Synergistic\nEnhancement of <i>V</i><sub>OC</sub> in Tin Halide Perovskite\nSolar Cells Through Growth Annealing\nTemperature Optimization via Mitigating Bulk Defects and Nonradiative\nRecombination

Large organic cation mixed tin-halide\nperovskites (LOTHP) have\nemerged as a promising nontoxic alternative to lead-halide counterparts,\noffering improved power conversion efficiency (PCE) and stability.\nThe influence of various growth-annealing temperatures (ga-T) on these\nmaterials, typically processed above 70 °C, has been poorly understood.\nThis study explores ga-T ranging from 40 to 120 °C, revealing\nthat higher ga-T significantly enhances perovskite film crystallinity,\nincreases crystallite size, and reduces both nonradiative recombination\nand bulk defect density. Consequently, these outcomes lead to a substantial\nboost in photovoltaic performance, evidenced by a 130% increase in\nopen-circuit voltage (<i>V</i><sub>OC</sub>) and a 33% rise\nin current density (<i>J</i><sub>SC</sub>) at ga-T ranging\nfrom 40 to 100 °C. Computational simulations further validate\nthese experimental findings, exploring the structural changes, defect\ndensity variation, and energy level shifts in LOTHP. These combined\ninvestigations elucidate the underlying driving mechanisms behind\nreduced nonradiative losses and improved energy level alignment with\ntransport layers, significantly enhancing the <i>V</i><sub>OC</sub>. These findings underscore the significance of ga-T in optimizing\nthe electronic quality of tin-halide perovskite films for a superior\nsolar cell performance. Understanding these temperature-dependent\neffects is crucial for advancing the development of efficient and\nstable large area tin perovskite-based photovoltaics.