Progress in Photovoltaics: Research and Applications

Cover image for Vol. 19 Issue 7

Special Issue: 25th EU PVSEC WCPEC-5, Valencia, Spain, 2010

November 2011

Volume 19, Issue 7

Pages 757–910

  1. Special Issue Papers

    1. Top of page
    2. Special Issue Papers
    3. Literature Survey
    1. Regional PV power prediction for improved grid integration (pages 757–771)

      Elke Lorenz, Thomas Scheidsteger, Johannes Hurka, Detlev Heinemann and Christian Kurz

      Version of Record online: 8 SEP 2010 | DOI: 10.1002/pip.1033

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      An efficient grid integration of fluctuating PV power will highly benefit from PV power predictions. The regional PV power prediction system of University of Oldenburg and Meteocontrol GmbH providing forecasts up to 2 days ahead with hourly resolution is presented and evaluated for the control areas of two German transmission system operators. rmse values are in the range of 4–5% with respect to the nominal power for intra-day and day-ahead forecast horizons.

    2. Linking nanotechnology to gigawatts: Creating building blocks for smart PV modules (pages 772–780)

      J. Poortmans, K. Baert, J. Govaerts, R. Mertens, F. Catthoor, M. Germain, J. Das and J. Driesen

      Version of Record online: 7 OCT 2010 | DOI: 10.1002/pip.1034

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      In this paper we describe the philosophy behind the concept of the “Smart PV-module” and 2 potential enabling technologies to realize this concept. The first is related to the embedding technology for cells and components in the a module concept specifically aimed at thin crystalline Si solar cells whereas the second concerns the development of a low-cost technology for reliable high-power components based on GaN-on-Si, enabling a potential size reduction in DC-DC or DC-AC convertors.

    3. High efficient n-type back-junction back-contact silicon solar cells with screen-printed Al-alloyed emitter and effective emitter passivation study (pages 781–786)

      Chun Gong, Sukhvinder Singh, Jo Robbelein, Niels Posthuma, Emmanuel Van Kerschaver, Jef Poortmans and Robert Mertens

      Version of Record online: 3 SEP 2010 | DOI: 10.1002/pip.1035

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      We demonstrate the use of industrial-orientated screen-printed aluminum-alloyed p+ emitter for high-efficiency n-type back-junction back-contact silicon solar cells. Different cell designs with various pitch sizes and emitter fractions have been studied. With an improved front surface field, short-circuit current densities up to 40mA/cm2 can be obtained. By combining the best cell design and the improved FSF, a high conversion efficiency of 19.1% with Czochralski n-type material has been achieved. Moreover, better quality emitter and emitter passivation has been developed.

    4. Transport properties of p-type compensated silicon at room temperature (pages 787–793)

      F.E. Rougieux, D. Macdonald and A. Cuevas

      Version of Record online: 11 NOV 2010 | DOI: 10.1002/pip.1036

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      This paper summarizes recent findings regarding the carrier transport properties of compensated silicon. The capacity of common mobility models to describe compensated silicon is reviewed and compared to experimental data. The related problem of conversion between resistivity and dopant density in compensated silicon is discussed.

    5. Energy prediction of Amonix CPV solar power plants (pages 794–796)

      Geoffrey S. Kinsey, Kenneth Stone, Joseph Brown and Vahan Garboushian

      Version of Record online: 6 SEP 2010 | DOI: 10.1002/pip.1037

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      Amonix CPV Solar Power Plants currently demonstrate AC efficiency of over 25% in the field. A model has been developed that predicts system performance based on the spectral response of the III–V multijunction cell corrected for environmental and atmospheric conditions. With the cleaning schedule as the only adjustable variable, energy production has been within 2% of prediction after 9 months of operation. The model is used to improve performance, which is expected to increase by 10% in 2010.

    6. Band gap-voltage offset and energy production in next-generation multijunction solar cells (pages 797–812)

      R. R. King, D. Bhusari, A. Boca, D. Larrabee, X.-Q. Liu, W. Hong, C. M. Fetzer, D. C. Law and N. H. Karam

      Version of Record online: 18 NOV 2010 | DOI: 10.1002/pip.1044

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      Semiconductor device physics equations are formulated in terms of the band gap-voltage offset, Woc(Eg/q)−Voc, to give a clearer physical understanding and more general analysis of multijunction cells. Woc is shown to be largely independent of band gap Eg for a wide range of semiconductors, both experimentally and theoretically. Energy production of modeled 4-, 5-, and 6-junction solar cells is significantly greater than for conventional 3-junction cells. Light I-V measurements are presented for a record 41.6%-efficient GaInP/GaInAs/Ge 3-junction solar cell.

