| Autor: |
Wang, Siqi, Chang, Cheng, Bai, Shulin, Qin, Bingchao, Zhu, Yingcai, Zhan, Shaoping, Zheng, Junqing, Tang, Shuwei, Zhao, Li-Dong |
| Zdroj: |
Chemistry of Materials; 20230101, Issue: Preprints |
| Abstrakt: |
High carrier mobility is critical to improving thermoelectric performance over a broad temperature range. However, traditional doping inevitably deteriorates carrier mobility. Herein, we develop a strategy for fine tuning of defects to improve carrier mobility. To begin, n-type PbTe is created by compensating for the intrinsic Pb vacancy in bare PbTe. Excess Pb2+reduces vacancy scattering, resulting in a high carrier mobility of ∼3400 cm2V–1s–1. Then, excess Ag is introduced to compensate for the remaining intrinsic Pb vacancies. We find that excess Ag exhibits a dynamic doping process with increasing temperatures, increasing both the carrier concentration and carrier mobility throughout a wide temperature range; specifically, an ultrahigh carrier mobility ∼7300 cm2V–1s–1is obtained for Pb1.01Te + 0.002Ag at 300 K. Moreover, the dynamic doping-induced high carrier concentration suppresses the bipolar thermal conductivity at high temperatures. The final step is using iodine to optimize the carrier concentration to ∼1019cm–3. Ultimately, a maximum ZTvalue of ∼1.5 and a large average ZTavevalue of ∼1.0 at 300–773 K are obtained for Pb1.01Te0.998I0.002+ 0.002Ag. These findings demonstrate that fine tuning of defects with <0.5% impurities can remarkably enhance carrier mobility and improve thermoelectric performance. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
