IZO deposition by RF and DC sputtering on paper and application on flexible electrochromic devices

• We deposited IZO by DC Sputtering on heat sensitive substrates such as paper.
• The materials displayed high electric conductivity and optical transparency.
• Electrochromic materials were deposited using screen-printing.
• Solid-state electrochromic devices were assembled, showing an excellent performance.

The present work describes indium-zinc oxide (IZO) sputtering depositions onto several types of papers, using radio-frequency (RF) and direct current (DC) sputtering with a ceramic IZO target. The electrical and optical properties of the resulting materials were optimized; by studying the argon and oxygen gas flow rates and the sputtering power effects. At optimal deposition conditions, thin films of IZO were achieved with a low sheet resistance (about 20 Ω/sq) and an optical transmittance of ca. 80% in the visible spectrum range. These materials retained these properties for more than 8 months. Electrochromic devices (ECDs) with several configurations were built with those conductive papers and life cycling and contrast were measured for the ECDs. These devices exhibited a very good color contrast (as defined using L*a*b* color coordinates, = 32) and electrochromic cyclability up to 30,000 redox cycles.