Arsenic-Doped CdSeTe Solar Cells Achieve World Record 22.3% Efficiency

Abstract

For more than three decades, Cu has been critical to dope CdSeTe solar cells, form effective contacts, and maximize efficiency. At the same time, Cu defect chemistry has limited stability, carrier concentration, and further efficiency improvements. In this article, 22.3% world record efficiency is demonstrated without Cu by implementing As doping, which also improves stability, temperature coefficient, and energy yield. The efficiency crossing point of Group V technology relative to Cu has been driven by steady improvements in the open-circuit voltage. Here, the certified record cell reaches open-circuit voltage of 899 mV while retaining high photocurrent values of 31.4 mA/cm2; the fill factor is relatively low at 78.9%. Coupling 80% fill factor with top open-circuit voltage values of 917 mV reported here offers a near-term path to 23% efficiency. Characterization indicates reducing recombination and improving activation provide viable paths to 25% efficiency.