Open Access
Stabilized Blue Emission from Polyfluorene-Based Light-Emitting Diodes: Elimination of Fluorenone Defects
Xiong Gong
- Vol. 13
TLDR
In this paper, the photoluminescence (PL) and electroluminescent (EL) of polyfluorene (PF)-based light-emitting diodes (LEDs) were studied and it was shown that the low-energy emission band originates from fluorenone defects which are introduced by photo-oxidization, thermal oxidation, or during device fabrication.Abstract:
Polyfluorene (PF)-based light-emitting diodes (LEDs) typically exhibit device degradation under operation with the emergence of a strong low-energy emission band (at ∼ 2.2–2.4 eV). This longer wavelength band converts the desired blue emission to blue–green or even yellow. We have studied both the photoluminescence (PL) and electroluminescence (EL) of PFs with different molecular structures and found that the low-energy emission band originates from fluorenone defects which are introduced by photo-oxidization, thermal oxidation, or during device fabrication. X-ray photo-emission spectroscopy (XPS) results show that the oxidation of PF is strongly catalyzed by the presence of calcium. The fluorenone defects generate a stronger contribution to the EL than to the PL. By utilization of a novel electron-transporting material as a buffer layer between the emissive PF and the Ca/Ag (Ba/Ag) cathode, the blue EL emission from the PF was stabilized.read more
Citations
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Functionalization of emissive conjugated polymer nanoparticles by coprecipitation: consequences for particle photophysics and colloidal properties.
Amita Singh,Michael Bezuidenhout,Nichola Walsh,Jason Beirne,Riccardo Felletti,Suxiao Wang,Kathleen T. Fitzgerald,William M. Gallagher,Patrick A. Kiely,Gareth Redmond +9 more
TL;DR: The functionalization of polyfluorene nanoparticles by coprecipitation of the conjugated polymer with an amphiphilic comb polymer, consisting of a hydrophobic polystyrene backbone with hydrophilic, carboxylic acid-terminated polyethylene oxide side-chains, is investigated.
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Visualization of trap dilution in polyfluorene based light-emitting diodes
TL;DR: In this article, the effect of electron trapping and trap-assisted recombination on light-emitting diodes (PLEDs) was shown to be strongly suppressed by diluting a semiconducting polymer with a large band gap polymer such as polystyrene.
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Design, synthesis, photophysical, and electrochemical properties of DCM‐based conjugated polymers for light‐emitting devices
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Exploring the experimental photoluminescence, Raman and infrared responses and density functional theory results for TFB polymer
Wesley Renzi,Neusmar J. A. Cordeiro,Henrique de Santana,Marcello Ferreira da Costa,Marco A. T. da Silva,Edson Laureto,José Leonil Duarte +6 more
TL;DR: In this paper, the structural and optical properties of the copolymer poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4′-( N -(4-sec-butylphenyl)diphenylamine)] (TFB) are investigated.
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Development of CaO supported on modified geopolymer catalyst for transesterification of soybean oil to biodiesel
Natkanin Supamathanon,Kornkanok Boonserm,Sireerat Lisnund,Narong Chanlek,Bunyarat Rungtaweevoranit,Pongtanawat Khemthong,Jatuporn Wittayakun,Nattawut Osakoo +7 more
TL;DR: Heterogeneous base catalysts, CaO supported on modified geopolymer (Geo), were developed and characterized as low-cost catalyst for biodiesel production from the transesterification of soybean oil.
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