What happens to photoconductive material when light shines on it?

Photoconductive materials, such as cadmium sulfide, absorb photons when exposed to light. This absorption excites electrons, moving them into the material's conduction band and significantly increasing the number of free charge carriers. Because there are more free charge carriers available, the material's ability to conduct electricity improves. Therefore, its electrical resistance decreases. Distractors claiming that resistance increases or focusing on reflectivity are incorrect, as the defining characteristic of a photoconductive material is its enhanced electrical conduction in the presence of light.