Phase-Controlled Synthesis of Cu2SnS3 Nanocrystals: The Effect of Redox Conditions on the Initial Binary Cu2–xS Nucleation

In this work, it is shown that both pure zincblende and wurtzite structures of Cu 2 SnS 3 (CTS) nanocrystals (NCs) have been synthesized by a facile one-spot heating-up procedure. By controlling the solvent ratios, different phase components of zincblende and wurtzite mix-phase CTS NCs were also obtained. The effect of different precursors and surfactants on the phase selectivity of CTS NCs was investigated, and a phase-controlled mechanism is proposed: the crystal structures of the resulting CTS NCs are related to the initial structure forms of the Cu x S seeds, and the different phase structures are formed as a result of the initial redox conditions. When the reaction was conducted under reducing conditions, Cu 2 S (or Cu 31 S 16 ) seeds were formed, leading to the formation of wurtzite CTS nanocrystals. When the conditions were less reducing, the initial CuS (or Cu 1.84 S) seeds resulted in the zincblende structure CTS nanocrystals. Graphical Different phase components of zincblende and wurtzite mix-phase Cu 2 SnSe 3 nanocrystals (NCs) were obtained. The phase selectivity of the Cu 2 SnSe 3 NCs is related to the initial redox conditions. Wurtzite Cu 2 SnSe 3 NCs formed because of the Cu 31 S 16 seeds, and the CuS seeds led to zincblende structure Cu 2 SnSe 3 NCs.