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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Journal ArticleDOI
Controlling Optoelectronic Behavior in Poly(fluorene) Networks Using Thiol–Ene Photo-Click Chemistry
TL;DR: In this article, the effects of network architecture on cross-linked conjugated poly(fluorene) thin-film networks were investigated using FTIR, contact profilometry, and photo calorimetry.
Journal ArticleDOI
Polyfluorene presenting dipolar pendent groups and its application to electroluminescent devices
TL;DR: In this article, a blue-light-emitting polyfluorene derivative (PF-TPAOXD) was synthesized, which presents sterically hindered, dipolar pendent groups functionalized at the C-9 positions of alternating fluorene units.
Journal ArticleDOI
Synthesis and optoelectronic properties of silole‐containing polyfluorenes with binary structures
TL;DR: In this article, a modified one-pot synthesis with a reverse addition procedure was used to synthesize 2,5-Bis(2-bromofluorene-7-yl) silole by a modified 1-pot one-step synthesis, from which novel silole-containing polyfluorenes with binary random and alternating structures (silole contents between 4.5 and 25% and high Mw up to 509 kDa were successfully synthesized.
Journal ArticleDOI
π‐Conjugated Dendrimers as Stable Pure‐Blue Emissive Materials: Photophysical, Electrochemical, and Electroluminescent Properties
TL;DR: The investigation of their photophysical properties indicates that G0 and G1 are promising blue-light emitting materials with good stability, and such strategy provides a platform to achieve pure-blue emitting dendrimer-like materials with high efficiency for use as OLEDs.
Journal ArticleDOI
The built-in potential in blue polyfluorene-based light-emitting diodes
Vladimir Bodrozic,Vladimir Bodrozic,Thomas M. Brown,Shabbir M. Mian,Daren J. Caruana,Daren J. Caruana,Matthew Roberts,Nathan Phillips,Jonathan Halls,Ilaria Grizzi,Jeremy Burroughes,Franco Cacialli,Franco Cacialli +12 more
TL;DR: In this paper, energy level alignment in polyfluorene-based polymer light-emitting diodes (PLEDs) is studied with electroabsorption spectroscopy and cyclic voltammetry (CV).
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