In-Situ Thermal Treatment Analysis on Site Based Doping in Single and Double Perovskite-Halides

Perovskite halide compounds with ABX₃ stoichiometry (A: monovalent Cs, B: metals, and X: halides) are highly flexible in terms of elemental substitutions while retaining the same crystalline symmetry, making them a powerful principal material in optoelectronic applications. However, there is an outsized effect (e.g. degradation) on these materials due to environmental conditions. To mitigate the decaying stability under practical and extreme environmental conditions and inherent disorder when doped, we seek to study the effects that specific site substitutions have on the stability in perovskite halides. Therefore, we synthesized a variety of single and double perovskites via solid state solutions and solvent precipitation as a function of the B- and X-site substitutions. Compositional analysis was performed with X-ray Photoelectron Spectroscopy and Energy Dispersive X-ray analysis to confirm homogeneity in the materials, while X-ray Diffraction with in-situ atmospheric control, e.g. elevated temperatures (23 – 600°C) and various gaseous atmospheres (N₂, partial vacuum, etc.) was utilized to stress these structures. By tracking material changes such as phase decomposition and melting temperatures we see an increase in structural stability when changing the X-site from I, Br, and Cl respectively thus indicating site-based doping is effective in enhancing perovskite halides stability for applications.