Three-Dimensional Plasmonic Nanocluster-Driven Light-Matter Interaction for Photoluminescence Enhancement and Picomolar-Level Biosensing

Plasmonic nanoparticle clusters promise to support unique engineered electromagnetic responses at optical frequencies, realizing a new concept of devices for nanophotonic applications. However, the technological challenges associated with the fabrication of three-dimensional nanoparticle clusters with programmed compositions remain unresolved. Here, we present a novel strategy for realizing heterogeneous structures that enable efficient near-field coupling between the plasmonic modes of gold nanoparticles and various other nanomaterials via a simple threedimensional coassembly process. Quantum dots embedded in the plasmonic structures display similar to 56 meV of a blue shift in the emission spectrum. The decay enhancement factor increases as the total contribution of radiative and nonradiative plasmonic modes increases. Furthermore, we demonstrate an ultracompact diagnostic platform to detect M13 viruses and their mutations from femtoliter volume, sub-100 pM analytes. This platform could pave the way toward an effective diagnosis of diverse pathogens, which is in high demand for handling pandemic situations.

Automated summary

Plasmonic nanoparticle clusters offer unique electromagnetic responses at optical frequencies and can be used for nanophotonic applications. This study presents a novel strategy for fabricating three-dimensional nanoparticle clusters with efficient coupling between gold nanoparticles and other nanomaterials. Quantum dots embedded in the clusters exhibit a blue shift in emission spectrum. In addition, an ultracompact diagnostic platform is demonstrated for detecting viruses and mutations.