Advanced Energy Materials

Cover image for Vol. 1 Issue 5

October, 2011

Volume 1, Issue 5

Pages 701–969

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Communications
    7. Full Papers
    8. Frontispiece
    9. Full Papers
    1. Organic Solar Cell Characterization: Electronically Monodisperse Single-Walled Carbon Nanotube Thin Films as Transparent Conducting Anodes in Organic Photovoltaic Devices (Adv. Energy Mater. 5/2011) (page 701)

      Timothy P. Tyler, Ryan E. Brock, Hunter J. Karmel, Tobin J. Marks and Mark C. Hersam

      Version of Record online: 16 SEP 2011 | DOI: 10.1002/aenm.201190021

      Thumbnail image of graphical abstract

      The image depicts a series of electronic-type sorted single-walled carbon nanotubes suspended in solution. The rays of light emanating from behind the samples is suggestive of the solar energy that these materials help capture in organic photovoltaic cells. On p. 785 Mark Hersam and co-workers demonstrate that the green metallic solutions yield transparent electrodes with improved stability compared to their red semiconducting counterparts.

  2. Inside Front Cover

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Communications
    7. Full Papers
    8. Frontispiece
    9. Full Papers
    1. 3D Transparent Conducting Oxides: Nanowire-Based Three-Dimensional Transparent Conducting Oxide Electrodes for Extremely Fast Charge Collection (Adv. Energy Mater. 5/2011) (page 702)

      Jun Hong Noh, Hyun Soo Han, Sangwook Lee, Jin Young Kim, Kug Sun Hong, Gil-Sang Han, Hyunjung Shin and Hyun Suk Jung

      Version of Record online: 16 SEP 2011 | DOI: 10.1002/aenm.201190022

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      Efficient charge collection is important for achieving high conversion efficiency in solar cells. On p. 829 Hyun Suk Jung, Jin Young Kim, and coworkers show that three-dimensional transparent conducting oxide (TCO) substrates based on aligned In-Sn-O (ITO) nanowire arrays provide a universal strategy for improving charge collection properties of solar cells by significantly reducing the charge travel distance in the active material.

  3. Contents

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

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Communications
    7. Full Papers
    8. Frontispiece
    9. Full Papers
    1. Thermoelectric Nanostructures: From Physical Model Systems towards Nanograined Composites (pages 713–731)

      Kornelius Nielsch, Julien Bachmann, Johannes Kimling and Harald Böttner

      Version of Record online: 16 SEP 2011 | DOI: 10.1002/aenm.201100207

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      Nanostucturing is considered to be a promising strategy for thermoelectric materials with high efficiency (Z·T). Novel nanostructures such as multilayers, nanowires and nanomeshes based on traditional materials and silicon are of great interest for fundamental research. Nanograined bulk-materials, based on scalable synthesis processes, are thought to be worth implementing in outperforming standard devices for room temperature and high temperature applications.

  5. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Communications
    7. Full Papers
    8. Frontispiece
    9. Full Papers
    1. Earth-Abundant Element Photovoltaics Directly from Soluble Precursors with High Yield Using a Non-Toxic Solvent (pages 732–735)

      Wooseok Ki and Hugh W. Hillhouse

      Version of Record online: 10 AUG 2011 | DOI: 10.1002/aenm.201100140

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      A new chemical route to Cu2ZnSn(SxSe1-x)4 based thin film solar cells has been developed using spin coating of commercially available molecular precursors from an environmentally friendly non-toxic solvent. 4.1% efficiency solar cells were achieved after selenization of Cu2ZnSnS4. This technique could provide simple, facile, and reproducible fabrication for efficient and large area solar cells.

