Halide-driven polymorphism in metal chalcogenides as a system of study for mechanistic understanding of nanoparticle synthesis

Abstract

This thesis discussed the polymorph control of metal chalcogenides as a system of study for deeper mechanistic understanding of nanoparticle synthesis. Chapter 1 provides a brief introduction to the origins of nanoparticle chemistry, nanoparticle synthesis, and synthetic handles for controlling the properties of the nanoparticles. Chapter 2 provides the in-depth study of manganese sulfide (& selenide) and its crystal structure control by means of halide precursor selection. This chapter details the ex-situ study of possible hypotheses for the mechanism of this polymorphism. Chapter 3 contains the preliminary XAS work that was conducted for the study of the manganese- halide- OLAM complexes formed in the reactions complemented by computational data from the Wexler group. Chapter 3 also contains time-resolved XANES data which will require additional measurements and calculations to fully explain. Chapter 4 expands the halide-driven polymorphism to the tin sulfide system. Preliminary data in Chapter 4 reveals that not only does the halide influence the polymorphism, but that the sulfur: OLAM chemistry may also be involved. Chapter 5 describes the first synthetic route for the direct colloidal synthesis of nanoparticle manganese telluride.