Open AccessEnhanced Thermoelectric Performance in Li Doped SnS via Carrier Concentration Optimization
Author(s) -
Yi Niu,
Yide Chen,
Jing Jiang,
Yan Pan,
Chengcheng Yang,
Chao Wang
Publication year - 2020
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/738/1/012016
Subject(s) - materials science , thermoelectric effect , doping , dopant , thermal conductivity , phonon scattering , thermoelectric materials , condensed matter physics , tin , electron mobility , phonon , analytical chemistry (journal) , optoelectronics , chemistry , thermodynamics , metallurgy , physics , chromatography , composite material
Tin sulfide (SnS) has attracted increasing attentions due to its similar band structure and crystal structure to tin selenide (SnSe). The layered structure and strong anharmonicity of these materials result in an ultralow lattice thermal conductivity, which is advantageous for the thermoelectric performance. Further enhancement in thermoelectric properties is expected to improve the carrier concentration and power factor by band structure optimization. In this work, lithium (Li) is proved to be an efficient dopant for SnS and the carrier concentration is increased to 1.3 × 10 18 cm - 3 at room temperature for Sn 0.98 Li 0.02 S. Calculations show that Li doping flattens the edge of the valence band and increases the number of carrier pockets in SnS, which collectively enhance the electronic transport properties. Moreover, the phonon scattering was enhanced by the nano-precipitates and increased boundaries in Sn 1-x Li x S, resulting in 40% reduction in thermal conductivity at room temperature. Combined with the enhanced power factor (∼3 μW cm - 1 K - 2 at 848 K) and low thermal conductivity (0.36 W m - 1 K - 1 at 848 K), the maximum ZT of 0.66 is achieved in Sn 1-x Li x S bulk samples at 848 K.