Fluorescent Sulfur Quantum Dot Reinforced PVA Hydrogel with Integrated Self-Powered Sensing and Triboelectric Energy Harvesting for Wireless Motion Monitoring

A multifunctional composite hydrogel with integrated self-powered sensing and energy harvesting capabilities was developed through rational structural design of sulfur quantum dot (SQD)-reinforced polymer networks. By incorporating SQDs (0.7 wt %) with abundant polar groups into a poly(vinyl alcohol)/carboxylated cellulose nanofiber matrix (PCS-7), the resultant PCS-7 hydrogel exhibited synergistic enhancement in both mechanical and electrical properties, achieving a remarkable tensile strength of 0.22 MPa (100% increase) and a conductivity of 1.4 S/m (70.7% increase) compared to hydrogels without SQDs. The PCS-7 hydrogel sensor also demonstrated a strain sensitivity of GF = 3.1. The SQDs served as cross-linkers, improving the hydrogel’s cyclic stability over 1000 cycles. Furthermore, a PCS-based triboelectric nanogenerator (TENG) achieved an open-circuit voltage of 91 V, short-circuit charge of 27.02 nC, and short-circuit current of 0.63 μA. With integrated wireless Bluetooth transmission and TENG technologies, this composite demonstrated the ability to sense large-scale motions. This work not only showcases a unique fluorescent effect from the SQDs but also integrates traditional hydrogel systems with modern wireless sensing technology, optimizing the hydrogel’s stretchability and advancing the design of intelligent hydrogel composites for next-generation wearable electronics and self-powered systems.