    7. Silicon quantum dot based solar cells: addressing the issues of doping, voltage and current transport (pages 813–824)

      Gavin Conibeer, Martin A. Green, Dirk König, Ivan Perez-Wurfl, Shujuan Huang, Xiaojing Hao, Dawei Di, Lei Shi, Santosh Shrestha, Binesh Puthen-Veetil, Yong So, Bo Zhang and Zhenyu Wan

      Version of Record online: 10 NOV 2010 | DOI: 10.1002/pip.1045

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      Quantum confinement in Silicon quantum dots can be used to engineer optimal effective band gaps for tandem cells which can be grown using thin film vapour phase processes such as sputtering or PECVD. However, very large resistances due to low tunnelling probabilities between quantum dots and an incomplete understanding of doping in these materials need to be addressed to improve device performance. Progress on reducing series resistance using nitride interlayers and a new model for ‘modified modulation’ doping are presented.

    8. First flight demonstration of film-laminated InGaP/GaAs and CIGS thin-film solar cells by JAXA's small satellite in LEO (pages 825–833)

      Chiharu Morioka, Kazunori Shimazaki, Shirou Kawakita, Mitsuru Imaizumi, Hiroshi Yamaguchi, Tatsuya Takamoto, Shin-ichiro Sato, Takeshi Ohshima, Yosuke Nakamura, Keiichi Hirako and Masato Takahashi

      Version of Record online: 10 NOV 2010 | DOI: 10.1002/pip.1046

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      The world's first experimental flight of the film-laminated InGaP/GaAs dual-junction thin-film solar cell was performed by JAXA's Small Demonstration Satellite-1 (SDS-1). It was verified that the degradation tendency of the cell performance corresponds to the predicted result calculated using the results of the ground test. Validity of the ground-test and prediction methodology adopted in this study was confirmed.

    9. Steps towards integration of PV-electricity into the GRID (pages 834–843)

      F. P. Baumgartner, T. Achtnich, J. Remund, S. Gnos and S. Nowak

      Version of Record online: 19 OCT 2010 | DOI: 10.1002/pip.1047

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      If PV power is further increased to an amount of 10% of the overall electricity generation in the Swiss Utility grid, about 8% of the PV electricity could find no demand, starting with surplus of PV production at noon at sunny weekends in summertime. Different scenarios are analysed to find out the PV losses for the today's Swiss load profile at constant base load, without constant base load and with additional storage available in Switzerland as pumped hydro capacities.

    10. Epitaxy-free monocrystalline silicon thin film: first steps beyond proof-of-concept solar cells (pages 844–850)

      V. Depauw, Y. Qiu, K. Van Nieuwenhuysen, I. Gordon and J. Poortmans

      Version of Record online: 10 NOV 2010 | DOI: 10.1002/pip.1048

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      The “Epifree” process involves the lift-off of a high-quality monocrystalline film formed by reorganization upon annealing of cylindrical macropore arrays in silicon, and can thus provide high-quality silicon films without resorting to epitaxy. Proof-of-concept cells have previously been achieved and this paper presents the latest progress, with a first development of thicker films up to 2.4µm and the inclusion of a-Si rear-side passivation. The efficiency of 1-µm-thin cells could be improved from 2.6 to 4.1% but the Voc stayed limited for a-Si passivation was found unsuitable for the current cell structure.

    11. Strategies to improve cyanine dye multi layer organic solar cells (pages 851–857)

      Roland Hany, Bin Fan, Fernando Araujo de Castro, Jakob Heier, William Kylberg and Frank Nüesch

      Version of Record online: 18 NOV 2010 | DOI: 10.1002/pip.1049

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      We report that cyanine dye/C60 bilayer solar cells with efficiencies of 2–3% can be fabricated by chemical doping or by energy level matching at the anode/cyanine interface using dipole layers or doped polyaniline. Aggregates and ionic space charge that builds up due to mobile anions are property characteristics of cyanines. Their proper use can open opportunities to improve the performance of cyanine solar cells and to realize new functionalities unique to organic opto-electronic devices.

