Role of coherence and delocalization in photo-induced electron transfer at organic interfaces
2016 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, no 32914Article in journal (Refereed) Published
Photo-induced charge transfer at molecular heterojunctions has gained particular interest due to the development of organic solar cells (OSC) based on blends of electron donating and accepting materials. While charge transfer between donor and acceptor molecules can be described by Marcus theory, additional carrier delocalization and coherent propagation might play the dominant role. Here, we describe ultrafast charge separation at the interface of a conjugated polymer and an aggregate of the fullerene derivative PCBM using the stochastic Schrodinger equation (SSE) and reveal the complex time evolution of electron transfer, mediated by electronic coherence and delocalization. By fitting the model to ultrafast charge separation experiments, we estimate the extent of electron delocalization and establish the transition from coherent electron propagation to incoherent hopping. Our results indicate that even a relatively weak coupling between PCBM molecules is sufficient to facilitate electron delocalization and efficient charge separation at organic interfaces.
Place, publisher, year, edition, pages
NATURE PUBLISHING GROUP , 2016. Vol. 6, no 32914
IdentifiersURN: urn:nbn:se:liu:diva-131663DOI: 10.1038/srep32914ISI: 000382648800001PubMedID: 27605035OAI: oai:DiVA.org:liu-131663DiVA: diva2:1014943
Funding Agencies|Research Council of Lithuania [MIP-090/2015, MIP-085/2015]; Swedish Science Council; Knut and Alice Wallenberg foundation through a Wallenberg Scholar grant2016-10-032016-09-302016-11-02