Electrohydrodynamic Printed Ultra-Micro AgNPs Thin Film Temperature Sensors Array for High-Resolution Sensing

• Published in: Micromachines (Basel) Vol. 14; no. 8; p. 1621
• Main Authors: He, Yingping, Li, Lanlan, Su, Zhixuan, Xu, Lida, Guo, Maocheng, Duan, Bowen, Wang, Wenxuan, Cheng, Bo, Sun, Daoheng, Hai, Zhenyin
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.08.2023; MDPI
• Subjects: Accuracy; Additive manufacturing; AgNPs; Agricultural production; Arrays; Cost analysis; electrohydrodynamic printing; Electrohydrodynamics; Film thickness; Glass substrates; Inkjet printing; Microelectromechanical systems; Multilayers; Nanoparticles; Nozzles; Porosity; Printers (Computers); Screen printing; Sensor arrays; Sensors; Silver; Temperature sensors; temperature sensors array; Thermometers; thin film; Thin films; ultra-micro; China
• ISSN: 2072-666X; 2072-666X
• DOI: 10.3390/mi14081621

Current methods for thin film sensors preparation include screen printing, inkjet printing, and MEMS (microelectromechanical systems) techniques. However, their limitations in achieving sub-10 μm line widths hinder high-density sensors array fabrication. Electrohydrodynamic (EHD) printing is a promising alternative due to its ability to print multiple materials and multilayer structures with patterned films less than 10 μm width. In this paper, we innovatively proposed a method using only EHD printing to prepare ultra-micro thin film temperature sensors array. The sensitive layer of the four sensors was compactly integrated within an area measuring 450 μm × 450 μm, featuring a line width of less than 10 μm, and a film thickness ranging from 150 nm to 230 nm. The conductive network of silver nanoparticles exhibited a porosity of 0.86%. After a 17 h temperature-resistance test, significant differences in the performance of the four sensors were observed. Sensor 3 showcased relatively superior performance, boasting a fitted linearity of 0.99994 and a TCR of 937.8 ppm/°C within the temperature range of 20 °C to 120 °C. Moreover, after the 17 h test, a resistance change rate of 0.17% was recorded at 20 °C.