W-LED用Sn2+掺杂光转换玻璃和微晶玻璃的荧光性能调控与机理研究

Due to their broadband visible emission, Sn2+-doped light-converting luminescent glass and glass ceramics (GCs) have great prospects in the field of light-converting materials for single-phase W-LED excited by UV chip. However, Sn2+ ion is unstable and susceptible, and is easily oxidized into Sn4+, resulting in the low emission efficiency and uncertain spectral performance, which restricts its applications. To obtain high efficient and tunable broadband emissions of Sn2+, this project will be aimed at the effective control of the valence state, excitation and emission spectra of Sn2+, and studied systematically on the luminescent properties and structural characteristics of Sn2+ doped multi-component glass and GCs by a series of structural characterization and spectral theoretical analyses. Simultaneously, the relationship between glass structure and luminescence will be also revealed. By adjusting the species and concentration of glass network former, intermediator and modifier, modulating glass optical basicity and controlling crystallization process, the valence state and luminescent properties of tin ions can be modified. In the meanwhile, the luminescent mechanism will be also clarified. The excitation and emission wavelength of Sn2+ can be tunable in a large range, covering 250-400 and 350-600 nm, respectively. The energy transfer mechanism between Sn2+ and rare earth (RE)/transition metal (TM) ions will be also studied. The near white light emitting Sn2+/RE/TM co-doped light-converting glass and GCs can be obtained by adjusting the concentration of RE/TM ions. The successful implementation of this project will exhibit important practical value and theoretical significance, and can provide a new idea for the design of novel light-converting glass materials for W-LED.

Sn2+掺杂光转换玻璃和微晶玻璃(GC)具有宽带可见发光，在紫外芯片激发单一基质W-LED用光转换材料领域具有广阔前景。但亚锡不稳定，易被氧化成四价，导致其发光效率低且光谱性能不确定，制约了其应用。本项目拟有效调控Sn2+价态、激发和发射光谱为目标，以Sn2+掺杂多组分玻璃和GC为研究对象，通过一系列结构表征和光谱理论分析等手段，揭示其结构与荧光特性之间的构效关系，以期获得Sn2+高效可调发光。具体地，通过调控玻璃网络形成体、中间体、修饰体、光学碱度和析晶过程改变玻璃结构，调控锡离子价态和荧光，并阐明其机理，实现Sn2+在250-400nm可调激发和350-600nm可调发射；研究Sn2+与稀土(RE)/过渡金属(TM)离子之间的能量传递机制，调节RE/TM浓度，以期获得近白光发射Sn2+/RE/TM玻璃。本项目的顺利实施具有重要实用价值，可为设计新型W-LED用光转换玻璃提供新思路。

LED因具有高效节能、绿色环保、使用寿命长等优点，逐渐成为照明、显示、背光源等领域的主要光源。但其封装过程中使用的环氧树脂，热稳定性差，易受器件高温影响而老化变黄，易使LED器件显示指数降低、色温升高、稳定性变差、寿命变短等问题。因此，急需开发高效的、热稳定性好的新型固态照明用W-LED技术。. 光转换玻璃，具有透过率高、化学、机械和热稳定性好、对激活离子(如RE、TM离子)溶解度大、制备技术简单等特点，被认为是极具价值的LED用先进光功能材料：光转换玻璃用于LED时，无需树脂封装，可避免环氧树脂老化导致的LED光学参数和性能降低问题；另外，若选用紫外芯片作为激发源，就可避免蓝光芯片和荧光玻璃衰减速率不同造成的色差。因此，紫外芯片激发W-LED用光转换玻璃有望成为一种新型的固态照明光源。. Sn2+离子具有[Kr] 4d105s2的电子组态（ns2组态），基态能级为[Kr] 4d105s2，激发态能级为[Kr] 4d105sp，能够呈现出较强的可见宽带发光。Sn2+掺杂的光转换玻璃和微晶玻璃在紫外芯片激发单一基质W-LED用光转换材料领域具有广阔的发展前景。为实现Sn2+离子宽带可调高效的发光，本项目开展并取得了如下工作：获得了能够使Sn2+稳定存在的新型透明光转换氧氟化物玻璃和微晶玻璃，实现了Sn2+激发(220-350 nm)和发射(300-725 nm)宽带可调；通过调控玻璃中晶体场环境(晶相)来调节玻璃结构，揭示了晶体场与Sn2+发光特性之间的关系；获得了Bi+和Sn2+掺杂光转换玻璃，同时揭示了光学碱度、玻璃网络结构、配位场环境与发光中心荧光特性之间的关系，阐明了发光中心的发光机理，补充拓展了局域过剩电荷模型；获得了Sn2+、Dy3+、Mn2+共掺杂光转换玻璃，阐明了其能量传递机理和发光机制，实现近白光发射；另外还研究了Sn2+、Tb3+掺杂玻璃的闪烁性能，以及温度传感材料基于Eu3+/Tb3+和Bi3+/Eu3+荧光强度比的光温度灵敏特性。. 总之，本项目研究结果表明Sn2+掺杂光转换玻璃和微晶玻璃在W-LED照明显示领域具有潜在的应用价值，且本项目中提出的发光机理、荧光特性与玻璃结构关系对其他低价态发光中心的价态和荧光调控具有指导意义。.