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result(s) for
"Matsui, Hiroyuki"
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Fully Printed PEDOT:PSS-based Temperature Sensor with High Humidity Stability for Wireless Healthcare Monitoring
by
Wang, Yi-Fei
,
Kumaki, Daisuke
,
Tokito, Shizuo
in
639/301/1005/1007
,
639/301/1005/1009
,
Fabrication
2020
Facile fabrication and high ambient stability are strongly desired for the practical application of temperautre sensor in real-time wearable healthcare. Herein, a fully printed flexible temperature sensor based on cross-linked poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) was developed. By introducing the crosslinker of (3-glycidyloxypropyl)trimethoxysilane (GOPS) and the fluorinated polymer passivation (CYTOP), significant enhancements in humidity stability and temperature sensitivity of PEDOT:PSS based film were achieved. The prepared sensor exhibited excellent stability in environmental humidity ranged from 30% RH to 80% RH, and high sensitivity of −0.77% °C
−1
for temperature sensing between 25 °C and 50 °C. Moreover, a wireless temperature sensing platform was obtained by integrating the printed sensor to a printed flexible hybrid circuit, which performed a stable real-time healthcare monitoring.
Journal Article
Inkjet printing of single-crystal films
by
Minemawari, Hiromi
,
Yamada, Toshikazu
,
Kumai, Reiji
in
639/301/1005/1007
,
639/301/119/1000
,
Analysis
2011
Thin-film transistors in print
Printing electronic devices using semiconducting 'ink' is seen as a promising route to cheap, large-area and flexible electronics, but the performance of such devices suffers from the relatively poor crystallinity of the printed material. Hiromi Minemawari and colleagues have developed an inkjet-based printing technique involving controlled mixing on a surface of two solutions — the semiconductor (C8-BTBT) in its solvent and a liquid in which the semiconductor is insoluble. The products of this antisolvent crystallization technique are thin semiconductor films with exceptionally high and uniform crystallinity.
The use of single crystals has been fundamental to the development of semiconductor microelectronics and solid-state science
1
. Whether based on inorganic
2
,
3
,
4
,
5
or organic
6
,
7
,
8
materials, the devices that show the highest performance rely on single-crystal interfaces, with their nearly perfect translational symmetry and exceptionally high chemical purity. Attention has recently been focused on developing simple ways of producing electronic devices by means of printing technologies. ‘Printed electronics’ is being explored for the manufacture of large-area and flexible electronic devices by the patterned application of functional inks containing soluble or dispersed semiconducting materials
9
,
10
,
11
. However, because of the strong self-organizing tendency of the deposited materials
12
,
13
, the production of semiconducting thin films of high crystallinity (indispensable for realizing high carrier mobility) may be incompatible with conventional printing processes. Here we develop a method that combines the technique of antisolvent crystallization
14
with inkjet printing to produce organic semiconducting thin films of high crystallinity. Specifically, we show that mixing fine droplets of an antisolvent and a solution of an active semiconducting component within a confined area on an amorphous substrate can trigger the controlled formation of exceptionally uniform single-crystal or polycrystalline thin films that grow at the liquid–air interfaces. Using this approach, we have printed single crystals of the organic semiconductor 2,7-dioctyl[1]benzothieno[3,2-
b
][1]benzothiophene (C
8
-BTBT) (ref.
15
), yielding thin-film transistors with average carrier mobilities as high as 16.4 cm
2
V
−1
s
−1
. This printing technique constitutes a major step towards the use of high-performance single-crystal semiconductor devices for large-area and flexible electronics applications.
Journal Article
Noninvasive Sweat-Lactate Biosensor Emplsoying a Hydrogel-Based Touch Pad
2019
This study is the first report demonstrating proof-of-concept for a hydrogel-based touch sensor pad used for the non-invasive extraction and detection of sweat components. The sensor device was composed of an electrochemical L-lactate biosensor covered with an agarose gel in a phosphate buffer saline. When human skin contacts the agarose gel, L-lactate in sweat was continuously extracted into the gel, followed by
in-situ
potentiometric detection without controlled conditions. This novel type of sweat sensor is expected to enable the simple, non-invasive daily periodic monitoring of sweat biomarkers for advanced personal healthcare methods in the future.
