Deterministic assembly of single emitters in sub-5 nanometer optical cavity formed by gold nanorod dimers on three-dimensional DNA origami
Deterministic assembly of single emitters in sub-5 nanometer optical cavity formed by gold nanorod dimers on three-dimensional DNA origami
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DOI：
10.1007/s12274-021-3661-z
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发表时间：
2021-04
期刊：
影响因子：
9.9
通讯作者：
Zhi Zhao;Xiahui Chen;Jiawei Zuo;A. Basiri;Shinhyuk Choi;Yu Yao;Yan Liu;Chao Wang
中科院分区：
文献类型：
--
作者：
Zhi Zhao;Xiahui Chen;Jiawei Zuo;A. Basiri;Shinhyuk Choi;Yu Yao;Yan Liu;Chao Wang
纳米腔和单个发射器之间的可控强相互作用对于操纵纳米光子系统中的光发射是重要的，但实现起来具有挑战性。本文提出了一种三维DNA折纸，命名为DNA机架（DR），并证明了确定性和精确地组装在由紧密耦合的金纳米棒（AuNRs）形成的超小等离子体纳米腔中的单个发射体。独特的是，DR呈马鞍形，具有两个管状凹槽，其几何形状允许紧密配合并以< 10°的弯曲角度线性对齐两个AuNR。它还包括在鞍点处的间隔物，以保持AuNR之间的差距小至2-3 nm，从而形成估计为20 nm 3的纳米腔和7.3的实验测量的Q因子。DNA对接链被设计在间隔物处，以将单个荧光发射体以纳米精度定位在腔内。使用Cy 5作为模型发射体，实验验证了1.30倍的荧光增强和显着降低的发射寿命（从1.6 ns到670 ps），确认显着的发射体-腔相互作用。这种DR模板组装方法能够拟合可变长宽比的AuNR以形成各向异性纳米腔，并确定性地结合不同的单个发射器，从而使腔谐振和发射波长的灵活设计能够在纳米尺度上定制光-物质相互作用。
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 nm3and an experimentally measuredQfactor 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.