    2. A Hierarchically Nanostructured Composite of MnO2/Conjugated Polymer/Graphene for High-Performance Lithium Ion Batteries (pages 736–741)

      Chun Xian Guo, Min Wang, Tao Chen, Xiong Wen Lou and Chang Ming Li

      Version of Record online: 4 AUG 2011 | DOI: 10.1002/aenm.201100223

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      A hierarchically nanostructured composite of MnO2/conjugated polymer/graphene is designed and fabricated for lithium ion batteries. The composite can produce a reversible capacity more than ten times that of plain MnO2-based devices. The described approach can be used to create desired hierarchically nanostructured composite electrodes for broad applications in energy conversion/storage systems.

    3. A New Approach to Solar Hydrogen Production: a ZnO–ZnS Solid Solution Nanowire Array Photoanode (pages 742–747)

      Hao Ming Chen, Chih Kai Chen, Ru-Shi Liu, Ching-Chen Wu, Wen-Sheng Chang, Kuei-Hsien Chen, Ting-Shan Chan, Jyh-Fu Lee and Din Ping Tsai

      Version of Record online: 16 AUG 2011 | DOI: 10.1002/aenm.201100246

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      A ZnO–ZnS solid solution nanowire array photoanode is developed based on an alternative sensitization of a ZnO–ZnS solid solution nanowire array for solar hydrogen generation with considerably enhanced photocurrent – more than 195% greater compared to pristine ZnO nanowires. This solid solution structure demonstrates a better photoactivity enhancement effect than traditional quantum dot sensitization, as well as allowing hydrogen generation.

    4. Iron Chalcogenide Photovoltaic Absorbers (pages 748–753)

      Liping Yu, Stephan Lany, Robert Kykyneshi, Vorranutch Jieratum, Ram Ravichandran, Brian Pelatt, Emmeline Altschul, Heather A. S. Platt, John F. Wager, Douglas A. Keszler and Alex Zunger

      Version of Record online: 10 AUG 2011 | DOI: 10.1002/aenm.201100351

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      An integrated computational and experimental study of FeS2 pyrite reveals that phase coexistence is an important factor limiting performance as a thin-film solar absorber. This phase coexistence is suppressed with the ternary materials Fe2SiS4 and Fe2GeS4, which also exhibit higher band gaps than FeS2. Thus, the ternaries provide a new entry point for development of thin-film absorbers and high-efficiency photovoltaics.

    5. Interface Energy Controlled Thermodynamics of Nanoscale Metal Hydrides (pages 754–758)

      Lennard P.A. Mooij, Andrea Baldi, Christiaan Boelsma, Kun Shen, Marnix Wagemaker, Yevheniy Pivak, Herman Schreuders, Ronald Griessen and Bernard Dam

      Version of Record online: 16 AUG 2011 | DOI: 10.1002/aenm.201100316

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      Nanoconfined MgH2 is destabilized compared to its bulk counterpart because of an interface energy effect. The hydrogen equilibrium pressure increases by an order of magnitude when decreasing the Mg layer thickness from 10 to 2 nm. This relates to an interface energy change of 0.3 J m−2.

    6. Graphite-Silicon-Polyacrylate Negative Electrodes in Ionic Liquid Electrolyte for Safer Rechargeable Li-Ion Batteries (pages 759–765)

      Naoaki Yabuuchi, Keiji Shimomura, Yukako Shimbe, Tomoaki Ozeki, Jin-Young Son, Hiroshi Oji, Yasushi Katayama, Takashi Miura and Shinichi Komaba

      Version of Record online: 12 AUG 2011 | DOI: 10.1002/aenm.201100236

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      Graphite/silicon composite electrodes are prepared with PANa polymer as a binder. Morphological characters and electrode performance are compared with those of PVdF. The PANa layer behaves like SEI at the interface with ionic liquid, resulting in the highly reversible electrode performance.

