Triplet exciton confinement and unconfinement by adjacent hole-transport layers
Triplet exciton confinement and unconfinement by adjacent hole-transport layers
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DOI：
10.1063/1.1751232
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发表时间：
2004-06-15
影响因子：
3.2
通讯作者：
Adachi, C
中科院分区：
文献类型：
--
作者：
Goushi, K;Kwong, R;Adachi, C
为了理解空穴传输层对Ir（ppy）（3）的三重态激子的限制，我们比较了掺杂到4，4 '-双[N-（2-甲基苯基）-2-氧代-1，2，4-三唑-1-基]吡啶中的Ir（ppy）（3）的三重态激子的能量耗散过程。（1-萘基）-N-苯基-氨基]联苯（α-NPD）、4，4 '-双[N-（对甲苯基）-N-苯基-氨基]联苯（TPD）、1，1-双[（二-4-甲苯基氨基）苯基]环己烷（TAPC）和4，4'-N，N '-二咔唑-联苯主体。观察到从Ir（ppy）（3）到α-NPD的三重态能级的显著能量转移。然而，在TPD主体的情况下，观察到Ir（ppy）（3）三重态激子的部分限制。该结果表明从Ir（ppy）（3）到TPD三重态能级的前向和后向能量转移。此外，采用TAPC作为空穴传输层实现了对Ir（ppy）（3）三重态激子的强限制。从这些结果得出的一个结论是，电致磷光效率与空穴传输层主体材料的三重态能级很好地相关。(C)2004年，美国物理学会。
To understand confinement of the triplet exciton of Ir(ppy)(3) by hole-transport layers, we compared energy-dissipative processes of the triplet exciton of Ir(ppy)(3) which is doped into 4,4'-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl (alpha-NPD), 4,4'-bis [N-(p-tolyl)-N- phenyl-amino]biphenyl (TPD), 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC), and 4,4'-N,N'-dicarbazole-biphenyl hosts. Significant energy transfer from Ir(ppy)(3) into the triplet levels of alpha-NPD was observed. In the case of the TPD host, however, partial confinement of the Ir(ppy)(3) triplet exciton was observed. This result suggests both forward and backward energy transfer from Ir(ppy)(3) to the TPD triplet levels. Furthermore, employing TAPC as a hole-transport layer achieved strong confinement of the Ir(ppy)(3) triplet exciton. One conclusion from these results is that electrophosphorescence efficiency is well correlated with the triplet energy level of the hole-transport layer host materials. (C) 2004 American Institute of Physics.