Advances in Chalcogenide Crystal Growth

Chalcogenides are the cornerstone of the semiconductor and thermoelectric industries and are up-and-coming materials for superconductors, catalysis, and battery applications. Challenges in the synthesis of those materials emerge from the chalcogen’s volatility and the tendencies of chalcogenide to react with even trace quantities of oxygen. Nonetheless, many techniques have been applied to the growth of chalcogenide single crystals, which are convenient for structure determinations and intrinsic property measurements. This dissertation will detail synthetic strategies applied to the crystal growth of novel chalcogenide materials via molten flux preparation (Chapters 2, 4, and 5), hydrothermal synthesis (Chapter 1 and 3), and single-crystal-to-single crystal (SCSC) modifications (Chapters 1, 2, 3, and 4). The first chapter discusses flux crystal growth coupled with the boron-chalcogen mixture method for synthesizing NaCuNpS3. Moreover, ACuUQ3 (A = Na, K; Q = S, Se) undergoes an SCSC water intercalation process within the layers. In the second chapter, we demonstrated the hydrothermal crystal growth of all-inorganic open-framework chalcogenides A3Ga5S9·xH2O (A = Rb, Cs) and novel post-synthetic oxychalcogenide formation. Flux crystal growth of salt-inclusion chalcogenide family [Cs6X]AGa6Q12 (A = Na, K, Rb; X = Cl, Br; Q = S, Se) is the focus of the third chapter. Additional SCSC ion-exchange reactions were found to yield two compositions: [Cs6F]NaGa6S12 and [Cs6Br]RbGa6S12, inaccessible through the traditional synthetic route. Finally, in the fourth chapter, we considered how flux composition affects the formation of different compositions and polymorphs in the Na–Ga–Q (Q = S, Se) system.