| The polythiophene-based conductive polymer is a good electrochromic material,which can realize reversible color change under the action of applied voltage,and has become the focus of current research by under its excellent electrical conductivity and good stability.Among them,poly(3,4-ethylenedioxythiophene)(PEDOT)as a p-type doped aromatic heterocyclic conductive polymer is widely used in the field of electrochromism.In this paper,the research on the in-situ electrochemical polymerization and performance of PEDOT-based composites has been carried out.With 3,4-ethylenedioxythiophene(EDOT)as the main body,polymerized PEDOT film,poly(3,4-ethylenedioxythiophene):poly(p-styrenesulfonic acid)(PEDOT:PSS)composite film,poly 3,4-ethylenedioxythiophene doped with 1-ethyl-3-Methylimidazole bis(trifluoromethylsulfonyl)lmide:poly(p-styrenesulfonic acid)(PEDOT:PSS/EMI-TFSI)composite film.The morphological structure,electrochemical performance and optical performance of the films were tested.And the electrochromic performance and stability of the film are analyzed.The preparation process and doping components are optimized.According to the optimized results,the electrochromic film with the best performance is obtained.1.PEDOT electrochromic films are polymerized in an electrolyte of lithium perchlorate(LiClO4)using in-situ electrochemical polymerization.This method is simple to operate,short in time,and easy to control.The morphology and performance of the films can be controlled by changing the deposition voltages and times.The best process parameters are 1.4 V,40 s.PEDOT films exhibit good electrochromic phenomena,and the reversible transformation from light blue to dark blue occurs during the oxidation-reduction reaction.However,the solubility of PEDOT films in the water dispersion system is poor,and the stability in a neutral state is poor.The ion diffusion coefficient is small(0.061×10-20 cm2/s),the discoloration range is small(22.412%),and the response time is long(coloring response/fading time is 3.8 s/4.1 s respectively),and the coloring efficiency is low(92.55 cm2/C).2.The PEDOT:PSS composite films are polymerized in an aqueous solution of LiClO4 doped with PSS by in-situ electrochemical polymerization method,which improves the solubility of the PEDOT films,and the prepared films are more uniform and dense.Similarly,the PEDOT:PSS composite film prepared under 1.4 V and 40 s showed the best electrochromic phenomena,and the reversible transformation from light blue to dark blue occurred during the redox reaction.The electrochemical and optical properties of the PEDOT:PSS composite films have also been improved to a certain extent,with a larger ion diffusion coefficient(0.34×10-20 cm2/s)and a wider optical contrast(39.556%).The response time is shortened(coloring response/fading time is 2 s/3.1 s respectively),and the coloring efficiency of the film is improved(122.65 cm2/C).3.The PEDOT:PSS/EMI-TFSI composite films are polymerized in LiClO4/PSS aqueous solution doped with ionic liquid by in-situ electrochemical polymerization.Compared with adding an ionic liquid to the PEDOT:PSS aqueous dispersion and then spin-coating to form a film,this method greatly shortens the preparation time,simplifies the process flow,and improves the work efficiency,and the prepared composite film does not require post-treatment.The prepared PEDOT:PSS/EMI-TFSI composite films have good electrochromic performance,electrochemical performance,optical performance,larger ion diffusion coefficient(1.38×10-20 cm2/s),and wider color Contrast ratio(43.482%),the shorter response time(coloring response/fading time is 1.2 s/2 s respectively),higher coloring efficiency(189.86 cm2/C). |
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