Bonding Hierarchy and Coordination Interaction Leading to High Thermoelectricity in Wide Bandgap TlAgI2

Abstract

High thermoelectric properties are associated with the phonon-glass electron-crystal paradigm. Conventional wisdom suggests that the optimal bandgap of semiconductor to achieve the largest power factor should be between 6 and 10 kbT. To address challenges related to the bipolar effect and temperature limitations, we present findings on Zintl-type TlAgI2, which demonstrates an exceptionally low lattice thermal conductivity of 0.3 W m-1 K-1 at 300 K. The achieved figure of merit (ZT) for TlAgI2, featuring a 1.55 eV bandgap, reaches a value of 2.20 for p-type semiconductor. This remarkable ZT is attributed to the existence of extended antibonding states Ag-I in the valence band. Furthermore, the bonding hierarchy, influencing phonon anharmonicity, and coordination bonds, facilitating electron transfer between the ligand and the central metal ion, significantly contribute to electronic transport. This finding serves as a promising avenue for the development of high ZT materials with wide bandgaps at elevated temperatures.

References in corpus (18)

• Efficient calculation of carrier scattering rates from first principles
• Unified theory of thermal transport in crystals and disordered solids
• Self-consistent phonon calculations of lattice dynamical properties in cubic SrTiO${}_3$ with first-principles anharmonic force constants
• Anharmonic free energies and phonon dispersions from the stochastic self-consistent harmonic approximation: application to platinum and palladium hydrides
• Entropy driven stabilization of energetically unstable crystal structures explained from first principles theory
• Quantum mechanical prediction of four-phonon scattering rates and reduced thermal conductivity of solids
• Lattice anharmonicity and thermal conductivity from compressive sensing of first-principles calculations
• Universality of the Mott-Ioffe-Regel limit in metals
• Modeling heat transport in crystals and glasses from a unified lattice-dynamical approach
• Unusually low thermal conductivity of atomically thin 2D tellurium
• Microscopic Mechanisms of Glass-Like Lattice Thermal Transport in Cubic Cu${}_{12}$Sb${}_4$S${}_{13}$ Tetrahedrites
• Compressive sensing lattice dynamics. II. Efficient phonon calculations and long-range interactions
• Compressive sensing lattice dynamics. I. General formalism
• Electronic fitness function for screening semiconductors as thermoelectric materials
• Impurity clustering and impurity-induced bands in PbTe-, SnTe-, and GeTe-based bulk thermoelectrics
• The role of high-order anharmonicity and off-diagonal terms in thermal conductivity: a case study of multi-phase CsPbBr3
• Bipolar Thermoelectric Josephson Engine
• Zener tunneling in the electrical transport of quasi-metallic carbon nanotubes

Cited by in corpus (3)

• Copper delocalization leads to ultralow thermal conductivity in chalcohalide CuBiSeCl2
• Role of octahedral tilting induced acoustic softening on limiting thermal transport in SrSnO3
• LLM-driven discovery for carbon allotropes with bond-network entropy