Large Mobility Enables Higher Thermoelectric Cooling and Power Generation Performance in <i>n</i>-type AgPb<sub>18+<i>x</i></sub>SbTe<sub>20</sub> Crystals
Yingcai Zhu, Yuan Yu, Huaide Zhang, Yongxin Qin, Ziyuan Wang, Shaoping Zhan, Dongrui Liu, Nan Lin, Yinghao Tao, Tao Hong, Siqi Wang, Zhen‐Hua Ge, Matthias Wuttig, Li‐Dong Zhao
Abstract
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.