Er3+-Yb3+体系上转换红光激发路径的研究

Er3+-Yb3+体系是公认的最优良的上转换发光体系之一，能产生上转换绿光和红光。申请人在Y2O3:0.2%Er3+/10%Yb3+中发现一个基于Er3+、Yb3+离子间往返能量传递的红光激发新路径，并且该路径对产生上转换红光起主导作用。还观察到大能量失配下Yb3+的能量传递向Er3+ 4I13/2能级的直接有效布居，表明这个通常被忽视的过程对红光有显著贡献。本项目拟选择几种Er3+-Yb3+共掺杂的高效上转换发光材料为对象，利用能量传递和发光动力学实验方法，研究上述新路径对红光的贡献程度及其与Er3+、Yb3+掺杂浓度和基质声子能量的依赖关系，完善Er3+-Yb3+体系上转换红光的现有激发机制、重新认识激发过程和主要激发路径，并为设计基于Er3+-Yb3+体系的高效上转换发光材料提供理论指导。

The Er3+-Yb3+ system is recognized as one of the excellent systems of upconversion luminescence and it shows a green emission and a red emission. The applicant previously found a new excitation route for the red emission in Y2O3:0.2%Er3+/10%Yb3+. The new route is a process of forward-backward energy transfer between Er3+ and Yb3+ and it makes the main contribution to the red emission. The applicant also observe that the Er3+ 4I13/2 state is effectively populated vs energy transfer from Yb3+ in case of a large energy mismatch, indicating that this long neglected process can make a remarkable contribution to the red emission. In this project, we plan to select Er3+ and Yb3+ co-doped efficient upconverting materials as samples and study the role of the new excitation routes in the excitation of the red emission as a function of doping concentrations and phonon energies. This study is helpful to improve the excitation mechanism of the red emission and reunderstand the excitation processes and the main excitation route, and provide theoretical guidance for the design of efficient upconverting materials based on the Er3+-Yb3+ system.