Spectroscopic evidence for trap-dominated magnetic field effects in organic semiconductors
2014 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 90, no 15, 155205Article in journal (Refereed) Published
Polaron traps are ubiquitous in organic semiconductors and recent evidence suggests they might be crucial for the large observed magnetic field effects (MFEs) in organic semiconductors. Here we measure MFEs in polymer thin-film devices with engineered, radiative trap sites in order to spectroscopically investigate the influence of the traps. Surprisingly, the luminescence at the trap sites and the polymer backbone is found to have an opposite response to a magnetic field. All our results are compatible with a mechanism in which spin mixing at the traps can create the large MFEs observed on the backbone. This scenario is quantitatively confirmed by numerical drift-diffusion modeling with magnetic-field-dependent exciton densities at the traps. These insights solve an outstanding controversy within the research field.
Place, publisher, year, edition, pages
American Physical Society , 2014. Vol. 90, no 15, 155205
Condensed Matter Physics
IdentifiersURN: urn:nbn:se:liu:diva-116204DOI: 10.1103/PhysRevB.90.155205ISI: 000344023900001OAI: oai:DiVA.org:liu-116204DiVA: diva2:797736
Funding Agencies|Dutch Technology Foundation (STW), Netherlands Organization for Scientific Research (NWO)2015-03-252015-03-252015-05-12Bibliographically approved