Perovskite solar cells with boosted device performance through the incorporation of formamidine acetate processing additives

Metal halide perovskites are renowned for promising photovoltaic materials for approaching cost-effective solar cells. The prevalent method for crafting metal halide perovskite thin film leads to extensive defects and fragile interfacial contacts, resulting in severe non-radiative charge carrier recombination and ion migration, consequently decreasing both efficiency and stability of perovskite solar cells. In this study, we report enhanced efficiency and stability of perovskite solar cells with suppressed photocurrent hysteresis through the incorporation of formamidine acetate as the processing additive in the preparation of metal halide perovskite thin film. Systematically studies indicate that the formamidine acetate processing additives could enlarge the crystallinity and effectively suppress the defect as well, resulting in boosted and balanced charge transport of the resultant metal halide perovskite thin film. As a result, the perovskite solar cells based on the metal halide perovskite thin film processed with the formamidine acetate additives exhibit 22.29 % of power conversion efficiency, which is more than a 17 % enhancement compared to those based on the pristine metal halide perovskite thin film. Moreover, the perovskite solar cells based on the metal halide perovskite thin film processed with the formamidine acetate additives could maintain its 50 % initial efficiency value for nearly 1400 h of operation and suppressed photocurrent hysteresis. Our studies present an effective strategy to approach high-performance perovskite solar cells.