The Photovoltaic Trick

Solar cells are made of silicon — the same element in sand and computer chips. The magic happens at the junction of two specially treated silicon layers.

• The top layer is doped with phosphorus, giving it extra electrons (n-type silicon)
• The bottom layer is doped with boron, creating electron "holes" (p-type silicon)
• Where they meet, a natural electric field forms — the p-n junction
• When a photon hits an electron in this zone, it knocks the electron free.