Single‐Step Fabrication of Monolithic Flexible Capacitive Pressure Sensors With Enhanced Sensitivity via Femtosecond Laser Direct Writing and Microhole Structuring

Flexible capacitive pressure sensors (CPSs) have attracted a lot of interest due to their potential applications in wearable electronics. Manufacturing flexible CPSs involves multiple steps to fabricate sensitive layers, electrode layers, and various sensitivity‐amplifying microstructures. Despite significant advancements, there remains a critical need to simplify the fabrication processes, enhance the sensitivity, and create more compact pressure sensors. In this study, a single‐step fabrication of a flexible CPSs in a gelatin matrix mixed with silver nitrate is reported. A seamless monolithic design is achieved by using a femtosecond laser‐based direct writing technique to pattern silver electrodes in gelatin. This approach offers high‐precision 3D fabrication of metallic silver in a single step. To increase sensitivity, microholes are fabricated in the gelatin layer using an amplified laser beam with the same fabrication setup. The microholes filled with air instigate a large variation in dielectric permittivity of a medium between two electrodes under applied pressure, resulting in enhanced sensitivity ≈2.44 kPa −1 in the range of 0–0.5 kPa. This work highlights the potential of femtosecond laser‐based direct writing of flexible sensors in next‐generation wearable technologies, providing a pathway for high‐performance solutions and a streamlined fabrication approach.