Conversion Efficiency Calculation Of The Third Generation Solar Cell

With the problem of environmental pollution and resource exhaustion becoming increasingly imminent, most countries over the world have been adopting sustainable policy in the utilization of resource in recent years. Solar energy is to human beings inexhaustible and is also the cleanest resource that can be directly utilized. Electricity generating with the application of photovoltaic effect has now engaged much attention. Solar cell is one kind of semi-conductor devices that converts solar energy directly into electrical energy.Solar energy as clean and recursive resource has been increasingly recognized as important. The development of solar cell has mainly undergone three stages as follows: Most solar cells presently on the market are based on silicon wafers, the so-called 'first generation' technology. As this technology has matured, costs have become increasingly dominated by material costs, mostly those of the silicon wafer. At the same time, with a view to its high production cost, people have to develop film solar cell at the cost of the reduction of its conversion efficiency. Then, for the past 15 years, a switch to a 'second generation' of thin-film cell technology has seemed imminent. Thin films also offer other advantages, particularly the increase in the unit of manufacturing from a silicon wafer (～100cm~2) to a glass sheet (～1m~2), about 100 times larger. However, to progress further, conversion efficiency needs to be increased substantially. Nevertheless, The Carnot limit on the conversion of sunlight to electricity is 95% as opposed to the theoretical upper limit of a standard solar cell. This suggests the performance of solar cells could be improved considerably in the production of 'third generation' of high-performance, low cost photovoltaic products. In the following decades, the third generation film solar cell with high conversion efficiency can undoubtedly be developed to a great extent.This thesis based on the detailed balance between the light absorb and light excited calculated the upper limit for the conversion efficiency of single junction solar cell. Discussed the upper limit for the conversion of solar energy, derived the conversion efficiency of impact ionization solar cell,three band and four band solar cell, simulated by Matlab, and analyzed the result.