Enhanced Density of States Facilitates High Thermoelectric Performance in Solution-Grown Ge- and In-Codoped SnSe Nanoplates
2022; American Chemical Society; Volume: 17; Issue: 1 Linguagem: Inglês
10.1021/acsnano.2c11095
ISSN1936-086X
AutoresYaru Gong, Shihua Zhang, Yunxiang Hou, Shuang Li, Chong Wang, Wenjie Xiong, Qingtang Zhang, Xuefei Miao, Jizi Liu, Yang Cao, Di Li, Guang Chen, Guodong Tang,
Tópico(s)Chalcogenide Semiconductor Thin Films
ResumoSnSe single crystals have gained great interest due to their excellent thermoelectric performance. However, polycrystalline SnSe is greatly desired due to facile processing, machinability, and scale-up application. Here, we report an outstanding high average ZT of 0.88 as well as a high peak ZT of 1.92 in solution-processed SnSe nanoplates. Nanosized boundaries formed by nanoplates and lattice strain created by lattice dislocations and stacking faults effectively scatter heat-carrying phonons, resulting in an ultralow lattice thermal conductivity of 0.19 W m-1 K-1 at 873 K. Ultraviolet photoelectron spectroscopy reveals that Ge and In incorporation produces an enhanced density of states in the electronic structure of SnSe, resulting in a large Seebeck coefficient. Ge and In codoping not only optimizes the Seebeck coefficient but also substantially increases the carrier concentration and electrical conductivity, helping to maintain a high power factor over a wide temperature range. Benefiting from an enhanced power factor and markedly reduced lattice thermal conductivity, high average ZT and peak ZT are achieved in Ge- and In-codoped SnSe nanoplates. This work achieves an ultrahigh average ZT of 0.88 in polycrystalline SnSe by adopting nontoxic element doping, potentially expanding its usefulness for various thermoelectric generator applications.
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