Flexible dual functional piezoelectric pyroelectric sensor for high temperature applications

Prolonged operation of mechanical components under high-temperature environment severely affects their performance and service life. It is urgently needed a high-temperature resistance sensor to monitor local temperature changes in the component to enhance the safety. However, conventional sensors are difficult to simultaneously achieve excellent sensing performance and conformability at high-temperature environments for curved surfaces. Herein, a polyacrylonitrile (PAN)/zirconium acetate [Zr(OAc)_4]-based flexible and high-temperature-resistant piezo/pyroelectric bifunctional sensors are fabricated via heat treatment and typical package method. Incorporation of Zr(OAc)₄ reduced the cyclization temperature of PAN molecular chains and effectively enhanced both the mechanical properties and electrical output of the composite membranes sensor. Compared to pure PAN, the PAN/Zr(OAc)₄ composite nanofiber sensor (heat-treated at 450 °C) exhibits higher voltage output (~ 12.9 V) and piezoelectric sensitivity (~ 1.67 V/N) at room temperature. In addition, the sensor exhibits excellent pyroelectric output performance across a wide temperature gradient range, enabling accurate detection of engine temperature fluctuations. Remarkably, the sensor maintain stable piezoelectric and pyroelectric outputs after 5000 press-release cycles at 400 °C, highlighting its robustness under extreme conditions. These results demonstrate that PAN/Zr(OAc)₄ sensor provides reliable, flexible, and multifunctional solutions for real-time temperature monitoring in automobile engines, offering substantial benefits for extending engine lifespan and ensuring driving safety.