Boosting the thermoelectric performance of Bi2O2Se by isovalent doping |
| |
Authors: | Xing Tan Jin‐Le Lan Kerong Hu Ben Xu Yaochun Liu Peng Zhang Xing‐Zhong Cao Yingcai Zhu Wei Xu Yuan‐Hua Lin Ce‐Wen Nan |
| |
Affiliation: | 1. State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, China;2. State Key Laboratory of Organic‐inorganic Composite, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing, China;3. Key Laboratory of Nuclear Analysis Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China;4. Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China |
| |
Abstract: | N‐type Bi2O2Se has a bright prospect for mid‐temperature thermoelectric applications on account of the intrinsically low thermal conductivity. However, the low carrier concentration of Bi2O2Se (~1015 cm?3) severely limits its thermoelectric performance. Herein, the boosting of the carrier concentration to ~1019 cm?3 can be realized in our La‐doped Bi2O2Se ceramic samples, which could be ascribed to the formation of isoelectronic traps and the narrowing of band gap, and contribute to a marked increase in the electrical conductivity (from 0.03 S cm?1 to 182 S cm?1). Our X‐ray absorption near‐edge structure spectra results reveal that a local disordering of oxygen atoms could be an important reason for the intrinsically low thermal conductivity of Bi2O2Se, and the point defects can also suppress the lattice thermal conductivity in La‐doped Bi2O2Se. The ZT value can be enhanced by a factor of ~4.5 to 0.35 at 823 K for Bi1.98La0.02O2Se as compared to the pristine Bi2O2Se. The coordinated optimization of electrical and thermal properties demonstrates an effective method for the rational design of high‐performance thermoelectric materials. |
| |
Keywords: | dopants/doping electrical conductivity thermal conductivity thermoelectric properties |
|
|