Surface photovoltaic properties of AlClPc/Me-PTC composite films

Abstract The surface electronic properties of chloro-aluminum phthalocyanine (AlClPc)/ N , N′ ’-dimethylperylene-3,4,9,10-bis(dicarboximide) (Me-PTC) composites were investigated by surface photovoltage spectrum (SPS) and field-induced SPS (FISPS). In near infrared region, the composites showed evident surface photovoltaic responses, and the polarity of these responses symmetrically changed according to the external field. These results indicated the existence of local states in the composite thin films. We ascribed the local states to the photo-induced electron transfer from p-type AlClPc to n-type Me-PTC molecules. In the spectral region from 400–550 nm, an unusual polarity inversion was found with respect to the composite of 20 wt.% Me-PTC, which was associated with the energy transfer between Me-PTC and AlClPc molecules.