Solar panels
The energy of solar radiation can be converted into direct current by solar cells - a device consisting of thin films of silicon or other semiconductor materials. The advantage of photovoltaic cells (solar cells) due to the lack of moving parts, their high reliability and stability. However their service life is practically unlimited. They have a small mass, are simple maintenance, effective use of both direct and diffused solar radiation. Modular types of design that allows installation of virtually any power and makes them look very promising. The disadvantage of solar cells is the high cost and low efficiency (now almost 10-12%).
Photoelectric effect occurs in the solar cell when it is illuminated by light in the visible and near infrared spectral regions. In the solar cell of semiconductor silicon thickness of 50 mkm absorbed photons and their energy is converted into electricity through a pn connection.
Go to type of gallium arsenide and aluminum, the use of concentrators of solar radiation with a multiplicity of concentration 50-100 improves efficiency from 20 to 35%. In 1989, the firm Boeing has created two-layer element consisting of two semiconductors - gallium arsenide and antimonide Ghalia - with a conversion efficiency of solar energy into electrical energy, equal to 37%. In conventional silicon cells, infrared radiation is not used, whereas in the new element in the first transparent layer (arsenide Portugal) is absorbed and converted into electricity to visible light and infrared wavelengths, which passes through this layer is absorbed and converted into electricity in the second layer (gallium antimonide), as a result of efficiency is 28% +9% = 37%, which is quite comparable with the efficiency of modern thermal and nuclear power plants.
Solar panels still used primarily in space and on Earth only for power autonomous consumers up to 1 kW power radio navigation and low-power electronics equipment and presents experimental electric vehicles and aircraft. In 1988 in Australia , the first world solar car rally. With the improvement of solar panels they will find application in homes for the independent power supply, i.e. heating and hot water, as well as to generate electricity for lighting and power appliances