Solar Photovaltaic

The photovoltaic effect is the creation of an electric current in a solid as a result of the absorption of light – it was discovered almost 170 years ago. Solar photovoltaic cells consist of two extremely thin semiconductor layers of no more than 0.3 mm thickness altogether (Figure15). These are differently “contaminated” with atoms of various other elements: in one layer, the so-called p-type layer, this causes a linkage to be free which can be occupied by the electron; in the other layer, the n-type layer, there is an extra electron which is not used for the linkage between the silicon atoms. It can be released with little additional energy, and then moves freely. As a result, an electrical field builds up in the semiconductor at the interface between the two layers, which ensures that the electrons which have been rendered energetically freely mobile by the incident sunlight now move outward through the electrical circuit. That makes it possible to produce electrical energy with the help of the energy of incident light. The fascinating thing about photovoltaics facilities is that they have no moving parts, make no noise, and are actually not subject to any wear at all.

The preferred material is silicon in various forms: as high-quality monocrystalline silicon, as multicrystalline silicon, or as amorphous silicon. Other semiconductor compounds are possible, in addition to silicon, including gallium arsenide (Gas), copper indium diselenite (CIS), and some others; some have already secured their share of the market.

However, these solar photovoltaic modules are a little thicker and heavier than one would expect considering the thickness of the silicon layers of only 0.3 mm. They have to be held in a fixed shape, the electrical energy is tapped by means of contact plates and fingers, and ultimately, the whole thing must be protected by being embedded mechanically between glass plates. Another product is photovoltaic mats, also based on amorphous silicon, which have a somewhat thicker synthetic material on the back and are protected mechanically on the front by a thin permeable plastic layer. The technological development is very far advanced, and is in effect a mature system, but it is far from its goal as yet. Find out more photovoltaic systems.
Useful information Solar photovoltaic cells:
http://ezinearticles.com/?How-Crystalline-Solar-Photovoltaic-Cells-Work&id=2768475

Useful information solar photovoltaic:
http://www.greenearth4energy.com/solar_photovoltaic.html

Useful information photovoltaic systems:
http://www.greenearth4energy.com/photovoltaic_systems.html