Report

Teaser, summary, work performed and final results

Periodic Reporting for period 3 - Dynamic Nano (Dynamic Nanoplasmonics)

Teaser

In my project, I would like to develop a new generation of dynamic nanoplasmonic building blocks for biology, chemistry, and materials science. These plasmonic building blocks either can exhibit dynamic structural changes themselves or can be integrated with functional...

Summary

In my project, I would like to develop a new generation of dynamic nanoplasmonic building blocks for biology, chemistry, and materials science. These plasmonic building blocks either can exhibit dynamic structural changes themselves or can be integrated with functional materials, where dynamic events take place. I will utilize both bottom-up and top-down nanotechniques to advance the perspective of plasmonics towards synthetic plasmonic machinery as well as on-chip dynamic plasmonic devices with both tailored optical response and active functionality. With such plasmonic building blocks, long-standing questions in protein dynamics, chiral sensing, dynamic light matter interaction, gas-phase catalysis, and phase transitions on the nanoscale will be addressed. My proposed methods will allow for unprecedented resolution when optically disseminating dynamic behavior and revolutionary multidisciplinary experiments that were not possible to be performed before.

Work performed

In the scenario of dynamic nanoplasmonics with reconfigurability, we have utilized an advanced bottom-up method, namely, structural DNA technology, to create reconfigurable plasmonic building blocks including plasmonic walkers on 2D and 3D DNA origami platforms (Nature Communications 6, 8102 (2015); Nano Lett. 15, 8392 (2015)) as well as plasmonic switches that can translate molecular motion into reversible optical function changes (Nature Communications 7, 10591 (2016)). We have also achieved plasmonic chiral metasurfaces which possess complex toroidal geometry (JACS 138, 5495 (2016)).

In the scenario of dynamic nanoplasmonics with functionality, we have demonstrated a new class of hybrid plasmonic metamolecules composed of magnesium and gold nanoparticles. The plasmonic chirality from such plasmonic metamolecules can be dynamically controlled by hydrogen in real time without introducing macroscopic structural reconfiguration (Nano Lett. 16, 1462 (2016)).

Final results

In the scenario of dynamic nanoplasmonics with reconfigurability, we have developed the first plasmonic walkers with programmable and dynamic optical response. A plasmonic walker consists of multiple metal nanoparticles rationally organized by DNA assembly. Gold nanoparticles are modified by thiolated DNA strands which serve as their ‘feet’ to execute nanometer steps following a pre-defined route on a DNA origami track. Compared to the reconfigurable plasmonic building blocks, a plasmonic walker behaves more like a movable optical probe, which can perform nanometer walking towards its target of interest. Simultaneously, the DNA origami track can serve as a template to accurately position single nano-objects at particular sites, including metal nanoparticles for plasmonic coupling, chiral molecules, e.g., proteins for chiral sensing, as well as quantum emitters, e.g., quantum dots, dye molecules, and nanodiamonds for plasmon-enhanced emission. Consequently, studies of dynamic light matter interaction within nanometer accuracy become possible.

In the scenario of dynamic nanoplasmonics with functionality, we have created complex and hybrid plasmonic antennas using advanced nanolithography to study the dynamic behavior of phase-transition nanomaterials. In paticular, we have demonstrated a new class of hybrid plasmonic metamolecules composed of magnesium and gold nanoparticles. The plasmonic chirality from such plasmonic metamolecules can be dynamically controlled by hydrogen in real time without introducing macroscopic structural reconfiguration. We experimentally investigate the switching dynamics of the hydrogen-regulated chiroptical response in the visible spectral range using circular dichroism spectroscopy. In addition, energy dispersive X-ray spectroscopy is used to examine the morphology changes of the magnesium particles through hydrogenation and dehydrogenation processes. Our study can enable plasmonic chiral platforms for a variety of gas detection schemes by exploiting the high sensitivity of circular dichroism spectroscopy.