    7. Enhanced Power Conversion Efficiency in PCDTBT/PC70BM Bulk Heterojunction Photovoltaic Devices with Embedded Silver Nanoparticle Clusters (pages 766–770)

      Dong Hwan Wang, Keum Hwan Park, Jung Hwa Seo, Jason Seifter, Ji Hye Jeon, Jung Kyu Kim, Jong Hyeok Park, O Ok Park and Alan J. Heeger

      Version of Record online: 22 AUG 2011 | DOI: 10.1002/aenm.201100347

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      The use of size-controlled Ag nanoparticles (NPs) synthesized by a polyol process in the BHJ shows improved values of Jsc, FF, and the EQE. These results are due to an enhanced light absorption caused by the plasmonic field effect of Ag cluster from NPs and improved charge transport in the active layer. Ag clusters reduce the series resistance and induce an efficient charge transport system in the BHJ active layer.

    8. Spin-Coated Small Molecules for High Performance Solar Cells (pages 771–775)

      Yongsheng Liu, Xiangjian Wan, Fei Wang, Jiaoyan Zhou, Guankui Long, Jianguo Tian, Jingbi You, Yang Yang and Yongsheng Chen

      Version of Record online: 28 JUN 2011 | DOI: 10.1002/aenm.201100230

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      Conjugated small molecules can show excellent performance in bulk heterojunction solar cells. Using a simple solution spinning process, high power conversion efficiencies have been achieved by employing these molecules. As an example, DCAO7T/PC61BM based solar cells exhibit power conversion efficiency values of up to 5.08%, with a short- circuit current density of 10.74 mA/cm2, an open-circuit voltage of 0.86 V, and a fill factor of 55.0%.

    9. Open-Cage Fullerenes as n-Type Materials in Organic Photovoltaics: Relevance of Frontier Energy Levels, Carrier Mobility and Morphology of Different Sizable Open-Cage Fullerenes with Power Conversion Efficiency in Devices (pages 776–780)

      Chih-Ping Chen, Yu-Wei Lin, Jia-Cherng Horng and Shih-Ching Chuang

      Version of Record online: 4 AUG 2011 | DOI: 10.1002/aenm.201100172

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      Organic bulk heterojunction (OBHJ) photovoltaics, incorporating open-cage fullerenes with orifice-size of 8, 12, 13, 16 and 20-membered-rings as n-type materials, display power conversion efficiency (PCE) up to 2.9% by the 8-membered-ring fullerene under AM 1.5G irradiation; their PCEs decrease as the orifice-size of open-cage fullerene increases, primarily due to electron-mobility descends as the cage is ruptured to larger holes.

    10. PEDOT Nanotube Arrays as High Performing Counter Electrodes for Dye Sensitized Solar Cells. Study of the Interactions Among Electrolytes and Counter Electrodes (pages 781–784)

      Roberto Trevisan, Markus Döbbelin, Pablo P. Boix, Eva M. Barea, Ramón Tena-Zaera, Iván Mora-Seró and Juan Bisquert

      Version of Record online: 10 AUG 2011 | DOI: 10.1002/aenm.201100324

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      PEDOT nanotube arrays present a better catalytic activity with I/I3 redox than standard platinized counter electrodes used for dye sensitized solar cells exhibiting thereby a photoconversion efficiency as high as 8.3%. The PEDOT layer introduces an additional series resistance which is compensated by its excellent catalytic performance yielding counter electrodes as good as platinized ones, or even better.

    11. Electronically Monodisperse Single-Walled Carbon Nanotube Thin Films as Transparent Conducting Anodes in Organic Photovoltaic Devices (pages 785–791)

      Timothy P. Tyler, Ryan E. Brock, Hunter J. Karmel, Tobin J. Marks and Mark C. Hersam

      Version of Record online: 16 SEP 2011 | DOI: 10.1002/aenm.201100274

      Thumbnail image of graphical abstract

      Single-walled carbon nanotubes (SWNTs) sorted by electronic type are employed as organic photovoltaic device anodes. Metal-enriched SWNT films yield device efficiencies that are fifty times greater than their semiconducting counterparts. Through sheet resistance, UV-vis-NIR optical absorbance, and X-ray photoelectron spectroscopy measurements, the OPV charge blocking layer PEDOT:PSS is found to reverse the original chemical doping of the SWNT films. The relative insensitivity of metallic SWNTs to chemical doping thus explains the improved performance of metal-enriched SWNT films as OPV anodes.

