Structure And Luminescence Properties Modulaton Of Rare Earth Doped Silicate Phosphors

White light-emititng diodes（w-LEDs） have been widely used in lighting and display fields, and considered to be a fourth-generation lighting source owing to their environmentally friendly character, high efficiency, long lifetime, and small volume. Currently, phosphor convertersion method is the most common and popular way to fabricate white LEDs. As a key component, phosphors have an important influence on the properties and parameters of the white LEDs devices, such as correlated color temperature（CCT）, light conversion efficiency, color rendering index（CRI）, and so on. Hence, we should pay much attention to find new phosphors in order to improve the performance of w-LEDs.In this paper, a mineral-insprired method has been used to discvover the new phosphors and enable the photoluminescence tuning. Our present work focuses on the research and development of three silicate compounds namely Mg₂Al₄Si₅O₁₈, BaY₂Si₃O₁₀ and Ba₂Gd₂Si₄O₁₃ host, and the host modification and energy transfer strategies have been used to realize the photoluminesenc tuning and optimize the luminescence properties. The relationship between the crystal structures and luminescence properties of the phospors have been discussed. The main contents are as follows:（1） MxMg₂Al_4+xSi₅-xO₁₈:Eu²⁺（M = K, Rb） solid solution phosphors were synthesized through introducting M+ ions into the void channels of Mg₂Al₄Si₅O₁₈. By gradually introducing M+ ions, there is a red-shift of emission spectra, and the emission intensities, full width half maximum values, thermal stability and QE were greatly improved compared with Mg₂Al₄Si₅O₁₈:0.03Eu²⁺.（2） According to different cations crystallographic sites in BaY₂Si₃O₁₀, several kinds of rare earth ions were doped in BaY₂Si₃O₁₀ host in order to achieve energy transfer and color-tunable phosphors. The energy transfer between Ce³⁺ and Tb³⁺, Tb³⁺ and Eu³⁺ were systematically studied, and Ce³⁺-Tb³⁺-Eu³⁺ energy transfer process was put forward, in which Tb³⁺ was performed as the energy transfer bridge. In addition, a single host white-emitting phosphor BaY₂Si₃O₁₀:Tm³⁺,Dy³⁺ were prepared via Tm³⁺-Dy³⁺ energy transfer. The crystal structure, luminescent properties and energy transfer mechanism were investigated in detail.（3） A series of color-tunable Ba₂（Gd,Tb）₂Si₄O₁₃:Eu solid solution phsphors were prepared. The Tb³⁺ can not only form the iso-structural phase in the Ba₂Gd₂Si₄O₁₃ host, but they can be also used to realize the energy transfer between Eu²⁺ and Eu³⁺.