Quantitative X-ray absorption and emission spectroscopies: electronic structure elucidation of Cu2S and CuS

Abstract

The electronic structures of Cu2S and CuS have been under intense scrutiny, with the aim of understanding the relationship between their electronic structures and commercially important physical properties. Here, X-ray absorption and emission spectroscopic data have been analyzed using a quantitative, molecular orbital (MO) based approach to understand the electronic structure of these two complex systems. Cu2S is shown to have a significant amount of Cu2+ sites and therefore Cu0 centers. The presence of low-valent Cu is correlated with the electrical conductivity of Cu2S, especially at high temperatures. CuS is shown to have tetrahedral Cu2+ and trigonal Cu1+ sites, with crystal planes that have alternating high and low charge on the Cu centers. These alternating charges may contribute to internal energy transitions required for photoluminescence properties. The in-depth electronic structure solutions presented here not only solve a complicated much-debated problem, but also demonstrate the strength of quantitative MO based approach to X-ray spectroscopies

Synthesis and properties of morphology controllable copper sulphide nanosheets for supercapacitor application

“…In addition, the chemometrics of the Cu/S ratio of 1.01 suggests that the sample should be pure CuS. The valance of Cu element in CuS is uncertain until now, Liang et al reported a (Cu 1+ ) 3 [20] and Kumar suggested both Cu 1+ and Cu 2+ exist in covellite CuS [21]. The XPS pattern of Cu is shown in Figure 1(c).…”

Synthesis of CuS nanoparticles by a wet chemical route and their photocatalytic activity

“…and S 2-ions surrounded by CuS 4 tetrahedron of Cu ? and S 2 2-ions (Kumar et al 2013). Recently, CuS nanoparticles have been used as photocatalysts for the degradation of organic dyes such as MB, methyl red, methyl orange, Rhodamine B, and 2,4-dichlorophenol.…”

Copper sulfide nanosheets with shape-tunable plasmonic properties in the NIR region

“…The crystal phase called covellite (CuS) supplements the copper sulfide family with unique physical properties like high holes concentration (up to 10 22 cm -3 [19]) based on the specific crystal structure. Additionally the high degree of hole delocalization is inherent to the covellite phase [24], as well as distinct anisotropic metallic conductivity [25]. Thus, this semiconductor shows a highly pronounced localized surface plasmon resonant (LSPR) absorption peak appearing in the NIR [26] (in the second biological spectral window, 1000-1350 nm [27,28]) in comparison to gold, silver and copper, which are located in the visible range.…”