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Highly Efficient Near‐Infrared Organic Light‐Emitting Diode Based on a Butterfly‐Shaped Donor–Acceptor Chromophore with Strong Solid‐State Fluorescence and a Large Proportion of Radiative Excitons
Author(s) -
Yao Liang,
Zhang Shitong,
Wang Rong,
Li Weijun,
Shen Fangzhong,
Yang Bing,
Ma Yuguang
Publication year - 2014
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201308486
Subject(s) - oled , chromophore , exciton , quantum efficiency , fluorescence , optoelectronics , acceptor , excited state , materials science , radiative transfer , photochemistry , near infrared spectroscopy , diode , chemistry , optics , atomic physics , nanotechnology , physics , layer (electronics) , quantum mechanics , condensed matter physics
The development of near‐infrared (NIR) organic light‐emitting diodes (OLEDs) is of growing interest. Donor–acceptor (D–A) chromophores have served as an important class of NIR materials for NIR OLED applications. However, the external quantum efficiencies (EQEs) of NIR OLEDs based on conventional D–A chromophores are typically below 1 %. Reported herein is a butterfly‐shaped D–A compound, PTZ‐BZP. A PTZ‐BZP film displayed strong NIR fluorescence with an emission peak at 700 nm, and the corresponding quantum efficiency reached 16 %. Remarkably, the EQE of the NIR OLED based on PTZ‐BZP was 1.54 %, and a low efficiency roll‐off was observed, as well as a high radiative exciton ratio of 48 %, which breaks through the limit of 25 % in conventional fluorescent OLEDs. Experimental and theoretical investigations were carried out to understand the excited‐state properties of PTZ‐BZP.