AsianScientist (Dec. 11, 2015) – Researchers at the RIKEN Center for Emergent Matter Science and Kyoto University’s Department of Polymer Chemistry have developed a polymer can minimize energy loss as effectively as silicon-based solar cells when converting photon energy from sunlight to electricity. The development, published in Nature Communications could overcome one of the largest barriers facing the technology.
Previously polymer-based solar cells have failed to match the power harvest of their more expensive silicon-based counterparts, because they lose more energy when converting photon energy from sunlight into electric power.
Sun photons strike electrons in solar cells and move them into a position where they can create an electric current.
“In polymer-based plastic solar cells, larger photon energy loss causes lower voltage. This has been one of the largest limiting factors for efficiency,” explains Kyoto University’s Associate Professor Hideo Ohkita, one of the study authors. “The new polymer has the potential to lead to a breakthrough on this issue.”
The group began working with the new polymer, where oxygen rather than sulfur atoms are located at key positions, and found that the new material was able to overcome some of the key obstacles to extracting and utilizing greater energy from sunlight.
“Since this new polymer greatly reduces photon energy loss, it has allowed us to achieve a superb power conversion efficiency of nearly nine percent with a very high open-circuit voltage in plastic solar cells,” explains Dr. Itaru Osaka, a senior research scientist at RIKEN.
An efficiency of 15 percent is usually seen as a breakthrough level that will allow polymer-based cells to be commercialized.
“By achieving both a high short-circuit current and a high open-circuit voltage,” Osaka continues, “achieving a power conversion efficiency of 15 percent in single-junction cells is a realistic goal. This would have huge implications for the solar energy sector.”
The article can be found at: Kawashima et al. (2015) High-efficiency Polymer Solar Cells with Small Photon Energy Loss.
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Source: Kyoto University.
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