When sunlight strikes a solar panel, it generates electricity through the photovoltaic effect. Here is how that works, one layer at a time.
Semiconductors and electrons
Inside each solar cell is a semiconductor — most commonly silicon — with carefully arranged electrical properties. In a semiconductor, electrons normally stay bound within the material. But the energy carried by a photon of sunlight can knock an electron loose, leaving a moving charge in its place. This is the heart of the photovoltaic effect: light energy lifting electrons into motion.
An electric field inside the cell
Loose electrons alone would wander randomly. Solar cells add a built-in electric field by treating the silicon so that one side of the cell has a slight excess of one type of charge carrier and the other side the opposite. The junction between those layers pushes freed electrons in a consistent direction — and a directed flow of charge is an electric current.
From cells to modules to arrays
A single cell produces only a small voltage, so manufacturers wire dozens of cells together into a module — the familiar panel — and wire modules together into an array. Connected cells add their voltages along the string, producing the direct current (DC) that leaves the array through its cabling.
DC to AC
Solar cells produce direct current, which flows in one direction. Homes and businesses use alternating current (AC), which reverses direction many times per second. The inverter performs that conversion, reshaping the DC into AC that matches the grid's rhythm.
For the hardware that carries out each step, continue to System Components.