The Synthesis And Electrochromic Study Of Conjugated Polymers Based On Carbazole,Dioxythiophene And Benzodithiophene

Although conductive polymers have been developed for decades,they are still critical and mesmerizing in the research field.This should attribute to outstanding performance that conductive polymers have not only unique electrical properties,optical properties and redox activity,but also physical properties.Furthemore,strong processability and flexibility make them more attractive;at the meanwhile,it has wide spread applications in various aspects such as energy-saving materials,bioengineering,medical engineering,electrode materials,and electromagnetic shielding.From the discovery of previous polymers to the pratical application in real life,it is the result that researchers have been constantly trying new materials and optimizing their properties.As we all know,conductive polymers can more easily reduce the optical band gap of polymer to obtain excellent properties through the innovative design of D-A type molecular structure in practical applications.Therefore,the target color can be better obtained and making the color change can be diversified through its molecular design and doping-dedoping theory.This method expands the use of conductive polymers,while accelerating its research process.In this dissertation,ten original conductive polymers with low band gap and special properties were synthesized by the method of chemical polymerization with indole[3,2-b]carbazole,quinoxaline,benzotriazole,benzodithiophene and their derivatives as the precursors.There are PBTDDC,PBBDDC,PTTDC-1,PTTDC-2,PTTDC-3,PBDTD-1and PBDTD-2,PDBBQ-1,PDBBQ-2,PDBBQ-3.At the same time,they are studied electrochromic properties in detail.It has been shown that the E_g values of PTTDC-1,PTTDC-2 and PTTDC-3 were all less than 2.10e V,and its the E_onset also were all less than 0.87V,which belongs to the range of medium band gap,especially,PTTDC-1 have changed three different colors,including red,gray and green,so it is an in dispensable feature in the field of electrochromic.Therefore,these electrochromic materials can be better applied in photovoltaic cells and displays.The long alkyl chain and thiophene groups introduced by indolo[3,2-b]carbazole in PBTDDC and PBBDDC,not only increase the polymer's solubility but also make their electrochromic properties have greatly improved.The results indicated that they have significant changed in color and showed the characteristic with good optical contrast and stability.The optical contrasts of PBDTD-1 and PBDTD-2 were 52.7%and 58.9%in the near infrared region,respectively,and the coloration efficiency were 396.95cm²·C^-11 and 335.32cm²·C^-1,respectively.It is means that it will improve work efficiency and short the operation time in the application.PDBBQ-1,PDBBQ-2 and PDBBQ-3 were discussed and detected by the method of changing feed ratio.According to the test results,there are still many defects that limited the development of conductive polymers.