Since photovoltaic cells (PVs) produce greater quantities of electricity when illumination increases, researchers are examining the use of highly concentrated sunlight for irradiating photocells. If PV current levels of a single cell could be raised 10s or 100s of times, total costs of the semiconductor, the solar concentrating device, and the cell modules would fall within acceptable values, and solar production of electrical energy would become competitive.
Eugene Katz, , Jeffery Gordon, and Daniel Feuermann of the Department of Solar Energy and Environmental Physics, at the Blaustein Institutes for Desert Research have investigated the use of high-efficiency triple-junction solar cells with a special, minidish-fiber optics light concentrating device, designed by Gordon and Feuermann.
The researchers were able to measure cell behavior under a broad range of light concentrations, up to 10,000 suns. They found that the efficiency of such solar cells increases from 24% at normal solar irradiation (one sun) to a maximum of 32% at about 1000 suns, after which a moderate decrease is observed. However, since operation is possible with 5000 or more suns, this decrease in efficiency is not significant. The researchers also found no damage, no major internal loss of current, or pronounced deterioration of cell performance even under maximum of irradiation of 10000 suns. Their studies also indicate that efficiencies of the concentrator PV approach could be improved if the cells were reduced in size, down to 1 sq mm (0.002 sq in), for example.
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