Only part of the solar radiation falling on the photovoltaic cells is used to produce energy. The rest of the energy is lost as heat. Scientists from the Warsaw University of Technology are working on a material that can increase the efficiency of PV cells.
The researchers are developing a material with a negative refractive index, which will not only reduce the heating of the cell, but will also increase the efficiency of energy generation, the Warsaw University of Technology reports on its website.
The scientists said: “According to the theoretical preliminary research, a properly designed hyperbolic metamaterial can act as an edge filter for a photovoltaic cell, reflecting infrared radiation that causes the cell heating up and, consequently, decreases its energy efficiency.”
The research team leader Dr. Bartosz Fetliński explained that scientists simulate electrical and optical parameters, and verify their assumptions experimentally.
He said: “We are creating a structure of a hyperbolic metamaterial composed of ultra-thin layers, with a thickness measured in nanometers. The structure will make it possible to obtain filters with a very sharp edge, offering very good filtration and allowing to achieve a rapid transition from transmission to absorption or reflection.”
The resulting hyperbolic metamaterials can be used in photovoltaic panels to reduce their heating.
Dr. Fetliński added: “The energies of infrared photons are lower than that of visible light photons and are not used to produce electricity at all, but they are absorbed by various elements of the photovoltaic module.
“There is no energy gain from this, but the module heats up. If we add such a metamaterial filter on a photovoltaic module, the permeability of photons in the useful range is good, and we can get rid of the rest that cause heating up.”
Experimental verification of metamaterial structures is carried out in collaboration with national research centres: the Łukasiewicz - the Institute of Microelectronics and Photonics and the Institute of Physics of the Polish Academy of Sciences. At the Faculty of Electronics and Information Technology of the Warsaw University of Technology, the research team will have the support of Professor Robert Mroczyński, who can produce some of the layers using magnetron sputtering, the Warsaw University of Technology reports.
Dr. Fetliński emphasised that so far hyperbolic metamaterials have not been used in similar applications.
The project 'Application of hyperbolic metamaterial for increasing the energy yield of photovoltaic modules' is financed by a research grant of the Priority Research Areas Research Centre Photonic Technologies of the Initiative of Excellence - Research University programme, implemented at the Warsaw University of Technology.
PAP - Science in Poland
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