Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Gold-Based Nanoparticles and Thin Films: Applications to Green Nanotechnology
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The use of gold-based nanoparticles and thin films is very promising when it comes to improving several green nanotechnologies. Therefore, in order to further their use in applications such as electrochromic devices, photovoltaics, light-emitting diodes and photocatalysis, the aim of this work was to study the growth of gold-based nanoparticles and thin films.

All depositions were made using DC magnetron sputtering, and optical, structural, electrochemical, electrical and photocatalytic studies of the films and particles were performed.

The various applications yield a variety of substrate properties, and how these substrate properties affect gold coalescence was studied by depositing gold on glass slides and on SnO2:In, ITO and TiO2 base layers.

Temperature also affects the gold coalescence. Therefore, gold was deposited on heated and non-heated substrates, where the latter were also post-heated, with a temperature range between 25ºC and 140ºC in both cases. Various temperatures were also used for manufacturing gold nanoparticles, and their effect as photocatalytic improvers was tested on WO3 films.

The optical properties of Au films on glass were determined by ellipsometry in the 0.25 – 2 µm range, and then a spectral density analysis was performed of the effective dielectric permittivity.

This work showed that thin gold films are excellent replacements for oxide-based transparent conductors in electrochromic devices. It was also shown that thin homogeneous gold films were better conductors when they were deposited on glass, compared to when they were deposited on oxide base layers, regardless of the optical, electrical and structural properties, or the doping concentration of the base layers.

The results also showed that thin gold films were durable at 76ºC, and hence hold for a typical window temperature of ~70ºC. For higher temperatures, gold deposition on heated and non-heated substrates resulted in a distinct difference in growth, and there was also a distinct difference between post-heated gold films produced at 25ºC, compared to when the films were deposited on heated substrates. In the latter case, an island structure was obtained at 140ºC.

Spectral density analysis gave spectral densities of similar shape for nanoparticles and continuous gold films, which is useful information for further investigations.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2012. , 100 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 950
Keyword [en]
green nanotechnology, transparent conductors, nanoparticles, gold coalescence, substrate effect, temperature effect
National Category
Nano Technology
Research subject
Physics
Identifiers
URN: urn:nbn:se:uu:diva-179173ISBN: 978-91-554-8420-0 (print)OAI: oai:DiVA.org:uu-179173DiVA: diva2:543574
Public defence
2012-09-21, Häggsalen, Ångström laboratoriet, Lägerhyddsvägen 1, Uppsala, 09:30 (English)
Opponent
Supervisors
Available from: 2012-08-30 Created: 2012-08-08 Last updated: 2013-01-22
List of papers
1. Au thin films deposited on SnO2:In, In2O3:Sn, TiO2 and glass by sputtering: Substrate effects of thin film growth
Open this publication in new window or tab >>Au thin films deposited on SnO2:In, In2O3:Sn, TiO2 and glass by sputtering: Substrate effects of thin film growth
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Thin Au films are promising transparent conductors with many potential application in green nanotechnology. These applications may require many different substrate materials, and hence a detailed understanding of the role of the substrate material on Au thin film growth is important. Such substrate effects have been studied in this work, where Au films ranging from island structures up to thin homogenous layers were deposited by DC magnetron sputtering onto glass substrates and onto SnO2:In, In2O3:Sn (ITO), and TiO2 layers on glass. Data were recorded by optical, electrical, structural and chemical analyses. We found a distinct difference in the Au growth depending on the properties of the substrates, and the results highlight the complexity of substrate impact on the growth. 

Keyword
Transparent conductors, Au thin films, Sputter deposition, Electron microscopy, Substrate effect
National Category
Other Physics Topics
Research subject
Physics
Identifiers
urn:nbn:se:uu:diva-179153 (URN)
Available from: 2012-08-08 Created: 2012-08-08 Last updated: 2012-08-31
2. Spectral density analysis of thin gold films: Thickness and structure dependence of the optical properties
Open this publication in new window or tab >>Spectral density analysis of thin gold films: Thickness and structure dependence of the optical properties
(English)Manuscript (preprint) (Other academic)
Keyword
Au thin films, Sputter deposition, Electron microscope, Image analyzing, Ellipsometry, Spectral density function.
National Category
Other Physics Topics
Research subject
Physics
Identifiers
urn:nbn:se:uu:diva-179159 (URN)
Available from: 2012-08-08 Created: 2012-08-08 Last updated: 2012-08-31
3. TiO2/Au/TiO2 Multilayer Thin Films: Novel Metal-Based Transparent Conductors for Electrochromic Devises
Open this publication in new window or tab >>TiO2/Au/TiO2 Multilayer Thin Films: Novel Metal-Based Transparent Conductors for Electrochromic Devises
2009 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 518, no 4, 1225-1229 p.Article in journal (Refereed) Published
Abstract [en]

Transparent conductors based on Au films, with thicknesses in the 2.6<d<9.8 nm range, were made by DC magnetron sputtering onto glass. The films went from an "island" structure at low thicknesses to a uniform structure at d>8 nm, as seen from electron microscopy, electrical resistance, and spectrophotometric transmittance and reflectance. Optical data for uniform films were given a consistent interpretation within the Drude model. Optimized TiO2/Au/TiO2 films, with a luminous transmittance of 80%, were found to have good electrochemical durability and may be useful for applications in electrochromic devices.

