Deciphering the superior thermoelectric property of post-treatment-free PEDOT:PSS/IL hybrid by X-ray and neutron scattering characterization

In this work, a polymer and ionic liquid (IL) hybrid with superior thermoelectric performance is prepared via a system design of the chemical composition, molar ratio of the constituent molecules and manipulating the structure in solution and dried films. The solution-casted hybrid film, consisting of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and 1-ethyl-3-methylimidazolium tricyanomethanide (EMIM:TCM), shows the highest power factor of 175 mu W m(-1) K-2 in the polymer hybrid prepared by a post-treatment-free method. With a set of complementary structure characterization methods, it is found that EMIM:TCM can induce the structure reorganization of PEDOT:PSS in solution from a core-shell model to a rod-like model, during which PEDOT partially separates from PSS that eases the conductive network formation. In addition, the oxidation level of PEDOT:PSS is reduced by adding EMIM:TCM. Based on which, the PEDOT:PSS/IL hybrid shows the best performance in optimizing the conductivity (1163 S cm(-1)) and Seebeck coefficient (38.8 mu V K-1) simultaneously.

Automated summary

A polymer and ionic liquid hybrid with superior thermoelectric performance was prepared through system design and structure manipulation in solution. It showed high power factor and optimized conductivity and Seebeck coefficient.