The effect of surfactants and precursors on the structure and properties of ZnS:Cu nanocrystalline particles

Doped ZnS materials exhibit excellent optical and electrical properties, making them a superior material for alternating current (AC) thin film electroluminescent devices, solar panels, light-emitting diodes, laser diodes and other luminescent device designs and fabrications. This study involves the hydrothermal synthesis of nanocrystalline Cu-doped ZnS materials without a surfactant and using two surfactants – hexadecyltrimethylammonium bromide (HTAB) and sodium dodecyl sulfate (SDS). The structure, morphology and elemental content of the synthesized nanopowders were characterized by X-ray powder diffraction, X-ray absorption spectroscopy (XAS), scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDX) techniques, while the optical properties were studied by photoluminescence (PL) spectroscopy. The sizes of the nanocrystallites in all the synthesized samples were below 20 nm. XAS results suggest that Cu ions substitute Zn ions in cubic zinc blende ZnS structure and are located in a locally distorted environment. The addition of a surfactant allows control of the morphology of the particles and their photoluminescent properties.