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

Photoinduced electron transfer reactions between C₆₀ 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 C₆₀ was photoexcited, the electron transfer reaction occurred via both ³C₆₀/* and ¹C₆₀/*. In the case of the reaction via ³C₆₀/*, electron transfer rate constant was 5.1 x 10⁶ M^-1 s^-1, which is larger than that of the reaction between ³C₆₀/* and EtCz by a factor of 7.5, indicating a stabilization of cation radical of carbazole in PVCz. Electron transfer reactions via ¹C₆₀/* 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 C₆₀. Electron transfer from ³PVCz* to C₆₀ was also pointed out as a charge generation mechanism.