Effects of structural regulation on the thermoelectric properties of two-dimensional SnSe2 films

The direct conversion of heat and electric energy through thermoelectric effects is one of the effective ways to improve energy efficiency and reduce carbon emission. Thermoelectric parameters are the basis to evaluate the thermoelectric conversion efficiency of thermoelectric materials. However, the measurement of thermoelectric properties in micro/nano thermoelectric materials is extremely difficult at a small scale. Accurate and rapid characterization of thermoelectric parameters is the foundation and key of the optimization design and application of thermoelectric materials. The small-scale and micro-nano structure of materials cannot only effectively change its thermal conductivity, but also affect its electrical conductivity and Seebeck coefficient, thus significantly improving the thermoelectric conversion efficiency. Therefore, it is urgent to study the coupling mechanism between micro-/nano- scale structure regulation and thermoelectric conversion. In this work, an in-situ characterization technique is proposed for the integration of structural regulation and thermoelectric properties of micro/nano materials, and the coupling mechanism is also investigated experimentally. The micro-nano structure of materials is controlled by micro-machining method to realize the adjustable and controllable conversion efficiency. The results demonstrated that structural regulation could effectively improve the ZT value with a maximum improvement of nearly 7 times, which indicated that it was an effective approach to improve the thermoelectric performance.