Prediction of high thermoelectric performance in the low-dimensional metal halide Cs3Cu2I5

• Published in: npj computational materials Vol. 7; no. 1; pp. 1 - 6
• Main Authors: Jung, Young-Kwang, Han, In Taek, Kim, Yong Churl, Walsh, Aron
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 14.04.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301/299/2736; 639/638/298/917; Anharmonicity; Cations; Characterization and Evaluation of Materials; Chemical sensors; Chemistry and Materials Science; Computational Intelligence; Conduction; Conduction bands; Conduction heating; Crystal structure; Electron mobility; First principles; Halides; Materials Science; Mathematical and Computational Engineering; Mathematical and Computational Physics; Mathematical Modeling and Industrial Mathematics; Metal halides; Phonons; Photovoltaic cells; Solar cells; Theoretical; Thermal conductivity; Thermoelectricity; Transport theory; Vibrations
• ISSN: 2057-3960; 2057-3960
• DOI: 10.1038/s41524-021-00521-9

Metal halides have emerged as a new generation of semiconductors with applications ranging from solar cells to chemical sensors. We assess the thermoelectric potential of Cs 3 Cu 2 I 5 , which has a crystal structure formed of zero-dimensional [Cu 2 I 5 ] 3− anionic clusters that are separated by Cs + counter cations. We find the compound exhibits the characteristics of a phonon-glass electron-crystal with a large imbalance in the conduction of heat and electrons predicted from first-principles transport theory. Strong anharmonic phonon–phonon scattering results in short-lived acoustic vibrations and an ultra-low lattice thermal conductivity (<0.1 W m −1  K −1 ). The dispersive conduction band leads to a high electron mobility (>10 cm 2  V −1  s −1 ). For an n-type crystal at 600 K, a thermoelectric figure-of-merit Z T of 2.6 is found to be accessible, which for a cold source of 300 K corresponds to a thermodynamic heat-to-electricity conversion efficiency of 15%.