ZnS and ZnO nanocomposite for near white light tuning applications

There is currently an increased interest in demonstrating white light emitting devices that exhibit a higher energy efficiency compared to the ubiquitous incandescent sources and that are at the same time cost-competitive as well as compatible with a mass-production environment. Under the aforementioned stringent constraints, photoluminescent quantum dots can be considered a suitable option to demonstrate said white light emitting constructs. To this end, the present report discusses the synthesis and characterization of nanoparticles of zinc oxide (ZnO) and zinc sulphide (ZnS) that exhibit Stokes shift effects and optical properties of light absorption in the UV range (~340 nm) and luminescent capabilities obtaining peaks centered in 525 nm and 440 nm, respectively. Colloidal mixtures of these nanostructures were made with different volumetric ratio in order to achieve a near white color emission. Photoluminescence studies of the mixtures were carried out and a chromaticity diagram was made to localize and identify a trend in the luminescent variations of the samples within the International Commission on Illumination (CIE) diagram. The experimental results indicate that quantum dots could be a viable alternative for high-efficiency and cost-competitive white light emitting devices.