Hisao Ishii
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View article: Using optical tweezers to simultaneously trap, charge and measure the charge of a microparticle in air
Using optical tweezers to simultaneously trap, charge and measure the charge of a microparticle in air Open
Optical tweezers are widely used as a highly sensitive tool to measure forces on micron-scale particles. One such application is the measurement of the electric charge of a particle, which can be done with high precision in liquids, air, o…
View article: 0068 Skin eruption shape-based pathological state inference for personalized treatment in chronic spontaneous urticaria
0068 Skin eruption shape-based pathological state inference for personalized treatment in chronic spontaneous urticaria Open
View article: Spectroscopic Methods to Measure Low-energy Photoelectron from Solids in Medium Vacuum Using a Classic Retarding Field Analyzer
Spectroscopic Methods to Measure Low-energy Photoelectron from Solids in Medium Vacuum Using a Classic Retarding Field Analyzer Open
View article: Impact of Nitrogen Doping on Leakage Current of p‐Type Cu <sub>2</sub> O‐Based pn Junctions for Ga <sub>2</sub> O <sub>3</sub> Power Device Applications
Impact of Nitrogen Doping on Leakage Current of p‐Type Cu <sub>2</sub> O‐Based pn Junctions for Ga <sub>2</sub> O <sub>3</sub> Power Device Applications Open
This study investigates the effects of nitrogen doping on the structural, optical, and electrical properties of Cu 2 O and N‐doped Cu 2 O films deposited by RF magnetron sputtering using Cu or Cu 2 O targets under varying nitrogen flow con…
View article: Blue organic long-persistent luminescence via upconversion from charge-transfer to locally excited singlet state
Blue organic long-persistent luminescence via upconversion from charge-transfer to locally excited singlet state Open
View article: Instantaneous deposition-rate modulator for vacuum vapor deposition: fabrication of polarization gradated organic film
Instantaneous deposition-rate modulator for vacuum vapor deposition: fabrication of polarization gradated organic film Open
The molecular orientation and properties of vapor-deposited organic films are essential for device performance and typically governed by the deposition rate. Controlling the orientation during film growth allows the optimization of local p…
View article: Protein Electronic Energy Transport Levels Derived from High-Sensitivity Near-UV and Constant Final State Yield Photoemission Spectroscopy
Protein Electronic Energy Transport Levels Derived from High-Sensitivity Near-UV and Constant Final State Yield Photoemission Spectroscopy Open
Proteins are attractive as functional components in molecular junctions. However, control-ling the electronic charge transport via proteins, held between two electrodes, requires in-formation on their frontier orbital energy level alignmen…
View article: A class of chemical compounds enhances clustering of muscle nicotinic acetylcholine receptor in cultured myogenic cells
A class of chemical compounds enhances clustering of muscle nicotinic acetylcholine receptor in cultured myogenic cells Open
Neuromuscular signal transmission is affected in various diseases including myasthenia gravis, congenital myasthenic syndromes, and sarcopenia. We used an ATF2-luciferase system to monitor the phosphorylation of MuSK in HEK293 cells introd…
View article: The Electronic Structure and Tunneling Process of Carbon Nanotubes Observed Using High-sensitivity Ultraviolet Photoelectron Spectroscopy and Field Emission Spectroscopy
The Electronic Structure and Tunneling Process of Carbon Nanotubes Observed Using High-sensitivity Ultraviolet Photoelectron Spectroscopy and Field Emission Spectroscopy Open
The electronic structure and field emission characteristics of spray-coated single-walled carbon nanotubes (sprayed-SWCNTs) and vertically aligned multiwalled carbon nanotubes (VA-MWCNTs) were evaluated to discuss the feasibility of applyi…
View article: Reliable measurement of the density of states including occupied in-gap states of an amorphous In–Ga–Zn–O thin film via photoemission spectroscopies: Direct observation of light-induced in-gap states
Reliable measurement of the density of states including occupied in-gap states of an amorphous In–Ga–Zn–O thin film via photoemission spectroscopies: Direct observation of light-induced in-gap states Open
Illumination stress (IS) and negative bias under illumination stress (NBIS) cause considerable device instability in thin-film transistors based on amorphous In–Ga–Zn–O (a-IGZO). Models using in-gap states are suggested to explain device i…
View article: Blue organic long-persistent luminescence via upconversion from charge-transfer to locally excited singlet state
