Investigation of Biodegradable Metals for Green and Sustainable Temperature Sensors

• Published in: IEEE journal on flexible electronics Vol. 3; no. 7; pp. 306 - 311
• Main Authors: Husain, Qazi Zahid, Corsino, Dianne, Krik, Soufiane, Stona, Andrea, Munzenrieder, Niko, Cantarella, Giuseppe
• Format: Journal Article
• Language: English
• Published: IEEE 01.07.2024
• Subjects: Flexible electronics; green electronics; Humidity; Immune system; poly-ether ether ketone (PEEK); Sensors; Substrates; sustainable thin-film devices; Temperature measurement; Temperature sensors; Zinc
• ISSN: 2768-167X; 2768-167X
• DOI: 10.1109/JFLEX.2024.3449832

The management of electronics waste and the development of sustainable end-of-life strategies are key aspects of the green evolution of the electronics industry. To address this global issue, we implemented thin-film resistance temperature detectors (RTDs) using green sensing metals, such as Mg, Mo, and Zn, and poly-ether ether ketone (PEEK), as a biocompatible, flexible, and thermally resistant substrate. The environmentally friendly RTDs were characterized in a range of temperature, from 25 °C to 70 °C, showing consistent response and average sensitivities of <inline-formula> <tex-math notation="LaTeX">1.1\times 10^{-1} </tex-math></inline-formula>%/°C, <inline-formula> <tex-math notation="LaTeX">7\times 10^{-2} </tex-math></inline-formula>%/°C, and <inline-formula> <tex-math notation="LaTeX">5.8\times 10^{-2} </tex-math></inline-formula>%/°C for Mg, Mo, and Zn, respectively. At a constant temperature 25 °C, the effect of humidity variation from 10% to 90% on the resistance of the sensors was observed to be <inline-formula> <tex-math notation="LaTeX">2.0\times 10^{-5} </tex-math></inline-formula>%/relative humidity (RH), <inline-formula> <tex-math notation="LaTeX">3.4\times 10^{-2} </tex-math></inline-formula>%/RH, and <inline-formula> <tex-math notation="LaTeX">5\times 10^{-3} </tex-math></inline-formula>%/RH, respectively, for Mg, Mo, and Zn RTDs. Furthermore, the sensor's response to mechanical strain was evaluated by bending the devices down to a 10-mm bending radius. In addition, the dissolution of the green RTDs in water allows the reusability of the substrate for a new fabrication batch, minimizing the amount of electronics waste generated. Through this study, a promising solution to environmental concerns, realizing is endowed for realizing temperature sensors, with applications in green and sustainable wearable systems is demonstrated.