Effects of Irregular Bimetallic Nanostructures on the Optical Properties of Photosystem I from Thermosynechococcus elongatus

Imran Ashraf (1, 2) , Sepideh Skandary (1, 2) , Mohammad Khaywah (3, 4) , Michael Metzger (1, 2) , Alfred Meixner (1, 2) , Pierre-Michel Adam (3) , Marc Brecht (1, 2, 5)

1 Eberhard Karls Universität Tübingen = Eberhard Karls University of Tuebingen
2 Center for Light-Matter Interaction, Sensors & Analytics (LISA+)
3 LNIO - Laboratoire de Nanotechnologie et d'Instrumentation Optique
4 LU - Lebanese University [Beirut]
5 ZHAW - Zürich University of Applied Sciences

The fluorescence of photosystem I (PSI) trimers in proximity to bimetallic plasmonic nanostructures have been explored by single-molecule spectroscopy (SMS) at cryogenic temperature (1.6 K). PSI serves as a model for biological multichromophore-coupled systems with high potential for biotechnological applications. Plasmonic nanostructures are fabricated by thermal annealing of thin metallic films. The fluorescence of PSI has been intensified due to the coupling with plasmonic nanostructures. Enhancement factors up to 22.9 and 5.1 are observed for individual PSI complexes coupled to Au/Au and Ag/Au samples, respectively. Additionally, a wavelength dependence of fluorescence enhancement is observed, which can be explained by the multichromophoric composition of PSI.

Keywords: bimetallic nanostructures; plasmonic; thermal annealing; photosystem I; single-molecule spectroscopy; fluorescence emission enhancement

Domains: Optics / Photonic; Micro and nanotechnologies/Microelectronics

Imran Ashraf, Sepideh Skandary, Mohammad Khaywah, Michael Metzger, Alfred Meixner, et al.. Effects of Irregular Bimetallic Nanostructures on the Optical Properties of Photosystem I from Thermosynechococcus elongatus. Light-Harvesting Processes LHP 2015, Mar 2015, Bad Staffelstein, Germany. ⟨10.3390/photonics2030838⟩. ⟨hal-02484586⟩