Synthesis, Structure, and Properties of CuBiSeCl 2 : A Chalcohalide Material with Low Thermal Conductivity

• Published in: Chemistry of materials 2024-05, Vol.36 (9), p.4530-4541
• Main Authors: Hawkins, Cara J, Newnham, Jon A, Almoussawi, Batoul, Gulay, Nataliya L, Goodwin, Samuel L, Zanella, Marco, Manning, Troy D, Daniels, Luke M, Dyer, Matthew S, Veal, Tim D, Claridge, John B, Rosseinsky, Matthew J
• Format: Article
• Language: English
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/acs.chemmater.4c00188

Mixed anion halide-chalcogenide materials have recently attracted attention for a variety of applications, owing to their desirable optoelectronic properties. We report the synthesis of a previously unreported mixed-metal chalcohalide material, CuBiSeCl ( ), accessed through a simple, low-temperature solid-state route. The physical structure is characterized through single-crystal X-ray diffraction and reveals significant Cu displacement within the CuSe Cl octahedra. The electronic structure of CuBiSeCl is investigated computationally, which indicates highly anisotropic charge carrier effective masses, and by experimental verification using X-ray photoelectron spectroscopy, which reveals a valence band dominated by Cu orbitals. The band gap is measured to be 1.33(2) eV, a suitable value for solar absorption applications. The electronic and thermal properties, including resistivity, Seebeck coefficient, thermal conductivity, and heat capacity, are also measured, and it is found that CuBiSeCl exhibits a low room temperature thermal conductivity of 0.27(4) W K m , realized through modifications to the phonon landscape through increased bonding anisotropy.