Advanced Energy Materials

Cover image for Vol. 1 Issue 4

July, 2011

Volume 1, Issue 4

Pages 457–698

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Editorial
    6. Review
    7. Communications
    8. Frontispiece
    9. Communications
    10. Full Papers
    11. Frontispiece
    12. Full Papers
    1. Organic Solar Cell Characterization: Direct Evaluation of Intrinsic Optoelectronic Performance of Organic Photovoltaic Cells with Minimizing Impurity and Degradation Effects (Adv. Energy Mater. 4/2011) (page 457)

      Akinori Saeki, Masashi Tsuji and Shu Seki

      Article first published online: 15 JUL 2011 | DOI: 10.1002/aenm.201190016

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      On p. 661, Akinori Saeki and coworkers investigate the correlation between organic photovoltaic cells and dynamics of transient photoconductivity by flash-photolysis time-resolved microwave conductivity. Blend ratios, annealing, impurities, and degradation effects in bulk heterojunction films consisting of P3HT and PCBM are examined, demonstrating a facile screening method to survey the potential of optoelectronic materials.

  2. Inside Front Cover

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Editorial
    6. Review
    7. Communications
    8. Frontispiece
    9. Communications
    10. Full Papers
    11. Frontispiece
    12. Full Papers
    1. Flow Batteries: Semi-Solid Lithium Rechargeable Flow Battery (Adv. Energy Mater. 4/2011) (page 458)

      Mihai Duduta, Bryan Ho, Vanessa C. Wood, Pimpa Limthongkul, Victor E. Brunini, W. Craig Carter and Yet-Ming Chiang

      Article first published online: 15 JUL 2011 | DOI: 10.1002/aenm.201190017

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      Flowable electrochemical composites power a new type of flow battery described by Yet-Ming Chiang, W. Craig Carter, and co-workers on p. 511 that, by using semi-solid electrodes based on rechargeable lithium chemistry, could provide more than ten times the energy density of aqueous flow batteries. In the image, the contents of the vial show X-ray tomography in which each color uniquely identifies a 3D continuous cluster of sub-micrometer lithium titanate spinel particles in a semi-solid “fuel.” The proposed novel flow batteries may be applicable to transportation and grid storage. Cover design by Paul Montie.

  3. Contents

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Editorial
    6. Review
    7. Communications
    8. Frontispiece
    9. Communications
    10. Full Papers
    11. Frontispiece
    12. Full Papers
    1. Contents: (Adv. Energy Mater. 4/2011) (pages 459–469)

      Article first published online: 15 JUL 2011 | DOI: 10.1002/aenm.201190018

  4. Editorial

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Editorial
    6. Review
    7. Communications
    8. Frontispiece
    9. Communications
    10. Full Papers
    11. Frontispiece
    12. Full Papers
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  5. Review

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Editorial
    6. Review
    7. Communications
    8. Frontispiece
    9. Communications
    10. Full Papers
    11. Frontispiece
    12. Full Papers
    1. Carbon Nanomaterials for Dye-Sensitized Solar Cell Applications: A Bright Future (pages 472–485)

      Lorcan J. Brennan, Michele T. Byrne, Mazhar Bari and Yurii K. Gun'ko

      Article first published online: 9 JUN 2011 | DOI: 10.1002/aenm.201100136

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      Recent advances in carbon-related nanomaterials and their applications for dye-sensitized solar cells (DSSCs) are reviewed. Carbon nanotubes and graphene are highly prospective materials to replace transparent conductive oxide (TCO) layers, as counter electrodes or absorbing layers in working photoanodes, and to improve the efficiency of the electrolyte in DSSCs. Figure reproduced with permission. Copyright The American Chemical Society, 2005.

