Reviving acoustic sensing via a triboelectric nanogenerator: principle, progress, and perspective

The rise of intelligent manufacturing engineering has brought increased attention to acoustic sensors for precise perception and human-machine interaction. Recently, triboelectric nanogenerators (TENGs) have emerged as one of the most promising technologies for developing self-powered acoustic sensors, owing to their wide range of material options, simple structure, flexibility, and cost-effectiveness. More importantly, the rapid saturation constitutive characteristics of contact-separation (C-S) mode TENGs offer high sensitivity and an excellent signal-to-noise ratio (SNR) for detecting micro-scale mechanical signals. This article provides an overview of TENG-based acoustic sensors developed over the past five years, focusing on working principles, comparisons with piezoelectric nanogenerators (PENGs), fabrication methods, core structures, sensing materials, and intelligent applications in both air and underwater environments. Furthermore, technical constraints and potential innovation pathways for triboelectric acoustic sensors are explored. Notably, we propose a practical figure of merit that integrates both displacement and transferred charges to synergistically evaluate the performance of triboelectric devices. With continued research in this area, triboelectric acoustic sensors are expected to gain increasing attention in the detection of micromechanical quantities with ultrahigh sensitivity, thereby advancing the development of intelligent manufacturing technologies.