Murto, P;
Minotto, A;
Zampetti, A;
Xu, X;
Andersson, MR;
Cacialli, F;
Wang, E;
(2016)
Triazolobenzothiadiazole-Based Copolymers for Polymer Light-Emitting Diodes: Pure Near-Infrared Emission via Optimized Energy and Charge Transfer.
Advanced Optical Materials
, 4
(12)
pp. 2068-2076.
10.1002/adom.201600483.
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Abstract
A series of new near-infrared (NIR) emitting copolymers, based on a low band gap 6-(2-butyloctyl)-4,8-di(thiophen-2-yl)-[1,2,3]triazolo[4′,5′:4,5]benzo[1,2-c]-[1,2,5]thiadiazole (TBTTT) fluorophore copolymerized into a high band gap poly[3,3′-ditetradecyl-2,2′-bithiophene-5,5′-diyl-alt-5-(2-ethylhexyl)-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione-1,3-diyl] (P2TTPD) host backbone, for polymer light-emitting diode (PLED) applications is reported. PLEDs fabricated from the host polymer (P2TTPD-0) show external quantum efficiencies (EQEs) up to 0.49% at 690 nm, with turn-on voltage (Von) at only 2.4 V. By incorporating the TBTTT segments into the host polymer backbone, pure NIR emission peaking at ca. 900 nm is obtained with Von remaining below 5 V. This work demonstrates that such a low Von can be attributed to efficient intrachain energy and/or charge transfer to the TBTTT sites. When the NIR emitting copolymer (P2TTPD-10) is blended with P2TTPD-0, the TBTTT are confined to well-separated polymer chains. As a result, the EQE from the blend is lower and the Von higher than that obtained from the pure copolymer (P2TTPD-1.0) with equal content of TBTTT. An analogous copolymer (P4T-1.0), consisting of poly[3,3′-ditetradecyl-2,2′:5′,2′′:5′′,2′′′-quaterthiophene-5,5′′′-diyl] (P4T) as the host and 1% TBTTT as the NIR emitter, further demonstrates that pure NIR emission can be obtained only through optimized molecular orbital energy levels, as in P2TTPD-1.0, which minimizes chances for either charge trapping or exciton splitting.
| Type: | Article |
|---|---|
| Title: | Triazolobenzothiadiazole-Based Copolymers for Polymer Light-Emitting Diodes: Pure Near-Infrared Emission via Optimized Energy and Charge Transfer |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1002/adom.201600483 |
| Publisher version: | http://dx.doi.org/10.1002/adom.201600483 |
| Language: | English |
| Additional information: | This is the peer reviewed version of the following article: Murto, P., Minotto, A., Zampetti, A., Xu, X., Andersson, M. R., Cacialli, F. and Wang, E. (2016), Triazolobenzothiadiazole-Based Copolymers for Polymer Light-Emitting Diodes: Pure Near-Infrared Emission via Optimized Energy and Charge Transfer. Advanced Optical Materials, 4: 2068–2076., which has been published in final form at http://dx.doi.org/10.1002/adom.201600483. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. |
| Keywords: | Science & Technology, Technology, Physical Sciences, Materials Science, Multidisciplinary, Optics, Materials Science, Heterojunction Solar-Cells, Conjugated Polymers, High-Efficiency, Excited-States, Gap Polymer, Deep Red, Fluorescence, Transport, Electroluminescence, Devices |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/1519050 |
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