  6. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Editorial
    6. Review
    7. Communications
    8. Frontispiece
    9. Communications
    10. Full Papers
    11. Frontispiece
    12. Full Papers
    1. Vertically Aligned Carbon Nanotubes Grown on Graphene Paper as Electrodes in Lithium-Ion Batteries and Dye-Sensitized Solar Cells (pages 486–490)

      Shisheng Li, Yanhong Luo, Wei Lv, Wanjing Yu, Sida Wu, Pengxiang Hou, Quanhong Yang, Qingbo Meng, Chang Liu and Hui-Ming Cheng

      Article first published online: 26 APR 2011 | DOI: 10.1002/aenm.201100001

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      Vertically aligned carbon nanotubes (VACNTs) are grown directly on a free-standing graphene paper (GP). The desirable carrier transport ability of the VACNTs, good conductivity and mechanical properties of the GP, and strong bonding between the VACNTs and the GP endow the hybrid structure with superior performance when utilized as the electrodes of lithium-ion batteries and dye-sensitized solar cells.

    2. High Efficiency Polymer Solar Cells with Long Operating Lifetimes (pages 491–494)

      Craig H. Peters, I. T. Sachs-Quintana, John P. Kastrop, Serge Beaupré, Mario Leclerc and Michael D. McGehee

      Article first published online: 20 APR 2011 | DOI: 10.1002/aenm.201100138

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      Organic bulk-heterojunction solar cells comprising poly[N-9'-hepta-decanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2', 1',3'-benzothiadiazole) (PCDTBT) are systematically aged and demonstrate lifetimes approaching seven years, which is the longest reported lifetime for polymer solar cells. An experimental set-up is described that is capable of testing large numbers of solar cells, holding each device at its maximum power point while controlling and monitoring the temper­ature and light intensity.

    3. Nanosilicon-Coated Graphene Granules as Anodes for Li-Ion Batteries (pages 495–498)

      Kara Evanoff, Alexandre Magasinski, Junbing Yang and Gleb Yushin

      Article first published online: 21 APR 2011 | DOI: 10.1002/aenm.201100071

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      Uniform deposition of Si and C layers on high surface area graphene produces granules with specific surface area of ∼5 m2·g−1. The anode composed of the nanocomposite particles exhibited specific capacity in excess of 2000 mAh·g−1 at a current density of 140 mA·g−1 and excellent stability for 150 cycles. The low surface area of the composite resulted in an average Coulombic efficiency in excess of 99%.

    4. The Nanoscale Morphology of a PCDTBT:PCBM Photovoltaic Blend (pages 499–504)

      Paul A. Staniec, Andrew J. Parnell, Alan D. F. Dunbar, Hunan Yi, Andrew J. Pearson, Tao Wang, Paul E. Hopkinson, Christy Kinane, Robert M. Dalgliesh, Athene M. Donald, Anthony J. Ryan, Ahmed Iraqi, Richard A. L. Jones and David G. Lidzey

      Article first published online: 28 APR 2011 | DOI: 10.1002/aenm.201100144

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      Neutron reflectivity and X-ray scattering have been used to characterise the structure of photovoltaic optimised PCDTBT:PCBM (1:4) blend films. A negative gradient of the PCBM forms spontaneously upon film casting – a fortuitous structure that is well matched for efficient charge extraction. Mild thermal annealing at 70 °C does not significantly modify the film structure, and any improvement in device efficiency is likely to be through the removal of trapped casting solvent.

  7. Frontispiece

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Editorial
    6. Review
    7. Communications
    8. Frontispiece
    9. Communications
    10. Full Papers
    11. Frontispiece
    12. Full Papers
    1. Solar Cell Architecture: Giant Efficiency Enhancement of GaAs Solar Cells with Graded Antireflection Layers Based on Syringelike ZnO Nanorod Arrays (Adv. Energy Mater. 4/2011) (page 505)

      Li-Ko Yeh, Kun-Yu Lai, Guan-Jhong Lin, Po-Han Fu, Hung-Chih Chang, Chin-An Lin and Jr-Hau He

      Article first published online: 15 JUL 2011 | DOI: 10.1002/aenm.201190019

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      Architecture innovations are crucial for enhancing the efficiency of solar cells (SCs), which depends on the probability of an incident photon being absorbed. GaAs SCs employing syringe-like ZnO nanorods, providing a smooth index transition from air to the SC surface, show an efficiency boost of 32%. This light-harvesting nanostructure is compatible with existing technology and applicable for various SCs, report Jr-Hau He and co-workers.

