Electric-Ray-Inspired Universal Island-Bridge Structure for Transforming Nonpyroelectric Substrates into Pyroelectric Sensors

Large-area, flexible pyroelectric sensors have received increasing attention in a range of applications including electronic skin, robotics, and military. However, existing flexible pyroelectric sensors struggle to achieve both high pyroelectric performance and excellent mechanical properties simultaneously. Here, we propose a universal island-bridge percolation structure inspired by the electric organ of the electric ray that can enable flexible nonpyroelectric substrates with excellent mechanical properties to generate a pyroelectric effect. The island-bridge percolation network structure made of pyroelectric particles (island) and carboxyl-functionalized multiwalled carbon nanotubes (bridge) achieved the transmission and superposition of the pyroelectric effect through the film polarization and percolation effect. The pyroelectric sensor based on the island-bridge percolation network structure not only inherits the pyroelectric properties of the pyroelectric particles but also inherits the excellent mechanical properties of the nonpyroelectric substrates. The flexible pyroelectric sensors fabricated from polydimethylsiloxane (PDMS) substrates exhibit a good pyroelectric effect and excellent mechanical reliability even under 30% tensile rate and 5,000 tensile–retraction cycles, and those made from polyimide (PI) substrates can serve as electronic skin for robots to detect heat sources and possess infrared sensing properties with a maximum distance of 8 cm. This study provides ideas to fabricate flexible pyroelectric sensors with highly flexible and high-performance properties.