Green synthesis of ZnSe quantum dots using in-situ synthesised sodium selenide
Single-step green synthesis of zinc blende ZnSe quantum dots (QDs) is performed using sodium selenide and zinc stearate. The present method is non-toxic and is considered reasonably green route where stearate ions released during the reaction act as surfactant. The size quantisation effect is revealed by blue shifted absorption bands with a band-gap energy of ~2.9 eV with respect to bulk ZnSe band-gap of 2.7 eV. Photoluminescence measurement with FWHM <80 nm revealed trap state emission. Broadened XRD pattern confirmed cubic (zinc blende) crystal structure of ZnSe. The particle size was estimated to be about 5 nm from the XRD line broadening, which matched well with TEM analysis.