Screen-Printed, Flexible, and Eco-Friendly Thermoelectric Touch Sensors based on Ethyl Cellulose and Graphite Flakes Inks

Abstract Despite the undoubtable interest in energy conversion, thermoelectric materials can be approached from a temperature-sensitive perspective, as they detect small thermal stimuli, such human touch or contact with cold/hot objects. This feature offers possibilities for different applications being one of them integration scalable and cost-effective, biocompatible, flexible, lightweight sensing solutions, exploring combination sustainable Seebeck coefficient-holding printing techniques flexible substrates.
In this work, ethyl cellulose graphite flakes inks were optimized to used functional material sensors produced by screen-printing. Graphite concentrations 10, 20 30 wt% tested, 1, 2 3 printed layers on four substrates - office paper, sticker label standard cotton, organic cotton. The conjugation these variables was assessed terms printability, sheet resistance response. best electrical-thermoelectric output is achieved ink paper substrate. Subsequently, up 48 elements increase voltage response (> 4.5 mV) promoted gloved finger touch. Fast repeatable recognition obtained devices signal-to-noise ratio 340 rise times bellow 0.5 s. results evidence that screen-printed graphite-based are highly suitable applications.