碲化锡的微结构调控与热电性能

Microstructure Regulation and Thermoelectric Properties of SnTe

热电材料能够利用固体内部载流子的定向迁移将热能直接转换成电能,在深空探测和工业废热回收发电领域具有广阔的应用前景。影响热电输运行为的多个物理参数之间互相耦合,此消彼长,使材料热电优值的提高困难重重。碲化锡是一种环境友好型中温热电材料,近年来获得了广泛关注。针对碲化锡本征阳离子空位浓度过高、双价带能量差较大、晶格热导率较高等缺点,综述了近10年来关于碲化锡热电输运参数解耦以及热电性能提高的主要方法,包括载流子浓度优化、能带结构调控、晶体缺陷设计与构建等,论述了各优化方法的作用机制和物理本质。指出重掺杂提高碲化锡热电性能的方法会导致其力学性能下降的问题,强调了在实际应用中热电和力学性能的取舍,展望了碲化锡从材料到器件将面临的重大挑战。

Thermoelectric materials can directly convert thermal energy into electrical energy by using the directional transfer of carriers in solid, and have broad application prospects in deep space exploration and industrial waste heat recovery power generation. The physical parameters that affect the thermoelectric transport behavior are coupled with each other, which makes it difficult to improve the thermoelectric figure of merit. SnTe is a kind of environment-friendly mid-temperature thermoelectric materials, which has received extensive attention in recent years. In view of the disadvantages of SnTe such as high concentration of intrinsic cation vacancy, large offset between the two valence bands and high lattice thermal conductivity, the main methods for decoupling thermoelectric parameters and improving thermoelectric performance of SnTe in the past ten years are reviewed, including carrier concentration optimization, energy band structure adjustment, crystal defect design and construction, etc. The mechanism and physical nature of each optimization method are discussed. It is pointed out that heavy doping in SnTe will lead to the decline of mechanical properties while improving thermoelectric performance, and the trade-off between thermoelectric and mechanical properties in practical applications is emphasized. Moreover, the major challenges of SnTe from materials to devices are prospected.