Synthesis And Infrared Emissivity Properties Of PEDOT Based Films

Poly(3,4ethylenedioxythiophene)(PEDOT)is a conductive polymer with conjugated? bonds.As a derivative of polythiophene,its main chain structure is composed of alternating single-double bonds conjugated,PEDOT is an intrinsic conductive polymer material.Because of its good electrical conductivity(>100S/cm),high visible light transparency(>80%),good environmental stability,and compatibility with film fabrication,PEDOT has been successfully applied in many other fields,such as antistatic coatings,transparent supercapacitors,and organic solar cells,thermoelectric generators and etc.This paper focuses on the preparation of the PEDOT-based film and its infrared emissivity performance.With the help of XPS,SEM,XRD analysis and characterization methods,the effects of different oxidant concentrations,co-solvent mixtures,and indium tin oxide nanoparticles(ITO-NPs)on the structure and performance of PEDOT films were studied.The main research work and results are as follows:(1)Using the method of oxidative chemical synthesis,three different oxidants(Fe(Tos)3,Fe(OTf)3,Fe Cl3)were used to synthesize PEDOT films,and the microstructure,electrical and optical performance,infrared emission characteristics of the PEDOT films were studied by means of SEM,XPS,FTIR analysis and characterization methods.The results show that under low oxidant concentration,the PEDOT molecular chains of the coil configuration are stacked on each other to form a loose and porous three-dimensional structure,and with the increase of the oxidant concentration,the degree of chemical oxidation and coil configuration of the PEDOT film gradually increase,and the surface tends to be dense.At the same time,the test results show that the conductivity of the PEDOT film synthesized with an appropriate amount of Fe(OTf)3 can reach 640S/cm,the corresponding integrated transmittance of visible light is 77.06%,and the infrared emissivity is adjustable between 0.26 and 0.48,which is lower than that of traditional commercial PEDOT:PSS.(2)Co-solvents such as NMP and DMSO were added to the precursor solution for the synthesis of PEDOT,and the influence of co-solvents on the structure and performance of PEDOT films were studied by means of SEM,XPS,FTIR analytical characterization methods.The results show that the prepared PEDOT film contains a small amount of co-solvent residues,which increases the degree of chemical oxidation and doping.The bending conformation of the PEDOT chain coil is obviously weakened,the surface roughness of the film is obviously reduced,and the whole PEDOT film is more dense.At the same time,the test results showed that the conductivity of the PEDOT film with an appropriate amount of co-solvent nearly doubled to more than1000S/cm,and the infrared emissivity could be further reduced to 0.21.The infrared thermal imager detected a decrease in the apparent temperature of about 1?.(3)Using in-situ polymerization method to dope ITO-NPs in PEDOT film,with the help of SEM,XPS,XRD,FTIR analysis and characterization methods,the crystal structure and electrical and optical properties influences caused by ITO-NPs filler on PEDOT:ITO composite film were studied.The results show that the surface of the PEDOT:ITO composite film layer is quite rough,its main component is PEDOT,and there are a small amount of ITO-NPs inside,which is(222)preferential crystal plane growth,and the grain size is about 20 nm,agglomerates each other into 100-250 nm clusters distributed in island shape.The test results show that the conductivity of the PEDOT:ITO composite film with a certain doping concentration is increased by about17.2%,reaching 759S/cm,the visible light integral transmittance is reduced to 35.03%,and the infrared modulation range is increased to 0.49?0.63.Compared with the undoped film,it is increased by about 1.37 times,and the infrared apparent temperature difference of the two types of films can reach 12.7?.