Large Mobility Enables Higher Thermoelectric Cooling and Power Generation Performance in n-type AgPb18+x SbTe20 Crystals

The room-temperature thermoelectric performance of materials underpins their thermoelectric cooling ability. Carrier mobility plays a significant role in the electronic transport property of materials, especially near room temperature, which can be optimized by proper composition control and growing crystals. Here, we grow Pb-compensated AgPb18+xSbTe20 crystals using a vertical Bridgman method. A large weighted mobility of similar to 410 cm(2) V-1 s(-1) is achieved in the AgPb18.4SbTe20 crystal, which is almost 4 times higher than that of the polycrystalline counterpart due to the elimination of grain boundaries and Ag-rich dislocations verified by atom probe tomography, highlighting the significant benefit of growing crystals for low-temperature thermoelectrics. Due to the largely promoted weighted mobility, we achieve a high power factor of similar to 37.8 mu W cm(-1) K-2 and a large figure of merit ZT of similar to 0.6 in AgPb18.4SbTe20 crystal at 303 K. We further designed a 7-pair thermoelectric module using this n-type crystal and a commercial p-type (Bi, Sb)(2)Te-3-based material. As a result, a high cooling temperature difference (Delta T) of similar to 42.7 K and a power generation efficiency of similar to 3.7% are achieved, revealing promising thermoelectric applications for PbTe-based materials near room temperature.

Automated summary

The study finds that the electronic transport property of materials can be optimized by proper composition control and crystal growth, resulting in improved room-temperature thermoelectric performance. By growing specific crystals, a high mobility and power factor are achieved, highlighting the importance of crystal growth for low-temperature thermoelectrics. The study also demonstrates the potential of PbTe-based materials for thermoelectric applications near room temperature.