Xue Zhuixing, Hu Yuxuan, Xiao Shengbing, Liu Jiahui, Miao Jingsheng, 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.
Angew Chem Int Ed Engl. 2025 Apr 7;64(15):e202500108. doi: 10.1002/anie.202500108. Epub 2025 Feb 5.
The development of pure-green organic emitters with ideal emission peaks and ultra-narrow full-widths at half-maximum (FWHMs) remains a formidable challenge. Herein, we report two new green emitters, CNBN and MCNBN, which achieve extremely narrow FWHMs by synergistic rigid π-extension and cyano-substitution of a sky-blue multi-resonance thermally activated delayed fluorescence (MR-TADF) core. The introduction of cyano groups induces red-shifts in the emission to the green region and dramatically minimizes the FWHMs. In toluene solution, CNBN and MCNBN exhibit narrowband emission with a maximum at 501 nm and 510 nm with ultra-narrow FWHMs of 14 nm/0.066 eV and 15 nm/0.071 eV, respectively. Given the near-unity photoluminescence quantum yields and almost 100 % horizontal dipole orientation, the electroluminescent (EL) devices based on CNBN and MCNBN deliver external quantum efficiencies (EQEs) exceeding 30 % with FWHMs of 16 nm/0.072 eV and 17 nm/0.080 eV, respectively. Notably, the MCNBN-based device achieves pure-green emission with a maximum at 517 nm with Commission Internationale de l'Éclairage coordinates of (0.17, 0.74), closely aligning with the BT.2020 green standard.
开发具有理想发射峰和超窄半高宽（FWHM）的纯绿色有机发光体仍然是一项艰巨的挑战。在此，我们报道了两种新型绿色发光体CNBN和MCNBN，它们通过天蓝色多共振热激活延迟荧光（MR-TADF）核的协同刚性π-扩展和氰基取代实现了极窄的FWHM。氰基的引入导致发射峰红移至绿色区域，并显著减小了FWHM。在甲苯溶液中，CNBN和MCNBN表现出窄带发射，最大发射波长分别为501 nm和510 nm，超窄FWHM分别为14 nm/0.066 eV和15 nm/0.071 eV。鉴于近乎统一的光致发光量子产率和几乎100%的水平偶极取向，基于CNBN和MCNBN的电致发光（EL）器件的外量子效率（EQE）分别超过30%，FWHM分别为16 nm/0.072 eV和17 nm/0.080 eV。值得注意的是，基于MCNBN的器件实现了纯绿色发射，最大发射波长为517 nm，国际照明委员会坐标为（0.17, 0.74），与BT.2020绿色标准紧密匹配。
