The electrochromic WO3-x and Ni1-yO are n-type and p-type semiconductors, respectively. Due to the defect-driven insulator-metal-transition upon ionic insertion/extraction, the electrical conductivity can be tuned in a wide range, along with their electrochromic behavior, using electrolyte gating. The electrical conductivity closely associated with defect concentrations enables us to selectively control conductivities in WO3-x and Ni1-yO thin films and obtain specific electrical properties by appropriate modification of the stoichiometry. The electrical conductivity is dynamically varied via electrolyte gating. The electrolyte-gating-induced changes in electrical conductivity, as well as lattice dimensions, are reversible through multiple electrochemical cycles. These findings not only expand the basic understanding of charge carrier transport in complex oxides but also provide a path to dynamically control the electrical conductivity. In our work, the ionic-gated optical, electrical, and electrochemical properties are systematically investigated in electrochromics. The colorimetric response and electronic conductivity could be switched reversibly and dynamically by exploiting the substantially different charge of oxidized and reduced WO3-x and Ni1-yO, leading to redox-controllable ion gating optical, electrical, and electrochemical properties. The redox-switchable electrochromic films along with interesting electrical insulator-metal transition properties may find potential application in electronic smart devices, biosensors, and energy conversion systems.

Ionic-gating electrochromic thin solid films WO3-x and Ni1-yO: Optical transparency, electrical conductivity, and electrochemical impedance

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.