Photovoltaic solar panels are a somewhat more complex construction than solar thermal collectors used for solar heating.
Made from thinly-cut cells of silicon crystal, PV solar panels have positive and negative layers. That means one side of each cell has an abundance of electrons, while the other has a shortage of them.
This imbalance creates an electrical field in the cell, allowing the passing of electrons from the negative to the positive layer.
The sun's energy, which travels in photons, provides the catalyst for this movement. Absorbed by the PV solar panel, it passes its energy to atoms within the cell and kick starts the electron transfer.
In short, it is this movement of electrons which generates electricity for your home.
The most efficient (and most expensive) PV solar panels are cut from a single silicon crystal, while the more common polycrystalline PV panels are constructed from a number of crystals.
The latest type of PV solar panel is the 'amorphous' panel, cut so thin as to retain flexibility for easier setting. Currently, the efficiency of solar panels averages around 20% - but this is markedly higher than at the turn of the century, so it can be expected to increase again as technology improves.