Hybrid Thermoelectric Materials Based on Porous Silicon: Linking Macroscopic Transport Phenomena to Microscopic Structure and Elementary Excitations

该项目的目标是开发和了解基于纳米结构硅和官能化聚合物的新型混合热电材料。简而言之，体硅臭名昭著的糟糕热电性能将在由多孔硅作为主体衬底和像PEDOT这样的导电聚合物作为客体分子的混合系统中得到克服。在这里，结构化的主体至少保证非常低的热导率作为优良热电材料的先决条件，而电学性能可以通过适当地选择主体分子来有利地调节。我们建议通过X射线和中子散射实验，将合成的杂化样品的完整宏观、热电特性与结构和动力学研究结合起来。目标是在微观层面上对电导率、热导率和塞贝克系数等宏观参数与电子能带结构和声子色散的关系有一个基本的了解。它将被全面研究，主客体的性质如何与混合系统的性质相关，以及如何产生协同效应。理想情况下，这项研究为更高效的热电材料的新设计策略铺平了道路。

The project objective is to develop and understand novel hybrid thermoelectric materials based on nanostructured silicon and functionalized polymers. In a nutshell, the notoriously bad thermoelectric performance of bulk silicon shall be overcome in hybrid systems consisting of porous silicon as host substrate and conductive polymers like PEDOT as guest molecules. Here the structured host guarantees at least very low thermal conductivity as prerequisite for an excellent thermoelectric material, whereas electrical properties can be favorably tuned by proper selection of the host molecules. We propose to combine a full macroscopic, thermoelectric characterization of synthesized hybrid samples with structural and dynamical studies by means of x-ray and neutron scattering experiments. Goal is a fundamental understanding of how macroscopic quantities like electrical conductivity, thermal conductivity and Seebeck coefficient relate to electronic band structure and phonon dispersion on a microscopic level. It will be comprehensively investigated, how the properties of host and guest relate to the properties of the hybrid systems and how synergy effects might arise. Ideally, this studies pave the route towards novel design strategies for more efficient thermoelectric materials.