Photoinduced electron transfer in solid C60 donor/acceptor complexes.

Light-induced ESR spectroscopy was used to study photoinduced electron transfer (PIET) in the crystals of the C-60 donor/acceptor complexes: TMPD .C-60 (1), LCV .C-60.C6H5Cl (2), and (BA)(2)C-60 (3). LESR signals from C-60(-.) with g=1.9984-1.9992 and DeltaH=3-6G (100K) for 1-3 as well as the LESR signal from TMPD+. for 1 were observed. The LESR signals have two components: a long-lived "persistent" component and a "prompt" one, which disappears immediately after light is off. All PIET processes are temperature activated with E-a=23, 43 and 49 meV for 2, 3, and 1, respectively. The temperature dependence of spin susceptibility in 1 can be described by the Bonner-Fisher model, while in 2 it corresponds to a paramagnetic behavior of isolated spins.