High Thermoelectric Performance in Polycrystalline SnSe Via Dual‐Doping with Ag/Na and Nanostructuring With Ag8SnSe6. Issue 2 (28th November 2018)

• Record Type: Journal Article
• Authors: 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.
• Is Part Of: Advanced energy materials. Volume 9:Issue 2(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-11-28
• Subjects: Ag8SnSe6 -- dual‐doping -- nanostructuring -- SnSe -- thermoelectrics; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.201803072
• Languages: English
• ISSNs: 1614-6832

Abstract

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 Ag8 SnSe6 (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 (VBM1 and VBM5 ), 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 Ag8 SnSe6, which further strengthens the scattering of phonons. Specifically, ≈20% reduction in the already ultralow lattice thermal conductivity is realized for the Sn0.99 Na0.01 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 (ZTave ) value of 0.91 (423–823 K) is achieved for the Sn0.99 Na0.01 Se–STSe sample. Abstract : An effective strategy for enhancing the thermoelectric performance of p‐type polycrystalline SnSe is proposed by Ag/Na dual‐doping and argyrodite Ag8 SnSe6 nanostructuring. The dispersed Ag8 SnSe6 nanoprecipitates are in situ precipitated when the Ag solubility is exceeded. The nanoprecipitates cause a strong scattering of phonons and result in an effective decrease of the already very low thermal conductivity of SnSe.