金红石TiO_2基质中[MoO_4]^(2-)基团的上转换发光

Near-Infrared-to-Visible Photon Upconversion of [MoO_4]2- Complexes Doped in Rutile Titania

在978nm激光二极管的激发下,Mo掺杂的TiO_2材料表现出很强的宽带上转换发光,该发光来源于[MoO_4]^(2-)基团的激发态~3T_1,~3T_2能级到基态~1A_1能级的电子跃迁,X射线衍射表明样品为金红石单一相,红外吸收光谱证实了[MoO_4]^(2-)的存在,由光电子能谱推测体系中还含有低价态的Mo离子,它们提供了上转换得以进行的中间态,高温下的氧化还原处理会改变低价Mo的数量,从而严重影响样品的发光行为。

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 3Ti, 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.