Organic bromide solutions-processed all-inorganic perovskite for efficient and stable photovoltaics

Abstract

All-inorganic CsPbI3-xBrx perovskites with appropriate band gap is an attractive semiconductor material for solar applications, whereas their phase stability plays a key role in high-efficiency perovskite solar cells (PSCs). Their device performance was severely constrained by defects, here we found that the promising phenylpropylamine bromide (PPABr) as a simple additive can effectively influence the crystallization kinetics and produce a bifunctional treatment of perovskite, Br ion doping, and organic cation surface passivation. The PPABr treatment has essentially little influence on the light absorption capacity of CsPbI3-xBrx, the band gap is somewhat widened, and the surface hydrophobicity and phase stability are enhanced. CsPbI3-xBrx perovskites treated with PPABr have altered interfacial properties and obtained better interfacial contact, resulting in improved charge extraction and decreased charge recombination. Furthermore, 2.5mol% PPABr treated CsPbI3-xBrx-based perovskite solar cells exhibited repeatable photovoltaic performance with a maximum efficiency of 13.14%. Within 150 hours under air circumstances, the PCE attenuation is controlled to within 5% during the test. Hence, passivating inorganic perovskite using organic bromides PPABr is a novel and promising strategy for developing stable, high-performance solar cells.