As-Doped CdSeTe Solar Cells Achieving 22% Efficiency With −0.23%/°C Temperature Coefficient
Wyatt K. Metzger, D. Wes Miller, Rajni Mallick, Xiaoping Li, Wei Zhang, Ivy Wang, Alex Polizzotti, Tursun Ablekim, Dana H. Cao, Dylan Hamilton, Jeff Bailey, Chungho Lee, Sachit Grover, Dingyuan Lu, Gang Xiong
Abstract
Since its inception, CdTe-based solar technology has been manufactured by using Cu to dope the absorber and to form effective back contacts. Removing Cu and implementing group V dopants has significantly decreased degradation in accelerated lifetime tests. We demonstrate As-doped cells are now at a crossing point with longstanding Cu-based technology, reaching 22.2%–22.4% efficiency by internal testing and 22.0% certified efficiency. Fill factor and open-circuit voltage on exemplary samples have achieved values as high as 82% or 880–895 mV, respectively. At the same time, the normalized efficiency temperature coefficient is only −0.23%/°C, offering substantively greater energy yield.