MOLECULAR AGGREGATE FORMATION AND MICROPHASE SEGREGATION EFFECTS ON THE PHOTOELECTRICAL AND PHOTOVOLTAIC PROPERTIES OF POLYIMIDE-PERYLENEDIIMIDE COMPOSITE FILMS

摘要

The strong increase of electrophotographic sensitivity, charge carrier photo-generation quantum yield and improved photo voltaic characteristics (sandwich cells with ITO, Al electrodes) are found for films of photoconductive soluble polyimides based on doubled triphenylamine heavily doped by the soluble perylenediimides (with content up to 50-60 percent wt). It is shown that the effect is due to perylenediimide aggregates of some tens nanometers size which are formed during the film casting at high solvent evaporation rate. The further increase of photoelectric and photovoltaic parameters is achieved by using the films of polymer blends of polyimides with polyetherimides (Ultem-1000 type) also doped with soluble perylenediimides. In this case the effect is due to microphase segregation in doped polymer blend films caused by the partial incompatibility of polymers, that results in the formation of microregions with n- and p-types of photoconductivity contacting with each other and possible appearance of p-n bulk microheterojunctions.