Rear-Passivation Effect on Thin-Film Perovskite/u-CIGS Tandem Solar Cell Performance

This work presents an improved Perovskite/u-CIGS tandem solar cell architecture, exhibiting significantly enhanced conversion efficiency and higher reliability compared to existing solutions in the literature. At the bottom cell level, traps (D<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">it</inf>) were identified at rear u-CIGS/Al<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> interface as a key factor degrading conversion efficiency by promoting carrier recombination. Mitigating this mechanism is essential for improving the stability and performance of solar cells. Incorporating a negative fixed charge density (Q<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</inf>) in the Al<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> layer offers a promising solution, providing effective field-effect passivation to minimize minority carrier recombination at the rear surface. The proposed tandem device achieves an impressive efficiency of 23.28% using a cell pitch of 1.5 μm and silver as the back specular contact.