This is a semiconductor device that directly converts “solar energy into electricity.” (IEA) It is one of the main processes solar panels use to produce electricity.

The term “photovoltaic” comes from the Greek φῶς (phōs) meaning “light”, and from “volt”, the unit of electromotive force, the volt, which in turn comes from the last name of the Italian physicist Alessandro Volta, inventor of the battery. (From Wikipedia).