How does a solar panel work?

A solar panel generates electricity from sunlight through the photovoltaic effect. Each panel is made of many solar cells, typically built from silicon, a semiconductor. The silicon is treated so that it has two layers with different electrical properties, creating an electric field at their junction. When sunlight, made of particles of energy called photons, strikes the cell, it transfers energy to electrons in the silicon and knocks some of them loose. The built-in electric field pushes these freed electrons to flow in one direction, producing a direct electric current. Metal contacts collect this current so it can power devices or be fed into the grid. Because solar panels produce direct current, an inverter is usually used to convert it into the alternating current used in homes. Solar power is a clean, renewable energy source that produces no emissions while operating.