Investigation of thermoelectric properties of orthorhombic and rock salt SnS and SnSe from first-principles calculation

Thermoelectric (TE) materials offer direct conversion between thermal and electrical energy and vice versa, which can improve energy efficiency by waste heat recovery and solid-state cooling. Binary Sn chalcogenides, e.g., SnS and SnSe in the orthorhombic phase, have attracted the attention of the thermoelectric community for promising thermoelectric properties. Experimental reports show that SnS and SnSe can form rock salt phases under certain conditions and recent computational studies predict high band degeneracy in the rock salt phase compared to the orthorhombic phase. However, there have been few studies to understand the achievable thermoelectric potential in the rock salt phase, and the comparison of maximum TE potential between both phases is missing. Therefore, in this study, we have applied first-principles modeling of the orthorhombic and rock salt phases of SnS and SnSe to predict the achievable figure of merit zT. Our analysis indicates that there is still an opportunity to improve p-type and n-type zT in SnS, and n-type zT in SnSe in the orthorhombic phase. For the rock salt phase, we predict that SnS might have higher zT than the orthorhombic phase, and comparable zT might be achieved for rock salt SnSe for both p-type and n-type cases. These results motivate continuing analysis of achievable dopability in orthorhombic and rock salt Sn binaries by performing defect calculations to understand the limits of dopability and achievable zT.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2022

Author dc:creator

• Bipasha, Ferdaushi Alam

Contributors dc:contributor

• Ertekin, Elif

• Thermoelectrics
• First-principles
• Semiconductors.

Statement dc:rights

• Copyright 2022 Ferdaushi Bipasha

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/117835

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F117835