The capability of assembling nanoparticles into a desired ordered pattern is a key to realize novel devices which are based not only on the unique properties of nanoparticles but also on the arrangements of nanoparticles. While two-dimensional arrays of nanoparticles have been successfully demonstrated by various techniques, a controlled way of building ordered arrays of three-dimensional (3D) nanoparticle structures remains challenging. We report that a variety of 3D nanoparticle structures can be formed in a controlled way based on the ion-induced focusing, electrical scaffold, and antenna effects from charged aerosols. Particle trajectory calculations successfully predict the whole process of 3D assembly. New surface enhanced Raman scattering substrates based on our 3D assembly were constructed as an example showing the viability of the present approach. This report extends the current capability of positioning nanoparticles on surface to another spatial dimension, which can serve as the foundation of future optical, magnetic, and electronic devices taking the advantage of multidimensions.

An ion-induced focusing mask under the simultaneous injection of ions and charged aerosols generates invisible electrostatic lenses around each opening, through which charged nanoparticles are convergently guided without depositing on the mask surface. The sizes of the created features become significantly smaller than those of the mask openings due to the focusing capability. It is not only demonstrated that material-independent nanoparticles including proteins can be patterned as an ordered array on any surface regardless of the conductive, nonconductive, or flexible nature of the substrate, but also that the array density can be increased. Highly sensitive gas sensors based on these focused nanoparticle patterns are fabricated via the concept.

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We report a general methodology for producing focused arrays of nanoparticles via electrodynamic focusing approach and controlling the inertial effect of charged aerosols. An important effect of particle inertia is identified and verified by performing detailed calculations of electric field induced particle motion and experimenting with electrosprayed nanoparticles. The controllability of focusing is demonstrated by changing the curvature of electric field lines.

Protein micro/nanoarrays with selectivity can be fabricated in a parallel way through the ion‐induced focusing of a charged aerosol form of the proteins. This method can also position protein nanoparticles onto the deep bottom surface within microchannels of a high aspect ratio. Particle trajectory calculations validate the experimental results. A new design of metal‐enhanced fluorescence substrate is successfully demonstrated.