Large Mobility Enables Higher Thermoelectric Cooling and Power Generation Performance in n-type AgPb_18+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.