Quantum confinement effect of in-situ generated Cu2O in a nanostructured zirconia matrix.

The incorporation of Cu2+ in zirconyl chloride octahydrate sol or solution was used as a precursor for dip coating. This resulted in the in-situ formation of nanostructured Cu20 quantum particles in the zirconia matrix. The size-dependent properties of the Cu20 quantum particles were observed when the films were annealed in the range of 200-600 °C. A red shift of the UV band, ascribed to the transition from the copper d-shells to higher sublevels of the conduction band, was observed in the range of 260-315 nm due to an increase in the nanocrystallite size with increasing annealing temperature. Three types of emissions, blue, green, and yellow, were observed in films of relatively high thickness (around 120-130 nm) due to Wannier-bke excitonic transitions. For films of relatively low thickness (50-70 rim) only green emission was observed. From lifetime measurements of samples annealed at 450°C it may be concluded that the short decay time is bi-exponential in character from ns to ps with the chi-square value of 1.005, which is due to the confinement of Cu2O quantum panicles. [ABSTRACT FROM AUTHOR]