Sol-gel synthesis of cuprous halide nanoparticles in a glassy matrix and their characterization

Abstract

A sol-gel route to synthesize semiconductor cuprous halide CuX (X = Cl, Br) nanoparticles in a glassy matrix has been developed. Cu2O and HCl or HBr were used as the precursors for CuX and the matrix was prepared from 3-glycidoxypropyl trimethoxysilane (GPTS)/tetraethoxysilane (TEOS). Samples were dip-coated and cured either by ultraviolet (UV) irradiation at a temperature of 150 degreesC or in an oven at temperatures of 150-250 degreesC. Thin films (thicknesses 0.7-1.0 mm) containing cubic CuCl and CuBr nanoparticles with diameters ranging from 4-16 nm and 2-28 nm, respectively, were obtained. The ultraviolet-visible (UV-Vis) absorption spectra recorded at room temperature exhibited peaks at 371 and 379 nm for CuCl and at 410 and 391 nm for CuBr, corresponding to the Z(1,2) and Z(3) excitons respectively. X-Ray diffraction patterns showed the characteristic (111), (220) and (311) peaks of cuprous halides. High resolution transmission electron microscopy (HR-TEM) characterization proved that the lattice plane spacings correspond to copper halide nanocrystals.