Enhanced thermoelectric performance of n‐type Bi2O2Se by Cl‐doping at Se site

• Published in: Journal of the American Ceramic Society 2017-04, Vol.100 (4), p.1494-1501
• Main Authors: Tan, Xing, Lan, Jin‐le, Ren, Guangkun, Liu, Yaochun, Lin, Yuan‐Hua, Nan, Ce‐Wen
• Format: Article
• Language: English
• Subjects: Ceramics; Conductivity; doping; electrical conductivity; Ferroelectrics; layered crystal structures; Plasma sintering; thermoelectric properties; Young's modulus
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/jace.14726

The n‐type polycrystalline Bi2O2Se1−xClx (0≤x≤0.04) samples were fabricated through solid‐state reaction followed by spark plasma sintering. The carrier concentration was markedly increased to 1.38×1020 cm−3 by 1.5% Cl doping. The maximum electrical conductivity is 213.0 S/cm for x=0.015 at 823 K, which is much larger than 6.2 S/cm for pristine Bi2O2Se. Furthermore, the considerable enhancement of the electrical conductivity outweighs the moderate reduction of the Seebeck coefficient by Cl doping, thus contributing to a high power factor of 244.40 μ·WK−2·m−1 at 823 K. Coupled with the intrinsically suppressed thermal conductivity originating from the low velocity of sound and Young's modulus, a ZT of 0.23 at 823 K for Bi2O2Se0.985Cl0.015 was achieved, which is almost threefold the value attained in pristine Bi2O2Se. It reveals that Se‐site doping can be an effective strategy for improving the thermoelectric performance of the layered Bi2O2Se bulks.