Mass production of trimer rings consisting of 20 nm gold nanoparticles by using DNA template is demonstrated. Three kinds of DNA-monoconjugated gold nanoparticles are programmed to self-assemble into a trimer ring structure with nanoscale gaps through simple hybridization process. Self-assembled gold trimer rings are immobilized on a centimeter-scale quartz substrate to investigate their optical properties by the far-field transmission spectroscopy. Quantitative characterization of the gold trimer rings by atomic force microscope measurements reveals that 43% of gold nanoparticles keep forming the ring configuration on the substrate after the immobilizing process. In the far-field transmission spectroscopy, the trimer ring sample clearly exhibits two absorption dips in the visible spectrum, while monomer one has a single dip. The experimental results are in good agreement with the corresponding numerical simulations, proving that the unique spectral feature for the trimer ring arises from the hybridization of plasmon resonances of gold nanoparticles. The plasmonic responses of gold nanoparticle assemblies can be entirely controlled by designing DNA templates and thus may open up a novel approach for the realization of large-scale optical metamaterials.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films