Thermally activated delayed fluorescence enantiomers for solution-processed circularly polarized electroluminescence

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Materials for optical and electronic devices, 2019, Vol.7 (46), p.14511-14516
• Main Authors: Sun, Sibing, Wang, Jun, Chen, Lingfeng, Chen, Runfeng, Jin, Jibiao, Chen, Cailin, Chen, Shufen, Xie, Guohua, Zheng, Chao, Huang, Wei
• Format: Article
• Language: English
• Subjects: Carbazoles; Circular polarization; Diodes; Donors (electronic); Electroluminescence; Enantiomers; Fluorescence; Organic light emitting diodes; Photoluminescence
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/c9tc04941j

Circularly polarized organic light-emitting diodes (CP-OLEDs) with thermally activated delayed fluorescence (TADF) characteristics are receiving increasing interest, as they have shown improving efficiencies of circularly polarized electroluminescence (CPEL). Here, we developed a series of TADF enantiomers based on chiral binaphthalene, an acceptor (A) of cyanopyridine, and donors (D) of carbazoles in a chiral-A-D architecture. Good solubility, high luminescence yields, and excellent chiral stability with a photoluminescence dissymmetry factor ( g PL ) up to 5.8 × 10 −4 were achieved. Efficient CP-OLEDs using these chiral TADF molecules as dopants were successfully fabricated, exhibiting high external quantum efficiencies (EQEs) up to 12.4% and opposite CPEL signals with g EL of 6 × 10 −4 /−8.6 × 10 −4 in vacuum-deposited devices. More impressively, the solution-processed TADF CP-OLEDs result in much larger g EL values (3.5 × 10 −3 /−3.9 × 10 −3 ) with EQEs up to 10.6%. This discovery is encouraging and instructive, which could stimulate the development of high-performance CP-OLEDs using chiral TADF molecules through solution-processing approaches. Enantiomers with circularly polarized (CP) thermally activated delayed fluorescence were designed in a chiral-D-A architecture for solution-processed high-efficiency CP-OLEDs.