Tunable Upconversion Luminescence and Photocatalytic Activity of Ln3+ Doped One-Dimensional NaYF4/Y2Ti2O7TiO2/Bi2MoO6 Hierarchical Structures

Ln(3+) doped NaYF4/Y2Ti2O7/TiO2 (NYT) microfibers were prepared by combining the hydrothermal method with electrospinning technique. And then, Ln(3+) doped NaYF4/Y2Ti2O7/TiO2/Bi-2 MoO6 (NYTB) hierarchical structures were prepared by growing Bi2Mo06:Er3+ nanoparticles on the surface of NaYF4/Y2Ti2O7/TiO2 microfibers. Tunable upconversion luminescence was successfully achieved by adjusting the TiO2 and Bi-2 MoO6:Er3+ contents. The mechanism of upconversion luminescence was investigated in detail. The results indicated that two- and three-photon processes are responsible for populating the S S-4(3/2)/H-2(11/2) levels in Ln(3+) doped NaYF4/Y2Ti2O7/TiO2 and NaYF4/Y2Ti2O7/TiO2/Bi-2 MoO6 , respectively. The BET surface areas of Ln3+ doped NaYF4/Y2Ti2O7/TiO2/Bi-2 MoO(6)increased with the Bi-2 MoO6:Er3+ content increasing. In addition, the photocatalytic activity of Ln(3+) doped NaYF4/Y2Ti2O7/TiO2 and NaYF4/Y2Ti2O7/TiO2/Bi-2 MoO(6)was evaluated by the degradation of rhodamine B aqueous solution under ultraviolet and visible light irradiation.