Reversible Coloration Enhanced by Electrochemical Deposition of an Ultrathin Zinc Layer onto an Anodic Nanoporous Alumina Layer

A productive method is introduced to realize large area color electronic paper (e-paper) with high UV resistance, heat resistance, and good significant bending properties using a color change triggered by reversible electronic change in the device structure. Reversible coloration and decoloration triggered by electrochemical deposition and desorption, respectively, of an ultra-thin zinc (Zn) layer on a thin transparent conductive layer coated on anodic nanoporous alumina has been developed. The deposition of the ultra-thin Zn layer triggers the formation of destructive interference, which leads to coloration. Yellow, magenta, and cyan colors were obtained in the colored state by increasing the NP-Al2O3 layer thickness, based on Bragg diffraction theory. Reflectance of more than 70% and contrast values of more than 7 were obtained, which are nearly equivalent to those of previous e-papers. The color images in these devices also showed high UV resistance, heat resistance, and repeated significant bending endurance. The devices can be fabricated with large areas using low-cost manufacturing processes such as anodic oxidation, and use abundantly available materials. Our proposed device provides low-cost and flexible large area color e-paper for outdoor use.