Pyroelectric Bi<sub>5-x</sub>(Bi<sub>2</sub>S<sub>3</sub>)<sub>39</sub>I<sub>12</sub>S: Fibonacci Superstructure, Synthesis Options and Solar Cell Potential

• 作者: Hans Hermann Otto
• 来源期刊: 凝固态物理国际期刊(英文)
• 学科: 化学
• 关键词: Hexagonal Bismuth Sulfide Iodide SUPERSTRUCTURE Sub-Cell FIBONACCI Numbers Sequence Pyroelectricity Crystal Growth Nano-Rods Completely Inorganic Solar Cell Twin-Cell Photocatalyst
• 年，卷（期）: 2015,（2）
• 页码范围: 66-77
• 页数: 12页
• 分类号: O6

摘要

Previously, synthetic hexagonal bismuth sulfide iodide (polar space group P63, a = 15.629(3) ?, c = 4.018(1) ?, Z = 2) has been described by the rather unsatisfactory fractional formula Bi19/3IS9 [1] 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E0000005F005200650066003400310037003600350038003400370039000000 -[3] 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E0000005F005200650066003400310037003600350038003400370036000000 . A redetermination of the structure using old but reliable photographic intensity data indicated the presence of additional split positions and reduced atomic occupancies. From the observed pattern of this “averaged” structure a consistent model of a superstructure with lattice parameters of a' = √13·a = 56.35(1) ?, c' = c, and a formula Bi5-x(Bi2S3)39I12S emerged, with 2 formula units in a cell of likewise P63 space group. Structural modulation may be provoked by the space the lone electron pair of Bi requires. When Bi on the 0, 0, z position of the “averaged” cell is transferred to two general six-fold sites and one unoccupied twofold one of the super-cell, more structural stability is guaranteed due to compensation of its basal plane dipole momentum. Owing to the limited intensity data available, more details of the superstructure are not accessible yet. Some physical properties and solar cell application are discussed together with suggestions of ambient temperature synthesis routes of c-axis oriented nano-rod sheets.