New Solar Cell Discoveryby Staff
Laboratory News, February 16, 2017
An interdisciplinary team of scientists have created a blueprint for a new type of solar cell.
This technology relies on a solid-state cell made from the mineral perovskite. The researchers are taking advantage of a specific property in perovskite -- polaron excitations -- that combines both electron excitation and crystal lattice vibration.
Dirk Raiser, from the Max Planck Institute for Biophysical Chemistry, said: "In conventional solar cells, the interaction between the electrons and the lattice vibrations can lead to unwanted losses, causing substantial problems, whereas the polaron excitations in the perovskite solar cell can be created with a fractal structure at certain operating temperatures and last long enough for a pronounced photovoltaic effect to occur."
Traditional solar cells work when light energy knocks electrons loose from atoms in the semiconducting material, which then flow around a circuit, producing electricity. The perovskite cell method differs as it converts infrared radiation into electrical energy.
However, this experiment so far has been successful in a sub-zero controlled environment. Professor Simone Techert, also from the Max Planck Institute said: "Measurements so far were made in a carefully characterised reference material, in order to demonstrate the principle of the effect. For this purpose, the low transition temperature was accepted."
The perovskite solar cells had to be cooled to -35°C in order for this method to be successful. Researchers are investigating ways of altering and optimising the crystals in order for it to operate efficiently at higher temperatures. If successful, future solar cells or photochemical energy sources could be made using perovskite oxide compounds -- of which a plentiful supply exists.
Christian Joss, research director at the University of Göttingen, said: "Developing high efficiency and simply constructed solid-state solar cells is still a scientific challenge which many teams around the world are working on, in order to ensure the future of our energy supply. In addition to optimising the material and the design of existing solar cells, this also involves exploring new, fundamental mechanisms of light-induced charge transport and conversion into electrical energy. This should allow us to develop solar cells based on new operating principles. "
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