Advanced Materials

Cover image for Vol. 24 Issue 32

August 22, 2012

Volume 24, Issue 32

Pages 4345–4462

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Back Cover
    5. Masthead
    6. Contents
    7. Review
    8. Communications
    1. Nanosieves: Use of a Columnar Metal Thin Film as a Nanosieve with Sub-10 nm Pores (Adv. Mater. 32/2012) (page 4345)

      Dong-Hoon Choi, Yong Duk Han, Byung-Kee Lee, Seon-Jin Choi, Hyun C. Yoon, Dae-Sik Lee and Jun-Bo Yoon

      Article first published online: 13 AUG 2012 | DOI: 10.1002/adma.201290193

      Thumbnail image of graphical abstract

      On page 4408, J.-B. Yoon, D.-S. Lee, and co-workers report the first use of a columnar thin film as a nanosieve. The image illustrates a columnar-structured nanosieve (nanoporous membrane) prepared by physical vapor deposition (PVD). Since a thin film formed by PVD has vertically-grown columnar grains, the film naturally has numerous straight-opened nanopores. The generally sputtered film can separate molecules of different sizes.

  2. Inside Front Cover

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Back Cover
    5. Masthead
    6. Contents
    7. Review
    8. Communications
    1. Hybrid Solar Cells: Crafting Semiconductor Organic−Inorganic Nanocomposites via Placing Conjugated Polymers in Intimate Contact with Nanocrystals for Hybrid Solar Cells (Adv. Mater. 32/2012) (page 4346)

      Lei Zhao and Zhiqun Lin

      Article first published online: 13 AUG 2012 | DOI: 10.1002/adma.201290194

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      Semiconductor organic–inorganic nanocom-posites crafted by placing conjugated polymers in intimate contact with nanocrystals markedly promote the dispersion of nanocrystals within the conjugated polymer matrix and facilitate the photoinduced charge transfer between them. On page 4353, Z. Lin and L. Zhao review recent developments in conjugated polymer–nanocrystal nanocomposites, focusing on viable preparative strategies for these semiconductor nanocompos-ites and their photovoltaic performance in hybrid solar cells.

  3. Back Cover

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Back Cover
    5. Masthead
    6. Contents
    7. Review
    8. Communications
    1. Semiconductors: Ambipolar Organic Single-Crystal Transistors Based on Ion Gels (Adv. Mater. 32/2012) (page 4463)

      Yohei Yomogida, Jiang Pu, Hidekazu Shimotani, Shimpei Ono, Shu Hotta, Yoshihiro Iwasa and Taishi Takenobu

      Article first published online: 13 AUG 2012 | DOI: 10.1002/adma.201290195

      Thumbnail image of graphical abstract

      Organic single-crystal electric double transistors (EDLTs) are formed on molecularly flat ion-gel films. On page 4392, T. Takenobu and co-workers report the first realization of ambipolar electric-double-layer transistors (EDLTs) using organic single-crystal and ion-gel electrolytes thorough the fabrication of molecularly flat gel films and the application of novel device architecture to prevent electrochemically unstable calcium electrode from redox reaction. The ambipolar EDLT enables investigation of the HOMO-LUMO-gap energy of semiconductors from transistor characteristics.

  4. Masthead

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Back Cover
    5. Masthead
    6. Contents
    7. Review
    8. Communications
    1. Masthead: (Adv. Mater. 32/2012)

      Article first published online: 13 AUG 2012 | DOI: 10.1002/adma.201290196

  5. Contents

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Back Cover
    5. Masthead
    6. Contents
    7. Review
    8. Communications
    1. Contents: (Adv. Mater. 32/2012) (pages 4347–4352)

      Article first published online: 13 AUG 2012 | DOI: 10.1002/adma.201290192

  6. Review

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Back Cover
    5. Masthead
    6. Contents
    7. Review
    8. Communications
    1. Crafting Semiconductor Organic−Inorganic Nanocomposites via Placing Conjugated Polymers in Intimate Contact with Nanocrystals for Hybrid Solar Cells (pages 4353–4368)

      Lei Zhao and Zhiqun Lin

      Article first published online: 3 JUL 2012 | DOI: 10.1002/adma.201201196

      Thumbnail image of graphical abstract

      Intimately linked semiconductor conjugated polymer−nanocrystal (CP−NC) nanocomposites have received great attention as they possess a well-defined interface that markedly promotes the NC dispersion and facilitates the photoinduced charge transfer for use low-cost, high-efficiency hybrid solar cells. Several viable synthetic strategies have been exploited to craft a large number of such organic−inorganic nanocomposites composed of intimately contacted CPs and inorganic NCs of different types and dimensions.

