Progress in Photovoltaics: Research and Applications

Cover image for Vol. 22 Issue 9

Early View (Online Version of Record published before inclusion in an issue)

Edited By: Martin A. Green, Ryne P. Raffaelle, Tim M. Bruton, Gavin Conibeer, Jean-Francois Guillemoles

Impact Factor: 9.696

ISI Journal Citation Reports © Ranking: 2013: 4/82 (Energy & Fuels); 9/136 (Physics Applied); 15/251 (Materials Science Multidisciplinary)

Online ISSN: 1099-159X


  1. 1 - 100
  2. 101 - 136
  1. Research Articles

    1. Regional forecasts of photovoltaic power generation according to different data availability scenarios: a study of four methods

      Joao Gari da Silva Fonseca Junior, Takashi Oozeki, Hideaki Ohtake, Takumi Takashima and Kazuhiko Ogimoto

      Article first published online: 20 AUG 2014 | DOI: 10.1002/pip.2528

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      Main findings:

      • 1
        Method 1, based on single-system information, yielded the lowest forecast errors in all regions.
      • 2
        Method 2, based on stratified sampling with weight correction for the rated power, presented a forecast error accuracy close to the that of method 1, being a good alternative to it.
      • 3
        The lowest annual forecast mean absolute errors, normalized by the average annual photovoltaic power generation found for Chubu and Kanto, were 0.156 and 0.202 kWh/kWhavg, respectively.
  2. Accelerated Publications

    1. You have free access to this content
      Role of oxygen during CdTe growth for CdTe photovoltaic devices

      Bas A. Korevaar, James R. Cournoyer, Oleg Sulima, Aharon Yakimov and James N. Johnson

      Article first published online: 13 AUG 2014 | DOI: 10.1002/pip.2547

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      Adding oxygen to the CdTe growth process results in increased carrier lifetimes. This has resulted in a 10–20 mV improvement in open-circuit voltages when growing the CdTe in pure oxygen, contributing to achieving 18.3% record cells in the end of 2012.

  3. Research Articles

    1. Low energy ion scattering: surface preparation and analysis of Cu(In,Ga)Se2 for photovoltaic applications

      Helena Téllez, John Druce, Allen Hall, Tatsumi Ishihara, John Kilner and Angus Rockett

      Article first published online: 13 AUG 2014 | DOI: 10.1002/pip.2535

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      Smooth Cu(In,Ga)Se2 epitaxial single crystals with metal and Se terminated surfaces were studied by low energy ion scattering. Surface preparation methods were compared. Atomic H was shown to selectively result in a surface devoid of Cu while atomic O and 500 eV ion sputtering leaves a surface with stoichiometry similar to the bulk material. Atomic O also leaves a surface oxide.

    2. Insights into corrosion in dye solar cells

      Kati Miettunen, Jarkko Etula, Tapio Saukkonen, Sami Jouttijärvi, Janne Halme, Jyrki Romu and Peter Lund

      Article first published online: 4 AUG 2014 | DOI: 10.1002/pip.2534

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      The required corrosion resistance in dye solar cells is about 1000× higher compared with usual case in corrosion science. Therefore, traditional methods to measure corrosion were found insufficient to prove a metal stable in working dye solar cells. A new method to investigate corrosion stability in dye solar cells is suggested on the basis of testing the cells in working conditions and extrapolating future performance on the basis of color changes.

  4. Accelerated Publications

    1. You have free access to this content
      20.7% efficient ion-implanted large area n-type front junction silicon solar cells with rear point contacts formed by laser opening and physical vapor deposition

      Yuguo Tao, Adam Payne, Vijaykumar D. Upadhyaya and Ajeet Rohatgi

      Article first published online: 31 JUL 2014 | DOI: 10.1002/pip.2545

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      Laser pulse energy was found to be critical in minimizing damage to the surface of the n+ back surface field layer and achieving good point contacts. An in situ Argon plasma treatment prior to depositing physical vapor deposition (PVD) Al, and a post-PVD anneal in an air ambient for less than 3 min, accomplished the desired Si/Al contact quality. In-depth optimization of these parameters and the rear contact pitch resulted in 20.7% efficient large area n-type front junction ion-implanted cells with screen-printed front contacts.

  5. Research Articles

    1. Time-resolved investigation of Cu(In,Ga)Se2 growth and Ga gradient formation during fast selenisation of metallic precursors

      Roland Mainz, Alfons Weber, Humberto Rodriguez-Alvarez, Sergiu Levcenko, Manuela Klaus, Paul Pistor, Reiner Klenk and Hans-Werner Schock

      Article first published online: 30 JUL 2014 | DOI: 10.1002/pip.2531

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      Cu(In,Ga)Se2 formation, Ga segregation and cation ordering during fast selenisation of Cu–In–Ga precursor films in elemental Se vapour are investigated by a combination of in situ and ex situ methods. Ga accumulation at the back occurs by outdiffusion of In and Cu out of the metallic layer. It was found that cation ordering determines the minimum time needed for the fabrication of high-quality chalcopyrite films. Solar cell efficiencies of around 14% were achieved with 6.5 min total annealing time.

    2. Broadband absorption enhancement in ultra-thin crystalline Si solar cells by incorporating metallic and dielectric nanostructures in the back reflector

      Samarth Jain, Valerie Depauw, Vladimir D. Miljkovic, Alexander Dmitriev, Christos Trompoukis, Ivan Gordon, Pol Van Dorpe and Ounsi El Daif

      Article first published online: 19 JUL 2014 | DOI: 10.1002/pip.2533

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      The back reflecting scheme of a c-Si ultrathin solar cell was optimized using both metallic and dielectric nanoparticles. During optimisation, a focus was made on light trapping in the red part of the spectrum. As a result, the absorption of a 1micron thick c-Si slab is enhanced by more than 60%.

    3. Reducing shadowing losses with femtosecond-laser-written deflective optical elements in the bulk of EVA encapsulation

      Ladislav Kuna, Gabriele C. Eder, Claude Leiner and Gerhard Peharz

      Article first published online: 19 JUL 2014 | DOI: 10.1002/pip.2530

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      A new approach on decreasing the optical shadowing of the solar cell grid fingers is presented. The approach relies on a local change of the optical properties in the bulk of the photovoltaic module encapsulation material ethylene vinyl acetate (EVA). In particular, scattering and diffractive optical elements are locally generated within the volume of cross-linked EVA encapsulation material by applying a femtosecond-laser-writing process.

  6. Applications

    1. Development of a high/low concentration photovoltaic module with dichroic spectrum splitting

      Andrea Antonini, Mariangela A. Butturi, Paolo Zurru, Matthew Norton and Antonio Parretta

      Article first published online: 14 JUL 2014 | DOI: 10.1002/pip.2532

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      The design and the development of a concentration photovoltaic module incorporating a spatial spectral splitting approach with dichroic mirrors are described in this paper, reporting some results of preliminary experimental tests.

      A critical analysis of materials, design and assembly procedures is presented, keeping in mind the fundamental constrains of cost and reliability of the final product. Finally, the possibilities for market exploitation of this technology in the current photovoltaic landscape are evaluated.

  7. Research Articles

    1. Liquid-selenium-enhanced grain growth of nanoparticle precursor layers for CuInSe2 solar cell absorbers

      Alexander R. Uhl, Peter Fuchs, Alexandra Rieger, Fabian Pianezzi, Carolin M. Sutter-Fella, Lukas Kranz, Debora Keller, Harald Hagendorfer, Yaroslav E. Romanyuk, Fabio LaMattina, Songhak Yoon, Lassi Karvonen, Theresa Magorian-Friedlmeier, Erik Ahlswede, Dirk VanGenechten, Fabrice Stassin and Ayodhya N. Tiwari

      Article first published online: 10 JUL 2014 | DOI: 10.1002/pip.2529

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      Large-grained CuInSe2 absorber layers are synthesized using a non-vacuum process based on nanoparticle ink precursors and selenization by rapid thermal processing, bypassing the need for explosive and/or toxic hydrazine solvent or H2/H2Se gasses. A liquid-selenium-assisted process enabled solar cell efficiencies of up to 8.73%, overcoming the inherently high layer porosity for previous nanoparticle processes.

    2. Luminescent solar concentrators employing new Eu(TTA)3phen-containing parylene films

      Michele Tonezzer, Gianluigi Maggioni, Antonio Campagnaro, Sara Carturan, Alberto Quaranta, Monica della Pirriera and David Gutierrez Tauste

      Article first published online: 3 JUL 2014 | DOI: 10.1002/pip.2524

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      New robust luminescent solar concentrators (LSCs) were produced by growing Eu(TTA)3phen-containing parylene thin films on poly(methyl methacrylate) slabs through a novel co-deposition process. The physical features and the occurring host–guest energy transfer process improve the optical properties and the solar capabilities of the LSC devices. These new LSCs produce a current density more than two times higher than conventional Eu(TTA)3phen ones and an efficiency decrease more than twenty times lower than common dye-based LSC at increasing illuminating area.

  8. Accelerated Publications

    1. You have full text access to this OnlineOpen article
      Employing Si solar cell technology to increase efficiency of ultra-thin Cu(In,Ga)Se2 solar cells

      Bart Vermang, Jörn Timo Wätjen, Viktor Fjällström, Fredrik Rostvall, Marika Edoff, Ratan Kotipalli, Frederic Henry and Denis Flandre

      Article first published online: 2 JUL 2014 | DOI: 10.1002/pip.2527

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      Reducing absorber layer thickness below 500 nm in regular Cu(In,Ga)Se2 solar cells decreases cell efficiency considerably: both short-circuit current and open-circuit voltage are reduced, respectively due to incomplete absorption and high Mo/Cu(In,Ga)Se2 rear interface recombination. In this work, an innovative rear cell design is developed to avoid both effects: a highly reflective rear surface passivation layer with nano-sized local point contacts is used to enhance rear internal reflection and decrease rear surface recombination velocity significantly.

