Low-Temperature Deposition of Transparent Conducting Films Applied to Flexible Electrochromic Devices

Here, we compare two different transparent conducting oxides (TCOs), namely indium tin oxide (ITO) and indium zinc tin oxide (IZTO), fabricated as transparent conducting films using processes that require different temperatures. ITO and IZTO films were prepared at 230 °C and at room temperature, respectively, on glass and polyethylene terephthalate (PET) substrates using reactive magnetron sputtering. Electrochromic WO₃ films deposited on ITO-based and IZTO-based ECDs using vacuum cathodic arc plasma (CAP) were investigated. IZTO-based ECDs have higher optical transmittance modulation, ΔT = 63% [from T_bleaching (90.01%) to T_coloration (28.51%)], than ITO-based ECDs, ΔT = 59%. ECDs consisted of a working electrochromic electrode (WO₃/IZTO/PET) and a counter-electrode (Pt mesh) in a 0.2 M LiClO₄/perchlorate (LiClO₄/PC) liquid electrolyte solution with an active area of 3 cm × 4 cm a calculated bleaching time t_c of 21.01 s and a coloration time t_b of 4.7 s with varying potential from -1.3 V (coloration potential, V_c) to 0.3 V (bleaching potential, V_b).