Controlled Preparation of Vanadium Pentoxide Films and Their Multicolor Electrochromic Properties

Vanadium pentoxide (V 2 O 5 ) films were fabricated on indium tin oxide substrates via a simple electrophoretic deposition method, with precise control over applied voltage and deposition duration. Both the electrophoretic deposition time and applied voltage are identified as key parameters in the electrophoretic deposition process. A systematic investigation was conducted to determine the optimal voltage and time for deposition of V 2 O 5 films. The uniform V 2 O 5 films with excellent multicolor electrochromic properties, such as yellow, yellow-green, green and orange-red, could be obtained when the electrophoretic deposition time was 5 min and the voltage was [Formula: see text] [Formula: see text]V. An electrochromic device based on the as-prepared V 2 O 5 film was assembled and its switching performance was evaluated. At 730[Formula: see text]nm, the coloration efficiency (CE) value of the V 2 O 5 device was 22.6[Formula: see text]cm 2 C[Formula: see text] (from green to orange-red), and the coloring and fading times of the V 2 O 5 device were 6[Formula: see text]s and 4[Formula: see text]s, respectively. The V 2 O 5 films maintained 81.79% charge transfer after 200 cyclic voltammetry (CV) measurements in the voltage range of [Formula: see text] [Formula: see text]V to 2[Formula: see text]V. This work presents a facile and green strategy for the controllable preparation of V 2 O 5 films and their devices with multicolor electrochromic behaviors.