Yang Yiyu, Li Nengquan, Miao Jingsheng, Cao Xiaosong, Ying Ao, Pan Ke, Lv Xialei, Ni Fan, Huang Zhongyan, Gong Shaolong, Yang Chuluo
Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, P. R. China.
Department of Chemistry, Renmin Hospital of Wuhan University, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Wuhan University, Wuhan, 430072, China.
Angew Chem Int Ed Engl. 2022 Jul 25;61(30):e202202227. doi: 10.1002/anie.202202227. Epub 2022 Jun 8.
Highly efficient circularly polarized luminescence (CPL) emitters with narrowband emission remain a formidable challenge for circularly polarized OLEDs (CP-OLEDs). Here, a promising strategy for developing chiral emitters concurrently featuring multi-resonance thermally activated delayed fluorescence (MR-TADF) and circularly polarized electroluminescence (CPEL) is demonstrated by the integration of molecular rigidity, central chirality and MR effect. A pair of chiral green emitters denoted as (R)-BN-MeIAc and (S)-BN-MeIAc is designed. Benefited by the rigid and quasi-planar MR-framework, the enantiomers not only display mirror-image CPL spectra, but also exhibit TADF properties with a high photoluminescence quantum yield of 96 %, a narrow FWHM of 30 nm, and a high horizontal dipole orientation of 90 % in the doped film. Consequently, the enantiomer-based CP-OLEDs achieved excellent external quantum efficiencies of 37.2 % with very low efficiency roll-off, representing the highest device efficiency of all the reported CP-OLEDs.
对于圆偏振有机发光二极管（CP - OLED）而言，拥有窄带发射的高效圆偏振发光（CPL）发射器仍然是一项艰巨的挑战。在此，通过整合分子刚性、中心手性和多共振热激活延迟荧光（MR - TADF）效应，展示了一种开发同时具有多共振热激活延迟荧光和圆偏振电致发光（CPEL）的手性发射器的有效策略。设计了一对手性绿色发射器，记为（R）- BN - MeIAc和（S）- BN - MeIAc。受益于刚性和准平面的MR框架，这些对映体不仅显示出镜像CPL光谱，而且在掺杂薄膜中还表现出TADF特性，具有96%的高光致发光量子产率、30 nm的窄半高宽以及90%的高横向偶极取向。因此，基于对映体的CP - OLED实现了37.2%的优异外量子效率，且效率滚降非常低，代表了所有已报道的CP - OLED中的最高器件效率。
