2D/1D van der Waals material-based composites for wearable thermoelectric generators and sensors

Abstract

Traditional heterostructures, bound by covalent bonds, are limited to materials with similar lattice structures. Utilizing van der Waals (vdW) forces to assemble low-dimensional materials allows for the integration of diverse materials, overcoming lattice-matching and processing constraints, and enabling the creation of versatile vdW-material-based composites. A transition metal dichalcogenide two-dimensional (2D) material, TaS₂, has undergone extensive research in various fields but challenges are encountered in the enhancement of its thermoelectric performance. Herein, one-dimensional (1D) silver nanowires (Ag NWs) have been integrated with 2D TaS₂ via vdW forces, to form 1D/2D vdW-material-based composites. With further addition of polymer binder, PEDOT:PSS, a flexible 1D/2D film was developed. The power factor was enhanced by nearly a factor of 5 due to the bridging effect. The tensile strength was tripled due to the bricks and mortar structure. About 20 nW power was generated by a six-legged module at a temperature difference of 30 K. Demonstrations of the composite in tactile, respiration, and strain sensors showed significant promise for assisting the visually impaired with language support and enabling real-time measurements of respiratory rates and physiological conditions for health monitoring. This study underscores the vast potential of 1D/2D vdW composite films for applications in wearable nanogenerators, sensors, and beyond.