Oda Susumu, Kawakami Bungo, Horiuchi Masaru, Yamasaki Yuki, Kawasumi Ryosuke, Hatakeyama Takuji
Department of Chemistry, Graduate School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo, 669-1337, Japan.
Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.
Adv Sci (Weinh). 2022 Nov 17;10(1):e2205070. doi: 10.1002/advs.202205070.
Ultra-narrowband blue multi-resonance-induced thermally activated delayed fluorescence (MR-TADF) materials (V-DABNA and V-DABNA-F), consisting of three DABNA subunits possessing phenyl or 2,6-difluorophenyl substituents on the peripheral nitrogen atoms are synthesized by one-shot triple borylation. Benefiting from the inductive effect of fluorine atoms, the emission maximum of V-DABNA-F (464 nm) is blueshifted from that of the parent V-DABNA (481 nm), while maintaining a small full width at half maximum (FWHM, 16 nm) and a high rate constant for reverse intersystem crossing (6.5 × 10 s ). The organic light-emitting diodes (OLEDs) using V-DABNA and V-DABNA-F as emitters are fabricated by vapor deposition and exhibit blue emission at 483 and 468 nm with small FWHMs of 17 and 15 nm, corresponding to Commission Internationale d'Éclairage coordinates of (0.09, 0.27) and (0.12, 0.10), respectively. Both devices achieve high external quantum efficiencies of 26.2% and 26.6% at the maximum with minimum efficiency roll-offs of 0.9% and 3.2%, respectively, even at 1000 cd m , which are record-setting values for blue MR-TADF OLEDs.
通过单次三硼化反应合成了由三个在外围氮原子上带有苯基或2,6 - 二氟苯基取代基的DABNA亚基组成的超窄带蓝色多共振诱导热激活延迟荧光（MR - TADF）材料（V - DABNA和V - DABNA - F）。得益于氟原子的诱导效应，V - DABNA - F的最大发射波长（464 nm）相对于母体V - DABNA（481 nm）发生蓝移，同时保持较小的半高宽（FWHM，16 nm）和较高的反向系间窜越速率常数（6.5×10 s）。以V - DABNA和V - DABNA - F作为发光体的有机发光二极管（OLED）通过气相沉积制备，在483和468 nm处呈现蓝色发射，半高宽分别为17和15 nm，对应的国际照明委员会坐标分别为（0.09, 0.27）和（0.12, 0.10）。即使在1000 cd m时，这两种器件的最大外量子效率分别达到26.2%和26.6%，最小效率滚降分别为0.9%和3.2%，这是蓝色MR - TADF OLED的创纪录值。
