Silver Electrodeposition Based Multicolor Electrochromic Cell Toward Energy Saving Applications

Electrochromism (EC) is defined as a reversible color change by electrochemical redox reaction and has several features such as color variation, memory property and so on. Multifunctional electrochromic materials which control multiple colors, various color density, and specular reflection are expected to be potential candidate for light-modulation device such as smart window and novel reflective display device such as e-paper. Electrodeposition is an attractive method to create colors because silver (Ag) nanoparticles exhibit various optical states based on their localized surface plasmon resonance (LSPR). LSPR bands of metal nanoparticles are affected by the size and shape. The control of LSPR, therefore, must enable dramatic changes in color for the surface where nanoparticles are deposited. We successfully demonstrate the first LSPR-based multicolor EC device enabling reversible control of six optical states such as transparent, silver mirror, cyan, magenta, yellow and black, which is attractive for smart window as well as color e-paper application. We will discuss the mechanism of electrodeposition and a wide range of its applications.