM perspective. 

    In the project we have 1) Mapped and identified challenges and opportunities in the current system by interviewing main actors in the value chain of EOL textiles in Norway, Sweden, Denmark, and Finland, 2) Analyzed nine pilot studies of different collection methods, 3) Estimated volumes of recyclable textiles and their fiber composition and compared this supply with the current and upcoming sorting and recycling capacity (demand) in each country and in the whole Nordic area. 

    Our results show there are large similarities between the actors in the Nordic countries when it comes to challenges and opportunities in the value chain of EOL textiles. Main challenges can be connected to lack of scale, low profit, no demand, and lack of data whereas opportunities are seen in collaboration, centralization and understanding/finding a market for EOL textiles. Connected to collection methods it was found that it is difficult to compare different methods because there are so many factors at play. However, it became clear that regardless of the collection method, the role of the consumer is very important in scaling up collection.  Connected to recyclables our results show that the upcoming automatic sorting and recycling capacity in the Nordic region will be sufficient to deal with the total recyclable fraction, except for some of the synthetic fibers. However, there are imbalances within each country raising a need for collaboration among countries.

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  • 1984.
    Klarbring, Johan
    et al.
    Linköping Univ, Dept Phys Chem & Biol IFM, Theoret Phys Div, S-58183 Linköping, Sweden..
    Singh, Utkarsh
    Linköping Univ, Dept Phys Chem & Biol IFM, Theoret Phys Div, S-58183 Linköping, Sweden..
    Simak, Sergei I
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory. Linköping Univ, Dept Phys Chem & Biol IFM, Theoret Phys Div, S-58183 Linköping, Sweden..
    Abrikosov, Igor A.
    Linköping Univ, Dept Phys Chem & Biol IFM, Theoret Phys Div, S-58183 Linköping, Sweden..
    Electronic structure of the magnetic halide double perovskites Cs-2(Ag, Na)FeCl6 from first principles2023In: Physical Review Materials, E-ISSN 2475-9953, Vol. 7, no 4, article id 044605Article in journal (Refereed)
    Abstract [en]

    A family of magnetic halide double perovskites (HDPs) have recently attracted attention due to their potential to broaden application areas of halide double perovskites into, e.g., spintronics. Up to date the theoretical modeling of these systems have relied on primitive approximations to the density functional theory (DFT). In this paper, we study structural, electronic and magnetic properties of the Fe3+-containing HDPs Cs2AgFeCl6 and Cs2NaFeCl6 using a combination of more advanced DFT-based methods, including DFT + U, hybrid-DFT, and treatments of various magnetic states. We examine the effect of varying the effective Hubbard parameter, U-eff, in DFT + U and the mixing-parameter, alpha, in hybrid DFT on the electronic structure and structural properties. Our results reveal a set of localized Fe(d) states that are highly sensitive to these parameters. Cs2AgFeCl6 and Cs2NaFeCl6 are both antiferromagnets with Neel temperatures well below room temperature and are thus in their paramagnetic (PM) state at the external conditions relevant to most applications. Therefore, we have examined the effect of disordered magnetism on the electronic structure of these systems and find that while Cs2NaFeCl6 is largely unaffected, Cs2AgFeCl6 shows significant renormalization of its electronic band structure.

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  • 1985.
    Klarbring, Johan
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Vekilova, Olga Yu.
    KTH Royal Institute Technology, Sweden; Uppsala University, Sweden.
    Nilsson, Johan O.
    KTH Royal Institute Technology, Sweden.
    Skorodumova, Natalia V.
    KTH Royal Institute Technology, Sweden; Uppsala University, Sweden.
    Simak, Sergey
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Ionic conductivity in Sm-doped ceria from first-principles non-equilibrium molecular dynamics2016In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 296, p. 47-53Article in journal (Refereed)
    Abstract [en]

    Sm-doped ceria is a prospective electrolyte material for intermediate-temperature solid-oxide fuel cells (IT-SOFC). Equilibrium ab initio molecular dynamics (AIMD) studies of oxygen ion diffusion in this material are currently impractical due to the rareness of diffusive events on the accessible timescale. To overcome this issue we have performed ab initio non-equilibrium molecular dynamics calculations of Sm-doped ceria using the color diffusion algorithm. Applying an external force field we have been able to increase the frequency of diffusive events over the simulation time, while keeping the physical mechanism of diffusion intact. We have investigated the temperature dependence of the maximum strength of the applied external field that could be used while maintaining the response of the system in a linear regime. This allows one to obtain the diffusivity at zero field. The bulk ionic conductivity has been calculated and found to match the experimental data well. We have also compared the description of the diffusion process by our method to previous findings and show that the migration mechanism and site preference of oxygen vacancies with respect to the Sm dopants is well reproduced. (C) 2016 Elsevier B.V. All rights reserved.

