Ryo Nagata

ORCID: 0000-0002-1367-5424
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Research Areas
  • Optical measurement and interference techniques
  • Advanced Measurement and Metrology Techniques
  • Organic Light-Emitting Diodes Research
  • Organic Electronics and Photovoltaics
  • Surface Roughness and Optical Measurements
  • Advanced Fiber Optic Sensors
  • Optical Polarization and Ellipsometry
  • Flow Measurement and Analysis
  • Conducting polymers and applications
  • Advanced Measurement and Detection Methods
  • Digital Holography and Microscopy
  • Luminescence and Fluorescent Materials
  • Advanced Sensor and Energy Harvesting Materials
  • Advancements in Photolithography Techniques
  • Lanthanide and Transition Metal Complexes
  • Advanced Surface Polishing Techniques
  • Adhesion, Friction, and Surface Interactions
  • Thermography and Photoacoustic Techniques
  • Tribology and Lubrication Engineering
  • Underwater Acoustics Research
  • Engineering Technology and Methodologies
  • Molecular spectroscopy and chirality
  • Orthodontics and Dentofacial Orthopedics
  • Semiconductor Quantum Structures and Devices
  • Infrared Thermography in Medicine

Kyushu University
1963-2024

Chiba University
2010-2024

Waseda University
2011-2018

Nihon University
2013-2015

Osaka Prefecture University
1979-1988

Osaka University
1981

Abstract Organic light-emitting diodes have become a mainstream display technology because of their desirable features. Third-generation electroluminescent devices that emit light through mechanism called thermally activated delayed fluorescence are currently garnering much attention. However, unsatisfactory device stability is still an unresolved issue in this field. Here we demonstrate electron-transporting n-type hosts, which typically include acceptor moiety chemical structure, the...

10.1038/s41467-017-02419-x article EN cc-by Nature Communications 2017-12-16

Abstract Near‐IR organic light‐emitting diodes (NIR‐OLEDs) are potential light‐sources for various sensing applications as OLEDs have unique features such ultra‐flexibility and low‐cost fabrication. However, the low external electroluminescence (EL) quantum efficiency (EQE) of NIR‐OLEDs is a critical obstacle applications. Here, we demonstrate highly efficient NIR emitter with thermally activated delayed fluorescence (TADF) its application to NIR‐OLEDs. The NIR‐TADF emitter, TPA‐PZTCN, has...

10.1002/anie.202016089 article EN Angewandte Chemie International Edition 2021-01-15

This paper proposes a method for measuring distance larger than the wavelength of light with an interferometer using laser diode. uses fact that emitted diode varies in proportion to diode's injection current. The phase difference between two interfering beams due sinusoidal variation wavelength. is detected by optical heterodyne method. magnitude proportional and shift. If shift known, can be obtained from measurement variation. kind multiwavelength interferometry single source. We have...

10.1364/ao.25.002976 article EN Applied Optics 1986-09-01

Harvesting of both triplets and singlets yields electroluminescence quantum efficiencies nearly 100% in organic light-emitting diodes (OLEDs), but the production efficiency excitons that can undergo radiative decay is theoretically limited to electron-hole pairs. Here, breaking this limit by exploiting singlet fission an OLED reported. Based on dependence intensity applied magnetic field, it confirmed produced a rubrene host matrix are emitted as near-infrared (NIR) erbium(III)...

10.1002/adma.201801484 article EN Advanced Materials 2018-07-05

Discussion is made of calculational reconstruction refractive index distribution from "multidirectional interferograms." Two approximate calculation formulae are given for two-dimensional case. One derived using the Born approximation and corresponds to a generalization formula in X-ray structure analysis. The other obtained Rytov's straight path approximation.

10.7567/jjaps.14s1.379 article EN Japanese Journal of Applied Physics 1975-01-01

The distribution of refractive indices in the crystalline lenses rabbits was measured with a newly developed optical system. assumed to be represented by n=n0-[Z2/A2+(X2+Y2)/B2],where n0 is index at center, Z, X, and Y are coordinates, A B constants. Longitudinal spherical aberrations were calculated ray tracing on models defined above equation, it found that such lens plays very important role decreasing aberration increasing power.

10.1364/josa.58.001125 article EN Journal of the Optical Society of America 1968-08-01

A tenfold improvement in the external electroluminescence quantum efficiency of NIR electrophosphorescence is demonstrated compared to devices with conventional fluorescent materials as host, by applying concept thermally activated delayed fluorescence achieve an emitter layer capable efficient spin conversion. This device architecture can maximize performance organic-semiconductor-based light source.

10.1002/adma.201604265 article EN Advanced Materials 2016-11-18

Abstract The impact of magnetic field effects on the electroluminescence organic light-emitting diodes is commonly used to characterize exciton dynamics such as generation, annihilation, and performance degradation. However, interpreting these challenging. Here, we show that in can be understood terms response device characteristics derived from polaron-pair triplet quenching processes, triplet-polaron interactions triplet-triplet annihilation. Device degradation shows a clear relationship...

