近日，深圳大学杨楚罗&曹啸松及其研究团队取得一项新进展。经过不懈努力，他们利用多共振发射体的B-N共价键参与π扩展策略，成功实现高性能窄带电致发光。相关研究成果已于2024年3月23日在国际知名学术期刊《国家科学评论》上发表。

该研究团队提出了BN共价键参与π-扩展策略，通过MR框架的后功能化，成功构建了高阶的B/N基基序。这种结构上的和电子上的π-体系扩展不仅提升了分子的刚性，从而有效缩小了发射线宽，还促进了系统间的反向交叉，进而减轻了效率滚降的问题。如案例所示，研究人员已成功开发出超窄带天蓝发射器，其在正己烷中的半宽仅为8 nm。与前驱体发射器相比，该发射器的光物理性质得到了全方位的提升。

这一突破使得窄带OLED的外部量子效率高达42.6%，同时显著减少了在高亮度下的效率下降，代表了单主机OLED的最佳效率。这些发射器的成功研发，不仅彰显了该研究团队先进MR-TADF发射器分子设计策略的有效性，也充分证明了这些发射器在高性能光电器件领域中的巨大潜力。

据悉，多硼嵌入的多共振热激活延迟荧光（MR-TADF）发射器，在理论上有望实现高色纯度发射和高激子利用效率，具有广阔的应用前景。然而，在实际发展过程中，这些发射器常常受到合成范围有限以及分子量过高的限制，这不仅增加了材料获取的难度，也给真空沉积有机发光二极管（OLED）的制造带来了不小的挑战。

附：英文原文

Title: B-N covalent bond-involved π-extension of multiple resonance emitters enables high-performance narrowband electroluminescence

Author: Huang, Xingyu, Liu, Jiahui, Xu, Yulin, Chen, Guohao, Huang, Manli, Yu, Mingxin, Lv, Xialei, Yin, Xiaojun, Zou, Yang, Miao, Jingsheng, Cao, Xiaosong, Yang, Chuluo

Issue&Volume: 2024-03-23

Abstract: Multi-boron-embedded multiple resonance thermally activated delayed fluorescence (MR-TADF) emitters show promise for achieving both high color-purity emission and high exciton utilization efficiency. However, their development is often impeded by a limited synthetic scope and excessive molecular weights, which challenge material acquisition and organic light-emitting diode (OLED) fabrication by vacuum deposition. Herein, we put forward a BN covalent bond-involved π-extension strategy via post-functionalization of MR frameworks, leading to the generation of high-order B/N-based motifs. The structurally and electronically extended π-system not only enhances molecular rigidity to narrow emission linewidth but also promotes reverse intersystem crossing to mitigate efficiency roll-off. As illustrated examples, ultra-narrowband sky-blue emitters (full-width at half-maximum as small as 8 nm in n-hexane) have been developed with multi-dimensional improvement in photophysical properties compared to their precursor emitters, which enables narrowband OLEDs with external quantum efficiencies (EQEmax) of up to 42.6%, in company with alleviated efficiency decline at high brightness, representing the best efficiency reported for single-host OLEDs. The success of these emitters highlights the effectiveness of our molecular design strategy for advanced MR-TADF emitters and confirms their extensive potential in high-performance optoelectronic devices.

DOI: 10.1093/nsr/nwae115

Source: https://academic.oup.com/nsr/advance-article/doi/10.1093/nsr/nwae115/7634363?login=true