In-Situ Thermal Treatment Analysis on Elemental Doping in Single, Double, and High Entropy Metal Halide Perovskites.

Perovskite halide compounds are highly flexible in terms of elemental substitutions making them a powerful principal material in optoelectronic applications due to varying emergent properties and stability. However, environmental conditions (e.g. degradation) have an outsized effect on their properties. To understand the decaying stability under practical and extreme environmental conditions and inherent disorder, we seek to study the effects of site substitutions on the structural stability in metal halide perovskites. Thus, a subset of single, double, and high entropy perovskites were synthesized as a function of B- and X-site substitutions in the ABX₃ structure. Compositional analysis was performed to confirm stoichiometric homogeneity in the materials, while X-ray diffraction with in-situ atmospheric control was utilized to stress these structures. By tracking material changes such as phase transitions, phase decomposition, and melting temperatures heating stage temperature conversions were employed to reproduce calculated and previously confirmed structural transitions and onsets of decomposition in principle single metal halide perovskites. As a result, we implemented our confirmed methodology to observe heightened structural stability of emergent double and high entropy perovskites. Indicating site-based doping can be effective in enhancing perovskite halides structural stability for temperatures standard in industry applications.