Naphthothiadiazole-Based Near-Infrared Emitter with a Photoluminescence Quantum Yield of 60% in Neat Film and External Quantum Efficiencies of up to 3.9% in Nondoped OLEDs
Naphthothiadiazole-Based Near-Infrared Emitter with a Photoluminescence Quantum Yield of 60% in Neat Film and External Quantum Efficiencies of up to 3.9% in Nondoped OLEDs
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萘并噻二唑基%20近红外%20发射器%20with%20a%20光致发光%20Quantum%20产率%20of%2060%%20in%20Neat%20Film%20and%20外部%20Quantum%20效率%20of%20up%20to%203.9%%20in%
DOI：
10.1002/adfm.201606384
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发表时间：
2017-03-24
影响因子：
19
通讯作者：
Yang, Chuluo
中科院分区：
文献类型：
--
作者：
Liu, Tengxiao;Zhu, Liping;Yang, Chuluo
由于器件效率的突破和新的发光机理，荧光发光材料在有机发光二极管（OLED）领域重新受到关注。这为开发新型近红外荧光发射体和高效器件提供了良好的机遇。本文设计合成了一种以萘并噻二唑为受体的D-p-A-p-D型化合物4，4 '-（萘并[2，3-c][1，2，5]噻二唑-4，9-二基）双（N，N-二苯基苯胺）（NZ 2 TPA）。电子物理研究和密度泛函理论分析表明，该化合物的发光具有明显的杂化局域态和电荷转移态（HLCT）特征。此外，该化合物显示聚集诱导发射（AIE）特性。由于其HLCT机制和AIE特性，NZ 2 TPA在纯膜中获得了前所未有的高达60%的光致发光量子产率，这是已报道的有机小分子近红外发光体中最高的，甚至超过了大多数磷光近红外材料。基于NZ 2 TPA的非掺杂器件表现出优异的性能，其最大外量子效率（EQE）为3.9%，发射峰位于696 nm，亮度为6330 cd m（-2），在已报道的非掺杂近红外荧光OLED中是最高的。此外，该器件在1000 cd m（-2）的高亮度下保持2.8%的高EQE，具有非常低的效率滚降。
Fluorescent emitters have regained intensive attention in organic light emitting diode (OLED) community owing to the breakthrough of the device efficiency and/or new emitting mechanism. This provides a good chance to develop new near-infrared (NIR) fluorescent emitter and high-efficiency device. In this work, a D-p-A-p-D type compound with naphthothiadiazole as acceptor, namely, 4,4'-(naphtho[2,3-c][1,2,5] thiadiazole-4,9-diyl) bis(N,N-diphenylaniline) (NZ2TPA), is designed and synthesized. The photophysical study and density functional theory analysis reveal that the emission of the compound has obvious hybridized local and charge-transfer (HLCT) state feature. In addition, the compound shows aggregation-induced emission (AIE) characteristic. Attributed to its HLCT mechanism and AIE characteristic, NZ2TPA acquires an unprecedentedly high photoluminescent quantum yield of 60% in the neat film, which is the highest among the reported organic small-molecule NIR emitters and even exceeds most phosphorescent NIR materials. The nondoped devices based on NZ2TPA exhibit excellent performance, achieving a maximum external quantum efficiency (EQE) of 3.9% with the emission peak at 696 nm and a high luminance of 6330 cd m(-2), which are among the highest in the reported nondoped NIR fluorescent OLEDs. Moreover, the device remains a high EQE of 2.8% at high brightness of 1000 cd m(-2), with very low efficiency roll-off.