Blue organic long-persistent luminescence via upconversion from charge-transfer to locally excited singlet state Open
Long-persistent luminescence (LPL) materials have applications from safety signage to bioimaging; however, existing organic LPL (OLPL) systems do not align with human scotopic vision, which is sensitive to blue light. We reveal a ground-br…
View article: Blue organic long-persistent luminescence via upconversion from charge-transfer to locally excited singlet state
Blue organic long-persistent luminescence via upconversion from charge-transfer to locally excited singlet state Open
Long-persistent luminescence (LPL) materials have applications from safety signage to bioimaging; however, existing organic LPL (OLPL) systems do not align with human scotopic vision, which is sensitive to blue light. We reveal a ground-br…
View article: Impact of Intermittent Deposition on Spontaneous Orientation Polarization of Organic Amorphous Films Revealed by Rotary Kelvin Probe
Impact of Intermittent Deposition on Spontaneous Orientation Polarization of Organic Amorphous Films Revealed by Rotary Kelvin Probe Open
The control of the molecular orientation and resultant polarization is essential for improving the performance of organic optoelectronic devices. Conventionally, the substrate temperature and deposition rate are tuned to control the molecu…
View article: Observation of Surface Potential of Micropatterned Self-assembled Electrets for MEMS Vibrational Energy Harvesters
Observation of Surface Potential of Micropatterned Self-assembled Electrets for MEMS Vibrational Energy Harvesters Open
In this paper, we present the observation results of the surface potential of micropatterned thick (> 1 μm) self-assembled electrets (SAEs) for MEMS vibrational energy harvesters (VEHs).To evaluate the surface potential of micropatterned S…
View article: Stabilization of Spontaneous Orientation Polarization by Preventing Charge Injection from Electrodes
Stabilization of Spontaneous Orientation Polarization by Preventing Charge Injection from Electrodes Open
The stability of the surface potential derived from spontaneous orientation polarization (SOP) in 2,2′,2″-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) films was significantly improved by inserting an insulating layer at the…
View article: Understanding spontaneous orientation polarization of amorphous organic semiconducting films and its application to devices
Understanding spontaneous orientation polarization of amorphous organic semiconducting films and its application to devices Open
Spontaneous orientation polarization (SOP) of amorphous organic semiconducting films has attracted much attention because of its frequent observation in common organic light-emitting diodes (OLEDs) and potential influences on the device pr…
View article: Current Generation Mechanism in Self-assembled Electret-based Vibrational Energy Generators
Current Generation Mechanism in Self-assembled Electret-based Vibrational Energy Generators Open
Electret-based vibrational energy generators (E-VEGs) have attracted considerable attention because they can generate electrical power from ambient vibration.E-VEGs have a capacitor structure in which an electret and air gap are sandwiched…
View article: In-gap states of an amorphous In–Ga–Zn–O thin film studied via high-sensitivity ultraviolet photoemission spectroscopy using low-energy photons
In-gap states of an amorphous In–Ga–Zn–O thin film studied via high-sensitivity ultraviolet photoemission spectroscopy using low-energy photons Open
Low-density electronic states in the energy gap of an amorphous In–Ga–Zn–O film control device performance. Herein, density of states (DOS) distribution from valence band to the in-gap states of 1014 cm−3 eV−1 level was determined using hi…
View article: Direct Probing of Gap States and Their Passivation in Halide Perovskites by High-Sensitivity, Variable Energy Ultraviolet Photoelectron Spectroscopy
Direct Probing of Gap States and Their Passivation in Halide Perovskites by High-Sensitivity, Variable Energy Ultraviolet Photoelectron Spectroscopy Open
Direct detection of intrinsic defects in halide perovskites (HaPs) by standard methods utilizing optical excitation is quite challenging, due to the low density of defects in most samples of this family of materials (≤10^{15} cm^{–3} in po…
View article: Electret-Based Vibrational Energy Generator without Any Charging Process: Utilization of Spontaneous Orientation of Polar Organic Molecules
Electret-Based Vibrational Energy Generator without Any Charging Process: Utilization of Spontaneous Orientation of Polar Organic Molecules Open
