Tin-Substituted Chalcopyrite An n-Type Sulfide with Enhanced Thermoelectric Performance

Tin-Substituted Chalcopyrite : An n-Type Sulfide with Enhanced Thermoelectric Performance

© 2022 The Authors. Published by American Chemical Society.

Bibliographische Detailangaben
Veröffentlicht in:Chemistry of materials : a publication of the American Chemical Society. - 1998. - 34(2022), 13 vom: 12. Juli, Seite 5860-5873
1. Verfasser: Tippireddy, Sahil (VerfasserIn)
Weitere Verfasser: Azough, Feridoon, Vikram, Tompkins, Frances Towers, Bhui, Animesh, Freer, Robert, Grau-Crespo, Ricardo, Biswas, Kanishka, Vaqueiro, Paz, Powell, Anthony V
Format: Online-Aufsatz
Sprache:English
Veröffentlicht: 2022
Zugriff auf das übergeordnete Werk:Chemistry of materials : a publication of the American Chemical Society
Schlagworte:Journal Article
Beschreibung
Zusammenfassung:© 2022 The Authors. Published by American Chemical Society.
The dearth of n-type sulfides with thermoelectric performance comparable to that of their p-type analogues presents a problem in the fabrication of all-sulfide devices. Chalcopyrite (CuFeS2) offers a rare example of an n-type sulfide. Chemical substitution has been used to enhance the thermoelectric performance of chalcopyrite through preparation of Cu1-x Sn x FeS2 (0 ≤ x ≤ 0.1). Substitution induces a high level of mass and strain field fluctuation, leading to lattice softening and enhanced point-defect scattering. Together with dislocations and twinning identified by transmission electron microscopy, this provides a mechanism for scattering phonons with a wide range of mean free paths. Substituted materials retain a large density-of-states effective mass and, hence, a high Seebeck coefficient. Combined with a high charge-carrier mobility and, thus, high electrical conductivity, a 3-fold improvement in power factor is achieved. Density functional theory (DFT) calculations reveal that substitution leads to the creation of small polarons, involving localized Fe2+ states, as confirmed by X-ray photoelectron spectroscopy. Small polaron formation limits the increase in carrier concentration to values that are lower than expected on electron-counting grounds. An improved power factor, coupled with substantial reductions (up to 40%) in lattice thermal conductivity, increases the maximum figure-of-merit by 300%, to zT ≈ 0.3 at 673 K for Cu0.96Sn0.04FeS2
Beschreibung:Date Revised 19.07.2022
published: Print-Electronic
Citation Status PubMed-not-MEDLINE
ISSN:0897-4756
DOI:10.1021/acs.chemmater.2c00637