John W. Weigl

Charge Transfer Sensitization of Some Organic Photoconductors Based on Carbazole

Abstract The photoresponse of thin layers of vinyl carbazole (VK), dissolved in an acrylic binder, and of polyvinyl carbazole (PVK) was measured in a quasi-xerographic mode. Complexing with strong electron acceptors gives rise to visible charge transfer bands, which are found to be efficient at exciting photoresponse in this part of the spectrum. In the case of the binder layers, complexing greatly enhances UV response, as well. The observed photoresponse is tentatively accounted for by the photosensitized injection of carriers into the dielectric layer, rather than by bulk photoconductivity.

PHOTOSENSITIZATION OF CONDUCTION IN MOLECULAR SOLIDS

Abstract— The mechanism of spectral sensitization of conduction in molecular photoconductors has been investigated in systems in which sensitizer and photoconductor form separate layers. The efficiency of sensitization is strongly influenced by external fields, approaching 100 per cent at 106 V/cm in certain cases. The spectral response, efficiency, and field dependence are characteristic primarily of the sensitizer, while the transport characteristics are largely determined by the photoconductor.