Analysis of losses in high-efficiency CdTe cells

High-efficiency (⩾15%) CdTe solar cells, fabricated at the University of South Florida, show favorable features in their diode junction characteristics. At any selected voltage, forward current is smaller than that reported for other CdTe cells. Variable-intensity measurements show the diode quality factor A increases gradually between 0 and 100 mW/cm², and is less at operating intensities than seen in other cells to date. Series and shunt resistances decrease continuously with intensity, but most of the decrease occurs below 10 mW/cm². Temperature dependent measurements show a 1.8 mV/K decrease in the open-circuit voltage and an approximate 1.4 V zero-temperature extrapolation. The difference between the translated light curve and dark curve in the operating range is 50 mV at higher temperatures and 70 mV at lower ones. Examination of several cells over a 3-month period shows the elimination of an increase in series resistance seen in the previous highest-efficiency cell