P-I-N LIKE BEHAVIOR IN 3-LAYERED ORGANIC SOLAR-CELLS HAVING A CO-DEPOSITED INTERLAYER OF PIGMENTS

Three-layered organic solar cells, having a sandwiched interlayer of co-deposited p-type phthalocyanine (Pc) pigments and n-type perylene derivative (PTC) pigments, exhibited photocurrent enhancement when compared with two-layered cells without the interlayer. A large number of Pc/PTC molecular contacts within the interlayer serve as active sites for effective charge carrier photogeneration. The photovoltaic characteristics of the three-layered configuration suggest the formation of a p-i-n like structure, in which the built-in potential produced by Fermi level differences in the respective pigment layers is mainly distributed across the co-deposited interlayer. Inorganic semiconductor films are also shown to be applicable to the present p-i-n cell structure as an n layer to obtain larger photovoltages.