Basic Information on Solar Panels and How They Work

Photovoltaic panels, or solar panels, were first built in 1954 by Bell Laboratories. At that time they were more of a curiosity than anything else and it was expensive to build them as each one was individually made by hand. NASA began using them in the 1960s to power systems on spacecraft. As the technology progressed and they were made oftener and oftener, the cost of making them decreased. During the energy crisis in the 70s photovoltaic panels began being used as an alternate electrical source for other applications as well. There are four basic parts to a solar cell. There is the surface anti-reflecting pane that protects the inside of it and allows the light to go through. The next layer is a contact that runs across the upper surface of the imbedded cells. The active layer, under the upper contact, is a semiconductor wafer specially treated to create an electrical field that is positive on one surface and negative on the other surface. Below that is the back contact, allowing a circuit to be connected to the entire cell. This cell is then hooked up with others to form a module and many modules are connected together to make the size array or panel desired. When sunlight streams down and passes through the surface anti-reflecting material it strikes the active layer that carries the electrical charge. As the proper wavelength of light passes through this, it knocks electrons loose, which become ‘excited’ and begin moving. These electrons all flow in one direction and by hooking a load to the upper and lower contacts, forming a circuit, they can be ‘captured’ and the energy put to use. By connecting the proper amount of modules you can get the desired amount of DC (Direct Current) needed. Commonly they are hooked up to power a 12 volt system like your car uses. Each of the active layers is designed to catch a certain bandwidth of light. Solar panels can be made more efficient by stacking modules that each utilise a progressively different light frequency until there is very little light escaping unused at the bottom.