Effect of vanadium doping on the thermoelectric properties of MoS2

Recently, MoS2 has been considered as a promising economic and nontoxic thermoelectric material due to its low thermal conductivity and high Seebeck coefficient. However, the poor intrinsic electrical conductivity is still a main obstacle for its wide scale application. Here, we have successfully synthesized p-type V doped MoS2 and systematically investigated the influence of V doping on the thermoelectric properties of MoS2. In the whole doping range, the samples always keep a perfect hexagonal structure. The doped V atoms behave as acceptors and improve the carrier concentration by three to five orders of magnitude, thereby enhancing the electrical conductivity remarkably. In addition, V doping promotes grain refinement and introduces numerous point defects, which play a synergistic role in reducing lattice thermal conductivity. Due to the layered microstructure, obvious anisotropy was observed in the transport properties of VxMo1-xS2. Compared with that of pristine MoS2 (ZT(max) = 0.013 at 860 K), the maximum ZT value of VxMo1-xS2 has been increased to 0.24 at 860 K. (C) 2022 Published by Elsevier B.V.