An All Solid State Electrochromic Device Based On A Eutectic Solvent

Electrochromic material is a promising functional material,which in a large display,light switch,non glare mirror,electrochromic devices and storage building glass and smart windows have broad application prospects.However,in order to promote the practical application of electrochromic materials,all solid state electrochromic devices must be prepared.The electrochromic device includes at least one electrolyte layer and two electrodes.The electrolyte layer provides free ions allowing current flow between two electrodes.Usually these ions come from the salt dissolved in the solvent.In the category of green chemistry,solvent occupies a crucial position.As a green medium must meet the following conditions: raw materials easy to get,no toxicity,low cost and biodegradable.Ionic liquids have the advantages of low vapor pressure,non flammability,good conductivity and solubility,stable chemical properties and zero saturation vapor pressure,but they have some problems such as complex synthesis and high production cost.Therefore,it is necessary to develop a kind of solvent which can combine the excellent physical and chemical properties of ionic liquids with degradable materials.Therefore,the eutectic solvent quickly into the line of sight,it is from two to three low cost,non-toxic substances through hydrogen bonding,and the melting point is lower than any of the components.Compared with ionic liquids,the eutectic solvents have similar physicochemical properties,and are more environmentally friendly and easy to obtain.It is possible to improve the overall performance of electrochromic devices by the application of eutectic solvent or eutectic solvent gel electrolyte.Chemically modified electrodes have been the subject of research in the field of electrochemistry and electroanalytical chemistry since 70 s.At present,it has been widely used in many fields,such as life science,environmental science,analytical science,material science and so on.The surface modified media can accelerate the rate of redox electron transfer of the tested material to achieve the electrocatalytic reaction.Due to the small particle size,nano materials have a lot of specificity,because of its good biological compatibility and excellent catalytic performance,nano gold has become one of the most widely used nanomaterials in recent years.In this paper,the preparation of electrochromic devices using gold nanoparticles asmodified FTO electrode.The electrochromic materials ethyl viologen and electron donor ferrocyanide soluble choline chloride glycol eutectic solvent system as the electrolyte layer,FTO as the two electrode preparation liquid electrochromic device.The solid state devices were obtained by the nano silica gel method,and the potential step method was used to deposit the gold nanoparticles on the surface of the FTO electrode,so as to obtain the nano gold modified electrochromic devices.The results show that when the weight ratio of hydrophilic nano silica and low eutectic solvent is 10%,the transparent gel with a conductivity of 8.5×10-3 S / cm-1 is obtained.The preparation method of the gel electrochromic devices in the eyes of the most sensitive wavelength of 550 nm has the maximum coloration efficiency is128cm2·C-1,the maximum working voltage of 0.8V devices.After the gold nanoparticles modified gel electro optimum voltage electrochromic device can reduce the 0.1V of the device,low power consumption,low cost,simple structure.