Optical and Electronic Properties of Doubly Ortho-linked cis-4,4'-Bis(diarylamino)stilbene/Fluorene Hybrids

2010 ◽  
Vol 63 (1) ◽  
pp. 125 ◽  
Author(s):  
Yan-Ling Liu ◽  
Xue-Qin Ran ◽  
Ji-Kang Feng ◽  
Ai-Min Ren ◽  
Lu-Yi Zou
Keyword(s):  
High Efficiency ◽  
Blue Emission ◽  
Emission Spectra ◽  
Functional Materials ◽  
Hole Transport ◽  
Light Emitting ◽  
Optical And Electronic Properties ◽  
Experimental Values ◽  
The Relationship ◽  
Highest Occupied Molecular Orbitals

Doubly ortho-linked cis-4,4′-bis(diarylamino)stilbene/fluorene hybrids have potential application in organic light emitting diodes. These organic molecules can function as efficient hole transport materials, with sky-blue emission and high efficiency and stability. To reveal the relationship between the properties and structures of these functional materials, we apply quantum-chemical techniques to investigate their optical properties and electronic structures. It is found that 8- and 8′-substituents give an antibonding contribution to the highest occupied molecular orbitals (HOMO), thus increasing the HOMO energy, implying an enhancement of hole-creating ability. Changes in ionization potentials confirm this presumption. The absorption and emission spectra exhibit red shifts to some extent with the various 8- and 8′-substituents, which are in good agreement with the experimental values. The Stoke shifts range moderately from 40 to 86 nm, due to the rigid spiral structure that hinders geometrical relaxation.

scholarly journals Synthesis and Photoluminescence Properties of New Conjugated Oligoquinolines 2, 2’-Bis (4-phenylquinoline) 1, 4 Phenylene

2021 ◽  
pp. 243-249
Author(s):  
L. K. Bedre ◽  
B. M. Bahirwar
Keyword(s):  
Organic Compounds ◽  
High Efficiency ◽  
Condensation Reaction ◽  
Blue Emission ◽  
Emission Spectra ◽  
Photoluminescence Properties ◽  
Light Emitting ◽  
N2 Atmosphere ◽  
Organic Phosphor ◽  
Device Applications

A novel 2,2’-Bis(4-Phenylquinoline )1,4 phenylene(BPQ-P) organic phosphor was synthesized in Aragon(Ar) and Nitrogen (N2) atmosphere at 140oC by using Friedlander Condensation reaction. Based on our previously synthesized DPQ, we systemically designed some novel derivatives with tuned optical properties & the compound showed blue emission under a UV source. The synthesized organic phosphor is assessed by various characterization techniques such as FTIR and NMR spectroscopy. Using excitation and emission spectra were analysed the properties of PL in organic compounds. The synthesized organic phosphors show bright emission in the blue region, with the peaks at 483nm for 4-phenylquinoline. The physical and photoluminescence properties of these organic compounds reveal promising blue emitters for high efficiency organic light emitting diodes (OLEDS) and it may also find device applications as n-type semiconductors.

scholarly journals Solution-Processed Efficient Blue Phosphorescent Organic Light-Emitting Diodes (PHOLEDs) Enabled by Hole-Transport Material Incorporated Single Emission Layer

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 554
Author(s):  
Taeshik Earmme
Keyword(s):  
Light Emitting Diodes ◽  
Blue Emission ◽  
Hole Transport ◽  
Organic Light Emitting Diodes ◽  
Emission Layer ◽  
Solution Processed ◽  
Light Emitting ◽  
Organic Light ◽  
Single Emission ◽  
Blue Phosphorescent

