Electrochromic performance of reactive plasma-sputtered NiOx thin films on flexible PET/ITO substrates for flexible electrochromic devices

Electrochromic properties of NiOx (nickel oxide) thin films sputtered on 40 Omega/square flexible PET (polyethylene terephthalate)/ITO (indium tin oxide) substrates were investigated. Metallic Ni target, sputtered by radio frequency (r.f.) power with argon gases and reacted with oxygen gases at room temperature (23 degrees C), was proven to provide significant electrochromic properties. Cyclic voltammetry switching measurements found that only low driving voltages from -0.6 V to 1 V were needed to provide reversible Li+ ion intercalation and deintercalation. Light modulation with up to 40% of transmittance variation, optical density change of 0.354 and color efficiency of 67 cm(2)/C at a wavelength of 550 nm were obtained for 1100 cycles of Li+ intercalation and deintercalation in a 1 M LiClO4-PC (propylene carbonate) electrolyte. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.