PHOTOVOLTAICS
... layer of gold. Fritts's devices were very inefficient converters of energy; they transformed less than 1 percent of the absorbed light energy into electrical energy. In 1927 it was proved that copper solar cells were more efficient. Both copper oxide cells and selenium cells are used in light light-sensitive devices, such as photometers. However these early solar cells still have efficiencies less than 1 percent. In 1941 silicon solar cells were developed by Russell Ohl. Silicon solar cells are more efficient than copper and selenium cells. Thirteen years later few scientist develop the silicon solar cell which are capable of six percent energy-conversion efficiency when used in direct sunlight. After 1980 silicon solar cells energy-conversion efficiency improved up to 37 percent. I thing the efficiency will increase up to 80 percent or more in future so we can use solar energy cheaply and the use of solar cells will be more common than today. Photovoltaic systems have profits and disadvantages according to other methods of producing energy. Photovoltaic systems are the alternatives to fossil or nuclear fuels for the generation of electricity. Photovoltaic systems are the cleanest way of producing electricity. They don’t pollute anywhere. And the source of photovoltaic systems is free. Photovoltaics widespread uses in areas where there are no power lines from utility grids such as space. Photovoltaics systems can operate long-term with absolutely no infrastructure, no roads, no technicians and no tools. But producing electricity efficiency is very low. So photovoltaic systems cost are higher than fossils or nuclear fuels. We know that photovoltaic cell converts sun lights into electricity. Sun lights include photons. Photons are the primary energy packets of sun lights. Photovoltaic systems include two or more layers of semiconductors which can absorb photons. The photons raise the en...