Enhanced thermoelectric performance of n-type PbTe through the introduction of low-dimensional C60 nanodots

Abstract Lead telluride (PbTe) has long been considered as an ideal p-type thermoelectric material at an intermediate temperature range. However, the relatively low thermoelectric performance of n-type PbTe largely limits the commercial applications of integral PbTe devices. In current work, we report that a significant enhancement of the ZT value of ≈1.3 can be achieved at 823 K in PbTe0.998I0.002-0.5%C60 by adding low-dimensional C60 nanodots. This remarkable improvement in thermoelectric performance is attributed to the incorporation of C60 in n-type PbTe matrix, which creates dense nanodots that can simultaneously manipulate electron and phonon transport. On one hand, the dispersion of C60 nanodots in n-type PbTe matrix leads to highly depressed lattice thermal conductivity (κlat) (∼52%) due to the refinement of grains and the extra phonon scattering centers. On the other hand, the introduction of C60 nanodots increases the scattering parameter rx, and brings about the overall improvement of Seebeck coefficient S, especially at room temperature. This work demonstrates the great potential of low-dimensional dopant in optimizing PbTe thermoelectric materials, which should be equally applicable in improving the performance of other thermoelectric materials.