Three‐Dimensionally Ordered Gold Nanocrystal/Silica Superlattice Thin Films Synthesized via Sol–Gel Self‐Assembly

Abstract

Nanocrystals and their ordered arrays hold many important applications in fields such as catalysis, surface‐enhanced Raman spectroscopy based sensors, memory storage, and electronic and optical nanodevices. Herein, a simple and general method to synthesize ordered, three‐dimensional, transparent gold nanocrystal/silica superlattice thin films by self‐assembly of gold nanocrystal micelles with silica or organosilsesquioxane by spin‐coating is reported. The self‐assembly process is conducted under acidic sol–gel conditions (ca. pH 2), ensuring spin‐solution homogeneity and stability and facilitating the formation of ordered and transparent gold nanocrystal/silica films. The monodisperse nanocrystals are organized within inorganic host matrices as a face‐centered cubic mesostructure, and characterized by transmission electron spectroscopy and X‐ray diffraction.

Uniform mesoporous silica coated iron oxide nanoparticles as a highly efficient, nontoxic MRI T2 contrast agent with tunable proton relaxivities

“…A typical procedure for the synthesis of Fe 3 O 4 @mSiO 2 is depicted in Scheme . The surfactant CTAB serves as a phase transfer agent for oleic acid‐capped Fe 3 O 4 by coupling its alkyl chain to that of oleic acid through the hydrophobic van der Waals interactions, whilst the hydrophilic head group of CTAB facilitates the aqueous dispersion of Fe 3 O 4 NPs with thermodynamically defined bilayer structures . It is important to completely remove chloroform during the phase transfer process in order to obtain water‐dispersible Fe 3 O 4 –CTAB NPs without clustering.…”

Transitioning DNA‐Engineered Nanoparticle Superlattices from Solution to the Solid State

“…Silica encapsulation is a technique commonly used to stabilize inorganic nanoparticles of varying chemical compositions and morphologies against aggregation or oxidation 12–17. Applying sol‐gel techniques to this system, however, is synthetically non‐trivial due to the solubility and charged environment of the DNA‐nanoparticle assemblies.…”

Multifunctional Uniform Nanoparticles Composed of a Magnetite Nanocrystal Core and a Mesoporous Silica Shell for Magnetic Resonance and Fluorescence Imaging and for Drug Delivery

“…Cetyltrimethylammonium bromide (CTAB) serves not only as the stabilizing surfactant for the transfer of hydrophobic Fe 3 O 4 nanocrystals [10] to the aqueous phase [11] but also as the organic template for the formation of mesopores in the solgel reaction. [2] After removing the CTAB templates from the as-synthesized materials by heating them at reflux in acidic ethanol solution (pH 1.…”