Highly efficient deep-blue light-emitting copolymers containing phenoxazine: enhanced device efficiency and lifetime by blending a hole transport molecule
| Autor: | Ting Guo, Shengzu Liao, Feng Peng, Lei Ying, Zhenqiang Huang, Yong Cao, Jiajian He, Zhiqi Huang, Zhiming Zhong |
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| Rok vydání: | 2019 |
| Předmět: |
Photoluminescence
Materials science Analytical chemistry Quantum yield 02 engineering and technology General Chemistry Electroluminescence 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Electrochemical energy conversion 0104 chemical sciences Full width at half maximum Materials Chemistry Thermal stability Quantum efficiency 0210 nano-technology Luminous efficacy |
| Zdroj: | Journal of Materials Chemistry C. 7:13859-13866 |
| ISSN: | 2050-7534 2050-7526 |
| DOI: | 10.1039/c9tc04721b |
| Popis: | A series of deep-blue light-emitting copolymers with an emission peak at 455 nm and narrow full width at half-maximum (FWHM) of about 40 nm were synthesized by incorporating a small amount of 10-(4-hexylphenyl)-10H-phenoxazine (PO) unit into the backbone of poly(9,9-dioctylfluorene). All the copolymers exhibit good thermal stability, high photoluminescent quantum yield and appropriate electrochemical energy levels. The copolymer PF-TD2PO1 which contains 1 mol% PO unit shows a maximum luminous efficiency (LEmax) of 3.07 cd A−1 and 5.18 cd A−1 based on single-layer and double-layer devices, respectively, with deep-blue Commission Internationale de L’E’clairage (CIE) coordinates of (0.15, 0.11). To improve the hole transport of the emissive layer, a hole transport molecule N-([1,1′-biphenyl]-4-yl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazo-yl)-phenyl)-9H-fluorene-2-amine (BCFN) was blended into PF-TD2PO1. As a result, the best electroluminescence performance with a low turn-on voltage of 3.0 V, a superior LEmax of 6.20 cd A−1 (corresponding to a maximum external quantum efficiency of 6.22%), an unprecedented luminance of 44 685 cd m−2 and deep-blue CIE coordinates of (0.15, 0.11) were obtained from the blended PF-TD2PO1:BCFN light emitting device. It is particularly important that PF-TD2PO1:BCFN based devices exhibit very slow efficiency roll-off and a more than 14 times enhanced lifetime compared with the devices without BCFN. The results indicate the great potential of this class of copolymers for application in solution processed deep-blue light-emitting diodes with high efficiency and long lifetime. |
| Databáze: | OpenAIRE |
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