Preparation and electrochromic properties of polyethylene oxide intercalated Vanadium pentoxide composite films and devices

Abstract

A stable and efficient composite electrochromic material, Vanadium Pentoxide combined with polyethylene oxide (V₂O₅-PEO), was exhibited using an Electrophoretic Deposition (EPD) technique. The interlayer spacing of V₂O₅ was adjusted by the PEO component during electrophoretic adsorption, allowing for rapid ion exchange, with overall conductivity being enhanced and electrolyte penetration being accelerated. The elemental composition of the films was analyzed via X-ray Photoelectron Spectroscopy (XPS). A higher relative content of V⁴⁺ was observed in the green and blue states, while V⁵⁺ was predominant in the orange state. An electrochromic device (ECD) was assembled using V₂O₅-PEO as the active electrochromic layer. Multicolor performance was demonstrated by the device, with transitions observed between yellow, yellow-green, green, blue-green, orange, and various intermediate shades. Due to the moderate increase in the interlayer spacing of the film, the ionic migration ability was enhanced, with a balance achieved between the conductivity and ion exchange capability of PEO. Outstanding electrochromic performance was exhibited by the V₂O₅-0.5PEO device, including a rapid response time (3 s for coloration and 1.5 s for bleaching at 796 nm), high optical contrast (ΔT = 40 % at 796 nm), and a significant coloration efficiency (CE = 38.3 cm2/C).