| 1. |
Takeshi Shinkai, Jonas Karl Christopher N. Agutaya, Biplab Manna, Matthias Boepple, Masaru Iwai, Keigo Masumoto, Kanako Koga, Koki Kawanami, Yusui Nakamura, Armando T. Quitain, Koichi Suematsu, Yusuke Inomata, Nicolae Barsan, Tetsuya Kida, Ethanol sensing mechanism of ZnO nanorods revealed by DRIFT spectroscopy and DFT calculations, Journal of Materials Chemistry A, 10.1039/d3ta06486g, 2024.02. |
| 2. |
Hirotaka Koga, Kazuki Nagashima, Koichi Suematsu, Tsunaki Takahashi, Luting Zhu, Daiki Fukushima, Yintong Huang, Ryo Nakagawa, Jiangyang Liu, Kojiro Uetani, Masaya Nogi, Takeshi Yanagida, Yuta Nishina, Nanocellulose Paper Semiconductor with a Three-Dimensional Network Structure and Its Nano–Micro–Macro Trans-Scale Design, ACS Nano, 2022.03, Semiconducting nanomaterials with 3D network structures exhibit various fascinating properties such as electrical conduction, high permeability, and large surface areas, which are beneficial for adsorption, separation, and sensing applications. However, research on these materials is substantially restricted by the limited trans-scalability of their structural design and tunability of electrical conductivity. To overcome this challenge, a pyrolyzed cellulose nanofiber paper (CNP) semiconductor with a 3D network structure is proposed. Its nano–micro–macro trans-scale structural design is achieved by a combination of iodine-mediated morphology-retaining pyrolysis with spatially controlled drying of a cellulose nanofiber dispersion and paper-crafting techniques, such as microembossing, origami, and kirigami. The electrical conduction of this semiconductor is widely and systematically tuned, via the temperature-controlled progressive pyrolysis of CNP, from insulating (1012 Ω cm) to quasimetallic (10–2 Ω cm), which considerably exceeds that attained in other previously reported nanomaterials with 3D networks. The pyrolyzed CNP semiconductor provides not only the tailorable functionality for applications ranging from water-vapor-selective sensors to enzymatic biofuel cell electrodes but also the designability of macroscopic device configurations for stretchable and wearable applications. This study provides a pathway to realize structurally and functionally designable semiconducting nanomaterials and all-nanocellulose semiconducting technology for diverse electronics.. |
| 3. |
Ken Watanabe, Ayumu Tashiro, Yoshihiro Ichinose, Shinichi Takeno, Koichi Suematsu, Kazutaka Mitsuishic, Kengo Shimanoea, Lowering the sintering temperature of Li7La3Zr2O12 electrolyte for co-fired all-solid-state battery by Bi-substitution and precise control of compositional deviation, Journal of the Ceramic Society of Japan, 2022.02. |
| 4. |
Yongjiao Sun, Zhenting Zhao, Koichi Suematsu, Zhang Wenlei, Serge Zhuikyov, Jie Hu, Kengo Shimanoe, MOF-derived Au-NiO/In2O3 for selective and fast detection of toluene at ppb-level in high humid environments, Sensors and Actuator B Chemical, 360, 131631, 2022.02. |
| 5. |
Koichi Suematsu, Yuki Hiroyama, Ken Watanabe, Kengo Shimanoe, Amplifying the Receptor Function on Ba0.9La0.1FeO3-SnO2 Composite Particle Surface for High Sensitivity Toward Ethanol Gas Sensing, Sensors and Actuator B Chemical, 10.1016/j.snb.2021.131256, 354, 131256, 2021.12, Composite particles of Ba0.9La0.1FeO3 (BLF) and SnO2 have been designed to amplify the receptor function of semiconductor gas sensor and achieve high sensitivity toward volatile organic compound gases. During operation, the sensor was driven under double-pulse mode (DP-mode) that includes high-temperature preheating. According to the temperature programmed desorption measurement, oxygen desorption from the BLF-SnO2 composite occurred at lower