Ultrahigh thermoelectric performance of 2H–MoS2 nanosheets with incorporated conducting secondary phase

Abstract

The semiconducting molybdenum disulfide (MoS2) is a promising candidate for the thermoelectric power generation applications because of its inherently low thermal conductivity. However, the low electrical conductivity of 2H–MoS2 limits its practical usage. In this report, we have synthesized in situ MoS2 nanostructures with conducting secondary phase (Mo2S3) by hydrothermal method and demonstrated an ultrahigh enhancement in the figure–of–merit of MoS2. A ∼70 times enhancement in the electrical conductivity is observed for the secondary phase (Mo2S3) incorporated MoS2 sample. The presence of optimum barrier height (72 meV) for Mo2S3 incorporated MoS2 is attributed to the enhancement in the Seebeck coefficient due to low energy carrier filtering. The reduction in thermal conductivity of MoS2 in the presence of Mo2S3 is due to more phonon scattering at the interfaces in Mo2S3–MoS2 nanocomposite sample.