Characterization and optical properties of mechanochemically synthesized molybdenum-doped rutile nanoparticles and their electronic structure studies by density functional theory
H. Maleki‐Ghaleh, Mohammad Sadegh Shakeri, Ziba Dargahi, Majid Kavanlouei, H. Kaveh Garabagh, Ehsan Moradpur‐Tari, Amin Yourdkhani, Ali Fallah, Ali Zarrabi, Bahattin Koç, M. Hossein Siadati
Abstract
The optical and electronic properties of molybdenum (Mo) doped rutile TiO 2 prepared by the mechanochemical method were studied both experimentally and using density functional theory (DFT). The synthesized nanoparticles were characterized by XRD , TEM , EDS-MAP, and XPS . The XRD results showed the successful incorporation of Mo in the rutile crystal lattice . High-resolution TEM images illustrated a decreasing trend in the (110) d-spacing for samples doped up to 3 at%. The shift toward higher binding energies in the XPS spectra was due to the higher oxidization tendencies of Mo 5+ and Mo 6+ substituted in Ti 4+ sites. The optical behavior of samples was examined by UV–Vis and photoluminescence spectroscopy. The bandgap energy value of rutile was reduced from 3.0 eV to 2.4 eV by 2 at% Mo doping. The DFT calculations showed a reduction of bandgap energy value of rutile to 2.35 eV with 2 at% Mo, which is in harmony with the experimental results. The creation of energy states below the conduction band because of Mo doping was identified as the reason for reducing the bandgap energy and photoluminescence emission of rutile.