Rigid POSS Nanofiller Regulated the Interfacial Self‐assembly of Particles into 2D Monolayer Superlattice with Fixed Interparticle Spacing^†

Abstract

Comprehensive Summary Plasmonic superlattices of nanoparticles (NPs) possess unique “surface lattice resonances” properties that facilitates their wide applications in plasmonic sensing, photocatalysis, and nanoscale light manipulation. However, it is still challenging to manufacture superlattices with precisely controllable NPs distance and break the size limitation of NPs. Herein, we provided an effective strategy to construct NPs superlattices via shape‐persistent polyhedral oligosilsesquioxane (POSS) molecular nanoparticles govern interfacial assembly. As a nanoscale molecule with diameter of 1.5 nm, the POSS‐SH molecule provides sufficient rigid steric hindrance and hydrophobic effect for tailoring the uniformity and controllable distance between NPs in superlattices. Interestingly, synergistically with hydrophilic ligands of polyethylene glycol (PEG‐SH) with optimized ratio, the rigid POSS ligands can effectively regulate the distance between NPs in a fixed range of 2.3—2.8 nm, which is independent of ligands molecular weight and particle size. Furthermore, the effective approach can be universal to anisotropic NPs for manufacturing monolayer films with high NPs density. We believe this nanoscale molecule tailored interfacial self‐assembly strategy can effectively break the size of NPs and assembly obstacles for superlattice monolayer film. Additionally, the definite distance between NPs in superlattices can minimize optical energy attenuation and facilitates the applications such as surface‐enhanced Raman spectroscopy and photocatalysis.

2D superlattices via interfacial self-assembly of polymer-grafted Au nanoparticles

“…The liquid interface provides an ideal substrate for the diffusion and self-assembly of NPs because the fluidity of the liquid can avoid surface defects. 88,97–104 The essence of NP assembly is an adsorption process in which NPs are trapped on the phase interface. During the process, the NPs require an extra driving force to overcome high adsorption barriers and then be attracted to low-tension interfaces.…”

Gold Nanoparticles Coated with Silica Shells as High-Performance Fluorescence Nanoprobe

“…According to literature, 55 particles with Au−S bonds have a surface area of 0.214 nm 2 . By calculating the particle surface area, the number of Au−S bonds that can be placed on the surface of the nanoparticle in theory can be calculated, resulting in the amount of SH-PEG needed.…”

“…Au@SH-PEG Modification and Purification. Take 5 mL of Au NPs, add 10 mM 36.5 μL of SH-PEG solution to Au NPs (add 5 mL of modified 1/2 point position, add 2.5 mL of solution and 2.5 mL of water at 1/4 point position, add 1.25 mL of solution and 3.75 mL of water at 1/8 point position), mix ultrasound for 5 min, after 48 h of modification, 55 excess SH-PEG was removed by centrifugation twice at 10 280g after the end of the reaction and dispersed into 5 mL of ethanol. The modification methods for Au NRs, Au NBPs, Au NTs, and Ag NPs are the same.…”