Simple Structure and High Efficiency Phosphorescent OLEDs Using Narrow Band-gap Bipolar Host Material

2012 ◽  
Vol 1435 ◽  
Author(s):  
Young Hoon Son ◽  
Jang Hyuk Kwon
Keyword(s):  
Band Gap ◽  
External Quantum Efficiency ◽  
Simple Structure ◽  
High Efficiency ◽  
Narrow Band ◽  
Triplet Energy ◽  
Energy Hole ◽  
Host Materials ◽  
Hole Transporting ◽  
Hole Transporting Material

ABSTRACTWe report high-efficiency phosphorescent blue OLEDs with an organic three stacked structure. Using a high-triplet-energy-hole transporting material of TAPC and a high-triplet-energy-electron transporting material of TmPyPB, the organic three stacked structure has been realized with three new narrow band-gap blue host materials. These host materials have bipolar characteristics and high triplet energy of >2.8 eV. Very low onset voltages of 2.8~3.0 V and driving voltages of 4.2~4.6 V to obtain a brightness of 1000 cd/m2 are achieved in this three stacked device configuration. Maximum external quantum efficiency above 20% is reported.

scholarly journals δ-Carboline-based bipolar host materials for deep blue thermally activated delayed fluorescence OLEDs with high efficiency and low roll-off characteristic

RSC Advances ◽  
2018 ◽  
Vol 8 (31) ◽  
pp. 17025-17033 ◽  
Author(s):  
Ji Su Moon ◽  
Dae Hyun Ahn ◽  
Si Woo Kim ◽  
Seung Yeon Lee ◽  
Ju Young Lee ◽  
...  
Keyword(s):  
External Quantum Efficiency ◽  
High Efficiency ◽  
Delayed Fluorescence ◽  
Triplet Energy ◽  
Characteristic P ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Deep Blue ◽  
Host Materials ◽  
Low Efficiency

We report two new bipolar host materials with ~3.0 eV high triplet energy. Fabricated deep blue TADF OLEDs with these hosts exhibited external quantum efficiency as high as 22.9% and low efficiency roll-off (19.2% at 1000 cd m–2).

scholarly journals High efficiency blue organic light-emitting diodes with below-bandgap electroluminescence

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Maria Vasilopoulou ◽  
Abd. Rashid bin Mohd Yusoff ◽  
Matyas Daboczi ◽  
Julio Conforto ◽  
Anderson Emanuel Ximim Gavim ◽  
...  
Keyword(s):  
High Efficiency ◽  
Light Emitting Diodes ◽  
High Mobility ◽  
Organic Light Emitting Diodes ◽  
Triplet Energy ◽  
Material Interface ◽  
Light Emitting ◽  
Thermally Activated ◽  
Organic Light ◽  
Hole Transporting

AbstractBlue organic light-emitting diodes require high triplet interlayer materials, which induce large energetic barriers at the interfaces resulting in high device voltages and reduced efficiencies. Here, we alleviate this issue by designing a low triplet energy hole transporting interlayer with high mobility, combined with an interface exciplex that confines excitons at the emissive layer/electron transporting material interface. As a result, blue thermally activated delay fluorescent organic light-emitting diodes with a below-bandgap turn-on voltage of 2.5 V and an external quantum efficiency (EQE) of 41.2% were successfully fabricated. These devices also showed suppressed efficiency roll-off maintaining an EQE of 34.8% at 1000 cd m−2. Our approach paves the way for further progress through exploring alternative device engineering approaches instead of only focusing on the demanding synthesis of organic compounds with complex structures.

scholarly journals Pyridinyl-Carbazole Fragments Containing Host Materials for Efficient Green and Blue Phosphorescent OLEDs

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4615
Author(s):  
Dovydas Blazevicius ◽  
Daiva Tavgeniene ◽  
Simona Sutkuviene ◽  
Ernestas Zaleckas ◽  
Ming-Ruei Jiang ◽  
...  
Keyword(s):  
Current Efficiency ◽  
Quantum Efficiency ◽  
External Quantum Efficiency ◽  
Power Efficiency ◽  
Triplet Energy ◽  
New Host ◽  
High Brightness ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Host Materials

Pyridinyl-carbazole fragments containing low molar mass compounds as host derivatives H1 and H2 were synthesized, investigated, and used for the preparation of electro-phosphorescent organic light-emitting devices (PhOLEDs). The materials demonstrated high stability against thermal decomposition with the decomposition temperatures of 361–386 °C and were suitable for the preparation of thin amorphous and homogeneous layers with very high values of glass transition temperatures of 127–139 °C. It was determined that triplet energy values of the derivatives are, correspondingly, 2.82 eV for the derivative H1 and 2.81 eV for the host H2. The new derivatives were tested as hosts of emitting layers in blue, as well as in green phosphorescent OLEDs. The blue device with 15 wt.% of the iridium(III)[bis(4,6-difluorophenyl)-pyridinato-N,C2′]picolinate (FIrpic) emitter doping ratio in host material H2 exhibited the best overall characteristics with a power efficiency of 24.9 lm/W, a current efficiency of 23.9 cd/A, and high value of 10.3% of external quantum efficiency at 100 cd/m2. The most efficient green PhOLED with 10 wt% of Ir(ppy)3 {tris(2-phenylpyridine)iridium(III)} in the H2 host showed a power efficiency of 34.1 lm/W, current efficiency of 33.9 cd/A, and a high value of 9.4% for external quantum efficiency at a high brightness of 1000 cd/m2, which is required for lighting applications. These characteristics were obtained in non-optimized PhOLEDs under an ordinary laboratory atmosphere and could be improved in the optimization process. The results demonstrate that some of the new host materials are very promising components for the development of efficient phosphorescent devices.

