Utilizing rare earth titanates to improve performance of solid-state electrochromic device

Abstract

Exploring new materials and synthesis recipes are required to enhance the electrochromic performance especially when used in solid-state devices. Here polycrystalline gadolinium titanate (Gd2TiO5 or GTO), synthesized using a simple solid-state reaction method, has been used for this purpose by combining it with polythiophene (P3HT). The electrochemical investigation of Gd2TiO5 doped P3HT electrode has been carried out using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) which reveals the dominance of diffusion-controlled mechanism over charge storage on the electrode surface as compared to the P3HT electrode. The Gd2TiO5 doped P3HT solid-state electrochromic device shows color modulation at 515 nm and 670 nm wavelengths with color contrast of as high as 79% and 42%, respectively, under the external bias of as low as ± 1.4 V. The prepared device switches between maroon to transparent state in less than a second under the external bias (± 1.4 V) with a high coloration efficiency of 346 cm2/C. The device shows improved cycle life over 100 switching cycles at both the wavelengths, which makes it more suitable for real-life applications.