Synthesis, Crystal Structure, and Photoelectric Properties of a New Layered Bismuth Oxysulfide

Abstract

[Bi2O2]-containing tetragonal compounds have received enormous attention due to unique functions including ferroelectricity, photocatalysis, and superconductivity. Here, a new layered compound Bi9O7.5S6 was synthesized via a facile hydrothermal route. The compound, belonging to a new structure type crystallizes in a rhombohedral system with space group R3̅m (a = 4.0685(1) Å, c = 31.029(5) Å, V = 444.8(1) Å(3), Z = 1). The overall crystal structure consists of alternatively packed unique [Bi2O2] and [BiS2] layers along [001] which are combined with each other by van der Waals interaction. The phase purity of the product is confirmed by powder X-ray diffraction. XPS analyses indicate +3 for Bi and -2 for S atoms. The temperature dependence of resistivity ρ(T) indicates that the semiconducting sample follows the mechanisms of variable range hopping (VRH) and adiabatic small polaron hopping (SPH). The direct-transition band gap, Eg = 1.27 eV derived from optical absorption spectrum, falls in the optimal region of solar absorber materials. Accordingly, the photoelectric measurement demonstrates the potential for applications for photovoltaic devices.

Bismuth Oxysulfide Photoelectrodes with Giant Incident Photon‐to‐Current Conversion Efficiency: Chemical Stability in Aqueous Solutions

“…As is known, both bismuth oxyiodide and oxysulfide possess the similar layered structure . The main difference consists in the Van der Waals planes in BiOI formed by the iodine atoms instead the sulfur atoms in bismuth oxysulfide ,,,,. Under a contact of the BOS with I 2 − /I − solution, the formation of BiOI takes place due to the ion exchange reaction between S 2− anions in semiconductor and I − anions in solution.…”

“…Nowadays, there are a number of known bismuth oxysulfide compounds: Bi 2 O 2 S, Bi 2 OS 2 , Bi 3 O 2 S 3 ,, Bi 4 O 4 S 3 ,, Bi 9 O 7.5 S 6 , Bi 10 O 6 S 9 . These materials have a layered structure and are characterized by the pronounced anisotropy of electronic properties . Bi 3 O 2 S 3 and Bi 4 O 4 S 3 are of great interest for superconductive materials design ,.…”

“…Bi 3 O 2 S 3 and Bi 4 O 4 S 3 are of great interest for superconductive materials design ,. Bi 2 O 2 S, Bi 2 OS 2 , Bi 9 O 7.5 S 6 and Bi 10 O 6 S 9 with relatively low band gap energy (0.99–1.38 eV) are the promising compounds for photosensing and solar energy conversion ,,,…”

Metal Oxysulfides: From Bulk Compounds to Nanomaterials

“…In comparison with Ln 2 O 2 S in which Ln forms four Ln-O and three Ln-S bonds, bismuth-oxygen bonds are in the same length range (between 2.2 and 2.5 Å) but bismuth-sulfur bonds are significantly longer (3.4 Å for Bi 2 O 2 S, <3 Å for Ln 2 O 2 S). Further works showed that bismuth can form several oxysulfides, leading to superconductive Bi 4 O 4 S 3 (Zhang et al, 2015) (containing both sulfide and sulfate ions) and to Bi 9 O 7.5 S 6 (Meng et al, 2015).…”

A Universal Positioning System for Coupling Characterization of SEM and AFM

“…The coupling characterization results of SiC and Bi 9 O 7.5 S 6 nanomaterials have achieved the expected results. The comprehensive information obtained from the same position in SEM and AFM provided critical clues in determining the growth mechanism of the SiC nanobelts [ 20 ] and photocatalytic properties of the Bi 9 O 7.5 S 6 nanoflake [ 21 ], respectively.…”