Mechanism of Optical Reflectance Enhancement on Ag Electrodeposition-based Electrochromic Cells by Introduction of Citric Acid

Abstract

A citric acid was added to the electrolyte as an capping agent to effectively enhance the reflectance of the Ag deposition-based electrochromic (EC) cells. The electrochemical properties of EC electrolytes containing different concentrations of citric acid were compared and the surface morphology of Ag deposited in these electrolytes were also analyzed. The redox potential of Ag+/Ag was not changed in the presence of citric acid, but the rate of consumption of Ag+ in the deposition was significantly affected by the citric acid especially in case of high concentration. As adding citric acid, the increasing of reflectance of Ag deposits in total wavelength region is increased, typical at the [Silver nitrate] : [Citric acid] is 1 : 2, the reflectance in the wavelength range (400–580 nm) is increased more, it is leading to specular mirror appearance. The mechanism for enhancement of the reflectance was discussed in terms of surface morphology of the Ag deposits and deposition behavior of the Ag nanoparticle.

Keywords

• silver
• reflectance enhancement
• electrochromism
• citric acid