photoleitenden

Photoleitenden, or photoconductive materials, are substances whose electrical conductivity increases when they are exposed to light. The phenomenon, photoconductivity, arises when photons are absorbed and generate mobile charge carriers such as electrons and holes. In the presence of an electric field, these carriers contribute to electric current, lowering the material’s resistance. Some photoleitende materials can also display persistent photoconductivity, where the enhanced conductivity remains after illumination has stopped due to traps in the lattice that release carriers slowly.

Mechanisms and characteristics vary by material. In inorganic semiconductors the effect typically follows band-structure logic: light with energy above the bandgap creates electron-hole pairs, increasing conductivity. In some cases, traps and defects affect the magnitude and duration of the response, leading to slower decay or memory-like behavior. Photoconductivity can depend on wavelength, intensity, temperature, and the presence of dopants or interfaces with other materials.

Applications of photoleitende materials include imaging and sensing. In xerography, photoconductive layers on photoreceptor drums store electrostatic patterns that are later developed into images. In photodetectors and imaging arrays, they convert light into an electrical signal. They are also found in certain optoelectronic devices, such as phototransistors and light-activated switches, where light controls current flow.

Common materials encompass inorganic semiconductors such as selenium, cadmium sulfide (CdS), cadmium sulfide/cadmium selenide blends, zinc oxide (ZnO), and amorphous silicon. Organic and hybrid materials, including various polymeric and perovskite systems, also exhibit photoconductivity and are explored for flexible or large-area light-sensing applications.