In situ study on the thermoelectric properties of monolayer MoS2 film

ZT (thermoelectric figure of merit) is the most direct parameter for the evaluation of the thermoelectric conversion efficiency of materials. At present, the ZT of micro/nanomaterials is often calculated by characterizing thermal and electrical properties separately in different samples, which may cause error propagation or incorrect results. This study used an in situ integrated measurement method for micro/nanomaterials, which can directly measure the ZT and simultaneously obtain their thermal conductivity, electrical conductivity, and Seebeck coefficient at once. The measurements of monolayers MoS2 show a significant coupling of the thermoelectric properties with the structure and temperature. Both samples showed a larger ZT on the narrow edge due to the low thermal conductivity and large Seebeck coefficient. At 474 K, the maximum ZT value of ∼0.02 obtained by combining the thermal and electrical parameters of the same sample showed a significant discrepancy of 1.95 times compared to the in situ characterization result of 0.009. The maximum and minimum ZT values (∼0.050 and ∼0.004) obtained from the combined calculation of the two samples differ even more significantly, amounting to 13.15 times. This study further validates the necessity of in situ characterization for micro/nanomaterials and provides a data reference for the application of MoS2 in the thermoelectric field.