| Organic conductive polymers have unique optoelectronic properties due to their?conjugated system,especially their low price,easy processing and rich colors,which have important scientific research value and broad commercial application prospects.At present,they have become a rapidly developing field in material science.Among them,typical five-member unsaturated heterocyclic polymers,such as polythiophene,have been widely studied and applied in solar cells,organic field effect transistors and other fields because of its high electrical conductivity and good environmental stability.It is worth noting that the furan as homologue of thiophene,it has excellent planarity,solubility,luminance and the advantages of the biodegradability,a large number of studies have shown that the organic molecular structure of the polymer polyfuran exhibits significant optical,electrochemical and charge transport properties.Both experimental and theoretical studies have proved that polyfuran derivatives are a kind of excellent green semiconductor materials.However,the research progress of polyfuran derivatives as important five-element semiconductor materials is slow.The main reason is that the high oxidation potential of furan leads to the poor conjugated structure of polyfuran prepared by traditional polymerization method,the synthesis of furan monomers is difficult,and the instability in the air and light,etc.,which greatly limit their research and development.At present,the research progress of polyfuran materials mainly comes from the research of basic theoretical problems and the preliminary application exploration stage.For example,furan has potential application value in fields such as field effect transistors and organic solar cells,mainly as a building block of polymers by virtue of its excellent planarity and luminescence,and is even better than polythiophene materials.In addition,the research and application of other organic materials are not yet mature,such as the research in the field of smart capacitors,thermoelectricity,electrochromic materials and other new green energy fields are less.In this thesis,a series of high quality polyfuran thin films were obtained by using the electrochemical polymerization method as the main polymerization method through the rational design of the molecular structure of furan derivatives.Further,the photoelectric chemistry,electronic properties and thermoelectric properties of polyfurans were systematically studied,and the practical application prospect of polyfurans in green organic electronic materials were successfully expanded.The specific research contents and conclusions are as follows:1.In this work,we electrodeposited and characterized series poly(2,2'-bifuran)(P2Fu),poly(2,2':5',2''-terfuran)(P3Fu),and poly(2,2':5',2'':5'',2'''-quaterfuran)(P4Fu)based furan heterocycle to understand the molecular structure induce the changes of optical and electronic properties.As expected,flexible free-standing films were polymerized at low potential with improved stability.By virtue of its favorable electronic structure and inherent electrochromic,the tailored P4Fu reveals its potential for dual-function electrochromic-supercapacitor(DES)applications via systematic cyclic voltammetric and galvanostatic techniques,showing noticeable multicolor,high CE(330.5 cm2 C-1),and high specific capacitance(241.6 F g-1/1.0A g-1),which are much attractive than those of polythiophene derivatives,even superior to the heterocyclic counterparts.This is also the first time to explore the DSC application potential of polyfuran.Furthermore,a DSC device was successfully assembled by using P4Fu as the activation layers,which can monitor the energy storage level through color conversion.The research demonstrates an important step toward environmentally compatible electronics,and provides novel green material options for high-available organic smart devices.2.In this work,2-(thiophen-2-yl)furan monomer,namely the molecular structure of thiophene and furan ring,were synthesized by Stille coupling reaction.A free-standing poly(thiophene-furan)(PTFu)film with metallic luster was first successfully prepared by electrochemical polymerization method in neutral electrolyte system,and its thermoelectric property was investigated for the first time.The as-prepared PTFu shows high quality and good electrochemical reversibility.Optical absorption spectra of the film indicated that the electrochemical doping method can control the doping state of polymer.The electrical conductivity of the treated electrochemically film was significantly increased to the maximum of 5.5×10-2 S cm-1 at 0.6 V,the Seebeck coefficient reached up to 103.5mV K-1 when the polymer was in a de-doping state.As a result,the doped polymer film was promoted to achieve the remarkable power factor of 1.5×10-2m W m-1 K-2at 0.4 V,which was about 24 times higher than that of the initial PTFu film.Thus,it is proved that electrochemical doping is an efficient strategy for the improvement of thermoelectric properties of conducting polymers.3.The PTFu films prepared in the above experiments can achieve reversible redox conversion under different external applied voltages and with a variety of color changes.The electrochemical and photoelectrochemical analyses of the as-prepared PTFu demonstrate that it has achieved the improved EC performance compared with pure polyfuran and polythiophene polymers,and as a result it possesses favorable ECparameters manifested as a reasonable?T(32.1%),faster response(1.38 s),excellent coloration efficiency(CE,300.9 cm2·C-1),and after a continuous redox process up to 2000 s,its optical stability can be maintained at 96%,and even after 3000 s,it can still be maintained at 80%.In addition,the successful assembly of the electrochromic device of PTFu film can easily realize the reversible conversion of the color from orange to gray.All these systematic studies suggest that the as-prepared flexible PTFu film is a promising candidate for EC materials and has great potential interest for versatile EC applications. |
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