Highly Conducting, n-Type Bi12O15Cl6 Nanosheets with Superlattice-like Structure

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• 作者：Yoon Myung ; Fei Wu ; Sriya Banerjee ; Andreea Stoica ; Hongxia Zhong ; Seung-Soo Lee ; John Fortner ; Li Yang ; Parag Banerjee
• 刊名：Chemistry of Materials
• 出版年：2015
• 出版时间：November 24, 2015
• 年：2015
• 卷：27
• 期：22
• 页码：7710-7718
• 全文大小：720K
• ISSN：1520-5002

文摘

Modulating the type and magnitude of electrical conductivity remains a basic requirement for a semiconductor鈥檚 widespread acceptability and use. Here, we convert nanosheets of BiOCl, a V鈥揤I鈥揤II ternary semiconductor, to an oxygen-rich Bi₁₂O₁₅Cl₆ phase. In the process, the intrinsic conductivity switches from p-type to n-type. The phase change is achieved using a vacuum annealing step at 500 掳C for 1 h. BiOCl nanosheets convert to the Bi₁₂O₁₅Cl₆ phase via volatilization of BiCl₃ resulting in a unique superlattice like structure with a periodicity of 1.48 nm. Correspondingly, the band gap decreases from 3.41 to 2.48 eV from the raising of the valence band edge. Activation energy for electrical conductivity reduces from 862 meV for BiOCl to 778 meV for Bi₁₂O₁₅Cl₆, and a corresponding photoconductivity increase of 80脳 is observed. Density functional theory calculations predict changes to the valence band and increase in the Fermi level toward the conduction band edge for the Bi₁₂O₁₅Cl₆ nanosheets鈥攊n accordance with experimental data. The availability of both p- and n-type ternary semiconducting systems widen the application base for Bi鈥揙鈥揅l based materials.