Uplimit (ZT)max and effective merit parameter B* of thermoelectric semiconductors

Thermoelectric materials directly convert thermal energy and electrical power, attracting wide attention. New materials and new strategies to pursue a high ZT value mark the progress of thermoelectric materials. However, the critical factors relative to a given material's uplimit (ZT)max in the dual-parameter space of temperature carrier concentration are still an open question. In this work, we theoretically show that (ZT)max has a proxi-mately linear relationship with B* that connects the weighted mobility, lattice thermal conductivity, and the bandgap in a single parameter. We also provide insight discussion for achieving a high B* by pursuing high U*, large Eg, and low Klat, or breaking the connections among Klat versus U*, Eg versus Klat, U* versus Eg, suggesting that B* is a good primary effective merit parameter for quick screening new thermoelectric materials.

Automated summary

Thermoelectric materials are of great interest for their ability to convert thermal energy and electrical power. New materials and strategies are being explored to achieve high values of ZT, a key parameter for thermoelectric materials. This study shows that (ZT)max has a nearly linear relationship with B*, which combines mobility, thermal conductivity, and bandgap into a single parameter. The authors suggest that pursuing high values of U*, large bandgap, and low lattice thermal conductivity can lead to high B*, making it an effective screening parameter for new thermoelectric materials.