Back
 MSA  Vol.11 No.2 , February 2020
Low-Temperature Formation of a WO3 Thin Film by the Sol-Gel Method Using Photo-Irradiation and Fabrication of a Flexible Hydrogen Sensor
Abstract: Hydrogen has been recently attracted much attention with respect to high energy-conversion efficiency and low environmental burden. However, hydrogen gas is dangerous due to an explosive gas and a fast combustion rate. Therefore, the development of hydrogen sensor with high accuracy and reliability that can detect hydrogen easily is required. Especially, a flexible hydrogen sensor is useful because it has a high degree of freedom with respect to the shape of location in which the sensor is to be located. A flexible hydrogen sensor—namely, a WO3 thin film formed on a PET film by the sol-gel method using photo irradiation—based on gasochromism of WO3 was developed. By irradiating a thin film, which was prepared by using WO3 precursor solution synthesized by the sol-gel method, with ultraviolet rays, a high-purity WO3 film could be prepared on PET at low temperature. The sensor was structured as a polystyrene (PS) film containing palladium (Pd) laminated on a WO3 film. The WO3 layer was porous, so the PS containing Pd atoms solution penetrated the WO3 layer. WO3 reacted with hydrogen gas and instantly turned blue as the transmittance of the WO3 layer changed. The sensor showed high reactivity even for hydrogen concentration below 4% (1%, 0.5%, 0.25%, and 0.1%), which was the lower limit of hydrogen ignition, and a linear relationship between hydrogen concentration and change in transmittance was found. Moreover, the resistance of the WO3 film significantly and instantaneously changed due to hydrogen-gas exposure, and the hydrogen concentration and resistance change showed a linear relationship. It is therefore possible to quantitatively detect low concentrations of hydrogen by using changes in transmittance and resistance as indices. Since these changes occur selectively under hydrogen at room temperature and normal pressure, they form the basis of a highly sensitive hydrogen sensor. Since the developed sensor is flexible, it has a high degree of freedom with respect to the shape of location in which the sensor is to be installed
Cite this paper: Ohishi, T. , Ueguri, K. and Nakamura, K. (2020) Low-Temperature Formation of a WO3 Thin Film by the Sol-Gel Method Using Photo-Irradiation and Fabrication of a Flexible Hydrogen Sensor. Materials Sciences and Applications, 11, 135-149. doi: 10.4236/msa.2020.112008.
References

[1]   Hydrogen Basic Strategy.
http://www.meti.go.jp/press/2017/12/20171226002/20171226002-1.pdf

[2]   The Strategic Road Map for Hydrogen and Fuel Cells, Industry-Academia-Government Action Plan to Realize Hydrogen Society.
http://www.meti.go.jp/press/2018/03/20190312001/20190312001-3.pdf

[3]   Ohira, E. (2013) The First Step for Realization of Hydrogen Society. Journal of Fuel Cell Technology, 13, 1.

[4]   Saito, A. (2014) Future Prospects for Supply and Demand of Hydrogen Energy. Journal of Fuel Cell Technology, 14, 9.

[5]   Kitaguchi, H. (2006) The Present Situation and Some Subjects of the Hydrogen Gas Sensor. Journal of Fuel Cell Technology, 6, 91-99.

[6]   Eranna, G., Joshi, B.C., Runthala, D.P. and Gupta, R.P. (2004) Oxide Materials for Development of Integrated Gas Sensors—A Comprehensive Review. Critical Reviews in Solid State and Materials Science, 29, 111-188.
https://doi.org/10.1080/10408430490888977

[7]   Sakai, G., Matsunaga, N. and Shimanoe, K. (2001) Theory of Gas-Diffusion Controlled Sensitivity for Thin Film Semiconductor Gas Sensor. Sensors and Actuators B: Chemical, 80, 125-131.
https://doi.org/10.1016/S0925-4005(01)00890-5

[8]   Nakagomi, S., Okuda, K. and Kokubunn, Y. (2003) Electrical Properties Dependent on H2 Gas for New Structure Diode of Pt-Thin WO3-SiC. Sensors and Actuators B: Chemical, 96, 364-371.
https://doi.org/10.1016/S0925-4005(03)00570-7

[9]   Zhao, M. and Ong, C.W. (2012) Improved H2-Sensing Performance of Nanocluster-Based Highly Porous Tungsten Oxide Films Operating at Moderate Temperature. Sensors and Actuators B: Chemical, 174, 65-73.
https://doi.org/10.1016/j.snb.2012.08.018

