Ni-doped SiOC based tetrachiral honeycomb structure to activate efficient piezoresistivity and temperature detection performance

The Ni element is integrated at the molecular level of SiOC via precursor solution doping. Ni doped polymer-derived ceramic (PDC) SiOC improves its semiconductor properties and achieves efficient bifunctional pressure-temperature detection. Ni promotes the SiOC phase transition at high temperatures, thus increasing the content of the conductive phase, achieving the conductivity of 0.273 S/m. Massive conductive phase making it more susceptible to generate tunneling-percolation conduction effects and thereby enhancing piezoresistivity. Meanwhile, the band gap of SiNiOC is reduced, leading to fewer electrons transferring energy required and better temperature sensitivity. The optimized SiNiOC-1 attained maximum piezoresistivity and gauge factor (GF) values of 78.31 % and −662.56, respectively. The tetrachiral honeycomb structure was prepared by vat photopolymerization printing technology to enhance the piezoresistivity and ensure mechanical properties. The piezoresistivity of SiNiOC-1 remained unchanged after 500 times loading-unloading cycles, demonstrating its excellent long-term operational stability. Furthermore, SiNiOC-1 exhibited benign temperature monitoring capabilities from 50 °C to 800 °C and rapid thermal response characteristics. For temperature-resistance variation curve fitting, SiOC is appropriate for the Steinhart-Hart equation, while SiNiOC-1 and SiNiOC-2 are more adaptive to the thermistor equation.