Extremely strong room-temperature transient photocurrent-detected magnetic resonance in organic devices

TitleExtremely strong room-temperature transient photocurrent-detected magnetic resonance in organic devices
Publication TypeJournal Article
Year of Publication2012
AuthorsChen Y, Liu R, Cai M, Shinar R, Shinar J
Journal TitlePhysical Review B
Volume86
Pages235442
Date Published12
Type of ArticleArticle
ISBN Number1098-0121
Accession NumberWOS:000312832600016
Keywordsbipolarons, degradation, ELECTROLUMINESCENCE, electron, films, LIGHT-EMITTING-DIODES, photooxidation, polaron, POLYMERS, silicon
Abstract

An extremely strong room-temperature photocurrent- (PC- or I-PC-) detected magnetic resonance (PCDMR) that elucidates transport and trapping phenomena in organic devices, in particular solar cells, is described. When monitoring the transient PCDMR in indium tin oxide (ITO)/poly(2-methoxy-5-(2'-ethyl)-hexoxy-1,4-phenylenevinylene) (MEH-PPV)/Al devices, where the MEH-PPV film was baked overnight at 100 degrees C in O-2, it is observed that | Delta I-PC/I-PC| peaks at values >> 1, where Delta I-PC is the change in I-PC induced by magnetic resonance conditions. Importantly, Delta I-PC and I-PC are of different origin. The mechanism most likely responsible for this effect is the spin-dependent formation of spinless bipolarons adjacent to negatively charged deep traps, apparently induced in particular by oxygen centers, to form trions. DOI: 10.1103/PhysRevB.86.235442

URL<Go to ISI>://WOS:000312832600016
DOI10.1103/PhysRevB.86.235442