    12. Spontaneous Charge Transfer and Dipole Formation at the Interface Between P3HT and PCBM (pages 792–797)

      Harri Aarnio, Parisa Sehati, Slawomir Braun, Mathias Nyman, Michel P. de Jong, Mats Fahlman and Ronald Österbacka

      Version of Record online: 17 JUN 2011 | DOI: 10.1002/aenm.201100074

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      Spontaneous formation of dipoles at the P3HT:PCBM interface after annealing is proposed based on UV photoelectron spectroscopy data, the integer charge transfer model and photoinduced absorption data. The interfacial dipoles create an extra barrier for (non-)geminate recombination at the interfaces and thus can explain the reduced recombination and high efficiency observed in annealed regioregular-P3HT:PCBM solar cells.

    13. Template-Free Synthesis of Interconnected Hollow Carbon Nanospheres for High-Performance Anode Material in Lithium-Ion Batteries (pages 798–801)

      Fu-Dong Han, Yu-Jun Bai, Rui Liu, Bin Yao, Yong-Xin Qi, Ning Lun and Jian-Xin Zhang

      Version of Record online: 19 AUG 2011 | DOI: 10.1002/aenm.201100340

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      Interconnected hollow carbon nanospheres (HCNSs) were prepared by pressure-assisted reduction and graphitization of sucrose in autoclaves without template. The obtained HCNSs with a large surface area, very thin graphitic shells, and an interconnected structure exhibit excellent performances as the electrode material for lithium ion batteries.

  6. Full Papers

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Communications
    7. Full Papers
    8. Frontispiece
    9. Full Papers
    1. Optical Properties of Organic Semiconductor Blends with Near-Infrared Quantum-Dot Sensitizers for Light Harvesting Applications (pages 802–812)

      Grigorios Itskos, Andreas Othonos, Tobias Rauch, Sandro F. Tedde, Oliver Hayden, Maksym V. Kovalenko, Wolfgang Heiss and Stelios A. Choulis

      Version of Record online: 16 JUN 2011 | DOI: 10.1002/aenm.201100182

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      Conjugated polymer (P3HT)/fullerene (PCBM) blends sensitized by near-infrared quantum dots (PbS QDs) are investigated by optical spectroscopy. Pristine, binary and ternary blends of the materials with a systematic variation of the QDs to P3HT/PCBM ratio are studied by absorption, photoluminescence and pump-probe absorption. The study discusses charge transfer processes in ternary blends of organic semiconductors with near-infrared QDs for solution-processed photodetectors and photovoltaics.

    2. Enhanced Efficiency in Plastic Solar Cells via Energy Matched Solution Processed NiOx Interlayers (pages 813–820)

      K. Xerxes Steirer, Paul F. Ndione, N. Edwin Widjonarko, Matthew T. Lloyd, Jens Meyer, Erin L. Ratcliff, Antoine Kahn, Neal R. Armstrong, Calvin J. Curtis, David S. Ginley, Joseph J. Berry and Dana C. Olson

      Version of Record online: 18 JUL 2011 | DOI: 10.1002/aenm.201100234

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      Enhanced efficiency and stability of a high performance organic solar cell is demonstrated when the hole collecting indium-tin oxide contact is modified with solution-processed nickel oxide and the high work-function contact is matched with the donor ionization potential. We use photoemission spectroscopy to characterize the band edge positions in the contact layer, a multilayer matrix optical model and a diode model to explain the improvements in contact quality in comparison to the hole-transport layer, polyethylene dioxythiophene:polystyrene sulfonate.

