Attomolar level detection of Raman molecules with hierarchical silver nanostructures including tiny nanoparticles between nanosized gaps generated in silver petals

Anirban Dandapat, Tae Kyung Lee, Yiming Zhang, Sang Kyu Kwak, Eun Chul Cho, Dong Hwan Kim

Research output: Contribution to journalArticle

10 Scopus citations


We developed a route for synthesizing Ag nanostructures with tunable morphologies for ultrasensitive surface-enhanced Raman spectroscopy. Through the consecutive addition of three reducing agents (i.e., 4-mercaptobenzoic acid, trisodium citrate, and ascorbic acid) to an aqueous solution of silver nitrate, hierarchical flower-like Ag nanostructures were produced. The nanostructures had Ag petals in which nanosized gaps were generated, and small Ag nanoparticles were incorporated within the gaps. Theoretically, the nanostructures exhibited highly enhanced electric fields in the outer-shell regions where the small Ag nanoparticles were densely located. Combining the enhanced field effect with resonance effect of a Raman-active molecule (methylene blue) at a specific wavelength, measurable Raman signals were obtained at concentrations as low as 100 attomolar (10-16 M; corresponding to 10-21 mol). Key factors were discussed for the synthesis of the Ag nanostructures while finely controlling the morphologies of hierarchical Ag nanostructures, thereby modulating the intensity of surface-enhanced resonance Raman spectroscopy (SERRS) signals. Therefore, this synthetic method produces highly promising nanostructures for SERRS-based applications.

Original languageEnglish
Pages (from-to)14793-14800
Number of pages8
JournalACS Applied Materials and Interfaces
Issue number27
Publication statusPublished - 2015 Jul 15



  • morphology tuning
  • nanoparticles incorporated branches
  • silver nanostructures
  • ultrasensitive detection

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