Photoluminescence and photodissociation properties of pure and In ₂O₃ doped ZnO nanophases

Pure and doped zinc oxide powders of various grain sizes have been synthesized by sublimation-condensation technique using a solar furnace. The initial powders contained from 0 to 5% mol of In₂O₃. X-ray diffraction technique (XRD) has been used to measure the lattice parameters and the grain size. The Indium concentration in the nanopowders was determined by XPS. XRD showed the formation of the spinel phase Zn₅In ₂O₈ in the micropowders as the concentration of indium exceeded 2.5% mol. In addition, the grain size of nanopowders decreases as the In concentration increases for all considered compositions. The photoluminescence spectra showed a drastic reduction of the exciton bound to a donor and an important broadening of the corresponding line as a result of the In doping. The photocatalytic properties of ZnO and TiO₂ powders were investigated using the Monoluniron as septicide. The results showed that the photodegradation of the molecule was significantly faster when using pure ZnO nanopowder. However, the photocatalytic activity of the ZnO nanopowders was drastically reduced by the In doping.