Key host parameters for long lifetimes in phosphorescent organic light-emitting diodes: bond dissociation energy in triplet excited state

2020 ◽  
Vol 8 (5) ◽  
pp. 1697-1703 ◽  
Author(s):  
Chang Yoon Yang ◽  
Sunwoo Kang ◽  
Hyein Jeong ◽  
Ho Jin Jang ◽  
Yoonkyoo Lee ◽  
...  
Keyword(s):  
Excited State ◽  
Electron Transport ◽  
Bond Dissociation Energy ◽  
Dissociation Energy ◽  
Light Emitting Diodes ◽  
Hole Transport ◽  
Organic Light Emitting Diodes ◽  
Triplet Excited State ◽  
Light Emitting ◽  
Organic Light

Key parameters of the host for long lifetimes in phosphorescent organic light-emitting diodes were investigated by synthesizing three isomeric hosts with a carbazolylcarbazole hole transport moiety and a benzonitrile electron transport moiety.

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.

High triplet energy exciplex host derived from a CN modified carbazole based n-type host for improved efficiency and lifetime in blue phosphorescent organic light-emitting diodes

2018 ◽  
Vol 6 (38) ◽  
pp. 10308-10314 ◽  
Author(s):  
Su Kyeong Shin ◽  
Si Hyun Han ◽  
Jun Yeob Lee
Keyword(s):  
Electron Transport ◽  
Light Emitting Diodes ◽  
Hole Transport ◽  
Organic Light Emitting Diodes ◽  
Triplet Energy ◽  
Light Emitting ◽  
Type Host ◽  
Organic Light ◽  
Blue Phosphorescent ◽  
Transport Type

High triplet energy exciplexes which can improve the lifetime of blue phosphorescent organic light-emitting diodes were developed by mixing a carbazole based hole transport type host with a CN modified carbazole based electron transport type host.

scholarly journals Effects of Charge Transport Materials on Blue Fluorescent Organic Light-Emitting Diodes with a Host-Dopant System

Micromachines ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 344 ◽  
Author(s):  
Neng Liu ◽  
Sijiong Mei ◽  
Dongwei Sun ◽  
Wuxing Shi ◽  
Jiahuan Feng ◽  
...  
Keyword(s):  
Electron Transport ◽  
High Efficiency ◽  
Light Emitting Diodes ◽  
Molybdenum Trioxide ◽  
Hole Transport ◽  
Organic Light Emitting Diodes ◽  
Maximum Luminance ◽  
Light Emitting ◽  
Organic Light ◽  
Hole Transport Layers

High efficiency blue fluorescent organic light-emitting diodes (OLEDs), based on 1,3-bis(carbazol-9-yl)benzene (mCP) doped with 4,4’-bis(9-ethyl-3-carbazovinylene)-1,1’-biphenyl (BCzVBi), were fabricated using four different hole transport layers (HTLs) and two different electron transport layers (ETLs). Fixing the electron transport material TPBi, four hole transport materials, including 1,1-Bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC), N,N’-Di(1-naphthyl)-N,N’-diphenyl-(1,1’-biphenyl)-4’-diamine(NPB), 4,4’-Bis(N-carbazolyl)-1,1,-biphenyl (CBP) and molybdenum trioxide (MoO3), were selected to be HTLs, and the blue OLED with TAPC HTL exhibited a maximum luminance of 2955 cd/m2 and current efficiency (CE) of 5.75 cd/A at 50 mA/cm2, which are 68% and 62% higher, respectively, than those of the minimum values found in the device with MoO3 HTL. Fixing the hole transport material TAPC, the replacement of TPBi ETL with Bphen ETL can further improve the performance of the device, in which the maximum luminance can reach 3640 cd/m2 at 50 mA/cm2, which is 23% higher than that of the TPBi device. Furthermore, the lifetime of the device is also optimized by the change of ETL. These results indicate that the carrier mobility of transport materials and energy level alignment of different functional layers play important roles in the performance of the blue OLEDs. The findings suggest that selecting well-matched electron and hole transport materials is essential and beneficial for the device engineering of high-efficiency blue OLEDs.

Improve the Charge Balance of White Phosphorescent Organic Light Emitting Diodes Using Co-Doped Electron Transport Layer in Emitting Layer

2011 ◽  
Vol 287-290 ◽  
pp. 3051-3055
Author(s):  
Yu Sheng Tsai ◽  
Lin Ann Hong ◽  
Fuh Shyang Juang ◽  
Kuang Chih Lai ◽  
Chang Jun Lai ◽  
...  
Keyword(s):  
Electron Transport ◽  
Power Efficiency ◽  
Light Emitting Diodes ◽  
Hole Transport ◽  
Organic Light Emitting Diodes ◽  
Electron Transport Layer ◽  
Driving Voltage ◽  
Light Emitting ◽  
Organic Light ◽  
Luminance Efficiency

White phosphorescent organic light-emitting diodes (WPHOLED) with high efficiency and low driving voltage were achieved by incorporating an electron transport material (3TPYMB) into a hole transport-type host (TCTA) as a mixed-host structure. For electrons, the emitting layer is nearly barrier-free until they reach the region of exciton formation, which keeps the driving voltage low. Therefore, improved the charge carrier balance within the emitting layer and enhanced the power efficiency of device. White PHOLED at a luminance of 1000 cd/m2 shown a driving voltage of 4.38 V, luminance efficiency of 36.1 cd/A, and power efficiency of 26.4 lm/W was observed. Furthermore, the power efficiency can be improved to 34.27 lm/W, and luminance efficiency to 46.7 cd/A by attaching a brightness enhancement film (BEF).

Phenothiazine dioxide based high triplet energy host materials for blue phosphorescent organic light-emitting diodes

RSC Advances ◽  
2015 ◽  
Vol 5 (118) ◽  
pp. 97903-97909 ◽  
Author(s):  
In Ho Lee ◽  
Jun Yeob Lee
Keyword(s):  
Electron Transport ◽  
Light Emitting Diodes ◽  
Hole Transport ◽  
Organic Light Emitting Diodes ◽  
Triplet Energy ◽  
Light Emitting ◽  
Organic Light ◽  
Host Materials ◽  
Donor Acceptor ◽  
Blue Phosphorescent

Donor–acceptor type high triplet energy host materials were derived from a phenothiazine dioxide based electron transport moiety and a carbazole based hole transport moiety.

Novel Carbazole-based Multifunctional Materials with Hybridized Local and Charge-Transfer Excited State Acting as Deep Blue Emitters and Phosphorescent Hosts for Highly Efficient Organic Light-Emitting Diodes

2021 ◽  
Author(s):  
Haitao Zhou ◽  
Mengna Yin ◽  
Zhenhong Zhao ◽  
Yanqin Miao ◽  
Xin Jin ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Multifunctional Materials ◽  
Light Emitting ◽  
Highly Efficient ◽  
Deep Blue ◽  
Organic Light ◽  
Blue Emitters

In this work, two carbazole- and benzo[d]oxazole-based novel multifunctional materials with hybridized local and charge-transfer (HLCT) characteristic, namely OCI and OCT, which could act as deep-blue fluorophors and phosphorescent hosts,...

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.

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