稀土包覆金属纳米核壳结构掺杂液晶的发光调控

Rare earth doped nano-materials have attracted extensive attentions for their excellent photovoltaic performance, and are widely applied in many fields such as color display, white-light LED, lasers and fluorescent labeling . For example, in application of display, the regulation of emission and luminescent enhancement is very important. Hereby, we intend to synthesize core-shell structures that metal nanoparticles are coated by inorganic oxides. By using some methods like grafting to get combination with the rare earth ions, then doped into the liquid crystal to adjust the local surface plasmon resonance(LSPR) peak to match the excied or emission spetra of the rare earth ion emitters and improve the luminescent efficiency. We will change the nano particles parameters such as the size, shape and the thickness to obtain the corresponding LSPR peak and emission intensity. On the other hand, by changing the orientation of the liquid cystal molecules by adjusting voltage, and thus the extinction peaks of the long or short directions of core shell structure, we can make the resonance peaks of nano particles to match well with the excitation and emission peaks so as to adjust the emission spectra and improve the luminescent efficiency.

稀土纳米材料因其优异的光电特性，在柔性显示、白光LED、荧光标记等很多领域应用广泛。在显示技术等实际应用中，调控稀土离子发光、提升发光效率是非常重要的。本项目拟制备以金属纳米粒子为核、以无机氧化物为壳的核壳结构，并通过混合包覆法和嫁接法等方法与稀土发光离子相连接，再掺杂到液晶基质中。一方面通过改变金属纳米结构的大小、形状、长短径纵横比和无机壳的厚度等参数，调控金属纳米结构的局域表面等离子体共振（LSPR）峰位置和强度，另一方面利用向列相液晶的特点，调节液晶盒的外加电压以控制液晶分子的排列状态，改变非对称的稀土包覆金属纳米核壳结构的长径或短径方向的LSPR峰，使LSPR谱与稀土发光离子的激发峰和发射峰有效匹配，从而获得金属纳米粒子到发光离子之间的高效能量传递，实现发光性能的有效调控，提高稀土离子发光效率。

基于局域表面等离子体共振效应，贵金属纳米结构可以通过激发增强或辐射增强的方式调控其周围发光分子的发光特性。同时其调控效果依赖于纳米结构形状、周围环境及发光分子与贵金属纳米结构间距等因素。液晶由于其各向异性可为发光材料提供电压可调以及柔性的周围环境。我们制备了不同尺寸的稀土包覆贵金属纳米核壳结构以及稀土掺杂液晶发光材料，通过施加电压改变液晶分子取向、将稀土发光材料、不同形状贵金属纳米核壳结构与液晶结合等方法，调控了稀土掺杂液晶发光材料的荧光性能。此外，利用样品不同的荧光寿命特性，类比于离合诗方式对数据进行加密储存，探究了其在荧光寿命复用研究中的应用可行性。