Magnetically Enhanced Carbon:SPION-Infused Conducting Gel for Wearable Triboelectric Sensors

Conducting gels have attracted significant attention due to their exceptional flexibility, conductivity, and biocompatibility for various health monitoring sensors. Despite advancements in the conducting gel, they suffer from low conductivity and sensitivity when employed in wearable devices. Hence, this work mainly focuses on developing a unique magneto-responsive highly conducting gel by embedding a carbon:superparamagnetic iron oxide nanoparticle (C:SPION) composite in poly(vinyl alcohol)/silver nitrate (PVA/AgNO3). The well-dispersed C:SPION serves as a conducting filler due to the delocalized π electrons in carbon, contributing to improve electrical conductivity. The magnetic domains and molecular interaction in the PVA/AgNO3/C:SPION conducting gel were examined using magnetic force microscopy (MFM), vibrating sample magnetometry (VSM), and Raman spectroscopy. The developed conducting gel achieved a high zeta potential, d33 coefficient, electronic conductivity, storage modulus, tensile strength, and magnetic moment of 0.13 mV, 26 pC/N, 38 kS/m, 6.6 kPa, 0.5 MPa, and 2.34 emu/g, respectively. Further, synthesized conducting gel was employed to fabricate a wearable triboelectric nanogenerator (C-TENG), delivering an output voltage of 276 V and a current response up to 8.6 μA. C-TENG efficiently produces an output power density of 1.67 mW/cm2 and is capable of charging a 1 μF to 10 μF capacitor within 68 s. Additionally, the C-TENG device was analyzed under varying magnetic fields from 0.032 to 0.12 T. Moreover, the developed conducting gel demonstrated versatility across various applications such as wearable strain sensors, efficient electrical signals to illuminate 39 commercial LEDs, capacitive touch screen sensitivity, real-time pulse monitoring, and use as a self-powered interface for human–machine interaction to enable smart electric lamp.