    3. Spinel-Layered Core-Shell Cathode Materials for Li-Ion Batteries (pages 821–828)

      Yonghyun Cho, Sanghan Lee, Yongseok Lee, Taeeun Hong and Jaephil Cho

      Version of Record online: 19 JUL 2011 | DOI: 10.1002/aenm.201100239

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      A high-energy Li[Ni0.54Co0.12Mn0.34]O2 cathode material with two heterostructures, consisting of a layered core phase and a spinel shell phase, was developed using a PVP-functionalized coating of a Mn precursor on Li[Ni0.7Co0.15Mn0.15]O2. This material demonstrates a reversible capacity of 200 mA h g−1 and an excellent cycling and rate capability at 60 °C. Most importantly, this material with two heterostructures demonstrates substantially reduced heat generation compared to Li[Ni0.5Co0.2Mn0.3]O2.

      Corrected by:

      Correction: Correction: Spinel-Layered Core-Shell Cathode Materials for Li-Ion Batteries

      Vol. 1, Issue 6, 986, Version of Record online: 15 NOV 2011

    4. Nanowire-Based Three-Dimensional Transparent Conducting Oxide Electrodes for Extremely Fast Charge Collection (pages 829–835)

      Jun Hong Noh, Hyun Soo Han, Sangwook Lee, Jin Young Kim, Kug Sun Hong, Gil-Sang Han, Hyunjung Shin and Hyun Suk Jung

      Version of Record online: 19 JUL 2011 | DOI: 10.1002/aenm.201100241

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      Core-shell nanowire array photoelectrodes composed of an ITO core and a TiO2 shell are prepared using a vapor transport method and TiCl4 treatments. Dye-sensitized solar cells fabricated using the core-shell nanowires exhibit extremely fast charge collection. The charge-collection time does not increase with increasing electrode thickness, implying that the thickness of solar cells can be increased without losing charge-collection efficiency.

    5. Electrical and Photo-Induced Degradation of ZnO Layers in Organic Photovoltaics (pages 836–843)

      Assaf Manor, Eugene A. Katz, Thomas Tromholt and Frederik C. Krebs

      Version of Record online: 23 AUG 2011 | DOI: 10.1002/aenm.201100227

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      Reversible degradation of VOC and FF of inverted organic solar cells is demonstrated in experiments with concentrated sunlight and by forward biasing in the dark. The degradation could be prevented by simple electrical treatment and even fresh cells can be improved by the same process. The cell degradation and restoration are attributed to generation and degeneration of shunts in ZnO layer.

  7. Frontispiece

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Communications
    7. Full Papers
    8. Frontispiece
    9. Full Papers
    1. Defects in Chalcopyrite Semiconductors: Defects in Cu(In,Ga)Se2 Chalcopyrite Semiconductors: A Comparative Study of Material Properties, Defect States, and Photovoltaic Performance (Adv. Energy Mater. 5/2011) (page 844)

      Qing Cao, Oki Gunawan, Matthew Copel, Kathleen B. Reuter, S. Jay Chey, Vaughn R. Deline and David B. Mitzi

      Version of Record online: 16 SEP 2011 | DOI: 10.1002/aenm.201190024

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      David Mitzi and co-workers have studied defects in Cu(In,Ga)Se2 (CIGS), intentionally induced with controlled processing, with both material and device characterization techniques on p. 845. Structural defects indentified are directly correlated with defect levels extracted from admittance spectroscopy and device behaviors. Reduction of such defects leads to significant improvement of the device photovoltaic performance.

  8. Full Papers

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Communications
    7. Full Papers
    8. Frontispiece
    9. Full Papers
    1. Defects in Cu(In,Ga)Se2 Chalcopyrite Semiconductors: A Comparative Study of Material Properties, Defect States, and Photovoltaic Performance (pages 845–853)

      Qing Cao, Oki Gunawan, Matthew Copel, Kathleen B. Reuter, S. Jay Chey, Vaughn R. Deline and David B. Mitzi

      Version of Record online: 19 AUG 2011 | DOI: 10.1002/aenm.201100344

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      Defects in Cu(In,Ga)Se2 (CIGS), intentionally induced with controlled processing, are studied with both material and device characterization techniques. Structural defects indentified are directly correlated with defect levels extracted from admittance spectroscopy and device behaviors. Reduction of such defects leads to significant improvement of device photovoltaic performance.

