Periodic Reporting for period 1 - HyThermEl (Hybrid Thermoelectrics: From Model to Device)
Reporting period: 2019-01-15 to 2021-01-14
Europe’s 2030 climate targets make the development of renewable energies a key challenge for researchers across many fields. Thermoelectric generators (TEG) are an emerging technology that promises conversion of the huge amount of waste heat into useful electricity. However, despite big research efforts, they remain niche applications. The reasons are low efficiencies, high costs and scarcity and toxicity of suitable inorganic materials. There is a recent and growing interest in organic-inorganic hybrid TEG. The idea is to combine the advantages of an organic semiconductor (low thermal conductivity, high thermopower) with those of an inorganic nanostructure (high electrical conductivity) by forming a blend of both. Exciting results have very recently been obtained with hybrid materials far outperforming the isolated constituents. This is also a remarkable achievement, given the multi-dimensional parameter space and the absence of a formal framework, forcing progress to be made by mostly heuristic approaches.
HyThermEL aims to develop the first predictive, quantitative model for the performance of hybrid thermoelectric systems. By explicitly accounting for morphology, energetics, interfacial effects and the different transport mechanisms of the constituents, the outcome will be physics-based design rules. In a continuous feedback between experiment and theory, these will be employed to fabricate improved hybrid thermoelectric devices while refining the model. The field of hybrid thermodynamics is still in an initial state, so improved fundamental understanding and practical design rules are expected to have great impact on the community. In particular, we are convinced that current hybrid TEG are still far from their upper performance limits and that this project will open new avenues towards competitive TEG.
Objectives of this action have been to (a) develop a transport model for hybrid thermoelectric blends, (b) measure and model heat conduction, (c) find conditions and design rules for optimized hybrid TEs and (d) realise an optimized hybrid TE system with ZT → 1.
HyThermEL aims to develop the first predictive, quantitative model for the performance of hybrid thermoelectric systems. By explicitly accounting for morphology, energetics, interfacial effects and the different transport mechanisms of the constituents, the outcome will be physics-based design rules. In a continuous feedback between experiment and theory, these will be employed to fabricate improved hybrid thermoelectric devices while refining the model. The field of hybrid thermodynamics is still in an initial state, so improved fundamental understanding and practical design rules are expected to have great impact on the community. In particular, we are convinced that current hybrid TEG are still far from their upper performance limits and that this project will open new avenues towards competitive TEG.
Objectives of this action have been to (a) develop a transport model for hybrid thermoelectric blends, (b) measure and model heat conduction, (c) find conditions and design rules for optimized hybrid TEs and (d) realise an optimized hybrid TE system with ZT → 1.
The project started with an intensive literature research in the field organic and hybrid thermoelectrics as well as literature related to the modelling of the latter two. The result of this study is a published in a book chapter and an upcoming review article.
To reach the objectives of this project, we extended existing kinetic Monte Carlo models to account for variable range hopping in anisotropic media and validated the model with experimental data. The results have been included in the book chapter and two peer reviewed manuscripts. In a second step, the model was extended to energy dependent localization and percolation in different media in form of a host-guest system. Both extensions of the model are validated with experiments and the results are currently prepared for publication in the form of two journal articles.
As a last step, a molecular-dynamics-like model was developed to created complex 3D hybrid morphologies. Experiments to evaluate this tool are under preparation and the results are planned to be published within the near future.
Furthermore, we build a model to simulate heat transport in isotropic and anisotropic systems. The results of this have been published in two peer reviewed journal articles and were presented on two international conferences.
With the named models at hand we gained insights in how to optimize ‘conventional’ and hybrid organic thermoelectrics. This is (and will be) published in the articles connected to the project.
To reach the objectives of this project, we extended existing kinetic Monte Carlo models to account for variable range hopping in anisotropic media and validated the model with experimental data. The results have been included in the book chapter and two peer reviewed manuscripts. In a second step, the model was extended to energy dependent localization and percolation in different media in form of a host-guest system. Both extensions of the model are validated with experiments and the results are currently prepared for publication in the form of two journal articles.
As a last step, a molecular-dynamics-like model was developed to created complex 3D hybrid morphologies. Experiments to evaluate this tool are under preparation and the results are planned to be published within the near future.
Furthermore, we build a model to simulate heat transport in isotropic and anisotropic systems. The results of this have been published in two peer reviewed journal articles and were presented on two international conferences.
With the named models at hand we gained insights in how to optimize ‘conventional’ and hybrid organic thermoelectrics. This is (and will be) published in the articles connected to the project.
The results obtained within the project can help a more targeted development of efficient organic and hybrid thermoelectric devices and with this contribute to the Europeans Commissions priority to transform the Union into a resource-efficient and competitive economy.