Effect of Perovskite Defect Passivation on Solar Cell Performance

Abstract

Perovskite solar cells (PSCs) have demonstrated power conversion efficiencies of more than 27%, making them formidable opponents to known photovoltaic technologies. Nonetheless, commercial adoption is still limited by material defects, especially at bulk, grain boundaries, and interfaces. These impurities lead to the migration of ions, enhanced recombination, hysterical failure, and low environmental stability. This review explores the latest passivation strategies of defects that have been devised to counter such challenges. We discuss several strategies such as conjugated ammonium salts, 2D/3D layer-based structures, zwitterions, and interfacial treatments, and assess their utility in enhancing device performance and service life. The characterization methods, including photoluminescence spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy and Solar Cell Capacitance Simulator simulations, are given special consideration and have enhanced our knowledge on defect behavior. We also discuss the use of encapsulation and grain boundary control to protect devices against the effects of moisture and heat degradation especially with large-area cells. In the process, we tie these strategies to enhancements in key performance measures such as open-circuit voltage, short-circuit current, and fill factor. This review will be of practical use to the researchers engaged in reaching more stable and scalable PSCs to apply them in the real world.