Intrinsic Direct-Current Generation in an All-Paper-Based Triboelectric Nanogenerator via Asymmetric Interfacial...

The rapid growth of wearable electronics and distributed sensor networks has increased the demand for sustainable and low-loss power technologies. Here, we report a fully paper-based direct-current triboelectric nanogenerator (DC-TENG) fabricated through a water-processable and low-temperature strategy using biodegradable Xuan paper and environmentally benign functional materials. Unlike conventional triboelectric nanogenerators that rely on petroleum-derived fluorinated polymers such as polydimethylsiloxane (PDMS) and polytetrafluoroethylene (PTFE), the proposed device is entirely free of fluorinated triboelectric materials and nondegradable elastomeric substrates, thereby improving material sustainability and reducing environmental impact. The device integrates PEDOT:PSS/PVA/pullulan and graphene/carboxymethyl cellulose (CMC) hybrid layers to establish an electronically asymmetric interface capable of generating intrinsic direct-current output without external rectification. The graphene-mediated interface creates interfacial band bending and built-in electric fields that facilitate directional charge transport, while the porous cellulose framework improves conformal contact and charge separation. As a result, the device delivers a maximum output power of approximately 0.32 µW (0.8 mW m^{- 2}). The entirely solution-processable fabrication eliminates vacuum deposition and complex microfabrication, providing a simple, sustainable, and scalable platform for battery-free wearable electronics and self-powered sensing systems.