temperatures than that from SnO2, and the amount of oxygen desorption was also larger. Under the DP-mode, the electrical resistance of BLF-SnO2 was significantly higher than that of SnO2, because BLF acted as an oxygen supplier to increase effective oxygen concentration in the sensing layer. In addition, temperature programmed reaction measurement revealed that ethanol desorbed from BLF, and that the total amount of ethanol desorption and combustion on BLF-SnO2 was larger than that on SnO2. Thus, the sensor response to ethanol based on ethanol combustion reaction was enhanced when using BLF-SnO2 under the DP-mode, especially the sensor response to 1 ppm ethanol showed 143 at the preheating and measurement temperatures of 400 °C and 250 °C, respectively. This enhanced response was attributed to the condensation of oxygen and ethanol under the DP-mode, with BLF playing the role of oxygen and ethanol provider. Thus, compositing BLF with SnO2 significantly amplified the receptor function of the sensing material, and such materials design could lead to improved sensitivity.. |
| 6. |
Yongjiao Sun, Zhenting Zhao, Koichi Suematsu, Pengwei Li, Wendong Zhang, Jie Hu, Moisture-resisting acetone sensor based on MOF-derived ZnO-NiO nanocomposites, Materials Research Bulletin, 10.1016/j.materresbull.2021.111607, 2021.10. |
| 7. |
Yongjiao Sun, Zhenting Zhao, Rui Zhou, Pengwei Li, Wendong Zhang, Koichi Suematsu, Jie Hu, Synthesis of In2O3 nanocubes, nanocube clusters, and nanocubes-embedded Au nanoparticles for conductometric CO sensors, Sensors and Actuator B Chemical, 2021.07. |
| 8. |
Shingo IDE, Ken WATANABE, Koichi SUEMATSU, Yasuhiro SETO, Isamu YASHIMA, Kengo SHIMANOE, DC-Voltage-Induced High Oxygen Permeation through a Lanthanum Silicate Electrolyte with a Cerium Oxide Thin Film, Electrochemistry, 2021.05. |
| 9. |
Chengcheng Liu, Koichi Suematsu, Akihito Uchiyama, Ken Watanabe, Yanbao Guo, Deguo Wang, Kengo Shimanoe, Impact of Pd Nanoparticles Loading Method on SnO2 Surface for Natural Gas Detection in Humid Atmosphere, Journal of Materials Science, 2021.05. |
| 10. |
Ryunosuke Okuda, Koichi Suematsu, Ken Watanabe, Kengo Shimanoe , Highly Porous Chitosan-derived Nitrogen Doped Carbon Applicable for High-performance Gas Diffusion Type Oxygen Electrode, Chemistry Letters, 10.1246/cl.200748, 2021.01. |
| 11. |
Koichi Suematsu, Wataru Harano, Shigeto Yamasaki, Ken Watanabe, Kengo Shimanoe , One-Trillionth Level Toluene Detection Using Dual-Designed Semiconductor Gas Sensor: Materials and Sensor Driven Designs, ACS Applied Electronic Materials, 10.1021/acsaelm.0c00902, 2020.12, Lowering the volatile organic compound (VOC) gas detection limit toward the ppt level on a resistive-type semiconductor gas sensor was achieved by combining the material and sensor-driven designs. We fabricated Pd-SnO2 clustered nanoparticles, a material that is highly sensitive to VOC gas, on a microsensor device with a double-pulse-driven mode. This mode was involved in switching the heater-on periods at high-temperature preheating and measurement phases and the rest phase during a heater-off period between preheating and measurement phases. The electrical resistance in synthetic air and the sensor response to toluene increased as preheating temperatures increased because of an increase in the amount of O2– adsorbed on the particle surface. In addition, extending the rest time between the preheating and measurement phases significantly improved the sensor response to toluene. According to the relationship between the sensor response and toluene concentration, we improved the lower detection limit for toluene gas to below 10 ppt, with preheating and measurement temperatures at 400 and 250 °C, respectively, and rest time at 100 s. Therefore, the combination of the material and sensor-driven designs may play a key role in improving the sensor performance.. |
