High-efficiency, thin-film InP concentrator solar cells

The fabrication and characterization of thin-film InP solar cells designed for operation at high solar concentration ( approximately 100 suns) which have been prepared from similar device structures grown on GaAs substrates are discussed. The cell performance is characterized as a function of the air mass zero (AM0) solar concentration ratio (1-100 suns) and operating temperature (25 degrees -80 degrees C). From these data, the temperature coefficients of the cell performance parameters are derived as a function of the concentration ratio. Under concentration, the cells exhibit a dramatic increase in efficiency and an improved temperature coefficient of efficiency. At 25 degrees C, a peak conversion efficiency of 18.9% (71.8 suns. AM0 spectrum) is reported. At 80 degrees C, the peak AM0 efficiency is 15.7% at 75.6 suns. Approaches for further improving the cell performance are discussed.>