Study of thermoelectric properties in the PEDOT:PSS/Te double-layer thin film devices

Abstract

The research on the organic hybrid composites have been regarded as important developing direction in the field of thermoelectric fields, which combine the advantages of organic thermoelectric materials and inorganic thermoelectric materials. In this paper, the thermoelectric properties of Tellurium (Te) and Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hybrid composite thin film and double-layer structured of PEDOT/Te thin film are studied, separately. We found that the PEDOT:PSS/Te double-layer structured thin film thermoelectric devices can greatly improve conductivity and Seebeck coefficient of PEDOT:PSS compared with the hybrid structure of PEDOT:PSS thermoelectric devices. We thought that the semi-metallicity of PEDOT:PSS and Te forms an ohmic contact interface, which is advantageous to charge transfer, so the double-layer structure of thin film devices possess a better carrier transport channels by the interface effect than hybrid structure devices. On the other hand, the C–V results also confirmed that the interfacial charge accumulation in the PEDOT:PSS/Te double-layered thin-film device, when the temperature rises, the Fermi level close to the conduction band as the temperature increases, leading to the number of high-energy carriers increase at the interface, which effectively improves the Seebeck coefficient of PEDOT:PSS. Our research provide experimental and theoretical support for the development of thin-film thermoelectric materials and devices.