| 12. |
Ryunosuke Okuda, Kota Nakano, Koichi Suematsu, Ken Watanabe, Anna Ilnicka, Jerzy P Łukaszewicz, Kengo Shimanoe, Chemical Activation of Nitrogen-doped Carbon Derived from Chitosan with ZnCl2 to Produce a High-performance Gas Diffusion-type Oxygen Electrode, Electrochemistry, 10.5796/electrochemistry.20-00121, 2020.10. |
| 13. |
Shingo Ide, Ken Watanabe, Koichi Suematsu, IsamuYashima, Kengo Shimanoe , Crystal Growth Mechanism of Highly c-Axis-Oriented Apatite-Type Lanthanum Borosilicate using B2O3 Vapor, ACS Omega, 2020.10. |
| 14. |
Koichi Suematsu, Tokiharu Oyama, Wataru Mizukami, Yuki HIroyama, Ken Watanabe, Kengo Shimanoe, Selective Detection of Toluene Using Pulse-Driven SnO2 Micro Gas Sensors, ACS Applied Electronic Materials, 2, 2913-2920, 2020.08, Improvement of gas selectivity, especially among volatile organic compound (VOC) gases, was attempted by introducing pulse-driven modes in semiconductor gas sensors. The SnO2 microsensor was fabricated on a miniature sensor device constructed with a microheater and electrode. The gas-sensing properties were evaluated under a pulse-driven mode by switching the heater on and off. According to density functional theory calculations and temperature-programmed reaction measurements, toluene molecule, which is one of the VOC gases, was adsorbed on the SnO2 surface by van der Waals forces. The conventional sensor response, Se, defined as the change in the electrical resistance in air and target gas atmosphere, to toluene was four and eight times greater than that to CO and H2, respectively. Moreover, the newly proposed sensor response, Sp, defined as the change in the electrical resistance of the device in the target gas atmosphere during the heater-on period, to toluene was 33 and 29 times greater than that to CO and H2, respectively. This significant difference in the Sp to toluene was caused by the combustion reaction of condensed toluene within the sensing layer. Accordingly, the pulse-driven mode of the semiconductor gas sensor can be exploited to improve the gas selectivity of VOC gases based on these newly defined sensor response measures.. |
| 15. |
Yongjiao Sun, Haoyue Yang, Zhenting Zhao, Koichi Suematsu, Pengwei Li, Zhichao Yu, Wendong Zhang, Jie Hu, Fabrication of ZnO quantum dots@SnO2 hollow nanospheres hybrid hierarchical structures for effectively detecting formaldehyde., Sensors and Actuator B, 10.1016/j.snb.2020.128222, 2020.05. |
| 16. |
Nan Ma, Shingo Ide, Koichi Suematsu, Ken Watanabe, Kengo Shimanoe, Novel Solid Electrolyte CO2 Gas Sensors Based on c-Axis-Oriented Y-doped La9.66Si5.3B0.7O26.14, ACS Applied Materials and Interfaces, 10.1021/acsami.0c00454, 2020.04. |
| 17. |
Yongjiao Sun, Zhenting Zhao, Koichi Suematsu, Pengwei Li, Zhichao Yu, Wendong Zhang, Jie Hu, Kengo Shimanoe, Rapid and Stable Detection of Carbon Monoxide in Changing Humidity Atmospheres Using Clustered In2O3/CuO Nanospheres, ACS sensors, 10.1021/acssensors.9b02557, 5, 4, 1040-1049, 2020.04, Clustered indium oxide/copper oxide (In2O3/CuO) nanospheres with different CuO amounts were successfully synthesized as sensing materials for the carbon monoxide (CO) detection. Component and morphological characterizations were performed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Sensing performance for CO of the clustered In2O3 and In2O3/CuO nanospheres were investigated under different temperatures and humidity conditions. The results show that the sensors based on 2 mol % In2O3/CuO (InCu2) exhibit about threefold