Photoelectron spectroscopy of the contact between the cathode and the active layers in plastic solar cells: the role of LiF
2005 (English)In: Japanese Journal of Applied Physics, ISSN 0021-4922, E-ISSN 1347-4065, Vol. 44, no 6A, 3695-3701 p.Article in journal (Refereed) Published
The surfaces and electrode interfaces of a polymer blend used in prototype solar cells have been characterized with photoelectron spectroscopy. The polymer blend in question is a 1:4 mixture of APFO-3:PCBM. Based on surface analysis of the pristine film we can conclude that the surface of the blend is a 1:1 mixture of APFO-3 and PCBM. The electrode systems studied are the widely used Al and Al/LiF contacts. LiF prevents formation at the Al/organic interface of Al-organic complexes that destroy the π-conjugation. In addition to this, there are two other beneficial, thickness dependent, effects. Decomposition of LiF occurs for thin enough layers in which the LiF species are in contact with both the organic film and the Al atoms, which creates a low workfunction contact. For thicker (multi)layers, the dipole formed at the LiF/organic interface is retained as no decomposition of the LiF occurs upon Al deposition.
Place, publisher, year, edition, pages
2005. Vol. 44, no 6A, 3695-3701 p.
IdentifiersURN: urn:nbn:se:liu:diva-30346DOI: 10.1143/JJAP.44.3695Local ID: 15883OAI: oai:DiVA.org:liu-30346DiVA: diva2:251168