Size-dependent Luminescence of Colloidal ZnSe Quantum Dots

ZnSe quantum dots of three narrow size distributions are prepared through an environmentally friendly chemical route. Then the samples are systematically characterized by UV-Vis absorption spectroscopy and transmission electron microscopy. UV-Vis absorption spectra reveal blue shift of 0.56 eV, 0.19 eV and 0.02 eV respectively indicating strong quantum confinement while transmission electron micrograph displays images of ZnSe quantum dots in the samples in the ranges 2-5 nm, 3-7 nm and 4-8 nm respectively. Then optical emission is studied by fluorescence and electroluminescence spectroscopy. Both the luminescence studies are in good agreement with one another with output peak in and around violet-blue region. Hence, ZnSe quantum dots can be used as efficient LED with better compatibility and faster response.