Fig. 3: Electromechanical behaviors of the MoWNb MEA-based flexible strain sensors.

a Relative change in resistance of a single sensor as a function of the applied microstrains at various temperatures from −150 °C to 900 °C. The solid lines are the linear fitting results, showing the linearity and GFs. b Comparison of the GF values and the working temperature regime among the printed flexible strain sensors in the current study and the representative high-temperature strain sensors based on metals, metal alloys, ceramics, carbons, polymers, and semiconductors reported in the literature. GFs are absolute values for easy comparison. c Long-term stability and durability of the MEA sensor tested at 900 °C with the maximum microstrain of 258 μɛ. The almost identical electrical outputs are well maintained throughout the entire 1200 bending cycles. d Relative change in resistance of the MEA sensor under tiny and large strains from 0.57 μɛ to 4541 μɛ. There is a consistent response in several bending and releasing cycles. e Comparison of detection limit, maximum strain, and working temperature range for various high-temperature strain sensors and stretchable strain sensors. f Photographs of a sensor array under tensile strain and the measurement setup for evaluating the output of the four sensing branches under bending operation. g Distribution of the relative change in resistance in the MEA sensitive layer when different branches of the sensor array are pressed individually.