Realization of high thermoelectric performance in solution-synthesized porous Zn and Ga codoped SnSe nanosheets

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2022-06, Vol.1 (23), p.12429-12437
• Main Authors: Li, Shuang, Hou, Yunxiang, Li, Di, Zou, Bo, Zhang, Qingtang, Cao, Yang, Tang, Guodong
• Format: Article
• Language: English
• Subjects: Carrier density; Decoupling; Electrical conductivity; Electrical resistivity; Energy conversion; Energy conversion efficiency; Heat conductivity; Heat transfer; Machinability; Nanosheets; Phonons; Power factor; Seebeck effect; Synthesis; Thermal conductivity; Thermoelectric materials; Zinc
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d2ta03079a

SnSe is considered one of the most intriguing new thermoelectric materials. Polycrystalline SnSe offers a wide range of thermoelectric applications due to its facile synthetic processing and machinability. Herein, we have achieved a high average ZT of 0.8 as well as a high peak ZT of 1.86 in solution-synthesized porous Zn and Ga codoped SnSe nanosheets, generating a maximum energy conversion efficiency of 13.3%. High-density micro/nanopores are induced in the SnSe matrix, which are more effective for scattering phonons and reducing the thermal conductivity. The high density of micro/nanopores, nanosheet structure and dislocations contribute to an ultralow lattice thermal conductivity (0.157 W m −1 K −1 at 873 K). Meanwhile, Ga incorporation can induce band convergence and create resonance levels, producing a large Seebeck coefficient. Ga and Zn codoping contributes to a sharp increase in carrier concentration and an obviously increased electrical conductivity. The enhanced Seebeck coefficient and increased carrier concentration help in achieving a significant enhancement of the power factor over a wide temperature range in the porous Zn and Ga codoped SnSe nanosheets. Consequently, high thermoelectric performance is realized over a wide temperature range via the decoupling of electron-phonon transport in SnSe. This work opens up a great opportunity for designing prospective materials for thermoelectric applications with the aid of the solution synthesis route. A high average ZT of 0.8 and a high peak ZT of 1.86 are obtained in porous Zn and Ga codoped SnSe nanosheets fabricated by a solution synthesis route.