Electrochromic Device Demonstrator from Household Materials

Abstract

Electrochromism encompasses reversible changes of material's optical properties (color, opacity) under the influence of an external electric current or applied voltage. The effect has been known for decades, but its importance continues to grow due to the rapid development of smart systems and the accompanying demand to build devices that consume less power. Most commercial electrochromic devices (ECDs) require sophisticated chemicals and advanced material preparation techniques. Also, the demonstration of electrochromism in chemistry classes mainly uses expensive WO 3 films, intrinsically conductive polymers, and/or optically transparent electrodes (OTEs). The aim of this article is to present a simple and fast educational method to build ECDs from household materials without the need for OTEs: unsharpened kitchen knives are used as electrodes, curcumin from turmeric is used as the electrochromic dye, and baking soda is used as the electrolyte. The laboratory experiments presented will help students gain a deeper understanding of the fundamentals of electrochemistry (electrolysis, pH change) and electrochromism (in our case, color changes due to pH-induced keto-enol tautomerism of curcumin).

Flexing the Spectrum: Advancements and Prospects of Flexible Electrochromic Materials

“…Type II ECDs fall between type I and type III. In type II devices, only the bleached component is dissolved in the electrolyte, while the colored component forms a coating on one of the electrodes [12,13].…”

“…Dual-band electrochromic devices have unique characteristics, such as bistability, low power consumption, and separate control over the The classification of electrochromic devices (ECDs) is based on the solubility of the bleached and colored electrochromic components in the electrolyte layer. There are three types of ECDs: type I, II, and III [1,12,13] (Figure 2). Type I devices are characterized by the fact that both components are soluble in the electrolyte during operation.…”