Scientists at the Ohio State University have developed a new solar energy material that has two major advantages over current materials : it can use the all the energy that comes from the sunlight and makes it easier to capture the electrons it generates. The hybrid material is a result of combining electrically conductive plastic with molybdenum, titanium and other metals.
The study, lead by Malcom Chisholm, Chairman of the Department of Chemistry at Ohio State, is presented in the Oct 16 edition of the “Proceedings of the National Academy of Sciences (PNAS)”. “There are other such hybrids out there, but the advantage of our material is that we can cover the entire range of the solar spectrum,” said Chisholm.
This new material was developed exploring different molecular combinations at the Ohio Supercomputer Center, and then synthesised molecules of the new material in a solution, with help from the National Taiwan University’s Chemistry department. When they studied the material’s response to light, they uncovered that it had some great qualities.
Sunlight contains multiple light frequencies, each with it’s own energy, but conventional solar panels can convert only a certain range of those frequencies, thus not being very efficient. This new material can use all the energy the sunlight has at once.
But this new material can overcome another disadvantage the conventional solar panels have.
Solar cells produce electricity when light energizes the atoms and some of the electrons get knocked loose. In order to get electrical current, the electrons have to flow out the device before they get attracted back by the nucleus. In conventional solar panels, electrons stay loose for about 10 picoseconds ( 1 picosecond is 0.000 000 000 001 seconds and in 10 picoseconds light travels only 3 millimeters).Capturing these electrons is called charge separation and is tough to realise in such short time. But due to the fact that this new material emits electrons both in a single and a triple state, electrons stay free seven million times longer : 83 microseconds, and when the molecules were deposited in a thin film, electrons staid free for up to 200 picoseconds
This long-lived excited state should allow us to better manipulate charge separation,” Chisholm said.
The project was funded by the National Science Foundation and Ohio State’s Institute for Materials Research, and even tough this material is years away from commercial development, this new discovery proves that solar panels can become an important source of energy in the future.
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