Holistic dielectric and buffer interfacial layers enable high-efficiency perovskite solar cells and modules

Abstract

Suppressing the interfacial non-radiative recombination plays a critical role in reducing the voltage loss of perovskite solar cells. Herein, we develop a holistic interfacial regulation using dielectric materials of Al2O3 and PEABr/PMMA, and a buffer layer of compact SnOX to manipulate the multiple interfaces. A compact SnOX is inserted to reduce the charge accumulation at the interface of electron transport layer/Ag. Through this multiple interfacial design, the power conversion efficiency is greatly increased from 22.66% to 25.70% (certified 24.23%), mainly attributing to much enhancement in open circuit voltage and fill factor. The fill factor of 86.41% is the highest among the self-assembled-monolayers-based inverted devices. Both perovskite film and resulting device show increased thermal stability due to the incorporation of compact SnOX, which inhibits the escape of volatile species from perovskite, infiltration of moisture and the suppression of ion migration. Scaling up this strategy delivers an efficiency for a minimodule as high as 21.56%. More importantly, we discovered that the PEABr passivation could induce the collapse of morphology under continuous illumination, thus leading to worse operational stability. This work provides a path towards omnibearing modification for minimizing the trap-assisted recombination at the interface through the synergetic effects of dielectric materials.