Solar Photovoltaic Cells Essay

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Solar Photovoltaic Cells Solar energy is a general term referring to any process that turns sunlight into energy. Two common forms of solar energy are used today: Solar photovoltaic cells and solar thermal technology. Solar thermal technology uses the heat generated from sunlight to create energy. Most commonly, this can be used to heat water for a house or other projects. Or, with increasing complexity, it can turn the heat into electricity. Unfortunately, much of this technology is too expensive and complex to be practical in the United States on any large scale. However, solar photovoltaic cells are a far more promising technology. They provide a simple way of turning light directly into energy. This paper will examine how…show more content…
A monocrystalline semiconductor is much like the ideal type described above. It has a pure p type crystal placed on a pure n type semiconductor crystal. This type of cell is the most efficient in terms of turning energy into electricity. But, it is expensive to manufacture because it is costly to produce large crystals of semiconductor material. A far more cost effective material to produce is polycrystalline cells. These consist of small grains of crystals randomly oriented to each other. Because the smaller crystals, much easier to manufacture, are simply placed together it is much cheaper. However, energy is lost as electrons must maneuver between the different crystals. This form of cells results in a lower efficiency. However, because it is the most economically efficient, it is used today. Another factor important in producing photovoltaic cells is the material used for the semi-conductor. By far the most common material used today is silicon. It is the second most abundant element in the earth’s crust, allowing for an almost limitless supply. Additionally, the energy required to free an electron from a silicon atom is convenient. It is positioned around the infer-red frequency of light allowing any light with energy greater than that to free electrons. Thus, all light in the visible and ultra-violet sphere will free electrons and create electricity. However, any energy of light above that required to free the electrons is
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