National Category
Engineering and Technology
Research subject
Solid State Physics
Identifiers
urn:nbn:se:uu:diva-122136 (URN)10.1016/j.tsf.2009.02.158 (DOI)000272733200046 ()
Available from: 2010-04-06 Created: 2010-04-06 Last updated: 2017-12-12Bibliographically approved
4. Au thin films deposited on SnO2:In and glass: Substrate effects on the optical and electrical properties
Open this publication in new window or tab >>Au thin films deposited on SnO2:In and glass: Substrate effects on the optical and electrical properties
Show others...
2011 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 519, no 6, 1930-1933 p.Article in journal (Refereed) Published
Abstract [en]

We report on a detailed study on the optical and electrical properties of Au films made by sputter deposition onto glass substrates with and without transparent and electrically conducting layers of SnO2:In. The Au films had thicknesses up to 10.7 nm and hence spanned the range for thin film growth from discrete islands, via large scale coalescence and formation of a meandering conducting network, to the formation of a more or less "holey" film. Scanning electron microscopy and atomic force microscopy demonstrated that the SnO2:In films were considerably rougher than the glass itself, and this roughness influenced the Au film formation so that large scale coalescence set in at a somewhat larger thickness for films on SnO2:In than on glass. Measurements of spectral optical transmittance and reflectance and of electrical resistance gave a fully consistent picture that could be reconciled with impeded Au film formation on the SnO2:In layer; this led to pronounced "plateaus" in the near infrared optical spectra for Au films on SnO2:In and a concomitant change from such two-layer films having a lower resistance than the single gold film at thicknesses below large scale coalescence to the opposite behavior for larger film thicknesses. Our work highlights the importance of the substrate roughness for transparent conductors comprising coinage metal films backed by wide band gap transparent conducting oxides.

Keyword
Transparent conductors, Gold films, Indium doped tin oxide, Sputter deposition, Optical properties, Electrical resistance, Thin film growth, Large scale coalescence
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Solid State Physics
Identifiers
urn:nbn:se:uu:diva-148464 (URN)10.1016/j.tsf.2010.09.048 (DOI)000287339000028 ()
Available from: 2011-03-08 Created: 2011-03-07 Last updated: 2017-12-11Bibliographically approved
5. Thin gold films on SnO2:In: Temperature-dependent effects on the optical properties
Open this publication in new window or tab >>Thin gold films on SnO2:In: Temperature-dependent effects on the optical properties
2012 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 520, no 9, 3688-3691 p.Article in journal (Refereed) Published
Abstract [en]

Gold films with thicknesses of 5 +/- 0.5 nm were sputter deposited onto SnO2:In-coated glass kept at different temperatures up to 140 degrees C, and similar films, deposited onto substrates at 25 degrees C, were annealing post treated at the same temperatures. Nanostructures and optical properties were recorded by scanning electron microscopy and spectrophotometry in the 0.3 to 2.5 mu m wavelength range, respectively. Annealing had a minor influence on the optical transmittance despite significant changes in the scale of the nanostructure, whereas deposition onto substrates heated to 140 degrees C yielded granular films with strong plasmon absorption of luminous radiation. These results are of considerable interest for optical devices with gold films prepared at elevated temperature or operating at such temperature.

Keyword
Gold film, Structural evolution, Optical properties, Transparent conductor, Energy efficiency
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Solid State Physics
Identifiers
urn:nbn:se:uu:diva-172847 (URN)10.1016/j.tsf.2012.01.016 (DOI)000301627100047 ()
Available from: 2012-04-17 Created: 2012-04-16 Last updated: 2017-12-07Bibliographically approved

Open Access in DiVA

fulltext(2989 kB)5702 downloads
File information
File name FULLTEXT01.pdfFile size 2989 kBChecksum SHA-512
05c38a5f79fdaa262ade4f49b382e26e4682ca4dc705f2dbc8de94423ff3740b6a131a6907ed0e6da5148d6be271150fde86131fea49e407ed5bcd6ec9796edd
Type fulltextMimetype application/pdf
Buy this publication >>

Authority records BETA

Lansåker, Pia

Search in DiVA

By author/editor
Lansåker, Pia
By organisation
Solid State Physics
Nano Technology

Search outside of DiVA

GoogleGoogle Scholar
Total: 5702 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 1623 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf