On-Demand Electrochemical Fabrication of Ordered Nanoparticle Arrays using Scanning Electrochemical Cell Microscopy

Abstract

Well-ordered nanoparticle arrays are attractive platforms for a variety of analytical applications, but the fabrication of such arrays is generally challenging. Here, it is demonstrated that scanning electrochemical cell microscopy (SECCM) can be used as a powerful, instantly reconfigurable tool for the fabrication of ordered nanoparticle arrays. Using SECCM, Ag nanoparticle arrays were straightforwardly fabricated via electrodeposition at the interface between a substrate electrode and an electrolyte-filled pipet. By dynamically monitoring the currents flowing in an SECCM cell, individual nucleation and growth events could be detected and controlled to yield individual nanoparticles of controlled size. Characterization of the resulting arrays demonstrate that this SECCM-based approach enables spatial control of nanoparticle location comparable with the terminal diameter of the pipet employed and straightforward control over the volume of material deposited at each site within an array. These results provide further evidence for the utility of probe-based electrochemical techniques such as SECCM as tools for surface modification in addition to analysis.

Optical Super‐Localisation of Single Nanoparticle Nucleation and Growth in Nanodroplets

“…This suggests that the electrodeposition produced a single Ag NP, in excellent agreement with an independent report at comparable experimental conditions, and particularly with the reported post mortem AFM/SEM images. [20] Herein, IRM provides the opportunity for operando monitoring of several descriptors of the growing NP over time. On each image of the time series, the optical feature is super-localized: its centroid coordinates are obtained, with ~10 nm precision (see details in SI section S4).…”

“…[11,12] Alternatively, the electrolyte meniscus, formed at the pipette orifice and in contact with an electrode surface, can act as a well-defined miniature electrochemical cell as in the scanning electrochemical cell microscopy (SECCM) technique, used for a range of electrodeposition or electrocrystallisation processes, and also for the controlled delivery of various types of nanocolloids onto specific locations on electrodes. [13][14][15][16][17][18][19][20][21][22] As well as investigating NP nucleation/growth processes, [22,23] SECCM [15] offers an elegant way to manufacture (electrochemically-driven) nanostructures, with optimal electrical connection between the structures and the substrate surface. [24] For example, using high reactant concentrations and high electrodeposition rates, it becomes possible to print 3D micro-to nanostructures with sub-100 nm resolution.…”

“…Indeed, SECCM was recently proposed as tool for fabricating on-demand arrays of individual Ag NPs. [20] In-situ optical microscopy, which is becoming increasingly powerful in electrochemistry, [25,26] would be a natural complement for such studies, by enabling operando monitoring of the electrodeposition process to reveal mechanistic aspects in real time. Herein, interference reflection microscopy (IRM), is used to synchronously observe events, occurring inside the SECCM droplet cell, during the electrodeposition of Ag NPs onto an indium tin oxide (ITO) electrode.…”

Electrocatalysis at Individual Colloidal Nanoparticles: A Quantitative Survey of Four Geometries via Electrochemical Cell Microscopy

“…The analysis of single nanoparticles using scanning electrochemical microscopy (SECM), − which employs an inlaid-disk electrode to probe reaction products in the vicinity of a sample, has been enabled through advancements in the fabrication of nanometer-scale probes. More recently, scanning electrochemical cell microscopy (SECCM), which utilizes electrolyte-filled pipets as electrochemical probes, has emerged as a powerful tool for studying a variety of electrochemical processes at individual nanostructures, including electrocatalysis, − ion transport, corrosion, , photoelectrochemistry, − and electrodeposition. , Both SECM and SECCM following scanning-based protocols which are capable of producing detailed images revealing spatial variations in reactivity across an electrode but can be severely limited in terms of sample throughput.…”

“…More recently, scanning electrochemical cell microscopy (SECCM), which utilizes electrolyte-filled pipets as electrochemical probes, has emerged as a powerful tool for studying a variety of electrochemical processes at individual nanostructures, including electrocatalysis, 28−35 ion transport, 36 corrosion, 37,38 photoelectrochemistry, 39−44 and electrodeposition. 45,46 Both SECM and SECCM following scanning-based protocols which are capable of producing detailed images revealing spatial variations in reactivity across an electrode but can be severely limited in terms of sample throughput. Recently, our group demonstrated targeted electrochemical cell microscopy (TECCM) as a high-throughput approach toward the electrochemical characterization of individual nanostructures.…”