Size-Controlled Synthesis of Sub-10-nanometer Citrate-Stabilized Gold Nanoparticles and Related Optical Properties.

By J. Piella, N. Bastus, V. Puntes. 2016

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Highly monodisperse, biocompatible and functionalizable sub-10-nm citrate-stabilized gold nanoparticles (Au NPs) have been synthesized following a kinetically controlled seeded-growth strategy. The use of traces of tannic acid together with an excess of sodium citrate during nucleation is fundamental in the formation of a high number (7 × 1013 NPs/mL) of small ∼3.5 nm Au seeds with a very narrow distribution. A homogeneous nanometric growth of these seeds is then achieved by adjusting the reaction parameters: pH, temperature, sodium citrate concentration and gold precursor to seed ratio. We use this method to produce Au NPs with a precise control over their sizes between 3.5 and 10 nm and a versatile surface chemistry allowing studying the size-dependent optical properties in this transition size regime lying between clusters and nanoparticles. Interestingly, an inflection point is observed for Au NPs smaller than 8 nm in which the sensitivity of the localized surface plasmon resonance (LSPR) peak positio...

Subfields: Electronic, Optical and Magnetic Materials, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/72d521d499287e2a9ca6613262f8d155a2c24d68