10.1038/s43246-020-0019-0 article EN cc-by Communications Materials 2020-04-24

Abstract Near‐IR organic light‐emitting diodes (NIR‐OLEDs) are potential light‐sources for various sensing applications as OLEDs have unique features such ultra‐flexibility and low‐cost fabrication. However, the low external electroluminescence (EL) quantum efficiency (EQE) of NIR‐OLEDs is a critical obstacle applications. Here, we demonstrate highly efficient NIR emitter with thermally activated delayed fluorescence (TADF) its application to NIR‐OLEDs. The NIR‐TADF emitter, TPA‐PZTCN, has...

10.1002/ange.202016089 article EN Angewandte Chemie 2021-01-15

Get PDF Email Share with Facebook Tweet This Post on reddit LinkedIn Add to CiteULike Mendeley BibSonomy Citation Copy Text Koichi Iwata and Ryo Nagata, "Calculation of Three-Dimensional Refractive-Index Distribution from Interferograms*," J. Opt. Soc. Am. 60, 133-135 (1970) Export BibTex Endnote (RIS) HTML Plain alert Save article

10.1364/josa.60.000133 article EN Journal of the Optical Society of America 1970-01-01

A method for measuring absolute distance by the wavelength shift of laser diode light has previously been proposed. In this work three serious systematic error sources are discussed and some discussion is confirmed experiment. The optical feedback effect, longitudinal mode distribution light, unwanted reflected from devices (coherent noise). effect influences emitted light. causes periodic dependent on measured distance, maximum determined change in intensity ratio submodes to main mode....

10.1364/ao.26.001654 article EN Applied Optics 1987-05-01

Mo/Si multilayer mirrors are used for extreme ultraviolet (EUV) lithography. The formation of hydrogen-induced blisters in the is a problem that reduces reflectance mirror. To evaluate blister-resistance EUV mirrors, blister processes multilayers with capping layer were investigated using high-frequency hydrogen plasma system as ion source under varying exposure conditions. As result, it was observed by low-energy irradiation about 10 eV increases blister-occupied area, depending on amount...

10.1585/pfr.17.1406005 article EN Plasma and Fusion Research 2022-02-21

A simple method for measuring the displacement-slope distribution is proposed, and its usefulness verified experimentally. In this we use a single-aperture recording system with only one grating. The grating forms spatial carrier of high frequency inside speckles in image also shears images. sheared images are doubly recorded on photoplate before after deformation object. Clear fringes obtained by filtering plate. This gives us indicating slope distribution. It experimentally that these...

10.1364/ao.23.000247 article EN Applied Optics 1984-01-15

Simultaneous achievement of both high electroluminescence efficiency and operational stability in organic light-emitting diodes (OLEDs) is required for their use various practical applications. Although OLEDs based on thermally activated delayed fluorescence-assisted fluorescence (TAF) are considered to possess a promising device architecture exploit the full potential OLEDs, such systems still requires further improvement. In this study, quaternary emission layer consisting combination TAF...

10.1021/acsami.0c15208 article EN ACS Applied Materials & Interfaces 2020-10-26

A scattered-light method using depolarized incident light is used for nondestructive measurement of 3-D stress distribution. In this method, scattered on the plane sheet in interior photoelastic model observed from direction perpendicular to plane. By optical slicing with such a distribution can be determined each slice. Experiments case frozen sphere under diametral compression are made show usefulness proposed method.

10.1364/ao.18.000321 article EN Applied Optics 1979-02-01

Highly conductive poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT : PSS) attracts a strong attention as transparent electrode material since it may replace indium tin oxide (ITO) electrodes used in many organic semiconductor devices. However, PEDOT PSS films have been usually deposited using acidic precursors, which caused long term device degradation well safety issues during fabrication processes. This paper firstly reports application of highly on polyethylene...

10.1587/transele.e98.c.411 article EN IEICE Transactions on Electronics 2015-01-01

In this paper, we report on bulk heterojunction organic solar cells fabricated highly conductive poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOTPSS) electrodes directly deposited a flexible polyethylene terephthalate (PET) substrate. The PEDOTPSS layers were using neutralized (pH~7) solution. sheet resistance of the films became more than two orders magnitudes smaller after step treatments that without treatments. include 1) spin coating solution containing 5% dimethyl...

10.1109/am-fpd.2014.6867202 article EN 2014-07-01

In this paper a method of determining dielectric tensor field in weakly inhomogeneous anisotropic medium with optical activity is presented on the basis an electro-optical theory light propagation such medium. The divided into many identical cubic cells and each cell has some unknown parameters to be determined. Its approximately represented by all cells. evaluation these from data, which are collected recording amplitudes relative phase retardations wave fronts passing through various...

10.1364/josa.69.000604 article EN Journal of the Optical Society of America 1979-04-01

A method for measuring flow velocity distribution in the interior of a transparent fluid is proposed. The utilizes thin sheet laser light, which illuminates containing small scattering particles. double-exposure hologram made with scattered light as signal wave. In reconstructed image we can observe interference fringes correspond to particle displacements between two exposures and consequently velocity. Simple experiments were performed that confirmed usefulness method. discussion relation...

10.1364/josa.67.001117 article EN Journal of the Optical Society of America 1977-08-01
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