@article{Zhao2022, 
author = {Zhi Zhao and Xiahui Chen and Jiawei Zuo and Ali Basiri and Shinhyuk Choi and Yu Yao and Yan Liu and Chao Wang},
title = {Deterministic assembly of single emitters in sub-5 nanometer optical cavity formed by gold nanorod dimers on three-dimensional DNA origami},
year = {2022},
journal = {Nano Research},
volume = {15},
number = {2},
pages = {1327-1337},
keywords = {DNA origami, self-assembly, deterministic single emitter, plasmonic nanocavity, nanorod dimer, optical coupling},
url = {https://www.sciopen.com/article/10.1007/s12274-021-3661-z},
doi = {10.1007/s12274-021-3661-z},
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.}
}