The recent discoveries of new quantum materials, the advances in deposition as well as exfoliation methods, and the improved ability to manufacture contacts and interfaces have refocused the interest of the scientific community on electron transport phenomena. A panoply of applications, ranging from electronic to energy conversion devices, relies on optimized charge transport and, in most cases, requires careful balancing of competing degrees of freedom. A typical example is the power factor (PF = S2/ρ, S is the thermopower and ρ the electrical resistivity), which expresses the need to simultaneously optimize charge and entropic components in the electron transport to improve thermoelectric energy conversion.
The search for optimized thermoelectric materials poses also an interesting conundrum because of the delicate balance, which must be achieved between charge and thermal transport. In addition, practical factors such as cost and manufacturability play an important role when discussing materials and properties.
We have done substantial progress in addressing these issues and will present an overview of our recent advances and progress in the design of ternary and quaternary thermoelectric sulfides for mid-temperature applications. Our conclusions are based on a synergistic approach which combines synthesis, characterization, and first principles modeling.
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