Deterministic assembly of single emitters in sub-5 nanometer optical cavity formed by gold nanorod dimers on three-dimensional DNA origami

Zhi Zhao, Xiahui Chen, Jiawei Zuo, Ali Basiri, Shinhyuk Choi, Yu Yao, Yan Liu, Chao Wang

Research output: Contribution to journalArticlepeer-review

Abstract

Controllable strong interactions between a nanocavity and a single emitter is important to manipulating optical emission in a nanophotonic system but challenging to achieve. Herein a three-dimensional DNA origami, named as DNA rack (DR) is proposed and demonstrated to deterministically and precisely assemble single emitters within ultra-small plasmonic nanocavities formed by closely coupled gold nanorods (AuNRs). Uniquely, the DR is in a saddle shape, with two tubular grooves that geometrically allow a snug fit and linearly align two AuNRs with a bending angle < 10°. It also includes a spacer at the saddle point to maintain the gap between AuNRs as small as 2–3 nm, forming a nanocavity estimated to be 20 nm3 and an experimentally measured Q factor of 7.3. A DNA docking strand is designed at the spacer to position a single fluorescent emitter at nanometer accuracy within the cavity. Using Cy5 as a model emitter, a ∼ 30-fold fluorescence enhancement and a significantly reduced emission lifetime (from 1.6 ns to 670 ps) were experimentally verified, confirming significant emitter-cavity interactions. This DR-templated assembly method is capable of fitting AuNRs of variable length-to-width aspect ratios to form anisotropic nanocavities and deterministically incorporate different single emitters, thus enabling flexible design of both cavity resonance and emission wavelengths to tailor light-matter interactions at nanometer scale. [Figure not available: see fulltext.]

Original languageEnglish (US)
Pages (from-to)1327-1337
Number of pages11
JournalNano Research
Volume15
Issue number2
DOIs
StateAccepted/In press - 2021

Keywords

  • DNA origami
  • deterministic single emitter
  • nanorod dimer
  • optical coupling
  • plasmonic nanocavity
  • self-assembly

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Materials Science(all)
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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