有机发光二极管
超快激光光谱学
材料科学
光电子学
荧光
激发态
化学机械平面化
共振(粒子物理)
放松(心理学)
窄带
超短脉冲
单重态
光谱学
化学
原子物理学
纳米技术
激光器
光学
物理
社会心理学
量子力学
心理学
图层(电子)
作者
Yixuan Gao,Yaxin Wang,Zilong Guo,Yan Wan,Chenglong Li,Bing Yang,Wensheng Yang,Xiaonan Ma
标识
DOI:10.1021/acs.jpcb.2c00144
摘要
Multiple-resonance thermally activated delayed fluorescence (MR-TADF) emitters are becoming increasingly attractive due to their applications in high-resolution organic light-emitting diode (OLED) display technology. Here, we present an investigation on the photophysics of two MR-TADF emitters (t-DABNA and TBN-TPA) by using quantum chamical calculation and ultrafast transient absorption (TA) spectroscopy. Compared with one-step structural planarization of t-DABNA, TBN-TPA undergoes two-step relaxation in S1 state, i.e., fast twisting of the peripheral group and subsequent restrained planarization of the B-N framework. The efficient twisting motion of the peripheral group largely reduces the energy level of the TBN-TPA system and correspondingly increases the barrier for subsequent planarization, which is favored for the narrowband emission. Our work provides a detailed picture for the excited-state deactivation of peripheral group-modified MR-TADF emitters without a pronounced charge-transfer (CT) characteristic mixed in the lowest-lying fluorescent state, which might be helpful for the future design of narrowband OLED emitters.
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