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Updated: Jul 3, 2026
06:44
From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
Multicentered p-s-p* Antibonding Interaction Induces Strong Anharmonicity and High Thermoelectric Performance in
Anustoop Das1, R Bhuvaneswari2,3, Subarna Das1
1New Chemistry Unit, and School of Advanced Materials and International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur P.O., Bangalore 560064, India.
Journal of the American Chemical Society
|July 2, 2026
Summary
Researchers developed a new metal chalcohalide, Tl5Te2I, exhibiting excellent thermoelectric properties. This material shows promise for efficient energy conversion due to its unique structure and bonding, achieving a high figure of merit.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Condensed Matter Physics
Background:
- Metal chalcohalides offer a unique combination of metal chalcogenide stability and metal halide electronic tunability.
- They are promising for thermoelectrics, needing low thermal conductivity and high electrical conductivity.
- Existing metal chalcohalides often have wide band gaps, limiting electrical transport.
Purpose of the Study:
- To introduce a novel metal chalcohalide, Tl5Te2I, with a narrow band gap and significant electrical conductivity.
- To investigate the structural and bonding attributes of Tl5Te2I for thermoelectric applications.
- To demonstrate the potential of Tl5Te2I for high thermoelectric performance.
Main Methods:
- Synthesis and characterization of the metal chalcohalide Tl5Te2I.
- Exploration of its crystal structure and chemical bonding hierarchy.
- Measurement of its thermoelectric properties, including electrical conductivity and thermal conductivity.
Main Results:
- Tl5Te2I exhibits a narrow band gap and degenerate semiconductor-like electrical conductivity.
- Its complex crystal structure and multicentric bonding framework contribute to low thermal conductivity.
- A high p-type thermoelectric figure of merit (zT) of ~1.2 at ~650 K was achieved in the pristine material.
Conclusions:
- Tl5Te2I demonstrates exceptional thermoelectric performance due to its unique bonding features.
- Multicentric antibonding interactions are key to achieving soft interatomic forces and low thermal conductivity.
- This work highlights mixed anionic chalcohalides as a promising class for advanced thermoelectric materials.
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