Surface Contact Electrification Effects of Liquid Metals for Atomic-Level Functional Transformation Under Ambient Conditions

Abstract

Gallium oxyhydroxide (GaOOH), a multifunctional material existing in diverse morphologies such as nanowires and nanosheets, holds great potential for optoelectronic applications due to its distinct phase structures, adjustable band gaps, and facile solution doping. However, its synthesis has been hindered by the need for complex reaction conditions and limited reaction spaces. The gallium-based liquid metals (LMs) remain liquid state at room temperature and exhibit exceptional surface mechanoelectrochemical activity. It is highly sensitive to foreign substances, allowing for the adjustment of reaction products based on composition and environmental factors, thus providing a promising approach for synthesis of GaOOH. Herein, a solution-processable strategy for synthesizing and modifying nanostructured GaOOH (nano-GaOOH) using LMs at room temperature. Nano-GaOOH isdirectly synthesized bthrough the reaction of GaIn with deionized water, and its structure and properties are adjusted by interfacial friction. Copper (Cu) doping in liquid metals induces surface friction via mechanical stimulation, creating a high electric field region that promotes the electrochemical synthesis of Cu-GaOOH. This doping enhances nano-GaOOH production, induces a morphological transition from nanowires to nanosheets, and enables bandgap tuning. This study offers an efficient, controllable, scalable, and environmentally friendly approach for GaOOH manufacturing.

Keywords: Liquid metals, Contact electrification, Semiconductor materials, Solution-processable method, Mechanochemical activity