Ultralow Thermal Conductivity of a Chalcogenide System Pt3Bi4Q9 (Q = S, Se) Driven by the Hierarchy of Rigid [Pt6Q12]12- Clusters Embedded in Soft Bi-Q Sublattice

Ruiqi Wang; Fei Liang; Xian Zhang; Chendong Zhao; Yuqiang Fang; Chong Zheng; Fuqiang Huang

doi:10.1021/jacs.3c12242

Ultralow Thermal Conductivity of a Chalcogenide System Pt₃Bi₄Q₉ (Q = S, Se) Driven by the Hierarchy of Rigid [Pt₆Q₁₂]^12- Clusters Embedded in Soft Bi-Q Sublattice

J Am Chem Soc. 2024 Mar 20;146(11):7352-7362. doi: 10.1021/jacs.3c12242. Epub 2024 Mar 6.

Authors

Ruiqi Wang^{1

2}, Fei Liang³, Xian Zhang⁴, Chendong Zhao⁵, Yuqiang Fang⁵, Chong Zheng⁶, Fuqiang Huang^{2

5

7}

Affiliations

¹ School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing 101408, P. R. China.
² Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China.
³ State Key Laboratory of Crystal Materials and Institute of Crystal Materials, Shandong University, Jinan 250100, P. R. China.
⁴ Qian Xuesen Laboratory of Space Technology, China Academy of Space Technology, Beijing 100094 P. R. China.
⁵ State Key Laboratory of High-Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, P. R. China.
⁶ Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois 60115, United States.
⁷ State Key Lab of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China.

PMID: 38447048
DOI: 10.1021/jacs.3c12242

Abstract

Knowledge of structure-property relationships in solids with intrinsic low thermal conductivity is crucial for fields such as thermoelectrics, thermal barrier coatings, and refractories. Herein, we propose a new "rigidness in softness" structural scheme for intrinsic low lattice thermal conductivity (κ_L), which embeds rigid clusters into the soft matrix to induce large lattice anharmonicity, and accordingly discover a new series of chalcogenides Pt₃Bi₄Q₉ (Q = S, Se). Pt₃Bi₄S_9-xSe_x (x = 3, 6) achieved an intrinsic ultralow κ_L down to 0.39 W/(m K) at 773 K, which is considerably low among the Bi chalcogenide thermoelectric materials. Pt₃Bi₄Q₉ contains the rigid cubic [Pt₆Q₁₂]^12- clusters embedded in the soft Bi-Q sublattice, involving multiple bonding interactions and vibration hierarchy. The hierarchical structure yields a large lattice anharmonicity with high Grüneisen parameters (γ) 1.97 of Pt₃Bi₄Q₉, as verified by the effective scatter of low-lying optical phonons toward heat-carrying acoustic phonons. Consequently, the rigid-soft coupling significantly inhibits heat propagation, exhibiting low acoustic phonon frequencies (∼25 cm^-1) and Debye temperatures (Θ_D = 170.4 K) in Pt₃Bi₄Se₉. Owing to the suppressed κ_L and considerable power factor (PF), the ZT value of Pt₃Bi₄S₆Se₃ can reach 0.56 at 773 K without heavy carrier doping, which is competitive among the pristine Bi chalcogenides. Theoretical calculations predicted a large potential for performance improvement via proper doping, indicating the great potential of this structure type for promising thermoelectric materials.