具有强电磁共振反射峰的光子晶体构筑及其对上转换发光材料的双重调控

The single bandgap of artificial three-dimensional photonic crystal make it only can manipulate light propagation with single band. Considering the features that the microspheres with refractive index from 2.0-3.0 have strong electric and magnetic resonances in the visible region and the photonic crystals built by these spheres have strong bandgap, in this project, spheres of this kind will be adopted to build photonic crystals to realize strong bandgap and double reflective peaks. First, using polyacrylic acid containing charges as ligand, monodisperse TiO2、ZnO、CeO2 etc. spheres with high surface charge density are proposed to be synthesized by controlling the nucleation and growth process. These spheres are used as building blocks to fabricate photonic crystals and their double reflective peaks can be tuned by changing the diameters or refractive index of spheres. The relationship between the refractive index of soheres and the strength of two reflection peaks of photonic crystals will be established by investigating their reflection spectra. Upconversion nanoparticles such as NaYF4：Yb3+,Er3+ is planned to co-assembly with these spheres, and the double refractive wavelength will be tuned by controlling the diameter and refractive index of the microsphere to make the matching of them with the emissions of upconversion materials. Hence, the two emissions are supposed to selectively enhanced, inhibited and wavelength shifted and realize the single band strong emission and tunable color output, which will facilitate their application in display field.

针对目前人工三维光子晶体只有一个反射峰，只能对单一波长的光进行调控的问题，本项目利用折射率在2.0-3.0的微球在可见光区的强电磁共振反射和该类微球组成光子晶体具有强带隙的特点，拟采用该类微球组装光子晶体，实现具有强带隙、双反射峰光子晶体的构筑。首先采用聚丙烯酸等含有电荷的聚合物为配体，通过对成核和生长过程的控制合成粒径可调的单分散TiO2、ZnO、CeO2等微球；利用所得微球构筑三维光子晶体，通过控制微球的粒径和选择折射率不同的材料调控其电磁共振反射峰和光子带隙的波长，建立微球折射率与反射峰宽度和强度的关联；将该类微球与上转换纳米粒子共组装为复合光子晶体，通过调控光子晶体的双反射峰与上转换发光材料两个发射峰能级匹配，对上转换发光材料的发射光进行进行增强、抑制或光谱位移，最终实现单峰强发射和多色输出，为其在显示领域的应用奠定基础。

针对目前人工三维光子晶体只有一个反射峰，只能对单一波长的光进行调控的问题，本项目构筑了具有双反射峰的三维光子晶体结构。首先合成粒径均匀、可调的单分散ZnS、CdS、TiO2、ZnO等微球，利用其高折射率的特点，以其为结构单元构筑的三维光子晶体不但具有强的光子带隙反射峰，同时具有基于米氏散射的电磁共振反射峰；利用所得微球构筑三维光子晶体，通过控制微球的粒径和选择折射率不同的材料调控其电磁共振反射峰和光子带隙的波长，建立微球折射率与反射峰宽度和强度的关联；将具有双反射峰的光子晶体与上转换纳米粒子共组装为复合光子晶体，通过调控光子晶体的双反射峰与上转换发光材料两个发射峰能级匹配，实现了对上转换发光材料的发射光进行进行增强、抑制或颜色调节，最终实现单峰强发射和多色输出，为其在显示领域的应用奠定基础。