improvement in response to CO compared to that of In2O3 with quick response and recovery time, wide linearity, and low detection limit at 200 °C under 25% relative humidity (RH). Moreover, it shows tiny resistance and response declines despite the wide range of humidity variation from 25 to 95% RH. Meanwhile, the mechanism of enhanced gas-sensing performances and antihumidity properties of InCu2 were systematically investigated. We speculated that most of the water-driven species are predominantly adsorbed by CuO due to its high affinity to the hydroxyl group, which suppresses the interaction between moisture and In2O3. InCu2 is a new and promising material to sense CO in a highly sensitive and fast manner with negligible interference from ambient humidity.. |
| 18. |
Shingo Ide, Hiroki Takahashi, Isamu Yashima, Koichi Suematsu, Ken Watanabe, Kengo Shimanoe, Effect of Boron Substitution on Oxide-Ion Conduction in c-Axis-Oriented Apatite-Type Lanthanum Silicate, Journal of Physical Chemistry C, 10.1021/acs.jpcc.9b11454, 124, 5, 2879-2885, 2020.02, Apatite-type lanthanum silicate (LSO) is a material with high oxide-ion conductivity in the low- and intermediateerature range (573-873 K) and is, therefore, a promising solid electrolyte for lowerature applications such as solid oxide fuel cells and oxygen sensors. Herein, the effect of B substitution at the Si site in a c-axis-oriented apatite-type lanthanum silicate (La9.7Si5.3B0.7O26.2, c-LSBO) polycrystal on oxide-ion conduction is investigated. A highly c-axis-oriented LSBO polycrystal is fabricated by a vapor-solid reaction in which a dense La2SiO5 disk is heated in B2O3 vapor at ≥1673 K. The oxide-ion conductivity of c-LSBO reaches 16 mS cm-1 at 678 K with an activation energy of 0.4 eV. The obtained oxide-ion conductivity of c-LSBO is approximately 190 times higher than that of yttria-stabilized zirconia and 5.8 times higher than that of the polycrystalline c-axis-oriented nondoped lanthanum silicate. Based on 11B nuclear magnetic resonance measurements, B is located at the SiO4 site as BO4, suggesting the formation of an oxygen vacancy at the O4 site located along the c-axis due to charge compensation. In addition, molecular dynamics simulations indicate that the oxide-ion diffusion coefficient of the B-doped LSO is higher than that of the nondoped LSO. The high oxide-ion conductivity of c-LSBO is likely attributable to the formation of an oxygen vacancy at the O4 site by B doping, which has a lower valency than Si. Therefore, c-LSBO is a promising candidate as a solid electrolyte in electrochemical devices operating at low and moderately high temperatures.. |
| 19. |
Koichi Suematsu, Ken Watanabe, Masayoshi Yuasa, Tetsuya Kida, Kengo Shimanoe, Effect of Ambient Oxygen Partial Pressure on the Hydrogen Response of SnO2 Semiconductor Gas Sensors, Journal of the Electrochemical Society, 10.1149/2.1391906jes, 166, B618-B622, 2019.04, In this study, the influence of the oxygen partial pressures (PO2) on the sensor response to H2 of SnO2 resistive-type gas sensors was evaluated under various humid atmospheres. SnO2 nanoparticles of 8–15 nm in diameter were synthesized using a hydrothermal technique followed by calcination at 600°C. Additionally, a large amount of pores with diameters greater than 10 nm was confirmed in the nanoparticles. The electrical resistance at 350°C was decreased with decreasing the PO2, and the electrical resistance in the presence of 10 ppm H2 was much smaller than that in the absence of H2 in both dry and humid atmospheres regardless of the PO2. Furthermore, the sensor response to 10 ppm H2 at 350°C increased with decreasing PO2 in both dry and humid atmospheres. Thus, decreasing the amount of oxygen adsorption enhanced the effect of rooted hydroxyl formation on the SnO2 surface through a combustion reaction between H2 and adsorbed oxygen and improved the sensor response to H2. These results are important for understanding the fundamental mechanisms of gas detection and for the material surface design of highly sensitive resistive-type semiconductor gas sensors.. |
