Solar panels have been an icon of renewable energies for a very long time but have failed to catch on until recent years. There are many different kinds of solar cells because of their internal makeup. If we could catch 100% of the photons arriving on earth in one square meter, it would be about one kilowatt or 1,000 watts of electricity! This is exciting because there would be little need for other sources of power production.
How Solar Panels Work
Solar panels work by having something called a p/n junction. The p/n junction is a necessity in most electronics of our age and we certainly wouldn’t have advanced this far without it. Valence electrons are the outer most electrons available for bonding. An atom containing 1-3 valence electrons are good conductors, while an atom containing 5-8 valence electrons is a good insulator. However, 4 valence electrons means that it is a semi-conductor. Semi-conductors are neither good conductors nor good insulators. If a silicon has a perfect balance of 14 electrons and 14 protons meaning it has no charge. Silicon has exactly four valence electrons.
Valence electrons are can be made to bond with other elements. The silicon atom has a crystalline structure. It bonds with four other atoms at once, we call this covalent bonding. We can add different atoms or dope the silicon to form pentivalent and trivalent bonds. This is mostly done with phosphorus and boron.When adding different elements together it is not longer called an element but a molecule. Penti meaning five bonds and tri meaning three, both of these bonds create the p/n junction. The p-type material is now a negative ion because it has gained an electron. The n-type material is a positive ion because it lost an electron. There is a difference of potential in these two materials which can cause electrons to flow if they are agitated in the correct way. It turns out sunlight is all we need once we form the p/n junction. When made to collect light, we call this a solar panel.
Why Solar Panels are Important
Solar panels can lead the way in renewable energy technologies. Solar panels will produce electricity as long as light is available, which means even on cloudy days they can still function. They can be retrofitted onto almost any building. Most solar panels are built to withstand golf ball sized hail. The price of solar panels is becoming cheaper yearly. They are more readily available and with higher efficiency than ever before.
Feature Image: Solar panels. Image via Flickr Creative Commons, University of Salford.