Doped Silicon – The Hard Cell
A solar panel is a collection of solar cells connected within a frame. The cells make electricity for homes and businesses world wide.
We call solar panels photovoltaic (PV) modules. Photo is Latin for light and voltaic refers to electricity: electricity from light. A collection of modules form systems, which are known as solar arrays.
Since all energy on the planet is a result of the largest local nuclear fusion reactor (The Sun, silly!), we have always used solar energy. But solar electricity, as we know it, was born in Bell Labs in 1954 when Daryl Chapin, Calvin Fuller, and Gerald Pearson develop the first silicon photovoltaic cell.
The most popular solar cells are still made from silicon (around 90% in 2011). Why? Silica (silicon) is one of the most abundant resources on the planet. Note: since 1954, the conversion efficiency has more than quadrupled. Conversion efficiency is how we measure the difference between energy available and potential electricity we can produce from it. Another solar module commonly used are called Copper Indium Gallium Selenide (CIGS): these result in the more flexible thin film PV, but they are not as good at converting energy into electricity so they are not as popular as rigid silicon.
So how do silicon solar cells generate electricity?
When photons (solar energy) smash in to the silicon cell, electrons in the modified silicon atoms (also called doped silicon) can break their bonds in the crystal. The freed electrons search like mad for a hole to fill. When they find one, they release all that wonderful potential energy. Freed electrons produce electric current. Since a path is built in to the modules, the energy is directed for our use.