A solar cell, or photovoltaic cell, converts light directly into electricity. Most are made of silicon, a semiconductor that conducts electricity better than an insulator but not as well as a metal.
The typical cell is a large-area p-n junction: two layers of silicon treated so one has extra electrons and the other has gaps for them. When light hits the junction, it frees electrons that flow as current. A single cell produces only about half a volt, so cells are wired together into panels.
Newer cells use materials such as solar inks, dyes and conductive plastics, but silicon remains the workhorse of the industry thanks to its efficiency and durability.
Related solution: Solar energy