Photocatalytic, structural and optical properties of mixed anion solid solutions Ba₃Sc_2−xIn_xO₅Cu₂S₂ and Ba₃In₂O₅Cu₂S_2−ySe_y

Abstract

Nine members of two contiguous solid solutions, Ba3Sc2-xInxO5Cu2S2 and Ba3In2O5¬Cu2S2-ySey (x, y = 0. 0.5, 1, 1.5 and 2), were synthesised at temperatures between 800 °C and 900 °C by...

Fast lithium-ion conductivity in the ‘empty-perovskite’ n = 2 Ruddlesden–Popper-type oxysulphide Y2Ti2S2O5

“…We speculate that this mechanism may contribute to the excellent photocatalytic activity of Y 2 Ti 2 S 2 O 5 and Sm 2 Ti 2 S 2 O 5 . 52,83 With advances in the design 84 and modular synthesis of layered mixed-anion semiconductors, 85 it may be possible to employ this strategy for the design of improved photocatalysts that efficiently separate charges and maximise carrier lifetimes.…”

Investigation of factors affecting the stability of compounds formed by isovalent substitution in layered oxychalcogenides, leading to identification of Ba3Sc2O5Cu2Se2, Ba3Y2O5Cu2S2, Ba3Sc2O5Ag2Se2 and Ba3In2O5Ag2Se2

“…In addition to the four novel Ba 3 M 2 O 5 M′ 2 Ch 2 compounds discussed above, there are a further four that have been previously reported: Ba 3 Sc 2 O 5 Cu 2 S 2 , Ba 3 InO 5 Cu 2 S 2 , Ba 3 In 2 O 5 Cu 2 Se 2 , and Ba 3 Y 2 O 5 Ag 2 Se 2 , although for the final example only the lattice parameters have been provided, with no further structural details. 3,4,9 These stable layered oxychalcogenides provide a suite of homologous materials with which to compare our novel compounds, in the discussion below. We did attempt to repeat the synthesis of Ba 3 Y 2 O 5 Ag 2 Se 2 for this work but found the material to be extremely air sensitive and were unable to collect diffraction data of sufficient quality to refine the atomic positions in order to provide a detailed structural analysis, however we are able to confirm the reported lattice parameters (ESI,† Fig.…”

“…Three of these band structures have been previously reported (Ba 3 Sc 2 O 5 Cu 2 S 2 , Ba 3 In 2 O 5 Cu 2 S 2 and Ba 3 In 2 O 5 Cu 2 Se 2 ) and are reproduced here for completeness, marked with an asterisk. 3,4 The values of m * hole in the [Cu 2 Ch 2 ] 2− /[Ag 2 Se 2 ] 2− planes are found at Γ – X and Γ – N and are relatively low. The values for each sample are reported in Table 2, but across all samples the intraplane hole masses are found in the range 0.37 m e to 0.65 m e , with lower values for selenide containing materials and higher values for the sulfide compounds.…”

“…This confirms that Ba 3 Sc 2 O 5 Ag 2 Se 2 is a visible light photocatalyst, comparable to other layered oxychalcogenides tested using the same procedure, with a similar rate to Ba 3 In 2 O 5 Cu 2 S 2 (14.5% dye degradation in three hours), but lower than Ba 3 Sc 2 O 5 Cu 2 S 2 (27.0% degradation). 4…”

“…The mixed-anion layered material Sr 3 Sc 2 O 5 Cu 2 S 2 has been identified as a promising p-type transparent conductor, having an unusually high hole mobility, 1,2 which subsequently prompted a computational search for further p-type conductors adopting this structure. 3 Isostructural oxysulfides, Ba 3 Sc 2 O 5 Cu 2 S 2 and Ba 3 In 2 O 5 Cu 2 S 2 , have been found to be photocatalysts, 4 in common with other layered oxysulfides. 5,6 The 32522 structure of Sr 3 Sc 2 O 5 Cu 2 S 2 – the designation derived from the ratio of the ions – adopted by these compounds is part of a broader class of oxychalcogenides with isostructural copper or silver chalcogenide anti-litharge layers, separated by oxide layers with varying thickness and co-ordination, often adopting a fragment of the perovskite structure.…”