Journal Article
Alternative net longwave radiation equation for the FAO Penman–Monteith evapotranspiration equation and the Penman evaporation equation
2023
Net longwave radiation, which is an essential factor in evapotranspiration, is generally estimated by multiplying the net emissivity under clear-sky conditions by the effect of cloudiness. In this study, we proposed a phenomenon-specific daily net longwave radiation function, in the form of a difference between the upward longwave radiation and the downward longwave radiation, for the Penman–Monteith evapotranspiration equation and the Penman evaporation equation. In addition, we verified the net longwave radiation equation by comparing the observed downward longwave radiation with that estimated by the downward longwave radiation equation derived from the well-known net longwave radiation equations in the Penman–Monteith evapotranspiration equation and the Penman evaporation equation. The downward longwave radiation equation constituting the proposed net longwave radiation equation w1ith four calibrated parameters had an RMSE of 8.60 W m−2 and MBE of − 4.37 W m−2 and is more accurate than the downward longwave radiation equations derived from the general net longwave radiation equations at Tateno, Japan.
Journal Article
Coexistence of ultra-long spin relaxation time and coherent charge transport in organic single-crystal semiconductors
by
Häusermann, Roger
,
Takeya, Jun
,
Tsurumi, Junto
in
639/301/1005/1007
,
639/766/119/1000
,
639/766/119/1001
2017
Coherent charge transport can occur in organic semiconductor crystals thanks to the highly periodic electrostatic potential—despite the weak van der Waals bonds. And as spin–orbit coupling is usually weak in organic materials, robust spin transport is expected, which is essential if they are to be exploited for spintronic applications. In such systems, momentum relaxation occurs via scattering events, which enables an intrinsic mobility to be defined for band-like charge transport, which is >10 cm
2
V
−1
s
−1
. In contrast, there are relatively few experimental studies of the intrinsic spin relaxation for organic band-transport systems. Here, we demonstrate that the intrinsic spin relaxation in organic semiconductors is also caused by scattering events, with much less frequency than the momentum relaxation. Magnetotransport measurements and electron spin resonance spectroscopy consistently show a linear relationship between the two relaxation times over a wide temperature range, clearly manifesting the Elliott–Yafet type of spin relaxation mechanism. The coexistence of an ultra-long spin lifetime of milliseconds and the coherent band-like transport, resulting in a micrometre-scale spin diffusion length, constitutes a key step towards realizing spintronic devices based on organic single crystals.
A linear relationship between spin and momentum relaxation shows that the spin relaxation in an organic semiconductor crystal that has ultra-long spin lifetimes and coherent band-like transport is governed by the Elliott–Yafet mechanism.
Journal Article
Statistical analysis of interatomic transfer integrals for exploring high-mobility organic semiconductors
by
Okada, Tomoharu
,
Matsui, Hiroyuki
,
Ozawa, Koki
in
Aromatic compounds
,
Charge transport
,
Crystal structure
2024
Charge transport in organic semiconductors occurs via overlapping molecular orbitals quantified by transfer integrals. However, no statistical study of transfer integrals for a wide variety of molecules has been reported. Here we present a statistical analysis of transfer integrals for more than 27,000 organic compounds in the Cambridge Structural Database. Interatomic transfer integrals were used to identify substructures with high transfer integrals. As a result, thione and amine groups as in thiourea were found to exhibit high transfer integrals. Such compounds are considered as potential non-aromatic, water-soluble organic semiconductors.
Journal Article
Fully Printed Wearable Vital Sensor for Human Pulse Rate Monitoring using Ferroelectric Polymer
by
Kumaki, Daisuke
,
Domingues Dos Santos, Fabrice
,
Sugano, Ryo
in
639/166/987
,
639/301/1005/1009
,
Cardiovascular diseases
2018
The ability to monitor subtle changes in vital and arterial signals using flexible devices attached to the human skin can be valuable for the detection of various health conditions such as cardiovascular disease. Conventional Si device technologies are being utilised in traditional clinical systems; however, its fabrication is not easy owing to the difficulties in adapting to conventional processes. Here, we present the development of a fully printed, wearable, ferroelectric-polymer vital sensor for monitoring the human pulse wave/rate on the skin. This vital sensor is compact, thin, sufficiently flexible, and conforms to the skin while providing high pressure sensitivity, fast response time, superior operational stability, and excellent mechanical fatigue properties. Moreover, the vital sensor is connected to a communication amplifier circuit for monitoring the pulse waves with a wireless sensing system. This sensor system can realise the development of new healthcare devices for wearable sensor applications.