[10]   Zhang, C., Boudiba, A., Oliver, M.-G., Synders, R. and Debliquy, M. (2012) Magnetron Sputtered Tungsten Oxide Films Activated by Dip-Coated Platinum for PPM-Level Hydrogen Detection. Thin Solid Films, 520, 3679-3683.
https://doi.org/10.1016/j.tsf.2011.12.085

[11]   Sakaguchi, I., Saito, N., Watanabe, K., Adachi, Y. and Suzuki, T. (2016) Evaluation of Sensor Property for Hydrogen and Ethanol of Zinc-Doped Tin-Dioxide Thin Films Fabricated by RF Sputtering. Journal of the Ceramic Society of Japan, 124, 714-716.
https://doi.org/10.2109/jcersj2.16015

[12]   Nishio, K., Sei, T. and Tsuchiya, T. (1999) Preparation of Electrochromic Tungsten Oxide Thin Film by Sol-Gel Process. Journal of the Ceramic Society of Japan, 107, 199-203.
https://doi.org/10.2109/jcersj.107.199

[13]   Nakagawa, H., Yamamoto, N., Okazaki, S., Chinzei, T. and Asakura, S. (2003) A Room-Temperature Operated Hydrogen Leak Sensor. Sensors and Actuators B: Chemical, 93, 468-474.
https://doi.org/10.1016/S0925-4005(03)00201-6

[14]   Yamaguchi, Y., Kineri, T., Fujimoto, M., Mae, H., Yasumori, A. and Nishio, K. (2011) Investigation of Electrical Hydrogen Detection Properties of Pt/WO3 Thin Films Prepared by Sol-Gel Method. Key Engineering Materials, 485, 271-274.
https://doi.org/10.4028/www.scientific.net/KEM.485.271

[15]   Yamaguchi, Y., Imamura, S., Ito, S., Nishio, K. and Fujimoto, K. (2015) Influence of Oxygen Gas Concentration on Hydrogen Sensing of Pt/WO3 Thin Film Prepared by Sol-Gel Process. Sensors and Actuators B: Chemical, 216, 394-401.
https://doi.org/10.1016/j.snb.2015.04.020

[16]   Fardindoost, S., Iraji zad, A., Rahimi, F. and Ghasempour, R. (2010) Pd Doped WO3 Films Prepared by Sol-Gel Process for Hydrogen Sensing. International Journal of Hydrogen Energy, 35, 854-860.
https://doi.org/10.1016/j.ijhydene.2009.11.033

[17]   Yamaguchi, Y., Nemoto, C., Ito, S., Nishio, K. and Fujimoto, K. (2015) Improvement of Hydrogen Gas Sensing Property of the Sol-Gel Derived Pt/WO3 Thin Film by Ti-Doping. Journal—Ceramic Society Japan, 123, 1102-1105.
https://doi.org/10.2109/jcersj2.123.1102

[18]   Brinker, C.J. and Scherer, G.W. (1990) Sol-Gel Science. Academic Press, Boston.

[19]   Deb, S.K. (2008) Opportunities and Challenges in Science and Technology of WO3 for Electrochromic and Related Applications. Solar Energy Materials and Solar Cells, 92, 245-258.
https://doi.org/10.1016/j.solmat.2007.01.026

[20]   Pajonk, G.M. (2000) Contribution of Spillover Effects to Heterogeneous Catalysis. Applied Catalysis, 202, 157-169.
https://doi.org/10.1016/S0926-860X(00)00522-6

[21]   Ohishi, T., Maekawa, S. and Katoh, A. (1992) Synthesis and Properties of Tantalum Oxide Films Prepared by the Sol-Gel Method Using Photo-Irradiation. Journal of Non-Crystalline Solids, 147-148, 493-498.
https://doi.org/10.1016/S0022-3093(05)80665-9

[22]   Maekawa, S., Okude, K. and Ohishi, T. (1994) Synthesis of SiO2 Thin Films by Sol-Gel Method Using Photoirradiation and Molecular Structure Analysis. Journal of Sol-Gel Science and Technology, 2, 497-501.
https://doi.org/10.1007/BF00486297

[23]   Ohishi, T., Maekawa, S., Ishikawa, T. and Kamoto, D. (1997) Preparation and Properties of Anti-Reflection/Anti Static Thin Films for Cathode Ray Tubes Prepared by Sol-Gel Method Using Photoirradiation. Journal of Sol-Gel Science and Technology, 8, 511-515.
https://doi.org/10.1007/BF02436891

[24]   Okusaki, S. and Ohishi, T. (2003) The Effect of Photo-Irradiation in Hydrolysis and Condensation of Silicon Alkoxide. Journal of Non-Crystalline Solids, 319, 311-313.
https://doi.org/10.1016/S0022-3093(02)02054-9

 
 
Top