Novel hole transport materials based on N,N′-disubstituted-dihydrophenazine derivatives for electroluminescent diodes

2014 ◽  
Vol 2 (46) ◽  
pp. 9858-9865 ◽  
Author(s):  
Zhiwen Zheng ◽  
Qingchen Dong ◽  
Liao Gou ◽  
Jian-Hua Su ◽  
Jinhai Huang

A series of novel hole transport materials for organic light-emitting diodes (OLEDs) based on 9,14-diphenyl-9,14-dihydrodibenzo[a,c]phenazine were synthesized and characterized by 1H NMR and 13C NMR, mass spectrometry and single crystal structure analysis methodologies.

2011 ◽  
Vol 306-307 ◽  
pp. 206-210
Author(s):  
Qing Yu Ma ◽  
Rui Fang Guan ◽  
Guo Zhong Li

Two novel silicon-centered benzimidazole derivatives, Bis(4-(benzimidazol-1-yl)phenyl) dimethylsilane (1) and Bis(3-(benzimidazol-1-yl)phenyl)dimethylsilane (2) have been synthesized and determined by IR, 1H NMR, 13C NMR and mass spectroscopy. These compounds have high thermal stability and are fluorescent with emission in the region of violet to blue, which could be potentially applied as blue emitters in organic light-emitting diodes (OLEDs) display.


Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 554
Author(s):  
Taeshik Earmme

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.


2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Nguyen Nang Dinh ◽  
Do Ngoc Chung ◽  
Tran Thi Thao ◽  
David Hui

Polymeric nanocomposite films from PEDOT and MEH-PPV embedded with surface modified TiO2nanoparticles for the hole transport layer and emission layer were prepared, respectively, for organic emitting diodes (OLEDs). The composite of MEH-PPV+nc-TiO2was used for organic solar cells (OSCs). The characterization of these nanocomposites and devices showed that electrical (I-Vcharacteristics) and spectroscopic (photoluminescent) properties of conjugate polymers were enhanced by the incorporation of nc-TiO2in the polymers. The organic light emitting diodes made from the nanocomposite films would exhibit a larger photonic efficiency and a longer lasting life. For the organic solar cells made from MEH-PPV+nc-TiO2composite, a fill factor reached a value of about 0.34. Under illumination by light with a power density of 50 mW/cm2, the photoelectrical conversion efficiency was about 0.15% corresponding to an open circuit voltageVoc= 0.126 V and a shortcut circuit current densityJsc= 1.18 mA/cm2.


2012 ◽  
Vol 9 (5) ◽  
pp. 399-406
Author(s):  
Do Chung ◽  
Nguyen Dinh ◽  
Tran Thao ◽  
Nguyen Nam ◽  
Tran Trung ◽  
...  

Polymeric nanocomposite films from PEDOT and MEH-PPV embedded with surface modified TiO2 nanoparticles were prepared, respectively for the hole transport layer (HTL) and emission layer (EL) in Organic Light Emitting Diodes (OLED). The composite of MEH-PPV + nc-TiO2 was used for Organic Solar Cells (OCS). The results from the characterization of the properties of the nanocomposites and devices showed that electrical (I-V characteristics) and spectroscopic (photoluminescent) properties of the conjugate polymers were enhanced due to the incorporation of nc-TiO2 in the polymers. The OLEDs made from the nanocomposite films would exhibit a larger photonic efficiency and a longer lasting life. For the OSC made from MEH-PPV + nc-TiO2 composite, the fill factor (FF) reached a value as high as 0.34. Under illumination of light with a power density of 50 mW/cm2, the photoelectrical conversion efficiency (PEC) was found to be of 0.15% corresponding to an open circuit voltage VOC = 1.15 V and a short-cut circuit current density JSC = 0.125 mA/cm2.


2011 ◽  
Vol 189-193 ◽  
pp. 42-46
Author(s):  
You Wang Hu ◽  
Xiao Yan Sun ◽  
Jian Duan

Organic light-emitting diodes (OLEDs) with inserting an ultrathin sol–gel titanium oxide (TiO2) buffer layer between the ITO anode and hole transport layer (HTL) were fabricated. The carrier injection and the device efficiency were affected by surface morphology of TiO2, which was changed by different plasma pre-treatment of ITO. Treated by CF4 plasma, the TiO2 layer is the smoothest, and treated by H2 plasma it is like island. The TiO2 layer like island is favor of carrier injection from the anode, which was attributed to the point discharged.


2009 ◽  
Vol 2009 (7) ◽  
pp. 437-439 ◽  
Author(s):  
Sara Tarighi ◽  
Alireza Abbasi ◽  
Sara Zamanian ◽  
Alireza Badiei ◽  
Mahmood Ghoranneviss

3-Chlorobenzo[b]thiophene-2-carbonyl chloride was synthesised from cinnamic acid and thionyl chloride. The single crystal X-ray structure determination confirmed the earlier proposed structure and the product was further characterised by 1H NMR, 13C NMR and mass spectrometry. The X-ray structure determination revealed two sets of symmetry related molecules along the b-axis that are loosely connected by relatively weak CH…π ( 3.626, 3.628 Å) interactions, giving rise to two infinite chains. The packing structure is dominated by Van der Waals forces between these chains. No significant π–π interactions are found in the crystal structure.


1997 ◽  
Vol 488 ◽  
Author(s):  
George M. Daly ◽  
Hideyuki Murata ◽  
Charles D. Merritt ◽  
Zakya H. Kafafi ◽  
Hiroshi Inada ◽  
...  

AbstractEnhanced performance has been observed for plastic molecular organic light emitting diodes (MOLEDs) consisting of two to four organic layers sequentially vacuum vapor deposited onto patterned indium-tin oxide (ITO) on polyester films. For all device structures studied, the performance of plastic diodes is comparable to or better than their analogs on glass substrates. At 100 A/m2, a luminous power efficiency of 4.4 lm/W and external quantum yield of 2.7% are measured for a device structure consisting of two hole transport layers, a doped emitting layer and an electron transport layer on a polyester substrate. The same device made on a silica substrate has a luminous power efficiency of 3.5 lm/W and external quantum yield of 2.3%. Electrical and optical performance for comparable device structures has been characterized by current-voltage-luminance measurements and electroluminescence spectra collected normal to the emitting surface. In addition, an integrating sphere was used to collect the total light emitted and to determine the optical output coupling on glass versus plastic substrates.


2004 ◽  
Vol 829 ◽  
Author(s):  
Ali N. Rashid ◽  
Donald C. Craig

Tris-(8-hydroxyquinoline) aluminum III (Alq3) is a stable metal chelate that has received a great deal of attention over the past years due to its use in the fabrication of organic light emitting diodes (OLED).[1,2] Despite all the interest in this remarkable material very little information on its' solid-state properties and packing exists. Nearly all of the available information comes from studies that have been carried out on vacuum deposited thin films.[1]


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