Sol–gel synthesis of cuprous halidenanoparticles 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 °C or in an oven at temperatures of 150–250 °C. Thin films (thicknesses 0.7–1.0 µm) 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 Z₃ 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.