Synthesis of Al-doped ZnO nanomaterials with controlled luminescence

Due to the combination of interesting piezoelectric, electric, optical and thermal properties ZnO-doped nanomaterials are of high interest for multifunctional applications in gas sensors, ultrasonic oscillators or transparent electrodes in solar cells. Their implementation and utilisation is strongly dependant on the microstructure and surface nanochemistry characteristics. New processes for the synthesis and sintering are required to control and optimize the chemical composition, component distribution, crystalline and grain sizes. We present the results on the synthesis of zinc oxide powders with different Al content by two different procedures: hydrothermal route and evaporation–condensation in a solar furnace.The influence of the synthesis parameters on the chemical and microstructural characteristics of nanophases synthesized in the two methods has been systematically studied using chemical methods, XRD, BET, picnometric density, SEM and TEM. The combination of the two methods is demonstrated to be a powerful way to obtain nanomaterials with controlled composition and morphology that could not be successfully realised using classical routes. Al doping leads to a lower material density and to a smaller grain size. The first results on the luminescence properties of Al-doped ZnO nanopowders are also presented.