Research progress of tin telluride based thermoelectric materials
摘要
<p indent="0mm">The energy problem is a significant factor constraining the development of human society. Seeking cleaner and more sustainable new energy sources has become a crucial direction in contemporary academic research and industrial development. Thermoelectric materials, which can directly convert heat energy into electric energy and vice versa, have garnered widespread attention due to their simple structure, noiseless operation, pollution-free nature, and high reliability. Unlike solar and wind energy, which require specific external conditions, heat energy is ubiquitous, enabling thermoelectric devices to be applied in a wide range of fields, including extreme environments such as deep space, oceans, deep seas, and deserts, thus supporting energy supply in these areas. Among mid-temperature thermoelectric materials, PbTe boasts the best thermoelectric performance and the most mature development. However, the toxicity of lead limits its broader application. SnTe, with its environmental friendliness as well as the same crystal structure and similar band structure with PbTe, is considered a potential alternative. Nonetheless, the thermoelectric performance of pristine SnTe is inherently inferior to that of PbTe for some reasons. Intitially, SnTe suffers from high hole carrier concentration due to its numerous Sn vacancies in the lattice, which leads to a low Seebeck coefficient and a high electronic thermal conductivity. Additionally, compared to PbTe, SnTe has a smaller band gap between the conduction and valence bands, and a larger energy offset between the light and heavy valence bands. The heavy valence band contributes minimally to electrical transport, which limits the Seebeck coefficient and negatively impacts the thermoelectric figure of merit (<italic>ZT</italic>). Many research efforts have been dedicated to addressing these issues and optimizing the thermoelectric properties of p-type SnTe, yielding a series of significant results. By regulating