Investigation on the photoconductive composites: TiOPc with various AZOs

The relationship between photoconductivity and content of azo has been studied in double-layered photoreceptor devices where azo/titanium oxide phthalocyanine (TiOPc) composites were used as the charge generation materials (CGMs) and N,N′-diethyl-p-phenyl aldehyde biphenyl hydrazone (DENH) served as the charge transporting material (CTM). Composites of 3,3′-dichloro-4,4′-bis(1″-azo-2″-hydroxy-3″-naphthoyl-o-chloroanide) biphenyl (DBCL) and TiOPc change photosensitivity with the content of DBCL, and two maximums were observed at 5 and 60% (by weight), respectively. Composites of 4,4′-bis (1″-azo-2″-hydroxy-3″-naphthoyl-o-chloroanide)biphenyl ether (DBO) and TiOPc show two maximums at 25 and 68%, respectively, while two maximums at 8 and 70% were recorded for composites of TiOPc with 4,4′-bis(1″-azo-2″-hydroxy-3″-naphthoyl-o-chloroanide) biphenyl (AZO-AS). Results from ESR measurements indicate that there exists a charge transfer from azos to TiOPc. Different contents of TiOPc change the degree of the charge transfer, resulting in various xerographic properties of the composites.