Electrically Controlled Nanoparticle Synthesis inside Nanopores

Abstract

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.

Fabrication of faceted nanopores in magnesium

“…[8][9][10][11] While faceted nanopores can be potentially employed in rapid electrical detection and analysis of biomacromolecule with various shapes, the relevant investigation has been rarely reported. 14 In addition, Venta et al recently showed the synthesis of electrically controlled gold nanoparticles inside nanopores, 15 indicating that an individual nanopore can serve as a "nano-mold" regarding the synthesis of nanomaterials. Owing to the high-aspect-ratio, nanoparticles with different shapes and facets could exhibit drastically different electrical, 16,17 optical, 18,19 and catalytic 20,21 properties.…”

Fabrication of a single sub-micron pore spanning a single crystal (100) diamond membrane and impact on particle translocation

“…Highly sensitive electronics allows detection of very small changes in the conduction current, facilitating high-resolution size discrimination. The simplicity of the concept linked with the versatility of the method has led to the use of solid-state pores for a wide range of applications involving micro-and nanosized particles, [5][6][7][8][9] polymer chains [10] and proteins. [11][12][13][14] The capability of the technology to facilitate rapid and direct evaluation of individual DNA bases has made it particularly attractive for next-generation DNA sequencing.…”

Synthesis and investigation of the structure of nanocomposites based on nickel nanoparticles dispersed in a phthalocyanine matrix

“…At present, an intensive search has been carried out for low-cost effective methods of synthesizing such nanocomposites. In particular, the authors of [9][10][11][12][13] proposed a number of simple effective solid-phase chemical synthesis techniques with the features similar to those of the method used in the present study.…”