Towards the end of the previous century, the humanity understood very clearly two facts – first, the World supplies of fossil fuels (coal, oil, gas, uranium) are limited, and, second, industrial development and classical generation of electrical energy seriously endanger the environment. Renewable energy sources (sun energy, wind energy, bio fuels, etc.) are based on the use of natural fluxes of energy (Masters,2004). That is why they are considered to be inexhaustible. In specific cases of implementations, for example in lighting, a direct generation of electrical energy using photovoltaics is outlined as a long-term one.
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Towards the end of the previous century, the humanity understood very clearly two facts – first, the World supplies of fossil fuels (coal, oil, gas, uranium) are limited, and, second, industrial development and classical generation of electrical energy seriously endanger the environment.
Renewable energy sources (sun energy, wind energy, bio fuels, etc.) are based on the use of natural fluxes of energy (Masters,2004). That is why they are considered to be inexhaustible.
In specific cases of implementations, for example in lighting, a direct generation of electrical energy using photovoltaics is outlined as a long-term one.
The name photovoltaic comes from the combination of two Latin words – “photos” means light and “volt” means a measurement unit for electromotive force. The unit volt derives its name after the Italian scientist Alessandro Volta (1745-1827) who discovered battery (primary electrochemical source of electrical energy). The photovoltaic is used to convert sun energy into electricity. The official discovery of the photovoltaic is assumed to be made by French scientist Alexadre-Edmond Becquerel (1820-1891) in 1839. He discovered the effect upon silver plates. First data about photovoltaic effect in solid materials dated from 1877. Adams and Dew described variations, which they had monitored of electrical capabilities of selenium when it was left on sunlight, i.e. they discovered the photovoltaic effect in non-metals. In 1883, Charles Fritz, an electrician from New York, designed sun cell from selenium closed in quite high number of aspects to silicon cell used nowadays. The selenium cell consisted of a thin plaster of selenium, covered with very thin semi-transparent level of golden filaments and it was protected from a piece of glass. This cell was rather inefficient one.
The first solar cells had efficiency less than 1%. Nevertheless, the selenium cells began to be used in photography. The main reason for inefficiency of these devices became known later in first decades of XX century when physicists as Max Planck (1858-1947) developed new features in fundamental property of materials.
The break in high-efficient solar cell use started in 1950 in Bell Laboratories in New Jersey with an assistance of several scientists: Daryl Chapin, Calvin Fuller and Gerald Pearson. They made a research into influence of the light upon semiconductors.
In 1953 the team Chapin-Fuller-Pearson, relying on previously made discoveries in Bell laboratories about photovoltaic effect in silicon, created enriched silicon parts. These parts were more effective then the previously used one for obtaining electricity from sun light. The team succeeded to increase the efficiency of their cells up to 6%. Bell laboratories started to demonstrate the practical usage of solar cells for supplying provincial telephone stations in the midst 50th.
In 1958 however, solar cells started to be used for a supply of little radio-transmitters in the fourth American satellite Vanguard I. After these first successful demonstrations, photovoltaic usage as energy source turned to be universal for space ships. Fast headway in development of the photovoltaic cells and reduction of their price and their size contribute to their entering in cosmic and electronic industry during the last several decades. Networks of connected photovoltaic stations operate in the time being in USA, Germany, Italy, Switzerland, Spain, Japan, Mexico, etc. Photovoltaic supply networks are used in industry and business buildings.
The efficiency of the best silicon cell reached in laboratory environment is 24% while the efficiency of the best photovoltaic modules, which operate and are offered nowadays is about 16%.
“Spectrolab” under financing of the government was demonstrated solar cells with an optical concentrator of record-breaking efficiency of 40.7% (King, 2007). The technology is based on common structures of sun elements, thus, it allows to be caught a wider part of sun spectrum using several levels in each element. Each element catches a segment of sun light thus allowing more efficient conversion of energy.