[8][9] When a photoconductive material is connected as part of a circuit, it functions as a resistor whose resistance depends on the light intensity.
The most common application of photoresistors is as photodetectors, i.e. devices that measure light intensity.
[12] One prominent example is hydrogenated amorphous silicon (a-Si:H) in which a metastable reduction in photoconductivity is observable[13] (see Staebler–Wronski effect).
[14] The frequency-driven bulk-to-surface transition of conductivity is expected to be a generic character of semiconductor nanostructures with the large surface-to-volume ratio.
In this material a light induced magnetization melting was also demonstrated[20] thus could be used in magneto optical devices and data storage.