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  • 1986.
    Klaus-Joerger, Tanja
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Joerger, Ralph
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Olsson, Eva
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Granqvist, Claes Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Bacteria as workers in the living factory: metal-accumulating bacteria and their potential for materials science2001In: Trends in Biotechnology, ISSN 0167-7799, E-ISSN 1879-3096, Vol. 19, no 1, p. 15-20Article, review/survey (Refereed)
    Abstract [en]

    Metal micro-/nano-particles with suitable chemical modification can be organized into new ceramic–metal (cermet) or organic–metal (orgmet) composites or structured materials. These materials are attracting significant attention because of their unique structures and highly optimized properties. However, the synthesis of composite materials with inhomogeneities on the nanometer or sub-micrometer scale is a continuing challenge in materials science. Many industrial physical and chemical surface-coating processes using conventional techniques are both energy and cost inefficient and require sophisticated instrumentation. In the future, biology might offer a superior option.

  • 1987. Kleber, C.
    et al.
    Weissenrieder, Jonas
    KTH, Superseded Departments (pre-2005), Materials Science and Engineering.
    Schreiner, M.
    Leygraf, Christofer
    KTH, Superseded Departments (pre-2005), Materials Science and Engineering.
    Comparison of the early stages of corrosion of copper and iron investigated by in situ TM-AFM2002In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 193, no 1-4, p. 245-253Article in journal (Refereed)
    Abstract [en]

    Tapping mode atomic force microscopy (TM-AFM) was used for the investigation of the early stages of atmospheric corrosion of pure copper and pure iron. The information obtained by this method is the change of the topography of the sample surfaces with emphasis on the. shape and lateral distribution of the corrosion products grown within the first 1300 min of weathering. Investigations were carried out in synthetic air at 80 and 90% relative humidity (RH) with additions of 250 ppb SO2 and 250 ppb NO2. On a polished copper surface the growth of corrosion products could be observed already at 80% RH and 250 ppb SO2, whereas an iron surface had to be exposed to 90% RH with 250 ppb SO2 and 250 ppb NO, to produce detectable changes on the surface.

  • 1988.
    Klechikov, Alexey G.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Mercier, Guillaume
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Merino, Pilar
    Blanco, Santiago
    Merino, Cesar
    Talyzin, Alexandr V.
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Hydrogen storage in bulk graphene-related materials2015In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 210, p. 46-51Article in journal (Refereed)
    Abstract [en]

    Hydrogen sorption properties of graphene-related materials were studied by gravimetric and volumetric methods at 2931< and 77K. Rapid thermal exfoliation of different types of graphite oxide (GO) precursors yielded samples with maximal surface areas up to 850 m(2)/g, whereas surface areas up to 2300 m(2)/g were achieved by post-exfoliation activation treatments. Therefore, hydrogen storage parameters of graphene materials could be evaluated in a broad range of surface areas. The H-2 uptake vs surface area trend revealed in this study shows that hydrogen storage by graphene materials do not exceed 1 Wt% at 120 Bar H-2 at ambient temperatures. Linear increase of hydrogen adsorption vs surface area was observed at 77 K with maximal observed value of similar to 5 Wt% for 2300 m(2)/g sample. It can be concluded that bulk graphene samples obtained using graphite oxide exfoliation and activation follow standard for other nanostructured carbons hydrogen uptake trends and do not demonstrate superior hydrogen storage parameters reported in several earlier studies. Nevertheless, graphene remains to be one of the best materials for physisorption of hydrogen, especially at low temperatures.

