Highly efficient and air stable thermoelectric devices of poly (3-hexylthiophene) by dual doping of Au metal precursors

Abstract

The electrical conductivity and doping stability of poly(3-hexylthiophene) (P3HT) in ambient air are significantly improved using a gold chloride dopant, where the coexistence of AuCl4− and Au nanoparticles contributes to high electrical conductivity and doping stability at the same time. The uniformly formed Au nanoparticles induce a facile charge transfer in a thin film of AuCl3-doped P3HT as examined by the crystallography and transmission electron microscopy. P3HT doped with AuCl3 exhibits a high electrical conductivity of 207 S cm−1, a Seebeck coefficient of 73.9 μV K−1, and an optimized power factor of 110 μW m−1 K−2. Importantly, AuCl3-doped P3HT shows excellent air stability. After exposure to the ambient condition for 300 h, the optimized power factor of the AuCl3-doped P3HT maintains over 80% of the initial, whereas that of the FeCl3-doped P3HT decreases to only 20% of the original. Finally, a flexible and organic thermoelectric generator (OTEG) is fabricated using the AuCl3-doped P3HT by slot-die coating. The OTEG shows a relatively high open-circuit voltage (Voc) of 7.96 mV and a short-circuit current (Isc) of 0.93 μA, resulting in a power density of 18.5 nW cm−2 at a temperature gradient of 10 °C.