posted on 2019-04-03, 00:00authored byLin Sun, Guo Xie, Ping Wu, Yan Xiong, Ling Xu
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 further confirmed that the polarization
effect of MoO3 increases as temperature rises. The polarization
effect promotes the enhancement of thermoelectric properties in the
ITO/P3HT/MoO3/Al device, leading to a big Power Factor
(PF) of 0.203 μW/mK2 at 90 °C. We presuppose
that the introduction of a similar metal oxide interface layer may
be an effective enhancement for the thermoelectric properties of materials
and devices.