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Suematsu Koichi Last modified date:2019.08.23

Assistant Professor / Functional and Structual Materials Science
Department of Advanced Materials Science and Engineering
Faculty of Engineering Sciences


Graduate School
Undergraduate School


E-Mail
Homepage
http://www.mm.kyushu-u.ac.jp/lab_03/en/index.html
Phone
092-583-7539
Fax
092-583-7538
Academic Degree
Dr. Engineering
Field of Specialization
Functional inorganic materials
Research
Research Interests
  • Design of dielectric thin films using Organic/Inorganic composite nanoparticles
    keyword : BaTiO3 nano-particles, highly dispersed sol
    2014.04.
  • Materials design and advantages of semiconductor gas sensors
    keyword : semiconductor nano-particle, micro structure, gas diffusion
    2012.04.
Academic Activities
Papers
1. Koichi Suematsu, Wataru Harano, Yuki Hiroyama, Ken Watanabe, Kengo Shimanoe, Ultra-High Sensitive (Ppt) Gas Sensor Based on the Pulse Heating Using MEMS Technique, Multidisciplinary Digital Publishing Institute Proceedings, 14, 24, 2019.06.
2. Koichi Suematsu, Wataru Harano, Tokiharu Oyama, Nan Ma, Ken Watanabe, Kengo Shimanoe, ULTRA-HIGH SENSITIVE GAS DETECTION USING PULSE-DRIVEN MEMS SENSOR BASED ON TIN DIOXIDE, Proceedings of ISOEN2019, 2019.05.
3. 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.
4. 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.
5. 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.
6. 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..
7. 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.
8. 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.
9. 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.
10. 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..
11. 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.
12. 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.
13. 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.
14. 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.
15. 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.
16. 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.
17. 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.
18. 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.
19. Tetsuya Kida, Aya Nishiyama, Zhongqiu Hua, Koichi Suematsu, Masayoshi Yuasa, Kengo Shimanoe, WO3 Nanolamella Gas Sensor: Porosity Control Using SnO2 Nanoparticles for Enhanced NO2 Sensing, Langmuir, 10.1021/la4049105, 30, 2571-2579, 2014.02.
20. 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.
21. 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.
Presentations
1. Koichi Suematsu, Ultra-high sensitive (ppt) gas sensor based on the pulse heating using MEMS technique, 8th GOSPEL Workshop, 2019.06.
2. Koichi Suematsu, Wataru Harano, Tokiharu Oyama, Nan Ma, Ken Watanabe, Kengo Shimanoe, ULTRA-HIGH SENSITIVE GAS DETECTION USING PULSE-DRIVEN MEMS SENSOR BASED ON TIN DIOXIDE, 18th International Symposium on Olfaction and Electronic Nose (ISOEN), 2019.05.
3. Koichi Suematsu, Sun Yongjiao, Ken Watanabe, Maiko Nishibori, Kengo Shimanoea, Analysis of Oxygen Adsorption on Surface of Metal Oxide to Understand Sensing Mechanism of Semiconductor Gas Sensors, 12th Asian Conference on Chemical Sensors, 2017.11.
4. Koichi Suematsu, Nano-Scale Particles Design of Metal Oxide Semiconductor Gas sensors for Environmental Protection, The 18th International Symposium on Eco-materials Processing and Design (ISEPD 2017), 2017.02, To detect the harmful gases in atmosphere using gas sensors is important for environment protection. Recently, the building gas sensors with high performance such as high gas sensitivity, rapid response and recovery, gas selectivity, and humidity resistance are strongly required. Resistive-type semiconductor gas sensors, especially SnO2-based gas sensors, are attracting the most attention because of their high potentiality. So far, we have reported that the introduction of three key factors, receptor function, transducer function and utility factor, to material design of sensors gives ultrahigh sensitivity in ppb level. However, the decrease in electric resistance by water vapor poisoning is most fundamental problem for practical use, because atmospheric environment includes water vapor and also the amount is different in each time and place. Recently, we tried to overcome such weak-point on SnO2-based gas sensors from viewpoint of materials design. For example, the decrease in electric resistance by water vapor poisoning can be improved by surface Sb substitution. Such materials design can raise the sensor performances and allow the practical use for environmental protection..