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- Xiong, Wenjing, 1989, et al.
(author)
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Combining Benzotriazole and Benzodithiophene Host Units in Host-Guest Polymers for Efficient and Stable Near-Infrared Emission from Light-Emitting Electrochemical Cells
- 2019
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In: Advanced Optical Materials. - : Wiley. - 2195-1071 .- 2162-7568. ; 7:15
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Journal article (peer-reviewed)abstract
- A set of host-guest copolymers with alternating benzodithiophene and benzotriazole (BTz) derivatives as host units and 4,7-bis(5-bromothiophen-2-yl)-benzo[c][1,2,5]thiadiazole as the minority guest are synthesized, characterized, and evaluated for applications. A light-emitting electrochemical cell (LEC) comprising such a host-guest copolymer delivers fast-response near-infrared (NIR) emission peaked at 723 nm with a high radiance of 169 mu W cm(-2) at a low drive voltage of 3.6 V. The NIR-LEC also features good stability, as the peak NIR output only drops by 8% after 350 h of continuous operation. It is, however, found that the LEC performance is highly sensitive to the detailed chemical structure of the host backbone, and that the addition of electron-donating thiophene bridging units onto the BTz unit is highly positive while the inclusion of fluorine atoms results in a drastically lowered performance, presumably because of the emergence of hydrogen bonding within the active material.
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