Complete Thermoelectric Characterization of PEDOT:PSS Thin Films with a Novel ZT Test Chip Platform

Abstract

For the first time, a complete thermoelectric characterization of PEDOT:PSS thin films is performed with a novel lab‐on‐a‐chip measurement platform, which Is developed for the nearly simultaneous in‐plane ZT characterization. The electrical conductivity, the Seebeck coefficient, the thermal conductivity, and consequently the power factor and ZT values as a function of temperature in a single measurement run is experimentally determined. A clear correlation is found between the film thickness of PEDOT:PSS and the thermoelectric properties. While the electrical conductivity increases with decreasing thickness, the thermal conductivity shows a contrary behavior. Both parameters increase monotonically with increasing temperature between 173 and 373 K. The Seebeck coefficient exhibits the same temperature dependency but, in contrast to the previous two parameters, is almost independent of the PEDOT:PSS film thickness. Furthermore, it is demonstrated that a ZT chip, with a complete set of thermoelectric test structures, can be successfully used for a full thermoelectric characterization of conductive organic thin films. This translates into a major testing time advantage for the screening and optimization of promising organic materials during the R&D phase, which can serve as potential candidates for future thermoelectric applications and devices.

Effects of different electrolytes and film thicknesses on structural and thermoelectric properties of electropolymerized poly(3,4-ethylenedioxythiophene) films

“…Furthermore, it is necessary to investigate the optimum lm thickness for PEDOT lms because organic conducting polymers change in electrical conductivity with increasing lm thickness. 36,37 In this study, PEDOT thin lms were fabricated using electropolymerization on indium-tin-oxide (ITO) substrates with methanol/water and acetonitrile as the electrolytes. The electropolymerization time was changed to increase the lm thickness.…”

Impact of Morphology on Charge Carrier Transport and Thermoelectric Properties of N‐Type FBDOPV‐Based Polymers

“…A ZT of (1.7 ± 0.1) × 10 −4 at 303 K was achieved, remaining far below requirements for practical applications [ 64 ] but being strikingly in the same range than the ZT of PEDOT:PSS (p‐type) measured on a single sample (≈9.6 × 10 −4 at 303 K, Table S5, Supporting Information). [ 65 ] Thermal stability is also paramount for thermoelectric applications. In overall, the thermoelectric parameters of doped P(FBDOPV‐2T‐C 12 ) are highly stable over five heating–cooling cycles under secondary vacuum.…”

Doping High‐Mobility Donor–Acceptor Copolymer Semiconductors with an Organic Salt for High‐Performance Thermoelectric Materials

“…Note that in our thermoelectric measurement setup, all three characteristic parameters, namely σ, S , and κ, were measured on the same sample in the in‐plane direction. Therefore, the ZT values presented in this work stand the actual in‐plane thermoelectric properties with an error bar around 15% 43…”

“…Therefore, the ZT values presented in this work stand the actual in-plane thermoelectric properties with an error bar around 15%. [43] In conclusion, we have performed systematic studies of the thermoelectric properties of a high-mobility D-A copolymer semiconductor PCDTPT, which was doped by an organic salt dopant TrTPFB. The combination of UV-vis-NIR spectra and ESR characterizations indicates that the dopant can effectively p-dope the semiconductor, and thus has a dramatic influence on the electrical conductivity and Seebeck coefficient.…”

“…Electrical Conductivity, Seebeck Coefficient and Thermal Conductivity Measurements: To characterize the thermoelectric properties of our samples, the as-fabricated solutions with various doping ratios were separately transferred onto pre-structured measurement platforms (see Figure S1, Supporting Information) [42,43] via dip-dropping method. First, the platforms were baked on a hot plate at 50 °C for 12 h, and then annealed at 150 °C for 10 min.…”