Unraveling the Role of Entropy in Thermoelectrics: Entropy-Stabilized Quintuple Rock Salt PbGeSnCd_xTe_3+x

Abstract

Entropy-engineered materials are garnering considerable attention owing to their excellent mechanical and transport properties, such as their high thermoelectric performance. However, understanding the effect of entropy on thermoelectrics remains a challenge. In this study, we used the PbGeSnCd x Te3+x family as a model system to systematically investigate the impact of entropy engineering on its crystal structure, microstructure evolution, and transport behavior. We observed that PbGeSnTe3 crystallizes in a rhombohedral structure at room temperature with complex domain structures and transforms into a high-temperature cubic structure at ∼373 K. By alloying CdTe with PbGeSnTe3, the increased configurational entropy lowers the phase-transition temperature and stabilizes PbGeSnCd x Te3+x in the cubic structure at room temperature, and the domain structures vanish accordingly. The high-entropy effect results in increased atomic disorder and consequently a low lattice thermal conductivity of 0.76 W m–1 K–1 in the material owing to enhanced phonon scattering. Notably, the increased crystal symmetry is conducive to band convergence, which results in a high-power factor of 22.4 μW cm–1 K–1. As a collective consequence of these factors, a maximum ZT of 1.63 at 875 K and an average ZT of 1.02 in the temperature range of 300–875 K were obtained for PbGeSnCd0.08Te3.08. This study highlights that the high-entropy effect can induce a complex microstructure and band structure evolution in materials, which offers a new route for the search for high-performance thermoelectrics in entropy-engineered materials.

Pseudo-nanostructure and trapped-hole release induce high thermoelectric performance in PbTe

“…S7 and tables S2 to S5) in the PbTe lattice. Theoretical and experimental results show that the bond lengths of Ge and neighboring Te atoms are different, and a similar off-centered positioning of Ge has been reported in other materials ( 46 , 47 ).…”

Enhancing Thermoelectric Performance in Cubic CuCdInSe3 Compounds via Pressure-Induced Twin Boundary Engineering

“…The discrepancy between the calculated electronic band gap and the optical band gap may be attributed to the perturbations in absorption arising from a substantial presence of free carriers. 43,44 The dominant composition of the top valence band in CuCdInSe 3 (twin GB) predominantly comprises Cu-3d and Se-4p orbitals, while the conduction band bottom primarily originates from In-5s and Se-4p orbitals (Figure 5b). Figure 6a presents the electrical transport properties for the CuCdInSe 3 samples.…”

Lattice dynamics and thermoelectric properties of diamondoid materials

“…[11][12][13][14][15][16][17][18] Numerous excellent thermoelectric materials have been identified. These include Bi 2 Te 3 -based alloys, [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] PbQ (Q = S, Se, Te), [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49] SnSe, [50][51][52][53][54][55][56][57][58][59][60] GeTe, [61][62]…”