Hexagonal ABX₃ nanocrystals: rod-shaped BaNbS₃ and BaTaS₃; BaTiSe₃, BaZrSe₃, and other selenide derivatives for optoelectronic applications

Chalcogenide perovskites have increasingly garnered attention in recent years for various optoelectronic applications. While distorted perovskites such as BaZrS₃ are primarily being explored for photovoltaic applications, hexagonal ABS₃ compounds such as BaTiS₃ have been proposed for optical devices and thermoelectrics due to their intriguing properties arising from their quasi-1D structure, which imparts anisotropy in properties. However, other members of the hexagonal family remain largely unexplored, likely due to their harsh synthesis conditions. In this report, we synthesize nanocrystals of relatively unexplored members of the hexagonal ABX₃ chalcogenides family, which also possess a similar rod-like morphology and could be useful for polarized photodetection applications. Specifically, we modified our previously reported sulfide perovskite nanoparticle synthesis route to produce BaNbS₃ and BaTaS₃ nanocrystals. Furthermore, we explored selenium and selenourea as precursors to synthesize selenide hexagonal nanocrystals such as BaTiSe₃ and BaZrSe₃, as well as other selenide analogues like Ba₃Nb₂Se₉ and Ba₃Ta₂Se₉. This marks the first report of nanocrystal synthesis for the BaMSe₃ family, where M is an early transition metal.