Energy transfer probability in organic electrophosphorescence device with dopant  

作　　者：代国章 李宏建 潘艳芝 戴小玉 谢强 

机构地区：[1]Department of Applied Physics, Hunan University, Changsha 410082, China

出　　处：《Chinese Physics B》2005年第12期2590-2594,共5页中国物理B（英文版）

基　　金：Project supported by the Excellent Youth Foundation of Hu＇nan Province （Grant No 03JJY1008）, and by the Science Foundation for Post-doctorate of China （Grant No 2004035083）.

摘　　要：Based on the energy transfer process from host to dopant in an organic electrophosphorescent （EP） device, the expression of energy transfer probability （η） between the host （TPD） and guest （Ir（ppy）3） EP systems was proposed. The results show that： （1） The rate of the triplet energy transfer （KHG and KGH） increases exponentially with increasing donor-acceptor molecular distance （R）, whereas decreases as the intermolecular distance （RHH） increases from 0.8 to 2.4 nm. Furthermore, KGH changes more quickly than KHG. （2） The energy transfer probability （η） increases as R reduces, and the RHH changes can be safely neglected for R〈0.9 nm. The situation changes for 0.9nm〈 R 〈 1.1nm, RHH （〈1nm） plays an essential role when η changes and increases with the latter. However, if R〉1.1nm, the transfer probability will be below zero. Here, the energy transfer principle may be less important, and the high electroluminescence （EL） quantum efficiency of phosphorescent system will be attributed to the direct electron-hole recombination in phosphorescent molecules. （3） The η will increase when the Forster radius （R0） increases or Gibb＇s energy decreases.Based on the energy transfer process from host to dopant in an organic electrophosphorescent （EP） device, the expression of energy transfer probability （η） between the host （TPD） and guest （Ir（ppy）3） EP systems was proposed. The results show that： （1） The rate of the triplet energy transfer （KHG and KGH） increases exponentially with increasing donor-acceptor molecular distance （R）, whereas decreases as the intermolecular distance （RHH） increases from 0.8 to 2.4 nm. Furthermore, KGH changes more quickly than KHG. （2） The energy transfer probability （η） increases as R reduces, and the RHH changes can be safely neglected for R〈0.9 nm. The situation changes for 0.9nm〈 R 〈 1.1nm, RHH （〈1nm） plays an essential role when η changes and increases with the latter. However, if R〉1.1nm, the transfer probability will be below zero. Here, the energy transfer principle may be less important, and the high electroluminescence （EL） quantum efficiency of phosphorescent system will be attributed to the direct electron-hole recombination in phosphorescent molecules. （3） The η will increase when the Forster radius （R0） increases or Gibb＇s energy decreases.

关 键 词：ELECTROPHOSPHORESCENCE energy transfer TRIPLET 

分 类 号：O562[理学—原子与分子物理]