Accéder au contenu
Merck

Electrically controlled nanoparticle synthesis inside nanopores.

Nano letters (2012-12-20)
Kimberly Venta, Meni Wanunu, Marija Drndić
RÉSUMÉ

From their realization just over a decade ago, nanopores in silicon nitride membranes have allowed numerous transport-based single-molecule measurements. Here we report the use of these nanopores as subzeptoliter mixing volumes for the controlled synthesis of metal nanoparticles. Particle synthesis is controlled and monitored through an electric field applied across the nanopore membrane, which is positioned so as to separate electrolyte solutions of a metal precursor and a reducing agent. When the electric field drives reactive ions to the nanopore, a characteristic drop in the ion current is observed, indicating the formation of a nanoparticle inside the nanopore. While traditional chemical synthesis relies on temperature and timing to monitor particle growth, here we observe it in real time by monitoring electrical current. We describe the dynamics of gold particle formation in sub-10 nm diameter silicon nitride pores and the effects of salt concentration and additives on the particle's shape and size. The current versus time signal during particle formation in the nanopore is in excellent agreement with the Richards growth curve, indicating an access-limited growth mechanism.

MATÉRIAUX
Référence du produit
Marque
Description du produit

Sigma-Aldrich
Silicon nitride, powder, ≥99.9% trace metals basis
Sigma-Aldrich
Silicon nitride, predominantly β-phase, ≤10micron primary particle size
Sigma-Aldrich
Silicon nitride, nanopowder, <50 nm particle size (spherical), ≥98.5% trace metals basis
Sigma-Aldrich
Silicon nitride, predominantly α-phase, ≤10 micron