Realizing p-Type MoS2 with Enhanced Thermoelectric Performance by Embedding VMo2S4 Nanoinclusions

Two-dimensional transition-metal dichalcogenide semiconductors (TMDCs) such as MoS2 are attracting increasing interest as thermoelectric materials owing to their abundance, nontoxicity, and promising performance. Recently, we have successfully developed n-type MoS2 thermoelectric material via oxygen doping. Nevertheless, an efficient thermoelectric module requires both n-type and p-type materials with similar compatibility factors. Here, we present a facile approach to obtain a p-type MoS2 thermoelectric material with a maximum figure of merit of 0.18 through the introduction of VMo2S4 as a second phase by vanadium doping. VMo2S4 nanoinclusions, confirmed by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) measurements, not only improve the electrical conductivity by simultaneously increasing the carrier concentration and the mobility but also result in the reduction of lattice thermal conductivity by enhancing the interface phonon scattering. Our studies not only shed new light toward improving thermoelectric performance of TMDCs by a facile elemental doping strategy but also pave the way toward thermoelectric devices based on TMDCs.