Executive Summary : | The development of a green, sustainable, and affordable energy economy is one of the preeminent scientific and technological challenges of our time, due to the alarming environmental impact of fossil fuels. Along with improvements in the production and storage of renewable energy, increasing the overall energy efficiency has become indispensable. A promising strategy to meet this goal is the large scale deployment of thermoelectric materials (TEMs), which are able to convert a temperature gradient into an electric voltage (Seebeck effect). To date, this effect is mainly exploited in niche applications, such as the thermoelectric power generation in subsea or space applications. However, recovering otherwise wasted energy via the thermoelectric effect would be very beneficial in many other cases, given that more than half of the energy generated by mankind is lost as unused heat. For this purpose, huge scientific effort has been spent in developing thermoelectric ‘waste heat recovery’ devices, e.g., for the automobile exhaust system and for chemical and industrial plants. The too low efficiency of currently known thermoelectric materials prevents their large scale, cost effective deployment. However, the optimization and development of novel and improved TEMs is a tedious, lengthy and costly task that involves expensive prototyping and extended test series. Naturally, ab initio calculations lend themselves to aid and guide this process: On the one hand, such simulations allow fundamental insights in the electronic and atomistic processes underlying the thermoelectric effect, on the other hand, they also allow a rapid and cost-efficient precreening across the whole periodic system. Recent advances in the field of thermoelectrics are motivated by some of the innovative band engineering approaches, which can either be achieved by compositional tailoring (via doping/ substitution) or are inherent to the bulk material itself. In case of the latter, the materials where spin orbit coupling (SOC) phenomena is strong enough to induce spin dependent band splitting (viz. Rashba Dresselhaus effect) or band inversion (viz. in topological insulators), has proven to be particularly promising for enhancing the thermoelectric performance. The motivation of the present proposal is to perform first principles density functional theory based high throughput calculations to filter Rashba active/ topologically non trivial bulk materials, which also have low lattice thermal conductivity. Once such materials are identified, the next step is to identify proper dopants for injecting charge carriers without affecting the band topologies. Then, the last step of this project will comprise of the synthesis, characterization and analysis of these novel thermoelectric materials (TEM) in the laboratory. Every step of this work will provide a much needed guideline towards the realization of a very high performance thermoelectrics. |