Mercurial possibilities: determining site distributions in Cu₂HgSnS₄ using ^63/65Cu, ¹¹⁹Sn, and ¹⁹⁹Hg solid-state NMR spectroscopy

Abstract

Chalcogenides are an important class of materials that exhibit tailorable optoelectronic properties accessible through chemical modification. For example, the minerals kesterite, stannite, and velikite (Cu2MSnS4, where M=Zn, Cd or Hg,...

Accurate X-ray diffraction data required for proper evaluation of bond valence sums and global instability indexes: redetermination of the crystal structures of diamond-like Cu2CdSiS4 and Cu2HgSnS4 as a case study

“…This relatively narrow bandgap and the high symmetry of the stannite-type structure suggests that this compound may have potential as a thermoelectric material. Our findings agree with the experimental bandgap of 0.9 eV found by Bhattacharya et al (2022). Several computational studies estimated a direct bandgap in the range 0.103-1.33 eV (Bhattacharya et al, 2022;Hasan et al, 2021;Kukreti et al, 2021;Sarmadian et al, 2016;Vu et al, 2019).…”

“…Our findings agree with the experimental bandgap of 0.9 eV found by Bhattacharya et al (2022). Several computational studies estimated a direct bandgap in the range 0.103-1.33 eV (Bhattacharya et al, 2022;Hasan et al, 2021;Kukreti et al, 2021;Sarmadian et al, 2016;Vu et al, 2019). These computational studies used either the stannite-type or kesterite-type structures, as there has been no single-crystal X-ray diffraction analysis of this compound until now.…”

“…However, powder X-ray diffraction cannot accurately distinguish between the stannite and kesterite structure types, as both provide statistically acceptable results (Kabalov & Evstigneeva, 1998;Sinagra et al, 2021). Additionally, a series of recent computational studies based on both the possible I42m and I4 space groups for Cu 2 HgSnS 4 (Bhattacharya et al, 2022;Hasan et al, 2021;Kukreti et al, 2021;Sarmadian et al, 2016;Vu et al, 2019) have shown varying rationale for each structure type. Therefore, with the structure type remaining ambiguous and no published structure yielding an acceptable G value, any further computational study may be scrutinized.…”

Designing Graded Band Gap Active Layer Cu2HgSn(S1–xSex)4 over Complex Tandem Structure for Efficient Photovoltaic Cells with Efficiency >20%

“…However, the high voltage deficit due to the inevitable Cu Zn antisite , deep defect in Cu 2 ZnSnS 4 material is the concern that motivated the researchers to opt for another element instead of Zn, having a more significant ionic size mismatch compared to Cu + ion. In this series, several cation substitutions are suggested, like Ba, Hg, − Sr, and Fe ion in the place of Zn. Though these are suitable for getting rid of the Cu Zn deep defect at the same time, it affects the band gap value and, finally the photovoltaic response.…”

Alkali Tin Halides: Exploring the Local Structure of A2SnX6 (A = K, Rb; X = Cl, Br, I) Compounds Using Solid-State NMR and DFT Computations

“…However, it is yet to be demonstrated experimentally. While the average long-range structures of A 2 SnX 6 materials are known from diffraction techniques, ,− solid-state nuclear magnetic resonance (NMR) spectroscopy, a complementary method that can be used to study local structure and dynamics, ,,− is nearly absent from their suite of characterizations . Only recently has NMR spectroscopy been used to investigate Cs 2 SnX 6 , revealing important information about octahedral lattice dynamics, which is a property known to influence the optoelectronic properties of these materials. , …”