Tetrachiral honeycomb regulated polymer-derived SiFeOC ceramics with tunable piezoresistive effect

Sensitivity-adjustable piezoresistive SiFeOC ceramic with tetrachiral honeycomb structures has been presented for pressure detection under harsh environments. The 3D structuralized piezoresistive structures exhibited marked structure-dependent sensing performance, providing another dimension for detection limit and sensitivity tunning. Digital light processing technique printed the Fe-doped SiOC tetrachiral honeycombs, in which Fe acted as a dopant for conductivity modification. Due to the activation of the percolation network consisting of free carbon in an amorphous matrix, the conductivity of the SiFeOC sensing structure reached 3.08 S/m. Meanwhile, the sensitivity of the structures can be optimized by adjusting rotation angles due to the negative Poisson's ratio (NPR) characteristics that provided tunable modulus, leading to a rise in the gauge factor from 169 to 796. The rotation angle adjustment also optimized the mechanical performance of the sensing structure, yielding a compression strength of 24.11 MPa. The robustness in load-bearing capacity also ensured long-term cyclic detection stability, realizing an intelligent piezoresistive structure with high strength and environmental tolerance.