  8. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Editorial
    6. Review
    7. Communications
    8. Frontispiece
    9. Communications
    10. Full Papers
    11. Frontispiece
    12. Full Papers
    1. Giant Efficiency Enhancement of GaAs Solar Cells with Graded Antireflection Layers Based on Syringelike ZnO Nanorod Arrays (pages 506–510)

      Li-Ko Yeh, Kun-Yu Lai, Guan-Jhong Lin, Po-Han Fu, Hung-Chih Chang, Chin-An Lin and Jr-Hau He

      Article first published online: 20 MAY 2011 | DOI: 10.1002/aenm.201100025

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      An effective antireflection coating of syringelike ZnO NRAs is demonstrated for GaAs solar cells. Energy conversion efficiency is significantly enhanced by up to 32%. GaAs is focussed on as a model system, but the hydrothermal growth of syringelike ZnO nanostructures is readily compatible with the existing processes in the photovoltaic industry, and highly applicable for various types of solar cells.

    2. Semi-Solid Lithium Rechargeable Flow Battery (pages 511–516)

      Mihai Duduta, Bryan Ho, Vanessa C. Wood, Pimpa Limthongkul, Victor E. Brunini, W. Craig Carter and Yet-Ming Chiang

      Article first published online: 20 MAY 2011 | DOI: 10.1002/aenm.201100152

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      A new kind of flow battery is fueled by semi-solid suspensions of high-energy-density lithium storage compounds that are electrically ‘wired’ by dilute percolating networks of nanoscale conductor particles. Energy densities are an order of magnitude greater than previous flow batteries; new applications in transportation and grid-scale storage may result.

    3. Differential Resistance Analysis of Charge Carrier Losses in Organic Bulk Heterojunction Solar Cells: Observing the Transition from Bimolecular to Trap-Assisted Recombination and Quantifying the Order of Recombination (pages 517–522)

      Wei Lin Leong, Sarah R. Cowan and Alan J. Heeger

      Article first published online: 11 MAY 2011 | DOI: 10.1002/aenm.201100196

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      Differential resistance analysis has been shown to be effective at studying the charge carrier losses in bulk heterojunction solar cells. The variations of differential resistance with light intensity and Voc provide strong evidence for the identification of the recombination kinetics, revealing bimolecular as the dominating recombination mechanism in PCDTBT:PC60BM system and showing an evolution to trap-assisted recombination in presence of PC84BM trap states.

    4. Silicon–Carbon Nanotube Coaxial Sponge as Li-Ion Anodes with High Areal Capacity (pages 523–527)

      Liangbing Hu, Hui Wu, Yifan Gao, Anyuan Cao, Hongbian Li, James McDough, Xing Xie, Min Zhou and Yi Cui

      Article first published online: 15 JUL 2011 | DOI: 10.1002/aenm.201100056

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      Highly porous, conductive Si-CNT sponge-like structures with a large areal mass loading are demonstrated as effective Li-ion battery anode materials. Nanopore formation and growth in the Si shell has been identified as the primary failure mode of the Si-CNT sponge anode, and the formation of such nanopores can be minimized by tuning the cutoff voltages. In conjunction with experiments, a theoretical analysis was carried out to explain the pore formation mechanism.

    5. A p-Type Quantum Dot/Organic Donor:Acceptor Solar-Cell Structure for Extended Spectral Response (pages 528–533)

      Hsiang-Yu Chen, Jianhui Hou, Smita Dayal, Lijun Huo, Nikos Kopidakis, Matthew C. Beard and Joseph M. Luther

      Article first published online: 21 JUN 2011 | DOI: 10.1002/aenm.201100190

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      A coupled PbS quantum dot film and a PSBTBT:PCBM bulk heterojunction layer contribute comparable photocurrent in a new stacked solar-cell architecture with sensitivity in the near infrared and an efficiency >4%. With a focus on the energy level alignment between components, time-resolved microwave photoconductivity is used to elucidate the charge transport pathways for electrons and holes.

