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 the compound copper chalcogenide in nanocrystal form using a colloidal hot injection approach. Furthermore, we demonstrate control over the crystal phase to occur as either 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 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.