Low-temperature Synthesis of Thermoelectric Materials by Thermal Decomposition of Tailor-made Precursors in Ionic Liquids

该项目将提供改进的合成路线，包括电子掺杂的热电V2VI3 （Sb2Se3, Sb2Te3, Bi2Se3， Bi2Te3和三元溶液）和IV-VI材料（SnSe, SnTe, PbTe），通过单源前驱体的热分解或通过高活性双源前驱体的反应，包括在定制的il中反应性（含金属）离子液体（il）。前驱体允许在低反应温度下合成，并且可以根据其物理化学性质（例如粘度影响质量传输速率，不同前驱体的溶解度等）进行定制。此外，它们保证了高化学计量材料的形成，而il提供了纳米和细观结构的控制。为了鉴定最有前途的il，这些il对金属有机前驱体的溶解度最好，对纳米颗粒表面的结合亲和力最弱，以保证合成不含任何表面活性剂的“裸”纳米颗粒，Kirchner小组（波恩大学）将进行量子化学计算。使用定制前驱体和il的复杂合成的全部优势可以在压实的纳米粉末的热电输运特性中看到。因此，确定最重要的热电性质，如塞贝克系数、功率因数以及导热系数和导电性，对于成功确定最合适的前驱体、il和合成条件至关重要。

The project will provide synthetic routes to improved - included electronically doped - thermoelectric V2VI3 (Sb2Se3, Sb2Te3, Bi2Se3, Bi2Te3 and ternary solutions) and IV-VI materials (SnSe, SnTe, PbTe) either by thermal decomposition of single-source-precursors or by reaction of highly reactive dual source precursors including reactive (metal-containing) ionic liquids (ILs) in tailor-made ILs. The precursors allow for a synthesis at low reaction temperatures and they can be tailored with respect to their physico-chemical properties (e.g. viscosity influencing mass transport rates, solubility of the different precursors etc.). In addition, they guarantee for the formation of highly stoichiometric materials, while the ILs provide control of the nano- and mesostructure. For the identification of the most promising ILs, which show the best solubility for the metal organic precursor and the weakest binding affinity to the nanoparticle surface in order to guarantee the synthesis of "naked" nanoparticles free of any surface surfactants, quantum chemical calculations will be performed by the Kirchner group (Univ. of Bonn). The full advantages of the complex synthesis using tailor-made precursors and ILs can be seen in the thermoelectric transport properties of the compacted nanopowder. Therefore, the determination of the most important thermoelectric properties such as Seebeck coefficient, power factor as well as thermal and electrical conductivity is essential for the successful determination of the most suitable precursors, ILs and synthesis conditions.