Emitters with narrowband spectra are of great importance nowadays because of the growing demand for ultra-high-definition displays in the fields of panel displays and solid-state lighting. Though the reported multiple resonance (MR) emitters have been widely studied with extremely sharp spectra and color-tunable emissions, the electrophilic borylation synthetic strategies and stable narrowband blue devices still face great challenges. Herein, by virtue of the advantages of both the MR effect of conventional indolocarbazole skeleton and the easy-to-access of B—N covalent bonds, the linear tert-butyl benzene and carbazole groups modified 6,12-diphenyl-5,11-dihydroindolo[3,2-b]carbazole derivatives (tPh[BN] and Cz[BN]) containing two B—N covalent bonds are easily constructed through amine-directed double borylation strategy. Both emitters behaved bright blue emission with full-width-at-half-maximum (FWHM) of 20—27 nm in solution, high fluorescence quantum efficiency over 90%, and excellent stability toward moisture. By employing triplet-triplet annihilation electroluminescent mechanism, blue OLED devices based on them showed a small FWHM of 48 nm and maximum external quantum efficiency of ~7.1% with negligible efficiency roll-off, and long operational lifetime (LT80) of 87 h at an initial brightness of 1000 cd·m⁻², demonstrating the enormous application potential of B—N bonds embedded emitters in achieving ideal narrowband blue emitters.

中文翻译：

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基于 B—N 键嵌入 6,12-二苯基-5,11-二氢吲哚并 [3,2-b] 咔唑的高效稳定蓝色 OLED，具有窄带发射和长寿命†

由于平板显示和固态照明领域对超高清显示器的需求不断增长，窄带光谱发射器在当今非常重要。尽管已报道的多共振 (MR) 发射器已被广泛研究，具有极其尖锐的光谱和颜色可调的发射，但亲电硼化合成策略和稳定的窄带蓝色器件仍然面临巨大挑战。在此，利用传统吲哚并咔唑骨架的MR效应和B—N共价键易接近的优点，线性叔丁基苯和咔唑基团修饰的6,12-二苯基-5,11-二氢吲哚[3,2- b]咔唑衍生物（tPh[BN] 和 Cz[BN]）含有两个 B—N 共价键，很容易通过胺导向的双硼化策略构建。两种发射体均表现出明亮的蓝色发射，在溶液中半峰全宽 (FWHM) 为 20-27 nm，荧光量子效率超过 90%，并且对水分具有出色的稳定性。通过采用三重态-三重态湮灭电致发光机制，基于它们的蓝色 OLED 器件显示出 48 nm 的小 FWHM 和约 7.1% 的最大外量子效率，效率滚降可忽略不计，并且在 87 小时的长工作寿命 (LT80) 1000 cd·m ^-2的初始亮度，展示了B—N键嵌入式发射器在实现理想的窄带蓝色发射器方面的巨大应用潜力。