    6. TaC Nanowire/Activated Carbon Microfiber Hybrid Structures from Bamboo Fibers (pages 534–539)

      Xinyong Tao, Jun Du, Yiping Li, Yingchao Yang, Zheng Fan, Yongping Gan, Hui Huang, Wenkui Zhang, Lixin Dong and Xiaodong Li

      Article first published online: 17 JUN 2011 | DOI: 10.1002/aenm.201100191

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      Hybrid structures consisting of TaC nanowires and activated carbon microfibers are synthesized via a carbothermal method using bamboo fibers as both the carbon source and the template. The nanowires exhibit a Young's modulus of 364.7 GPa and low electrical resistivity of 63.6 μΩ·cm. These unique hierarchical heterostructures of TaC/C demonstrate remarkable energy storage capabilities as a new promising material for high performance supercapacitors.

    7. Unsymmetrical Triphenylamine-Oligothiophene Hybrid Conjugated Systems as Donor Materials for High-Voltage Solution-Processed Organic Solar Cells (pages 540–545)

      Emilie Ripaud, Théodulf Rousseau, Philippe Leriche and Jean Roncali

      Article first published online: 12 APR 2011 | DOI: 10.1002/aenm.201100065

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      The synthesis of unsymmetrical triphenylamine-oligothiophene hybrid conjugated systems bearing dicyanovinyl electron acceptor end-groups is presented. When used as molecular donor materials in solution-processed bulk heteroj­unction solar cells, these compounds lead to efficient devices with very high open-circuit voltages.

    8. A Quasi-Inverse Opal Layer Based on Highly Crystalline TiO2 Nanoparticles: A New Light-Scattering Layer in Dye-Sensitized Solar Cells (pages 546–550)

      Se-Hoon Han, Sangwook Lee, Hyunjung Shin and Hyun Suk Jung

      Article first published online: 5 MAY 2011 | DOI: 10.1002/aenm.201100084

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      Bifunctional opals in dye-sensitized solar cells (DSSCs): A quasi-inverse opal architecture comprising highly crystalline TiO2 nanoparticles acts as a light-scattering layer, which improves the spectral response of DSSCs in the long-wavelength region, and it acts as an active layer, which increases the photoinduced electrons in the short-wavelength region.

    9. High-Performance Supercapacitors Based on Hierarchically Porous Graphite Particles (pages 551–556)

      Zheng Chen, Jing Wen, Chunzhu Yan, Lynn Rice, Hiesang Sohn, Meiqing Shen, Mei Cai, Bruce Dunn and Yunfeng Lu

      Article first published online: 1 JUN 2011 | DOI: 10.1002/aenm.201100114

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      Hierarchically porous graphite particles are synthesized using a continuous, scalable aerosol approach. The unique porous graphite architecture provides the particles with high surface area, fast ion transportation, and good electronic conductivity, which endows the resulting supercapacitors with high energy and power densities. This work provides a new material platform for high-performance supercapacitors with high packing density, and is adaptable to battery electrodes, fuel-cell catalyst supports, and other applications.

    10. Synthesis and Characterization of a Copolymer Based on Thiazolothiazole and Dithienosilole for Polymer Solar Cells (pages 557–560)

      Maojie Zhang, Xia Guo and Yongfang Li

      Article first published online: 17 MAY 2011 | DOI: 10.1002/aenm.201100193

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      A new D–A copolymer,PDTSTTz, has been synthesized based on a dithienosilole donor unit and a thiazolothiazole acceptor unit for application as a donor material in polymer solar cells (PSCs). The power conversion efficiency of the PSC based on PDTSTTz/PC70BM (1:1, w/w) with thermal annealing at 100 °C for 15 min reached 5.59% with JSC = 11.9 mA cm−2, VOC = 0.77 V, and FF = 0.61, under the illumination of AM1.5, 100 mW cm−2.

    11. ZnS Nanodot Film as Defect Passivation Layer for Cu(In,Ga)(S,Se)2 Thin-Film Solar Cells Deposited by Spray-ILGAR (Ion-Layer Gas Reaction) (pages 561–564)

      Yanpeng Fu, Nicholas A. Allsop, Sophie E. Gledhill, Tristan Köhler, Martin Krüger, Rodrigo Sáez-Araoz, Ulrike Blöck, Martha Ch. Lux-Steiner and Christian-Herbert Fischer

      Article first published online: 5 MAY 2011 | DOI: 10.1002/aenm.201100146

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      Wurtzite-phase ZnS nanodot films with controllable dot density can be prepared at low temperature by a technique known as Spray-ILGAR (ILGAR = ion-layer gas reaction), without organic surfactant. ZnS nanodots covered with homogenous In2S3 (as the point-contact bridge) act as a defect passivation layer and form a structured buffer layer. This ZnS/In2S3 buffer improves cell efficiencies by up to about 1%–1.5% compared to reference cells with a pure ILGAR In2S3 buffer.

