Solution-processable, star-shaped bipolar tetraphenylethene derivatives for the fabrication of efficient nondoped OLEDs

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Materials for optical and electronic devices, 2016-01, Vol.4 (14), p.2775-2783
• Main Authors: Chen, Long, Zhang, Chongyang, Lin, Gengwei, Nie, Han, Luo, Wenwen, Zhuang, Zeyan, Ding, Siyang, Hu, Rongrong, Su, Shi-Jian, Huang, Fei, Qin, Anjun, Zhao, Zujin, Tang, Ben Zhong
• Format: Article
• Language: English
• Subjects: Derivatives; Electroluminescence; Emission; Emitters; Luminance; Organic light emitting diodes; Polymers; Variability
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/c5tc02949j

Organic light-emitting diodes (OLEDs) based on solution-processable small molecules are attracting intense attention, as such technology combines the merits of low-cost solution processability of polymers and finely defined structural uniformity of small molecules. Small-molecule tetraphenylethene (TPE) derivatives are excellent solid-state light emitters featuring aggregation-induced emission (AIE) characteristics, however those that can be used in solution-processable devices are very rare. To address this issue, herein, a series of novel star-shaped bipolar TPE derivatives are synthesized and characterized. Their thermal stabilities, photophysical properties, electronic structures, electrochemical behaviors, and application in solution-processed OLEDs are investigated systematically. These luminogens exhibit AIE characteristics and excellent fluorescence quantum yields up to 95% in the solid state. Nondoped OLEDs are successfully fabricated through a spin-coating method. The solution-processed OLEDs [ITO (130 nm)/PEDOT:PSS (40 nm)/emitter (70 nm)/TPBi (30 nm)/Ba (4 nm)/Al (120 nm)] adopting star-shaped TPE derivatives as light-emitting layers show peak luminance of 11 665 cd m −2 and high electroluminescence (EL) efficiencies up to 8.3 cd A −1 , 2.6% and 7.5 lm W −1 . These results demonstrate a promising avenue towards efficient nondoped OLEDs based on solution-processable AIE-active small molecules. Star-shaped tetraphenylethene derivatives containing electron-donor and acceptor groups are synthesized and utilized in solution-processed nondoped OLEDs.