scholarly journals Tunable Narrow Band Gap Absorbers For Ultra High Efficiency Solar Cells

2012 ◽  
Author(s):  
Salah M. Bedair ◽  
◽  
John R. Hauser ◽  
Nadia Elmasry ◽  
Peter C. Colter ◽  
...  
Keyword(s):  
Solar Cells ◽  
Band Gap ◽  
High Efficiency ◽  
Narrow Band ◽  
High Efficiency Solar Cells

Stable perovskite solar cells with efficiency exceeding 24.8% and 0.3-V voltage loss

Science ◽  
2020 ◽  
Vol 369 (6511) ◽  
pp. 1615-1620 ◽  
Author(s):  
Mingyu Jeong ◽  
In Woo Choi ◽  
Eun Min Go ◽  
Yongjoon Cho ◽  
Minjin Kim ◽  
...  
Keyword(s):  
High Efficiency ◽  
Noncovalent Interactions ◽  
Energy Levels ◽  
Perovskite Solar Cells ◽  
Structure Property ◽  
Large Area ◽  
Long Term Stability ◽  
Voltage Loss ◽  
Hole Transporting ◽  
Hole Transporting Material

Further improvement and stabilization of perovskite solar cell (PSC) performance are essential to achieve the commercial viability of next-generation photovoltaics. Considering the benefits of fluorination to conjugated materials for energy levels, hydrophobicity, and noncovalent interactions, two fluorinated isomeric analogs of the well-known hole-transporting material (HTM) Spiro-OMeTAD are developed and used as HTMs in PSCs. The structure–property relationship induced by constitutional isomerism is investigated through experimental, atomistic, and theoretical analyses, and the fabricated PSCs feature high efficiency up to 24.82% (certified at 24.64% with 0.3-volt voltage loss), along with long-term stability in wet conditions without encapsulation (87% efficiency retention after 500 hours). We also achieve an efficiency of 22.31% in the large-area cell.

scholarly journals Low cost triazatruxene hole transporting material for >20% efficiency perovskite solar cells

2019 ◽  
Vol 7 (18) ◽  
pp. 5235-5243 ◽  
Author(s):  
Arthur Connell ◽  
Zhiping Wang ◽  
Yen-Hung Lin ◽  
Peter C. Greenwood ◽  
Alan A. Wiles ◽  
...  
Keyword(s):  
Solar Cells ◽  
High Efficiency ◽  
Low Cost ◽  
Perovskite Solar Cells ◽  
Hole Transporting ◽  
Hole Transporting Material ◽  
Hole Transporting Materials

Organic hole-transporting materials (HTM) have shown excellent ability in achieving high efficiency perovskite solar cells.

Simultaneous realization of high-efficiency, low-drive voltage, and long lifetime TADF OLEDs by multifunctional hole-transporters

2020 ◽  
Vol 8 (21) ◽  
pp. 7200-7210 ◽  
Author(s):  
Takahiro Kamata ◽  
Hisahiro Sasabe ◽  
Nozomi Ito ◽  
Yoshihito Sukegawa ◽  
Ayato Arai ◽  
...  
Keyword(s):  
High Efficiency ◽  
Triplet Energy ◽  
Energy Hole ◽  
Light Emitting ◽  
Drive Voltage ◽  
Light Emitting Devices ◽  
Thermally Activated ◽  
Highly Efficient ◽  
Organic Light ◽  
Long Lifetime

A smart high-triplet energy hole-transporter exhibits significant stability in the anion state realizing record-breaking highly efficient and long-living thermally activated delayed fluorescent (TADF) organic light-emitting devices (OLEDs).

Hole transporting materials based on benzodithiophene and dithienopyrrole cores for efficient perovskite solar cells

2018 ◽  
Vol 6 (14) ◽  
pp. 5944-5951 ◽  
Author(s):  
R. Sandoval-Torrientes ◽  
I. Zimmermann ◽  
J. Calbo ◽  
J. Aragó ◽  
J. Santos ◽  
...  
Keyword(s):  
Solar Cells ◽  
High Efficiency ◽  
Perovskite Solar Cells ◽  
Reorganization Energy ◽  
Hole Transporting ◽  
Hole Transporting Material ◽  
Hole Transporting Materials

High efficiency (18.1%) perovskite solar cells are demonstrated by using a hole transporting material with very low reorganization energy (λ).

Toward high-efficiency, hysteresis-less, stable perovskite solar cells: unusual doping of a hole-transporting material using a fluorine-containing hydrophobic Lewis acid

2018 ◽  
Vol 11 (8) ◽  
pp. 2035-2045 ◽  
Author(s):  
Junsheng Luo ◽  
Jianxing Xia ◽  
Hua Yang ◽  
Lingling Chen ◽  
Zhongquan Wan ◽  
...  
Keyword(s):  
Solar Cells ◽  
Lewis Acid ◽  
High Efficiency ◽  
State Of The Art ◽  
Perovskite Solar Cells ◽  
Hole Transporting ◽  
Hole Transporting Material ◽  
Effective Dopant

A fluorine-containing hydrophobic Lewis acid is employed as an effective dopant for PTAA to replace state-of-the-art Li-TFSI/t-BP in PSCs.

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