Microfabrication and electrochemical behaviors of single microcrystal of copper-doped sodium chloride solid solution

Abstract

Understanding the single-particle level of electrochemical processes taking place at the electrode/electrolyte interface is crucial for the rational development of high-performance and sustainable electrochemical microdevices. Based on scanning electrochemical cell microscope (SECCM) technology, copper-doped sodium chloride solid solution microcrystal was prepared in-situ and assembled into microdevices. In the process of synthesizing copper-doped sodium chloride solid solution, the redox behavior of Cu(II)-Cl system in the microelectrochemical cell was studied. The CV curve showed that the microdroplet contact between the microtubule and substrate was supersaturated, confirming the thin layer electrochemical response characteristics. By constructing the microcrystal between 2.5 µm spaced gold electrode pairs, the "solid" redox behavior of a single copper-doped sodium chloride microcrystal in the absence of electrolyte was studied. It is found that there is a well-resolved transformation between Cu(0), Cu(I) and Cu(II) in the microcrystal. It should be noted that the adsorbed water provides H+as a pair of ions, which plays an important role in the whole system. With the continuous progress of potential scanning, the solid-state CV curves of microcrystals gradually show semiconductor characteristics. This work presented herein is expected to promote the production of practical materials by SECCM and the practical application of on-site construction of electrochemical microsystem into all solid-state microdevices.