Cu-Doped Cs 3 Sb 2 Cl 9 Nanocrystals: Revisiting the Low Bandgap of Cs 2 CuSbCl 6 Double Perovskites

作者：Simone Virga, David F. Macías-Pinilla, Nicola Dengo, Federica Bertolotti, Alessandro Longo, Fei He, Quinten A. Akkerman, Francesco Giannici · 发表于：ACS Materials Letters · 年份：2025 · DOI：10.1021/acsmaterialslett.5c01043 · 被引用次数：4 · 研究领域：Perovskite Materials and Applications、Optical properties and cooling technologies in crystalline materials、Quantum Dots Synthesis And Properties

High Resolution Image Download MS PowerPoint Slide Lead-free halide double perovskite Cs 2 CuSbCl 6 nanocrystals have recently been reported to have a low bandgap of 1.66 eV. In this work, we show that the optical absorption spectra and X-ray diffraction patterns previously attributed to Cs 2 CuSbCl 6 can rather be explained with Cs 3 Sb 2 Cl 9:Cu: X-ray absorption spectroscopy identifies [CuCl 3 ] − trigonal pyramids, with Cu 2+ possibly replacing two Cs + sites. The broad low-energy optical absorption is then assigned to localized electronic transitions at copper dopants within the Cs 3 Sb 2 Cl 9 lattice, which do not affect the wide bandgap. Ab initio calculations suggest that Cs 2 CuSbCl 6 is thermodynamically unstable with respect to decomposition to Cs 3 Sb 2 Cl 9, in line with the low reproducibility of Cs 2 CuSbCl 6 observed in its synthesis.