Enhancing persistent luminescence and photocatalytic properties in Ti as a trap center in ZnGa2O4

• Published in: Journal of materials science. Materials in electronics 2017, Vol.28 (2), p.1294-1300
• Main Authors: Huang, Haiju, Wang, Yinhai, Li, Hong, Li, Jun, Hu, Zhengfa, Zhao, Hui, Yi, Shuangping, Wei, Zhigang
• Format: Article
• Language: English
• Subjects: Catalytic activity; Characterization and Evaluation of Materials; Chemistry and Materials Science; Conduction bands; Doping; Luminescence; Materials Science; Optical and Electronic Materials; Optical properties; Phosphors; Photocatalysis; Reflectance; Thermoluminescence
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-016-5658-z

ZnGa 2 O 4 and ZnGa 2 O 4 :Ti phosphors were synthesized by the solid state method, and their persistent luminescence and photocatalytic properties were investigated in detail. The results of this study showed that Ti 4+ doping improved the persistent luminescence properties. Thermoluminescence measurements demonstrated that the trap concentration considerably increased upon incorporation of Ti 4+ ions into the ZnGa 2 O 4 lattice. The traps generated by Ti doping were responsible for improvement in persistent luminescence. Furthermore, photocatalytic activity tests showed that the Ti-doped ZnGa 2 O 4 phosphor exhibited much higher photocatalytic activity than the ZnGa 2 O 4 host. UV–Vis diffuse reflectance spectra demonstrated that Ti-doped ZnGa 2 O 4 shown a higher UV absorption efficiency. A comparison between the density of states of ZnGa 2 O 4 :Ti and ZnGa 2 O 4 revealed that the bottom of the conduction band was modified by Ti doping. Hence, it could be concluded that Ti doping enhanced light harvest capability to generate more electron–hole pairs, and acted as a trap center by decreasing the recombination of photogenerated electrons and holes, resulting in the enhancement of both persistent luminescence and photocatalytic activity.