Multi-resonance (MR) emitters based on boron-nitrogen doped polycyclic aromatic hydrocarbons are the cutting-edge light-emitting materials for organic light-emitting diodes (OLEDs) due to their high photoluminescence quantum yield and narrowband emission spectra. Among all the widely-reported MR molecules, emitters showing pure-red emission are the least developed. The difficulty in designing pure-red MR emitters lies in the limit of the weak charge transfer nature of the MR framework, as well as the large molecular weight which may bring difficulty in vacuum sublimation process. Herein, through introducing the strong electron donating phenoxazine and phenothiazine moiety into the double-boron-based MR molecular skeleton, two novel MR emitters namely PXZBNO and PTZBNO were designed and synthesized. These two emitters exhibited pure-red emission with emission maxima up to 627 nm, small full-width at half-maximum (FWHM) of 45 nm. Red OLEDs based on PTZBNO demonstrated very high maximum external quantum efficiency (EQE_max) of 34.5%, together with very small efficiency roll-off. Meanwhile, PXZBNO-based purity pure-red OLEDs exhibited high color purity with color coordinates of (0.69, 0.31), which is approaching BT. 2020 standard.

基于硼氮掺杂多环芳烃的多共振（MR）发射器由于其高光致发光量子产率和窄带发射光谱而成为有机发光二极管（OLED）的尖端发光材料。在所有广泛报道的MR分子中，显示纯红色发射的发射体是最不发达的。设计纯红色MR发射体的困难在于MR骨架的弱电荷转移性质的限制，以及大分子量可能给真空升华过程带来困难。在此，通过将强给电子吩恶嗪和吩噻嗪部分引入双硼基MR分子骨架中，两种新型MR发射体PXZBNO和PTZBNO被设计和合成。这两个发射器表现出纯红色发射，发射最大值高达 627 nm，半峰全宽 (FWHM) 为 45 nm。基于PTZBNO的红色 OLED表现出非常高的最大外量子效率 (EQE _max)，高达 34.5%，并且效率滚降非常小。同时，基于PXZBNO的纯红色OLED表现出高色纯度，色坐标为(0.69，0.31)，接近BT。2020年标准。