Transient absorption study on photoinduced electron transfer between C 60 and poly( N-vinylcarbazole) in polar solvent

Abstract

Photoinduced electron transfer reactions between C 60 and poly( N-vinylcarbazole) (PVCz) in polar benzonitrile solution have been investigated by observing the transient absorption bands in the visible and near-ir regions. When C 60 was photoexcited, the electron transfer reaction occurred via both 3 C 60 ∗ and 1 C 60 ∗. In the case of the reaction via 3 C 60 ∗, electron transfer rate constant was 5.1×10 6 M −1 s −1, which is larger than that of the reaction between 3 C 60 ∗ and EtCz by a factor of 7.5, indicating a stabilization of cation radical of carbazole in PVCz. Electron transfer reactions via 1 C 60 ∗ proceeded at the diffusion-controlled rate, while the quantum yield for electron transfer is not high. When PVCz was photoexcited, direct photo-ejection occurred from PVCz yielding PVCz + and solvated electron, in which the latter was captured by C 60. Electron transfer from 3PVCz ∗ to C 60 was also pointed out as a charge generation mechanism.