Enhancing Black Phase Stability of CsPbI3 using Dimethylammonium Iodide: Mechanisms and Insights

Inorganic CsPbI3, with its 1.7 eV direct bandgap, shows great promise for photovoltaic applications, but its commercialization is hindered by phase instability under ambient conditions. Several strategies, including doping, particle size reduction, and surface functionalization, have been explored to improve stability. Among these, the use of dimethylammonium iodide (DMAI) has shown significant promise in stabilizing the black phase. The stability is influenced by annealing temperature and dwelling time, making it essential to understand the relationship between phase transformation, temperature, and DMAI’s role in stabilization. This study investigates CsPbI3 thin films with varying DMAI concentrations (x = 0, 0.2, 0.5, 0.8, 1, 1.2, 1.5, 2) through systematic in situ (heating-cooling) GIWAXS analysis, ensuring high-quality data for structural refinement.