Solar Energy : The Alternative Energy Sources

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Photovoltaic Technologies With the evolution of society, the necessity of alternative energy sources, that suit in what sustainable development requires is more evident throughout the years. Since the reduction of the emission of gases that cause the greenhouse effect, for example, is an important factor. The sun is the planet’s primary energy. It is responsible for practically all of the observable natural processes. Thus, nowadays, technologies that have the sun as a source have been considered, studied and utilized. The photovoltaic technologies are an example of how it is practicable to obtain energy from the sun. These TECHNOLOGIES have been developed throughout the years and it is one of the main hopes of clean and renewable energy…show more content…
They are electric devices that are capable of converting the light directly into electricity by the photovoltaic effect. This effect was discovered by the french physicist Alexandre Edmond Becquerel in 1839. He observed that if he plunged metallic plates (platinum or silver) in a electrolyte they would develop a potential difference when exposed to light. So, the effect consists, basically, on the appearance of an electric voltage in a semiconductor material when it is exposed to visible light. There solar cells are divided in three categories: the first, second and third generation. The first generation cells were the first ones to be developed and they were consisted of systems that occupied a large area, in spite of the high quality. The type of technology used in these solar cells required the use of a large amount of energy for the transformation of solar energy into electrical, what implied in high costs. The cell is composed of a purified silicon wafer doped, at the same time, with boron and phosphorus. The phosphorus part doped, is exposed to the sun. The part doped with boron is at the bottom of the cell, and it is greater than the other one. Front and rear contacts are placed, and the front contacts on the phosphorus part, causes shadow and reflection, decreasing the efficiency of the cell. It would be theoretically possible to reduce the losses by reflection, decreasing the amount of front contacts, but
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