title: On the role of local charge carrier mobility in the charge separation mechanism of organic photovoltaics.
abstract: Although the charge separation (CS) and transport processes that compete with geminate and non-geminate recombination are commonly regarded as the governing factors of organic photovoltaic (OPV) efficiency, the details of the CS mechanism remain largely unexplored. Here we provide a systematic investigation on the role of local charge carrier mobility in bulk heterojunction films of ten different low-bandgap polymers and polythiophene analogues blended with methanofullerene (PCBM). By correlating with the OPV performances, we demonstrated that the local mobility of the blend measured by time-resolved microwave conductivity is more important for the OPV output than those of the pure polymers. Furthermore, the results revealed two separate trends for crystalline and semi-crystalline polymers. This work offers guidance in the design of high-performance organic solar cells.
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan. saeki@chem.eng.osaka-u.ac.jp seki@chem.eng.osaka-u.ac.jp.
authors.forename: Saya
authors.initials: S
authors.lastname: Yoshikawa
authors.forename: Akinori
authors.initials: A
authors.lastname: Saeki
authors.forename: Masahiko
authors.initials: M
authors.lastname: Saito
authors.forename: Itaru
authors.initials: I
authors.lastname: Osaka
authors.forename: Shu
authors.initials: S
authors.lastname: Seki