| Due to the shortage of energy and environmental problems,thermoelectric materials have become a green and very promising alternative energy material,and have a wide scope of development in the field of thermoelectricity.Although existing inorganic thermoelectric materials have excellent thermoelectric properties,their high rigidity,brittleness,expensive raw materials and processing equipment,heavy metal pollution and resource scarcity prevent them from being commonly used in the field of flexible wearable devices.In order to prepare flexible,portable and sustainable self-powered power sources for wearable applications,there is a need to develop thermoelectric materials with superior performance and lower cost.Tellurium-based thermoelectric materials possess excellent quantum-limited effects,large specific surface area,superb phonon scattering properties,and excellent energy density,and their excellent Seebeck coefficients and thermal conductivity make them an ideal thermoelectric material.However,their low electrical conductivity limits their range of applications.Conductive polymers have become a hot research topic in the field of thermoelectric materials today because of their low thermal conductivity,low cost,ease of preparation,and processability.In order to enhance the flexibility and performance of thermoelectric materials,we combined tellurium-based thermoelectric materials and conductive polymers to prepare composites with excellent thermoelectric properties and good flexibility through synergistic effects.The research content of this thesis is divided into the following four parts:(1)Pure Te nanowire dispersions with different ascorbic acid concentrations were prepared by chemical method,and pure Te nanowire films with different components were prepared by vacuum filtration technology.As can be seen from XRD,morphology and XPS characterization,pure Te nanowires were successfully synthesized.The effects of different ascorbic acid concentrations on the thermoelectric properties of pure Te nanowires were studied.Seebeck coefficient reached the maximum value of 524.84μV/K when ascorbic acid was 17.5 g,conductivity and power factor reached the maximum value of 1.04 S/cm and power factor of 17.19μW/m K~2 when ascorbic acid was 15 g.(2)PC-Te nanorods with different ascorbic acid concentrations were prepared by in-situ polymerization,and PC-Te nanorods with different components were prepared by vacuum filtration technology.According to XRD,morphology and XPS characterization,PC-Te nanorods were successfully synthesized,and the effects of different ascorbic acid concentrations on the thermoelectric properties of PC-Te nanorods were studied.Seebeck coefficient reached a maximum of 118.2μV/K when ascorbic acid was 20 g.The conductivity increases with the increase of ascorbic acid concentration and reaches the maximum value of 13.35 S/cm when ascorbic acid is 20g.XPS analysis shows that the increase of conductivity is mainly due to the increase of ascorbic acid concentration,which makes the PEDOT conductive phase in PEDOT:PSS relatively increase and the insulating phase in PSS relatively decrease.The conductivity of the composite film is enhanced.The maximum power factor was 18.66μW/m K~2when the concentration of ascorbic acid was 20 g.(3)Pure Te nanowires and PC-Te nanorods with different ascorbic acid concentrations were combined with conductive polymer PEDOT:PSS according to different mass ratios by mechanical mixing method.Te/PEDOT:PSS composite films and PC-Te/PEDOT:PSS composite films with different mass fractions were prepared.From XRD and morphology characterization,it can be seen that the composite film was successfully prepared.The influence of different mass fractions on the composite film was studied.The Seebeck coefficient of PC-Te/PEDOT:PSS composite films reached the maximum value of 135.76μV/K when the ascorbic acid was 20 g and the mass fraction was 60%.The conductivity and power factor of PC-Te/PEDOT:PSS composite films reached the maximum value of 135.76μV/K when the ascorbic acid was 20 g.When the mass fraction is 80%,the conductivity is 14.99 S/cm,and the power factor is 25.7μW/m K~2.(4)The film samples with the best thermoelectric performance are cut according to fixed specifications,and the cut thermoelectric arms are assembled into flexible thermoelectric power generation devices.The flexibility,stability and feasibility of the device are investigated,as well as the output performance under different temperature differences.At 40 k temperature difference,the output voltage is 30.9 m V,the maximum output power is 9.6 n W,and the maximum power density is 1.06μW/cm~2. |
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