Yb3+/Mn2+共掺透明玻璃陶瓷可调宽带上转换发光研究

Yb3+/Mn2+ activated broadband upconversion luminescence, is based on a novel upconversion behavior in which wavelength-tunable upconversion luminescence can be realized via the aggregation coupling of Yb3+-Mn2+ ions under 980 nm laser excitation. So far, such rare earth/transition metal ions activated upconversion luminescence is limited to a few cases in phosphors and nanomaterials, while has been rarely observed in transparent hosts. Transparent glass ceramics, which benefit from the excellent luminescent properties of nanocrystals in combination with the high physic-chemical stability of glass matrix, are considered as most promising host materials. This project aims at developing Yb3+/Mn2+ co-doped glass ceramics which display wavelength-tunable upconversion luminescence from visible to near infrared region, via controlling the precipitated nanocrystal phase and the doping concentrations of Yb3+/Mn2+ ions. The research emphasis focuses on studying the effect of type and structure of the precipitated nanocrystals in glass ceramics as well as the concentration of dopants on the upconversion luminescence properties. By investigating the correlation between nanocrystal phase and aggregation coupling of Yb3+-Mn2+, and upconversion luminescence, it is expected to establish a luminescence physical model which in combination with the spectral signature, can be utilized to reveal the underlying upconversion mechanism. This proposal is of paramount importance to understand the novel upconversion process in glass ceramics and open up new possibilities for the practical applications of such nanocomposite upconversion materials.

Yb3+/Mn2+激活的上转换宽带发光，是一种新的上转换发光现象，即在980 nm激发下通过Yb3+-Mn2+聚集耦合作用实现上转换发光。目前关于这种上转换发光的研究几乎都集中在粉体或纳米材料，在透明光学材料的研究中却鲜有开展。透明玻璃陶瓷作为一种兼具了纳米晶相优异发光性能和玻璃相良好物化特性的纳米复合材料，被认为是极具发展潜力的基质材料。本项目拟研制Yb3+/Mn2+共掺具有高效上转换发光的新型透明玻璃陶瓷，通过控制合适纳米晶相的析出和Yb3+/Mn2+掺杂浓度，实现玻璃陶瓷中可见—近红外的可调控发光。重点研究玻璃陶瓷中纳米晶体类型、晶体结构、离子掺杂浓度对上转换发光的影响。探明晶相结构与Yb3+-Mn2+聚集耦合及上转换发光的关联，建立发光物理模型，进一步结合光谱特征揭示其上转换发光机理。本项目研究对拓展玻璃陶瓷在上转换发光领域的应用和深入认识其发光机理具有重要的指导意义。

近年来随着激光和纳米新型技术的飞速发展，基于上转换光功能材料在激光器、太阳能电池、生物荧光成像、三维显示和防伪等领域的应用优势日益凸显，并且已成为当前发光领域的研究前沿和热点之一。稀土离子激活上转换发光材料在波长选择和带宽上均存在局限性，一定程度上制约了其发展及应用。利用过渡金属Yb3+/Mn2+共掺于同一基质中在商用980 nm激光器泵浦下获得上转换发光是近年来发现的一种新的上转换发光现象，该方法可实现可见到近红外区域灵活高效的上转换宽谱发射，有望弥补稀土发光的不足，在可调谐激光器、全光谱太阳能电池、多色显示及高分辨生物荧光成像等领域发挥其应用价值。.本项目针对当前Yb3+/Mn2+激活上转换发光材料体系研究相对匮乏及上转换发光过程、光谱调控规律尚不清晰现状，提出以透明玻璃陶瓷为基质载体，研究玻璃陶瓷可见到近红外区域上转换宽带发光及其调控机理，拓展玻璃陶瓷材料在上转换发光领域应用前景。项目组成功合成了Yb3+/Mn2+掺杂双晶相（γ-Ga2O3/β-YF3）纳米氟氧化物玻璃陶瓷，通过析出不同的晶相，实现了480~720 nm光谱范围内连续双宽带可调控的上转换发光；在含钙钛矿氟化物KMgF3纳米晶玻璃陶瓷中，通过控制析晶度，同样也获得了可调控的宽谱上转换发光；可控地析出了Yb3+/Mn2+掺杂α/β-Zn2SiO4纳米复合玻璃陶瓷。详细阐述了离子浓度、热处理温度/时间、晶体结构、对宽带光谱的影响和调控机理，揭示了不同材料体系中Yb3+与Mn2+聚集作用方式、格位占据与上转换发光过程的对应关系；进一步合成了基于Tm3+/Yb3+/Mn2+掺杂的透明玻璃陶瓷，实现了可调节的上转换白光输出，探究了稀土离子Tm3+与Yb3+-Mn2+对激活中心之间的能量传递过程及上转换发光机制。.我们的研究成果拓宽了上转换发光光谱，为深入认识过渡金属上转换发光机理提供了理论支撑，同时对拓展透明玻璃陶瓷材料在可调谐激光器、太阳能电池、多色荧光显示等光电子领域的应用具有指导意义。