Role of Thick-Lithium Fluoride Layer in Energy Level Alignment at Organic/Metal Interface: Unifying Effect on High Metallic Work Functions
2015 (English)In: ADVANCED MATERIALS INTERFACES, ISSN 2196-7350, Vol. 2, no 4, 1400527- p.Article in journal (Refereed) Published
The function of approximate to 3-nm thick lithium fluoride (LiF) buffer layers in combination with high work function metal contacts such as coinage metals and ferromagnetic metals for use in organic electronics and spintronics is investigated. The energy level alignment at the organic/LiF/metal interface is systematically studied using photoelectron spectroscopy and the integer charge transfer model. The thick-LiF buffer layer is found to pin the Fermi level to approximate to 3.8 eV, regardless of the work function of the initial metal due to energy level bending in the LiF layer caused by depletion of defect states. At 3-nm thickness, the LiF buffer layer provides full coverage, and the organic semiconductor adlayers are found to physisorb with the consequence that the energy level alignment at the organic/LiF interface follows the integer charge transfer models predictions.
Place, publisher, year, edition, pages
Wiley: 12 months , 2015. Vol. 2, no 4, 1400527- p.
IdentifiersURN: urn:nbn:se:liu:diva-117235DOI: 10.1002/admi.201400527ISI: 000350756300005OAI: oai:DiVA.org:liu-117235DiVA: diva2:807097
Funding Agencies|European Commission [NMP3-SL-2011-263104]; SUNFLOWER (FP7-ICT-7) ; Swedish Research Council [2013-4022]; Goran Gustafsson Foundation for Research in Natural Sciences and Medicine2015-04-222015-04-212015-06-03