Polarization Effect of MoO3 Increases the Thermoelectric Properties Based on the PbS Quantum-Dots Doped P3HT Devices

In this article, we fabricated PbS quantum-dots doped P3HT thin films, and their thermoelectric properties were enhanced by introducing the MoO3 interface layer into the ITO/PbS-doped P3HT/Al device. We found that the electrical conductivity of the P3HT thin film increased after only doping PbS quantum-dots, while its Seebeck coefficient decreased. After introducing the MoO3 interface layer into the device forming the ITO/P3HT/MoO3/Al structure, its electrical conductivity and the Seebeck coefficient increased simultaneously. Since the dielectric constant of MoO3 increases with rising temperature, we considered that the MoO3 interface layer brings a polarization effect with temperature changes. A polarization difference occurs between the MoO3 layer and the electron–phonon coupling in the P3HT material. The polarization difference and the entropy difference together drive the carriers to transport from the high temperature to the low temperature. The capacitance–frequency (C–F) characteristic results furt...