Evolutionary Optimized, Monocrystalline Gold Double Wire Gratings as a Novel SERS Sensing Platform

Amro O. Sweedan, Mariela J. Pavan, Enno Schatz, Henriette Maaß, Ashageru Tsega, Vered Tzin, Katja Höflich, Paul Mörk, Thorsten Feichtner, Muhammad Y. Bashouti

Research output: Contribution to journalArticlepeer-review

Abstract

Achieving reliable and quantifiable performance in large-area surface-enhanced Raman spectroscopy (SERS) substrates poses a formidable challenge, demanding signal enhancement while ensuring response uniformity and reproducibility. Conventional SERS substrates often made of inhomogeneous materials with random resonator geometries, resulting in multiple or broadened plasmonic resonances, undesired absorptive losses, and uneven field enhancement. These limitations hamper reproducibility, making it difficult to conduct comparative studies with high sensitivity. This study introduces an innovative approach that addresses these challenges by utilizing monocrystalline gold flakes to fabricate well-defined plasmonic double-wire resonators through focused ion-beam lithography. Inspired by biological strategy, the double-wire grating substrate (DWGS) geometry is evolutionarily optimized to maximize the SERS signal by enhancing both excitation and emission processes. The use of monocrystalline material minimizes absorption losses and ensures shape fidelity during nanofabrication. DWGS demonstrates notable reproducibility (RSD = 6.6%), repeatability (RSD = 5.6%), and large-area homogeneity > 104 µm2. It provides a SERS enhancement for sub-monolayer coverage detection of 4-Aminothiophenol analyte. Furthermore, DWGS demonstrates reusability, long-term stability on the shelf, and sustained analyte signal stability over time. Validation with diverse analytes, across different states of matter, including biological macromolecules, confirms the sensitive and reproducible nature of DWGSs, thereby establishing them as a promising platform for future sensing applications.

Original languageAmerican English
JournalSmall
DOIs
StateAccepted/In press - 1 Jan 2024

Keywords

  • SERS substrate
  • double-resonance
  • focused ion-beam lithography
  • grating nanostructures
  • monocrystalline gold flakes
  • plasmonic resonator
  • surface-enhanced Raman spectroscopy

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • Engineering (miscellaneous)
  • Biotechnology
  • General Materials Science
  • Biomaterials

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