Photoinduced electron transfer from triplet states of phthalocyanines to fullerenes studied by transient absorption spectroscopies in visible and near-IR regions

Photoinduced electron transfer processes between C 60/ C 70 and phthalocyanines such as tetra-tert-butylphthalocyanine ( H 2 TBPc ) and its zinc derivative ( ZnTBPc ) in polar solvents have been studied by observing the transient absorption spectra in the visible and near-IR regions. Upon predominant excitation of TBPcs with a 670 nm laser pulse in polar solvents, growth of the transient absorption bands of [Formula: see text] and [Formula: see text] was observed, accompanied by a concurrent decay of the triplet states of TBPcs (3 TBPc *). Thus it is confirmed that electron transfer occurs via 3 TBPc * in polar solvents. The electron transfer rate constants and efficiencies of electron transfer via 3 ZnTBPc * are greater than those via 3 H 2 TBPc * owing to the electron ejection ability of 3 ZnTBPc *. Solvent effects on the forward and backward electron transfer processes have been evaluated.