The institute
FEMTO's news

You are here

Understanding energy transfers during photosynthesis

Using three pigments manipulated by scanning tunneling microscopy, researchers from IPCMS and FEMTO-ST are studying energy transfers between molecules to gain a finer understanding of the photosynthesis mechanism in plants. This work is published in Nature Chemistry.

Photosynthesis allows plants to transform solar energy into chemical energy necessary for their growth. This mechanism is carried out by a complex assembly of organic molecules, the pigments, whose purpose is to collect, transport and transform solar energy. The successive energy transfers are made by jumps between neighboring molecules, but also via collective phenomena, potentially coherent, involving simultaneously a larger number of pigments. To better understand these effects, it is necessary to unravel these pigment assemblies in order to study separately the role of each active unit in photosynthesis. In this study, using a "bottom-up" approach, the researchers use model pigments isolated from each other, which they then reassemble to form the first functional bases capable of reproducing the energy transfer mechanisms involved in photosynthesis.

Three different pigments are thus deposited by evaporation on a surface in very small quantities, in order to have molecules that are far from each other. A scanning tunneling microscope is used to visualize each of the pigments, and then to manipulate them one by one, in order to form structures close to the elementary bricks observed in natural photosynthetic systems. A first pigment, called donor, absorbs an excitation. A second pigment acts as an intermediary which, depending on its nature, increases or reduces the efficiency of the energy transfer. A third pigment, acceptor, transforms this energy into photon. In the experiment, the scanning tunneling microscope is used to emit an electron to generate a local excitation of one of the pigments, which allows to reproduce the mechanism of absorption of a photon by a pigment of the plant. The energy received by the acceptor is converted into photons rather than chemical energy. The reaction is thus a reverse photosynthesis, with the capture of an electron leading to the release of a photon, but the energy transfers take place in the same way.

This approach allows to control the distance and orientation between the pigments with a precision close to the distance between two atoms and the researchers were able to highlight the role played by interactions in the energy transfer mechanism. These interactions are either long range, such as dipole-dipole, or short range, the latter depending on a mechanism, called exchange, specific to quantum physics. This study also shows that, depending on its chemical nature, the intermediate pigment can play a role of active relay of the excitation, amplify the energy transfer between two molecules without directly intervening in the process, or partially block it.

Thus, by using elementary bricks similar to those used by the plant to transport and convert solar energy, the researchers have developed a platform to reproduce the fine mechanisms of photosynthesis and, in the near future, elucidate them.

Schematic of the experiment where the tip of a scanning tunneling microscope (in gray) is used to excite an assembly of three pigments close to those involved in plant photosynthesis. The excitation generated in the blue pigment is transferred, sequentially, to the red pigment where the energy is transformed into photon (top). Hyper-resolved fluorescence image of the three pigments (bottom).    (Credit: Guillaume Schull, IPCMS)

 

DOI : 10.1038/s41557-021-00697-z.

Contact at FEMTO-ST : Frédéric Cherioux, CNRS Senior researcher

See the article published on the INP CNRS website

  • CNRS "Proof by Image" competition

     Discover the selection of the 20 images selected by the CNRS, one of which is presented by FEMTO-ST, and vote for the "audience award" photo.

    Read more
  • Imaging quantum interference of entangled photon pairs of extremely high dimensionality

    Researchers from the Optics Department have developed an imaging device allowing the spatial and temporal resolution of the phenomenon of quantum interference between pairs of entangled photons of extremely high dimensionality.

    Read more
  • Fei GAO Receives IEEE J.D. Irwin Early Career Award

    As a member of the SHARPAC team and Deputy Director of FEMTO-ST, Fei Gao has been recognized by the IEEE IES Society for his outstanding work in improving the reliability of hydrogen electric powertrains.

    Read more
  • Daniel HISSEL, winner of the CNRS 2020 Innovation Medal

    Full professor at the University of Franche-Comté, researcher at FEMTO-ST Institute and co-founder of a start-up on efficient hydrogen fuel cells, Daniel HISSEL is one of the four national winners of the CNRS 2020 Innovation Medal.

    Read more
  • A new source of infrared light thanks to fibre optic cascades

    Scientists from  FEMTO-ST Institute and McGill University (Montreal, Canada) have designed and developed in collaboration with three French companies a light source covering the entire mid-infrared wavelength range: from 2 to 10 µm.

    Read more
  • Topological crystals to guide waves on the water surface

    Topological crystals have the property of being conductive on their surface, but insulating in their volume which allows very efficient wave guidance by engineering the structure of these materials, generally arranged in a hexagonal symmetry, inspired by the graphene.

    Read more
  • An innovative solution to detect pollutants in the subsoil

    Researchers from FEMTO-STinstitute and the company TOTAL SA have succeeded in detecting organic pollutants with methods that did not require sampling and have been able to monitor the evolution of the pollution of the subsoil over periods ranging up to several years.

    Read more
  • FEMTO-ST is closed

    Within the framework of Coronavirus (COVID-19) epidemic and  following the measures announced by the President of the French Republic,  all the premises of our laboratory in Besançon, Belfort and Montbéliard cities are closed to the public from this Tuesday March 17.

    Read more
  • I-PhD Innovation Competition: 2 winners from FEMTO-ST

    Maya Geagea (ANIO-PAC project: micro fuel cells), and Gaël Matten (VIBISCUS project: noise reduction system), special jury prize, are winners of the 2019 innovation awards.

    Read more
  • Sarah Benchabane winner of an ERC Consolidator grant 2019

    CNRS Research Fellow at the FEMTO-ST Institute, Sarah is awarded with a prestigious €2M European Research Council (ERC) grant for her  project : Nanophonics for Quantum Information Processing.

    Read more

Pages