Transient absorption study on photoinduced electron transfer between C60 and poly(N-vinylcarbazole) in polar solvent

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 C-3(60)* and C-1(60)*. in the case of the reaction via C-3(60)*, electron transfer rate constant was 5.1 x 10(6) M-1 s(-1), which is larger than that of the reaction between C-3(60)* and EtCz by a factor of 7.5, indicating a stabilization of cation radical of carbazole in PVCz. Electron transfer reactions via C-1(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 (3)PVCz* to C-60 was also pointed out as a charge generation mechanism. (C) 2000 Elsevier Science Ltd. All rights reserved.