Manipulating the optical and electronic properties of MoO3 films through electric-field-induced ion migration

Abstract

MoO₃ films with a (0k0) orientation were deposited by pulsed laser deposition on a glass substrate and lithium conducting ceramic substrate. Hydrogen or lithium evolution was realized in the MoO₃ thin films by ionic liquid gating due to the existence of hydrogen ions and lithium ions in the ionic liquid and the substrate, respectively. The intercalation of hydrogen ions or lithium ions causes the reduction of the Mo element and the resultant transformation of the electronic and optical properties of the MoO₃ films. A nearly five orders of magnitude modulation of the MoO₃ conductivity is obtained. And the pristine transparent film is changed to blue. Thus, the migration of ions driven by the ionic liquid gating can trigger the reduction of Mo in the MoO₃ films, resulting in a large change in the electronic and optical properties. This study shows potential in the field of the emulation of the artificial synapses, and can supply a novel method for designing multifunctional devices.