Introductory Remarks

Metal nanoparticles (NPs) are attractive platforms for a variety of sensing applications, but their performance is often limited by the techniques employed to immobilize NPs at interfaces. Common methods yield randomly distributed NPs which exhibit nonideal behavior due to aggregation. Well-ordered NP arrays would not suffer from these limitations, 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 NP arrays. In this approach, metal NP arrays are straightforwardly fabricated via electrodeposition at the interface between a substrate electrode and a small (sub-μm) electrolyte-filled pipet. Experimental results will be presented which demonstrate this approach enables the fabrication of well-defined Au and Ag NP arrays with spatial control over NP location comparable with the terminal diameter of the pipet employed and straightforward control over the volume of each NP. Finite element simulations of mass transport within the SECCM geometry were utilized to explain the growth kinetics and NP morphology observed experimentally. Together, these results demonstrate probe-based electrochemical techniques such as SECCM can serve as effective tools for the fabrication of NP arrays to serve as platforms for biosensing applications.