Combined Sensitisation
of Benzaldehyde Diphenylhydrazones:
Effect of Hydrazone Structure on Sensitization
Efficiency
E.V.
3, Academichesky Ave., 634021, Tomsk, Russia
Abstract
Injection,
spectral and combined (injection-spectral) sensitisations
of several benzaldehyde diphenylhydrazones
have been studied using the layers of amorphous selenium and complex compounds based
on pyril dyes to broaden photosensitivity spectrum of
electrophotographic carrier and to study sensitisation mechanism. Two photogeneration
mechanisms for charge carriers have been shown to exist at a combined sensitisation, i.e. generation in the injection
layer followed by the injection into a transport layer and generation in a
transport layer on a dye. The excited dye molecules have been established to
create hole strapping sites in a transport layer: it is exhibited in a
different nature of photodischarge curves in
selenium- and dye-absorbing regions at the negative surface potential. The
effect of the substituent in a benzaldehyde
fragment on the efficiency of injection, spectral and combined sensitisations of benzaldehyde diphenylhydrazones has been studied. The ionization
potentials of hydrazones were determined by the two following methods:
according to the charge transfer band of hydrazone-chloranil
charge transfer complexes and by means of quantum-chemical calculations of hydrazone molecules to interpret the results obtained. In
the course of quantum-chemical calculations the conjugation character was also
determined in the molecules of benzaldehyde diphenylhydrazones.