Synthesis and Characterization of Copper (i) Oxide and Zinc Oxide Quantum Dot Materials and the Development of New Fluorescent Fibre Composites

J.H. Johnston, A.J. Zeller
Victoria University of Wellington, NZ

Keywords: copper oxide, zinc oxide, quantum dots, photoluminescent, fluorescent


New fluorescent composites of Cu2O and ZnO quantum dots with wool and paper fibres for potential use in photoluminescent fabrics, packaging and labelling papers, have been developed. The fluorescent colours can be tuned by varying the particle size of the quantum dot and functionalising the surface. Cu2O quantum dots were synthesised by a wet chemical reduction method to produce nanocubes of about 100 nm size that comprise an assemblage of smaller spherical nanocrystals. Colloidal suspensions are yellow-green in reflected light and red-purple in transmitted light. A sol-gel method was developed to prepare ZnO quantum dots as polycrystalline particles 100 nm - 1µm in the size that comprise agglomerations of small 10 - 12 nm nanocrystals. These are white in ambient light and a fluorescent yellow-orange colour in UV light. This colour can be changed by functionalising the ZnO surface with 18-methyl eicosanoic acid, 8-Hydroxyquinoline (8-HQ) or polypyrrolidone. 8-HQ was used as a chelating agent for ZnO to impart strong white, blue or green fluorescence colours in ZnO - wool and paper fibre composites. The intensity was much higher than for ZnO or Cu2O quantum dots.