Oxygen and temperature effects on the electrochemical and electrochromic properties of rf-sputtered V2O5 thin films

Vanadium pentoxide (V2O5) thin films grown by rf-sputtering have been studied as a function of two growth parameters, O2 content and substrate temperature, which influence importantly their structural, as well as their electrochemical and electrochromic properties. The increase in O2 content appears to result in an increase of the grain size of the films, while the increase in substrate temperature leads in platelets perpendicular to the substrate, which enhance the porosity of the films. Films with low O2 content (3%) and films grown at a substrate temperature of 300 °C, present enhanced charge storage properties of 553 mA h g−1 and large transmittance modulation ability. On the contrary, high O2 content (11%) and a substrate temperature of 150 °C lead to improved coloration efficiency (at λ = 400 nm), reaching values of 84.5 and ∼132 cm2C−1, respectively. These findings are discussed in terms of structural and morphological changes occurring during the two parameters studied.