A flexible dual-function ZnO/Laser-induced graphene sensor with integrated temperature sensing and Joule heating

Dual-functional ZnO/LIG sensor made via 1-step laser direct writing. • Combines sensitive NTC temperature sensing and efficient Joule heating. • Exhibits high sensing linearity (R 2 = 0.9988) and max TCR of −3.65%. • Rapid heating rate of 2.68 °C s −1 at 24 V with electrothermal stability. • Zigzag design enables high bending durability and multi-site monitoring. Traditional flexible temperature sensors and heaters often suffer from discrete architectures, delayed thermal responses, and poor stability. To address these limitations, a zigzag-patterned dual-function ZnO/LIG sensor featuring independently operable temperature sensing and Joule heating functions is fabricated via one-step laser direct writing on a ZnCl 2 -doped polyimide (PI) film. This induces the in-situ growth of ZnO nanoparticles within a three-dimensional LIG scaffold, constructing a hierarchical porous structure that enhances electron transport and interfacial heat transfer. Fundamentally, first-principles DFT calculations verify strong interfacial orbital hybridization, which modulates carrier behaviors and significantly improves thermoresistive responses. Consequently, the device demonstrates stable negative temperature coefficient (NTC) characteristics (20–80 °C) with excellent linearity (R 2 =0.9964), a total relative resistance change of −3.65%, and an average temperature coefficient of resistance (TCR) of −0.061 °C −1 . It simultaneously exhibits efficient Joule heating, achieving 2.68 °C s⁻¹ at 24 V with stable temperature elevation during stepwise cycling. The zigzag electrode architecture effectively releases deformation stress, ensuring reliable baseline resistance without significant degradation after repeated bending cycles. Ultimately, this synergistic optimization accurately captures minute variations for precise body temperature mapping, respiration monitoring, and rapid deicing, providing a cost-effective, scalable strategy for flexible thermal-control equipment. Download: Download high-res image (233KB) Download: Download full-size image