    12. A 4% Efficient Organic Solar Cell Using a Fluorinated Fused Subphthalocyanine Dimer as an Electron Acceptor (pages 565–568)

      Bregt Verreet, Barry P. Rand, David Cheyns, Afshin Hadipour, Tom Aernouts, Paul Heremans, Anaïs Medina, Christian G. Claessens and Tomas Torres

      Article first published online: 16 JUN 2011 | DOI: 10.1002/aenm.201100137

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      Planar bilayer organic solar cells with a fluorinated fused subphthalocyanine dimer (FSubPcDimer) as an acceptor and chloroboron (III) subphthalocyanine (SubPc) as a donor obtain a 60% higher Jsc compared to cells using C60 as an acceptor, resulting in a power conversion efficiency of 4%. This is obtained thanks to the important contribution to the photocurrent of the low-bandgap FSubPcDimer.

    13. Enhanced Open-Circuit Photopotential in Quasi-Solid-State Dye-Sensitized Solar Cells Based on Polymer Redox Electrolytes Filled with Anodic Titania Nanotubes (pages 569–572)

      Thomas Stergiopoulos, Evangelia Rozi, Robert Hahn, Patrik Schmuki and Polycarpos Falaras

      Article first published online: 17 JUN 2011 | DOI: 10.1002/aenm.201100168

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      An overall power-conversion efficiency of 5.4% is achieved at 1 sun AM1.5G by novel composite polymer electrolytes, prepared by filling them with titania nanotubes (NTs) produced by electrochemical anodization. The TiO2 NTs are transformed into a powder that is further incorporated in a polymer redox electrolyte. The addition of the filler increases the open-circuit photopotential of the dye-sensitized solar cell by more than 80 mV, reaching values of up to 843 mV.

    14. Lamellar Titanates: A Breakthrough in the Search for New Solid Oxide Fuel Cell Anode Materials Operating on Methane (pages 573–576)

      Cédric Périllat-Merceroz, Pascal Roussel, Rose-Noëlle Vannier, Patrick Gélin, Sébastien Rosini and Gilles Gauthier

      Article first published online: 3 MAY 2011 | DOI: 10.1002/aenm.201100107

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      Decreasing the dimensionality of the LaxSr1–xTiOmath image family structure from 3D to 2D by increasing the La content greatly enhances the electrochemical performance of the material as an SOFC anode. This is attested to by the strong decrease in the polarization resistance values deduced from the complex impedance spectra (Nyquist plot) recorded at 900 °C in H2/H2O(3%) on a symmetrical cell.

  9. Full Papers

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Editorial
    6. Review
    7. Communications
    8. Frontispiece
    9. Communications
    10. Full Papers
    11. Frontispiece
    12. Full Papers
    1. Thermoelectric Property Studies on Cu-Doped n-type CuxBi2Te2.7Se0.3 Nanocomposites (pages 577–587)

      Wei-Shu Liu, Qinyong Zhang, Yucheng Lan, Shuo Chen, Xiao Yan, Qian Zhang, Hui Wang, Dezhi Wang, Gang Chen and Zhifeng Ren

      Article first published online: 9 JUN 2011 | DOI: 10.1002/aenm.201100149

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      Combining high energy ball milling and hot pressing, a significant enhancement on thermoelectric figure-of-merit (ZT) has been reported in p-type Bi0.4Sb1.6Te3 nanocomposites, however the reproducibility from batch to batch is unsatisfactory. Improved reproducibility can be achieved by introducing a concentration of 0.01 Cu per Bi2Te2.7Se0.3 to give Cu0.01Bi2Te2.7Se0.3 samples. A peak ZT value of 0.99 is obtained in Cu0.01Bi2Te2.7Se0.3 samples without texturing. When textured by re-pressing, the peak ZT can be increased to 1.06. Aging in air for over 5 months does not cause deterioration but further improved the peak ZT to 1.10.

