The kinetics of photoelectric processes near interfaces of C60/liquid crystals

The interface between vacuum deposited C60 fullerene films and layers of mimetic liquid crystals (LC), such as pentylcyanobiphenyl (5??) or the BL055 mixture has been studied. In order to understand the processes of barrier formation at the C60 /LC interface, the kinetics of the dark current, short-circuit photocurrent and photo voltage caused by short pulses of light (~60 sec, hv = 1.88 eV) were investigated. Initial barrier height at the ?60 /LC interface and its increase caused by ion diffusion to electrodes under the action of an internal electric field or light are determined. A fast component of the short-circuit photocurrent and photo voltage was observed. This component was probably due to the presence of a partly filled acceptor-like deep electron level associated with an interaction between C60 molecules and oxygen. The occupancy of the local states depends on molecular interactions at the interface. Their effect on the processes of ionic polarization and depolarization is discussed.