Progress Toward 1000-mV Open-Circuit Voltage on Chalcopyrite Solar Cells

Previously, an open-circuit voltage of 960 mV was reported on Se-free Cu(In,Ga)S
₂
(CIGS) solar cell with a CdS buffer layer. In this paper, we report our latest progress toward 1000 mV on a Se-free Cu(In,Ga)S
₂
solar cell with a Cd-free buffer layer. The highest open-circuit voltage of 973 mV was demonstrated by rapid thermal annealing and Zn
_1-x
Mg
_x
O buffer layer application.