Evaluation of thin-film solar cell temperature coefficients for space applications

At present, commercially available thin-film photovoltaic cells are evaluated for terrestrial applications. To apply thin-film photovoltaic cells for space applications, the assessment of the solar cell performance must be conducted in simulated space conditions. We investigated the temperature coefficients of the I-V characteristics of thin-film amorphous silicon (a-Si) solar cells manufactured by Uni-Solar and Iowa Thin Film Technologies, and CuInGaSe2 (CIGS) solar cells manufactured by MicroSat Systems with simulated space solar radiation. The temperature coefficient of the thin-film solar cells between temperatures of 15 and 100degreesC was measured with a temperature-controlled vacuum plate. The vacuum plate ensures maximum thermal contact between the plate and the solar cell as well as reducing the thermal gradient in the solar cell. The vacuum plate also serves as a thermal reservoir that provides temperature stability during the performance evaluation when the solar cell is exposed to simulated sunlight radiation. An X-25 sunlight simulator calibrated for AM0 conditions provides the necessary radiation in performance characterization of the thin-film solar cell. The I-V characteristics of the solar cell were obtained at various temperatures to gain a thorough knowledge of the cell's performance at different temperatures. Copyright (C) 2005 John Wiley Sons, Ltd.