Arylthiolate-Protected Silver Quantum Dots

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• 作者：Matthew R. Branham ; Alicia D. Douglas ; Allan J. Mills ; Joseph B. Tracy ; Peter S. White ; Royce W. Murray
• 刊名：Langmuir
• 出版年：2006
• 出版时间：December 19, 2006
• 年：2006
• 卷：22
• 期：26
• 页码：11376 - 11383
• 全文大小：179K
• 年卷期：v.22,no.26(December 19, 2006)
• ISSN：1520-5827

文摘

This paper describes a new, organic-soluble 4-tert-butylbenzyl mercaptan (BBT) monolayer-protected silver cluster(AgBBT MPC) as the first example of a dissolved silver nanoparticle that exhibits quantized one-electron double layercharging (QDL) voltammetry. Polydisperse AgBBT MPCs made by two different synthetic protocols, but with similaraverage core diameters (2.1 nm), exhibit sharply differing electrochemistry and optical absorbance spectra. A two-phase procedure (organic/aqueous, termed Prep A-AgBBT) produced MPCs exhibiting a 475 nm surface plasmonabsorbance and QDL voltammetry. Neither property was seen for MPCs made by a single-phase procedure, termedPrep B-AgBBT. The difference is thought to reflect poor passivation to oxide formation in the latter Prep B procedure,which is supported by X-ray photoelectron spectroscopy results. Thermogravimetry, mass spectra, and electrochemistryresults suggest an average stoichiometric formula of Ag₁₄₀BBT₅₃, but transmission electron microscopy shows thatthe products are also polydisperse and include polycrystalline aggregates. Dry, cast films of both Ag MPC preparationson interdigitated array electrodes exhibit low electron hopping conductivity, compared to Au MPCs.