News Port /Overview
Efficiency record September 2008
39.7% – New European
Record Efficiency for Solar Cells achieved by Fraunhofer ISE
At 39.7% efficiency for a multi-junction solar cell, researchers at the Fraunhofer Institute for Solar Energy Systems ISE in Freiburg have exceeded their own European record of 37.6% which they achieved just a short time ago. III-V semiconductor multi-junction solar cells are used in photovoltaic concentrator technology for solar power stations.
Efficiency record July 2008
37.6% – European Record Efficiency for Solar Cells from Fraunhofer ISE
With an efficiency of 37.6%, researchers at the Fraunhofer Institute for Solar Energy Systems convert sunlight into electrical energy, thus setting a new European record. The result was reached using so-called multi-junction solar cells made out of III-V semiconductors. Up to now such solar cells have been used primarily for space applications. The current developments of the Fraunhofer researchers facilitate the more cost-efficient use of these types of cells for terrestrial applications. For this purpose, sunlight is concentrated up to 2000 times and focused onto a multi-junction solar cell having an area of only a few square millimeters. The concentrator technology promises that the costs of generating electricity from sunlight can be considerably decreased already in the near future, especially in countries with a large fraction of direct solar radiation.
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Efficiency record February 2005
Recently,
lattice mismatched monolithic triple-junction cells were developed at
Fraunhofer ISE. They consist of Ga0.65In0.35P/Ga0.83In0.17As/Ge.
The first European triple-junction concentrator solar cell
achieved an efficiency of 35.2 % @600 suns (AM1.5d spectrum,
low AOD value), see figure 1. The cell was designed in such a way that
all three sub-cells generate the same current under the AM1.5d
spectrum, low AOD value. This was proven by integration of the external
quantum efficiency and the AM1.5d spectrum. It is noteworthy that in
the more commonly used Ga0.50In0.50P/Ga0.99In0.01As/Ge
lattice matched triple-cells Ge will always generate a higher current
than the upper lying cells. Consequently the lattice mismatched
approach has the higher efficiency potential.
Figure 1: Fill factor and efficiency versus
concentration ratio of a lattice mismatched triple-junction
concentrator solar cell.
An overview how this record has been achieved is given in:
F. Dimroth, C. Baur, A.W. Bett, M. Meusel, G. Strobl
“3-6
JUNCTION PHOTOVOLTAIC CELLS FOR SPACE AND TERRESTRIAL CONCENTRATOR
APPLICATIONS”
Awards
*********************************************************************************** On the
occasion of the 19th European Photovoltaic Solar
Energy Conference and Exhibition,
7-11 June 2004, Paris, France,
the presentation
L. Cuadra, A. Martí,
N. López, and A. Luque
“Phonon Bottleneck Effect and Photon Absorption in
Self-ordered
Quantum Dot Intermediate Band Solar Cells”
was selected by the official jury as the winner of the
Poster Award
in the thematic area of “Fundamentals,
Novel Devices and New Materials”.
This outstanding scientific poster was deemed to be an exemplary
contribution to
the 19th European Photovoltaic Solar Energy
Conference and Exhibition.
Please find here the Paper version of the Poster
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