    2. Selective Dye Loading at the Heterojunction in Polymer/Fullerene Solar Cells (pages 588–598)

      Satoshi Honda, Hideo Ohkita, Hiroaki Benten and Shinzaburo Ito

      Article first published online: 26 APR 2011 | DOI: 10.1002/aenm.201100094

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      Selective dye loading at the polymer/fullerene interface improves the photocurrent density and power conversion efficiency of ternary blend bulk heterojunction solar cells. Such interfacial segregation of NIR-dye molecules in ternary blend films can be rationally explained in terms of the surface energy of each component and the crystallization of polymer enhanced by annealing.

    3. Efficient Semi-Transparent Organic Solar Cells with Good Transparency Color Perception and Rendering Properties (pages 599–603)

      Alexander Colsmann, Andreas Puetz, Andreas Bauer, Jonas Hanisch, Erik Ahlswede and Uli Lemmer

      Article first published online: 3 MAY 2011 | DOI: 10.1002/aenm.201000089

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      Besides a good transparencycolor perception, semi-transparent organic solar cells for window integration require good transparency color rendering properties to allow for convenient scene lighting. Devices comprising the polymer/fullerene blend PSBTBT:PC70BM exhibit high power conversion efficiencies and remarkably neutral light modulation properties in different illumination scenarios, making them suitable for applications in automotives and buildings.

    4. Low-Temperature Behaviour of Charge Transfer Excitons in Narrow-Bandgap Polymer-Based Bulk Heterojunctions (pages 604–609)

      Dorota Jarzab, Fabrizio Cordella, Jio Gao, Markus Scharber, Hans-Joachim Egelhaaf and Maria Antonietta Loi

      Article first published online: 3 MAY 2011 | DOI: 10.1002/aenm.201100083

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      Photoluminescence studies of the charge transfer exciton emission from a narrow-bandgap polymer-based bulk heterojunction are reported. The quantum yield of this emission is as high as 0.03%. Based on the low temperature results the role of the charge transfer excitons and the possible pathways to populate them are identified.

    5. Effect of Charge Recombination on the Fill Factor of Small Molecule Bulk Heterojunction Solar Cells (pages 610–617)

      Yuan Zhang, Xuan-Dung Dang, Chunki Kim and Thuc-Quyen Nguyen

      Article first published online: 9 JUN 2011 | DOI: 10.1002/aenm.201100040

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      Solution-processed organic BHJ solar cells based on DPP(TBFu)2 and P3HT blended with PCBM behave differently under various irradiation intensities. Small molecule-based solar cells show up to 5.2% power conversion efficiency and a high fill factor at low light intensity. At 100 mW cm−2 illumination, the efficiency and fill factor decrease, resulting in stronger power loss. Impedance spectroscopy at various light intensities reveals that high charge recombination is the cause of the low fill factor.<?br?>

    6. Development of CO2 Protective Layers by Spray Pyrolysis for Ceramic Oxygen Transport Membranes (pages 618–625)

      Iván García-Torregrosa, M. Pilar Lobera, Cecilia Solís, Pedro Atienzar and José M. Serra

      Article first published online: 15 JUL 2011 | DOI: 10.1002/aenm.201100169

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      Ceria-based protective 0.4 μm thick layers are deposited on La0.6Sr0.4Co0.2Fe0.8O3-δ membranes by air blast spray pyrolysis. Smooth crack-free dense coatings are obtained with high crystallinity in the as-deposited state and allowing an increase of membrane stability in CO2 environments, although the oxygen flux is slightly reduced due to the limited ambipolar conductivity of doped ceria.

