Mass-produced, dispenser-printed single-electrode triboelectric nanogenerators for wearable applications: a simple approach

The burgeoning advancement in smart bionic technology has infused newfound vitality into the realms of medical and healthcare domains, as well as human-computer interaction. The emulation of human skin functions, particularly the haptic response function, stands as a pivotal aspect in electronic skin (e-skin) development. However, extant piezoresistive, piezoelectric, and capacitive conventional tactile sensors encounter limitations necessitating external input and power systems for information control and energy provision in practical applications. This study introduces a novel approach, employing a single-electrode triboelectric nanogenerator (TENG) array fabricated through an all-dispensing printing method, simultaneously serving the dual purposes of biomotor recognition and energy harvesting. The configuration involves the utilization of Ag/MWCNT/PDMS composite electrode inks, leveraging PDMS as an elastic wrapping carrier. The design incorporates a bridged conductive network structure, achieved through the sheet structure of the silver paste and the tubular structure of carbon nanotubes. This ensures both high conductivity and favorable flexibility and printing characteristics. The resultant TENG exhibits notable features, including a peak open-circuit voltage of 172 V, a short-circuit current of 94 mu A, a load resistance of 1 M Omega, and a maximum power output of 0.58 mW. Exploiting the heightened sensitivity of the single-electrode TENG, the study successfully demonstrates its capacity to discern various human motion patterns, such as finger tapping, clapping, and hammering. Additionally, owing to its exceptional spatial sensitivity, the printed TENG array facilitates the realization of flexible virtual keyboard applications. This high-performance, easily mass-producible e-skin unit not only paves the way for advancements in wearable devices but also holds promise for a diverse array of applications. We prepared ultra-flexible electrodes for wearable TENG applications by modifying commercial silver paste inks and employing a dispensing printing technique.