Large Mobility Enables Higher Thermoelectric Cooling and Power Generation Performance in n -type AgPb 18+ x SbTe 20 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 AgPb 18+ x SbTe 20 crystals using a vertical Bridgman method. A large weighted mobility of ∼410 cm 2 V -1 s -1 is achieved in the AgPb 18.4 SbTe 20 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 ∼37.8 μW cm -1 K -2 and a large figure of merit ZT of ∼0.6 in AgPb 18.4 SbTe 20 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 (Δ T ) of ∼42.7 K and a power generation efficiency of ∼3.7% are achieved, revealing promising thermoelectric applications for PbTe-based materials near room temperature.