Selenium Vacancy-Ordered Halide Double Perovskites

Halide perovskites are a highly tunable class of materials with the potential for a variety of optoelectronic applications, as exemplified by the efficiency of experimental methylammonium lead iodide solar cells. However, compared to commercial standards like silicon, the current set of these materials and their variations are relatively unstable. Stability considerations are therefore critical in determining the viability of any new halide perovskites. I present tests evaluating the stability of selenium vacancy-ordered halide double perovskites synthesized from solution, which are of the form A2SeX6 (A = K+, Rb+, Cs+; X = Cl-, Br-). These tests characterize the decomposition of these compounds under air, water, and heat. Energy calculations from density functional theory (DFT) confirm the favorability of decomposition reactions. These DFT calculations also indicate the readiness of perovskite formation, which can help predict if a synthesis is viable and if the perovskite will remain stable even under its ideal conditions.