Straightforward and green synthesis of all-inorganic CsPbI3 perovskite solar cells via nickel acetate incorporation

Abstract

Research on stable inorganic perovskite CsPbI₃ has emerged as a promising alternative to organic–inorganic hybrid perovskites due to its notable thermal stability and suitable bandgap (∼1.73 eV) for single-junction and tandem solar cells in both indoor and outdoor applications. However, CsPbI₃ films with large grains and low trap densities are required to achieve high-performance and stable perovskite solar cells. In this study, we present a novel synthetic strategy in which nickel acetate (Ni(AcO)₂·4H₂O) is incorporated in a pure DMSO CsPbI₃ precursor solution leading to the formation of stable γ-CsPbI₃ (black phase) nanocomposite perovskite films, as evidenced by XRD analysis. Moreover, the absence of detectable residual PbI₂ further confirms the enhanced conversion efficiency facilitated by Ni(AcO)₂ addition in our target when compared with pure CsPbI₃. Using this DMAI/HI-free approach, our top device with 0.1 M Ni(AcO)₂ (7.1 mol%) achieves over 12% power conversion efficiency in n–i–p mesoscopic configuration, with a lifespan exceeding 600 hours at maximum power point (MPP) and minimal losses (<20%) without encapsulation under controlled inert atmosphere. Besides, efficiencies over 15 and 17% are achieved under cool and warm white low-intensity illumination conditions, respectively, underscoring its potential for energy harvesting in indoor environments. The life cycle assessment (LCA) indicates that this new synthesis strategy reduces global warming potential (GWP) by 70% and eliminates hazardous chemicals like DMF and toluene. However, Ni(AcO)₂ and PbI₂ remain in the absorbing layer, requiring careful consideration.