Rational Design of Aggregation-Induced Emission Luminogen with Weak Electron Donor鈥揂cceptor Interaction to Achieve Highly Efficient Undoped Bilayer OLEDs

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• 作者：Long Chen ; Yibin Jiang ; Han Nie ; Rongrong Hu ; Hoi Sing Kwok ; Fei Huang ; Anjun Qin ; Zujin Zhao ; Ben Zhong Tang
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2014
• 出版时间：October 8, 2014
• 年：2014
• 卷：6
• 期：19
• 页码：17215-17225
• 全文大小：521K
• ISSN：1944-8252

文摘

In this work, two tailored luminogens (TPE-NB and TPE-PNPB) consisting of tetraphenylethene (TPE), diphenylamino, and dimesitylboryl as a 蟺-conjugated linkage, electron donor, and electron acceptor, respectively, are synthesized and characterized. Their thermal stabilities, photophysical properties, solvachromism, fluorescence decays, electronic structures, electrochemical behaviors, and electroluminescence (EL) properties are investigated systematically, and the impacts of electron donor鈥揳cceptor (D鈥揂) interaction on optoelectronic properties are discussed. Due to the presence of a TPE unit, both luminogens show aggregation-induced emission, but strong D鈥揂 interaction causes a decrease in emission efficiency and red-shifts in photoluminescence and EL emissions. The luminogen, TPE-PNPB, with a weak D鈥揂 interaction fluoresces strongly in solid film with a high fluorescence quantum yield of 94%. The trilayer OLED [ITO/NPB (60 nm)/TPE-PNPB (20 nm)/TPBi (40 nm)/LiF (1 nm)/Al (100 nm)] utilizing TPE-PNPB as a light emitter shows a peak luminance of 49鈥?93 cd m^鈥? and high EL efficiencies up to 15.7 cd A^鈥?, 12.9 lm W^鈥?, and 5.12%. The bilayer OLED [ITO/TPE-PNPB (80 nm)/TPBi (40 nm)/LiF (1 nm)/Al (100 nm)] adopting TPE-PNPB as a light emitter and hole transporter simultaneously affords even better EL efficiencies of 16.2 cd A^鈥?, 14.4 lm W^鈥?, and 5.35% in ambient air, revealing that TPE-PNPB is an eximious p-type light emitter.

Keywords:

aggregation-induced emission; tetraphenylethene; electron donor鈭抋cceptor; hole transporter; organic light-emitting diodes