  9. Research Articles

    1. Transparent conductive oxide-less back contact dye-sensitized solar cells using cobalt electrolyte

      Md. Zaman Molla, Norihiro Mizukoshi, Hiroaki Furukawa, Yuhei Ogomi, Shyam S. Pandey, Tingli Ma and Shuzi Hayase

      Article first published online: 25 JUN 2014 | DOI: 10.1002/pip.2526

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      Back contact transparent conductive oxide-less (TCO-less) dye-sensitized solar cells utilizing cobalt complex-based redox electrolyte having prospect of cost reduction due to reduced TCO content and enhanced photon harvesting in lower wavelength region due to less color of the electrolyte are being reported. Coating of thin layer of Ti metal (240 nm) on the stainless steel mesh as a charge recombination blocking layer led to drastic enhancement in the photoconversion efficiency from 0.66% (bare metal mesh) to 3.33% after the Ti protection. Owing to the bulkier size, sluggish ion diffusion and being more prone to charge recombination with conducting metal substrate for cobalt complex-based redox species, a strict control for the surface passivation was found to be crucial for further enhancement in the photoconversion efficiency.

    2. Laser-fired contact for n-type crystalline Si solar cells

      Jianbo He, Steven Hegedus, Ujjwal Das, Zhan Shu, Murray Bennett, Lei Zhang and Robert Birkmire

      Article first published online: 17 JUN 2014 | DOI: 10.1002/pip.2520

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      Ohmic contact for n-type crystalline silicon was obtained by laser firing metal stack containing Antimony (Sb). Specific contact resistance values of 2–7 mΩcm2 have been achieved. Surface recombination velocity of contact area is calculated to be ~20 000 cm/s, which is similar to values for laser-fired base contact for p-type crystalline silicon. Interdigitated back contact silicon heterojunction cells were fabricated with laser-fired base contact and efficiencies of 16.9% were achieved.

    3. Adhesive bonding for mechanically stacked solar cells

      Ian Mathews, Donagh O'Mahony, Kevin Thomas, Emanuele Pelucchi, Brian Corbett and Alan P. Morrison

      Article first published online: 13 JUN 2014 | DOI: 10.1002/pip.2517

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      Mechanically stacked solar cells formed using adhesive bonding are proposed as a route to high-efficiency devices as they enable the combination of a wide range of materials and bandgaps. The concept involves adhesive bonding of subcells using polymeric materials widely used in semiconductor processing. A dual-junction, GaAs-InGaAs, mechanically stacked solar cell is demonstrated using a benzocyclobutene adhesive layer with a measured PV conversion efficiency of 25.2% under 1-sun AM1.5G conditions.

    4. Employing microsecond pulses to form laser-fired contacts in photovoltaic devices

      Ashwin S. Raghavan, Todd A. Palmer, Katherine C. Kragh-Buetow, Anna C. Domask, Edward W. Reutzel, Suzanne E. Mohney and Tarasankar DebRoy

      Article first published online: 13 JUN 2014 | DOI: 10.1002/pip.2523

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      Microsecond pulse lengths are used to fabricate laser-fired contacts to avoid significant ablation of the aluminum metallization layer and to increase the interfacial contact surface area. In this work, the influence of changes in laser processing parameters on contact morphology, resistance, and composition when using microsecond pulses has been fully evaluated. Device simulations and experimental results indicate that these contacts exhibit a hemispherical or half-ellipsoidal shape that can be tailored to optimize total contact resistance without degrading the passivation layer.

    5. A new class of multi-bandgap high-efficiency photovoltaics enabled by broadband diffractive optics

      Peng Wang, Jose A. Dominguez-Caballero, Daniel J. Friedman and Rajesh Menon

      Article first published online: 9 JUN 2014 | DOI: 10.1002/pip.2516

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      We designed, fabricated, and applied a micro-optical element (polychromat) that spectrally separates and concentrates sunlight onto appropriate solar cells in order to enhance the overall photovoltaic efficiency. The polychromat operates with very high efficiency over the solar spectrum and can be manufactured inexpensively. Furthermore, our architecture offers enormous design freedom in the choice and sizes of the solar cells enabling entirely new applications of solar energy.

    6. Wet-milled anatase titanium oxide nanoparticles as a buffer layer for air-stable bulk heterojunction solar cells

      Jen-Hsien Huang, Mohammed Aziz Ibrahem and Chih-Wei Chu

      Article first published online: 6 JUN 2014 | DOI: 10.1002/pip.2522

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      A facile, inexpensive, scalable, and clean preparation of TiO2 nanoparticles solution via wet-milling method was proposed. During the grinding process, large clumps of the TiO2 underwent deaggregation to form a stable dispersed solution. The resultant suspension can form a uniform and smooth film through spin coating on various substrates. Corresponding TiO2 interlayers effectively block holes and collect electrons from [6,6]-phenyl C61-butyric acid methyl ester, promoted dramatically after ultraviolet activation, in addition to significant enhancement in the durability of organic solar cells.

    7. Impact of spatial separation of type-II GaSb quantum dots from the depletion region on the conversion efficiency limit of GaAs solar cells

      Ara Kechiantz, Andrei Afanasev and Jean-Louis Lazzari

      Article first published online: 6 JUN 2014 | DOI: 10.1002/pip.2521

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      We propose a novel structure with GaSb/GaAs type-II quantum dot absorber spatially separated from the depletion region by electron blocking barrier, but still within the diffusion length from this region. Calculation based on the detailed balance principal shows that type-II quantum dots do not reduce the open-circuit voltage but facilitate generation of the additional photocurrent with concentration of sunlight to such extant that in the ideal case the conversion efficiency meets the Luque-Marti limit.

  10. Applications

    1. You have free access to this content
      Modeling the maximum power output of a distributed PV fleet

      Georg Wirth, Elke Lorenz, Andreas Spring, Gerd Becker, Robert Pardatscher and Rolf Witzmann

      Article first published online: 5 JUN 2014 | DOI: 10.1002/pip.2513

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      In areas with a high photovoltaic (PV) penetration, the installed PV capacity is the decisive factor in network planning. This article discusses meteorological impacts on distribution networks in these areas. The maximum feed-in of a distributed PV fleet is found for clear sky situations with a limit of 85% of the installed standard test condition power. This limit could be confirmed by the analysis of measured PV power feed-in and its impact on the voltage levels in a distribution grid.

  11. Research Articles

    1. You have full text access to this OnlineOpen article
      Assessment of photovoltaic junction position using combined focused ion beam and electron beam-induced current analysis of close space sublimation deposited CdTe solar cells

      Jonathan Douglas Major, Leon Bowen, Robert Treharne and Ken Durose

      Article first published online: 1 JUN 2014 | DOI: 10.1002/pip.2507

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      Electron beam-induced current analysis of cadmium telluride (CdTe) solar cells shows the photovoltaic junction to be moved towards the CdTe/cadmium sulfide interface from the back surface via cadmium chloride annealing. Comparisons are made with external quantum efficiency (EQE) analysis, and the limitations of identifying junction position from EQE measurements are discussed.

    2. Improved lifetimes of organic solar cells with solution-processed molybdenum oxide anode-modifying layers

      Ashish Garg, Shailendra Kumar Gupta, Jacek J. Jasieniak, Th. Birendra Singh and Scott E. Watkins

      Article first published online: 29 MAY 2014 | DOI: 10.1002/pip.2512

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      In this manuscript, we show life time comparison between P3HT/PCBM organic solar cell devices using PEDOT/PSS or MoOx thin films as anode modifying layer, fabricated on indium tin oxide-coated glass substrates with normal device architecture using indium tin oxide as anode and aluminum as cathode. The devices with solution processed MoOx show a staggering 20 times improvement in the life times over those fabricating using conventional PEDOT/PSS layers.

    3. Below-bandgap absorption in InAs/GaAs self-assembled quantum dot solar cells

      Tian Li and Mario Dagenais

      Article first published online: 29 MAY 2014 | DOI: 10.1002/pip.2515

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      The insertion of self-assembled quantum dots in the crystal lattice leads to a perturbation of the band edge that can be described by an extended Urbach tail. Sources for below-bandgap one-photon absorption include tail absorption, quantum dots, and wetting layer absorption. The Urbach tail absorption accounts for 45% of the total below-bandgap absorption in the tested sample. Besides enhanced photo-generated current density, the tail absorption is also responsible for the degradation of the open-circuit voltage.

    4. Interconnection of busbar-free back contacted solar cells by laser welding

      Henning Schulte-Huxel, Susanne Blankemeyer, Agnes Merkle, Verena Steckenreiter, Sarah Kajari-Schröder and Rolf Brendel

      Article first published online: 29 MAY 2014 | DOI: 10.1002/pip.2514

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      We present a module integration process for aluminum metalized, busbar-free back-junction back-contact solar cells by means of laser welding. Our proof-of-concept module has a fill factor of 80.5% and conversion efficiency on designated area of 22.1% prior to lamination. By using this process for interconnection of 25 × 125-mm²-large cell strips, the fill factor of the module is increased by 3.5% absolute compared with the initial 125 × 125-mm²-large solar cell.