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  • 1989.
    Klechikov, Alexey
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Sun, Jinhua
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Hu, Guangzhi
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Zheng, Mingbo
    Wågberg, Thomas
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Talyzin, Alexandr V.
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Graphene decorated with metal nanoparticles: Hydrogen sorption and related artefacts2017In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 250, p. 27-34Article in journal (Refereed)
    Abstract [en]

    Hydrogen sorption by reduced graphene oxides (r-GO) is not found to increase after decoration with Pd and Pt nanoparticles. Treatments of metal decorated samples using annealing under hydrogen or air were tested as a method to create additional pores by effects of r-GO etching around nanoparticles. Increase of Specific Surface Area (SSA) was observed for some air annealed r-GO samples. However, the same treatments applied to activated r-GO samples with microporous nature and higher surface area result in breakup of structure and dramatic decrease of SSA. Our experiments have not revealed effects which could be attributed to spillover in hydrogen sorption on Pd or Pt decorated graphene. However, we report irreversible chemisorption of hydrogen for some samples which can be mistakenly assigned to spillover if the experiments are incomplete.

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  • 1990.
    Klechikov, Alexey
    et al.
    Umea Univ, Dept Phys, SE-90187 Umea, Sweden.
    Sun, Jinhua
    Umea Univ, Dept Phys, SE-90187 Umea, Sweden.
    Vorobiev, Alexei
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Talyzin, Alexandr V.
    Umea Univ, Dept Phys, SE-90187 Umea, Sweden.
    Swelling of Thin Graphene Oxide Films Studied by in Situ Neutron Reflectivity2018In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 122, no 24, p. 13106-13116Article in journal (Refereed)
    Abstract [en]

    Permeation of multilayered graphene oxide (GO) membranes by polar solvents is known to correlate with their swelling properties and amount of sorbed solvent. However, quantitative estimation of sorption using standard (e.g., gravimetric) methods is technically challenging for few nanometers thick GO membranes/films exposed to solvent vapors. Neutron reflectivity (NR) was used here to evaluate the amount of solvents intercalated into the film which consists of only similar to 31.5 layers of GO. Analysis of NR data recorded from the GO film exposed to vapors of polar solvents provides information about change of film thickness due to swelling, amount of intercalated solvent, and selectivity in sorption of solvents from binary mixtures. A quantitative study of GO film sorption was performed for D2O, d-methanol, ethanol, dimethyl sulfoxide (DMSO), acetonitrile, dimethylformamide (DMF), and acetone. Using isotopic contrast, we estimated selectivity in sorption of ethanol/d-methanol mixtures by the GO film. Estimation of sorption selectivity was also performed for D2O/DMF, D2O/DMSO, and D2O/acetonitrile binary mixtures. Sorption of polar solvents was compared for the thin GO film, micrometer thick free standing GO membranes, and graphite oxide powders.

  • 1991.
    Klekotka, U.
    et al.
    Univ Bialystok, Inst Chem, Ciolkowskiego 1K, PL-15245 Bialystok, Poland.
    Satula, D.
    Univ Bialystok, Fac Phys, Ciolkowskiego 1L, PL-15245 Bialystok, Poland.
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solid State Physics.
    Kalska-Szostko, B.
    Univ Bialystok, Inst Chem, Ciolkowskiego 1K, PL-15245 Bialystok, Poland.
    Layered magnetite nanoparticles modification: synthesis, structure, and magnetic characterization2020In: Arabian Journal of Chemistry, ISSN 1878-5352, E-ISSN 1878-5379 , Vol. 13, no 1, p. 1323-1334Article in journal (Refereed)
    Abstract [en]

    Core-shell and multilayered nanoparticles based on magnetite core with different metallic spacing and over-layers are prepared in one pot synthesis and characterized. The spacer layers were made from Au, Cu or Ag precursors. The nanoparticles were fabricated by a modified chemical seed based method. The obtained nanoparticles were examined by X-ray diffraction, Energy-dispersive X-ray spectroscopy, Transmission Electron Microscopy, Differential Scanning Calorimetry and Infrared spectroscopy. Magnetic properties of the nanoparticles were tested by Mossbauer spectroscopy and Magnetometry. Magnetization and Mossbauer measurements show that the presence of the metallic layers influences the magnetic state of the particles. XRD and EDX confirm layered structures of nanoparticles. Proposed synthesis allows for fabrication of layered particles with controlled morphology and register properties changes which are related to the nature of each subsequent layer.

