系统间交叉
有机发光二极管
分子内力
磷光
光化学
材料科学
量子效率
辐射传输
兴奋剂
发光
氢键
荧光
分子
化学
光电子学
纳米技术
原子物理学
单重态
立体化学
光学
有机化学
物理
图层(电子)
激发态
作者
Taehyun Kim,Sunyoung Sohn,Sungjin Park,Wanuk Choi,Hyungju Ahn,Sungjune Jung,Taiho Park
标识
DOI:10.1016/j.cej.2023.147444
摘要
Organic multifunctional triplet-harvesting emitters based organic light emitting diodes (OLEDs) are a relatively unexplored area, primarily due to the challenging requirements of achieving high rates of intersystem crossing (ISC; kISC > 107 s−1), reverse intersystem crossing (RISC; kRISC > 106 s−1), radiative decay (kr > 107 s−1), and low non-radiative decay (knr < 106 s−1) within non-doped systems. In this study, we synthesized three asymmetric heavy-atom-free (HAF) multifunctional triplet-harvesting emitters. The incorporation of intramolecular hydrogen bonding (IHB) induced conformational locking and distortion, resulting in a quasi-planar structure that effectively reduces reorganization energy (λ). Consequently, Qx-Py-2DMAC exhibited improved radiative characteristics with high quantum yields (0.94) in neat film state. Significantly, the existence of IHB interactions was confirmed through various methods, including DFT calculations, single-crystal XRD, and 2D-GIWAXD measurements, which verified the effect in both single molecules and solid states. Subsequently, the IHB-induced conformation-locked structure exhibited a preferred orientation with a large coherence length (Lc) for dense packing and efficient emission in aggregated state. Consequently, due to the IHB-induced unique aggregation properties, Qx-Py-2DMAC realized significant multifunctionality of aggregation-induced emission (AIE), mechanochromic luminescence (MCL), thermally activated delayed fluorescence (TADF), and room-temperature phosphorescence (RTP) in solid state. In this regard, non-doped OLEDs were successfully realized.
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