Optical and photocatalytic properties of ZnO:Mg film grown by spray pyrolysis

Abstract

We study the effect of high Mg impurity in ZnO film grown by spray pyrolisis for photocatalytic applications. The films were grown on the glass substrate for a very short time (10 min). As a result, pure ZnO film has a nanorice structure with a length of ~ 207 nm, as observed by scanning electron microscopy. By inserting the Mg impurity of ~ 32 at.%, the length of the particle decreased to 90 nm. However, this sample with the high Mg content still exhibits a hexagonal wurtzite structure, as shown by the X-ray diffraction pattern. It was also found that the impurity widens the optical band from 3.20 eV to 3.22 eV, possibly due to the alloying effect. Furthermore, the photocatalytic studies reveal that the ZnO exhibits high degradation efficiency under UV light. By adding Mg impurity, the degradation rate decreases by about 2.93% compared to pure ZnO. After 3 days of exposure, the ZnO and ZnO:Mg demonstrated photocatalytic activity, with a degradation efficiency of 95.33% and 94.17%, respectively. So this result is vital in developing low-cost photocatalytic materials by carefully choosing the type and concentration of doping.