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  • 1992.
    Klement, W. J. Niels
    et al.
    Univ Groningen, Stratingh Inst Chem, Fac Sci & Engn, Mol Inorgan Chem, Nijenborgh 4, NL-9747 AG Groningen, Netherlands.;Univ Groningen, Groningen Res Inst Pharm, Pharmaceut Anal, Antonius Deusinglaan 1, NL-9700 AD Groningen, Netherlands..
    Steen, Jorn D.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström. Univ Groningen, Stratingh Inst Chem, Fac Sci & Engn, Mol Inorgan Chem, Nijenborgh 4, NL-9747 AG Groningen, Netherlands..
    Browne, Wesley R.
    Univ Groningen, Stratingh Inst Chem, Fac Sci & Engn, Mol Inorgan Chem, Nijenborgh 4, NL-9747 AG Groningen, Netherlands..
    Selective Analysis of Redox Processes at the Electrode Interface with Time-Resolved Raman Spectroscopy2023In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 39, no 30, p. 10383-10394Article in journal (Refereed)
    Abstract [en]

    Electrochemistry and electrochemical reactions are increasinglyimportant in the transition to a sustainable chemical industry. Theelectron transfer that drives such reactions takes place within nanometersof the electrode surface, and follow-up chemical reactions take placewithin the diffusion layer. Hence, understanding electrochemical reactionsrequires time-, potential-, and spatially resolved analysis. The confocalnature of Raman spectroscopy provides high spatial resolution, inaddition to detailed information on molecular structure. The intrinsicweakness of nonresonant Raman scattering, however, is not sensitiveenough for relatively minor changes to the solution resulting fromreactions at the electrode interface. Indeed, the limit of detectionis typically well above the concentrations used in electrochemicalstudies. Here, we show that surface-enhanced Raman scattering (SERS)and resonance Raman (rR) spectroscopy allow for spatially and time-resolvedanalysis of solution composition at (<1-2 nm) and near (within5 & mu;m) the electrode surface, respectively, in a selective mannerfor species present at low (<1 mM) concentrations. We show changesin concentration of species at the electrode surface, without theneed for labels, specific adsorption, or resonance enhancement, usinga SERS-active gold electrode prepared readily by electrochemical surfaceroughening. A combination of smooth and roughened gold electrodesis used to distinguish between surface and resonance enhancement usingthe well-known redox couples ferrocene and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonicacid) (ABTS). We discuss the impact of specific adsorption on thespectral analysis with the ruthenium(II) polypyridyl complex, [Ru(bpy)(3)](2+). The dual function of the electrode (surfaceenhancement and electron transfer) in the analysis of solution processesis demonstrated with the reversible oxidation of TMA (4,N,N-trimethylaniline), where transient soluble species are identifiedin real time, with rapid spectral acquisition, making use of localizedenhancement. We anticipate that this approach will find use in elucidatingelectro(catalytic) reactions at electrode interfaces.

  • 1993.
    Klingstedt, Miia
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Characterizing cavity containing materials using electron microscopy: A study of metal oxides, mesoporous crystals and porous material containing nanosized metal-particles2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis concerns the characterization of novel materials by utilizing electron microscopy techniques. The examined materials contain cavities with certain attributes that enables desired properties for applications such as gas separation, catalysis and fuel cells. The specimens concerned herein belong to the following groups of materials: Metal oxides in the Sb-W-Mo-O system; ordered mesoporous silicas and carbons; hollow spheres containing Au-nanoparticles; zeolite LTA incorporated with mesopores; metal organic frameworks doped with nickel.

    With scanning electron microscopy (SEM) and transmission electron microscopy (TEM) you get vast possibilities within the field of characterization. This thesis utilizes conventional electron microscopy techniques such as imaging, energy-dispersive spectroscopy and electron diffraction as well as reconstruction techniques, such as exit-wave reconstruction, electron tomography and electron crystallography. Furthermore, the sample preparation technique cross-section polishing has been used in conjunction with low voltage SEM studies.

