Vacancy Suppression and Resonant Level Rendering Extraordinary Power Factor in Sn<sub>0.99</sub>In<sub>0.01</sub>Te/Tourmaline Composite
Zhihao Li, Long Wang, Adeel Abbas, Yujie Zong, Chang‐Heng Tan, Yuqing Sun, Hongxiang Wang, Hongxiang Wang, Wenbin Su, Chunlei Wang, Hongchao Wang, Hongchao Wang
Abstract
Abstract SnTe, as a potential medium‐temperature thermoelectric material, reaches a maximum power factor ( PF ) usually above 750 K, which is not conducive to continuous high‐power output in practical applications. In this study, PF is maintained at high values between 18.5 and 25 µW cm −1 K −2 for Sn 0.99 In 0.01 Te− x wt% tourmaline samples within the temperature range of 323 to 873 K, driving the highest PF eng of 1.2 W m −1 K −1 and PF ave of 22.5 µW cm −1 K −2 , over 2.5 times that of pristine SnTe. Such an extraordinary PF is attributed to the synergy of resonant levels and Sn vacancy suppression. Specifically, the Seebeck coefficient increases dramatically, reaching 88 µV K −1 at room temperature. Meanwhile, by Sn vacancy suppression, carrier concentration, and mobility are optimized to ≈10 19 cm −3 and 740 cm 2 V −1 s −1 , respectively. With the tourmaline compositing, Sn vacancies are further suppressed and the thermal conductivity simultaneously decreases, with the minimum lattice thermal conductivity of 0.9 W m −1 K −1 . Finally, the zT value ≈0.8 is obtained in the Sn 0.99 In 0.01 Te sample. The peak of the power output density reaches 0.89 W cm −2 at a temperature difference of 600 K. Such SnTe alloys with high and “temperature‐independent” PF will offer an option for realizing high output power in thermoelectric devices.