Temporally shaped femtosecond laser liquid-phase processing of PVDF-laser-induced graphene/graphene for flexible micro-supercapacitor sensors

An environmentally-friendly temporally shaped femtosecond laser strategy is developed for fabricating functional composites. • A ″ lamellar LIG–nanographene particle " composite layer was fabricated via femtosecond laser dual-pulse processing. • The resulting MSCs achieve an area-specific capacitance of 58.25 mF cm −2 , 3.7 times higher than pure LIG-based devices. • Optimizing the pulse delay to 20 ps further increases the capacitance to 162 mF cm −2 with cycling stability. • Integrated into a flexible sensor, the MSC demonstrates high-sensitivity detection of physiological signals across multiple body regions. This study proposes a temporally shaped femtosecond laser liquid-phase strategy for in-situ functionalization of poly(vinylidene fluoride) (PVDF) film to overcome prevalent limitations of micro-supercapacitor (MSC)-based flexible sensors, including constrained processing precision and intractable material performance optimization. Interaction between femtosecond dual pulses and PVDF triggers in-situ surface graphitization, yielding a lamellar laser-induced graphene (LIG) architecture. Concurrently, the laser dissociates graphene sheets in the dispersion into nanoparticles that firmly anchor onto LIG, constructing a hierarchical “lamellar LIG–nanographene particles” composite functional layer. Integrating femtosecond laser direct-writing patterning, temporally shaped based MSCs were fabricated. Systematic tuning of inter-pulse delay via temporally shaped identified an optimal 20 ps delay, yielding devices with areal capacitance (162 mF cm −2 ), energy density (14.40 μWh·cm −2 ), cycling stability (97.81% after 10,000 cycles), and robust durability. Flexible sensors assembled with the MSC achieved highly sensitive monitoring and distinct signal discrimination of diverse human physiological activities. This work establishes a novel laser processing paradigm for flexible micro-energy storage devices and provides a versatile material/device platform to advance flexible electronic systems for health monitoring, human–computer interaction, and sports rehabilitation. Download: Download high-res image (297KB) Download: Download full-size image