Solution-processed blue phosphorescent organic light-emitting diodes (PHOLEDs) based on a single emission layer with small-molecule hole-transport materials (HTMs) are demonstrated. Various HTMs have been readily incorporated by solution-processing to enhance hole-transport properties of the polymer-based emission layer. Poly(N-vinylcarbazole) (PVK)-based blue emission layer with iridium(III) bis(4,6-(di-fluorophenyl)pyridinato-N,C2′)picolinate (FIrpic) triplet emitter blended with solution-processed 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) gave luminous efficiency of 21.1 cd/A at a brightness of 6220 cd/m2 with an external quantum efficiency (EQE) of 10.6%. Blue PHOLEDs with solution-incorporated HTMs turned out to be 50% more efficient compared to the reference device without HTMs. The high hole mobility, high triplet energy of HTM, and favorable energy transfer between HTM blended PVK host and FIrpic blue dopant were found to be important factors for achieving high device performance. The results are instructive to design and/or select proper hole-transport materials in solution-processed single emission layer.

Efficient deep-blue non-doped organic light-emitting diode with improved roll-off of efficiency based on hybrid local and charge-transfer excited state

RSC Advances ◽  
2016 ◽  
Vol 6 (74) ◽  
pp. 70085-70090 ◽  
Author(s):  
Haichao Liu ◽  
Qing Bai ◽  
Weijun Li ◽  
Yachen Guo ◽  
Liang Yao ◽  
...  
Keyword(s):  
Excited State ◽  
High Efficiency ◽  
Light Emitting Diode ◽  
Blue Emission ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Deep Blue ◽  
Organic Light ◽  
Slow Roll ◽  
Donor Acceptor

Acceptor–donor–acceptor triphenylamine–phenanthroimidazole derivate (TPA–2PPI) servers as an emitter, whose device exhibits deep-blue emission, high efficiency and slow roll-off of efficiency.

scholarly journals Alternative p-doped hole transport material for low operating voltage and high efficiency organic light-emitting diodes

2014 ◽  
Vol 105 (11) ◽  
pp. 113303 ◽  
Author(s):  
Caroline Murawski ◽  
Cornelius Fuchs ◽  
Simone Hofmann ◽  
Karl Leo ◽  
Malte C. Gather
Keyword(s):  
High Efficiency ◽  
Light Emitting Diodes ◽  
Hole Transport ◽  
Organic Light Emitting Diodes ◽  
Operating Voltage ◽  
Light Emitting ◽  
Organic Light

Design of pyridinylphosphinate-based blue iridium phosphors for high-efficiency organic light-emitting diodes

2021 ◽  
Author(s):  
Zheng-Guang Wu ◽  
Bing Yang ◽  
Yu-Chen Qiu ◽  
Yang Wang ◽  
Hong Dai ◽  
...  
Keyword(s):  
Electron Mobility ◽  
High Efficiency ◽  
Light Emitting Diodes ◽  
Blue Emission ◽  
Organic Light Emitting Diodes ◽  
Iridium Complexes ◽  
Light Emitting ◽  
Organic Light ◽  
Novel Design

Novel design for iridium complexes merging blue emission and good electron mobility for high-efficiency OLEDs.

Organic Syntheses and Characteristics of Novel Conjugated Polymers for AMOLEDs

2010 ◽  
Vol 75 ◽  
pp. 91-96
Author(s):  
Su Hee Song ◽  
Young Eup Jin ◽  
Joo Young Shim ◽  
Kwang Hee Lee ◽  
Hong Suk Suh
Keyword(s):  
Conjugated Polymers ◽  
Blue Emission ◽  
Wavelength Region ◽  
Emission Spectra ◽  
Polymer Backbone ◽  
Light Emitting ◽  
Long Wavelength ◽  
New Class ◽  
Solid Thin Films ◽  
Pl Emission

