Advanced Functional Materials

Cover image for Vol. 25 Issue 28

17_17b/2007Inside Front Cover: Surfactant-Assisted Preparation of Novel Layered Silver Bromide-Based Inorganic/Organic Nanosheets by Pulsed Laser Ablation in Aqueous Media (Adv. Funct. Mater. 17/2007)

Novel layered AgBr-based inorganic/organic nanosheets can be prepared by pulsed laser ablation of Ag in an aqueous solution of cetyltrimethylammonium bromide (CTAB), report Takeshi Sasaki, Naoto Koshizaki, and co-workers on p. 3554. The green image shows the distribution of carbon in a nanosheet deposited on a holey carbon film. The nanosheet structure is composed of anionic bromine-rich AgBr inorganic layers and cationic surfactant layers (CTA+) with an interdigitated bilayer arrangement.

A novel layered AgBr-based inorganic/organic nanocomposite was prepared by pulsed laser ablation (PLA) of Ag in aqueous media in the presence of cetyltrimethylammonium bromide (CTAB), and the formation mechanism of two-dimensional nanosheet was discussed. TEM observations indicate that the obtained AgBr-based inorganic/organic nanocomposite possesses a well-defined two-dimensional shape and that the size of the nanosheet can be changed with the surfactant concentration in the solution. X-ray diffraction (XRD) pattern was composed of a series of peaks that could be indexed to (00l) reflections of a layered structure, and the basal spacing of 20.0 Å indicated that the surfactant was included between the AgBr interlayers in an interdigitated bilayer arrangement. In contrast, a layered inorganic/organic nanocomposite cannot be formed at a CTAB concentration lower than the critical micelle concentration (CMC). Based on our detailed investigation, we proposed the nanocomposite formation process, that is, that negatively charged inorganic AgBr was produced by a strong reaction between the ablated Ag species and the bromide ions, which are concurrently assembling with cationic surfactant molecules controlled by the charge-matching mechanism.

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