Unique Growth Pathway in Solution-Solid-Solid Nanowires: Cubic to Hexagonal Phase Transformation.

Solution-solid-solid (SSS) nanowires can be catalyzed by superionic Ag2S via ion diffusion. Here, we synthesize ZnS nanowires of the wurtzite crystal structure and heterostructures via a low-temperature growth pathway. Single-crystalline ZnS nanowires were produced by varying reaction time and temperature (120-200 °C) via thermal decomposition of a single-source precursor, Zn(DDTC)2. A phase transformation (zinc blende → wurtzite) was observed during the synthesis with a three-step growth pathway proposed. Temperature-controlled phase transformation facilitates oriented attachment into a 1D nanowire, followed by helical epitaxial and lateral growths during ripening. Additionally, the CdS-ZnS heterostructured nanowires can be obtained after introducing the Cd(DDTC)2 precursor. ZnS nanowires of defined diameters (5-10 nm) are served as backbones to grow heterostructures of ternary semiconductors with multicolor photoluminescence (450-800 nm). Structural and optical characterizations (PL, 2D PLE, and TCSPC) are investigated to confirm origins of broadband emission from multiple lifetimes (0.5-12 ns) for exciton recombination in heterostructures. Our study demonstrates this unique growth pathway for SSS nanowire synthesis under mild, facile, and atmospheric conditions.