  12. Applications

    1. Solar irradiation and PV module temperature dispersion at a large-scale PV plant

      Miguel García, Luis Marroyo, Eduardo Lorenzo, Javier Marcos and Miguel Pérez

      Article first published online: 29 MAY 2014 | DOI: 10.1002/pip.2518

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      At large-size photovoltaic (PV) plants, the possible dispersion of the plant operating conditions (incident irradiance and cell temperature) may affect the representativeness of the values measured at one single point and, therefore, the results of the performance evaluation. In the available literature, no studies have been made on the long-term energy-related effects of geographic dispersion of solar irradiation. This paper analyses the geographical dispersion in the PV operating conditions observed at low temporal resolutions (day, month and year) at two PV plants

  13. Research Articles

    1. Recent progress of high efficiency Si thin-film solar cells in large area

      Dong Joo You, Sun Ho Kim, Hyun Lee, Jin-Won Chung, Sun-Tae Hwang, Youn Ho Heo, Sungeun Lee and Heon-Min Lee

      Article first published online: 29 MAY 2014 | DOI: 10.1002/pip.2510

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      We have developed a triple junction cell (a-Si:H/a-SiGe:H/µc-Si:H) technologies for the high efficiency. We have achieved a world record of 13.4% stabilized efficiency in small size cell and 10.5% stabilized efficiency in the large area module. We reviewed these technologies in this paper.

    2. Formation of charge-transfer complexes significantly improves the performance of polymer solar cells based on PBDTTT-C-T: PC71BM

      Guangsheng Fu, Shaopeng Yang, Jiangbo Shi, Zhiyong Zhang, Boya Liu, Xiaohui Zhao, Guang Li and Xiaowei Li

      Article first published online: 10 MAY 2014 | DOI: 10.1002/pip.2509

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      Nitrobenzene and PBDTTT-C-T form stable coplanar charge-transfer complexes through hydrogen bonds. Formation of the PBDTTT-C-T-C6H5NO2 complex simultaneously increases the external quantum efficiency. The underlying mechanisms of increased external quantum efficiency are attributed to the following: (i) higher lowest unoccupied molecular orbital (LUMO) of PBDTTT-C-T-C6H5NO2 for more efficient photoinduced electron transfer to the LUMO of PC71BM and (ii) efficient quenching of fluorescence in the active layers due to the formation of PBDTTT-C-T-C6H5NO2 complex.

    3. Roll-to-roll gravure printing of organic photovoltaic modules—insulation of processing defects by an interfacial layer

      Pälvi Apilo, Jussi Hiltunen, Marja Välimäki, Santtu Heinilehto, Rafal Sliz and Jukka Hast

      Article first published online: 10 MAY 2014 | DOI: 10.1002/pip.2508

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      Gravure printing as direct patterning roll-to-roll (R2R) production technology can revolutionize the design of organic photovoltaic (OPV) devices by allowing for the formation of arbitrary-shaped modules. We have analyzed the thin-film formation and its influence on OPV module performance as the gravure printing of hole transport and photoactive layers are transferred from laboratory to R2R pilot production environment. Insertion of lithium fluoride as an interfacial layer provided insulation against the detrimental pinholes formed in R2R printing process.

    4. An effective way to simultaneous realization of excellent optical and electrical performance in large-scale Si nano/microstructures

      Zengguang Huang, Sihua Zhong, Xia Hua, Xingxing Lin, Xiangyang Kong, Ning Dai and Wenzhong Shen

      Article first published online: 9 MAY 2014 | DOI: 10.1002/pip.2506

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      We report the simultaneous realization of the best optical anti-reflection and electrical passivation by combining the Si nano/microstructures with atomic-layer-deposition-Al2O3 passivation on Si wafer with the large-scale 125 × 125 mm2. The success lies in the reduced surface recombination velocities with the increase of SiNWs, because of the stronger field effect passivation for the longer and thinner SiNWs and the reduction of the pure-pyramid-textured surface recombination. This work opens a new way to realize high-efficiency SiNWs-based solar cells.

    5. Second international spectroradiometer intercomparison: results and impact on PV device calibration

      Roberto Galleano, Willem Zaaiman, Cecilia Strati, Simona Bartocci, Mauro Pravettoni, Matteo Marzoli, Raffaele Fucci, Gianni Leanza, Gianluca Timò, Alessandro Minuto, Mario Catena, Francesco Aleo, Shin Takagi, Akihito Akiyama, Rubén Nuñez and Giorgio Belluardo

      Article first published online: 9 MAY 2014 | DOI: 10.1002/pip.2511

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      We describe the results of an intercomparison of spectroradiometers of solar spectral irradiance measurements together with an assessment of the impact these results may have on the calibration of the short circuit current (Isc) of triple-junction photovoltaic devices and on the relevant spectral mismatch calculation. The spread of the resulting calibration values for the four laboratories with the lower associated standard deviations was found to be within ±4.4%, ±1% and ±7% for Top, Middle and Bottom cell, respectively.

    6. Comparison of thin epitaxial film silicon photovoltaics fabricated on monocrystalline and polycrystalline seed layers on glass

      Charles W. Teplin, Sachit Grover, Adrian Chitu, Alexander Limanov, Monical Chahal, James Im, Daniel Amkreutz, Stefan Gall, Heayoung P. Yoon, Vincenzo Lasalvia, Paul Stradins, Kim M. Jones, Andrew G. Norman, David L. Young, Howard M. Branz and Benjamin G. Lee

      Article first published online: 5 MAY 2014 | DOI: 10.1002/pip.2505

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      We fabricate and compare thin epitaxial crystal silicon solar cells on glass using three silicon seed layers to initiate epitaxy. With a single crystal seed, a 586-mV, 6.5% solar cell establishes the quality of the epitaxy process. Lower efficiencies are achieved with polycrystalline seeds formed by mixed-phase solidification (2.9%, 476-mV) and electron beam crystallization (4.1%, 551-mV), indicating the importance of a high quality seed layer.

    7. Co-optimization of SnS absorber and Zn(O,S) buffer materials for improved solar cells

      Helen Hejin Park, Rachel Heasley, Leizhi Sun, Vera Steinmann, Rafael Jaramillo, Katy Hartman, Rupak Chakraborty, Prasert Sinsermsuksakul, Danny Chua, Tonio Buonassisi and Roy G. Gordon

      Article first published online: 5 MAY 2014 | DOI: 10.1002/pip.2504

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      The effects of deposition temperature and annealing conditions of the SnS absorber layer were studied for solar cells with a structure of Mo/SnS/Zn(O,S)/ZnO/ITO. Solar-cell performance was further optimized by varying the stoichiometry of Zn(O,S). Post-deposition annealing in pure hydrogen sulfide improved crystallinity and increased the carrier mobility by one order of magnitude, and a power conversion efficiency up to 2.9% was achieved.

    8. Toward high-efficiency dye-sensitized solar cells with a photoanode fabricated via a simple water-based formulation

      Robert Lupitskyy, Venkat Kalyan Vendra, Jacek Jasinski, Delaina A. Amos, Mahendra K. Sunkara and Thad Druffel

      Article first published online: 5 MAY 2014 | DOI: 10.1002/pip.2502

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      A simple aqueous based titanium dioxide formulation for thin films is described and its performance in a dye sensitized solar cell is characterized. The concentration of a metal-organic precursor binder is optimized for current density. The films are analyzed using a number of techniques to determine how the binder concentration influences the morphology of the films.

    9. Effects of Na and MoS2 on Cu2ZnSnS4 thin-film solar cell

      Kee-Jeong Yang, Jun-Hyoung Sim, Boram Jeon, Dae-Ho Son, Dae-Hwan Kim, Shi-Joon Sung, Dae-Kue Hwang, Soomin Song, Dhruba B. Khadka, JunHo Kim and Jin-Kyu Kang

      Article first published online: 26 APR 2014 | DOI: 10.1002/pip.2500

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      The Mo-layer annealing temperature is a determining factor for the suppression of MoS2 formation and for the alternation of the Na content in the diffusion from the soda lime glass into the Mo layers. The solar cell characteristics improve in inverse proportion to the MoS2 thickness and in direct proportion to the Na content in a Mo layer before absorber precursor layer deposition. The Na reduces the defect density within the absorber and within the absorber–buffer interface.

    10. Direct evidence of enhanced chlorine segregation at grain boundaries in polycrystalline CdTe thin films via three-dimensional TOF-SIMS imaging

      Steven P. Harvey, Glenn Teeter, Helio Moutinho and Mowafak M. Al-Jassim

      Article first published online: 25 APR 2014 | DOI: 10.1002/pip.2498

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      Direct visual evidence of enhanced chlorine concentration in CdTe films after a typical CdCl2 treatment was obtained via high-resolution time-of-flight secondary ion mass spectrometry imaging. This lends support to the prevailing hypothesis that chlorine helps to passivates grain boundaries in CdTe. The data were used to estimate the grain-boundary segregation enthalpy for chlorine in CdTe.

