Generate more electricity from solar cells and further research on so-called single-state fission. This is part of a joint research project being carried out by scientists at the University of Friedrich-Alexandria-Erlangen-Nuremberg (FAU), in collaboration with the Argonne-Northwest Solar Research Center (Anser) at Northwestern University in Evanston. Single-line fission can greatly improve the efficiency of solar cells--thanks to the latest research, it is a step closer to being possible.
The findings are published in the journal Science of Chemistry. Global energy consumption is growing rapidly, and this upward trend will continue over the next few years. Renewable energies such as solar, wind, hydro and biomass are becoming increasingly important in order to meet demand while protecting the environment.
However, only about 6% per cent of the total power generated in Germany in 2017 years comes from photovoltaic systems, and our existing silicon-based technology is rapidly reaching the limits of potential.
Silicon-based photovoltaic technology is rapidly reaching the limit of potential (images from the Internet)
Using solar cells to generate electricity Solar cells are extremely inefficient in turning solar energy into electricity. Their current efficiency is only 20% to 25%. New approaches have been called for to significantly improve the performance of solar cells and generate more electricity. The answer may be found in physicochemical processes, which will greatly improve the efficiency of solar cells. Scientists at the FAU and Anser centers have been exploring a promising approach, which is part of their joint research project in the Emerging Sector Program (EFI).
The researchers studied the so-called single-state fission (SF) mechanism, a photon that excites two electrons.
Better understanding of single-state fission The principle of single-line fission was discovered about 50 years ago, but its potential to significantly improve the efficiency of organic solar cells was recognized only a decade ago by American scientists. Since then, researchers around the world have been working to gain a deeper understanding of the underlying processes and complex mechanisms behind them. Professor Michael Wasielewski from the center of Anser, professor of Physical chemistry, chairman of the FAU-Dirk Guldi, Prof. Rik Tykwinski professor of Organic Chemistry (University of Alberta, Canada), professor of theoretical Solid state physics, Michael
Professor Tim Clark, Dr. Thoss (Albert-ludwigs-universität Freiburg) and the Computer Chemistry Center (CCC), is now trying to clarify some of the most important aspects of single-state fission (SF).
A detailed understanding of the process When photons from sunlight meet and are absorbed by molecules, an electron energy level in the molecule increases. By absorbing photons, organic molecules are thus transformed into high-energy states. The solar cell can then use the energy that is temporarily stored in the molecule to generate electricity. The best solution for conventional solar cells is for each photon to produce an electron as a carrier of electrical energy. However, if two of the selected compound is used, two electrons from the neighboring molecule can be converted to a higher energy state. In general, a photon produces two excited electrons, which can then be used to generate electricity. This process is known as single-line fission (SF), which in ideal conditions can greatly improve the performance of solar cells.
Chemists and physicists at the FAU and Anser centers have studied the underlying mechanism in more detail, thus providing a broader understanding of the SF process. Single-state fission (SF) is the process of converting a single-excited state into two triplet states.
Three important discoveries As a first step in the study, the scientists produced a molecular two polymer from two isoprene units. This hydrocarbon is considered to be a promising option for the use of single-line fission in solar cells.
They then exposed the liquid to light and used various spectral methods to study the optical physical processes within the molecule. This gives researchers a three-far-reaching understanding of the mechanism of single-strand fission in the molecule. First, they successfully proved that coupling to a higher charge transfer state is essential for efficient SF. Second, they validated their recent creation and publication of a single-state fission model (doi:10.1038/ncomms15171).
The third and last, they prove that the SF efficiency is obviously related to the coupling strength of two isoprene subunits. The researchers ' findings show the importance of carefully planning the design of SF materials. This is an important milestone in the use of SF-based photovoltaic systems for power generation.
