Demonstration of electrochromism in copper oxide thin films prepared via spray pyrolysis

Abstract

Electrochromism in copper oxide thin films deposited using spray pyrolysis technique was successfully demonstrated at 5 V and 10 mA. Cathodic and anodic reactions result to reversible transition between copper oxide and copper. XRD patterns confirm the presence of both CuO and Cu₂O on the fabricated films and even after electrochemical cycling supporting the reversible switching behavior. The electrochromic efficiency of the system measures 1.2 cm²/C at 1000 nm. High transmittance modulation was observed in the NIR region which ranges from 19% to 71% at 1000 nm. The reflectance modulation covers up to approximately 50% difference between the two optical states (Cu_xO and Cu) at 1000 nm.