Broad Band Enhancement of Light Absorption in Photosystem I by Metal Nanoparticle Antennas

Abstract

The photosystem I (PS I) protein is one of nature's most efficient light harvesting complexes and exhibits outstanding optoelectronic properties. Here we demonstrate how metal nanoparticles which act as artificial antennas can enhance the light absorption of the protein. This hybrid system shows an increase in light absorption and of circular dichroism over the entire absorption band of the protein rather than at the specific plasmon resonance wavelength of spherical metal nanoparticles (NPs). This is explained by broad-resonant and nonresonant field enhancements caused by metal NP aggregates, by the high dielectric constant of the metal, and by NP-PS I-NP antenna junctions which effectively enhance light absorption in the PS I.

Metallic Nanoparticles Coupled with Photosynthetic Complexes

“…While the interactions between plasmons and simple nanostructures such as organic dyes or semiconductor nanocrystals is relatively well described and understood, application of metallic nanoparticles to multipigment structures has started just recently (Carmeli, 2010;Govorov, 2008;Kim, 2011;Nieder, 2010). Light-harvesting complexes, or more generally, photosynthetic complexes, are quite appealing in this regard as they not only provide an interesting biomolecular system for studying plasmon effect on both the optical properties of pigments and the energy transfer between them, but also they could offer attractive potential application route in photovoltaics (Atwater & Polman, 2010;Mackowski, 2010).…”

Spatial modulation of light transmission through a single microcavity by coupling of photosynthetic complex excitations to surface plasmons

“…This phenomenon has been observed in organic semiconductor optical microcavities 3,[11][12][13] , sub-wavelength hole arrays 1,9,10 and molecules deposited on patterned surfaces 1 . The applications range from lasing 15 , LED's 12 , control of chemical reactions 11 and light harvesting 2,16,17 .…”

Optically active chiral Ag nanowires

“…These systems include metal NPs capped with various small chiral molecules, or biological macromolecules such as DNA [19−22], amino acids [23−28], peptides [29−31] teins [32,33]. Moreover, MacLachlan᾽s group used chiral nanocrystalline cellulose as hard template to prepare chiral nematic cellulose-silver [34] and -gold [35] NP composites.…”