Electrohydrodynamic-Printed AgNPs/PR Thin-Film Temperature Sensors With Micro Dimensions and Higher Temperature Measurement Capabilities

• Published in: IEEE sensors journal Vol. 24; no. 11; pp. 17441 - 17451
• Main Authors: Gong, Xiuliang, Cheng, Bo, Zhang, Chengfei, Wang, Bo, He, Yingping, Guo, Maocheng, Su, Zhixuan, Duan, Bowen, Hai, Zhenyin
• Format: Journal Article
• Language: English
• Published: New York IEEE 2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: AgNPs/polyester resin (PR); Drift rate; electrohydrodynamic (EHD) printing; Electrohydrodynamics; Encapsulation; Film thickness; Ink; micro; Optical sensors; Oxidation; Performance tests; Polyester resins; Printing; Sensors; Silicon dioxide; Solvents; Structural integrity; Substrates; Temperature measurement; temperature sensor; Temperature sensors; thin film; Thin films
• ISSN: 1530-437X; 1558-1748
• DOI: 10.1109/JSEN.2024.3388148

Conflicts between the existing temperature-resistant ink and printing window currently prevent electrohydrodynamic (EHD)-printed thin-film temperature sensors from achieving both fine linewidth and a higher temperature measurement limit simultaneously. In this study, we propose a method to adjust the existing AgNPs ink to prepare thin-film temperature sensors with micro dimensions and enhanced temperature measurement capabilities. The method involves leveraging the solubility of polyester resins (PRs) in alcohol-ether solvent to incorporate PR into a nano-silver solution in the same solvent system. This allows for easy printing while using the temperature-resistant properties of PR to anchor conductive networks. The AgNPs/PR film sensitive layer has an area less than <inline-formula> <tex-math notation="LaTeX">800\times 800\,\,\mu \text{m} </tex-math></inline-formula>, with an average linewidth of under <inline-formula> <tex-math notation="LaTeX">50 ~\mu \text{m} </tex-math></inline-formula> and a film thickness of approximately 700 nm. The unencapsulated AgNPs/PR film sensitive layer demonstrates long-term conductivity at 400 °C, while maintaining its structural integrity. Furthermore, performance test results indicate that AgNPs/PR film temperature sensors without encapsulation have a temperature measurement upper limit of 400 °C, but they are susceptible to oxidation drift at this temperature. To eliminate oxidation, SiO2 encapsulation is prepared. Experimental results demonstrate that AgNPs/PR film temperature sensors with SiO2 encapsulation achieve a temperature measurement upper limit of 407 °C. At this temperature, the resistance drift rate (RDR) is −0.0496%/h. After three rounds of testing, the change rate of the sensor resistance at 100 °C was −0.281%. The successful fabrication of the sensor using EHD printing suggests the potential of this sensor for applications in high-density temperature sensing requirements.