    2. Effects of Side Chains on Thiazolothiazole-Based Copolymer Semiconductors for High Performance Solar Cells (pages 854–860)

      Selvam Subramaniyan, Hao Xin, Felix Sunjoo Kim, Safa Shoaee, James R. Durrant and Samson A. Jenekhe

      Version of Record online: 14 JUN 2011 | DOI: 10.1002/aenm.201100215

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      New copolymer semiconductors, based on thiazolothiazole and dithienosilole moieties (PSOTT, PSEHTT and PSOxTT), were synthesized and used to demonstrate effects of side chains on the performance of solar cells. Solar cells under one sun illumination showed an average power conversion efficiency of 2.1% (PSOxTT), 4.1% (PSOTT) and 5.0% (PSEHTT), demonstrating the dramatic effects of the type and topology of side chains.

    3. Perylene Sensitization of Fullerenes for Improved Performance in Organic Photovoltaics (pages 861–869)

      Holger C. Hesse, Jonas Weickert, Christian Hundschell, Xinliang Feng, Klaus Müllen, Bert Nickel, Attila J. Mozer and Lukas Schmidt-Mende

      Version of Record online: 14 JUN 2011 | DOI: 10.1002/aenm.201100211

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      The concept of dye sensitization of fullerenes is presented for organic photovoltaic devices. Enhanced light harvesting, current generation and power conversion efficiency are shown for sensitized solar cells using different donor materials, namely a discotic small molecule hexa-peri-hexabenzocoronene (HBC) and a near-IR absorbing donor polymer poly-cyclopenta-dithiophene-benzothiodiazole (PCPDTBT).

    4. Morphological Characterization of a Low-Bandgap Crystalline Polymer:PCBM Bulk Heterojunction Solar Cells (pages 870–878)

      Haiyun Lu, Bulent Akgun and Thomas P. Russell

      Version of Record online: 1 JUL 2011 | DOI: 10.1002/aenm.201100128

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      A detailed description of morphology is presented for blend films of a low-bandgap silole-containing conjugated polymer, poly[(4,4′bis(2-ethylhexyl)dithieno[3,2-b;2′ 3′-d]silole)-2,6-diyl-alt-(4,7-bis(2-thienyl)-2,1,3-benzothiadiazole)-5,5′-diyl] (PSBTBT) with [6,6]phenyl-C61-butyric acid methyl ester (PCBM). Versatile techniques were used to characterize the morphology of the “As-Spun”, “Pre-Annealed”, and “Post-Annealed” thin films, mimicking the real solar cell devices, and to provide insight into the performance of these mixtures in actual devices.

    5. Improving Microstructured TiO2 Photoanodes for Dye Sensitized Solar Cells by Simple Surface Treatment (pages 879–887)

      Saquib Ahmed, Aurelien Du Pasquier, Tewodros Asefa and Dunbar P. Birnie III

      Version of Record online: 26 JUL 2011 | DOI: 10.1002/aenm.201100121

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      Surface treatments are applied to photoanodes made of sub-micrometer-sized TiO2 nanocrystallite aggregates of high surface area and roughness, for DSSC application. Pre-treatment of the fluorine-doped tin oxide (FTO) layer creates a thin underlayer of TiO2, reducing recombination and improving contact with the FTO. Post-treatment creates a thin over-layer of amorphous TiO2, which increases surface roughness for higher dye adsorption, enhances light-scattering and reduces recombination.

    6. Simple, Highly Efficient Vacuum-Processed Bulk Heterojunction Solar Cells Based on Merocyanine Dyes (pages 888–893)

      Vera Steinmann, Nils M. Kronenberg, Martin R. Lenze, Steven M. Graf, Dirk Hertel, Klaus Meerholz, Hannah Bürckstümmer, Elena V. Tulyakova and Frank Würthner

      Version of Record online: 22 AUG 2011 | DOI: 10.1002/aenm.201100283

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      A simple, highly efficient, vacuum- processed small molecule solar cell based on merocyanine dyes – traditional colorants that can easily be mass-produced and purified – is presented. In the past, merocyanines have been successfully introduced in solution-processed as well as vacuum-processed devices, demonstrating efficiencies up to 4.9%. Here, further optimization of devices is achieved while keeping the same simple layer stack, ultimately leading to efficiencies beyond the 6% mark. In addition, physical properties such as the charge carrier transport and the cell performance under various light intensities are addressed.

