Perovskite-Inspired High Stability Organometal Antimony(V) Halide Thin Films By Post-Deposition Bromination

Metal-organic or all-inorganic Sb(V) bromide complexes are a novel class of semiconductor materials with potential use in optoelectronic devices. The implementation of these materials for optoelectronics is currently prohibited by their poor thermal stability and crippling solvent compatibility issues. Here, we address these limitations by introducing a new method for the synthesis of Sb(V) bromide complexes and thin films. The "post-deposition bromination" method presented here enables the fabrication of presumably any Sb(V) complex not previously accessible as thin films. We screen a set of Sb(V) bromides, identifying two promising candidate materials incorporating tetraethylammonium (TEA) or 2-chloro-N-methylpyridinium (CNMP). To prove the validity of the methods introduced in this work, we fabricate high-quality thin films of these complexes for the first time. Thin films of these materials are stable up to 110 degrees C (based on TGA measurements), which is significantly higher than the previously reported state-of-the-art complex from N-ethylpyridinium (NEP, approx. 50 degrees C). Additionally, cation dependent band gap tunability is observed with thin films of the novel complexes having a direct band gap at 2.20 (CNMP) and 2.55 eV (TEA) as determined by optical analysis. The methodology introduced in this study provides an unprecedented platform for research into metal-organic Sb(V) thin film materials.