title: Sensitized luminescence of Sm3+,Eu(3+)-codoped TiO2 nanoparticles.
abstract: Sm3+,Eu(3+)-codoped TiO2 nanoparticles were prepared by a facile sol-gel-solvothermal method. Sm3+ and Eu3+ were successfully incorporated into a TiO2 lattice and resulted in intense emission lines with resolved crystal-field splitting, in spite of a large mismatch in ionic radius between trivalent lanthanides (Ln3+) and Ti4+. The intense sensitized emissions of Sm3+ and Eu3+ ions by TiO2 host were obtained at room temperature. In this case, Sm3+ also acts as a bridge to transfer energy from TiO2 host to Eu3+ ions, which was not observed in Eu(3+)-doped TiO2 nanoparticles. In comparison with direct excitation of lanthanide ions, the luminescence lifetimes of 4G5/2 of Sm3+ and 5D0 of Eu3+ were observed to be significantly prolonged upon excitation above TiO2 band-gap. A sensitization mechanism to illustrate the energy transfer from TiO2 to Sm3+ and Eu3+ was proposed based on the optical behaviors of the codoped nanoparticles.
authors.affiliation: Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China.
authors.forename: Wenqin
authors.initials: W
authors.lastname: Luo
authors.forename: Renfu
authors.initials: R
authors.lastname: Li
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Liu
authors.forename: Xueyuan
authors.initials: X
authors.lastname: Chen