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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Blue-light-emitting oligoquinolines: Synthesis, properties, and high-efficiency blue-light-emitting diodes
Christopher J. Tonzola,Abhishek P. Kulkarni,Angela P. Gifford,Werner Kaminsky,Samson A. Jenekhe +4 more
TL;DR: In this article, the synthesis, photophysics, cyclic voltammetry, and highly efficient blue electroluminescence of a series of n-type conjugated oligomers are reported.
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Efficient blue-emitting silafluorene–fluorene-conjugated copolymers: selective turn-off/turn-on detection of explosives
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References
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Electronic Characterization of New Bright-Blue-Light-Emitting Poly(9,9-dioctylfluorenyl-2,7-diyl)-End Capped With Polyhedral Oligomeric Silsesquioxanes
TL;DR: In this paper, the spectral and cyclic voltammetry measurements of the new blue-light-emitting polymer poly(9,9-dioctylfluorenyl-2,7-diyl) end capped with polyhedral oligomeric silsesquioxanes (POSS) were performed.
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One-dimensional micro-scale patterned conjugated polymer structures in bilayer architecture and light emitting diode application
TL;DR: In this paper, the authors pattern aligned micrometer scale conjugated polymer structures using a solution-based processing method to maximize luminescent brightness in organic light-emitting diode (OLED) systems.
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Low energy emission bands in a small molecular fluorene derivative for organic light-emitting diodes
TL;DR: In this article, the low energy emission bands from 530 to 570 nm were observed from the electroluminescence (EL) and photoluminecence (PL) spectra of BFLBBFLYQ films in ultrahigh vacuum circumstance, and the origin of these emission features were investigated and discussed.
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Sodium hydroxide/aluminum bilayer cathode for enhancing the performance of blue polymer light-emitting diodes
TL;DR: Sodium hydroxide/aluminum bilayer cathode has been developed for improving the performance of blue polymer light-emitting diodes (PLEDs) based on poly(9,9-dioctylfluorene) as mentioned in this paper.
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Novel fluorene/trifluoromethylphenylene copolymers: Synthesis, spectra stability and electroluminescence
TL;DR: The trifluoromethylphenylene unit was introduced into the copolymer backbone and its content ratio was varied from 10 −mol% to 50 −mol%. In contrast to pure polyfluorene, the deep-blue fluorescence of these copolymers is quite stable and not contaminated by the well-known green emission associated with fluorenone defects.