    12. Control of preferential orientation of microcrystalline silicon and its impact on solar cell performance (pages 858–864)

      Kimihiko Saito and Michio Kondo

      Version of Record online: 10 NOV 2010 | DOI: 10.1002/pip.1053

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      The significance of preferential orientation in microcrystalline silicon for its post-oxidation properties and solar cell performance has been investigated in the high crystalline volume fraction range. The microcrystalline silicon films with strong <110>-preferential-orientation showed low degrees of post-oxidation and good solar cell performance. The origin of these preferential orientation impacts on post-oxidation and on solar cell performance is discussed in terms of amorphous silicon passivation on the grain boundaries.

    13. Recent results for single-junction and tandem quantum well solar cells (pages 865–877)

      J. G. J. Adams, B. C. Browne, I. M. Ballard, J. P. Connolly, N. L. A. Chan, A. Ioannides, W. Elder, P. N. Stavrinou, K. W. J. Barnham and N. J. Ekins-Daukes

      Version of Record online: 19 JAN 2011 | DOI: 10.1002/pip.1069

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      Strain-balanced quantum well solar cells are seen to have a fundamentally higher detailed balance limiting efficiency than bulk cells, as compressive strain in the quantum wells leads to a reduction in the dominant radiative recombination current. We also investigate the effect of quantum wells on the performance of tandem cells through efficiency calculations and report the characterization of such a device under concentration.

    14. A comparative study on life cycle analysis of 20 different PV modules installed at the Hokuto mega-solar plant (pages 878–886)

      Masakazu Ito, Mitsuru Kudo, Masashi Nagura and Kosuke Kurokawa

      Version of Record online: 5 JAN 2011 | DOI: 10.1002/pip.1070

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      The purpose of this study was to identify a suitable type of mega-solar system from an environmental viewpoint. The authors evaluated six types of 20 different PV modules by life cycle analysis (LCA) with actual equipment data and output. The results showed an energy requirement ranging from 19 to 48GJ/kW and an energy payback time of between 1.4 and 3.8 years. CO2 emissions were from 1.3 to 2.7 t-CO2/kW, and CO2 emission rates ranged from 31 to 67 g-CO2/kWh.

    15. Development of industrial high-efficiency back-contact czochralski-silicon solar cells (pages 887–893)

      James M. Gee, Prabhat Kumar, James Howarth, Todd Schroeder, Jeff Franklin, Jason Dominguez and David Tanner

      Version of Record online: 5 JAN 2011 | DOI: 10.1002/pip.1075

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      A 19%-efficient back-contact silicon solar cell using emitter wrap through (EWT) structure and only industrial processing is demonstrated..

    16. New world record efficiency for Cu(In,Ga)Se2 thin-film solar cells beyond 20% (pages 894–897)

      Philip Jackson, Dimitrios Hariskos, Erwin Lotter, Stefan Paetel, Roland Wuerz, Richard Menner, Wiltraud Wischmann and Michael Powalla

      Version of Record online: 5 JAN 2011 | DOI: 10.1002/pip.1078

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      In this contribution, we present a new certified world record efficiency of 20.1 and 20.3% for Cu(In,Ga)Se2 thin-film solar cells. We present the characteristics of solar cells on such a performance level and demonstrate a high degree of reproducibility as well.

    17. Characterization of high-efficiency c-Si CPV cells (pages 898–907)

      Mauro Pravettoni, Roberto Galleano, Raffaele Fucci, Robert P. Kenny, Antonio Romano, Michele Pellegrino, Tuomas Aitasalo, Giovanni Flaminio, Carlo Privato, Willem Zaaiman and Ewan D. Dunlop

      Version of Record online: 28 MAR 2011 | DOI: 10.1002/pip.1101

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      This paper focuses on the following two essential components of device calibration. First, the preparation of traceable calibrated reference cells for checking device linearity at different concentration ratios. Second, it is also essential to implement common procedures and intercomparison of results at different test laboratories. Procedures and experimental setups for concentrating c-Si cell characterization at ESTI and at the UTTP FOTO Laboratory of ENEA are described and results of an intercomparison are presented and discussed.

  2. Literature Survey

    1. Top of page
    2. Special Issue Papers
    3. Literature Survey
    1. Photovoltaics literature survey (No. 89) (pages 908–910)

      Santosh Shrestha

      Version of Record online: 20 OCT 2011 | DOI: 10.1002/pip.1212