A concise and efficient solution method for the preparation of high performance electrochromic peryleneimide derivative/Cu2O hybrid films

Abstract

The preparation of high-performance films through a simple and low-cost route has been one of the goals pursued in the field of electrochromism (EC). As a common n-type organic dye, perylimide derivatives have been attracting attention due to their advantages such as multi-colors change, fast switch time and high optical contrast. However, their inferior solubility and stability limit the wide application of these compounds. In this work, the hybridized films of PDI-COOH Cu₂O@ and PCl-COOH Cu₂O@ were obtained using a simple solution method by immersing the Cu₂O films obtained via electrodeposition in water-soluble perylimide derivatives PDI-COOH and PCl-COOH. The ligand-metal binding via coordination bond and intermolecular π-π stacking were determined by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM). Besides, the two films exhibited reversible redox activity and cathodic electrochromic properties from pink to purple (-0.7 V). Notably, the PDI-COOHCu₂O@ hybrid films show faster switching time (6.29 s for coloring and 4.94 s for bleaching), better stability (93.63 %) contrast retention after 1800 cycles), lower driving voltage (-0.7 V∼0.4 V) and higher coloring efficiency (271.18 cm²/C). This method of constructing organic-inorganic hybrid electrochromic materials using coordination bonds provides an effective strategy to facilitate the large-scale and low-cost production of functional thin films. The method to construct organic-inorganic hybrid electrochromic materials using coordination bonds provides an effective and convenient strategy to facilitate the large-scale and low-cost production of functional films.