    The scientific approach is to gain knowledge of nano-sized cavities in materials, in particular their shape, size and content. The cavities often have irregularities that originates from the synthesis procedure. In order to refine the synthesis and to understand the properties of the material it is required to carefully examine the local variations. Therefore average characterization techniques such as crystallography needs to be combined with local examination techniques such as tomography. However, some of the materials are troublesome to investigate since they to some extent bring limitations to or gets easily damaged by the applied characterization technique. For the development of novel materials it is essential to find means of overcoming also these obstacles.

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  • 1994.
    Klingstedt, Miia
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Miyasaka, Keiichi
    Kimura, Kosuke
    Gu, Dong
    Wan, Ying
    Zhao, Dongyuan
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Advanced electron microscopy characterization for pore structure of mesoporous materials; a study of FDU-16 and FDU-182011In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 21, no 35, p. 13664-13671Article in journal (Refereed)
    Abstract [en]

    We present a comprehensive analysis for pore structures of cage-type ordered mesoporous carbons (OMCs) using various electron microscopy techniques in addition to conventional nitrogen adsorption isotherm studies. The benefits and drawbacks of these techniques are evaluated, and it is shown that they are complementary to each other. Knowledge of the structural properties, pore sizes, and connectivity gives insight into the synthesis strategies and how they are affecting the material properties that are useful within the possible applications. Herein, focus is put on the two OMCs with Im (3) over barm and Fm (3) over barm symmetries specified by FDU-16 and FDU-18. The central techniques used in this study are high resolution scanning electron microscopy combined with cross-section polisher and three-dimensional reconstruction methods (electron tomography and electron crystallography) based on transmission electron microscopy observations.

  • 1995.
    Klingstedt, Miia
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Sundberg, Margareta
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Eriksson, Lars
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Haigh, Sara
    Kirkland, Angus
    Gruner, Daniel
    De Backer, Annick
    Van Aert, Sandra
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Exit wave reconstruction from focal series of HRTEM images, single crystal XRD and total energy studies on SbxWO3+y (x~0.11)Article in journal (Refereed)
  • 1996.
    Klingstedt, Miia
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Sundberg, Margareta
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Eriksson, Lars
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Haigh, Sarah
    Kirkland, Angus
    Gruener, Daniel
    De Backer, Annick
    Van Aert, Sandra
    Terasaki, Osamu
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Exit wave reconstruction from focal series of hrtem images, single crystal xrd and total energy studies on sbxwo3+y (x similar to 0.11)2012In: Zeitschrift fur Kristallographie, ISSN 0044-2968, Vol. 227, no 6, p. 341-349Article in journal (Refereed)
    Abstract [en]

    A new tungsten bronze in the Sb-W-O system has been prepared in a solid state reaction from Sb2O3, WO3 and W metal powder. The average structure was determined by single crystal X-ray diffraction. SbxWO3+y (x similar to 0.11) crystallizes in the orthorhombic space group Pm2(1)n (no. 31), a = 27.8135(9) angstrom, b = 7.3659(2) angstrom and c = 3.8672(1) angstrom. The structure belongs to the (n)-ITB class of intergrowth tungsten bronzes. It contains slabs of hexagonal channels formed by six WO6 octahedra. These slabs are separated by three layers of WO6 octahedra that are arranged in a WO3-type fashion. The WO6 octahedra share all vertices to build up a three-dimensional framework. The hexagonal channels are filled with Sb atoms to similar to 80% and additional 0 atoms. The atoms are shifted out of the center of the channels. Exit-wave reconstruction of focal series of high resolution-transmission-electron-microscope (HRTEM) images combined with statistical parameter estimation techniques allowed to study local ordering in the channels. Sb atoms in neighbouring channels tend to be displaced in the same direction, which is in agreement with total energy calculations on ordered structure models, but the ratio of the occupation of the two possible Sb sites varies from channel to channel. The structure of SbxWO3+y exhibits pronounced local modulations.