| 20. |
Ken Watanabe, Shingo Ide, Takashi Kumagai, Takaaki Fujino, Koichi Suematsu, Kengo Shimanoe, Oxygen pumping based on c-axis-oriented lanthanum silicate ceramics: Challenge toward low operating temperature, Journal of the Ceramics Society of Japan, 2018.11. |
| 21. |
Koichi Suematsu, Hotaka Uchino, Takaharu Mizukami, Ken Watanabe, Kengo Shimanoe, Oxygen adsorption on ZrO2 loaded SnO2 gas sensors in humid atmosphere, Journal of Materials Science, 2018.10. |
| 22. |
Koichi Suematsu, Wataru Harano, Tokiharu Oyama, Yuka Shin, Ken Watanabe, Kengo Shimanoe, Pulse-Driven Semiconductor Gas Sensors Toward ppt Level Toluene Detection, Analytical Chemistry, 2018.08, Improvements in the responses of semiconductor gas sensors and reductions in their detection limits toward volatile organic compounds (VOCs) are required in order to facilitate the simple detection of diseases, such as cancer, through human-breath analysis. In this study, we introduce a heater-switching, pulse-driven, micro gas sensor composed of a microheater and a sensor electrode fabricated with Pd-SnO2-clustered nanoparticles as the sensing material. The sensor was repeatedly heated and allowed to cool by the application of voltage to the microheater; the VOC gases penetrate into the interior of the sensing layer during its unheated state. Consequently, the utility factor of the pulse-driven sensor was greater than that of a conventional, continuously heated sensor. As a result, the response of the sensor to toluene was enhanced; indeed, the sensor responded to toluene at levels of 1 ppb. In addition, according to the relationship between its response and concentration of toluene, the pulse-driven sensor in this report can detect toluene at concentrations of 200 ppt and even lower. Therefore, the combination of a pulse-driven microheater and a suitable material designed to detect toluene resulted in improved sensor response, and facilitated ppt-level toluene detection. This sensor may play a key role in the development of medical diagnoses based on human breath.. |
| 23. |
Yongjiao Sun, Koichi Suematsu, Ken Watanabe, Maiko Nishibori, Jie Hu, Wendong Zhang, Kengo Shimanoe, Determination of effective oxygen adsorption species for CO sensing based on electric properties of indium oxide, Journal of the Electrochemical Society, 165, B275-B280, 2018.04. |
| 24. |
Koichi Suematsu, Masashi Arimura, Naoyuki Uchiyama, Shingo Saita, Transparent BaTiO3/PMMA Nanocomposite Films for Display Technologies: Facile Surface Modification Approach for BaTiO3 Nanoparticles, ACS Applied Nano Materials, 1, 2430-2437, 2018.04, Fabrication of a transparent film composed of a barium titanate (BaTiO3) and poly(methyl methacrylate) (PMMA) matrix is reported to expand the application field for composite films such as displays and touch panel screens. BaTiO3 nanoparticles are synthesized by sol–gel route with dispersion carried out in 2-methoxyethanol. The synthesized nanoparticles are 10 nm in size and are highly dispersed in the solvent. The surfaces of the obtained nanoparticles are modified by treatment with titanium isopropoxide and by using two silane coupling agents: n-decyltrimethoxysilane and 3-(triethoxysilyl)propyl methacrylate. The surface-modified BaTiO3 nanoparticles were then added to a