  7. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Back Cover
    5. Masthead
    6. Contents
    7. Review
    8. Communications
    1. Temperature and Chemical Bonding-Directed Self-Assembly of Cobalt Phosphide Nanowires in Reaction Solutions into Vertical and Horizontal Alignments (pages 4369–4375)

      Shuang-Yuan Zhang, Enyi Ye, Shuhua Liu, Suo Hon Lim, Si Yin Tee, Zhili Dong and Ming-Yong Han

      Article first published online: 16 JUL 2012 | DOI: 10.1002/adma.201201618

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      The preparation of vertically or horizontally aligned self-assemblies of CoP nanowires is demonstrated for the first time by aging them in the reaction solution for a sufficient time at 20 or 0 °C. This strategy opens up a way for exploring the controlled self-assembly of various highly anisotropic nanostructures into long-range ordered structures with collective properties.

    2. High Directivity Optical Antenna Substrates for Surface Enhanced Raman Scattering (pages 4376–4380)

      Dongxing Wang, Wenqi Zhu, Yizhuo Chu and Kenneth B. Crozier

      Article first published online: 3 JUL 2012 | DOI: 10.1002/adma.201201625

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      A two-dimensional array of gold optical antennas integrated with a one-dimensional array of gold strips and mirrors is introduced and fabricated. The experimental results show that this design achieves average surface-enhanced Raman scattering (SERS) enhancement factors as high as 1.2 × 1010, which is more than two orders of magnitude larger than optical antennas without the gold strips and gold mirror.

    3. A New Approach for Probing the Mobility and Lifetime of Photogenerated Charge Carriers in Organic Solar Cells Under Real Operating Conditions (pages 4381–4386)

      A. Baumann, J. Lorrmann, D. Rauh, C. Deibel and V. Dyakonov

      Article first published online: 3 JUL 2012 | DOI: 10.1002/adma.201200874

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      A new transient charge extraction technique is presented, which facilitates simultaneous measurements of mobility and lifetime of photogenerated charge carriers in organic solar cells under real operating conditions. An adaptive field control is implemented keeping the solar cell at open circuit conditions during recombination. The practical benefit of the new technique is demonstrated by determining the mobility-lifetime parameter of solar cells based on PCDTBT:PC71BM and P3HT:PC61BM.

    4. Magnetic Properties of Crystalline and Amorphous Phase-Change Materials Doped with 3d Impurities (pages 4387–4391)

      Wei Zhang, Ider Ronneberger, Yan Li and Riccardo Mazzarello

      Article first published online: 2 JUL 2012 | DOI: 10.1002/adma.201201507

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      First-principles study of the structural and magnetic properties of cubic and amorphous phase-change materials doped with 3d impurities. We find that Co- and Ni-doped Ge2Sb2Te5 is non-magnetic, whereas Cr- and Mn-doped Ge2Sb2Te5 is magnetic and exhibits a significant magnetic contrast between the two phases in the ferromagnetic configuration. These results are explained in terms of differences in local structure and hybridization of the impurity d-orbitals with the host states.

    5. Ambipolar Organic Single-Crystal Transistors Based on Ion Gels (pages 4392–4397)

      Yohei Yomogida, Jiang Pu, Hidekazu Shimotani, Shimpei Ono, Shu Hotta, Yoshihiro Iwasa and Taishi Takenobu

      Article first published online: 22 JUN 2012 | DOI: 10.1002/adma.201200655

      Thumbnail image of graphical abstract

      Ambipolar electric double-layer transistors (EDLTs) using organic single crystals and ion-gel electrolytes are successfully created by optimising the fabrication of gel films. The p- and n-type EDLTs enable us to investigate the HOMO-LUMO gap energy of semiconductors, offering a new method with which to measure it.

    6. Toward Robust Nanogenerators Using Aluminum Substrate (pages 4398–4402)

      Sangmin Lee, Jung-Il Hong, Chen Xu, Minbaek Lee, Dongseob Kim, Long Lin, Woonbong Hwang and Zhong Lin Wang

      Article first published online: 2 JUL 2012 | DOI: 10.1002/adma.201201525

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      Nanogenerators (NG) have been developed to harvest mechanical energy from environmental sources such as vibration, human motion, or movement of automobiles. We demonstrate a robust and large-area NG based on a cost-effective Al substrate with the capability to be easily integrated in series and parallel for high-output performance. The output voltage and current density of the three-dimensionally integrated NG device reaches up to 3 V and 195 nA under human walking conditions.

