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[EN] Electrochromic devices (ECDs) have the ability to selectively change color under the influence of electric current or potential and can keep the selected color after disconnection. They are used as smart windows, e-ink displays and even as flexible tapes. Most multicolor ECDs incorporate traditional “sandwich” architecture, which requires at least one electrode to be made of a transparent conductive polymer or thin film ceramics, and can be quite fragile and sensitive. In this paper, a flexible and durable multicolor ECD tape is reported, which uses advanced architecture, steel foil electrodes, and multiple coloration systems, for example intercalation used in tungsten and vanadium oxide based electrochromic systems, as well as a redox dye, for example methyl orange. The presented ECD tapes can utilize different metal oxides and color mechanisms with coloration efficiency around 10 cm2 C−1 for V2O5 and WO3 in both visible and IR range, and more than 30 cm2 C−1 for ZnO with added methyl orange dye. Due to the use of stainless-steel foil as a substrate, the assembled ECD tape has excellent durability properties, withstanding more than 39 MPa of pressure, and could therefore be used even in the most adverse conditions, for applications such as adaptive camouflage, color changing clothes, or other applications

[EN] Electrochromic devices (ECDs) have the ability to show color even when electrical power is disconnected. However, challenges such as simple and cost-effective electrochromic material preparation, insufficient coloration, slow switching times, and poor cycling stability have yet to be overcome. The paper describes an electrochromic device with WO3 thin film as the electrochromic material for the working electrode and ZnO thin film as a counter electrode fabricated on FTO glass substrates by a simple sol–gel spin coating method. The optical contrast at 600 nm of ZnO counter electrode based ECD (12.4%) is almost double that of graphite counter electrode based ECD (6.5%), showing higher efficiency and better electrochromic response. The properties of ECD devices were also examined using cyclic voltammetry and chronoamperometry measurements with results showing that the devices were stable and the charge required to tint the device (5.6 mA s) is reduced compared to typical graphite-coated counter electrode. These types of devices are promissing candidates to be used as smart windows., [ES] Los dispositivos electrocrómicos (ECD) tienen la capacidad de mostrar color incluso cuando se desconectan de la energía eléctrica. Sin embargo, para su implantación total deben superarse importantes desafíos como la preparación de materiales electrocrómicos simples y rentables, la coloración insuficiente, los tiempos de conmutación que son lentos y la mala estabilidad del ciclo. En este artículo se describe la preparación de un dispositivo electrocrómico basado en una película delgada de WO3 como electrodo de trabajo y una película delgada de ZnO obtenida por sol-gel como contra-electrodo, todo fabricado sobre sustratos de vidrio FTO mediante un método simple de centrifugado. Como resultados destacar que el contraste óptico a 600 nm del ECD basado en el contra-electrodo de ZnO (12,4%) es casi el doble que el del sistema ECD basado en el contra-electro de grafito (6,5%), mostrando una mayor eficiencia y una mejor respuesta electrocrómica. Las propiedades del dispositivo ECD de ZnO también se examinaron mediante voltametría cíclica y cronoamperometría y los resultados mostraron que los dispositivos eran estables y la carga necesaria para teñir el dispositivo (5,6 mAs) se reducía comparado con el dispositivo ECD de grafito. Este tipo de dispositivos son candidatos prometedores para ser utilizados como ventanas inteligentes.