Vacancy-Catalyzed Cation Homogenization for High-Performance AgBiS<sub>2</sub> Nanocrystal Solar Cells
Yang Liu, Zitao Ni, Lucheng Peng, Hao Wu, Zeke Liu, Yongjie Wang, Wanli Ma, Gerasimos Konstantatos
Abstract
Environmentally friendly silver bismuth sulfide (AgBiS 2 ) nanocrystals (NCs) are promising solution-processed absorbers for photovoltaic applications. Cation disorder nonhomogeneity has been considered as a prevalent obstacle, significantly impacting the optoelectronic properties of AgBiS 2 films. In this work, we developed a vacancy-assisted strategy to mitigate the energy barriers for the cation homogenization process in AgBiS 2 NC films. Chloride ions are introduced to induce surface vacancies, leading to improved cation homogeneity and enhanced absorption under low-temperature annealing. The resultant AgBiS 2 NC solar cells exhibited a power conversion efficiency (PCE) over 10%, the highest to date from a solid-state ligand-exchange method. Our strategy not only enables high-quality AgBiS 2 NC films but also provides an approach for engineering cation disorder in multinary materials.