磷光
有机发光二极管
材料科学
偶极子
各向异性
光电子学
准分子
光致发光
分子物理学
光学
物理
荧光
纳米技术
量子力学
图层(电子)
作者
Miaosheng Wang,Dian Luo,Tzu‐Hung Yeh,Yi‐Hsuan Huang,Chang‐Lun Ko,Wen‐Yi Hung,Yipeng Tang,Shun‐Wei Liu,Ken‐Tsung Wong,Bin Hu
标识
DOI:10.1002/adom.202202477
摘要
Abstract Designing in‐plane‐oriented light‐emitting dipoles is known as a critical method to develop high‐efficiency organic light‐emitting diodes (OLEDs) by enhancing light extraction. However, in‐plane‐oriented light‐emitting dipoles must demonstrate sufficient polarization memory extended into light emission lifetime window, generating extended anisotropy dynamics shown as the necessary condition to increase light extraction toward developing high‐efficiency OLEDs. This paper reports experimental studies on anisotropy dynamics of light‐emitting dipoles in both time and energy domains by using time‐resolved and steady‐state photoluminescence anisotropy measurements based on the in‐plane oriented exciplex‐heterostructured [BCzPh:CN‐T2T] host dispersed with phosphorescent molecules. It is found that, when host–guest Coulomb scattering is suppressed by parallel placing of the in‐plane‐configured phosphorescent Ir(ppy) 2 (acac) molecules into the in‐plane‐oriented exciplex‐heterostructured [BCzPh:CN‐T2T] host, the anisotropy dynamics of light‐emitting dipoles can be extended into microseconds time window comparable with its phosphorescence lifetime, satisfying the necessary condition in time domain to increase light out‐coupling efficiency toward developing high external quantum efficiencies (EQEs) in Ir(ppy) 2 (acac):exciplex system. More importantly, by suppressing host–guest Coulomb scattering, the high‐energy transition dipoles can still maintain extended anisotropy dynamics in the energy domain in Ir(ppy) 2 (acac):exciplex system while hot electrons are relaxing toward lowest unoccupied molecular orbital (LUMO). Consequently, the extended anisotropy dynamics of light‐emitting dipoles demonstrate a high EQE of 34.01% in the Ir(ppy) 2 (acac):exciplex OLED.
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