Advancing pressure sensors performance through a flexible MXene embedded interlocking structure in a microlens array

Piezoresistive composite elastomers have shown great potentials for wearable and flexible electronic applications due to their high sensitivity, excellent frequency response, and easy signal detection. A composition membrane sensor with an interlocked structure has been developed and demonstrated outstanding pressure sensitivity, fast response time, and low temperature drift features. Compared with a flexible MXene-based flat sensor (Ti3C2), the interlocked sensor exhibits a significantly improved pressure sensitivity of two magnitudes higher (21.04 kPa−1), a fast reaction speed of 31 ms, and an excellent cycle life of 5000 test runs. The viability of sensor in responding to various external stimuli with high deformation capacity has been confirmed by calculating the force distribution of a polydimethylsiloxane (PDMS) film model with a microlens structure using the solid mechanics module in COMSOL. Unlike conventional process, we utilized three-dimensional (3D) laser-direct writing lithography equipment to directly transform high-precision 3D data into a micro-nano structure morphology through variable exposure doses, which reduces the hot melting step. Moreover, the flexible pressure device is capable of detecting and distinguishing signals ranging from finger movements to human pulses, even for speech recognition. This simple, convenient, and large-format lithographic method offers new opportunities for developing novel human–computer interaction devices.