    7. Design Principles of FRET-Based Dye-Sensitized Solar Cells with Buried Quantum Dot Donors (pages 626–633)

      Stella Itzhakov, Sophia Buhbut, Elad Tauber, Thomas Geiger, Arie Zaban and Dan Oron

      Article first published online: 9 JUN 2011 | DOI: 10.1002/aenm.201100110

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      The photophysics of FRET-based dye-sensitized solar cells, in which QD donor “antennas” are incorporated into the solid titania electrode, is studied. Time-resolved photoluminescence measurements are used to directly show high FRET efficiencies. The various parameters governing the FRET efficiency and the requirements for high efficiency FRET-based cells, as well as the contribution of the radiative energy transfer to the internal quantum efficiency are discussed.

    8. Silica Nanohybrid Membranes with High CO2 Affinity for Green Hydrogen Purification (pages 634–642)

      Cher Hon Lau, Songlin Liu, Donald R. Paul, Jianzhong Xia, Yan-Ching Jean, Hongmin Chen, Lu Shao and Tai-Shung Chung

      Article first published online: 14 JUN 2011 | DOI: 10.1002/aenm.201100195

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      Organic-inorganic materials synthesized from sol-gel chemistry yield well-dispersed inorganic nanoclusters. Using a simple, acid-catalyzed process, high CO2 affinity gas separation membranes are fabricated from polyether diamines and alkoxysilanes. The CO2 permeability of these membranes can reach 1950 Barrer while CO2/H2 and CO2/N2 selectivities are 11 and 56, respectively. Such membranes can potentially replace current high carbon footprint techniques while achieving high CO2/light gas separation factors in a sustainable manner.

    9. Enhancement in Thermoelectric Figure-Of-Merit of an N-Type Half-Heusler Compound by the Nanocomposite Approach (pages 643–647)

      Giri Joshi, Xiao Yan, Hengzhi Wang, Weishu Liu, Gang Chen and Zhifeng Ren

      Article first published online: 3 MAY 2011 | DOI: 10.1002/aenm.201100126

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      25% enhancement over the previously reported highest value is achieved in the thermoelectric figure-of-merit (ZT) of an n-type half-Heusler material, using a nanocomposite approach. The nanostructured samples are prepared by ball-milling arc-melted ingots into nanopowders and hot-pressing the powders into dense bulk samples. The ZT enhancement mainly comes from the reduction of thermal conductivity.

    10. Sb-Doped SnO2 Hollow Spheres Offering Micro- and Nanoporosity in Fuel Cell Electrode Structures (pages 648–654)

      Jens Suffner, Sebastian Kaserer, Horst Hahn, Christina Roth and Frank Ettingshausen

      Article first published online: 16 MAY 2011 | DOI: 10.1002/aenm.201100077

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      Sb-doped SnO2 (ATO) with a novel hollow sphere morphology can be synthesized by ultrasonic spray pyrolysis and used as an alternative support material in fuel cell cathodes. The unique morphology leads to a porous electrode structure with a controlled nanoscale and microscale porosity. This structure offers efficient mass transport and is believed to prevent the collapse of the electrode structure during operation.

    11. Electronic Trap States in Methanofullerenes (pages 655–660)

      Julia Schafferhans, Carsten Deibel and Vladimir Dyakonov

      Article first published online: 20 MAY 2011 | DOI: 10.1002/aenm.201100175

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      Significant differences in activation energy are observed when the electronic trap states in the fullerene derivatives PC61BM, bisPC61BM, and PC71BM, commonly used as electron acceptors in organic solar cells, are investigated by means of thermally stimulated current measurements. The results are discussed with respect to the performance of organic solar cells.

    12. Direct Evaluation of Intrinsic Optoelectronic Performance of Organic Photovoltaic Cells with Minimizing Impurity and Degradation Effects (pages 661–669)

      Akinori Saeki, Masashi Tsuji and Shu Seki

      Article first published online: 16 MAY 2011 | DOI: 10.1002/aenm.201100143

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      A correlation between the photovoltaic performance and dynamics of transient photoconductivity is investigated by non-contact flash-photolysis time-resolved microwave conductivity (FP-TRMC). We examined the blend ratio, process, and impurity and degradation effects in bulk heterojunction films consisting of poly(3-hexylthiophene) (P3HT) and methanofullerene (PCBM). The good correlation revealed is expected to be useful as a facile screening method to survey the potential of optoelectronic materials.

