C. Signorini

Fraunhofer Institute for Solar Energy Systems ISE, Freiburg, Baden-Württemberg, Germany

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Publications (15)0 Total impact

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    ABSTRACT: Currently ESA is considering a variety of missions which extend from extreme near-sun environment at Mercury out to Jupiter and beyond. These missions impose dramatically different environments (illumination intensity, operating temperature, particle radiation). This paper will discuss the challenges for solar array technology.
    Conference Record of the IEEE Photovoltaic Specialists Conference 01/2009;
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    ABSTRACT: A program for the development and qualification of advanced triple-junction space solar cells in Europe was initiated and supported by the European Space Agency ESA (contracts No. 18767/04/NL/FM "development of next generation GaAs-based multijunction solar cells" and No. 18118/04/NL/US "space qualification of European triple-junction solar cell RWE-3G") and the national German Zentrum fuer Luft- und Raumfahrt e.V. DLR (contract No. 50JR0442 "triple, quadruple and sextuple solar cells for space applications"). RWE Space Solar Power (D) is leading a research and development consortium including Fraunhofer-SE (D), Umicore (B), Galileo Avionica (I) and Astrium (D). The paper presents results of the work of these programs, in which triple junction solar cells with AM0-efficiencies of up to 30% are developed
    Photovoltaic Energy Conversion, Conference Record of the 2006 IEEE 4th World Conference on; 06/2006
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    ABSTRACT: The Fraunhofer ISE has developed a characterization tool called spectrometric characterization. In this paper we discuss that this tool is extremely powerful to characterize triple-junction (3J) EOL cells. The current-mismatch of the subcells can be determined and the performance for current-matched subcells can be predicted. Additionally, lattice-matched AlGaInP/GaInP/AlGaInAs/GaInAs/Ge quintuple-junction (5J) cells are being developed at Fraunhofer ISE as a possible next-generation of space solar cells. This material combination aims at the same BOL efficiency as state-of-the-art 3J cells but higher EOL efficiency. Based on spectral response measurements it will be demonstrated that the 5J cells do in fact show a higher radiation hardness compared to the 3J cell.
    Photovoltaic Specialists Conference, 2005. Conference Record of the Thirty-first IEEE; 02/2005
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    ABSTRACT: A programme for the development of advanced triple-junction space solar cells in Europe was initiated and supported by ESA and DLR. RWE Space Solar Power (D) has been leading a research and development consortium including UMICORE (B), CESI (I) with ENE (B), University of Paris (F), FhG-ISE (D) and Astrium (D). This paper presents results of the phase 2 work of this programme, in which triple junction solar cells with AMO-efficiencies of 27% have been realized. Additionally, the pre-development of the next generation of space solar cells with efficiencies above 30% is described.
    Photovoltaic Energy Conversion, 2003. Proceedings of 3rd World Conference on; 06/2003
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    ABSTRACT: The fluence dependences of the short circuit and the open circuit voltage, induced by an irradiation, depend on a single parameter k/spl sigma/, product of the introduction rates of the defects responsible for non radiative recombination times their trapping cross section. This parameter, characteristic of a given material, can be determined experimentally, hence allowing the computation of the degradation for any type of cell or multijunction cell. The validity of this procedure is demonstrated and illustrated in the case of the degradation of the short circuit current of 2J GaInP/GaAs/Ge cells.
    Photovoltaic Energy Conversion, 2003. Proceedings of 3rd World Conference on; 06/2003
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    ABSTRACT: Purpose of this work was the selection of materials and manufacturing processes able to withstand the high temperature conditions typical of interplanetary space missions towards the Sun (e.g. Mercury). There are only few experiences reported on this subject by the scientific community. The limited time (18 months) and funding available for this study imposes a developing approach using as much as possible existing technologies. This goal is achieved by means of an optimisation work performed on the already available space solar cells and photovoltaic assembly (PVA). The studies were developed in two different paths: experiments have been carded out through tests at CIC and coupon level; analyses based on a mathematical modelling of PVA concepts to confirm the experimental data. The above led to a "high temperature and insolation" PVA baseline technology selection that is now under testing. This campaign includes tests at CIC level (single and triple-junction GaAs calls) and at coupon level (Carbon and Aluminium substrate skins) and it will be completed within the end of year 2002.
    Photovoltaic Specialists Conference, 2002. Conference Record of the Twenty-Ninth IEEE; 06/2002
  • 05/2002;
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    04/2002; 502:445.
