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. 2020 Sep 22;14(9):11009-11016.
doi: 10.1021/acsnano.0c04793. Epub 2020 Aug 12.

Nanocube Imprint Lithography

Affiliations

Nanocube Imprint Lithography

Harshal Agrawal et al. ACS Nano. .

Abstract

In recent years, imprint lithography has emerged as a promising patterning technique capable of high-speed and volume production. In this work, we report highly reproducible one-step printing of metal nanocubes. A dried film of monocrystalline silver cubes serves as the resist, and a soft polydimethylsiloxane stamp directly imprints the final pattern. The use of atomically smooth and sharp faceted nanocubes facilitates the printing of high-resolution and well-defined patterns with face-to-face alignment between adjacent cubes. It also permits digital control over the line width of patterns such as straight lines, curves, and complex junctions over an area of several square millimeters. Single-particle lattices as well as three-dimensional nanopatterns are also demonstrated with an aspect ratio up to 5 in the vertical direction. The high-fidelity nanocube patterning combined with the previously demonstrated epitaxial overgrowth can enable curved (single) crystals from solution at room temperature or highly efficient transparent conductors.

Keywords: PDMS; assembly; colloidal ink; large-scale printing; nanocubes; patterning.

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Conflict of interest statement

The authors declare no competing financial interest.

Figures

Figure 1
Figure 1
Schematic of the nanocube imprint lithography process.
Figure 2
Figure 2
A variety of printed patterns of Ag nanocubes demonstrating the potential of nanocube imprint lithography. (a and b) Circles of 1 and 2 μm radii of curvature, respectively. (c–f) Arcs of 2 μm radius of curvature with a line width of 1, 2, 3, and 4 cubes, respectively. (g) Cubes printed in a grid pattern with a pitch of 5 μm. (h) Gratings of cubes with a pitch of 1.4 μm. (i) An acute angle turn. (j) A four-way junction. (k) A three-way junction. (l) Sharp 90° turn (corner). (m) Cubic and (n) hexagonal superlattices of Ag cubes. All scale bars are 1 μm in length.
Figure 3
Figure 3
Potential for large-scale imprinting. (a) Optical micrograph of arrays of circles of Ag cubes. (b) Optical micrograph of gratings of commercially available 50 nm silica spheres. (c) Optical image of the printed grid of Ag nanocubes. The inset depicts the Si substrate from which the optical image was taken, and the center of the substrate is reflecting the bright colors because of the diffraction of light due to the printed grid.
Figure 4
Figure 4
Patterns of (a) a curve and (b) a line with a maximum aspect ratio of 5 in the z-direction. (c, d) 3D patterns assembled out of Ag cubes. All scale bars are 1 μm in length.

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