Liquid-phase exfoliation of two-dimensional siloxene via two-step interlayer expansion process

Abstract

Two-dimensional (2D) materials which are produced by exfoliating layered materials show unique and distinct properties compared with their bulk counterpart. Surface functionality of the 2D materials can endow these materials with various solution-based processabilities. Siloxene is a kind of 2D materials mainly composed of silicon and oxygen. This material has drawn big attention as a candidate for energy storage materials such as supercapacitors, secondary batteries, and electrochemical catalysts owing to its compatibility with Si-based electronics, tunable electrical properties, and semiconducting characteristics. However, most of the siloxenes which have been utilized in various research area until nowadays are multilayered structure due to the limitations of conventional exfoliation methods of this material. In this study, pure siloxene is exfoliated in a short time by introducing two-step interlayer expansion method. Through the first step, siloxene which is synthesized by copper chloride shows expanded structure owing to intercalation of copper nanoparticles. By exploiting ion exchange method as second step, the interlayer expanded siloxene is successfully exfoliated. The effectiveness of this exfoliation method is investigated by comparing it with other conventional ones. In addition, free-standing siloxene films and siloxene thin-films are fabricated and characterized by utilizing exfoliated siloxene. This work shows the possibility to applying various solution processes into siloxene to fabricate siloxene macro/nanostructures and composites.