Abstract
The charge generation mechanism in organic photovoltaics is a fundamental yet heavily debated issue. All the generated charges recombine at the open-circuit voltage (), so that investigation of recombined charges at provides a unique approach to understanding charge generation. At low temperatures, we observe a decrease of , which is attributed to reduced charge separation. Comparison between benchmark polymer:fullerene and polymer:polymer blends highlights the critical role of charge delocalization in charge separation and emphasizes the importance of entropy in charge generation.
- Received 26 November 2014
DOI:https://doi.org/10.1103/PhysRevLett.114.128701
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