量子效率
量子产额
材料科学
荧光
有机发光二极管
轨道能级差
激子
光电子学
光致发光
红外线的
甲苯
发光效率
能量转换效率
二极管
光化学
纳米技术
光学
图层(电子)
物理
作者
Jie Xue,Qingxin Liang,Yunge Zhang,Ruoyun Zhang,Lian Duan,Juan Qiao
标识
DOI:10.1002/adfm.201703283
摘要
Abstract The simultaneous realization of high quantum yield and exciton utilizing efficiency (η r ) is still a formidable challenge in near‐infrared (NIR) fluorescent organic light‐emitting diodes (FOLEDs). Here, to achieve a high quantum yield, a novel NIR dye, 4,9‐bis(4‐(diphenylamino)phenyl)‐naphtho[2,3‐ c ][1,2,5]selenadiazole, is designed and synthesized with a large highest occupied molecular orbital/lowest unoccupied molecular orbital overlap and an aggregation‐induced emission property, which demonstrates a high photoluminescence quantum yield of 27% at 743 nm in toluene and 29% at 723 nm in a blend film. For a high η r , an orange‐emitting thermally activated delayed fluorescent material, 1,2‐bis(9,9‐dimethyl‐9,10‐dihydroacridine)‐4,5‐dicyanobenzene, is chosen as the sensitizing host to harvest triplet excitons in devices. The optimized devices achieve a good η r of 45.7% and a high external quantum efficiency up to 2.65% at 730 nm, with a very small efficiency roll‐off of 2.41% at 200 mA cm −2 , which are among the most efficient values for NIR‐FOLEDs over 700 nm. The effective utilization of triplet excitons via the thermally activated delayed fluorescence‐sensitizing host will pave a way to realize high‐efficiency NIR‐FOLEDs with small efficiency roll‐off.
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