sample of methyl methacrylate to obtain a transparent BaTiO3 dispersion. Transparent BaTiO3/PMMA nanocomposite films (sheet type, thickness of 150 μm) are obtained by the polymerization of the BaTiO3/MMA dispersion via heat treatment and by using a polymerization initiator. The visual transparency of the BaTiO3/PMMA film is comparable to that of the original PMMA film. Additionally, no difference in the transparency of the BaTiO3/PMMA films is observed when the BaTiO3 weight ratio is varied between 5% and 33%. The dielectric constant of the nanocomposite film improved from 4.6 (PMMA only) to 7.1 by incorporating 10 wt % of BaTiO3. Such improvement in the dielectric properties, while maintaining the transparency, flexibility, and workability of PMMA films, allows the expansion of the fields of functional ceramics and polymers.. |
| 25. |
Koichi Suematsu, Nan Ma, Ken Watanabe, Masayoshi Yuasa, Tetsuya Kida, Kengo Shimanoe, Effect of humid Aging on the Oxygen Adsorption in SnO2 Gas Sensors, Sensors, 18, 254, 2018.01. |
| 26. |
Koichi Suematsu, Kosuke Watanabe, Akihiro Tou, Yonjiao Sun, Kengo Shimanoe, Ultraselective Toluene Gas Sensor: Nanosized Gold Loaded on Zinc Oxide Nanoparticles, Analytical Chemistry, 90, 1959-1966, 2018.01, Selectivity is an important parameter of resistivetype gas sensors that use metal oxides. In this study, a highly selective toluene sensor is prepared using highly dispersed goldnanoparticle-loaded zinc oxide nanoparticles (Au-ZnO NPs). Au-ZnO NPs are synthesized by coprecipitation and calcination at 400 °C with Au loadings of 0.15, 0.5, and 1.5 mol %. The Au NPs on ZnO are about 2−4 nm in size, and exist in a metallic state. Porous gas-sensing layers are fabricated by screen printing. The responses of the sensor to 200 ppm hydrogen, 200 ppm carbon monoxide, 100 ppm ethanol, 100 ppm acetaldehyde, 100 ppm acetone, and 100 ppm toluene are evaluated at 377 °C in a dry atmosphere. The sensor response of 0.15 mol % Au-ZnO NPs to toluene is about 92, whereas its sensor responses to other combustible gases are less than 7. Such selective toluene detection is probably caused by the utilization efficiency of the gas-sensing layer. Gas diffusivity into the sensing layer of Au-ZnO NPs is lowered by the catalytic oxidation of combustible gases during their diffusion through the layer. The present approach is an effective way to improve the selectivity of resistive-type gas sensors.. |
| 27. |
Shunsuke Gunji, Masaya Jukei, Yasuhiko Shimotsuma, Kiyotaka Miura, Koichi Suematsu, Ken Watanabe, Kengo Shimanoe, Unexpected gas sensing properties of SiO2/SnO2 core–shell nanofibers under dry and humid conditions, Journal of Materials Chemistry C, 10.1039/c7tc01642e, 5, 6369-6376, 2017.06. |
| 28. |
Tetsuya Kida, Koichi Suematsu, Kazuyoshi Hara, Kiyoshi Kanie, Atsushi Muramatsu, Ultrasensitive Detection of Volatile Organic Compounds by a Pore Tuning Approach Using Anisotropically Shaped SnO2 Nanocrystal, ACS Applied Materials and Interfaces, 10.1021/acsami.6b13006, 8, 35485-35495, 2016.11. |
| 29. |
Koichi Suematsu, Kiyomi Yamada, Masayoshi Yuasa, Tetsuya Kida, Kengo Shimanoe, Evaluation of Oxygen Adsorption Based on the Electric Properties of SnO2 Semiconductor Gas Sensors, Sensors and Materials, 28, 1211-1217, 2016.08. |
| 30. |
Koichi Suematsu, Masashi Arimura, Naoyuki Uchiyama, Shingo Saita, Teruhisa Makino, Synthesis and Design of BaTiO3/Polymer Composite Ink to Improve the Dielectric Properties of Thin Films, Composites Part B: Engineering, 10.1016/j.compositesb.2016.08.011, 104, 80-86, 2016.08. |
| 31. |
