In aromatic PI films, charge-transfer-complexes (CTCs) could be formed through imide units as electron acceptors and aromatic residues as electron donors. The charger transfer (CT) interactions of these CTCs cause aromatic PI films weak photoconduction in extrinsic process. Though such photoconductivity of classic PI, e.g. PMDA/ODA PI, for application to be applied in practical photoconductor device, however, a possibility is presented that highly photosensitive and environmentally resistant photoconductive polyimide should be realized through improving the photoconductivity with method of enhancing the formation of CTC and copolymerizing intrinsic chromophore in to backbone. In this review, the progress of CTC and photoconduction of polyimide are introduced. First, The formation and influencing factors of CTC, charge transfer of CTCs in polyimide are introduced mainly basing on discussing the observations of absorption and fluorescence behavior of polyimides as well as their model systems. Secondly, the photoconduction process and its dependence on CTCs in polyimide system are elicited from the reported measurements of photogenerated current and transient absorption properties. Thirdly, the approaches to practically photoconductive polyimides, including aggregation structure control, preparation of super thin film, and copolymerizing the moieties of porphyrin, phthalocyanine and perpylene into polymer backbones, are circumstantiated at length. It is demonstrated that polyimides should be developed into potential photoconductive materials in the applications of photovoltaic and xerographic processes.
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