Three-dimensional distribution of amino groups improves perovskite crystallization and defect passivation in high-performance photovoltaics

Abstract

Incorporating organic molecules with diverse functional groups to improve film quality has emerged as a crucial strategy for realizing high-performance perovskite solar cells (PSCs). Nevertheless, the role of spatial distribution of those functional groups in governing passivation efficacy and perovskite crystallization remains insufficiently investigated. Here, we introduce three amino-containing molecules, bis(4-aminophenyl)methane (2APM), tris(4-aminophenyl)methane (3APM) and tetrakis(4-aminophenyl)methane (4APM), featuring distinct spatial distributions of amino groups, into the perovskite precursor solution as in-situ regulators. Among them, 4APM exhibits the strongest interactions with PbI2 and formamidinium iodide (FAI) by virtue of its three-dimensional (3D) distribution of amino groups, most effectively suppressing undercoordinated Pb2+ defects and enhancing perovskite film crystallinity. As a result, PSCs incorporating 4APM achieve a stabilized power conversion efficiency (PCE) of 26.26%, while retaining over 95% of their initial efficiency after 1000 h of continuous operation at maximum power point under 1-sun illumination in a N2 atmosphere at 65 °C. Furthermore, 4APM-based perovskite solar modules (PSMs) with an active area of 14.0 cm2 deliver a PCE of 23.16%. Our findings underscore the critical role of functional group’s spatial distribution in the rational design of molecular passivators for perovskite photovoltaics.