Novel Conducting Polymers Based On PEDOT And The Corresponding Electrochromic Properties

At present, the research of conductive polymers has focused on the preparation ofconducting polymers and their electrochromic properties. Electrochemicalpolymerization has proved to be one of the most useful approaches for conductingpolymer synthesis. Poly（3,4-ethylenedioxythiophene） is the most widely applied oneamong the variety of conducting polymers. This paper mainly synthesized3,4-ethylenedioxythiophene with2,7-dibromofluorene,1,4-dibromobenzene, and1,4-dibromonaphthalene respectively using the organic synthesis method.High-quality conductive polymers were successfully prepared by the electrochemicalpolymerization of the resulting three new compounds. Electrochromic properties of thecorresponding polymers was also investigated.1. Poly（2,7-bis （2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl）-9H-fluorene）P（EDOT-FE）, a novel electrochromic material obtained from3,4-ethylenedioxythiophene （EDOT）-bis-substituted monomer fluorene （FE） inCH2Cl2solution, has a good redox activity and thermal stability. The conductivity ofthe polymer films was tested to be2.5S cm^-1. Fluorescent spectral studies indicatedthat P（EDOT-FE） with high fluorescence quantum yields of0.797and photochemicalstability was a novel green-light-emitter. Furthermore, a dual type electrochromicdevice （ECD） based on P（EDOT-FE） and poly（3,4-ethylenedioxythiophene）（PEDOT）was constructed and its electrochromic properties were investigated meanwhile. TheECD expressed high coloration efficiency, good response time and robust cycle life.2. Poly（2,7-bis-（2,3-dihydro-thieno[3,4-b][1,4]dioxin-5-yl）-benzene）, a novelelectrochromic material obtained from3,4-ethylenedioxythiophene and1,4-dibromobenzene, was prepared by electrochemical polymerization. The polymerrepresented a good electrochemical stability and high electrochromic performance. The polymer was successfully applied in fabricating electrochromic devices （ECD） withpoly（3,4-ethylenedioxythiophene）（PEDOT）. The device could change from red（reduced） to blue （oxidized）, and possessed a fast response time. The ECD achieved ahigh coloration efficiency of494cm²C^-1at630nm.3. Poly（2,7-bis （2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl）-naphthalene）P（EDOT-NE）, a novel electrochromic material obtained from3,4-ethylenedioxythiophene （EDOT）-bis-substituted monomer1,4-dibromonaphthalene. The high-quality polymer films were preparedelectrochemically by direct anodic oxidation and the oxidation potential of EDOT-NEin this medium was measured to be only1.0V vs. SCE. The conducting polymerobtained from this medium performed good electrochemical behavior, highelectrochemical stability and thermal stability. Spectroelectrochemical studies haveshown that the polymer has a good electrochromic property that it can changereversibly between the reduced （light-red） and oxidized （light-blue） state with a fastresponse time of1.3s, and exhibits a high coloration efficiency.