Raw hibiscus extract as redox active biomaterial for novel herbal electrochromic device

Abstract

A novel herbal electrochromic device has been fabricated using raw hibiscus flower extract and its performance parameters have been studied. With no usage of any chemical to obtain extracts of herbal hibiscus flower is in itself a safe, economic way and a first such demonstration. Optical and electrochemical properties of the herbal extract have been studied using optical absorption and photoluminescence spectroscopies. The Cyclic Voltammetry curves of the extracted solution shows reversible redox activity with overall reducing behaviour corresponding to less than a volt. The redox induced color switching properties of the solution is studied by monitoring the spectral changes in its as-prepared and chemically reduced forms. The color change, when mimicked using dynamic doping, can also be achieved to form a solid state electrochromic device. Performance of such a fabricated device has been studied in terms of its color modulation, switching speed and cyclability. This demonstrates the first herbal electrochromic device using natural ingredients which leads the way to have better performing sustainable and environment friendly devices. © 2020 Elsevier B.V.