Synthesis and Characterization of CuZnSe2 Nanocrystals in Wurtzite, Zinc Blende and Core-Shell Polytypes

CuZnSe2 (CZSe) is an important ternary semiconductor comprised of earth-abundant elements with a suitable bandgap for visible light absorption and structural/stoichiometric versatility that make it a promising candidate for photovoltaic applications. Here we report the controlled synthesis of this compound copper chalcogenide in nanocrystal form using a colloidal hot-injection approach. The as-synthesized CZSe nanocrystals are nearly monodispersed with a typical size of ~15 nm. Furthermore, we demonstrate control over the crystal phase to occur either as wurtzite (WZ) or zinc blende (ZB) as a function of the presence and absence of phosphine-based ligands. A major emission peak was observed at ~1.7 eV using low-temperature photoluminescence (PL), ranging from 30 K to 200 K. Additionally, we demonstrate the ability to extend this synthetic protocol to form a polytype structure comprised of a ZB core with a WZ shell.