DEVELOPMENT OF OXIDE NANOPHOSPHORS FOR DISPLAY APPLICATIONS

Abstract

Nanoparticles have indicated unique properties in materials, which have been different from bulk materials by a reduction in volume and an increase in the specific surface area. Properties such as band gap engineering of nanoparticles by quantum confinement and increase in reactivity due to increased specific surface area have been investigated by researchers in various fields. These materials could be utilized for light-emitting devices, fluorescent materials, catalysts and paint. Semiconductor nanoparticles are expected to have uses in bio-imaging, displays and fluorescent lights because of the controllability of both the excitation and the emission wavelengths by quantum size effects. In these applications, bio-imaging has been studied widely because of the potential realization of personalized medicine, genomic drug discovery and preventive medicine. The research of cadmium series quantum dots, which show visible fluorescence, has led to the development of a nanosize marker for bio-imaging. However, the toxicity of cadmium to the human body has been a concern. ZnO has been one of the most promising materials for opto-electronic devices, including transparent conductive films, light emitting diodes and photocatalysts. Moreover, it has been chemically and optically stable and has a low toxicity, its use as a fluorescent label for bio-imaging has been anticipated. It is apparent that the full potential of the as-prepared nanostructures will only be realized when materials are not only synthesized in large quantities with reproducible size, shape, structure, crystallinity, and composition but also prepared and assembled using green, environmentally friendly methodologies The sol-gel and micro-emulsion methods are versatile, practical and low cost methods for nanostructures, but they involve a final calcination or annealing step at high temperature; thus they cannot be considered to be true low-temperature synthesis methods and it is difficult to control the particle size and morphology. Hydrothermal and solvothermal syntheses are effective for synthesizing nanomaterials and available for many kinds of materials.