High‐Efficiency Near‐Infrared Fluorescent Organic Light‐Emitting Diodes with Small Efficiency Roll‐Off: A Combined Design from Emitters to Devices
High‐Efficiency Near‐Infrared Fluorescent Organic Light‐Emitting Diodes with Small Efficiency Roll‐Off: A Combined Design from Emitters to Devices
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DOI：
10.1002/adfm.201703283
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发表时间：
2017-12
影响因子：
19
通讯作者：
J. Xue;Q. Liang;Yunge Zhang;Ruoyun Zhang;Lian Duan;J. Qiao
中科院分区：
文献类型：
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作者：
J. Xue;Q. Liang;Yunge Zhang;Ruoyun Zhang;Lian Duan;J. Qiao
同时实现高量子产率和激子利用效率（ηr）仍然是近红外（NIR）荧光有机发光二极管（FOLED）中的一个艰巨挑战。为了实现高量子产率，我们设计并合成了一种新型近红外染料 4,9-双(4-(二苯氨基)苯基)-萘并[2,3-c][1,2,5]硒二唑，具有较大的最高占据分子轨道/最低未占据分子轨道重叠和聚集诱导发射特性，其在甲苯中 743 nm 处的光致发光量子产率为 27%，在甲苯中的光致发光量子产率为 29%。混合膜中的 723 nm。对于高 ηr，选择橙色发射热激活延迟荧光材料 1,2-双（9,9-二甲基-9,10-二氢吖啶）-4,5-二氰基苯作为在器件中收获三线态激子的敏化主体。优化后的器件在 730 nm 处实现了 45.7% 的良好 ηr 和高达 2.65% 的高外部量子效率，在 200 mA cm−2 处效率滚降非常小，为 2.41%，这是 700 nm 以上 NIR-FOLED 的最有效值之一。通过热激活延迟荧光敏化主体有效利用三线态激子将为实现效率滚降较小的高效 NIR-FOLED 铺平道路。
The simultaneous realization of high quantum yield and exciton utilizing efficiency (ηr) 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 ηr, 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 ηr 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.