Evaluation of low-voltage-driven multi-colored electrochromic device based on dry-deposited V2O5

Abstract

A V2O5 film fabricated by a nanoparticle deposition system (NPDS) was used to demonstrate a highly durable electrochromic device (ECD). The V2O5 film deposited on both the electrodes functioned as a complementary layer during the redox reaction to balance the charge inside the device. Thereby, it mitigated the load applied to the ECD by enabling its electrochromic reaction within the range of ±1 V. The fabricated ECD showing different colors at opposite voltages were applied to both the electrodes. Meanwhile, a TiO2-based opaque electrolyte was used to show different colors of V2O5 thin films independently. The fabricated ECD can display three colors: yellow, green, and blue. Furthermore, each color variation is completed within 10 s. According to the International Commission on Illumination (CIE) data, the color differences (ΔE) between yellow and green, green and blue, and yellow and blue were measured to be approximately 27, 17, and 44, respectively. Meanwhile, the fabricated ECD showed almost a similar level of electrochromic performance even after 500 repeated runs. Moreover, the charge capacity of the ECD after a 10,000-cycle cyclic voltammetry (CV) analysis was 49.01 mC/cm2 (the initial charge capacity was measured to be 47.31 mC/cm2). This verified the high durability of the device. Thus, an ECD capable of coloration under a low voltage range of ±1 V was fabricated using a dry deposition method with a TiO2-based opaque electrolyte, to vividly display different colors at both sides of the device simultaneously. The unique device can independently display different colors on both the electrodes. The dry deposition method was applied to deposit an identical V2O5 electrochromic film on the electrodes and an opaque electrolyte. The device has potential applications in functional electrochromic displays.