    7. Single Nanostructure Electrochemical Devices for Studying Electronic Properties and Structural Changes in Lithiated Si Nanowires (pages 894–900)

      Matthew T. McDowell and Yi Cui

      Version of Record online: 19 JUL 2011 | DOI: 10.1002/aenm.201100258

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      A single-nanostructure electrochemical device framework is developed for testing the electrical properties of single Li battery nanostructures at different lithiation states and correlating these properties with structural changes via TEM. The electrical conductivity of single Si nanowires is found to vary by two to three orders of magnitude between lithiation and delithiation.

    8. Manganese Oxide/Carbon Aerogel Composite: an Outstanding Supercapacitor Electrode Material (pages 901–907)

      Yu-Hsun Lin, Te-Yu Wei, Hsing-Chi Chien and Shih-Yuan Lu

      Version of Record online: 18 JUL 2011 | DOI: 10.1002/aenm.201100256

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      Porous Mn3O4/carbon aerogel composite electrodes prepared with a self-limiting anodic-electrochemical process, show outstanding capacitive properties and high energy and power densities because of the much-enhanced utilization of the functional Mn3O4 deposited as thin nanofibers along the backbone of the highly porous and conductive carbon aerogel matrix.

    9. TiO2 Nanocrystals Synthesized by Laser Pyrolysis for the Up-Scaling of Efficient Solid-State Dye-Sensitized Solar Cells (pages 908–916)

      Hussein Melhem, Pardis Simon, Layla Beouch, Fabrice Goubard, Mourad Boucharef, Catherine Di Bin, Yann Leconte, Bernard Ratier, Nathalie Herlin-Boime and Johann Bouclé

      Version of Record online: 4 AUG 2011 | DOI: 10.1002/aenm.201100289

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      Efficient solid-state dye-sensitized solar cells are processed from porous TiO2 photoanodes based on nanocrystals synthesized by laser pyrolysis. The strategy, which is compatible with production up-scale, allows a fine control of the nanocrystal physical properties. In comparison with commercial benchmark materials, the proposed photoanodes are found to greatly favor pore infiltration by the solid-state molecular glass, leading to improved device performance.

    10. Graphene–Cellulose Paper Flexible Supercapacitors (pages 917–922)

      Zhe Weng, Yang Su, Da-Wei Wang, Feng Li, Jinhong Du and Hui-Ming Cheng

      Version of Record online: 10 AUG 2011 | DOI: 10.1002/aenm.201100312

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      Graphene–cellulose paper (GCP) membrane materials fabricated by simple vacuum filtration are used as electrodes for flexible supercapacitors. The unique three-dimensional interwoven structure of graphene nanosheets and cellulose fibers equips the GCP with excellent mechanical flexibility, high rate capability and capacitance per geometric area of 81 mF cm−2, and long cycling stability. GCP-based flexible polymer supercapacitors with various architectures are demonstrated.

    11. Intra-Molecular Donor–Acceptor Interaction Effects on Charge Dissociation, Charge Transport, and Charge Collection in Bulk-Heterojunction Organic Solar Cells (pages 923–929)

      Huidong Zang, Yongye Liang, Luping Yu and Bin Hu

      Version of Record online: 10 AUG 2011 | DOI: 10.1002/aenm.201100304

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      Intra-molecular donor-acceptor interaction in photovoltaic polymers enhances inter-molecular donor-acceptor interaction in bulk-heterojunction solar cells, leading to an increase in charge dissociation, transport, and collection

