Silicon quantum dots in thermoelectric material applications

如果我们要减少全球温室气体排放，例如实现欧盟到2050年将温室气体排放量减少80%的承诺，就需要在高效、清洁和安全的能源转换和使用方面取得重大进展。热电材料能够利用废弃或未利用的热源，如炉子、汽车尾气和太阳能电池。因此，热电材料已成为一个非常感兴趣的领域。这些材料能够将温度梯度转化为电能，反之亦然，而无需机械干预。然而，目前生产的商用模块的输出功率并不大，但这些设备产生的功率随后被用于其他低功耗应用，例如为传感器或安全反馈回路供电。我们成功地合成了苯基乙炔功能化硅量子点（SiQDs），显示出提供高效热电材料的潜力。这些共轭配体允许电子通过共轭轨道传递。对该体系的初步表征表明，在300 K时，该体系的电导率为24 S.m-1，导热系数为0.10 Wm-1K-1，塞贝克系数为4148 muVK-1，估计ZT在0.6附近。这些材料的微观传导率和机制的知识将是无价的，我们试图通过设计来改进这些材料。目前的应用是使用独特优雅的μ子光谱方法来测量这些微观性质。

Major advances in efficient, clean and secure energy conversion and use are needed if we are to reduce global greenhouse gas emissions, for example to meet the EU's commitment of a reduction of 80% by 2050. Thermoelectric materials are able to take advantage of wasted or unutilized heat sources, such as in furnaces, car exhausts, and solar cells. As a result, thermoelectric materials have become an area of great interest. These materials are able to convert a temperature gradient into electrical power, and vice versa, without mechanical intervention. The power output from current commercial modules produced are however, modest, but power generated from these devices are then used elsewhere for low power applications, e.g. powering sensors or safety feedback loops. We have successfully synthesized Phenyl-acetylene functionalized Silicon quantum dots (SiQDs) which are showing potential to provide highly efficient thermoelectric materials. These conjugated ligands would allow transport of electrons through the conjugated orbitals. A preliminary characterization of this system, in the bulk, shows an electric conductivity in the region of 24 S.m-1, thermal conductivity 0.10 Wm-1K-1 and a Seebeck coefficient of 4148 muVK-1 at 300 K, with an estimated figure of merit ZT in the region of 0.6. Knowledge of the microscopic conduction rates and mechanisms of these materials would be invaluable in our attempts to improve these materials by design. The present application is to use the uniquely elegant method of Muon spectroscopy to measuring these microscopic properties.