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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High‐efficiency blue light‐emitting polymers based on 3,6‐silafluorene and 2,7‐silafluorene
TL;DR: In this article, a blue-emitting polymer based on 3,6-silafluorene and 2,7-silafluororene was synthesized via Suzuki polycondensation.
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Hydrogen Bonds and Enhanced Aggregation Emission of Organic and Polymeric Fluorophores with Alternative Fluorene and Naphthol Units
TL;DR: In this article, the influence of the hydrogen bonds (H-bonds) on the emission behavior of fluorescent organic compound (FN) and polymer PFN with alternative fluorene and naphthol units was assessed.
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Synthesis and characterization of new carbazole/fluorene‐based derivatives for blue‐light‐emitting devices
TL;DR: In this paper, 2,7-Bis(9-ethylcarbazol-3-yl)-9,9-di(2-ethylhexyl)fluorene and a segmented copolymer composed of the same chromophores alternated with hexamethylene fragments were synthesized.
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Stabilized blue emission from polyfluorene-based light-emitting diodes: The role of triphenylamine
TL;DR: In this article, a deep study of the optical properties related to the performances in light-emitting diodes (LEDs) of a fluorene-based copolymer containing triphenylamine (TPA), showed a huge reduction of oxidation of the whole material, a macromolecule separation, hence preventing the crystalline aggregation, an improved time-stability of both material chromaticity and morphology compared with commercial poly(9,9-dioctylfluorene) (PFO).
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The first observation of electroluminescence from di(2-naphthyl)disilene, an SiSi double bond-containing π-conjugated compound
TL;DR: Air-stable, room-temperature emissive di(2-naphthyl)disilene can emit light in an organic light-emitting diode, thus providing the first experimental demonstration of electroluminescence from the heavy group 14 unsaturated compounds.
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