The study, conducted by an interdisciplinary team of international researchers, is part of the framework agreement between Eni and CNR as well as the Eni-MIT partnership that began in 2008. The results were published in Nature Materials.

Solar devices and sensors will become even more efficient, thanks to the combination of quantum physics and biochemistry. The study, conducted by an interdisciplinary team of international researchers, is part of the framework agreement between Eni and CNR as well as the Eni-MIT partnership that began in 2008. The results were published in Nature Materials.

 

San Donato Milanese, 17 December 2015 - Solar and sensor technologies will become more efficient, thanks to the combination of quantum physics and biochemistry. This is the result of the study "Enhanced energy transport in genetically engineered excitonic networks", published in October by the prestigious scientific journal Nature Materials. The study was conducted
by an interdisciplinary team of international researchers from the Departments of Physics and Astronomy as well as the European Laboratory for Non-linear Spectroscopy (LENS) at the University of Florence, the Department of Chemistry at the University of Perugia, the National Institute of Optics of the National Research Council (CNR-INO), the "Quantum Science and Technology in Arcetri "(QSTAR) research center, the Massachusetts Institute of Technology (MIT) and the Eni Donegani Research Center of Novara. The research is part of the framework agreement between Eni and CNR as well as the Eni-MIT partnership that began in 2008.

To achieve optimum transport efficiency in imitating natural systems, the research team used artificial photosynthetic antennas developed at MIT laboratories. These antenna systems were obtained by genetically modifying the protein structure of a harmless virus and anchoring two types of chromophores at precise points within the structure: donors (light absorbers) and acceptors (light emitting diodes). The genetic manipulation of the virus allows the distance between the support points of chromophores to be controlled, and consequently the strength of the interaction between them, which is in turn responsible for the transport efficiency in excitation energy.

Natural photosynthesis, which is responsible for life on Earth, takes place through a process in which light is captured by a protein-based '"receiving antenna", and then transmitted by a chain of pigments associated with it, called chromophores, to the "power station", the center of reaction, where it is converted into biologically usable energy.

While the overall photosynthetic process has efficiencies of less than 1%, the transport of energy in the form of electronic excitation has an efficiency of almost 100% even at room temperature, far superior to that of the best solar cells. In recent years, experimental results supported by theoretical models have shown that behind this extraordinary efficiency, there are effects that can only be explained only by the principles of quantum physics, for which the '"energy unit" (exciton) is simultaneously created on different chromophores along various parallel paths in order to find the optimum route to the center of the reaction. Under these conditions, instead of posing an obstacle as would normally be expected, the molecular movements active at room temperature make the processes faster instead.

"After a seminar held by MIT at our facility," explained the Eni Donegani Research Center, "we realized that these 'antenna systems' could have been used - with some modifications - to achieve high efficiency solar devices, by using the same process of capturing light in natural photosynthesis." Eni has therefore promoted a new project with MIT to study potential phenomena of quantum transport in these systems, which also sees the involvement of the INO CNR and LENS of the University of Florence.

"To analyze the energy transport in antenna systems," explains Paolo De Natale, INO CNR Director, "we performed an experiment in which they are stimulated by very fast laser pulses, which is first absorbed by the donor molecules and then re-emitted by the acceptor, thus measuring the transport efficiency. For genetically modified structures, we measured an exciton propagation that was twice as fast compared to the same antennas based on an unmodified virus, and consequently with propagation distances greater than 67%."

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