  10. Frontispiece

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Editorial
    6. Review
    7. Communications
    8. Frontispiece
    9. Communications
    10. Full Papers
    11. Frontispiece
    12. Full Papers
    1. PEM Fuel Cells: Integrated High-Efficiency Pt/Carbon Nanotube Arrays for PEM Fuel Cells (Adv. Energy Mater. 4/2011) (page 670)

      Weimin Zhang, Andrew I. Minett, Mei Gao, Jie Zhao, Joselito M. Razal, Gordon G. Wallace, Tony Romeo and Jun Chen

      Article first published online: 15 JUL 2011 | DOI: 10.1002/aenm.201190020

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      Improved catalyst utilization at the ORR electrode in PEM fuel cells is of critical importance for improving power and energy output. Functionalized, aligned carbon nanotube architectures provide a robust platform for improved catalytic utilization for the reduction of oxygen molecules, report Gordon Wallace, Jun Chen, and co-workers.

  11. Full Papers

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Editorial
    6. Review
    7. Communications
    8. Frontispiece
    9. Communications
    10. Full Papers
    11. Frontispiece
    12. Full Papers
    1. Integrated High-Efficiency Pt/Carbon Nanotube Arrays for PEM Fuel Cells (pages 671–677)

      Weimin Zhang, Andrew I. Minett, Mei Gao, Jie Zhao, Joselito M. Razal, Gordon G. Wallace, Tony Romeo and Jun Chen

      Article first published online: 17 MAY 2011 | DOI: 10.1002/aenm.201100092

      Thumbnail image of graphical abstract

      Membrane electrode assembly of a proton-exchange fuel cell utilizing platinum- loaded vertically aligned carbon nanotube (CNT) arrays shows higher fuel-cell performance than a conventional fuel cell with carbon black counterparts. Loading of platinum electrocatalysts onto the nanotube arrays is straightforward and affords higher efficiency wherein the optimum Pt loading is achieved at a very low loading of 0.15 mg Pt cm−2 of aligned CNTs array.

    2. Superior CO2 Adsorption Capacity on N-doped, High-Surface-Area, Microporous Carbons Templated from Zeolite (pages 678–683)

      Yongde Xia, Robert Mokaya, Gavin S. Walker and Yanqiu Zhu

      Article first published online: 25 MAY 2011 | DOI: 10.1002/aenm.201100061

      Thumbnail image of graphical abstract

      A superior CO2 uptake capacity of up to 4.4 mmol g−1 is exhibited at ambient temperature and pressure by zeolite-templated, high-surface-area, microporous N-doped carbon, along with an initial CO2 adsorption energy of 36 kJ mol−1 at lower coverage and 20 kJ mol−1 at higher coverage.

    3. Ellipsometric Investigation of the Shape of Nanodomains in Polymer/Fullerene Films (pages 684–689)

      Sebastian Engmann, Vida Turkovic, Gerhard Gobsch and Harald Hoppe

      Article first published online: 17 JUN 2011 | DOI: 10.1002/aenm.201100109

      Thumbnail image of graphical abstract

      Shaping up: Ellipsometric measurements are presented for the determination of the shape of fullerene inclusions within a polymer/fullerene blend. In as-cast films the inclusions are spherical for small fullerene concentrations. Above 40 wt% fullerene, the inclusions form a percolation network, accompanied by a gradual loss of optical anisotropy.

    4. High Performance Organic Photovoltaic Cells Using Polymer-Hybridized ZnO Nanocrystals as a Cathode Interlayer (pages 690–698)

      Sae Byeok Jo, Ji Hwang Lee, Myungsun Sim, Min Kim, Jong Hwan Park, Yeong Suk Choi, Yungi Kim, Soo-Ghang Ihn and Kilwon Cho

      Article first published online: 14 JUN 2011 | DOI: 10.1002/aenm.201100154

      Thumbnail image of graphical abstract

      The hybridization of ZnO nanocrystals with insulating polymers provides multi­functional interfacial layers for organic photovoltaics. The addition of an insulating polymer permits control over the morphology of ZnO crystal domain, the interfacial energy level alignment and the optical electrical field redistribution. The power conversion efficiencies of devices with these tuned hybrid insertion layers can be increased to 4.4%, with a high fill factor of 0.69.

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