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Boosting the thermoelectric performance of Bi 2 O 2 Se by isovalent doping
Author(s) -
Tan Xing,
Lan JinLe,
Hu Kerong,
Xu Ben,
Liu Yaochun,
Zhang Peng,
Cao XingZhong,
Zhu Yingcai,
Xu Wei,
Lin YuanHua,
Nan CeWen
Publication year - 2018
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.15720
Subject(s) - thermoelectric effect , doping , materials science , thermal conductivity , electrical resistivity and conductivity , analytical chemistry (journal) , thermoelectric materials , ceramic , boosting (machine learning) , band gap , condensed matter physics , optoelectronics , chemistry , thermodynamics , electrical engineering , metallurgy , physics , composite material , chromatography , engineering , machine learning , computer science
N ‐type Bi 2 O 2 Se has a bright prospect for mid‐temperature thermoelectric applications on account of the intrinsically low thermal conductivity. However, the low carrier concentration of Bi 2 O 2 Se (~10 15 cm −3 ) severely limits its thermoelectric performance. Herein, the boosting of the carrier concentration to ~10 19 cm −3 can be realized in our La‐doped Bi 2 O 2 Se 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 Bi 2 O 2 Se, and the point defects can also suppress the lattice thermal conductivity in La‐doped Bi 2 O 2 Se. The ZT value can be enhanced by a factor of ~4.5 to 0.35 at 823 K for Bi 1.98 La 0.02 O 2 Se as compared to the pristine Bi 2 O 2 Se. The coordinated optimization of electrical and thermal properties demonstrates an effective method for the rational design of high‐performance thermoelectric materials.