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A method, which makes use of difference of absorption in different stages of excitation process, is introduced to get more information about optical stimulated luminescence (OSL) properties of electron trapping materials (ETM). Absorption spectra of excited ETM contain all absorption of various traps (defects) together. So, the difference between absorption spectra before and after excitation (differential absorption) not only acts as the same as stimulation spectra, but also provides more information, such as holes stimulation, total volume of optical storage, etc. This method is helpful in studying OSL properties.

Photoconductive devices with organic (polyvinylcarbazole-PVK)/inorganic (zinc-sulfide--ZnS) thin-film heteropairing were fabricated. In external field, the excitation profile of the steady-state photoconductivity and the primary photoexcitation process of hybrid devices were presented and discussed. Comparison of photoconductivity of the devices and absorption spectra of PVK and ZnS implied that both layers absorption contributes to the photocurrent, but the effective part is at the interface of PVK and ZnS. The dependence of maximum photocurrent on the applied voltage and the dark and illuminated current spectra indicates the ultrafast charge transfer at the interface.