The quest for efficient and cost-effective thin-film photovoltaic (PV) materials has recently zeroed in on hybrid lead halide perovskites, owing to their low cost, ease of processing, and exceptional efficiency metrics—peaking at 33.9% when combined with silicon in tandem devices. Nevertheless, there are substantial concerns about the stability, toxicity, and consequential environmental footprint of lead-based perovskites, thereby necessitating rigorous research to identify and develop alternative materials with superior stability profiles and diminished toxicity. Amongst the myriad candidates, chalcogenide perovskites and their related structures, represented by the empirical formula ABQ3 (with A = Ca, Ba, Sr; B = Zr, Hf, Ti; Q = S, Se), have emerged as particularly promising contenders. These materials are distinguished by their optimal optoelectronic properties and robust stability. Notably, barium zirconium sulfide, BaZrS3, has garnered significant attention in the scientific community due to its distinctive perovskite structure and several unique optoelectronic properties, making it a frontrunner in this domain of PV materials research. However, synthetic routes to these materials, especially as colloidal nanomaterials, remain limited, due in part to their high crystallization energy and oxophilicity. In this thesis, we have successfully devised solution-based approaches to synthesize colloidal nanomaterials of BaTiS3 and BaZrS3, including its titanium- and selenium alloyed phases. Our methodology involves utilizing reactive metal amide precursors in oleylamine, with diethylthiourea and trioctylphosphine selenide serving as sources for sulfur and selenium, respectively. Chapter I discusses the general background of current and emerging PV materials. Chapter II delves into various synthetic routes reported for inorganic ternary and binary sulfide and selenide nanomaterials, incorporating transition metals from groups 3, 4, and 5. This section also encompasses our synthetic methods for BaZrS3 and BaTiS3 colloidal nanomaterials. Chapter III provides an in-depth discussion of our developed techniques for producing nanorods and nanoparticles of barium titanium sulfide. In Chapter IV, our focus shifts to the synthesis of colloidal nanoparticles of barium zirconium sulfide perovskites. Additionally, Chapter V explores the synthesis of titanium and selenium alloyed barium zirconium sulfide. Finally, the synthesis of mixed halide lead perovskite nanocrystals, achieved through a postsynthetic anion-exchange method, is discussed in Appendix E.

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