Zum Mechanismus der organischen Photoleiter

Abstract

The photoelectric behaviour of organic photoconductors can be explained by the cooperation of generation, transport and recombination of charge carriers.

The generation of electrons and holes may be the result of different processes such as intrinsic excitation, excitation of impurities, photoinjection from electrodes or ionisation of excitons. Theoretical considerations and experimental results indicates, moreover, that the transport of electronic charge carriers through the organic solid can be described in many cases by the rules of the band model. The recombination of electrons and holes must be considered as a rather complicated process depending, on among other factors, the densities and capture cross sections of defects (traps, recombination states) which are located in the bulk or at the surface of the solid.

It must be stressed that these different processes lead to an understanding of the relationships which are characteristic for organic photoconductors: An explanation can for instance be given for the dependence of photocurrents on the exciting wavelengths, doping-effects, n- and p-type of photoconductors, kinetic relationships and the influence of light intensity and temperature on photocurrents.