Synthesis And Electrochromic Study Of Conducting Polymers Based On Indole[3,2-b]Carbazole

In recent years,the development and application of new materials has attracted people’s attention.Conductive polymer as a new material has been widely used in many fields:military,medical,daily life and so on.As an electrochromic material,it has many advantages that traditional inorganic material can not match,such as large optical contrast,fast response time,high coloring efficiency,strong workability and low energy consumption.In this paper,nine kinds of novel conductive polymers were synthesized and characterized by CV,UV-Vis,SEM,colorimetric and DFT.Firstly,three novelπ-conjugated conductive monomers 5,11-dioctyl-2,8-di（thiophen-2-yl）indole[3,2-b]carbazole（DBTP）,2,8-bis（4-ethylthiophen-2-yl）-5,11-dioctyl-indolo[3,2-b]carbazole（DBETP）and 2,8-bis（2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl）-5,11-dioctyl-indole[3,2-b]carbazole（DBDTP）are synthesied and electrochemically polymerized to form newπ-conjugated conducting polymers,they are PDBTP,PDBETP and PDBDTP respectively.Secondly using thiophene（T）and indole[3,2-b]carbazole（B）as donor,indolylidene ketone（D）as the receptor by chemical synthesis method successfully synthesized three novel conductive polymers:PTDDB-1（T:D:B=4:1:3）,PTDDB-2（T:D:B=2:1:1）and PTDDB-3（T:D:B=1:1:1）.Furthermore,three novel conductive polymers are synthesized by chemical polymerization method,which thieno[3,2-b]thiophene,cyclopentadithiophene and indolinone ketone in different proportions:PTIDD-1,PTIDD-2 and PTIDD-3.Experimental results show that,the color of PDBTP can change from willow yellow to navy when it changes from neutral state to oxidative state,and PDBETP changes from pine color to indigo while PDBDTP changes from light olive to medium grey blue when they undergo the same oxidative process.And the optical contrast and colouring efficiency of PDBTP at 1270 nm were 82.7%and 270.00 cm² C^-1 respectively.PTDDB-2 is changed from indigo blue to bright slate gray when it changes from neutral state to oxidative state.Moreover,the optical contrast of PTDDB-2 at 1580 nm is 62.2%and the coloring efficiency is 210.71 cm²C^-1,and the thermal decomposition temperature of PTDDB-2 is 375℃.From neutral to oxidized states,PTIDD-1 changes from green brown to lead color,while PTIDD-2 changes from ancient purple to pale green,and PTIDD-3 from dark red to transparent blue.The three kinds of conductive polymers all have low optical band gaps,which are 1.52 eV,1.50 eV and1.53 eV,respectively.In the near infrared region,the optical contrast of PTIDD-1 is 72.7%,the coloring efficiency of PTIDD-1 is 466.67 cm² C^-1,the response time of PTIDD-1 is 0.78 s,the PTIDD-2 are 56.9%,300.00 cm² C^-1 and 0.94 s respectively,and the PTIDD-3 are 80.8%,389.47 cm² C^-1,0.36 s,respectively.