    7. Polarity Switching of Charge Transport and Thermoelectricity in Self-Assembled Monolayer Devices (pages 4403–4407)

      David A. Egger, Ferdinand Rissner, Egbert Zojer and Georg Heimel

      Article first published online: 16 JUL 2012 | DOI: 10.1002/adma.201200872

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      Self-assembled monolayer devices can exhibit drastically different charge-transport characteristics and thermoelectric properties despite being composed of isomeric molecules with essentially identical frontier-orbital energies. This is rationalized by the cooperative electrostatic action of local intramolecular dipoles in otherwise nonpolar species, thus revealing new challenges but also new opportunities for the targeted design of functional building blocks in future nanoelectronics.

    8. Use of a Columnar Metal Thin Film as a Nanosieve with Sub-10 nm Pores (pages 4408–4413)

      Dong-Hoon Choi, Yong Duk Han, Byung-Kee Lee, Seon-Jin Choi, Hyun C. Yoon, Dae-Sik Lee and Jun-Bo Yoon

      Article first published online: 22 JUN 2012 | DOI: 10.1002/adma.201200755

      Thumbnail image of graphical abstract

      A columnar-structured nanosieve is unique in the sense that it is a general thin film formed by physical vapor deposition (PVD). Instead of additional processes to make nanopores, the numerous voids naturally formed among columnar grains during PVD are used as nanopores. Since the thin film formed by PVD has vertically grown columnar grains, the fabricated nanosieve has numerous straight-opened nanopores, which is an ideal structure for a nanosieve.

    9. Langmuir–Schaeffer Monolayers of Colloidal Nanocrystals for Cost-Efficient Quantum Dot Light-Emitting Diodes (pages 4414–4418)

      Hélène Bourvon, Stéphanie Le Calvez, Hani Kanaan, Sylvia Meunier-Della-Gatta, Cécile Philippot and Peter Reiss

      Article first published online: 16 JUL 2012 | DOI: 10.1002/adma.201200981

      Thumbnail image of graphical abstract

      Quantum dot (QD) LEDs of high color purity, and low turn-on voltage and leakage current are prepared using a solvent free method. First, a monolayer of QDs is formed at the air/water interface, which is then transferred with a PDMS stamp onto the device. The method is applicable to large substrates and reduces materials consumption as compared to other deposition techniques.

    10. Functional Nanoporous Graphene Foams with Controlled Pore Sizes (pages 4419–4423)

      Xiaodan Huang, Kun Qian, Jie Yang, Jun Zhang, Li Li, Chengzhong Yu and Dongyuan Zhao

      Article first published online: 12 JUL 2012 | DOI: 10.1002/adma.201201680

      Thumbnail image of graphical abstract

      A simple hydrophobic-affinity-derived assembly approach to pack graphene sheets into a nanoporous foam structure has been developed. Nanoporous graphene foams with the highest pore volume and large surface area are obtained. The pore diameter of the graphene foams can be finely adjusted from the mesopore to the macropore range by employing spherical templates with different sizes.

    11. Nematic Director-Induced Switching of Assemblies of Hexagonally Packed Gold Nanorods (pages 4424–4429)

      Michael R. Thomas, Susanne Klein, Robert J. Greasty, Stephen Mann, Adam W. Perriman and Robert M. Richardson

      Article first published online: 3 JUL 2012 | DOI: 10.1002/adma.201201319

      Thumbnail image of graphical abstract

      Self-assembled disc-shaped clusters of hexagonally packed, thiol-functionalized gold nanorods are prepared and dispersed in thermotropic nematic liquid crystals. The resultant hybrid complex fluids exhibit colloidal anisotropy with very high orientational order and are characterized by SAXS as shown in the figure. Precise, reconfigurable control of the cluster orientation at very low electric field strengths (0.18 V μm−1) is achieved.

    12. Ionic Liquid-Nanoparticle Hybrid Electrolytes and their Application in Secondary Lithium-Metal Batteries (pages 4430–4435)

      Yingying Lu, Shyamal K. Das, Surya S. Moganty and Lynden A. Archer

      Article first published online: 12 JUL 2012 | DOI: 10.1002/adma.201201953

      Thumbnail image of graphical abstract

      Ionic liquid-tethered nanoparticle hybrid electrolytes comprised of silica nanoparticles densely grafted with imidazolium-based ionic liquid chains are shown to retard lithium dendrite growth in rechargeable batteries with metallic lithium anodes. The electrolytes are demonstrated in full cell studies using both high-energy Li/MoS2 and high-power Li/TiO2 secondary batteries.

