Research Projects

Thermoelectrics are being explored as a potential solution for converting waste heat into electricity, particularly in the context of sustainable energy. The argyrodite group, based on the "phonon-liquid electron-crystal (PLEC)" concept, has a complex crystal structure, low lattice thermal conductivity, and low sound velocity, making it an ideal candidate. However, the formation of single-phase argyrodites, low carrier concentration, and low thermal stability due to Ag-ion migration are crucial issues. The current proposal aims to prepare p-Ag9GaTe6 and n-Ag9Gase6 argyrodites without secondary phases using vacuum sealing and a two-step melting process with optimized experimental conditions. The carrier concentration is optimized by tuning the fermi level via bivalent substitution in p-Ag9GaTe6. Entropy engineering is used for n-Ag9Gase6, creating mixed tetrahedral units that improve electrical transport properties. Modifications in the annealing process realign the valence band edge to near the Fermi level, facilitating Ag-ion reorientation and improving thermal stability. The proposal aims to contribute to the development of p-Ag9GaTe6 and n-Ag9Gase6 based legs for thermoelectric prototypes, reducing thermal stress through control of thermal expansion, leg dimensions, and metallic interconnects.