Near-Infrared-to-Visible Photon Upconversion of [MoO4]2- Complexes Doped in Rutile Titania
金红石TiO2基质中[MoO4]2-基团的上转换发光

Mo-doped titania excited by a 978nm diode laser exhibits a visible broadband emission which can be controlled by high-temperature chemical redox. The luminescence has been assigned to the transitions from the excited states 3T1, 3T2 to the ground state 1A1 of the MoO4]2- radicle. FTIR spectrum confirms the presence of the MoO4]2- complexes, while XPS measurement suggests the concurrent existence of lower valent Mo species. The intermediate states available for upconversion are supposed to be related to the lower valent Mo species through which the external chemical redox modifies the luminescence.