Photoinduced electron transfer between metal octaethylporphyrins and fullerenes (C60/C70) studied by laser flash photolysis: electron-mediating and hole-shifting cycles

摘要: Electron transfer (ET) processes of fullerenes (C60/C70) with metal octaethylporphyrins (MOEP) in a polar solvent have been investigated by nanosecond laser photolysis technique the visible/near-IR regions. By selective excitation C60/C70 using OPO light it has proved that electron takes place from ground states MOEP to triplet excited 3C60*/3C70*. via3MOEP* were also confirmed. In nonpolar toluene lifetimes 3C60*/3C70* decreased presence without evidence for and/or energy processes. On adding benzonitrile ion-radical formation was increased, suggesting that exciplexes 3[MOEP(δ+)—C60(δ−)/C70(δ−)]* would be dominant prior ion-pair less-polar solvent. addition viologen dication anion radicals transfers yielding radical cation. system MOEP–C60/C70–aromatic amine (DTQH), as second donor having lower oxidation potential than MOEP, hole shift cation aromatic observed. These observations photosensitized electron-transfer/electron-mediating and electron-transfer/hole-shift cycles confirmed transient absorption spectral method.