AInSn₂S₆ (A = K, Rb, Cs)─Layered Semiconductors Based on the SnS₂ Structure

Abstract

RbInSn 2 S 6 and CsInSn 2 S 6 are yellow two-dimensional (2D) semiconductors featuring anionic SnS 2 -type layers of edge-sharing (In/Sn)S 6 octahedra. These structures are directly derived from the parent structure of SnS 2 by replacement of Sn 4+ atoms with A + and In 3+ atoms. The compounds crystallize, isotypic to the ion-exchange material KInSn 2 S 6 . They adopt the triclinic space group R3̅ m (no. 166). The compounds have similar indirect optical band gaps of 2.31(5) eV for Rb and 2.47(5) eV Cs. The measured work functions for each material are ∼5.38 eV. The density functional theory-calculated effective mass values exhibit strong anisotropy due to the 2D nature of the crystal structures and in the case of CsInSn 2 S 6 for hole carriers along the a, b, and c crystallographic directions are 0.30 m 0 , 0.34 m 0 , and 2.54 m 0 , respectively, while for electrons are 0.06 m 0 , 0.07 m 0 , and 0.47 m 0 , respectively.

Metal Sulfide Ion Exchangers: High Acid Stability of Na2xMg2y–xSn4–yS8 (NMS) and Topotactic Conversion to 2D Solid Acids with Semiconducting Character

“…The band gaps of each parent material are almost identical at 2.40(5) eV for Mg-NMS and 2.42(5) eV for Na-NMS. This result is similar to the values for other reported layered metal sulfides based on SnS 2 ,− and is identical to the bandgap of K 2 MgSn 2 S 6 (KMS-2) . Upon protonation, the band gaps of both materials redshift to 2.30(5) eV for Mg and 2.06(5) eV for Na due to forming a covalent H–S bond, which replaces the ionic Na + –S 2– bond.…”

Structural, Elastic, Mechanical, Electronic, and Optical Properties of a Novel Quaternary Chalcogenide Semiconductor Ba3GeTeS4

“…[3][4][5] Among them, Ba 3 GeTeS 4 has been paid much attention because of its excellent properties, such as high chemical stabilizations, thermoelectric, high-efficiency photocatalysts, and nonlinear optical properties. [6][7][8] Up to now, many efforts have been focused on the search for new photocatalytic materials based on quaternary chalcogenide semiconductor. [9][10][11][12][13][14] It is worth to note that these kind of compounds possess high degree of electron-phonon interaction including anharmonic effects.…”