Iontrovoltaic effect based on triboelectrically induced ion polarization at semiconductor-liquid interfaces

Abstract

Controlling interfacial energy levels at semiconductor-liquid interfaces is critical yet challenging because charge separation is dictated by coupled semiconductor band bending and electrical double layers. Existing chemical and electrical regulation strategies inevitably require invasive treatments or external energy input. Here, we propose an iontrovoltaic mechanism, in which asymmetric electrical double layers establish ionic concentration gradients driving ionic directional migration. Triboelectrically induced ionic polarization simultaneously modulates electrical double layers and semiconductor band bending, enhancing the coupled electrical double layer-space charge region field to promote photocarrier separation. Coupled interfacial oxidation and ionic migration enable efficient ionic-electronic transport in iontrovoltaic nanogenerators. Local pH mapping, Kelvin probe measurements, and Mott-Schottky analysis confirm coupled ionic redistribution and band modulation. Integrating alkaline oxidation and infrared photothermal activation yields redox-coupled iontrovoltaic nanogenerators with a peak power density of 541 W m−2, exceeding representative triboelectric, tribovoltaic, and triboiontronic systems. By coupling dynamic electrical double layer programming with semiconductor band modulation, iontrovoltaic effect establishes interfacial electrostatics as an active driver of energy conversion and ionic transport, opening opportunities for autonomous, low-power ionic-electronic systems. This work introduces an iontrovoltaic effect that enables efficient energy conversion at semiconductor-liquid interfaces through coupling of triboelectric polarization, electrical double layers, and band modulation.