Programm Photovoltaik Ausgabe 2009 ... - Bundesamt für Energie BFE

4. The UV-A tests with PMMA films containing the dye Red305 show the best stability after 100
hours in intense UV light, even when the PMMA matrix contains no additives to stabilize against UV
light. With some dyes such as CRS040, the additives gave an improved stability, but still not as good
as the Red305 durability.
From these findings, it seems that the Red305 dye dissolved in a carefully polymerized PMMA matrix
based on purified (distilled) MMA monomer gives the most promising stability results, with an apparent
degradation in absorption and spectral response of less than 10 % over a test period equivalent in
outdoors light exposure of 2 years.
5. Preliminary light soaking test done on quantum dot containing FPC's indicate that the quantum
dot luminescent "dye" is fairly stable, although these test only lasted 275 hours at a 950 W/m 2 light
intensity corersponding to an equivalent of ¼ year outside.
National and international collaboration
In the framework of the sub-project « Molecular Based Concepts », where ECN (Petten, NL) is the
sub-project leader, collaboration is essentially with Imperial College of Science, Medicine and
Technology (London, UK) regarding the special Si-solar cell supply, the Fraunhofer-Institut fuer
Angewandte Polymerforschung (Golm, DE) provides the PMMA-polymer based flat plate concentrator
sheets in sizes up to 10x10 cm (ca 3 to 5 mm thick), the University of Utrecht (Utrecht, NL) provides
the quantum dots & new dyes to the partners and RWE-SSP (Heidelberg, DE) provided the multijunction
solar cells to be built on the edges of the flat-plate concentrators.
National collaboration: as an alternative to the cut-out Si-cells, we are investigating the use of Dye Solar
Cells such as the ones developed by Prof M. Graetzel at the EPFL (Lausanne) and Solaronix. Dye
Solar Cells have the advantage of delivering a higher voltage than the Si-cells and they can be tailored
to the emission spectrum of the fluorescent dye employed in the Flat Plate Concentrator.
Evaluation 2008 and Outlook 2009
During that last project year, the stability corresponding to over 2 years outside equivalent exposure of
the Flat Plate Concentrator concept, employing the commercially available Red 305 dye and highly
purified PMMA matrix, was shown. For indoor application this stability behavior of the FPC system is
well sufficient to be used commercially in product application, opening the promise for a new, compact
and aesthetically pleasant solar power source.
During the final meeting in Madrid, the idea of continuing the FPC development and the two photon
concept investigation was raised by the partners, and the idea is to bid for upcoming projects, either
EC or nationally funded.
In this view, the project HET2PP, dealing with doped chalcogenides as 2-photon absorbing materials
was submitted by Dr. Jesús Alonso at ISOPHOTON, Madrid, Spain.
An other project in the Nanomaterials for Energy call might be submitted in 2009, together with Ms. Dr.
Sarah McCormack of the FULLSPECTRUM partner Dublin Institute of Technology, Ireland.
References
[1] A. Luque, A. Marti, A. Bett, V.M. Andreev, C. Jaussaud, J.A.M. van Roosmalen, J. Alonso, A. Räuber, G. Strobl, W. Stolz,
C. Algora, B. Bitnar, A. Gombert, C. Stanley, P. Wahnon, J.C. Conesa, W.G.J.H.M. van Sark, A. Meijerink, G.P.M. van
Klink, K. Barnham, R. Danz, T. Meyer, I. Luque-Heredia, R. Kenny, C. Christofides, G. Sala, P Benitez "FULLSPEC-
TRUM: a new PV wave making more efficient use of the solar spectrum" Solar Energy Materials & Solar Cells 87
(2005) 467-479.
[2] Slooff, A. R. Burgers, N. J. Bakker, T. Budel, A. Büchtemann, R. Danz, T. Meyer, A. Meyer, and T. H. Wadman�"The
luminescent concentrator: stability issues"�Proc. of 22nd European Photovoltaic Solar Energy Conference
(22ndEUPVSEC) Milan, 2007.
[3] S. H. Wadman, J. M. Kroon, K. Bakker, M. Lutz, A. L. Spek, G. P. M. van Klink, and G. van Koten�"Cyclometalated ruthenium
complexes for sensitizing nanocrystalline TiO2 solar cells"�Chemical Communications, vol. 19, pp. 1907-
1909, 2007.
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