a College of Materials Science and Engineering, Yangtze Normal University, Chongqing 408100, PR China

^bSchool of Mechatronic Engineering, Guangdong Polytechnic Normal University, Guangzhou 510665, PR China

Compared to pure TiO2, Lu-doped TiO2 shows enhanced photocatalytic performance in the visible light range. In order to investigate the influence of Lu doping contents on optical properties ofLu-doped TiO2, we conducted first-principle on TiO2 with different contents of Lu doping. The results indicate that as the contents of Lu increases, the band gap of Lu-doped TiO2 gradually decreases. Within the visible light range, Lu-doped TiO2 exhibits an expanded absorption band ranging from 450 nm to 600 nm. Furthermore, when the Lu

contents reaches 9.09 at%, the absorption intensity shows a higher value between 700 nm

and 800 nm. Lu-doped TiO2 demonstrates a low reflectance in the visible light region, with the maximum reflectance occurring in the infrared region at approximately 65%. The calculated dielectric constant results suggest that the probability of electronic absorption of photons in Lu-doped TiO2 initially decreases and then increases with an increase in Lu contents.