Ultra-stable Flexible Thermal Sensing Operating from 20 to 1273 K Enabled by the Directly Grown Mo₂C Patterns on Flexible Substrates

Transition metal carbides (TMCs) are promising candidates for applications in flexible sensing electronics due to their high intrinsic conductivity, excellent mechanical strength, and mechanical flexibility. However, it remains a critical challenge to synthesize patterned TMCs films on flexible substrates for direct fabricating flexible sensors with superior mechanical and thermal stability under high-temperature environments. Herein, we report an inkjet printing and hydrogen-assisted thermal reduction approach that enables in situ growth of Mo₂C patterns on flexible mica at 750°C. Thickness of the Mo₂C films can be modulated from 10 to 70 nm, while the electrical resistance ranges from 2 to 0.1 kΩ by tailoring inkjet printing cycles. Owing to the large cohesive energy and high bonding strength between the Mo₂C layer and the substrate, the resultant flexible temperature sensors show remarkable sensing performance from 20 to 1273 K, a high temperature coefficient of resistance of 1.7%/K (in the temperature regime over 1200 K), a low response time of about 26 ms, and a thermal stability at 873 K for 4 h. The proposed approach endows a promising platform to design thermally robust flexible sensors for applications in high-temperature environments.