Ultrafine gahnite (ZnAl2O4) nanocrystals: Hydrothermal synthesis and photoluminescent properties

We demonstrate a facile but efficient hydrothermal method for the preparation of ultrafine gahnite (ZnAl2O4) nanoparticles without post-treatment by varying the reaction parameters, including reaction temperature, reaction time and basic source. These parameters were systematically investigated in terms of XRD and TEM techniques. The experimental results revealed that the reaction temperature and basic source play the crucial roles in obtaining ZnAl2O4 sample, whereas the reaction time has minor influence. Significantly, we successfully prepared ZnAl2O4 sample at 180 °C, using urea as the basic source, which is the lowest reaction temperature ever reported for the preparation of ZnAl2O4. In addition, the ZnAl2O4 samples prepared under various conditions exhibit strong emission at room temperature.