    11. Back amorphous-crystalline silicon heterojunction (BACH) photovoltaic device with facile-grown oxide - PECVD SiNx passivation

      Zahidur R Chowdhury and Nazir P Kherani

      Article first published online: 25 APR 2014 | DOI: 10.1002/pip.2496

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      This article reports on the integration of facile native oxide-based passivation of crystalline silicon surfaces within the back amorphous-crystalline silicon heterojunction solar cell concept. The new passivation scheme consists of 1-nm thick native oxide and nominally 70-nm thick PECVD silicon nitride. The low temperature passivation scheme provides uniform high quality surface passivation and low parasitic optical absorption. The interdigitated doped hydrogenated amorphous silicon layers were deposited on the rear side of the silicon wafer using the direct current saddle field PECVD technique. A systematic analysis of a series of back amorphous-crystalline silicon heterojunction cells is carried out in order to examine the influence of the various cell parameters (interdigital gap, n-doped region width, ratio of widths of p-doped and n-doped regions) on cell performance. A photovoltaic conversion efficiency of 16.7 % is obtained for an untextured cell illuminated under AM 1.5 global spectrum (cell parameters: VOC of 641 mV, JSC of 33.7 mA-cm  − 2 and FF of 77.3 %)

    12. Failure analysis of Cu(In,Ga)Se2 photovoltaic modules: degradation mechanism of Cu(In,Ga)Se2 solar cells under harsh environmental conditions

      Dong-Won Lee, Won-Ju Cho, Jun-Kwang Song, Oh-Yun Kwon, Won-Hee Lee, Chi-Hong Park, Kyung-Eun Park, Heesoo Lee and Yong-Nam Kim

      Article first published online: 25 APR 2014 | DOI: 10.1002/pip.2497

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      This paper presents the degradation mechanism of Cu(In,Ga)Se2 (CIGS) photovoltaic modules after being exposed to high temperature and damp heat through the failure analysis. High-temperature-induced degradation and humidity-induced behaviors were revealed to increase in series resistance of the CIGS cells, due to the absorption of oxygen on the AZO, CIGS, and Mo layers. The humidity-induced degradation behavior in discolored CIGS modules was caused by the generation of Zn(OH)2 and carboxylic acids in the AZO layer.

    13. Analysis of perimeter recombination in the subcells of GaInP/GaAs/Ge triple-junction solar cells

      P. Espinet-González, I. Rey-Stolle, M. Ochoa, C. Algora, I. García and E. Barrigón

      Article first published online: 22 APR 2014 | DOI: 10.1002/pip.2501

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      Taking into account that concentrator multijunction solar cells are small solar cells, the recombination at the perimeter could be significant. Therefore, in this work, the recombination at the perimeter has been studied in the subcells that makeup a GaInP/Ga(In)As/Ge triple-junction solar cell. For that, diodes of different sizes and consequently different perimeter to area ratios have been manufactured. Their dark I–V curves have been measured, and the current density and linear current density versus voltage curves have been analyzed.

    14. Influence of Ni and Cr impurities on the electronic properties of Cu(In,Ga)Se2 thin film solar cells

      Fabian Pianezzi, Shiro Nishiwaki, Lukas Kranz, Carolin M. Sutter-Fella, Patrick Reinhard, Benjamin Bissig, Harald Hagendorfer, Stephan Buecheler and Ayodhya N. Tiwari

      Article first published online: 22 APR 2014 | DOI: 10.1002/pip.2503

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      In this work, the influence of Ni and Cr impurities on the electronic properties of CIGS thin film solar cells is investigated. Impurities were introduced into the CIGS layer by diffusion during the CIGS deposition process from a Ni or Cr precursor layer below the Mo electrical back contact. Solar cells with Ni and Cr impurities show a reduction in the device performance due to the presence of impurity related deep defect levels which we identified with admittance spectroscopy.

    15. Toward multiple maximum power point estimation of photovoltaic systems based on semiconductor theory

      Jen-Cheng Wang, Yu-Li Su, Kun-Chang Kuo, Jyh-Cherng Shieh and Joe-Air Jiang

      Article first published online: 22 APR 2014 | DOI: 10.1002/pip.2499

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      Based on the p–n junction semiconductor theory, we develop a multipoint direct-estimation (MPDE) method to directly estimate the multiple maximum power points (MPPs) of the photovoltaic (PV) systems under partially shaded conditions. The experimental results demonstrate that the proposed MPDE method can simply and accurately estimate the multiple MPPs of the PV systems under partially shaded conditions. The optimization of MPP control models and the MPP tracking for PV systems could be achieved promisingly by applying the proposed method.

    16. Cu-rich CuInSe2 solar cells with a Cu-poor surface

      Yasuhiro Aida, Valérie Depredurand, Jes K Larsen, Hitoshi Arai, Daisuke Tanaka, Masato Kurihara and Susanne Siebentritt

      Article first published online: 18 APR 2014 | DOI: 10.1002/pip.2493

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      The effects of an In–Se surface treatment of Cu-rich ([Cu]/[In] > 1) CuInSe2 absorbers were presented. An In–Se surface treatment does improve the performance of “Cu-rich” solar cells by increasing the open-circuit voltage and reducing interface recombination, which is known as the main limitation of Cu-rich devices. According to the electrical modeling, the role of the Cu-poor surface is to prevent the interface recombination simply by reducing the doping level within the space charge region.

  14. Short Communications

    1. High efficiency large area n-type front junction silicon solar cells with boron emitter formed by screen printing technology

      Kyungsun Ryu, Ajay Upadhyaya, Vijaykumar Upadhyaya, Ajeet Rohatgi and Young-Woo Ok

      Article first published online: 13 APR 2014 | DOI: 10.1002/pip.2486

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      In this paper, we report on a 19.6% (Voc of 645 mV, Jsc of 38.6 mA/cm2, and fill factor of 78.6%) efficient n-type silicon solar cell with boron emitter formed by screen printing boron dopant paste. A screen-printed boron emitter and ion-implanted phosphorus back surface field were formed simultaneously by a co-annealing process. This demonstrates the potential of screen printing technology for production of low-cost high-efficiency n-type silicon solar cells.

  15. Research Articles

    1. Electrically conductive anti-reflecting nanostructure for chalcogenide thin-film solar cells

      Ji-Hyeon Park, Tae Il Lee, Sung-Hwan Hwang, Kyeong-Ju Moon and Jae-Min Myoung

      Article first published online: 13 APR 2014 | DOI: 10.1002/pip.2488

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      Three types of CuInS2 solar cells, without ZnO NRs (reference), undoped ZnO NRs, and Al-doped ZnO NRs were prepared. Comparing to the reference, the solar cells with the NRs showed lower total reflectance and higher photovoltaic efficiency. In case of the solar cell with Al-doped ZnO NRs showed the highest photovoltaic efficiency, 11.70%.

    2. Composition and bandgap control in Cu(In,Ga)Se2-based absorbers formed by reaction of metal precursors

      Kihwan Kim, Hyeonwook Park, Gregory M. Hanket, Woo Kyoung Kim and William N. Shafarman

      Article first published online: 8 APR 2014 | DOI: 10.1002/pip.2494

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      In this work, we discuss composition and bandgap controls in CIGS-based absorbers by comparing two metal precursor reactions. A small difference in Ga composition near the top surface of an absorber was enough to significantly affect the activation energy for recombination determining VOC. A general approach to bandgap designs using Ga and S contents in the metal precursor reaction was also presented.

  16. Short Communications

    1. Positioning and doping effects on quantum dot multi-junction solar cell performance

      Alexandre W. Walker, Olivier Thériault and Karin Hinzer

      Article first published online: 2 APR 2014 | DOI: 10.1002/pip.2487

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      This short communication highlights the positioning effects of InAs quantum dot layers in the middle sub-cell of a lattice matched triple-junction solar cell on device performance under standard testing conditions using numerical modeling techniques. The simulated energy band diagrams of the control and quantum dot cells reveal insight into the reported device performance. Device efficiency is optimized by analyzing the effects of doping concentration in the quantum dot region on the short-circuit current, open-circuit voltage, and fill factor.

  17. Research Articles

    1. Passivation of photonic nanostructures for crystalline silicon solar cells

      Christos Trompoukis, Ounsi El Daif, Parikshit Pratim Sharma, Hariharsudan Sivaramakrishnan Radhakrishnan, Maarten Debucquoy, Valerie Depauw, Kris Van Nieuwenhuysen, Ivan Gordon, Robert Mertens and Jef Poortmans

      Article first published online: 1 APR 2014 | DOI: 10.1002/pip.2489

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      We report on the optical and electrical performance of photonic nanostructures, prepared by nanoimprint lithography (NIL) and two etching routes: dry (dry-NIL) and wet etching (wet-NIL). These periodic nanostructures offer a lower integrated reflectance than the industrial random pyramid texturing. Applied to 40-µm thick epitaxially grown crystalline silicon foils bonded to a glass carrier superstrate, the inverted nanopyramids (wet-NIL) showed lifetimes comparable with the non-textured reference foils (τeff = 250 µs) with a surface recombination velocity of ~8 cm/s.

    2. High temperature current–voltage characteristics of InP-based tunnel junctions

      Matthew P. Lumb, María González, Michael K. Yakes, Chaffra A. Affouda, Christopher G. Bailey and Robert J. Walters

      Article first published online: 28 MAR 2014 | DOI: 10.1002/pip.2495

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      In this paper, temperature-dependent current–voltage measurements of tunnel junctions lattice matched to InP are presented at temperatures ranging from room temperature to 220 °C. Three different designs of tunnel junction were characterized, including a bulk InAlGaAs tunnel junction, an InAlGaAs tunnel junction with InAlAs cladding layers and an InGaAs/InAlGaAs quantum-well tunnel junction. We use a non-local tunneling model, in conjunction with a numerical drift-diffusion solver, to explain the performance of the devices.

    3. Analysis of the behavior of multijunction solar cells under high irradiance Gaussian light profiles showing chromatic aberration with emphasis on tunnel junction performance

      Pilar Espinet-González, Ignacio Rey-Stolle, Carlos Algora and Iván García

      Article first published online: 28 MAR 2014 | DOI: 10.1002/pip.2491

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      The behavior of a dual-junction solar cell has been analyzed under Gaussian light profiles with different peak to average ratios in the top cell and in the bottom cell. Simulations with a three-dimensional distributed model have revealed severe disparities in the fill factor obtained depending on the light profile, which impinges the solar cell. These disparities are determined by the value of the lateral resistances through which the excess of photo-generated current is spread out.

