Morphology, photoluminescence and gas sensing of Ce-doped ZnO microspheres

Ce-doped ZnO microspheres were solvothermally prepared, and their microstructure, morphology, photoluminescence, and gas sensing were investigated by X-ray diffractometer, field emission scanning electron microscopy, transmission electron microscopy, fluorescence spectrometer and gas sensing analysis system. The results showed that the Ce-doped ZnO microspheres were composed of numerous nanorods with a diameter of 70 nm and a wurtzite structure. Ce-doping could cause a morphological transition from loose nanorods assembly to a tightly assembly in the microspheres. Compared with pure ZnO, the photoluminescence of the Ce-doped microspheres showed red-shifted UV emission and an enhanced blue emission. Particularly, the Ce-doped ZnO sensors exhibited much higher sensitivity and selectivity to ethanol than that of pure ZnO sensor at 320 °C. The ZnO microspheres doped with 6% Ce (mole fraction) exhibited the highest sensitivity (about 30) with rapid response (2 s) and recovery time (16 s) to 50×10−6 ethanol gas.