Ir(ppy)_3分子的磷光发射温度依赖和磁场增强效应  

Influence of Temperature and Magnetic Field on Phosphorescence from Ir(ppy)_3

作　　者：余书楷 张超[1] 苏付海[1] 徐文[1,2] 

机构地区：[1]中科院合肥物质科学研究院材料物理重点实验室,安徽合肥230031 [2]云南大学,云南昆明650091

出　　处：《稀有金属材料与工程》2015年第11期2923-2926,共4页Rare Metal Materials and Engineering

摘　　要：应用磁光光谱技术,测量并研究了溶解在四氢呋喃（tetrahydrofuran,THF）中Ir（ppy）3分子的磷光发射特性随温度和磁场的变化规律。发现在2.2 K时可见光波段Ir（ppy）3有两个磷光发射峰,分别位于547.70和515.18 nm。这是由系统的金属到配位体电荷转移态（3MLCT）中两个激发态到基态的光跃迁引起。改变温度可以改变三重态中亚能级I、Ⅱ和Ⅲ上的电子分布,使得磷光发射峰的强度在10 K时发生反转,并且光谱发射强度在20300 K间随温度增加而减弱。在强磁场作用下,Ir（ppy）3在2.2 K温度下的磷光发射强度随磁场强度增大而增强。外加磁场能改变3MLCT态的三个亚能级上的电子跃迁几率,从而能增加磷光发射强度。The basic features of phosphorescent emission from Ir（ppy）3（ppy=2-phenylpyridinate）,dissolved in THF,were investigated by a magneto-luminescence technique.It is found that there are two peaks in the phosphorescent spectra in visible region from 2.277 K.They are located at 547.70 nm and 515.70 nm wavelength.This is due to radiative electronic transition from two substates in 3MLCT structure to the ground state of Ir（ppy）3.Changing temperature can vary electron distribution and life-time on different substates in the3 MLCT structure of Ir（ppy）3.Thus,we can observe a strong dependence of the phosphorescent spectrum on temperature.Furthermore,we find that the intensity of phosphorescent emission from Ir（ppy）3 increases with magnetic field at 2.2 K.The presence of the high magnetic field can alter the electronic states and,thus,modulate the electron distribution and transition possibility for substates in 3MLCT.As a result,the phosphorescence emission from Ir（ppy）3 can be enhanced by the presence of the magnetic field.

关 键 词：Ir(ppy)3 温度 磁场 

分 类 号：O627.8[理学—有机化学]