    4. Gallium gradients in Cu(In,Ga)Se2 thin-film solar cells

      Wolfram Witte, Daniel Abou-Ras, Karsten Albe, Gottfried H. Bauer, Frank Bertram, Christian Boit, Rudolf Brüggemann, Jürgen Christen, Jens Dietrich, Axel Eicke, Dimitrios Hariskos, Matthias Maiberg, Roland Mainz, Max Meessen, Mathias Müller, Oliver Neumann, Thomas Orgis, Stefan Paetel, Johan Pohl, Humberto Rodriguez-Alvarez, Roland Scheer, Hans-Werner Schock, Thomas Unold, Alfons Weber and Michael Powalla

      Article first published online: 28 MAR 2014 | DOI: 10.1002/pip.2485

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      We present a comprehensive study on the formation, nature, and consequences of gallium gradients in Cu(In,Ga)Se2 (CIGS) solar cells deposited by the sequential and co-evaporation processes.

      The formation of gallium gradients is analyzed in real time during a selenization process and gallium gradients of CIGS layers grown by co-evaporation are analyzed by means of mass spectrometry and served as input for simulations.

      Depth-dependent lateral inhomogeneities in CIGS were investigated by luminescence measurements, and migration barriers were calculated using density functional theory.

    5. High aspect ratio electrodeposited Ni/Au contacts for GaAs-based III–V concentrator solar cells

      J. Scott Ward, Anna Duda, Daniel J. Friedman, John Geisz, William McMahon and Michelle Young

      Article first published online: 20 MAR 2014 | DOI: 10.1002/pip.2490

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      We report on a photolithographic and electro-deposition process that results in an optimized front grid structure for high efficiency multi-junction III–V concentrator solar cells operating under flux concentrations in excess of 1000 suns. When deposited on a purpose grown, heavily doped GaAs contact layer, this Ni/Au contact exhibits a low specific contact resistance of 10−4 Ohm cm2 and excellent adhesion without sintering.

    6. Interface engineering and characterization at the atomic-scale of pure and mixed ion layer gas reaction buffer layers in chalcopyrite thin-film solar cells

      Oana Cojocaru-Mirédin, Yanpeng Fu, Aleksander Kostka, Rodrigo Sáez-Araoz, Andreas Beyer, Nikolai Knaub, Kerstin Volz, Christian-Herbert Fischer and Dierk Raabe

      Article first published online: 11 MAR 2014 | DOI: 10.1002/pip.2484

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      Electrical properties, structure, and chemical composition of two different buffer/Cu(In,Ga)(Se,S)2 samples, pure In2S3 and nano-ZnS/In2S3, are investigated by means of a solar simulator, high-resolution scanning transmission electron microscopy, atom probe tomography, and X-ray photoelectron spectroscopy. The sample containing the ZnS nanodots possesses the highest efficiency, and this is explained by the Zn diffusion within the first monolayers of the absorber layer leading to a downward band bending at the surface. This configuration is very stable (Fermi level pinning at the conduction band, as observed for Cd in Cu(In,Ga)Se) and reduces the recombination rate at the interface.

    7. Tracking US photovoltaic system prices 1998–2012: a rapidly changing market

      Galen Barbose, Naïm Richard Darghouth, Samantha Weaver, David Feldman, Robert Margolis and Ryan Wiser

      Article first published online: 10 MAR 2014 | DOI: 10.1002/pip.2482

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      Analysis of more than 200,000 photovoltaic (PV) projects shows that average installed prices of US residential and commercial PV systems declined 6–7% annually during 1998–2012, reaching $4.6–$5.3/W in 2012. The capacity-weighted average price of crystalline, fixed-tilt, utility-scale PV systems declined from $6.2/W during 2007–2009 to $3.3/W in 2012. The additional system price reductions needed to expand US PV deployment will require significant reductions in non-module costs, particularly non-hardware (“soft”) costs, through market development and targeted policies.

    8. Reactive power consumption in photovoltaic inverters: a novel configuration for voltage regulation in low-voltage radial feeders with no need for central control

      Ioulia T. Papaioannou, Arturs Purvins and Charis S. Demoulias

      Article first published online: 28 FEB 2014 | DOI: 10.1002/pip.2477

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      This paper presents a novel voltage regulation in a low-voltage radial feeder at high photovoltaic (PV) deployment. A configuration for voltage control is developed, based on reactive power consumption capability in PV inverters. All the inverters are involved in the voltage regulation with no need of central control in the feeder. Finally, a sensitivity analysis assesses the effect of various PV topologies on the PV penetration level.

    9. p-CuO/n-Si heterojunction solar cells with high open circuit voltage and photocurrent through interfacial engineering

      Saeid Masudy-Panah, Goutam Kumar Dalapati, K. Radhakrishnan, Avishek Kumar, Hui Ru Tan, Elumalai Naveen Kumar, Chellappan Vijila, Cheng Cheh Tan and DongZhi Chi

      Article first published online: 23 FEB 2014 | DOI: 10.1002/pip.2483

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      Heterojunction solar cells of p-type cupric oxide (CuO) and n-type silicon (Si), p-CuO/n-Si, have been fabricated using conventional sputter and rapid thermal annealing techniques. The presence of thin interfacial layer at the heterojunction is mainly responsible for the degradation of device performance. An improvement in the Voc resulting to a record value of 509 mV and Jsc of 4 mA/cm2 with a high photocurrent of ~12 mA/cm2 was achieved through interface engineering by controlling the working pressure during sputter deposition.

    10. Metallization‒induced recombination losses of bifacial silicon solar cells

      Alexander Edler, Valentin D. Mihailetchi, Lejo J. Koduvelikulathu, Corrado Comparotto, Radovan Kopecek and Rudolf Harney

      Article first published online: 22 FEB 2014 | DOI: 10.1002/pip.2479

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      In this experimental study, we investigated the metallization‒induced recombination losses of high efficiency bifacial n‒type and p‒type crystalline Si solar cells. A metal fraction analysis was used to quantify the respectiveJ0(met) contributions and revealed that metal‒p+(boron) emitter interfaces are significantly more recombination active compared with metal‒n+ emitter interfaces. 2D modeling was employed to explain the underlying mechanism of this efficiency limiting effects.

  18. Short Communications

    1. 9.0% efficient Cu2ZnSn(S,Se)4 solar cells from selenized nanoparticle inks

      Caleb K. Miskin, Wei-Chang Yang, Charles J. Hages, Nathaniel J. Carter, Chinmay S. Joglekar, Eric A. Stach and Rakesh Agrawal

      Article first published online: 18 FEB 2014 | DOI: 10.1002/pip.2472

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      In this work, we present the synthesis of kesterite Cu2ZnSnS4 nanoparticles by a modified method of hot injection. When suspended in an ink, coated, and processed into a device, the nanoparticles obtained by this synthesis achieve a total area efficiency of 9.0%. This improvement over the previous efficiency of 7.2% is attributed to the modified synthesis, as well as fine-tuned conditions for selenizing the coated nanoparticles into a dense absorber layer.

  19. Applications

    1. Evaluation of advanced p-PERL and n-PERT large area silicon solar cells with 20.5% energy conversion efficiencies

      L. Tous, M. Aleman, R. Russell, E. Cornagliotti, P. Choulat, A. Uruena, S. Singh, J. John, F. Duerinckx, J. Poortmans and R. Mertens

      Article first published online: 15 FEB 2014 | DOI: 10.1002/pip.2478

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      In this paper, we evaluate the implementation of a simple nickel/copper/silver (Ni/Cu/Ag) plating sequence for the definition of front contacts on p-type passivated emitter and rear locally diffused (p-PERL) and n-type passivated emitter and rear totally diffused (n-PERT) large area silicon solar cells. Energy conversion efficiencies up to 20.5% (externally confirmed at FhG-ISE Callab) are presented for both cell structures on large area cells together with power-loss analysis and potential efficiency improvements based on PC1D simulations.

  20. Research Articles

    1. Temperature accelerated life test on commercial concentrator III–V triple-junction solar cells and reliability analysis as a function of the operating temperature

      P. Espinet-González, C. Algora, N. Núñez, V. Orlando, M. Vázquez, J. Bautista and K. Araki

      Article first published online: 12 FEB 2014 | DOI: 10.1002/pip.2461

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      A temperature accelerated life test on commercial concentrator lattice-matched GaInP/Ga(In)As/Ge triple-junction solar cells has been carried out. The acceleration of the aging has been accomplished by subjecting the solar cells at temperatures markedly higher than the nominal working temperature. The failure distributions across the three test temperatures have been fitted to an Arrhenius–Weibull model. The reliability functions and parameters have been obtained. We have observed that the reliability data are very sensitive to the nominal temperature condition.

    2. In-plane coupling effect on absorption coefficients of InAs/GaAs quantum dots arrays for intermediate band solar cell

      Stanko Tomić, Tomah Sogabe and Yoshitaka Okada

      Article first published online: 11 FEB 2014 | DOI: 10.1002/pip.2455

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      Schematic of idealised laterally coupled 2D quantum dot (QD) array structure made of InAs/GaAs QDs is shown. The first Brillouin zone along with few characteristic points in 2D can describe such surface geometry. Variation of the band structure throughout the 2D BZ can then be used in the analysis of QD-based intermediate band solar cell performance.

