Gap-Dependent Coupling of Ag-Au Nanoparticle Heterodimers Using DNA Origami-Based Self-Assembly

© 2016 American Chemical Society. We fabricate heterocomponent dimers built from a single 40 nm gold and a single 40 nm silver nanoparticle separated by sub-5 nm gaps. Successful assembly mediated by a specialized DNA origami platform is verified by scanning electron microscopy and energy-dispersive X-ray characterization. Dark-field optical scattering on individual dimers is consistent with computational simulations. Direct plasmonic coupling between each nanoparticle is observed in both experiment and theory only for these small gap sizes, as it requires the silver dipolar mode energy to drop below the energy of the gold interband transitions. A new interparticle-spacing-dependent coupling model for heterodimers is thus required. Such Janus-like nanoparticle constructs available from DNA-mediated assembly provide an effective tool for controlling symmetry breaking in collective plasmon modes

Gap-Dependent Coupling of Ag-Au Nanoparticle Heterodimers Using DNA Origami-Based Self-Assembly

© 2016 American Chemical Society. We fabricate heterocomponent dimers built from a single 40 nm gold and a single 40 nm silver nanoparticle separated by sub-5 nm gaps. Successful assembly mediated by a specialized DNA origami platform is verified by scanning electron microscopy and energy-dispersive X-ray characterization. Dark-field optical scattering on individual dimers is consistent with computational simulations. Direct plasmonic coupling between each nanoparticle is observed in both experiment and theory only for these small gap sizes, as it requires the silver dipolar mode energy to drop below the energy of the gold interband transitions. A new interparticle-spacing-dependent coupling model for heterodimers is thus required. Such Janus-like nanoparticle constructs available from DNA-mediated assembly provide an effective tool for controlling symmetry breaking in collective plasmon modes

Artificial Photosynthesis: An Approach for a Sustainable Future

International audienceThe energy needs of humankind has experimented a sharp increase since the beginning of the Anthropocene due to a large increase in population and the evolution of our society’s lifestyle. Recent projections suggest that it will likely lead to a major crisis due to environmental issues associated with the increasing use of fossil fuel as major energy source, as well as due to a rapid dwindling of the classical and easily accessible fossil-fuels stocks. These issues require a quick response if the lifestyle adopted by our societies shall be sustained. Several solutions have been envisioned to tackle these problems, of which, the development of Artificial Photosynthetic systems is one of the most appealing. The field of artificial photosynthesis takes Nature itself as a source of inspiration, to propose alternative energy harvesting and storage strategies. This field of research not only aims at mimicking the main processes that permitted photosynthetic organisms to thrive and become the most successful autotrophs on earth, but as well at improving and optimizing these processes using synthetic materials. In this chapter, the underlying mechanisms that enable photosynthetic organisms to convert (and store) solar energy into a directly usable chemical energy will be discussed. Then it will be explained how these concepts can be extended to artificial systems and ultimately used to our own benefit