In-Situ Thermal Treatment Analysis of the Stability of Perovskite-Halides in Harsh Environments

In the study of perovskite-halides, we seek to understand the disorder not only caused by site doping but also from the decaying stability under harsh environmental conditions. Where their lack of stability under conditions such as elevated temperatures, humidity, oxidizing gases, and long-term ultra-violet exposure hinder their integration into next generation optoelectronic devices. Here we present materials that use the inherent flexibility of the perovskite halide stoichiometry (ABX₃) to substitute elements into the A and B sites. Understanding the mechanism behind material degradation (e.g. phase segregation, structural transformation, oxidation) is crucial to mitigate decreased functionality and increase the stability of halide perovskite materials. We will present structural characterization of nanoparticle powders and thin films of perovskite halides (e.g. CsPbBr₃ and Cs₂AgBiBr₆), which were synthesized via solid state solution and solvent precipitation. Utilizing X-ray Diffraction (XRD) with in-situ control of temperature (23 – 300°C) and gaseous atmospheres (e.g. Air, H₂, O₂) we are able to identify the specific conditions that induce changes in the crystal lattice relating to structural changes and material decomposition temperatures. Looking at CsPbBr₃ and Cs₂AgBiBr₆ we find that the perovskite halides are altered in structure where we either see a stabilization in single phase and/or additions in secondary phases induced by the harsh high temperature environment.