Conjugated polymers with a stabilized blue emission are of importance for the realization of large flat panel AMOLED displays using polymer light-emitting diodes. Several novel conjugated polymers using newly developed templates for the stabilized EL emission are reported. Poly(2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[def]phenanthrene)) (PCPP) is a new class of blue-emitting polymers utilizing a new back-bone. This material emits a efficient blue EL without exhibiting any unwanted peak in the long wavelength region (green region) even after prolonged annealing at an elevated temperature of 150oC in air, or operation of the device. New electroluminescent spiro-PCPPs, poly((2,6-(3',6'-bis(2-ethylhexyloxy)-spiro(4H-cyclopenta[def] phenanthrene-4,9'-[9H]fluorene)))-alt-(2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[def]phenanthrene))) (spiro-PCPP-alt-PCPP) and poly((2,6-(3',6'-bis(2-ethylhexyloxy)-spiro(4H-cyclopenta[def] phenanthrene-4,9'-[9H]fluorene)))-alt-(1,4-phenylene)) (spiro-PCPPP), have been synthesized by the Suzuki polymerization. The PL emission spectra of polymers in THF solution show a same maximum peak at 397 nm. The maximum PL emission spectra of polymers appeared at around 463 and 456 nm in solid state, respectively. The PL spectra in solid thin films show more red-shifted over 60 nm than solution conditions. The blue emissions at 400-409 nm for the π–π* transitions of conjugated polymer backbone are almost completely quenched or decreased.

Graphene Oxide Inserted Poly(N -Vinylcarbazole)/Vanadium Oxide Hole Transport Heterojunctions for High-Efficiency Quantum-Dot Light-Emitting Diodes

2017 ◽  
Vol 4 (15) ◽  
pp. 1700476 ◽  
Author(s):  
Young Ran Park ◽  
Kyoung Soon Choi ◽  
Jong Chan Kim ◽  
Young Soo Seo ◽  
Soo Young Kim ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Quantum Dot ◽  
Vanadium Oxide ◽  
High Efficiency ◽  
Light Emitting Diodes ◽  
Hole Transport ◽  
Light Emitting

High-efficiency new polymer light-emitting diodes with a stabilized blue emission

2005 ◽  
Author(s):  
Sung Heum Park ◽  
Jin Young Kim ◽  
Sun Hee Kim ◽  
Youngeup Jin ◽  
Jinwoo Kim ◽  
...  
Keyword(s):  
High Efficiency ◽  
Light Emitting Diodes ◽  
Blue Emission ◽  
Light Emitting ◽  
Polymer Light Emitting Diodes

Color Tunability of Blue Phosphors by Changing Cations for Near-UV InGaN-Based Light-Emitting Diode

2014 ◽  
Vol 986-987 ◽  
pp. 156-159
Author(s):  
Yi Wen Zhu ◽  
Fen Fen Hu ◽  
Mei Li Zhou ◽  
Ping Chen ◽  
Zheng Liang Wang
Keyword(s):  
Uv Light ◽  
Light Emitting Diode ◽  
Blue Emission ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Blue Shift ◽  
Ionic Radii ◽  
Light Emitting ◽  
Triclinic Structure ◽  
The Difference

The serials of blue phosphors, CaAl2Si2O8: Eu2+ doped with different content Sr2+ and Mg2+ ions, were prepared by solid-state reaction at high temperature. And their structure and photo-luminescent properties were investigated. In Ca0.96-ySryAl2Si2O8: 0.04Eu2+ (y = 0.10, 0.30, 0.50, 0.70, 0.90) system, for y ≦ 0.03, all the compositions crystallize in triclinic structure of CaAl2Si2O8, and on further increase of y, the system undergoes a compositionally induced phase transition from triclinic to monoclinic structure. For Ca0.96-yMgyAl2Si2O8: 0.04Eu2+ (y = 0.10, 0.30, 0.50, 0.70, 0.90) system, for z ≦ 0.03, all the compositions are of triclinic structure of CaAl2Si2O8. With the further increase of z, other phase appears. The emission spectra of these phosphors show blue shift with the introduction of Sr2+ ions, and red shift with Mg2+ ions. The reason may be due to the difference ionic radii of Mg2+, Ca2+, Sr2+. These phosphors show excellent blue emission and broad excitation band in near-UV (ultraviolet) range. They may be potential phosphors for near-UV light-emitting diodes (LEDs).

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