Masayoshi Yuasa, Koichi Suematsu, Kiyomi Yamada, Ken Watanabe, Tetsuya Kida, Noboru Yamazoe, Kengo Shimanoe, Thermally stable SnO2 nanocrystals: Synthesis and application to gas sensors, Crystal Growth and Design, 10.1021/acs.cgd.6b00087, 16, 8, 4203-4208, 2016.08, © 2016 American Chemical Society. In this study, we prepared thermally stable SnO2 nanocrystals (ca. 4 nm) in a mixture of SnCl4, tetraethylene glycol (TEG), and tetrabutylammonium hydroxide (TBAH) under reflux and obtained a highly sensitive semiconductor gas sensor. It has been determined both theoretically and experimentally that the synthesis of oxide semiconductor nanoparticles is an important factor in highly sensitive semiconductor gas sensors. However, as-synthesized nanocrystals generally grow large during calcination at high temperature, and this thermal crystal growth reduces the sensor response. Therefore, to refine the response of the semiconductor gas sensor, we synthesized thermally stable SnO2 nanocrystals by heating under reflux a SnCl4-TBAH-TEG mixture. The obtained SnO2 nanocrystals exhibited high thermal stability even when calcined at a temperature up to 600 °C. The gas-sensing films fabricated from the thermally stable SnO2 nanocrystals exhibited a high sensor response to hydrogen due to their small crystal size, and a change in their surface property as compared with conventional SnO2 nanocrystals synthesized via hydrothermal treatment.. |
| 32. |
Koichi Suematsu, Miyuki Sasaki, Nan Ma, Masayoshi Yuasa, Kengo Shimanoe, Antimony-doped tin dioxide gas sensors exhibiting high stability of the sensitivity to humidity changes, ACS Sensors, 10.1021/acssensors.6b00323, 1, 913-920, 2016.06, The type and amounts of oxygen adsorption species at various atmospheric humidity levels are important factors in improving the sensitivity to combustible gases and stability to humidity changes of SnO2-based resistive-type gas sensors. We investigated the effect of antimony (Sb) doping of SnO2 nanoparticles on the stability of the sensitivity to humidity changes and oxygen adsorption species under humid atmosphere. No significant degradation of the sensitivity to hydrogen of Sb-SnO2 sensors was observed between 16 and 96 RH%, while an undoped SnO2 sensor showed gradually ecreasing responses with increasing humidity. An evaluation of oxygen adsorption species under humid atmosphere showed a transition from O2− to O− with increasing humidity from 16 to 96 RH%. However, the O2− adsorption sites were maintained on the surfaces of the Sb- SnO2, even as the humidity increased. Moreover, the extent of oxygen adsorption on the Sb-SnO2 was not obviously changed with increasing humidity. These results indicate that Sb atoms function as hydroxyl absorbers and also generate O2− adsorption sites in their vicinity. Additionally, Pd loading on the Sb-SnO2 further enhanced the sensor response under humid atmosphere, while maintaining the stability to humidity changes. Therefore, we successfully imparted stability to the sensitivity of SnO2 nanoparticles during humidity changes, representing an important improvement with applications to the development of high performance, practical, resistive-type gas sensors.. |
| 33. |
Koichi Suematsu, Nan Ma, Kazuya Kodama, Masayoshi Yuasa, tetsuya Kida, Kengo Shimanoe, Vanadium oxide loading on tin dioxide nanoparticles for improving gas detection in a humid atmosphere, Materials Letters, 10.1016/j.matlet.2016.05.083, 179, 214-216, 2016.05. |
| 34. |
Koichi Suematsu, Masashi Arimura, Naoyuki Uchiyama, Shingo Saita, Teruhisa Makino, High-performance dielectric thin film nanocomposites of barium titanate and cyanoethyl pullulan: controlling the barium titanate nanoparticle size using a sol-gel method, RSC Advances, 10.1039/C5RA27644F, 6, 20807-20813, 2016.02. |
| 35. |