    3. Modeling a grid-connected concentrator photovoltaic system

      Ehud Strobach, David Faiman, Shlomo Kabalo, Dov Bokobza, Vladimir Melnichak, Andreas Gombert, Tobias Gerstmaier and Michael Röttger

      Article first published online: 6 FEB 2014 | DOI: 10.1002/pip.2467

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      Table 3 shows the percentage error in the hourly energy predictions of our algorithm for the first week of December 2010. Algorithm has six system parameters and includes effects of DNI, ambient temperature, wind speed, and air mass. Large early-morning and late-afternoon errors were caused by local disturbances.

    4. Two-terminal metal-inter-connected multijunction III–V solar cells

      Chieh-Ting Lin, William E. McMahon, James S. Ward, John F. Geisz, Mark W. Wanlass, Jeffrey J. Carapella, Waldo Olavarria, Emmett E. Perl, Michelle Young, Myles A. Steiner, Ryan M. France, Alan E. Kibbler, Anna Duda, Tom E. Moriarty, Daniel J. Friedman and John E. Bowers

      Article first published online: 3 FEB 2014 | DOI: 10.1002/pip.2468

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      A novel bonding method for multijunction photovoltaic devices that allows integration of dissimilar material is presented and demonstrated. The bonding interface utilizes a metal and dielectric with “pillar-array” topology to minimize optical and electrical loss. Process-related damage were addressed along with results of various bonded devices including a bonded triple-junction device with Voc = 2.70 V, Jsc = 12.66 mA/cm2, fill factor = 83.0%, and efficiency = 28.39% under the 1-sun American Society for Testing and Materials (ASTM) G173 direct spectrum.

    5. Modeling moisture ingress through polyisobutylene-based edge-seals

      Michael D. Kempe, Dhananjay Panchagade, Matthew O. Reese and Arrelaine A. Dameron

      Article first published online: 30 JAN 2014 | DOI: 10.1002/pip.2465

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      This work investigated the use of desiccant-filled polyisobutylene-based edge seals to prevent moisture ingress from the perimeter of photovoltaic modules. Through finite element models, it was found that in some of the hottest and humid climates, an edge-seal width of 1 cm can be capable of preventing moisture ingress for a 24-year module lifetime.

    6. Efficiency loss prevention in monolithically integrated thin film solar cells by improved front contact

      Joop van Deelen, Marco Barink, Lennaert Klerk, Pim Voorthuijzen and Arjan Hovestad

      Article first published online: 28 JAN 2014 | DOI: 10.1002/pip.2459

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      Modeling indicates a potential efficiency boost of 17% if thin-film solar panels are featured with a metallic grid. Variations of transparent conductive oxide sheet resistance, cell length, and grid dimensions are discussed. These parameters were optimized simultaneously to obtain the best result. Moreover, the power output as a function of these parameters is mapped out to create an insight on the interrelated sensitivities to all the parameters.

    7. Bifacial concentrator Ag-free crystalline n-type Si solar cell

      Gennady G. Untila, Tatiana N. Kost, Alla B. Chebotareva, Marat B. Zaks, Аndrey М. Sitnikov, Oleg I. Solodukha and Мaxim Z. Shvarts

      Article first published online: 28 JAN 2014 | DOI: 10.1002/pip.2471

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      Results obtained in frame of an innovative approach for fabrication of the bifacial low-concentrator thin n-type Ag-free Czochralski silicon (Cz-Si) solar cells based on indium tin oxide/(p+nn+)Cz-Si/indium fluorine oxide structure with the contact pattern of copper wire are presented in this work. The resulting solar cells showed front/rear efficiencies of 17.6–17.9%/16.7–17.0% respectively at one to three suns (bifaciality of ~95%).

    8. Luminescent down-shifting experiment and modelling with multiple photovoltaic technologies

      Diego Alonso-Álvarez, David Ross, Efthymios Klampaftis, Keith R. McIntosh, Shijun Jia, Paul Storiz, Theodore Stolz and Bryce S. Richards

      Article first published online: 25 JAN 2014 | DOI: 10.1002/pip.2462

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      We have successfully modelled the experimental performance of luminescence down shifting (LDS) on cadmium telluride, copper-indium-gallium-(di)selenide and multi-crystalline silicon solar cells with multiple luminescent materials using three theoretical approaches: ray-tracing simulations, analytical calculations and combining simple figures of merit. Each of the methods possesses certain strengths and all together provide a complete and accurate description of the LDS process. These methods can be used either as a design tool to obtain more efficient LDS layers or to assess and interpret experimental results.

    9. YieldOpt, a model to predict the power output and energy yield for concentrating photovoltaic modules

      Marc Steiner, Gerald Siefer, Thorsten Hornung, Gerhard Peharz and Andreas W. Bett

      Article first published online: 25 JAN 2014 | DOI: 10.1002/pip.2458

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      A model named YieldOpt is introduced and discussed in this paper. YieldOpt predicts the power output and energy yield of concentrator photovoltaic modules under different ambient conditions. YieldOpt combines various modeling approaches: SMARTS2 for the spectral irradiance, a finite element method and ray tracing for the optics, and a SPICE network model for the solar cell. The higher accuracy of YieldOpt compared with three empirical models in predicting the power output of five concentrator photovoltaic modules during a 1-year test period is demonstrated.

    10. Full characterization of photovoltaic modules in real operating conditions: theoretical model, measurement method and results

      Marco Pierro, Francesco Bucci and Cristina Cornaro

      Article first published online: 23 JAN 2014 | DOI: 10.1002/pip.2450

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      A theoretical model to calculate the performance ratio and losses related to spectral, reflection, temperature, irradiance effects, and nominal power variations is reported. A full characterization of modules behavior in terms of the impact of these effects on real operating conditions is provided. The model is used to compare and to explain the annual behavior of two different technologies: a multicrystalline silicon module (mc-Si) and a double junction amorphous silicon module (a-Si/DJ).

  21. Applications

    1. You have free access to this content
      A review of floating photovoltaic installations: 2007–2013

      Kim Trapani and Miguel Redón Santafé

      Article first published online: 23 JAN 2014 | DOI: 10.1002/pip.2466

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      Floating photovoltaic arrays have seen a rapid uptake in application in the last years, mainly as pontoon mounted arrays. A chronological rendition is given to allow analysis of the technology's evolution. The review highlights each of the projects (till 2013) and shows variation between them. Other research concepts, envisaged for the harsher offshore marine environments, are also outlined.

  22. Short Communications

    1. Hybrid Cd-free CIGS solar cell/TEG device with ZnO nanowires

      Ting-Jen Hsueh, Jia-Min Shieh and Yu-Ming Yeh

      Article first published online: 21 JAN 2014 | DOI: 10.1002/pip.2457

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      In this research, a novel hybrid solar electric generator device combining a CuInGaSe2 (CIGS) photovoltaic cell with nanowires light-trapping surface and a thermoelectric generator (TEG) is reported. The series-connected CIGS photovoltaic and TEG hybrid achieved a record-high efficiency of 22%. This technology provides high-efficiency energy-harvesting options.

  23. Research Articles

    1. Minimizing metastabilities in Cu(In,Ga)Se2/(CBD)Zn(S,O,OH)/i-ZnO-based solar cells

      Marie Buffière, Nicolas Barreau, Ludovic Arzel, Pawel Zabierowski and John Kessler

      Article first published online: 14 JAN 2014 | DOI: 10.1002/pip.2451

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      The present study investigates the impact on the optoelectronic behavior of the three following parameters of the Cu(In,Ga)Se2/(CBD)Zn(S,O,OH)/i-ZnO-based solar cells: (i) CIGSe surface composition; (ii) (CBD)Zn(S,O,OH) layer thickness; and (iii) i-ZnO layer resistivity. All these parameters have been found to affect the light soaking time needed to achieve optimal photovoltaic parameters, which decreased by (i) using absorbers with Cu content close to stoichiometry, (ii) increasing the buffer layer thickness, and (iii) increasing the resistivity of the i-ZnO. By optimizing these trends, stable and highly efficient Zn(S,O,OH)-buffered CIGSe solar cells have been fabricated.

  24. Applications

    1. Modelling photovoltaic modules with neural networks using angle of incidence and clearness index

      Michel Piliougine, David Elizondo, Llanos Mora-López and Mariano Sidrach-de-Cardona

      Article first published online: 11 JAN 2014 | DOI: 10.1002/pip.2449

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      A new model to simulate I-V curves of photovoltaic modules is proposed. Previous neural network models use only irradiance and module temperature, but now, the angle of incidence and the normalised clearness index are used as new inputs. The model is compared with previous methods including the procedure 1 of the IEC 60891, and the error of new model is less than 2% being a significant improvement.

  25. Research Articles

    1. A comparison between thin film solar cells made from co-evaporated CuIn1-xGaxSe2 using a one-stage process versus a three-stage process

      Pedro M.P. Salomé, Viktor Fjällström, Piotr Szaniawski, Joaquim P. Leitão, Adam Hultqvist, Paulo A. Fernandes, Jennifer P. Teixeira, Bruno P. Falcão, Uwe Zimmermann, António F. da Cunha and Marika Edoff

      Article first published online: 4 JAN 2014 | DOI: 10.1002/pip.2453

    2. Design of a polymer optical fiber luminescent solar concentrator

      Esmaeil-Hooman Banaei and Ayman F. Abouraddy

      Article first published online: 17 DEC 2013 | DOI: 10.1002/pip.2435

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      The design of a new polymeric optical fiber luminescent solar concentrator (FLSC) for two-stage light concentration is reported using low-loss submillimeter-thick polymer optical fiber with judiciously localized luminescent materials. Multiple FLSCs may be arranged on a surface to form a low-weight and mechanically flexible solar concentrating fabric for mobile energy needs. The overall optical-to-electrical conversion efficiency of the FLSC rivals that of reported flat slab luminescent solar concentrators while increasing the geometric gain, thereby potentially reducing the cost.

