Investigation of the Thermoelectric Properties of Metal Chalcogenides with SnSePublic Deposited
Thermoelectric materials, which convert heat energy to electrical energy, may become increasingly important in the world’s energy situation. Through the inclusion of nanoscale features embedded within a thermoelectric bulk material, it has been shown that a corresponding decrease in lattice thermal conductivity results in an enhanced thermoelectric figure of merit, ZT. This project focused on a new method of nanostructuring: lowering the lattice thermal conductivity by generating a two-phase material in which one phase had nanoscale layers to scatter phonons. The thermoelectric properties of metal chalcogenides with SnSe were investigated for three systems: PbTe-SnSe, PbSe-SnSe, and SnTe-SnSe. PbTe-SnSe formed a solid solution with decreased thermal conductivity over PbTe but poor ZT. PbSe-SnSe and SnTe-SnSe formed multiphase systems with significantly decreased thermal conductivities compared to their parent materials at room temperature (maximum 26.2% and 87%, respectively). In addition, SnTe-SnSe showed promise for further research because it is naturally p-type, less toxic than lead-based materials, and showed a maximum ZT of 0.45 at 700K for a SnTe-SnSe 20% sample.