Solution-phase synthesis of alloyed Ba(Zr _{1− x} Ti _x )S ₃ perovskite and non-perovskite nanomaterials

Chalcogenide perovskites, especially BaZrS₃ and its related alloys, present a promising alternative to lead halide perovskites for optoelectronic applications due to their reduced toxicity and enhanced stability. However, the elevated temperature conditions necessary for preparing these materials create a barrier to their incorporation into thin-film devices. In this work, we report a solution-phase synthesis of colloidal nanoparticles of titanium-alloyed BaZrS₃, Ba(Zr_1-xTi_x)S₃. The titanium alloying was achieved using reactive amide precursors in oleylamine solvent, and N,N'-diethylthiourea served as the sulfur source. Our methodology allowed for the synthesis of Ba(Zr_1-xTi_x)S₃ nanomaterials at temperatures at or below 300 °C. The resulting nanocrystals exhibited a phase transition from an orthorhombic distorted perovskite structure to a hexagonal non-perovskite phase as the titanium content surpassed x = 0.11, accompanied by a morphological evolution from nanoplatelets to nanohexagons and ultimately nanobars. The UV-Vis-NIR absorption spectra of Ba(Zr_1-xTi_x)S₃ nanoparticles exhibit increasing low-energy absorption as the titanium content is increased. This work contributes to the development of low-temperature synthesis methods for Ba(Zr_1-xTi_x)S₃ nanomaterials, offering new potential pathways for materials design of chalcogenide perovskites for advanced optoelectronic applications.