    13. Polymer-Free Near-Infrared Photovoltaics with Single Chirality (6,5) Semiconducting Carbon Nanotube Active Layers (pages 4436–4439)

      Rishabh M. Jain, Rachel Howden, Kevin Tvrdy, Steven Shimizu, Andrew J. Hilmer, Thomas P. McNicholas, Karen K. Gleason and Michael S. Strano

      Article first published online: 28 JUN 2012 | DOI: 10.1002/adma.201202088

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      We demonstrate a polymer-free carbon-based photovoltaic device that relies on exciton dissociation at the SWNT/C60 interface, as shown in the figure. Through the construction of a carbon-based photovoltaic completely free of polymeric active or transport layers, we show both the feasibility of this novel device as well as inform the mechanisms for inefficiencies in SWNTs and carbon based solar cells.

    14. Strong Phonon Scattering by Layer Structured PbSnS2 in PbTe Based Thermoelectric Materials (pages 4440–4444)

      Jiaqing He, Steven N. Girard, Jin-Cheng Zheng, Lidong Zhao, Mercouri G. Kanatzidis and Vinayak P. Dravid

      Article first published online: 18 JUL 2012 | DOI: 10.1002/adma.201201565

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      The incorporation of PbSnS2 in PbTe results in a tremendous reduction of the lattice thermal conductivity to 0.8 W/mK at room temperature, a reduction of almost 60% over bulk PbTe. Transmission electron microscopy reveals very high density displacement layers, misfit dislocations, and phase boundaries. Our thermal transport calculations based on modified Debye-Callaway model, well in agreement with the experimental measurements, reveal that the layer structured PbSnS2 plays an important role in reducing the lattice thermal conductivity.

    15. Stable Solution-Processed Molecular n-Channel Organic Field-Effect Transistors (pages 4445–4450)

      Do Kyung Hwang, Raghunath R. Dasari, Mathieu Fenoll, Valérie Alain-Rizzo, Amir Dindar, Jae Won Shim, Nabankur Deb, Canek Fuentes-Hernandez, Stephen Barlow, David G. Bucknall, Pierre Audebert, Seth R. Marder and Bernard Kippelen

      Article first published online: 12 JUL 2012 | DOI: 10.1002/adma.201201689

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      A new solution-processable small-molecule containing electron-poor naphthalene diimide and tetrazine moieties has been synthesized. The optimized spin-coated n-channel OFETs on glass substrate shows electron mobility value up to 0.15 cm2 V−1 s−1. Inkjet-printed OFETs are fabricated in ambient atmosphere on flexible plastic substrates, which exhibits an electron mobility value up to 0.17 cm2 V−1 s−1and also shows excellent environmental and operational stability.

    16. Mesoporous CuO Particles Threaded with CNTs for High-Performance Lithium-Ion Battery Anodes (pages 4451–4456)

      Sungwook Ko, Jung-In Lee, Hee Seung Yang, Soojin Park and Unyong Jeong

      Article first published online: 12 JUL 2012 | DOI: 10.1002/adma.201201821

      Thumbnail image of graphical abstract

      Mesoporous CuO particles threaded with carbon nanotubes are suggested as a novel class of nanocomposite material for a high-performance anode in the lithium-ion batteries. The nanocomposite electrode exhibits a highly reversible capacity (650 mA h g−1 at 0.1 C rate) and an excellent C rate capability (580 mA h g−1 at 5 C, and 500 mA h g−1 at 10 C).

    17. “Cut and Stick” Rubbery Ion Gels as High Capacitance Gate Dielectrics (pages 4457–4462)

      Keun Hyung Lee, Moon Sung Kang, Sipei Zhang, Yuanyan Gu, Timothy P. Lodge and C. Daniel Frisbie

      Article first published online: 3 JUL 2012 | DOI: 10.1002/adma.201200950

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      A free-standing polymer electrolyte called an ion gel is employed in both organic and inorganic thin-film transistors as a high capacitance gate dielectric. To prepare a transistor, the free-standing ion gel is simply laid over a semiconductor channel and a side-gate electrode, which is possible because of the gel's high mechanical strength.

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