Nanotechnology-Driven Triboelectric Nanogenerators: Materials, Mechanisms, Applications, and Sustainable Pathways to Commercialization

The increasing global demand for clean, portable, and sustainable energy sources is propelled by the growth of wearable electronics, Internet of Things (IoT) devices, and environmental monitoring, which has led to increased attention towards technologies that are capable of harvesting low-frequency mechanical energy. Triboelectric nanogenerators (TENGs) have emerged as a promising solution owing to their lightweight design, low cost, and high energy conversion efficiency. This review is motivated by the urgent need to advance TENG technology from lab-scale concepts to real-world applications. We provide a comprehensive yet easy-to-understand overview of the fundamental working principles, operational modes, and material classifications of TENGs. We focus on nanomaterials, such as graphene, carbon nanotubes, and metal-organic frameworks, that improve performance and permit scaling up. The review also addresses practical challenges, including material degradation, fabrication bottlenecks, and integration with existing systems. In addition, sustainable design pathways using biodegradable and recyclable materials are discussed to support green energy solutions. Researchers, engineers, and product developers in flexible electronics, self-powered sensing, and sustainable device design will find this review valuable for guiding innovation and commercialization efforts. This work outlines a forward-looking roadmap for developing next-generation TENG-based energy systems by bridging scientific advances with practical deployment.