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Near-infrared polymer light-emitting diodes based on an inverted device structure
摘要： Near-infrared polymer light-emitting diodes (NIR-PLEDs) possess great potential in applications ranging from night-vision device to optical communications. Here we obtained NIR emission from normal red fluorescent polymers by using an inverted device structure with the aid of micro-cavity effects. By tuning the thickness of the emissive layer, the inverted NIR-PLED based on PPF-FSO15-DHTBT10 and MEH-PPV got a near-infrared emission with the main peak located at 700 nm and 706 nm, and the maximum external quantum efficiency (EQEmax) of 0.54% and 1.03%, respectively. The increase of emissive layer thickness caused the relative variation of recombination area, which led to the widely controlling of EL spectra in the inverted device. These results reveal that tuning EL spectrum utilized by inverted device structure would be a promising method to realize near-infrared emission.
关键词： emissive layer thickness,micro-cavity effects,inverted device structure,Near-infrared polymer light-emitting diodes,external quantum efficiency
更新于2025-09-11 14:15:04
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Deep-blue light-emitting polyfluorenes with asymmetrical naphthylthio-fluorene as Chromophores
摘要： A novel blue polycyclic aromatic compound 2,8-dibromo-14,14-dioctyl-14H-benzo[b]benzo [5,6] fluoreno[1,2-d] thiophene 9,9-dioxide (Br2NFSO) is designed and synthesized through multistep synthesis, and its structure is confirmed by nuclear magnetic resonance. Based on synthesized polycyclic aromatic compound Br2NFSO, a series of twisted blue light-emitting polyfluorenes derivatives (PNFSOs) are prepared by one-pot Suzuki polycondensation. Based on the twisted polymer molecular structure resulted from the asymmetric links of 14,14-dioctyl-14H-benzo[b]benzo[5,6]fluoreno [1,2-d]thiophene 9,9-dioxide (NFSO) unit in copolymers and better electron transport ability of NFSO than those of the electron-deficient dibenzothiophene-S,S-dioxide counterpart, the resulting polymers exhibit excellent electroluminescent spectra stability in the current densities from 100 to 800 mA cm?2, and show blue-shifted and narrowed electroluminescent spectra with the Commission Internationale de L0Eclairage (CIE) of (0.16, 0.07) for PNFSO5, compared to poly(9,9-dioctylfluorene) (PFO) with the CIE of (0.18, 0.18). Moreover, the superior device performance is achieved based on PNFSO5 with the maximum luminous efficiency (LEmax) of 1.96 cd A?1, compared with the LEmax of 0.49 cd A?1 for PFO. The results indicate that the twisted polycyclic aromatic structure design strategy has a great potential to tuning blue emission spectrum and improving EL efficiency of blue light-emitting polyfluorenes.
关键词： twisted structure,polycyclic aromatic compound,polymer light-emitting diodes,intromolecular charge transfer,synthesis
更新于2025-09-09 09:28:46
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Novel blue light emitting poly(arylene ether)s under the influence of guest concentrations in host-guest systems: Synthesis, electrochemical and photophysical properties
摘要： A series of novel blue (poly-arylene ether)s polymers based on the anthracene derivatives as the guest material, and the hole transfer carbazole dervatives as the host material have been successfully synthesized by nucleophilic polycondensation. The obtained polymers exhibited high glass transition temperatures (Tg) ranging from 180 to 255 °C and decomposition temperatures (Td) ranging from 358 to 477 °C. Number average molecular weight (Mn) ranged from 3.12 × 104 to 7.20 × 104, and polydispersity indices (PDI) ranged from 1.25 to 2.10. Cyclic voltammetry investigation inform that these polymers possess LUMO energy levels ranging from ?2.29 to ?2.46 eV. In case of thin films state, all the polymers emit blue luminance with the emission maximum peaks ranging from 442 to 448 nm. The electroluminescent devices based on the these polymers with a configuration of ITO/PEDOT:PSS/polymer/TmPyPB/LiF/Al emitted blue light with CIE chromaticity coordinates of (0.15, 0.10).
关键词： Polymer Light Emitting Diodes,Ether Linkage,Blue Light Emission,Anthracene,Carbazole
更新于2025-09-04 15:30:14