Theoretical investigation of nitrogen-linked poly(2,7-carbazole)s as hole-transport materials for organic light emitting diodes

2011 ◽  
Vol 969 (1-3) ◽  
pp. 71-75 ◽  
Author(s):  
Ling Yi ◽  
Xueye Wang
Keyword(s):  
Theoretical Investigation ◽  
Light Emitting Diodes ◽  
Hole Transport ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Organic Light

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.

scholarly journals Study of Nanostructured Polymeric Composites Used for Organic Light Emitting Diodes and Organic Solar Cells

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Nguyen Nang Dinh ◽  
Do Ngoc Chung ◽  
Tran Thi Thao ◽  
David Hui
Keyword(s):  
Solar Cells ◽  
Organic Solar Cells ◽  
Light Emitting Diodes ◽  
Hole Transport ◽  
Organic Light Emitting Diodes ◽  
Transport Layer ◽  
Nanocomposite Films ◽  
Hole Transport Layer ◽  
Light Emitting ◽  
Organic Light

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.

Study of nanostructured polymeric composites used for organic light emitting diodes and organic solar cells

2012 ◽  
Vol 9 (5) ◽  
pp. 399-406
Author(s):  
Do Chung ◽  
Nguyen Dinh ◽  
Tran Thao ◽  
Nguyen Nam ◽  
Tran Trung ◽  
...  
Keyword(s):  
Solar Cells ◽  
Organic Solar Cells ◽  
Light Emitting Diodes ◽  
Hole Transport ◽  
Organic Light Emitting Diodes ◽  
Transport Layer ◽  
Nanocomposite Films ◽  
Hole Transport Layer ◽  
Light Emitting ◽  
Organic Light

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.

Plastic Multilayered Molecular Organic Light Emitting Diodes

1997 ◽  
Vol 488 ◽  
Author(s):  
George M. Daly ◽  
Hideyuki Murata ◽  
Charles D. Merritt ◽  
Zakya H. Kafafi ◽  
Hiroshi Inada ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Power Efficiency ◽  
Light Emitting Diodes ◽  
Hole Transport ◽  
Organic Light Emitting Diodes ◽  
Electron Transport Layer ◽  
Light Emitting ◽  
Organic Light ◽  
Device Structures ◽  
External Quantum Yield

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.

Simulation and Optimization of C60-Based Organic Light-Emitting Diodes

2021 ◽  
Vol 1026 ◽  
pp. 142-146
Author(s):  
Shuo Wang
Keyword(s):  
Indium Tin Oxide ◽  
Light Emitting Diodes ◽  
Hole Transport ◽  
Organic Light Emitting Diodes ◽  
Transport Layer ◽  
Hole Transport Layer ◽  
Optical Parameters ◽  
Light Emitting ◽  
Simulation And Optimization ◽  
Organic Light

In this work we present a detailed analysis of the current-voltage variance from tris(8-hydroxyquinoline)aluminum (Alq3) based organic light emitting diodes using general-purpose photovoltaic device model (GPVDM) software as a function of: the choice of C60, the thickness of emission layer and hole-transport layer. The electrical and optical parameters of all layers were extracted from the material directory available in GPVDM. The calculations fully consider dispersion in glass substrate, indium tin oxide anode, the organic layers as well as the dispersion in the metal cathode. As expected, applied voltage was strongly dependent on the thickness of the function layer inside the devices. Finally, guidelines for designing devices with optimum turn-on voltage and thickness are presented.

Efficient blue-green molecular organic light emitting diodes based on novel silole derivatives

2002 ◽  
Vol 725 ◽  
Author(s):  
Leonidas C. Palilis ◽  
Hideyuki Murata ◽  
Antti J. Mäkinen ◽  
Manabu Uchida ◽  
Zakya H. Kafafia
Keyword(s):  
Electron Transport ◽  
Quantum Efficiency ◽  
Light Emitting Diodes ◽  
Hole Transport ◽  
Organic Light Emitting Diodes ◽  
Operating Voltage ◽  
High Electron ◽  
Blue Fluorescence ◽  
Light Emitting ◽  
Organic Light

AbstractWe report on highly efficient molecular organic light-emitting diodes (MOLEDs) using two novel silole derivatives as emissive and electron transport materials. A silole derivative, namely 2,5-di-(3-biphenyl)-1,1-dimethyl-3,4-diphenylsilacyclopentadiene (PPSPP), which shows blue fluorescence with a high photoluminescence quantum yield of 85% in the solid state, was used as the emissive material. Another silole derivative, namely 2,5-bis-(2‘2“-bipyridin-6-yl)-1,1- dimethyl-3,4-diphenylsilacyclopentadiene (PyPySPyPy), that exhibits a non-dispersive high electron mobility of 2x10-4 cm2/Vsec was used as the electron transport material. MOLEDs using these two siloles and a common hole transport material show blue-green emission centered at 495 nm. This red-shifted electroluminescence (EL) band relative to the blue fluorescence of PPSPP is assigned to a PPSPP:NPB exciplex. A low operating voltage of 4.5 V was measured at a luminance of 100 cd/m2 and an EL quantum efficiency of 3.4% was achieved at 100 A/m2. To our knowledge, this is the highest EL quantum efficiency ever reported based on exciplex emission.

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