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High Thermoelectric Performance in Polycrystalline SnSe Via Dual‐Doping with Ag/Na and Nanostructuring With Ag 8 SnSe 6
Author(s) -
Luo Yubo,
Cai Songting,
Hua Xia,
Chen Haijie,
Liang Qinghua,
Du Chengfeng,
Zheng Yun,
Shen Junhua,
Xu Jianwei,
Wolverton Chris,
Dravid Vinayak P.,
Yan Qingyu,
Kanatzidis Mercouri G.
Publication year - 2019
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201803072
Subject(s) - materials science , thermoelectric effect , crystallite , doping , thermoelectric materials , analytical chemistry (journal) , figure of merit , seebeck coefficient , electrical resistivity and conductivity , phonon scattering , thermal conductivity , valence (chemistry) , single crystal , condensed matter physics , crystallography , optoelectronics , composite material , thermodynamics , metallurgy , chemistry , physics , chromatography , electrical engineering , engineering , quantum mechanics
Abstract Single crystalline SnSe is one of the most intriguing new thermoelectric materials but the thermoelectric performance of polycrystalline SnSe seems to lag significantly compared to that of a single crystal. Here an effective strategy for enhancing the thermoelectric performance of p‐type polycrystalline SnSe by Ag/Na dual‐doping and Ag 8 SnSe 6 (STSe) nanoprecipitates is reported. The Ag/Na dual‐doping leads to a two orders of magnitude increase in carrier concentration and a convergence of valence bands (VBM 1 and VBM 5 ), which in turn results in sharp enhancement of electrical conductivities and high Seebeck coefficients in the Ag/Na dual‐doped samples. Additionally, the SnSe matrix becomes nanostructured with dispersed nanoprecipitates of the compound Ag 8 SnSe 6 , which further strengthens the scattering of phonons. Specifically, ≈20% reduction in the already ultralow lattice thermal conductivity is realized for the Sn 0.99 Na 0.01 Se–STSe sample at 773 K compared to the thermal conductivity of pure SnSe. Consequently, a peak thermoelectric figure of merit ZT of 1.33 at 773 K with a high average ZT (ZT ave ) value of 0.91 (423–823 K) is achieved for the Sn 0.99 Na 0.01 Se–STSe sample.