Large patternable metal nanoparticle sheets by photo/e-beam lithography

Abstract

Techniques for micro/nano-scale patterning of large metal nanoparticle sheets can potentially be used to realize high-performance photoelectronic devices because the sheets provide greatly enhanced electrical fields around the nanoparticles due to localized surface plasmon resonances. However, no single metal nanoparticle sheet currently exists with sufficient durability for conventional lithographical processes. Here, we report large photo and/or e-beam lithographic patternable metal nanoparticle sheets with improved durability by incorporating molecular cross-linked structures between nanoparticles. The cross-linked structures were easily formed by a one-step chemical reaction; immersing a single nanoparticle sheet consisting of core metals, to which capping molecules ionically bond, in a dithiol ethanol solution. The ligand exchange reaction processes were discussed in detail, and we demonstrated 20 μm wide line and space patterns, and a 170 nm wide line of the silver nanoparticle sheets.

Durability improvements of two-dimensional metal nanoparticle sheets by molecular cross-linked structures between nanoparticles

“…In addition, the strengthened interactions between the nearest neighboring Ag nanoparticles by cross-linking DT16 molecules could result in improved mechanical toughness for the sonication process. 27) We finally examined the sheet durability for oxidation reaction using a remote photocatalyst. The intensities of the absorbance spectra of the AgMy and AgDT16 sheets were decreased with increasing reaction time as well as in the other durability tests (Fig.…”

“…Indeed, the sheet durability for organic solvents was reported to be improved by forming cross-linked structures with covalent bonds between nanoparticles. 27) In this study, we report improvements of the Ag nanoparticle sheet durability for thermal, organic solvent, and oxidation reactions by forming molecular cross-linked structures between Ag nanoparticles using 1,16-hexadecanedithiol (DT16). The two-side covalent bonds between DT16 and the nanoparticles due to the two reaction functions of the DT16, which are formed in the entire area of the sheet, are expected to cause the improvements.…”

Soft Bioelectronics Based on Nanomaterials

“…The lithographic techniques such as photolithography, − electron beam (e-beam) lithography, , and soft lithography, − followed by etching steps, are more advantageous in yielding the patterned nanomaterials from bulk ingredients. These techniques involve drawing desired patterns with a focused, high-energy light onto the photoresist, which serve as the etching barriers (Figure A­(v) and (vi)).…”