Electret-based vibrational energy generators (E-VEGs) have attracted much attention because they can generate electrical power from ambient vibration. The electret is a key material for the E-VEG because the output power of the device is p…
View article: Coherent Electron Transport across a 3 nm Bioelectronic Junction Made of Multi-Heme Proteins
Coherent Electron Transport across a 3 nm Bioelectronic Junction Made of Multi-Heme Proteins Open
Multi-heme cytochromes (MHCs) are fascinating proteins used by bacterial organisms to shuttle electrons within, between, and out of their cells. When placed in solid-state electronic junctions, MHCs support temperature-independent currents…
View article: Off-resonant coherent electron transport over three nanometers in multi-heme protein bioelectronic junctions
Off-resonant coherent electron transport over three nanometers in multi-heme protein bioelectronic junctions Open
Multi-heme cytochromes (MHC) are fascinating proteins used by bacterial organisms to shuttle electrons within and between their cells. When placed in a solid state electronic junction, they support temperature-independent currents over sev…
View article: Self-Assembled Electret for Vibration-Based Power Generator
Self-Assembled Electret for Vibration-Based Power Generator Open
The vibration-based electret generators (EGs) for energy harvesting have been extensively studied because they can obtain electrical energy from ambient vibrations. EGs exhibit a sandwich structure of electrodes surrounding an air gap and …
View article: Crystalline versus Amorphous Donor-Acceptor Blends: Influence of Layer Morphology on the Charge-Transfer Density of States
Crystalline versus Amorphous Donor-Acceptor Blends: Influence of Layer Morphology on the Charge-Transfer Density of States Open
Organic small molecule solar cells are used as a test bed to investigate the influence of film morphology on the density of charge-transfer (CT) states. CT states are considered as precursors for charge generation and their energy as the u…
View article: Dipolar Doping of Organic Semiconductors to Enhance Carrier Injection
Dipolar Doping of Organic Semiconductors to Enhance Carrier Injection Open
If not oriented perfectly isotropically, the strong dipole moment of polar organic semiconductor materials such as tris-(8-hydroxyquinolate)aluminum (Alq3) will lead to the buildup of a giant surface potential (GSP) and thus to a macroscop…
View article: Demonstration of an electret generator for energy harvesting without any charging process: Utilization of spontaneous orientation of polar molecules
Demonstration of an electret generator for energy harvesting without any charging process: Utilization of spontaneous orientation of polar molecules Open
Vibration-driven electret generators (EGs) for energy harvesting have been intensively studied since they are expected to be used as electric source, especially, for low power consumption devices. EGs have generally capacitor structure con…
View article: Demonstration of an electret generator using self-assembled electret for energy harvesting without any charging process
Demonstration of an electret generator using self-assembled electret for energy harvesting without any charging process Open
Electret generators (EGs) for energy harvesting is a device which ambient vibrations convert into electric energy. They are expected as power supplies for low energy applications such as wireless sensors. In EGs, charges are induced by an …
View article: Muscle spindle reinnervation using transplanted embryonic dorsal root ganglion cells after peripheral nerve transection in rats
Muscle spindle reinnervation using transplanted embryonic dorsal root ganglion cells after peripheral nerve transection in rats Open
Objectives Muscle spindles are proprioceptive receptors in the skeletal muscle. Peripheral nerve injury results in a decreased number of muscle spindles and their morphologic deterioration. However, the muscle spindles recover when skeleta…
View article: Spontaneous orientation polarization in organic light-emitting diodes
Spontaneous orientation polarization in organic light-emitting diodes Open
Spontaneous orientation polarization (SOP) is inherent in the evaporated films of many organic semiconducting molecules with a permanent dipole moment. A significant electric field is formed in the film due to SOP. Consequently, the proper…
View article: Negative capacitance in an organic solar cell observed by displacement current measurement
Negative capacitance in an organic solar cell observed by displacement current measurement Open
We applied displacement current measurement (DCM) to an organic solar cell (OSC) with a structure of ITO/CuPc/C60/BCP/Al in order to investigate the origin of a negative capacitance (NC). In DCM curve, an anomalous characteristic that the …