Noboru Yamazoe, Koichi Suematsu, Kengo Shimanoe, Surface chemistry of neat tin oxide sensor for response to hydrogen gas in air, Sensors and Actuator B Chemical, 10.1016/j.snb.2015.12.064, 227, 403-410, 2015.12. |
| 36. |
Koichi Suematsu, Kazuya Kodama, Nan Ma, Masayoshi Yuasa, tetsuya Kida, Kengo Shimanoe, Role of vanadium oxide and palladium multiple loading on the sensitvity and recovery kinetics of tin dioxide based gas sensors, RSC Advances, 10.1039/C5RA20994C, 6, 5169-5176, 2015.12. |
| 37. |
Koichi Suematsu, Nan Ma, Masayoshi Yuasa, Tetsuya Kida, Kengo Shimanoe, Surface-modification of SnO2 nanoparticles by incorporation of Al for the detection of combustible gases in humid atmosphere, RSC Advances, 10.1039/C5RA17556A, 5, 86347-86354, 2015.10. |
| 38. |
Koichi Suematsu, Yuka Shin, Nan Ma, Tokiharu Oyama, Miyuki Sasaki, Masayoshi Yuasa, Tetsuya Kida, Kengo Shimanoe, Pulse-Driven Micro Gas Sensor Fitted with Clustered Pd/SnO2 Nanoparticles, Analytical Chemistry, 10.1021/acs.analchem.5b01767, 87, 8407-8415, 2015.07. |
| 39. |
Nan Ma, Koichi Suematsu, Masayoshi Yuasa, Kengo Shimanoe, Pd Size Effect on the Gas Sensing Properties of Pd-Loaded SnO2 in Humid Atmosphere, ACS Applied Materials and Interfaces, 10.1021/acsami.5b04380, 7, 15168-15625, 2015.06. |
| 40. |
Nan Ma, Koichi Suematsu, Masayoshi Yuasa, Tetsuya Kida, Kengo Shimanoe, Effect of Water Vapor on Pd-Loaded SnO2 Nanoparticles Gas Sensor, ACS Applied Materials and Interfaces, 10.1021/am509082w, 7, 5863-5869, 2015.03. |
| 41. |
Koichi Suematsu, Masayoshi Yuasa, Tetsuya Kida, Noboru Yamazoe, Kengo Shimanoe, Determination of Oxygen Adsorption Species on SnO2: Exact Analysis of Gas Sensing Properties Using a Sample Gas Pretreatment System, Journal of Electrochemical Society, 10.1149/2.004406jes, 161, B123-B128, 2014.04. |
| 42. |
Koichi Suematsu, Yuka Shin, Zhongqiu Hua, Kohei Yoshida, Masayoshi Yuasa, Tetsuya Kida, Kengo Shimanoe, Nanoparticle Cluster Gas Sensor: Controlled Clustering of SnO2 Nanoparticles for Highly Sensitive Toluene Detection, ACS Applied Materials and Interfaces, 10.1021/am500944a, 6, 5319-5326, 2014.03. |
| 43. |
Tetsuya Kida, Shuhei Fujiyama, Koichi Suematsu, Masayoshi Yuasa, Kengo Shimanoe, Pore and Particle Size Control of Gas Sensing Films Using SnO2 Nanoparticles Synthesized by Seed-Mediated Growth: Design of Highly Sensitive Gas Sensors, Journal of Physical Chemistry C, 10.1021/jp4045226, 117, 17574-17582, 2013.07. |
| 44. |
Noboru Yamazoe, Koichi Suematsu, Kengo Shimanoe, Gas reception and signal transduction of neat tin oxide semiconductor sensor for response to oxygen, Thin Solid Films, 10.1016/j.tsf.2013.03.139, 548, 695-702, 2013.04. |
| 45. |
Tetsuya Kida, Min-Hyun Seo, Koichi Suematsu, Masayoshi Yuasa, Yuichi Kanmura, Kengo Shimanoe, A Micro Gas Sensor Using TiO2 Nanotubes to Detect Volatile Organic Compounds, Applied Physics Express, 10.7567/APEX.6.047201, 6, 047201, 2013.04. |
| 46. |
Noboru Yamazoe, Koichi Suematsu, Kengo Shimanoe, Two types of moisture effects on the receptor function of neat tin oxide gas sensor to oxygen, Sensors and Actuator B Chemical, 10.1016/j.snb.2012.08.060, 176, 443-452, 2012.09. |
| 47. |
Koichi Suematsu, Masayoshi Yuasa, Tetsuya Kida, Noboru Yamazoe, Kengo Shimanoe, Effects of crystallite size and donor density on the sensor response of SnO2 nano-particles in the state of volume depletion, Journal of Electrochemical Society, 10.1149/2.107204jes, 159, J136-J141, 2012.02. |
| 48. |
Noboru Yamazoe, Koichi Suematsu, Kengo Shimanoe, Extension of Receptor Function Theory to Include Two Types of Adsorbed Oxygen for Oxide Semiconductor Gas Sensor, Sensors and Actuator B Chemical, 10.1016/j.snb.2012.01.020, 163, 128-135, 2012.01. |
