Switchable Silver Mirror Window without Bromide Ion

摘要

The reversible electrochemical switching mirrors between mirror state and transparent state using silver bromide ion complex have been greatly investigated for application to smart windows and mirrors. There are some advantages to reflect light and not to absorb one in the high reflective silver metal state from the viewpoint of the thermal management. However, there are also some drawbacks to use bromide ion. Silver bromide ion complex is poor solubility in the common solvents, which also required strong polar solvents such as DMSO. In addition, the silver bromide ion complex is light-sensitive and not suitable for many applications. Moreover, Br_3~- ion as the redox couple of Br~- ion has absorption in the visible wavelength region. Therefore, it was important to find the other systems where Ag may be deposited in a mirror form without the use of bromide ion. In the previous study, a mixed solvent of ionic liquid and acetonitrile has been employed instead of DMSO and silver bromide was not used. This novel reversible silver switching mirror window system is quite simple, stable and safe because the materials used in this system are citric acid as the electrolyte additive and Pd nanoparticles (NPs) as the catalyst which are plated as nuclei on the ITO electrode for facilitating Ag plating and dissolution. In this study, the non-bromide ion switchable silver mirror window was prepared and its performance was investigated.