A5069817236- Organic Light-Emitting Diodes Research
- Perovskite Materials and Applications
- Organic Electronics and Photovoltaics
- Conducting polymers and applications
- Quantum Dots Synthesis And Properties
- Luminescence and Fluorescent Materials
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Nanocluster Synthesis and Applications
- Thin-Film Transistor Technologies
- Green IT and Sustainability
- Advanced Combustion Engine Technologies
- Chalcogenide Semiconductor Thin Films
- Molecular Junctions and Nanostructures
- Luminescence Properties of Advanced Materials
- Optical properties and cooling technologies in crystalline materials
- Liquid Crystal Research Advancements
- Solid-state spectroscopy and crystallography
- Fluid Dynamics and Heat Transfer
- Semiconductor Quantum Structures and Devices
- Technical Engine Diagnostics and Monitoring
- GaN-based semiconductor devices and materials
- Semiconductor Lasers and Optical Devices
- Advanced Surface Polishing Techniques
- Catalytic Cross-Coupling Reactions
Yamagata University
2016-2025
Yamagata University Hospital
2015-2024
Yonezawa Technical High School
2015-2020
Yamagata Research Institute Of Technology
2018
Kogakuin University
2002
Gunma University
2002
Tokyo Denki University
2001
National Institute of Technology, Tokyo College
1995
Tokai University
1995
Ibaraki University
1979
Two pyridine-containing triphenylbenzene derivatives of 1,3,5-tri(m-pyrid- 3-yl-phenyl)benzene (TmPyPB) and 1,3,5-tri(p-pyrid-3-yl-phenyl) benzene (TpPyPB) (see figure) with high electron mobility triplet energy level were designed synthesized. Highly efficient blue green phosphorescent OLEDs achieved by using TmPyPB TpPyPB as an electron-transport layer, respectively.
All inorganic perovskites quantum dots (PeQDs) have attracted much attention for used in thin film display applications and solid-state lighting applications, owing to their narrow band emission with high photoluminescence yields (PLQYs), color tunability, solution processability. Here, we fabricated low-driving-voltage high-efficiency CsPbBr3 PeQDs light-emitting devices (PeQD-LEDs) using a washing process an ester solvent containing butyl acetate (AcOBu) remove excess ligands from the...
Light-emitting diodes (LEDs) based on perovskite semiconductor materials with tunable emission wavelength in visible light range as well narrow linewidth are potential competitors among current light-emitting display technologies, but still suffer from severe instability driven by electric field. Here, we develop a stable, efficient and high-color purity hybrid LED tandem structure combining the commercial organic technologies to accelerate practical application of perovskites. Perovskite...
An ultra high efficiency blue organic light-emitting device using wide-energy-gap electron-transport material containing 3,5-dipyridylphenyl moieties and phosphorescent emitter, FIrpic, was developed. The optimized showed extremely power efficiencies of 56 lm/W (53 cd/A) at 100 cd/m2 42 (46 1000 without light outcoupling enhancement.
Abstract Three triphenyl benzene derivatives of 1,3,5‐tri( m ‐pyrid‐2‐yl‐phenyl)benzene (Tm2PyPB), ‐pyrid‐3‐yl‐phenyl)benzene (Tm3PyPB) and ‐pyrid‐4‐yl‐phenyl)benzene (Tm4PyPB), containing pyridine rings at the periphery, are developed as electron‐transport hole/exciton‐blocking materials for iridium(III) bis(4,6‐(di‐fluorophenyl)pyridinato‐ N , C 2′ )picolinate (FIrpic)‐based blue phosphorescent organic light‐emitting devices. Their highest occupied molecular orbital lowest unoccupied...
Abstract Tris-[3-(3-pyridyl)mesityl]borane (3TPYMB) with high triplet excited energy level was synthesized and investigated as an electron-transport material for organic light-emitting devices (OLEDs). Larger current density higher luminance were observed the OLED using 3TPYMB, compared a conventional material, tris(8-quinolinolato)aluminum (Alq3).
A series of 2-methylpyrimidine skeleton-based electron-transporting derivatives (BPyMPM) are designed and synthesized to investigate the influence substituted pyridine rings on physical properties electron mobilities (μe). The only structural difference is position rings. melting point (Tm) B4PyMPM estimated be ca. 50 °C higher than that B3PyMPM, 120 B2PyMPM. ionization potential observed increase in order B2PyMPM (6.62 eV) < B3PyMPM (6.97 (7.30 eV), measured using ultraviolet photoelectron...
Solution-processed phosphorescent tandem organic light-emitting devices (OLEDs) exhibit extremely high efficiencies (94 cd A(-1) ) and 26% external quantum efficiency (EQE) at 5000 m(-2) for green 69 28% EQE white devices. Development of these highly efficient solution-processed tandem-OLEDs with inverted device structure paves the way to printable, low-cost, large-area lighting.
