Highly Efficient and Flexible Thin Film Thermoelectric Materials from Blends of PEDOT:PSS and AgSb0.94Cd0.06Te2

Abstract Mechanically stable and flexible composite TE thin films based on PEDOT:PSS and AgSb0.94Cd0.06Te2 blend by hot pressing on porous PVDF substrate are fabricated. A considerable enhancement of S and σ is observed in the regime of 60–97.5 wt.% of AgSb0.94Cd0.06Te2. High Seebeck coefficients of up to 204.9 µV K−1 and a high‐power factor of 53.45 µW m−1 K−2 are obtained for 97.5 wt.% of AgSb0.94Cd0.06Te2 content. However, there is a decrease in electrical conductivity on bending or storage under air. No loss of mechanical integrity can be detected in the SEM of bent films. Ultraviolet photoelectron spectroscopy reveals that overall energy levels of composite systems are either similar to PEDOT:PSS (φ = 5.00 ± 0.16 eV, IP = 5.12 ± 0.02 eV) or AgSb0.94Cd0.06Te2 (φ = 4.43 ± 0.11 eV, IP = 4.57 ± 0.01 eV), depending on the blend ratio. Transport mechanisms are studied using Mott–Schottky measurements, and by calculating the weighted charge carrier mobility, which increases continuously up to 5.5 cm2 V−1 s−1 for the highest inorganic content. It is demonstrated that a high inorganic content TE composite results in a flexible TE film achieving 80% of the Seebeck value of the pure inorganic component.