Large‐Area 2D Metasurface‐Based Triboelectric E‐Skin Arrays: Contact & Proximity Tactile Mapping with Broadband Acoustic Readouts

Abstract

ABSTRACT Recent advances in electromechanically coupled, self‐powered, flexible transducer‐enabled electronic skins are predominantly driven by the capacitive triboelectric nanogenerators (TENGs), which operate intrinsically as multifunctional sensor‐cum‐energy harvester. The resulting TENG's operability in cutting‐edge wearable technologies can be significantly augmented by introducing 2D dielectric metasurfaces, which optimize functionality through enhanced electromechanical coupling. Here, we introduce a 2D metasurface‐TENG e‐skin that unifies tactile (contact and inductive) and acoustic sensing in a single ultrathin platform. Large‐area nanocone (NC) metasurfaces are engineered on 100 µm polydimethoxysilane (PDMS) films via laser‐interference lithography (LIL) and soft molding, which boosts triboelectric charge density and provides optical diffraction cues for strain monitoring. Integrated into a 3 × 3 array, the device delivers real‐time tactile pressure imaging with low crosstalk and non‐contact proximity detection. The NC‐TENG patch also functions as a self‐powered acoustic sensor, in which the sound pressure level (SPL) and frequency response are quantified in both spatial and spectral domains over a broad frequency range (∼50–6400 Hz). Compared to pristine PDMS, the metasurface enhances open‐circuit voltage by ≈46% under identical loading and sustains stable electrical output. By coupling electromechanical and electro‐acoustic transductions with metasurface optics, this work advances multimodal, arrayed e‐skins for next‐generation human‐machine interfaces and wearable sensing.