Preparation Of Ferrocence-based Colloidal Crystal Films And Their Electrochromic Properties

Electrochromic materials can change their optical parameters persistently and reversibly during external electric field stimulation.Because of stable and reversible optical property and high energy density,they are widely used in smart windows,monitors and other fields.Since discovered in 1951,ferrocene and its derivatives have been widely used in the fields of electrochemistry and photoelectricity due to their special structure and excellent electrochemical properties.In this dissertation,we designed ferrocene derivatives electrochromic mat erials with different morphological through the environment friendly and ener gy efficient method,including layers of P?St-MMA-AA?/Fc?COCH₃?₂,SiO₂/Fc?COCH₃?₂,SiO₂/Fc?COOH?₂,SiO₂/Fc?CH₂?₂,SiO₂/Fc?CH?₂,SiO₂@Fc?COCH₃?₂and monolayer Fc?COCH₃?₂ films.We prepared ferrocene-based colloidal cryst als materials by colloidal crystal self-assembly method.The electrochromic pr ocesses of these materials were systemtically investigated,and the relationship between electrochromic properies and nanostructure were discussed and analy zed.The main research works are as follows:P?St-MMA-AA?colloidal crystal microstructure was introduced into Fc?COCH₃?₂ assisted by self-assembly method.Compared with dense Fc?COCH₃?₂film,electrochemical activity?transmittance change and cycle stability of layers of P?St-MMA-AA?/Fc?COCH₃?₂ were markedly improved.Due to the collapse of P?St-MMA-AA?nanosphere's soft shell,Fc?COCH₃?₂ paricles can form aggregation easily on the spheres's surface,thus affecting its electrochromic properties.The rigid SiO₂ nanostructure was introduced to the ferrocene derivatives which have different functional groups.They were fabricted using a solvent evaporation self-assembly method to fabricate layers of SiO₂/Fc?COCH₃?₂,SiO₂/Fc?COOH?₂,SiO₂/Fc?CH₂?₂,SiO₂/Fc?CH?₂ films.Cyclic voltammograms curves,transmittance change and cycle stability of the films were tested and compared.For layers of SiO₂/Fc?COCH₃?₂ film with different Fc?COCH₃?₂ volume,the higher reflectivity,aflorded greater electrochemical activity.The SiO₂ nanostructure significantly shortened the response time,and the transmittance change and cycle stability are greatly improved.This means that the ordered degree of SiO₂ nanospheres is related to the electrochemical and electrochromic properties of SiO₂/Fc?COCH₃?₂ film.If was complained that the higher ordered degree of the nanospheres,give rise to the more uniform Fc?COCH₃?₂,and thus stronger the more sufficient contact between the active substance and the electrolyte,resulting in better electrochemical and electrochromic properties.But the result for SiO₂/Fc?COOH?₂,SiO₂/Fc?CH₂?₂ and SiO₂/Fc?CH?₂ films,fall to demonstrate the same trend.Core-shell SiO₂@Fc?COCH₃?₂ nanospheres were fabricated using ultrasonic assisted chemical bath deposition method.Then layers of SiO₂@Fc?COCH₃?₂ films with different prosity systems were self-assembled on ITO substrate through the controll self-assembly method.The relationship between the order degree and electrochromic properties were systematicly studied.By controlling the self-assembly conditions,the quasi-amorphous/ordered porous SiO₂@Fc?COCH₃?₂film were fabricated,and then the electrochromic performance were compared.At550 nm,the transmittance change of quasi-amorphous ordered porous SiO₂@Fc?COCH₃?₂ film changes by 19.1%,the ordered porous SiO₂@Fc?COCH₃?₂film by 34.4%.The coloration efficiency for quasi-amorphous ordered porous SiO₂@Fc?COCH₃?₂ film is 30.58 C^-1 cm²,and 48.6 C^-1 cm² for the ordered porous SiO₂@Fc?COCH₃?₂ film.The coloration and bleaching times for quasi-amorphous film is 17.1 and 4.5 s,whereas it is 16.5 and 3.5 s for the ordered porous SiO₂@Fc?COCH₃?₂ film.Monolayer SiO₂/Fc?COCH₃?₂ films were prepared by a sol-gel method at room temperature.SiO₂ monolayer colloidal crystal?MCCTs?was used as templates.The structure,optical and electrochemical properties of monolayer SiO₂/Fc?COCH₃?₂film were tested and compared with compact Fc?COCH₃?₂ films to evaluate the role of the nanoarchitecture.Such a nanostructure exhibit unique electrochemical properties:the MCCTs could impede the aggregation of Fc?COCH₃?₂ and thus possess high electrochemical activity.The MCCTs enlarges the contacting area and offers more active sites and faster electronic transmission channels.The unique structure design monolayer Fc?COCH₃?₂ film outstanding performance,showing large transmittance change of 38.7%at 550 nm,which is approximately 6.5-fold higher than that of dense Fc?COCH₃?₂ film?approximately 6.1%?.The coloration efficiency for dense Fc?COCH₃?₂ film is 17.08 C^-1 cm²,56.81 C^-1 cm² for monolayer SiO₂/Fc?COCH₃?₂ film.Response times of coloration and bleaching for monolayer SiO₂/Fc?COCH₃?₂ film are found to be as short as 15.3s and 4.0s.