[Paper] Electrochemical Morphology Control of Silver Nanoparticles in Silver Deposition-Based Electrochromic Devices Employing a Derivative of Ethylenediaminetetraacetic Acid

Silver nanoparticles (AgNPs) can exhibit various chromatic colorations depending on their morphology. This study utilized a derivative of ethylenediaminetetraacetic acid (EDTA) to control the electrodeposited morphology of AgNPs in an Ag deposition-based electrochromic (EC) device. Because the carboxyl groups of the EDTA derivative were electrochemically reduced to radical anion and worked as an electrochemical mediator, the deposition of AgNPs was promoted. As a result, the morphology of deposited AgNPs formed an anisotropic shape, such as a rod or needle, due to the mediation effect of the EDTA derivative. Moreover, the EC device with EDTA derivative exhibited a deep black state since AgNPs were formed as porous structures, inducing multiple scattering. Consequently, a black state on a flat electrode with less than 20% reflection was achieved without the ITO nanoparticles-modified electrode.