(262f) Structure and Composition Tuning of Bismuth-Halide Perovskites

Halide perovskites are a promising optoelectronic semiconducting material with a variety of potential applications. Issues with stability and toxicity in the standard hybrid lead halide perovskites have led to many different proposed solutions. Replacing the organic cation with cesium, using heterovalent metal cations to replace lead, and layering the perovskite material with protective, bulky ligands are all explored solutions. We combine three of these avenues to synthesize layered double perovskites of phenethylammonium cesium silver bismuth bromide. We find that the single layer version of this material undergoes an interesting structural transition around 140C that results in an optically evident color change prior to melting. We investigate this material and transition with absorbance, single-crystal x-ray diffraction, and combined differential scanning calorimetry and thermogravimetric analysis.