Decreasing the Effective Thermal Conductivity in Glass Supported Thermoelectric Layers

Abstract

As thermoelectric devices begin to make their way into commercial applications, the emphasis is put on decreasing the thermal conductivity. In this purely theoretical study, finite element analysis is used to determine the effect of a supporting material on the thermal conductivity of a thermoelectric module. The simulations illustrate the heat transfer along a sample, consisting from Cu, Cu2O and PbTe thermoelectric layers on a 1 mm thick Pyrex glass substrate. The influence of two different types of heating, at a constant temperature and at a constant heat flux, is also investigated. It is revealed that the presence of a supporting material plays an important role on lowering the effective thermal conductivity of the layer-substrate ensemble. By using thinner thermoelectric layers the effective thermal conductivity is further reduced, almost down to the value of the glass substrate. As a result, the temperature gradient becomes steeper for a fixed heating temperature, which allows the production of devices with improved performance under certain conditions. Based on the simulation results, we also propose a model for a robust thin film thermoelectric device. With this suggestion, we invite the thermoelectric community to prove the applicability of the presented concept for practical purposes.

Thermoelectricity in the context of renewable energy sources: joining forces instead of competing

“…If the thermal conductivity is high, then the temperature difference between both ends will be quickly lowered, decreasing the maximal achievable voltage. 10 As such, it is not unexpected that the combination of these factors, namely the figure-of-merit ZT, is defined as in eqn (1). The power factor PF, a function of S and s, is also often encountered, while the average temperature is denoted T m .…”

Size Dependence of Electrical Conductivity and Thermoelectric Enhancements in Spin‐Coated PEDOT:PSS Single and Multiple Layers

“…Even if significant steps have been made toward elucidating the conduction mechanisms, a deeper understanding is still required to explain these large deviations occurring in the reported literature. Although quantum‐effects, such as quantum‐confinement and boundary scattering, can affect the transport properties at the nanoscale, the influence of the film thickness on the electrical transport is yet to be systematically investigated. While the results presented in a few recent reports give some hints toward a higher performance in thicker conductive layers, these enhancements are rather attributed to the surface treatment, or the physical interactions between different components (e.g., coiling of PANI chains along carbon nanotubes) .…”

In Situ Complementary Doping, Thermoelectric Improvements, and Strain-Induced Structure within Alternating PEDOT:PSS/PANI Layers

“…These values currently hold the record for the thermoelectric performance of organic materials, indicating a massive potential for further development from alternating PEDOT:PSS/PANI layers. Assuming a thermal conductivity (κ) between 0.4 and 24.6 W m –1 K –1 , the resulting figure of merit ZT = (σ S 2 /κ) T of 0.03–2 would make the reported multilayered films highly competitive with more conventional compounds, including chalcogenides, ,− skutterudites, and oxides. ,− In this case, the orientating effect of the carbon nanotubes on the PANI chains seems essential to improve the performance. While PANI:HCl/DWNT-PEDOT:PSS bilayers presented a similarly impressive power factor of approximately 1000 μW m –1 K –2 , the PANI:HCl/graphene-PEDOT:PSS bilayers could only reach 0.14 μW m –1 K –2 with σ = 0.45 S cm –1 after 80 deposition cycles .…”