  • 1997.
    Klipfel, Nadja
    et al.
    Ecole Polytech Fed Lausanne EPFL Valais Wallis, Inst Chem Sci & Engn, Grp Mol Engn Funct Mat, CH-1951 Sion, Switzerland..
    Kanda, Hiroyuki
    Ecole Polytech Fed Lausanne EPFL Valais Wallis, Inst Chem Sci & Engn, Grp Mol Engn Funct Mat, CH-1951 Sion, Switzerland..
    Sutanto, Albertus Adrian
    Ecole Polytech Fed Lausanne EPFL Valais Wallis, Inst Chem Sci & Engn, Grp Mol Engn Funct Mat, CH-1951 Sion, Switzerland..
    Mensi, Mounir
    Ecole Polytech Fed Lausanne EPFL Valais Wallis, Inst Chem Sci & Engn, Grp Mol Engn Funct Mat, CH-1951 Sion, Switzerland..
    Igci, Cansu
    Ecole Polytech Fed Lausanne EPFL Valais Wallis, Inst Chem Sci & Engn, Grp Mol Engn Funct Mat, CH-1951 Sion, Switzerland..
    Leifer, Klaus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Material Science. Ecole Polytech Fed Lausanne EPFL Valais Wallis, Inst Chem Sci & Engn, Grp Mol Engn Funct Mat, CH-1951 Sion, Switzerland..
    Brooks, Keith
    Ecole Polytech Fed Lausanne EPFL Valais Wallis, Inst Chem Sci & Engn, Grp Mol Engn Funct Mat, CH-1951 Sion, Switzerland..
    Kinge, Sachin
    Toyota Motor Co Ltd, Adv Technol Div, Toyota Motor Tech Ctr, B-1930 Zaventem, Belgium..
    Roldan-Carmona, Cristina
    Ecole Polytech Fed Lausanne EPFL Valais Wallis, Inst Chem Sci & Engn, Grp Mol Engn Funct Mat, CH-1951 Sion, Switzerland.;Univ Valencia, Inst Ciencia Mol ICMol, C-J Beltran 2, Paterna 46980, Spain..
    Momblona, Cristina
    Ecole Polytech Fed Lausanne EPFL Valais Wallis, Inst Chem Sci & Engn, Grp Mol Engn Funct Mat, CH-1951 Sion, Switzerland..
    Dyson, Paul J.
    Ecole Polytech Fed Lausanne EPFL Valais Wallis, Inst Chem Sci & Engn, Grp Mol Engn Funct Mat, CH-1951 Sion, Switzerland..
    Nazeeruddin, Mohammad Khaja
    Ecole Polytech Fed Lausanne EPFL Valais Wallis, Inst Chem Sci & Engn, Grp Mol Engn Funct Mat, CH-1951 Sion, Switzerland..
    Mechanistic Insights into the Role of the Bis(trifluoromethanesulfonyl) imide Ion in Coevaporated p-i-n Perovskite Solar Cells2021In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 13, no 44, p. 52450-52460Article in journal (Refereed)
    Abstract [en]

    Hybrid lead halide perovskites have reached comparable efficiencies to state-of-the-art silicon solar cell technologies. However, a remaining key challenge toward commercialization is the resolution of the perovskite device instability. In this work, we identify for the first time the mobile nature of bis-(trifluoromethanesulfonyl)imide (TFSI-), a typical anion extensively employed in p-type dopants for 2,2'7,7'-tetrakis(N,N-di-p-methoxyphenylamine)-9,9'spirofluorene (spiro-OMeTAD). We demonstrate that TFSI- can migrate through the perovskite layer via the grain boundaries and accumulate at the perovskite/electrontransporting layer (ETL) interface. Our findings reveal that the migration of TFSI- enhances the device performance and stability, resulting in highly stable p-i-n cells that retain 90% of their initial performance after 1600 h of continuous testing. Our systematic study, which targeted the effect of the nature of the dopant and its concentration, also shows that TFSI- acts as a dynamic defect-healing agent, which self-passivates the perovskite crystal defects during the migration process and thereby decreases nonradiative recombination pathways.

