A systems approach towards the stoichiometry-controlled hetero-assembly of nanoparticles

Abstract

A central theme in nanotechnology is to advance the fundamental understanding of nanoscale component assembly, thereby allowing rational structural design that may lead to materials with novel properties and functions. nanoparticles (nPs) are often regarded as 'artificial atoms', but their 'reactions' are not readily controllable. Here, we demonstrate a complete nanoreaction system whereby colloidal nPs are rationally assembled and purified. Two types of functionalized gold nPs (A and B) are bonded to give specific products AB, AB 2 , AB 3 and AB 4 . The stoichiometry control is realized by fine-tuning the charge repulsion among the B-nPs. The products are protected by a polymer, which allows their isolation in high purity. The integration of hetero-assembly, stoichiometry control, protection scheme and separation method may provide a scalable way to fabricate sophisticated nanostructures.

Colloidal β-KYF4:Yb3+,Er3+/Tm3+nanocrystals: tunable multicolor up-conversion luminescence from UV to NIR regions

“…Compared with traditional fluorescent materials, UCNCs exhibit excellent photostability, continuous emission capability, and sharp multi-peak line emission [5][6][7][8] . In particular, lanthanide-doped UCNCs have the remarkable ability to transfer its excitation energy states of lanthanide ions (sensitizer ion) to a neighboring ion (activator ion) to emit efficient emissions by anti-stokes process 1,[9][10][11] .…”

Tuning and Maximizing the Single-Molecule Surface-Enhanced Raman Scattering from DNA-Tethered Nanodumbbells

“…3,18 Although very high EF values up to 10 13 or 10 14 have been reported, it was shown that an EF value of 10 7 to 10 8 may be large enough even for single-molecule detection, and more important issues are to synthesize the hot SERS nanostructures with high structural reproducibility on the nanometer scale and to obtain a narrow distribution of the high EF values in a reliable fashion. 19À24 Various synthetic and fabrication methods generate nanoparticle-based clusters, and plasmonic nanogaps are formed via salt-induced colloidal agglomeration, 25À27 thiol linker-based gold clusters, 28 dimers or multimers using B functional organic molecules, 29,30 polymer encapsulation, 31,32 hybridization of DNA-modified gold nanoparticles, 33,34 particle etching, 35 electrostatic control, 36 self-assembly of polymer film 37 or a lithographic technique. 38 However, the SERS-based single-molecule detection is still controversial with respect to practicality in use and reliability in data, and a controllable <1 nm plasmonic gap is often needed to generate the ultrahigh EF values with reproducibility and to detect a Raman signal from a single molecule.…”

Metal-Based Composite Nanomaterials

“…The reaction toolkit applies solid-state nanoparticle analogues of chemoselective reactions, regiospecificity, coupling reactions, and molecular substituent effects to the construction of exceptionally complex composite nanoparticle oligomers. The emerging advances in nanoparticle separation and purification could further improve yield and homogeneity (Latham et al 2005;Beveridge et al 2009Beveridge et al , 2011, and the continued development of new classes of reactions, including orthogonal reaction schemes (Leonard et al 2009;Wang et al 2010b), could further expand these synthesis-by-design capabilities.…”