The impact of driving force on electron transfer rates in photovoltaic donor-acceptor blends

Alexander J Ward; Arvydas Ruseckas; Mohanad Mousa Kareem; Bernd Ebenhoch; Luis A Serrano; Manal Al-Eid; Brian Fitzpatrick; Vincent M Rotello; Graeme Cooke; Ifor D W Samuel

doi:10.1002/adma.201405623

The impact of driving force on electron transfer rates in photovoltaic donor-acceptor blends

Adv Mater. 2015 Apr 17;27(15):2496-500. doi: 10.1002/adma.201405623. Epub 2015 Mar 10.

Authors

Alexander J Ward¹, Arvydas Ruseckas, Mohanad Mousa Kareem, Bernd Ebenhoch, Luis A Serrano, Manal Al-Eid, Brian Fitzpatrick, Vincent M Rotello, Graeme Cooke, Ifor D W Samuel

Affiliation

¹ Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife, KY16 9SS, UK.

PMID: 25759321
DOI: 10.1002/adma.201405623

Abstract

The effect of acceptor energy level on electron transfer rate in blends of the polymer solar-cell material poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]] (PTB7) is studied using time-resolved fluorescence. Fast electron transfer in less than 2 ps is observed for a driving force between 0.2 and 0.6 eV and the electron transfer is slower outside this range. This dependence is described by Marcus theory with a reorganization energy of ≈0.4 eV.

Keywords: PTB7; charge generation; excitonic solar cells; reorganization energy.