Electrokinetic assembly of one-dimensional nanoparticle chains with cucurbit[7]uril controlled subnanometer junctions

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• One-dimensional nanoparticle chains are crucial for advanced plasmonic and electronic applications.
• Precisely controlling nanojunctions in these chains is essential for tuning their properties.
• Existing assembly methods often lack control over junction rigidity and size.

Purpose of the Study:

• To develop a method for assembling 1D gold nanoparticle chains with defined, rigid nanojunctions.
• To investigate the electrokinetic assembly process using cucurbit[n]uril molecules as nanojunctions.
• To analyze the plasmonic properties and growth mechanism of the assembled nanoparticle chains.

Main Methods:

• Electrokinetic assembly utilizing a nanoporous polycarbonate membrane.
• Employing cucurbit[n]uril (CB[n]) molecules to form 9 Å nanojunctions between gold nanoparticles.
• Controlling assembly parameters including applied voltage, nanoparticle/CB[n] concentration ratio, time, and temperature.
• Characterizing assembled structures using spatial structure and time-resolved plasmonics analysis.

Main Results:

• Successful assembly of 1D gold nanoparticle chains with fixed and rigid cucurbit[n]uril nanojunctions.
• Demonstration of electrokinetic control over the chain assembly process via applied voltage and concentration.
• Observation of a growth mechanism occurring within the membrane nanopores, confirmed by plasmonics analysis.
• Achieved nanojunctions with a precise size of 9 Å.

Conclusions:

• The presented electrokinetic strategy effectively produces 1D gold nanoparticle chains with controlled, rigid nanojunctions.
• The study elucidates the growth mechanism of nanoparticle chains within nanopores.
• This method offers a pathway for fabricating tailored nanostructures for plasmonic and electronic devices.