Micromechanism for Copper-Deficiency Enhanced Stability: A Quasi <i>In Situ</i> TEM Study of Electric-Induced Structural Evolution in Cu<sub>2-<i>x</i></sub>(S, Se) Liquid-Like Thermoelectric Materials.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38407019.
- Also identified by DOI 10.1021/acs.nanolett.3c05087.
- No licence information is recorded for this record.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
Cu-based liquid-like thermoelectric materials have garnered tremendous attention due to their inherent ultralow lattice thermal conductivity. However, their practical application is hampered by stability issues under a large current or temperature gradient. It has been reported that introduction of copper vacancies can enhance the chemical stability, whereas the micromechanism behind this macroscopic improvement still remains unknown. Here, we have established a quasi <i>in situ</i> TEM method to examine and compare the structural evolution of Cu<sub>2-<i>x</i></sub>S<sub>0.2</sub>Se<sub>0.8</sub> (<i>x</i> = 0, 0.05) under external electric fields. It is then found that the preset Cu vacancies could favor the electric-induced formation of a more stable intermediate phase, i.e., the hexagonal CuSe-type structure in the form of either lamellar defects (majorly) or long-range order (minorly), in which ordering of S and Se also occurred. Thereby, copper and chalcogen atoms could largely be solidified into the matrix, and the elemental deposition and evaporation process is mitigated under an electric field.