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    ABSTRACT: Si and GaAs solar cells have been irradiated with 1 MeV electrons at low temperatures, i.e. in conditions of deep space missions. The current-voltage characteristics have been recorded under 0.11 AM0 illumination produced by a filtered Xe lamp at the temperature of the irradiation. The variations of the open-circuit voltage and short-circuit current have been monitored versus fluence up to 10<sup>16 </sup> electrons cm<sup>-2</sup>, at temperatures ranging from 80 to 300 K. The maximum power degradation is found to be practically temperature independent in GaAs cells while it apparently reproduces the annealing stages of the introduced defects in Si cells. The variations of the short-circuit current with fluence and temperature can be understood in terms of the defect introduction rates in both Si and GaAs cases. These results indicate that, although the defect introduction rate can be larger in GaAs than in Si, the created defects appear more efficient to recombine minority carriers in Si than in GaAs
    Photovoltaic Specialists Conference, 1996., Conference Record of the Twenty Fifth IEEE; 06/1996
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    ABSTRACT: The deep space and planetary exploration project have been acquiring more and more importance and some of them are now well established both in ESA and NASA programs. This paper presents the possibility to utilize both silicon and gallium arsenide solar cells as spacecraft primary power source for missions far from the Sun, in order to overcome the drawbacks related to the utilisation of radioisotope thermoelectric generators - such as cost, safety and social acceptance. The development of solar cells for low illumination intensity and low temperature (LILT) applications is carried out in Europe by ASE (Germany) and CISE (Italy) in the frame of an ESA programme, aimed to provide the photovoltaic generators for ROSETTA: the cometary material investigation mission scheduled for launch in 2003. The LILT cells development and testing objectives are therefore focused on the following requirements: insolation intensity as low as 0.03 Solar Constant, low temperature down to -150 C and solar flare proton environment. At this stage of development, after the completion of the technology verification tests, it has been demonstrated that suitable technologies are available for the qualification of both silicon and gallium arsenide cells and both candidates have shown conversion efficiencies over 25% at an illumination of 0.03 SC and a temperature of -150 C. In particular, when measured at those LILT conditions, the newly developed 'Hl-ETA/NR-LILT' silicon solar cells have reached a conversion efficiency of 26.3%, that is the highest value ever measured on a single junction solar cell. A large quantity of both 'Hl-ETA/NR-LILT' silicon and 'GaAs/Ge-LILT' solar cells are presently under fabrication and they will be submitted to a qualification test plan, including radiation exposure, in order to verify their applicability with respect to the mission requirements. The availability of two valid options will minimize the risk for the very ambitious scientific project. The paper describes how the technical achievements have been possible with Si and GaAs LILT solar cells (including a comparison between measured and modelled l-V characteristics) and it presents the technology verification tests results.
    11/1995;
  • 09/1995;
  • 08/1995; 369:471.
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    ABSTRACT: This paper describes the possibility of utilising both silicon and gallium arsenide photovoltaic devices to electrically power either spacecraft for interplanetary missions far from the Sun such as the ESA ROSETTA deep space mission, or surface stations for interplanetary exploration such as foreseen in the Mars landing. The investigation particularly deals with the effects induced on solar cell performance by typical deep space environmental conditions such as low temperature and low solar intensities. Efficiencies of 25% at -100 C, 0.11 SC, of 27% at -150 C, 0.11 SC and still 26% at -150 C, 0.03 SC have been achieved for best HI-ETA/NR-LILT silicon solar cells with an area of 3.78 cm×6.19 cm and efficiencies of 24.1% at 0.11 SC, -130 C and 23.8% at 0.03 SC, -150 C for GaAs solar cells with an area of 2 cm×4 cm
    Photovoltaic Energy Conversion, 1994., Conference Record of the Twenty Fourth. IEEE Photovoltaic Specialists Conference - 1994, 1994 IEEE First World Conference on; 01/1995
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    ABSTRACT: Thin GaAs/Ge MOCVD solar cells have been developed in order to overcome the high cost and fragility of the more conventional GaAs/GaAs cells. Test results are presented for 120 and 200 μm thick, 2×2 and 2×4 cm<sup>2</sup> solar cells with an efficiency up to 19% AMO 25 C. The GaAs/Ge cells have been subjected to a complete testing procedure including electron (1 MeV) and proton (10 MeV) irradiation
    Photovoltaic Specialists Conference, 1991., Conference Record of the Twenty Second IEEE; 11/1991
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    ABSTRACT: This paper reviews the activities performed by CISE and Fiar in the last 6 years under the aegis of the Italian Space Agency (ASI), in establishing a reliable and qualified technology for GaAs space solar cells and modules. The aim of this industrial initiative is to produce advanced space solar cells for the future National satellites and to create a European capability, nowadays lacking in this field, in order to counter-balance similar enterprises already performed in the U.S.A., Japan and the U.S.S.R. This paper gives also detals concerning some recent technological achievements: 4 × 4 cm2, 18.4% AMO LPE solar cells, 2 × 2 and 2 × 4 cm2 MOVPE solar cells 21% AMO efficient assembling of GaAs flight panels for in-orbit demonstration programmes.
    Acta Astronautica. 01/1990;