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
More filters
Journal ArticleDOI
Multilayer polymer light-emitting diodes : White-light emission with high efficiency
Journal ArticleDOI
Star-shaped π-conjugated oligomers and their applications in organic electronics and photonics
TL;DR: These structures are monodisperse, well-defined, discrete molecules with 100% synthetic reproducibility, and possess high purity and excellent solubility in common organic solvents and are therefore extremely attractive alternatives to conjugated polymers.
Journal ArticleDOI
Suzuki Polycondensation: Polyarylenes à la Carte
TL;DR: This review draws a rather comprehensive picture of how Suzuki polycondensation was discovered in 1989 and how it was subsequently developed into the most powerful polymerization method for polyarylenes during the last 20 years.
Journal ArticleDOI
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.
Journal ArticleDOI
Efficient blue-emitting silafluorene–fluorene-conjugated copolymers: selective turn-off/turn-on detection of explosives
TL;DR: In this article, the synthesis and spectroscopic characterization of a series of new blue-emitting silafluorene-fluorene copolymers is described, which are synthesized using kinetically controlled hydrosilylation copolymerization of 1,1-dihydridosilafluoresne with a series 9-substituted 2,7-diethynylfluorenes.
References
More filters
Dissertation
Electroabsorption investigations of advanced polymer light-emitting diodes
TL;DR: In this paper, the authors employ electroabsorption spectroscopy in the study of encapsulated blue polymer light-emitting diodes (PLEDs), introduced generally in Chapter 1, that also incorporate a hole injection layer poly(3,4-ethylene dioxythio- phene) doped with poly(styrene sulfonate) (PEDOT:PSS).
Journal ArticleDOI
Enhanced Green Electrophosphorescence from Oxadiazole-Functionalized Iridium Complex-Doped Devices Using Poly(9,9-Dioctylfluorene) Instead of Poly(N-Vinylcarbazole) as a Host Matrix
TL;DR: In this paper, the oxadiazole-functionalized iridium complex-doped polymer light-emitting devices (PLEDs) are demonstrated with two different polymeric host matrices at the dopant concentrations 1-8%.
Journal ArticleDOI
The role of segregation in the polarized emission from polyfluorene embedded in a liquid crystal
Lavinia Ghirardini,Tersilla Virgili,Serena Bolis,Serena Bolis,Jeroen Beeckman,Pascal Kockaert,Marco Finazzi,Michele Celebrano +7 more
TL;DR: In this paper, a nematic liquid crystal (LC) matrix with polyfluorene (PFO) embedded in a viscous liquid crystal matrix is investigated and it is found that most of the light emission originates from these boundaries and gets strongly pinned along their orientation.
Journal ArticleDOI
Polymer Nanoparticles Microenvironment: Using Photophysical Probes to Investigate Internal Porosity and Polarity
TL;DR: The objective of this work was to probe the internal morphology, porosity, and polarity of conjugated polymer poly[9,9-di(2-ethylhexyl)-fluorenyl-2,7-diyl] (PF2/6) nanoparticles (NPs) to assess their feasibility as drug-delivery vehicles.
Journal ArticleDOI
Polymer Light‐emitting Diodes Based on End‐capped Poly[9,9‐di‐(2′‐ethylhexyl)fluorenyl‐2,7‐diyl]
TL;DR: In this article, the authors demonstrate polymer light-emitting diodes (LEDs) based on poly[9,9-di-(2′-ethylhexyl)fluorenyl-2,7-diyl] with end capper dimethylphenyl or N,N-bis(4-methylphenyl)-N-phenylamine.