Sensors for general conditions in industrial production and life have been widespread, but rarely suited for extreme environments. The traditional method is replaced by digital light processing (DLP) to obtain unique structure customization. Doping Al promotes phase transition and hybridized transformation as well as affects the valence band value.
Ascribed to the existed conductive phase and generated tunneling-percolation conduction effect, the champion piezoresistivity and gauge factor of the 2 wt% aluminum acetylacetonate doped SiOC (SiAlOC-2) are 75.44 % and − 647.49. The addition of additives improves mechanical and pressuretemperature response performance, resulting in optimal compressive strength and Young’s modulus reaching 40.86 MPa and 16.55 GPa. Both SiOC and SiAlOC-2 exhibit benign temperature monitoring reaching 1000 ℃.
Al addition in SiOC ceramics promotes the formation of SiO2, graphite, and β-SiC, enhancing CF graphitization and hybridization while inhibiting carbon cluster growth. This leads to a slight decrease in SiAlOC's Eg and an upward shift in the valence band, reducing charge transition energy requirements. Al doping significantly improves mechanical properties and conductivity, supporting tunneling-percolation and boosting piezoresistivity. Notably, SiAlOC-2 exhibits superior piezoresistivity (75.44%) and gauge factor (GF -647.49), along with outstanding long-term stability and high-temperature durability. Its piezoresistivity remains stable after exposure to 1100°C for 2 hours. Using thermistor and Steinhart-Hart models, SiAlOC-2 can also serve for real-time temperature sensing.
Conclusions
SiAlOC-2 and SiOC own favorable pressure and temperature response properties. the resistance-temperature variation rule of SiOC is suitable for the thermistor equation while the counterpart SiAlOC-2 abides by the Steinhart-Hart formula. As a result, the difunctional SiAlOC sensor with high piezoresistivity performance and meeting high temperature detection is achieved via excellent design flexibility and manufacturing speed of 3D printing technology.