Journal Article
Suppressing molecular vibrations in organic semiconductors by inducing strain
by
Häusermann, Roger
,
Yamashita, Yu
,
Takeya, Jun
in
639/301/119/1000
,
639/301/119/998
,
639/301/923/3931
2016
Organic molecular semiconductors are solution processable, enabling the growth of large-area single-crystal semiconductors. Improving the performance of organic semiconductor devices by increasing the charge mobility is an ongoing quest, which calls for novel molecular and material design, and improved processing conditions. Here we show a method to increase the charge mobility in organic single-crystal field-effect transistors, by taking advantage of the inherent softness of organic semiconductors. We compress the crystal lattice uniaxially by bending the flexible devices, leading to an improved charge transport. The mobility increases from 9.7 to 16.5 cm
2
V
−1
s
−1
by 70% under 3% strain. In-depth analysis indicates that compressing the crystal structure directly restricts the vibration of the molecules, thus suppresses dynamic disorder, a unique mechanism in organic semiconductors. Since strain can be easily induced during the fabrication process, we expect our method to be exploited to build high-performance organic devices.
The mobility of organic semiconductors can be tuned by modifying their chemical composition or crystalline properties. Here, the authors show that bending organic single crystals increases their field effect transistor mobility due to restrained molecular vibrations and subsequently reduced dynamic disorder.
Journal Article
Extremely rapid self-reaction of the simplest Criegee intermediate CH2OO and its implications in atmospheric chemistry
2014
Criegee intermediates, which are carbonyl oxides produced when ozone reacts with unsaturated hydrocarbons, play an important role in the formation of OH and organic acids in the atmosphere, but they have eluded direct detection until recently. Reactions that involve Criegee intermediates are not understood fully because data based on their direct observation are limited. We used transient infrared absorption spectroscopy to probe directly the decay kinetics of formaldehyde oxide (CH
2
OO) and found that it reacts with itself extremely rapidly. This fast self-reaction is a result of its zwitterionic character. According to our quantum-chemical calculations, a cyclic dimeric intermediate that has the terminal O atom of one CH
2
OO bonded to the C atom of the other CH
2
OO is formed with large exothermicity before further decomposition to 2H
2
CO + O
2
(
1
Δ
g
). We suggest that the inclusion of this previously overlooked rapid reaction in models may affect the interpretation of previous laboratory experiments that involve Criegee intermediates.
Criegee intermediates play an important role in atmospheric chemistry but their direct study has proved difficult. Transient infrared absorption spectroscopy has now been used to probe the decay kinetics of the Criegee intermediate CH
2
OO directly, revealing that its self-reaction is extremely rapid. This may have important consequences for the interpretation of previous laboratory experiments.
Journal Article
ILF2 enhances the DNA cytosine deaminase activity of tumor mutator APOBEC3B in multiple myeloma cells
2022
DNA cytosine deaminase APOBEC3B (A3B) is an endogenous source of mutations in many human cancers, including multiple myeloma. A3B proteins form catalytically inactive high molecular mass (HMM) complexes in nuclei, however, the regulatory mechanisms of A3B deaminase activity in HMM complexes are still unclear. Here, we performed mass spectrometry analysis of A3B-interacting proteins from nuclear extracts of myeloma cell lines and identified 30 putative interacting proteins. These proteins are involved in RNA metabolism, including RNA binding, mRNA splicing, translation, and regulation of gene expression. Except for SAFB, these proteins interact with A3B in an RNA-dependent manner. Most of these interacting proteins are detected in A3B HMM complexes by density gradient sedimentation assays. We focused on two interacting proteins, ILF2 and SAFB. We found that overexpressed ILF2 enhanced the deaminase activity of A3B by 30%, while SAFB did not. Additionally, siRNA-mediated knockdown of ILF2 suppressed A3B deaminase activity by 30% in HEK293T cell lysates. Based on these findings, we conclude that ILF2 can interact with A3B and enhance its deaminase activity in HMM complexes.
Journal Article