The Nanospec project
Motivation |
Silicon solar cells lose more than 20% of the energy incident from the sun because photons with an energy below the bandgap are transmitted straight through the device. Upconversion of these photons aims at increasing the efficiency of solar cells, by making also these photons useful. An upconverter generates one high-energy photon out of at least two low energy photons. These high energy photons can than be used by the solar cell. |
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Approach |
In the Nanospec project seven European partners joint their forces to develop an adavanced upconverting system that significantly enhances solar cell efficiencies. Key features were the upconverter material, the combination with second luminescent material to enlarge the used spectral region, photonic structures for photon management and efficient solar cells. |
The upconverter NaYF4:Er3+ illuminated with invisible infrared laser radiation shines bright in the visible. This is the effect of upconversion. |
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To achieve these goals, this project created significant progress in the science and technology of nanostructures and nanotechnology-based materials. The following detailed list of objectives were pursued:
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An upconverter system with all these features was realized in the Nanospec project. |
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Key results |
Overall the development of efficient upconverter materials and the realization of adapted silicon solar cells lead to increase of upconversion performance by more than an order of magnitude during the coarse of the Nanospec project. |