    3. CdS/CdTe thin-film solar cells with Cu-free transition metal oxide/Au back contacts

      Naba Raj Paudel, Chuanxiao Xiao and Yanfa Yan

      Article first published online: 17 DEC 2013 | DOI: 10.1002/pip.2446

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      This work explores the potential application of Cu-free back buffer layers at the back contact of CdS/CdTe solar cells. Thin-film CdS/CdTe cells with MoO3-x/Au,V2O5-x/Au, and WO3-x/Au back contacts exhibited efficiencies of 14.1%, 13.6%, and 12.9% under AM1.5 illumination without any anti-reflection coatings for the cells, respectively. The incorporation of the TMO buffer layers at the back contact resulted in significant improvement on open-circuit voltage (nearly 100 mV) as compared with the cells with Cu-free Au-only back contacts.

    4. Influence of cracks on the local current–voltage parameters of silicon solar cells

      Tobias M. Pletzer, Justus I. van Mölken, Sven Rißland, Otwin Breitenstein and Joachim Knoch

      Article first published online: 16 DEC 2013 | DOI: 10.1002/pip.2443

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      This paper shows a detailed analysis of the electrical influence of cracks with two different spatially resolved methods including global and local current–voltage characteristics. The main influence of cracks is an increased recombination current density in the depletion region, which is clearly shown by spatially resolved dark lock-in thermography measurements with local current–voltage investigation. This increased recombination current density affects further cell parameters such as the efficiency, which is confirmed also by the global current–voltage characteristics.

    5. Succinonitrile-based solid-state electrolytes for dye-sensitised solar cells

      Owen Byrne, Aoife Coughlan, Praveen K. Surolia and K. Ravindranathan Thampi

      Article first published online: 12 DEC 2013 | DOI: 10.1002/pip.2441

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      A plastic crystal, succinonitrile, is mixed with imidazolium salts (1,2-dimethyl-3-propylimidazoliuum iodide and 1-butyl-3-methyl imidazolium iodide) to make solid-state dye-sensitised solar cell electrolytes achieving energy conversion efficiencies of 6.3% and 5.6% at 1000 Wm−2. Common electrolyte additives (4-tert-butylpyridine, N-methyl benzimidazole, lithium iodide and guanidinium thiocyanate) inhibit the succinonitrile plastic phase with only guanidinium thiocyanate forming a room temperature solid. A simple, rapid, single-step electrolyte filling and sealing procedure suitable for continuous, high-throughput, commercial dye-sensitised solar cell manufacturing lines is outlined. Electrolytes are also tested under low light levels (200 lx) for indoor applications.

    6. Relation between light trapping and surface topography of plasma textured crystalline silicon wafers

      F. M. M. Souren, J. Rentsch and M. C. M. van de Sanden

      Article first published online: 6 DEC 2013 | DOI: 10.1002/pip.2439

      Thumbnail image of graphical abstract

      The average plane tilt angles of the different plasma textured and wet chemical textured silicon wafers, as determined from the atomic force microscope measurements, correlates directly to the weighted reflection of the textured wafers. In the case that the average plane tilt angle of a textured wafer is larger than the average plane tilt angle of the wafer, which corresponds to the tipping point, then the light trapping is effective, which corresponds to a relatively low weighted reflection.

    7. Impact of excess phosphorus doping and Si crystalline defects on Ag crystallite nucleation and growth in silver screen-printed Si solar cells

      Enrique Cabrera, Sara Olibet, Dominik Rudolph, Per Erik Vullum, Radovan Kopecek, Daniel Reinke, Carmen Herzog, Daniel Schwaderer and Gunnar Schubert

      Article first published online: 6 DEC 2013 | DOI: 10.1002/pip.2440

      Thumbnail image of graphical abstract

      The impact of phosphorus doping on screen-printed silver contacts is studied microscopically. We find that the density of Si surface-embedded Ag crystallites and their penetration depths scale proportional to the electrically inactive P. Transmission electron microscopy characterization of the excess P-doped Si crystal lattice shows that significant strain and Si bond weakening may play a major role for both Ag crystallite nucleation and growth. Furthermore, we metallize different Si crystal defects finding that Ag crystallite nucleation is defect-property dependent.

    8. Improved performance of Ge-alloyed CZTGeSSe thin-film solar cells through control of elemental losses

      Charles J. Hages, Sergej Levcenco, Caleb K. Miskin, Jan H. Alsmeier, Daniel Abou-Ras, Regan G. Wilks, Marcus Bär, Thomas Unold and Rakesh Agrawal

      Article first published online: 4 DEC 2013 | DOI: 10.1002/pip.2442

      Thumbnail image of graphical abstract

      Improved performance of nanocrystal ink-based CZTGeSSe solar cells has been achieved through minimization of bulk Ge loss from the absorber film during selenization. Here, total area power conversion efficiencies of 9.4% are reported for CZTGeSSe with 30 at.% Ge incorporation compared with 8.4% for CZTSSe. Despite elemental losses measured at the absorber film surface, improved performance of CZTGeSSe over CZTSSe is chiefly attributed to increased charge carrier lifetimes as well as reduced voltage-dependent charge carrier collection upon Ge alloying.

    9. Combinatorial study of NaF addition in CIGSe films for high efficiency solar cells

      Jessica Eid, Haifan Liang, Issam Gereige, Sang Lee and Jeroen Van Duren

      Article first published online: 4 DEC 2013 | DOI: 10.1002/pip.2419

      Thumbnail image of graphical abstract

      For sputtered Cu(In,Ga) followed by H2Se batch selenization, NaF addition results in reduced gallium content and an increase in grain size for the top portion of the CIGSe film. The addition of up to 20 nm of NaF resulted in an improvement in all relevant device parameters. The best results were found for 15 nm NaF addition, resulting in solar cells with 16.0% efficiency at open-circuit voltage (VOC) of 674 mV. A detailed analysis is provided.

    10. A CdS nanodipole solar cell

      Fang Huang, Xiangxin Liu and Wenjing Wang

      Article first published online: 25 NOV 2013 | DOI: 10.1002/pip.2432

      Thumbnail image of graphical abstract

      Convincing evidences were found to prove the existence of nanodipoles in nanodipole devices. First, we observed that the in-plane piezoresponse and analogous electric hysteresis exist at the grain boundaries due to wurtzite CdS0.956Te0.044 that varies with an external DC electrical field . Second, we also observed the formation of hexagonal CdS0.956Te0.044 particles in the annealed CdSTe film. Third, the photovoltage of the CdS nanodipole device was found to be tunable by a external DC field.

    11. Development of high-performance multicrystalline silicon for photovoltaic industry

      Y. M. Yang, A. Yu, B. Hsu, W. C. Hsu, A. Yang and C. W. Lan

      Article first published online: 26 OCT 2013 | DOI: 10.1002/pip.2437

      Thumbnail image of graphical abstract

      The figure shows the development of defects (%) and grains (photos) with ingot height for convectional (A+) and high-performance (A+++) mc-Si. As shown, with the uniform small grains at the beginning, the growth rate of defects, that is, dislocations, was significantly reduced.

    12. A new 2D model for the electrical potential in a cell stripe in thin-film solar modules including local defects

      Bart E. Pieters and Uwe Rau

      Article first published online: 26 OCT 2013 | DOI: 10.1002/pip.2436

      Thumbnail image of graphical abstract

      The performance of solar modules is strongly influenced by the presence of local defects (shunts) in the module. Numerical models that can simulate the impact of a defect on the cell performance are quite computationally intensive. We present a fast 2D model for a cell stripe based on the superposition of several analytical expressions, which can evaluate the impact of defects in a matter of seconds.

    13. Artificial neural network-based photovoltaic module temperature estimation for tropical climate of Malaysia and its impact on photovoltaic system energy yield

      Mohamed Almaktar, Hasimah Abdul Rahman, Mohammad Yusri Hassan and Ibrahim Saeh

      Article first published online: 15 OCT 2013 | DOI: 10.1002/pip.2424

      Thumbnail image of graphical abstract

      A three-layer artificial neural network-based approach for predicting photovoltaic (PV) module temperature has been developed. Using hourly measured meteorological parameters of 9 months, the data were divided into two sets: the training set and the testing set. The input parameters of the developed model were ambient temperature, solar radiation, wind speed, and relative humidity, while the output was the targeted PV module temperature. The best model was adopted based on correlation coefficient, r (95.9%), and accuracy indicators such as mean bias error (0.41), root mean square error (0.1), and mean percentage error (4.5%).

    14. Effect of lithium intercalation on the photovoltaic performances of photovoltachromic cells

      Francesco Malara, Alessandro Cannavale and Giuseppe Gigli

      Article first published online: 7 OCT 2013 | DOI: 10.1002/pip.2422

      Thumbnail image of graphical abstract

      A detailed electrochemical analysis aiming at investigating the electrochemical behavior of photovoltachromic cells. The effect of photoelectrochromic coloration on the photovoltaic performances is reported with reference to the displacement of lithium cations inside the electrolyte.

  26. Applications

    1. Design of a twin capacitive load and its application to the outdoor rating of photovoltaic modules

      Javier Muñoz, Eduardo Lorenzo, José Manuel Carrillo and Rodrigo Moretón

      Article first published online: 4 OCT 2013 | DOI: 10.1002/pip.2425

      Thumbnail image of graphical abstract

      This paper describes the design of an original twin capacitive load that is able of tracing simultaneously the I - V characteristics of two photovoltaic modules. Besides, an example of the application of this dual system to the outdoor rating of photovoltaic modules is presented, whose results have shown a good degree of repeatability.

