Reduced Graphene Oxide Interlocked Carbonized Loofah for Energy Harvesting and Physiological Signal Monitoring

Highly conductive carbonaceous nanomaterials derived from biomass fibers (e.g., loofah) have been extensively employed in flexible sensors. Nonetheless, the even texture of the carbonized loofah (CL) constrained the contact surface area with adjacent fibers, given its conductivity. Herein, the CL interlocked by the reduced graphene oxide (rGO) nanosheets was employed to construct highly conductive hydrogel, which served as the sensor module and triboelectric nanogenerator (TENG) module in a self-powered sensing system. Originating from the π–π interaction, the rGO can be firmly fixed on the surface of CL and act as a bridge to reduce the electron transfer gap, thereby resulting in accelerated electron transport. Compared to pristine CL hydrogel, the electrical conductivity of CL@rGO hydrogel was improved from 28.5 S/m to 55.2 S/m and exhibits improved performance in terms of electrical output when incorporated into TENG and sensor devices. The built-up CL@rGO sensor exhibited remarkable durability for more than 10,000 cycles, maximum gauge factor (GF) of 16021 and rapid response time of 20 ms. Due to these attributes, the sensor is capable of efficiently monitoring the capacity for complex human activities. CL@rGO exhibits considerable potential across multiple domains, encompassing wearable electronics, artificial intelligence devices and human-machine interaction, owing to its adaptable characteristics.