Synthesis of BaTi(S_xO_1-x)₃ Chalcogenide Perovskites Using the Salt Flux Method with NaCl: Photoluminescence Studies

Chalcogenide perovskites are an emerging class of semiconductor materials with attractive optoelectronic properties, such as a high absorption coefficient, tunable bandgap, high dielectric constant, impressive excited-state dynamics, and ambipolar transport properties. They surpass their halide perovskite counterparts in terms of stability and consist of earth-abundant and non-toxic constituents. Although BaTi(S_xO_1-x)₃ has a slightly higher bandgap, it remains viable as a top absorber in a tandem solar cell. Additionally, it could be valuable for future optoelectronic and energy-conversion technologies, including indoor photovoltaics, light-emitting diodes, and water-splitting applications. Obtaining high-quality samples is essential for examining their inherent physical properties. In this study, single crystals were grown using the salt flux method in sealed quartz ampoules with NaCl flux. The role of NaCl flux is identified as being pivotal for the rapid synthesis of BaTi(S_xO_1-x)₃ perovskite at moderate-to-high temperatures. Moreover, sharp photoluminescence was observed for BaTi(S_xO_1-x)₃, suggesting that chalcogenide perovskites possess outstanding optical and optoelectronic properties. Our research presents the first example of this important category of BaTi(S_xO_1-x)₃ Chalcogenide perovskite materials, illuminating both synthetic manipulation techniques and potential application integrations for such promising materials. Thus, our work is poised to significantly contribute to the ongoing efforts to develop efficient lighting materials with minimized environmental toxicity.