Research On The Preparation And Performance Of Silver Electrodeposition-based Electrochromic Devices

In the electrochromic industry,the reversible metal electrodeposition device,as a novel electrochromic device,is an underexplored method.Metal Ag electrodeposition-based electrochromic devices（abbreviated as reversible Ag-based electrodeposition device,RAg ED）have received widespread attention,since its electrolyte’s high transparency and mirror state adjustment function.The different effects appear on the tristate RAg ED,such as the Ag particles are deposited on smooth electrode tend to be mirror-like and the Ag particles are deposited rough electrode tend to be black.Oxide species that mediate the dissolution of Ag are introduceed into the electrolyte of traditional RAg ED,which leads to serious self-erasing phenomenon.After the device is powered-off,it needs to be continuously powered to maintain the coloring state,which increases energy consumption,limiting its application.To solve this problem,the TiO₂ nanorod array（TiO₂ NRA）prepared by the hydrothermal method,as the ion storage layer,was combined with reversible Ag-based electrodeposition to construct a tandem adjustable Ag mirror device.The device can maintain the Ag mirror state for a long time under open-circuit state due to avoid the introduction of oxide species.In addition,the black state effect is realized by the local surface plasmon resonance effect,and it is closely related to the morphology of Ag nanoparticles.The morphology of Ag nanoparticles is heavily dependent on the electrode with a rough surface.Therefor,the TiO₂ NRA was also used as a rough electrode combined with smooth ITO（Tin-doped Indium Oxide）electrode to construct a RAg ED that can realize tristate of transparent,black and mirror.This device possess high ability of optical modulation.The specific research content of the paper is as follows:（1）TiO₂ NRA were grown on FTO（fluorine-doped tin oxide）by hydrothermal synthesis.By controlling the hydrothermal growth time,the three kinds of TiO₂NRA with different density were prepared.The three kinds of TiO₂ NRA showed high optical transparency,and the TiO₂ NRA prepared by hydrothermal growth time of 4 h showed the largest charge storage capacity and the highest electrochemical reaction reversibility.（2）The TiO₂ NRA prepared by the hydrothermal growth time of 4 h was connected with reversible Ag electrodeposition to construct a tandem adjustable Ag mirror device.The transmittance of this device remained below 50%of the initial state within 600 s of power-off,indicating that this device was relatively stable in the open-circuit state.This device showed excellent cycling stability,the transmittance change attenuated from 69%to 59%after 1000 cycles.（3）Three kinds of TiO₂ NRA with different density were used as the rough electrode layer combined with reversible Ag electrodeposition to construct the tristate RAg ED.These devices showed excellent capability of optical modulation.With the density of the selected rods increasing successively,the transmittance of transparent state of the device at the wavelength of 700 nm was 83.3%,75.8%,and73.7%,respectively,and the corresponding transmittance of the black state was2.0%,1.5%and 1.4%,respectively;the black reflectance at the wavelength of 600nm all were 5.8%,and the specular reflectance was 76.0%,72.4%and 69.7%,respectively.