    12. Electrode Considerations for the Optical Enhancement of Organic Bulk Heterojunction Solar Cells (pages 930–935)

      Afshin Hadipour, David Cheyns, Paul Heremans and Barry P. Rand

      Version of Record online: 4 AUG 2011 | DOI: 10.1002/aenm.201100250

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      The optical enhancement in conventional and inverted bulk heterojunction organic solar cells is systematically studied with respect to the anode and cathode buffer layers (BL). By removing parasitic absorption caused by low work function metals such as calcium, the photocurrent is increased by 25% leading to an improved efficiency of 3.9% for structures without calcium as a BL compared to reference cell performance of 3.2% using calcium as an electron accepting BL. Furthermore, the impact of the optical properties of transition metal oxides on device performance is assessed.

    13. Vanadium Oxide Nanowire–Carbon Nanotube Binder-Free Flexible Electrodes for Supercapacitors (pages 936–945)

      Sanjaya D. Perera, Bijal Patel, Nour Nijem, Katy Roodenko, Oliver Seitz, John P. Ferraris, Yves J. Chabal and Kenneth J. Balkus Jr.

      Version of Record online: 16 SEP 2011 | DOI: 10.1002/aenm.201100221

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      Binder-free flexible V2O5 nanowire (VNW)/carbon nanotube (CNT) composite paper electrodes are prepared for coin cell type (CR2032) supercapacitors. These composite paper electrodes show a highly porous VNW-CNT network that facilitates Li+ ion and electron diffusion, resulting in high power and energy performance. Additionally, Li+ ions are introduced to the VNWs during the synthesis, which further enhances the power (8.32 kW kg−1) and energy (65.9 Wh Kg−1) densities with improved cycling stability.

    14. Non-Fullerene Acceptor-Based Bulk Heterojunction Polymer Solar Cells: Engineering the Nanomorphology via Processing Additives (pages 946–953)

      Guoqiang Ren, Eilaf Ahmed and Samson A. Jenekhe

      Version of Record online: 17 AUG 2011 | DOI: 10.1002/aenm.201100285

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      The power conversion efficiency of bulk heterojunction polymer solar cells based on a non-fullerene acceptor is enhanced 10-fold from 0.14 to 1.5% by using a processing additive in conjunction with an electron-blocking and a hole-blocking buffer layers. The morphology and device performance vary significantly with the concentration of the processing additive, reaching an optimum at 0.2 vol%, which is far lower than 2-3 vol% found in polymer/fullerene systems.

    15. Morphology-Dependent Trap Formation in High Performance Polymer Bulk Heterojunction Solar Cells (pages 954–962)

      Zach M. Beiley, Eric T. Hoke, Rodrigo Noriega, Javier Dacuña, George F. Burkhard, Jonathan A. Bartelt, Alberto Salleo, Michael F. Toney and Michael D. McGehee

      Version of Record online: 28 JUN 2011 | DOI: 10.1002/aenm.201100204

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      High efficiency bulk heterojunction solar cells based on a relatively recent polymer exhibit morphology and device physics that are very different from those of more commonly studied polymers. Though the polymer has achieved efficiencies exceeding 7%, its performance is limited by a distribution of hole-traps, which are related to the polymer morphology.

    16. Photo-Carrier Recombination in Polymer Solar Cells Based on P3HT and Silole-Based Copolymer (pages 963–969)

      Song Chen, Kaushik Roy Choudhury, Jegadesan Subbiah, Chad M. Amb, John R. Reynolds and Franky So

      Version of Record online: 1 SEP 2011 | DOI: 10.1002/aenm.201100300

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      Bimolecular recombination in polymer solar cells was studied using different polymer: fullerene systems. Compared to regioregular poly(3-hexylthiophene) (P3HT), donor-acceptor polymer solar cells experience significant recombination loss at open circuit condition due to a higher degree of energetic disorder. Photo-induced carrier extraction with linear increasing voltage (Ph-CELIV) and transient photo-voltage (TPV) were carried out for the studies.

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