Solar_Sells

Solar Cells Solar cells are also known as photovoltaic cells. It is an electrical device that changes the energy of light to electricity by the photovoltaic effect. When it’s exposed to light, it can make an electric current without it having to be attached to any external voltage source. The first solar cell was built in 1883 by Charles Fritts but it was only 1% efficient. In 1888 the Russian physicist, Aleksander Stoletov built the first solar cell using the photoelectric effect. Solar cells are often electrically connected and encapsulated as a module, which normally have a sheet of glass on the front side. Having it like this allows light to pass but it also protects the semiconductor wafers. The cells are normally used in series. which creates an addictive voltage. If you use it with parallel it will hold a higher current. There are three steps on how the solar cell works. First step, photons, in the sunlight hit the solar panel and is absorbed by semiconducting materials. Second step, electrons are knocked loose from their atoms, causing an electric potential difference. Current starts flowing through the material to cancel the potential and this electricity is captured. Due to the special composition of solar cells, the electrons are only allowed to move in a single direction. Last step, selections of solar cells convert solar energy into a usable amount of direct current electricity. When speaking on the efficiency, it is broken down into reflectance efficiency, thermodynamic efficiency, charge carrier separation efficiency and conductive efficiency. A solar cell usually has a voltage dependent efficiency curve, temperature coefficients, and shadow angles. The materials used to make one are: monocrystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride, and copper indium selenide/sulfide. Many are made from bulk materials. Other materials are made as thin-films layers, organic dyes, and organic polymers. Since solar cells are semiconductor devices, they share the same processing and manufacturing techniques like computers and memory chips, other semiconductor devices. There are three research groups on this topic. The first one is trying to make solar cells cheaper and more efficient to effectively compete with other energy sources. The second one is trying to develop new technologies based on new solar cell architectural designs. And the last one has to do with developing new materials to serve as light absorbers and charge carriers.