Preparation And Thermoelectric Properties Of Organic Conductive Composites Based On Flexible PEDOT:PSS

Approximately 90%of the world's energy is produced by burning fossil fuels.The world's demand for energy has led to a sharp escalation of social and political turmoil.Similarly,the impact of global climate change caused by the burning of fossil fuels on the environment is becoming more and more worrying.In addition,fossil energy technologies cannot meet the rapidly increasing demand for electricity worldwide.It is very urgent to develop new energy conversion technologies to solve this problem.One way to improve the sustainability of our electricity base is to use thermoelectric generators to directly convert waste heat into electricity.Home heating,automobile exhaust,and industrial processes all generate a large amount of unused waste heat,which can be converted into electricity through thermoelectricity.Because thermoelectric generators are solid-state devices that do not need moving parts or produce running noise,they are quiet,reliable and scalable,making them an ideal choice for power supply of miniaturized,portable and wearable electronic devices,which has attracted extensive attention of researchers.As one of the most classic organic conductive polymers,commercially available poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS),due of its high flexibility,environmental stability,and optical transparency at visible range,nontoxicity,etc.,has become a research hotspot.However,in order to meet the requirements of practical applications,the thermoelectric performance of PEDOT:PSS still needs to be further improved,and seeking a composite preparation method is one of the main strategies.In this work,two different flexible composite materials are prepared based on PEDOT:PSS,aiming to improve the thermoelectric properties of the materials through the composite.Secondly,the thermoelectric performance of the composite materials is further optimized through organic solvent post-treatment.The main contents are summarized as follows:1.In this chapter,on the basis of electrostatic interaction,PEDOT:PSS:PANI hybrids were prepared by in-situ composite method,and then the thermoelectric films were obtained by vacuum filtration.The effect of the feeding ratio of the aniline monomer and the post-treatment of various organic solvents on the thermoelectric properties of the films were systematically studied.The advantage of this composite system is that the two polymers have a synergistic effect,that is,the PEDOT:PSS aqueous solution can replace the proton acid to provide protons during the polymerization of aniline,and the sulfonic acid in PSS can improve the solubility and conductivity of PANI.In addition,the PANI:PSS salt formed by complementary doping will increase the electrostatic repulsion of PSS and PEDOT on the main chain,and further improve the conductivity.It is found that the conductivity of the composite reaches 43.7 S cm^-1 when the feeding ratio of the aniline is 20 wt%,which is mainly due to the strong interaction between PSS and PANI.After treated with DMSO&CSA,the power factor was significantly increased to 4.26?Wm^-1 K^-2.The in-situ composite method can provide reference for the combination of various amino derivatives with conductive polymers and the optimization of thermoelectric properties of composite films.2.This chapter mainly studies the effects of PVA and Te levels on the TE and mechanical performance of ternary composite fibers were systematically studied.Furthermore,the TE and mechanical performance of EG-treated PEDOT:PSS/PVA/Te NWs fibers have also been further investigated.The resulting composite fibers have a power factor of 8.5?Wm^-1 K^-2 at room temperature.More importantly,they are mechanically tough,yet very flexible with a tensile strength of 76 MPa and a breaking elongation of 12.3%.It is well known that high tensile strength and appropriate breaking elongation are indispensable and necessary for wearable thermoelectric devices to withstand fabric weaving and human activities.Finally,a simple fiber-based thermoelectric generators(FTEGs)was assembled by integrating with EG post-treated PEDOT:PSS/PVA/Te-NWs hybrid fibers and copper wire,and its output voltage and power density at a temperature difference of 60 K are 5.03 m V and 28.87?W cm^-2,respectively.