  • 1998.
    Kluge, Regina M.
    et al.
    Tech Univ Munich, Lehrstuhl Funkt Mat, Phys Dept, James Franck Str 1, D-85748 Garching, Germany..
    Saxena, Nitin
    Tech Univ Munich, Lehrstuhl Funkt Mat, Phys Dept, James Franck Str 1, D-85748 Garching, Germany..
    Chen, Wei
    Tech Univ Munich, Lehrstuhl Funkt Mat, Phys Dept, James Franck Str 1, D-85748 Garching, Germany..
    Koerstgens, Volker
    Tech Univ Munich, Lehrstuhl Funkt Mat, Phys Dept, James Franck Str 1, D-85748 Garching, Germany..
    Schwartzkopf, Matthias
    DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Zhong, Qi
    Zhejiang Sci Tech Univ, Key Lab Adv Text Mat & Mfg Technol, Minist Educ, Hangzhou 310018, Peoples R China..
    Roth, Stephan V.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Mueller-Buschbaum, Peter
    Tech Univ Munich, Lehrstuhl Funkt Mat, Phys Dept, James Franck Str 1, D-85748 Garching, Germany.;Heinz Maier Leibnitz Zentrum, Lichtenbergstr 1, D-85748 Garching, Germany..
    Doping Dependent In-Plane and Cross-Plane Thermoelectric Performance of Thin n-Type Polymer P(NDI2OD-T2) Films2020In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 30, no 28, article id 2003092Article in journal (Refereed)
    Abstract [en]

    Thermoelectric generators pose a promising approach in renewable energies as they can convert waste heat into electricity. In order to build high efficiency devices, suitable thermoelectric materials, both n- and p-type, are needed. Here, the n-type high-mobility polymer poly[N,N '-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5 '-(2,2 '-bithiophene) (P(NDI2OD-T2)) is focused upon. Via solution doping with 4-(1,3-dimethyl-2,3-dihydro-1H-benzoimidazol-2-yl)-N,N-diphenylaniline (N-DPBI), a maximum power factor of (1.84 +/- 0.13) mu W K-2 m(-1) is achieved in an in-plane geometry for 5 wt% dopant concentration. Additionally, UV-vis spectroscopy and grazing-incidence wide-angle X-ray scattering are applied to elucidate the mechanisms of the doping process and to explain the discrepancy in thermoelectric performance depending on the charge carriers being either transported in-plane or cross-plane. Morphological changes are found such that the crystallites, built-up by extended polymer chains interacting via lamellar and pi-pi stacking, re-arrange from face- to edge-on orientation upon doping. At high doping concentrations, dopant molecules disturb the crystallinity of the polymer, hindering charge transport and leading to a decreased power factor at high dopant concentrations. These observations explain why an intermediate doping concentration of N-DPBI leads to an optimized thermoelectric performance of P(NDI2OD-T2) in an in-plane geometry as compared to the cross-plane case.

  • 1999. Klyndyuk, A. I.
    et al.
    Khort, A. A.
    Thermophysical properties of BiFeO3, Bi0.91Nd0.09FeO3, and BiFe0.91Mn0.09O3 multiferroics at high temperatures2016In: Physics of the solid state, ISSN 1063-7834, E-ISSN 1090-6460, Vol. 58, no 6, p. 1285-1288Article in journal (Refereed)
    Abstract [en]

    The thermal diffusion, heat capacity, and thermal conductivity of BiFeO3, Bi0.91Nd0.09FeO3, and BiFe0.91Mn0.09O3 multiferroics have been studied at high temperatures (300–1120 K). The dominant mechanisms of phonon transfer in the regions of the antiferromagnetic and ferroelectric phase transitions have been determined. The temperature dependence of the mean free path of phonons has been found.

  • 2000. Klyndyuk, A. I.
    et al.
    Khort, A. A.
    Thermophysical Properties of Solid Solutions of Bi1 – xNdxFe1 – xMnxO3 (x = 0.03, 0.09) Multiferroics at High Temperatures2019In: High Temperature, ISSN 0018-151X, E-ISSN 1608-3156, Vol. 57, no 2, p. 186-189Article in journal (Refereed)
    Abstract [en]

    Abstract: The thermal diffusivity, thermal conductivity, and specific heat of solid solutions of Bi1–xNdxFe1 – xMnxO3 (x = 0.03, 0.09) multiferroics have been studied in a wide temperature range (above room temperature). It is established that substitutions Nd3+ → Bi3+ and Mn3+ → Fe3+ in BiFeO3 lead to a decrease in the thermal diffusivity and thermal conductivity of Bi1–xNdxFe1–xMnxO3 solid solutions and reduce the temperatures of antiferromagnetic and ferroelectric orderings. The temperature dependence of the phonon mean free path is found. The factors limiting the phonon transfer in samples are determined. 

37383940414243 1951 - 2000 of 4645
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