Cesium lead halide (CsPbX3, X = Cl, Br, or I) perovskite quantum dots (QDs) are known as ionic nanocrystals, and their optical properties greatly affected by the washing solvent used during purification process. Here, we demonstrate process of CsPbBr3 QDs using low-dielectric-constant solvents to completely remove impurities, such reaction desorbed ligands. The use ether diethylene glycol dimethyl (diglyme), having a low dielectric constant ε 7.23, poor for reprecipitation allowed multiple...
2-Phenylpyrimidine skeleton-based multifunctional electron-transport materials are designed and synthesized. By using these green phosphorescent emitter, fac-tris(2-phenylpyridine)iridium [Ir(ppy)(3)], extremely efficient organic light-emitting devices developed. The show the efficiencies of 128 lm W(-1) (105 cd A(-1)) at 100 m(-2) 96 (99 1000 m(-2).
Multi-organic light-emitting devices comprising two units stacked in series through a charge-generation layer are fabricated by solution processes. A zinc oxide nanoparticles/polyethyleneimine bilayer is used as the electron-injection and phosphomolybdic acid layer. Appropriate choice of solvents during spin-coating each ensures nine-layered structure
Poly(N-vinylcarbazole) undergoes cross-linking to highly solvent-resistant films through an oxidative coupling reaction, for which annealing process takes only 3 min at 110 °C. This reaction allows the construction of a solution-processed multilayer OLED without time-consuming process. The maximum external quantum efficiency reaches 18%, and remains 17%, even high brightness 10 000 cd m(-2) all-solution-processed blue OLEDs.
Abstract Use of the intrinsic optoelectronic functions organic semiconductor films has not yet reached its full potential, mainly because primitive methodology used to control molecular aggregation state in amorphous during vapor deposition. Here, a universal engineering is presented orientation; this strategically uses noncovalent, intermolecular weak hydrogen bonds series oligopyridine derivatives. A key use two bipyridin‐3‐ylphenyl moieties, which form self‐complementary bonds, and do...
Solution-processed organic light-emitting devices (OLEDs) have progressed as potential candidates for cost-effective solid-state lighting and flat panel displays.
Abstract Metal halide perovskite nanocrystals (NCs) have been established as promising materials for light‐emitting devices (LEDs) due to their interesting optoelectrical properties, including high photoluminescence quantum yield (PLQY) and color purity with narrow full width at half maximum (FWHM). However, blue LEDs, an emission wavelength below 470 nm, require further investigation improve performance. Here, it is demonstrated that mixed‐halide CsPb(Cl/Br) 3 NCs prepared by ligand...
Abstract Mixed‐cation hybrid perovskite nanocrystal (HPNC) with high crystallinity, color purity, and tunable optical bandgap offers a practical pathway toward next‐generation displays. Herein, two‐step modified hot‐injection combined cation compositional engineering surface treatment to synthesize high‐purity cesium/formamidinium lead bromide HPNCs(Cs 1‐ x FA PbBr 3 ) is presented. The optimized Cs 0.5 light‐emitting devices (LEDs) exhibit uniform luminescence of 3500 cd m −2 prominent...
The optoelectronic properties of lead-halide perovskite quantum dots (QDs) can be tuned according to their halogen composition ratio and size effect. However, the pure red emission CsPbI3 QDs exhibits poor phase stability, thereby resulting in a transition nonphotoactive yellow at room temperature. These instabilities are accompanied by crystal strain instability QD surface, which induce ion diffusion desorption. Herein, we demonstrate precise control postsynthetic guanidinium iodide (GAI)...
A lithium quinolate complex (Liq) has high solubility in polar solvents such as alcohols and can be spin-coated onto emitting polymers, resulting a smooth surface morphology. polymer light-emitting device fabricated with Liq an electron injection layer (EIL) exhibited lower turn-on voltage higher efficiency than Cs₂CO₃ thermally evaporated Ca. The mixture of ZnO nanoparticles served efficient EIL, driving even thick films (∼10 nm), it did not require high-temperature annealing process.
In this review, we focus on current progress of LHP-QD based LEDs, issue and challenge for high efficiency stability LEDs.
We report hole-injection layers (HILs) comprising a heteropoly acid containing MoO3 units, phosphomolybdic (PMA), in organic light-emitting devices (OLEDs). PMA possesses outstanding properties, such as high solubility solvents, very low surface roughness the film state, transparency visible region, and an appropriate work function (WF), that make it suitable for HILs. also found these properties were dependent on postbaking atmosphere temperature after formation. When was baked N2, Mo...