1. Role of Halides in the Ordered Structure Transitions of Heated Gold Nanocrystal Superlattices
- Author
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Yixuan Yu, Michael R. Rasch, Brian W. Goodfellow, Brian A. Korgel, Detlef-M. Smilgies, and Christian A. Bosoy
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Superlattice ,Halide ,Nanotechnology ,Surfaces and Interfaces ,Condensed Matter Physics ,Chloride ,Article ,Gold nanocrystal ,chemistry.chemical_compound ,Crystallography ,chemistry ,Nanocrystal ,Pulmonary surfactant ,Bromide ,Nano ,Electrochemistry ,medicine ,General Materials Science ,Spectroscopy ,medicine.drug - Abstract
Dodecanethiol-capped gold (Au) nanocrystal superlattices can undergo a surprisingly diverse series of ordered structure transitions when heated (Goodfellow, B. W.; Rasch, M. R.; Hessel, C. M.; Patel, R. N.; Smilgies, D.-M.; Korgel, B. A. Nano Lett. 2013, 13, 5710-5714). These are the result of highly uniform changes in nanocrystal size, which subsequently force a spontaneous rearrangement of superlattice structure. Here, we show that halide-containing surfactants play an essential role in these transitions. In the absence of any halide-containing surfactant, superlattices of dodecanethiol-capped (1.9-nm-diameter) Au nanocrystals do not change size until reaching about 190-205 °C, at which point the gold cores coalesce. In the presence of halide-containing surfactant, such as tetraoctylphosphonium bromide (TOPB) or tetraoctylammounium bromide (TOAB), the nanocrystals ripen at much lower temperature and superlattices undergo various ordered structure transitions upon heating. Chloride- and iodide-containing surfactants induce similar behavior, destabilizing the Au-thiol bond and reducing the thermal stability of the nanocrystals. more...
- Published
- 2015
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