Narrowing the Electroluminescence Spectra of Multiresonance Emitters for High-Performance Blue OLEDs by a Peripheral Decoration Strategy
Narrowing the Electroluminescence Spectra of Multiresonance Emitters for High-Performance Blue OLEDs by a Peripheral Decoration Strategy
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通过外围装饰策略缩小高性能蓝色 OLED 多谐振发射器的电致发光光谱
DOI：
10.1021/acsami.1c18704
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Yang C
中科院分区：
文献类型：
--
作者：
Qiu Y;Xia H;Miao J;Huang Z;Li N;Cao X;Han J;Zhou C;Zhong C;Yang C
开发具有高效率和窄带发射的有机热激活延迟荧光（TADF）发射体对于高质量有机发光二极管（OLED）来说是至关重要和具有挑战性的。在此，三种多共振TADF发射体DPACzBN 1、DPACzBN 2和DPACzBN 3通过外围装饰策略设计，并通过锂中间级联硼化反应（DPACzBN 1的产率为15%）或更有效的无锂直接硼化反应（DPACzBN 2的产率为45%，DPACzBN 3的产率为75%）合成。所有的发射体都表现出类似的蓝色发射，在甲苯溶液中具有低至20 nm的小的半峰全宽（fwhm）值。在母体分子DPACzBN 1中引入二苯氨基基团不仅可以保持90%以上的高光致发光量子产率，而且可以使带宽变窄，提高反向系间穿越过程的速率常数，并抑制器件中的光谱展宽。基于DPACzBN 3的TADF OLED具有优良的TADF特性和良好的光谱展宽抑制性能，在三种发光体中，最大外量子效率最高，为27.7%，半高宽最小，为24 nm。
Developing organic thermally activated delayed fluorescence (TADF) emitters with high efficiency and narrowband emissions is crucial and challenging for high-quality organic light-emitting diodes (OLEDs). Here, three multiresonance TADF emitters DPACzBN1, DPACzBN2, and DPACzBN3 are designed via a peripheral decoration strategy and synthesized through a lithium intermediate cascade borylation reaction (15% yield for DPACzBN1) or a more efficient lithium-free direct borylation reaction (45% yield for DPACzBN2 and 75% yield for DPACzBN3). All the emitters exhibit a similar blue emission with small full-width at half maximum (fwhm) values as low as 20 nm in toluene solutions. The introduction of the diphenylamino moiety into the parent molecule DPACzBN1 can not only maintain the high photoluminescence quantum yields over 90% but also narrow the bandwidth and enhance the rate constant of the reverse intersystem crossing process, as well as suppress the spectral broadening in devices. Benefiting from the excellent TADF properties and good inhibition of spectral broadening, TADF OLEDs based on DPACzBN3 achieve the highest maximum external quantum efficiency of 27.7% and the smallest fwhm of 24 nm among the three emitters.