  27. Research Articles

    1. Comparative analysis of the outdoor performance of a dye solar cell mini-panel for building integrated photovoltaics applications

      Cristina Cornaro, Simona Bartocci, Davide Musella, Cecilia Strati, Alessandro Lanuti, Simone Mastroianni, Stefano Penna, Andrea Guidobaldi, Fabrizio Giordano, Eleonora Petrolati, Thomas M. Brown, Andrea Reale and Aldo Di Carlo

      Article first published online: 4 OCT 2013 | DOI: 10.1002/pip.2426

      Thumbnail image of graphical abstract

      This work presents the results of a 3 months outdoor monitoring campaign on a dye sensitized solar cell (DSC) mini-panel positioned on a south oriented vertical plane together with a double junction amorphous silicon (a-Si) and a multi-crystalline silicon (m-Si) device at the ESTER station, University of Rome Tor Vergata. DSC yield compares favorably with that of a-Si and m-Si (12% higher than a-Si and 3% lower m-Si) especially at high solar angles of incidence confirming the suitability of this technology for building integrated photovoltaics applications.

    2. Flexible Cu(In,Ga)Se2 solar cells with reduced absorber thickness

      Patrick Reinhard, Fabian Pianezzi, Lukas Kranz, Shiro Nishiwaki, Adrian Chirilă, Stephan Buecheler and Ayodhya N. Tiwari

      Article first published online: 1 OCT 2013 | DOI: 10.1002/pip.2420

      Thumbnail image of graphical abstract

      Different modifications of the Ga double compositional grading were investigated for Cu(In,Ga)Se2 absorbers with reduced thickness (0.8–1.3 µm) grown by co-evaporation on flexible plastic substrates. Changes in open circuit voltage and fill factor are mostly related to differences in the net acceptor density or the reverse saturation current rather than changes of the double Ga grading. Highest efficiency of 16.3% was achieved for a 1.25 µm-thick absorber.

    3. All-screen-printed back-contact back-junction silicon solar cells with aluminum-alloyed emitter and demonstration of interconnection of point-shaped metalized contacts

      Robert Woehl, Marc Rüdiger, Daniel Biro and Jürgen Wilde

      Article first published online: 1 OCT 2013 | DOI: 10.1002/pip.2418

      Thumbnail image of graphical abstract

      In this paper, a screen-printed BC-BJ solar cell with aluminum-alloyed emitter on n-type Si iss presented. Three different process sequences are evaluated. An module concept is demonstrated where a point array of both polarities on the cell backside is interconnected externally on module level.

    4. Patterning of organic photovoltaic modules by ultrafast laser

      Peter Kubis, Ning Li, Tobias Stubhan, Florian Machui, Gebhard J. Matt, Monika M. Voigt and Christoph J. Brabec

      Article first published online: 21 SEP 2013 | DOI: 10.1002/pip.2421

      Thumbnail image of graphical abstract

      We demonstrate that laser patterning of organic solar cells by ultrafast laser systems (pulse length<350 fs) is an attractive process to produce photovoltaic modules with outstanding high geometric fill factors.

  28. Broader Perspectives

    1. You have free access to this content
      Environmental benefits of parking-integrated photovoltaics: a 222 kWp experience

      Lucía Serrano-Luján, Rafael García-Valverde, Nieves Espinosa, M. Socorro García-Cascales, Juan M. Sánchez-Lozano and Antonio Urbina

      Article first published online: 17 SEP 2013 | DOI: 10.1002/pip.2415

      Thumbnail image of graphical abstract
      • We have performed a life cycle assessment (LCA) on a 222 kWp cadmium telluride parking-integrated grid-connected photovoltaic facility(PV).
      • Irradiance and generated power have been monitored during 2.5 years, which delivered an average performance ratio of 0.79 and an energy payback time of 2.06 years.
      • The real case has been compared with LCA of the same size parking without PV and to a 222 kWp ground-mounted PV facility.
      • The environmental benefits of integration of the CdTe modules into the parking structure are presented and are discussed.
  29. Research Articles

    1. Improved dislocation model of silicon solar cells with the effect of front and back surface recombination velocity

      Vinay Budhraja, Bhushan Sopori, Nuggehalli Ravindra and Durgamadhab Misra

      Article first published online: 10 SEP 2013 | DOI: 10.1002/pip.2412

      Thumbnail image of graphical abstract

      The effect of front (S1) and back (S2) surface recombination velocities was included in this improved dislocation model. It is very important to include the effect of S1 and S2 because current mc-Si technology provides surface passivation by SiN:H and very effective back surface fields produced by Al alloying. The change in short-circuit current density (Jsc) value is more pronounced when S1 varies from 104 to 107 cm/s and the change in Jsc is more pronounce when S2 varies from 102 to 106 cm/s.

    2. Geometrical design of thin film photovoltaic modules for improved shade tolerance and performance

      Sourabh Dongaonkar and Muhammad A. Alam

      Article first published online: 30 AUG 2013 | DOI: 10.1002/pip.2410

      Thumbnail image of graphical abstract

      We analyze the geometrical aspects of partial shading induced reverse voltage stress in TFPV modules, using detailed circuit simulations. Based on the insights from this analysis, we propose a geometrical design approach for monolithic TFPV modules, which can improve their shade tolerance as well as efficiency. We provide a radial, and a spiral design as embodiments of this design principle, and demonstrate that it is possible to improve the module reliability and performance by simply changing cell geometry and arrangement.

    3. A PSO-based maximum power point tracking for photovoltaic systems under environmental and partially shaded conditions

      Mohammad Sarvi, Saeedeh Ahmadi and Shirzad Abdi

      Article first published online: 30 AUG 2013 | DOI: 10.1002/pip.2416

      Thumbnail image of graphical abstract

      A maximum power point tracking (MPPT) with particle swarm optimization method for photovoltaic systems is proposed, and its performance is compared with perturb and observe, improved perturb and observe, voltage-based maximum power point tracking and current-based maximum power point tracking algorithms (A sample result is shown in the figure). Simulation results confirm that proposed MPPT algorithm with more accuracy than four mentioned MPPT algorithms can track the peak power point under different insolation, temperature and partially shaded conditions.

    4. An approach to the measurement of shunt resistance of individual subcells in thin-film tandem devices

      Santolo Daliento, Vincenzo d'Alessandro, Pierluigi Guerriero and Orlando Tari

      Article first published online: 26 AUG 2013 | DOI: 10.1002/pip.2414

      Thumbnail image of graphical abstract

      A procedure based on selective illumination and relying on simple theoretical considerations is proposed to separately extract the shunt resistance of the top and bottom subcells embedded in a tandem cell.

      The method involves the measurement of the current–voltage characteristic of the tandem device by alternately keeping one of the subcells under dark conditions and is supported by numerical simulations and experimental data.

      The approach can be used for quality control, failure diagnostics, and modeling purposes.

    5. The effect of cooling press on the encapsulation properties of crystalline photovoltaic modules: residual stress and adhesion

      Heng-Yu Li, Laure-Emmanuelle Perret-Aebi, Valentin Chapuis, Christophe Ballif and Yun Luo

      Article first published online: 15 AUG 2013 | DOI: 10.1002/pip.2409

      Thumbnail image of graphical abstract

      The effect of the cooling press (CP) on the encapsulation properties of photovoltaic modules with ethylene vinyl acetate (EVA) as the encapsulant is assessed in this work. It is shown that, by applying CP, the residual stress in the encapsulated module after cooling is reduced greatly, whereas the peeling strength between front glass and EVA is enhanced. The EVA gel content remains unaffected by CP, but the high cooling rate clearly hinders the crystallization process of the EVA encapsulant during cooling.

    6. Model for simulation of energy gains using DMPPT in PV arrays

      Jorge Solórzano-Moral, Daniel Masa-Bote, Miguel Angel. Egido-Aguilera and Estefania Caamaño-Martín

      Article first published online: 8 AUG 2013 | DOI: 10.1002/pip.2413

      Thumbnail image of graphical abstract

      In this paper, a novel method for simulating energy gains in PV systems with DMPPT when in presence of shadows is presented and experimentally validated. Various simulations are run and their results presented. Results show that energy gains up to 12% can be obtained in certain situations, although normally they will be closer to 5%.

  30. Applications

    1. You have free access to this content
      Defect recognition in crystalline silicon solar cells by X-ray tomosynthesis with layer resolution

      Virginia Voland, Ulrich Hoyer, Richard Auer, Michael Salamon, Norman Uhlmann and Christoph J. Brabec

      Article first published online: 8 AUG 2013 | DOI: 10.1002/pip.2411

      Thumbnail image of graphical abstract

      In contrast to ordinary X-ray radioscopic method, the tomosynthesis technique exhibits additional depth information of the solar cells and modules. In this article, several applications of tomosynthesis for the investigation of solar cells and modules are studied. It will be shown what potential the application of X-ray and especially tomosynthesis has as quality control tool for photovoltaics.

  31. Research Articles

    1. Analytical models for the series resistance of selective emitters in silicon solar cells including the effect of busbars

      Helmut Mäckel, Gabriel Micard and Kenneth Varner

      Article first published online: 7 AUG 2013 | DOI: 10.1002/pip.2403

      Thumbnail image of graphical abstract

      Generalized analytical models for the series resistance of the front side emitter of silicon solar cells were derived. The models cover the case of two selective emitters, a different current flow in each emitter and the effect of the busbar. An excellent agreement was found between the analytical models and finite element simulations. Grid simulations of solar cells with varying selective emitters show that the change in fill factor is well described by the analytical models.


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