How Photovoltaics Work
To understand how photovoltaics work, you first need to understand a bit about solar energy. Basically, sunlight is loaded with photons. Think of these as little packages of solar energy. Photovoltaics are panels that turn this sun power into electricity.
They are made from silicon. The silicon is doped with small amounts of boron and phosphorous. The boron doped silicon is P-type, or positively charged silicon. The phosphorous silicon is N-type, or negatively charged silicon. The connection of these two types of silicon is called the p-n junction.
When the photons from sunlight hit a silicon molecule, it knocks loose an electron. This electron hits another silicon molecule, shunting another electron out of it's molecule.
This starts a chain reaction, rather like one domino striking another, which knocks over another, and another....
The final result of this chain reaction is what is known as an flow of electrons, or an electrical current. This flow of electrons takes the path of least resistance, namely a metal circuit wire, or conductor, embedded connected to the silicon panels.
This solar electrical current then flows through the circuits to loads. These are demands for energy in your house. These loads could be lights, fridges - whatever you have on at the time.
This is a simple explanation of the photovoltaic effect (how solar panels generate electricity.) For a more detailed description, you might want to check out Wikipedia.
Another thing to note is that scientists are developing solar panels that generate solar power without using silicon. These plant dye solar panels are cheaper to produce, and have the potential to be very efficient, especially in low light conditions. (Rather like plants.)