Temperature driven n- to p-type conduction switching in SnSe and its mitigation through Zn doping with added advantage of Improved thermoelectric performance

Emergent Materials, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 17, 2024

Abstract Tin selenide (SnSe) has emerged as a surprising new p-type thermoelectric material with exceptionally low thermal conductivity, leading to impressive performance. However, the presence of thermally conducting & electrically insulating SnO 2 at grain boundaries SnSe supresses its desirable properties. In this work we report temperature dependence Seebeck coefficient for polycrystalline which exhibits an unusual reversible change in conduction from n- ~ 565 K. The n-type near room is attributed Se deficiency well present boundaries. At high formation Sn vacancies leads conduction. Zn doping site (Sn 1−x x Se) establishes usual entire range along lowering resulting figure-of-merit 0.15 700 K, nearly 275% higher than that pristine SnSe. Graphical abstract

Language: Английский

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Deciphering Pauling’s Third Rule: Uncovering Strong Anharmonicity and Exceptionally Low Thermal Conductivity in TlAgSe for Thermoelectrics

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: unknown

Published: July 26, 2024

Abstract The elucidation of chemical bonding, coupled with an exploration the correlated dynamics constituent atoms, is essential for unravelling underlying mechanism responsible low lattice thermal conductivity (κ L ) exhibited by a crystalline solid, which thermoelectrics and barrier coatings. In this regard, Pauling's third empirical rule, deals cationic repulsion due to proximity in face or edge shared polyhedra crystal structure, can bring about instability required suppress κ . Here, we demonstrate presence such ternary selenide, TlAgSe, leading ultra‐low 0.17 W/m.K at 573 K. Our study reveals arising from Ag−Ag within edge‐shared AgSe 4 tetrahedra through investigation local structure using synchrotron X‐ray pair distribution function (PDF) analysis supported first‐principles density functional theory calculations. We observe correlation between weakening Ag Tl‐sublattice, providing direct experimental evidence rule. rattling Tl induces highly anharmonic energy optical phonons, resulting suppressed sound velocity ultralow TlAgSe. electronic origin soft filled antibonding states valence band near Fermi level constructed Ag(4d)−Se(4p) Tl(6s)−Se(4p) interactions. This work demonstrates that dynamic distortion governed rule given Pauling, act as potential new strategy diminishing solids.

Language: Английский

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Deciphering Pauling’s Third Rule: Uncovering Strong Anharmonicity and Exceptionally Low Thermal Conductivity in TlAgSe for Thermoelectrics

Angewandte Chemie, Journal Year: 2024, Volume and Issue: 136(43)

Published: July 26, 2024

Abstract The elucidation of chemical bonding, coupled with an exploration the correlated dynamics constituent atoms, is essential for unravelling underlying mechanism responsible low lattice thermal conductivity (κ L ) exhibited by a crystalline solid, which thermoelectrics and barrier coatings. In this regard, Pauling's third empirical rule, deals cationic repulsion due to proximity in face or edge shared polyhedra crystal structure, can bring about instability required suppress κ . Here, we demonstrate presence such ternary selenide, TlAgSe, leading ultra‐low 0.17 W/m.K at 573 K. Our study reveals arising from Ag−Ag within edge‐shared AgSe 4 tetrahedra through investigation local structure using synchrotron X‐ray pair distribution function (PDF) analysis supported first‐principles density functional theory calculations. We observe correlation between weakening Ag Tl‐sublattice, providing direct experimental evidence rule. rattling Tl induces highly anharmonic energy optical phonons, resulting suppressed sound velocity ultralow TlAgSe. electronic origin soft filled antibonding states valence band near Fermi level constructed Ag(4d)−Se(4p) Tl(6s)−Se(4p) interactions. This work demonstrates that dynamic distortion governed rule given Pauling, act as potential new strategy diminishing solids.

Language: Английский

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Heterogeneous Cu Doping Facilitates Excellent Thermoelectric and Mechanical Performance in n-Type SnSe Composites

ACS Applied Materials & Interfaces, Journal Year: 2024, Volume and Issue: 16(50), P. 69758 - 69768

Published: Dec. 10, 2024

SnSe materials have attracted extensive attention in thermoelectrics due to their low thermal conductivity. Nevertheless, the thermoelectric properties of n-type polycrystalline are still low, and metallic Sn distributed SnSe1–x would affect repeatability performance. Herein, SnSe0.95-based composites highly enhanced by heterogeneous Cu doping. The carrier concentration SnSe0.95 material was optimized SnCl2 strategy doping is employed further improving performance SnCl2-doped materials. In addition, partial Cu+ tunes electron enhance Seebeck coefficient. Moreover, along grain boundaries can be stabilized forming Cu6Sn5 alloys, which improve stability bulk composites. Excessive particles precipitates strengthen phonon scattering for lowering lattice Ultimately, a peak ZT 1.55 yielded at 773 K SnSe0.95–1 wt % SnCl2–1 composite, whose mechanical hardness also increased. Hence, these results promote feasible approach simultaneously SnSe-based composites, might worth exploring other

Language: Английский

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