Dynamic-junction triboelectric nanogenerators: Underlying physics, interface charge-generation mechanisms, and design frameworks for enhanced harvesting and sensing performance

Abstract

The increasing demand for sustainable energy solutions has driven the advancement of technologies capable of converting ambient mechanical energy into electrical power. Among these, triboelectric nanogenerators (TENGs) have emerged as a prominent platform for broad-based energy harvesting. This review provides an overview of recent developments in dynamic junction-based TENGs, highlighting approaches that extend beyond conventional solid-solid (S-S) contact-separation mechanisms to encompass charge generation at liquid-solid (L-S), liquid-liquid (L-L), and liquid-gas (L-G) interfaces. Dynamic-junction TENGs are defined as triboelectric systems in which mechanically evolving interfaces regulate charge generation, separation, or collection. Under this framework, dynamic junctions encompass both material interfaces—such as S–S, L–S, L–L, L–G, and G–S—and electronically active semiconductor junctions, including Schottky, p–n, and heterojunction-based tribovoltaic nanogenerators. We provide a comparative analysis of the fundamental working principles of TENGs and the distinct charge generation mechanisms intrinsic to each interface type. The review discusses the theoretical frameworks relevant to dynamic-junction TENGs according to their domains of applicability, including the capacitive model and Maxwell’s displacement current for electrostatic-induction-based devices, Wang’s electron-cloud model for microscopic solid–solid contact electrification, and electric-double-layer-based models for liquid-containing interfaces. Furthermore, we categorize and scrutinize advanced design strategies, from interface-specific innovations and materials engineering to system-level integration and hybridization, all aimed at significantly enhancing output performance. The review highlights the representative applications of dynamic junction-based TENGs in diverse fields such as wearable electronics, environmental energy harvesting, intelligent robotics, and smart infrastructure. Finally, we discuss critical challenges, including stability, durability, and scalability, and outline future research directions, aiming to provide insights for the ongoing development and practical implementation of highly efficient, self-powered systems.