Study on Thermoelectric Property of Te Wire-Based Organic-Inorganic Hybrid Thermoelectric Composites through Electrochemical Process

Abstract

Energy demand and importance are increasing with the industrial development and the development of high technology in modern society. However, the global supply of energy is facing problems such as fossil energy depletion and environmental pollution, and research and interest in alternative energy are increasing. Among them, research on thermoelectricity is being actively conducted. The thermoelectric characteristics are represented by the Seebeck coefficient, electrical conductivity, and thermal conductivity at the operating temperature. This is expressed as a thermoelectric performance index (ZT). ZT appears in proportion to the electrical conductivity and Seebeck coefficient, and inversely proportional to the thermal conductivity. Thermoelectric materials are divided into inorganic thermoelectric materials and organic thermoelectric materials, both of which have advantages and disadvantages. The inorganic thermoelectric material has high thermoelectric performance, but it is highly toxic and has low electrical conductivity. On the other hand, organic thermoelectric materials have lower performance than inorganic materials they are easy to obtain and have high electrical conductivity. In this study, organic-inorganic hybrid thermoelectric material was studied by combining the advantages of each material.In this study, Te nanowires (NWs) were synthesized at 50 Co by galvanic replacement reaction. We used Si (1 0 0) wafer as substrate of NWs. The substrate was degreased with acetone and ethanol. The solution of cadmium(1M), hydrofluoric acid (HF 51.0%, 4.5M) and tellurium dioxide (TeO2, 2mM). After the reaction, the synthesized Te NWs were washed with deionized water and IPA. The prepared Te NWs reacted with solution (silver nitrate in ethylene glycol) for topotactic reaction. After the reaction, the wires are washed several times with ethanol. The hybrid TE was fabricated by coating PEDOT:PSS on Ag-Te NWs with different ethylene glycol (EG) doping.A composite thermoelectric material was manufactured using Te (inorganic thermoelectric material) and PEDOT:PSS (organic thermoelectric material). Ag-topotactic reaction was conducted to increase the electrical conductivity of NWs. As the EG doping concentration of PEDOT increased, the electrical conductivity because the layer of PEDOT:PSS became thinner and didn’t fill the gap of NWS sufficiently. In conclusion, the Te NWs coated with PEDOT:PSS with 10% EG doping showed the best electrical conductivity and power factor. The more details will be presented. Figure 1