Advanced Functional Materials

Cover image for Vol. 19 Issue 15

August 10, 2009

Volume 19, Issue 15

Pages 2351–2512

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Full Papers
    6. Frontispiece
    7. Full Papers
    8. Index
    1. Morphology-Tunable Micro/Nanostructures: Characterization, Cathodoluminescence, and Field-Emission Properties of Morphology-Tunable CdS Micro/Nanostructures (Adv. Funct. Mater. 15/2009)

      Tianyou Zhai, Xiaosheng Fang, Yoshio Bando, Benjamin Dierre, Baodan Liu, Haibo Zeng, Xijin Xu, Yang Huang, Xiaoli Yuan, Takashi Sekiguchi and Dmitri Golberg

      Article first published online: 3 AUG 2009 | DOI: 10.1002/adfm.200990065

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      On page 2423, T. Y. Zhai et al. report that high quality and uniform 1D CdS micro/nanostructures with different morphologies can be fabricated through a simple and effective thermal evaporation process. Both cathodoluminescence and field-emission measurements are made and clear correlations between morphology, structure, and optical and field emission performance are established.

  2. Inside Front Cover

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Full Papers
    6. Frontispiece
    7. Full Papers
    8. Index
    1. Supramolecular Self-Assembly: Self-Assembly of a Donor-Acceptor Dyad Across Multiple Length Scales: Functional Architectures for Organic Electronics (Adv. Funct. Mater. 15/2009)

      Jeffrey M. Mativetsky, Marcel Kastler, Rebecca C. Savage, Desirée Gentilini, Matteo Palma, Wojciech Pisula, Klaus Müllen and Paolo Samorì

      Article first published online: 3 AUG 2009 | DOI: 10.1002/adfm.200990066

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      More than the sum of its parts: by covalently coupling polycyclic donor and acceptor moieties, Samori and co-workers demonstrate on page 2486 that a donor–acceptor dyad, based on nanographene and perylene, self-assembles into highly ordered supramolecular architectures with nanosegregated coaxial donor and acceptor regions. The cover image features an atomic force microscopy image of mesoscopic ribbons along with the proposed crystallographic arrangement of the constituent molecules.

  3. Contents

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Full Papers
    6. Frontispiece
    7. Full Papers
    8. Index
    1. Contents: (Adv. Funct. Mater. 15/2009) (pages 2351–2358)

      Article first published online: 3 AUG 2009 | DOI: 10.1002/adfm.200990067

  4. Full Papers

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Full Papers
    6. Frontispiece
    7. Full Papers
    8. Index
    1. Living Yeast Cells as a Controllable Biosynthesizer for Fluorescent Quantum Dots (pages 2359–2364)

      Ran Cui, Hui-Hui Liu, Hai-Yan Xie, Zhi-Ling Zhang, Yi-Ran Yang, Dai-Wen Pang, Zhi-Xiong Xie, Bei-Bei Chen, Bin Hu and Ping Shen

      Article first published online: 12 JUN 2009 | DOI: 10.1002/adfm.200801492

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      An example of how to solve seemingly intractable chemistry problems through biology by a novel strategy of coupling intracellular, unrelated biochemical reactions for controllable synthesis of CdSe QDs using living yeast cells as a biosynthesizer is demonstrated. The CdSe QDs can be tunably synthesized under in vivo conditions and at only 30 °C, instead of at high temperatures around 300 °C and using combustible, explosive, and toxic organic reagents.

    2. Influence of Dielectric Surface Chemistry on the Microstructure and Carrier Mobility of an n-Type Organic Semiconductor (pages 2365–2372)

      Parul Dhagat, Hanna M. Haverinen, R. Joseph Kline, Youngsuk Jung, Daniel A. Fischer, Dean M. DeLongchamp and Ghassan E. Jabbour

      Article first published online: 24 JUN 2009 | DOI: 10.1002/adfm.200900298

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      The effect of self-assembled monolayer treatment on the microstructure of 3,4,9,10-perylenetetracarboxylic bis-benzimidazole (PTCBI) is investigated. Change in the unit cell orientation is observed between bare silicon oxide and octadecyltrichlorosilane (OTS-18) treated substrates. The quality of OTS-18 does not change the microstructure, but it influences the extent of dielectric surface passivation, which plays a critical role in improving charge mobility in PTCBI thin films.

    3. Surface-Modified Mesoporous SiO2 Containers for Corrosion Protection (pages 2373–2379)

      Ekaterina V. Skorb, Dmitri Fix, Daria V. Andreeva, Helmuth Möhwald and Dmitry G. Shchukin

      Article first published online: 8 JUL 2009 | DOI: 10.1002/adfm.200801804

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      Incorporation of containers into special sol–gel matrix causes a self-healing effect during the corrosion process. This is attributed to release of entrapped corrosion inhibitors (2-(benzothiazol-2-ylsulfanyl)- succinic acid) in response to pH changes caused by the corrosion process. The hybrid film with nanocontainers reveals enhanced long-term corrosion protection of aluminum alloy AA2024 in comparison with the individual sol–gel films.

    4. Observation of a 2D Electron Gas and the Tuning of the Electrical Conductance of ZnO Nanowires by Controllable Surface Band-Bending (pages 2380–2387)

      Youfan Hu, Yang Liu, Wenliang Li, Min Gao, Xuelei Liang, Quan Li and Lian-Mao Peng

      Article first published online: 1 JUL 2009 | DOI: 10.1002/adfm.200900179

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      Evidence for of a 2D electron gas and an anomalous temperature dependence in the conductance are presented in devices based on ZnO nanowires (NWs). The phenomena are attributed to the coexistence of the metallic surface shell and semiconducting inner NW core. The nature of the NW surface shell can be tuned reversibly from metallic to insulating by surface band-bending; this reversible switching between high and low conductive states may serve as the basis for a variety of sensing devices.

    5. A New Series of Quadrupolar Type Two-Photon Absorption Chromophores Bearing 11, 12-Dibutoxydibenzo[a,c]-phenazine Bridged Amines; Their Applications in Two-Photon Fluorescence Imaging and Two-Photon Photodynamic Therapy (pages 2388–2397)

      Marappan Velusamy, Jiun-Yi Shen, Jiann T. Lin, Yi-Chih Lin, Cheng-Chih Hsieh, Chin-Hung Lai, Chih-Wei Lai, Mei-Lin Ho, Yu-Chun Chen, Pi-Tai Chou and Jong-Kai Hsiao

      Article first published online: 8 JUL 2009 | DOI: 10.1002/adfm.200900125

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      New quadrupolar type two-photon absorption chromophores bearing an arylamine-dibenzo[a,c]phenazine-arylamine motif exhibit large 2PA cross sections as measured by the two-photon induced fluorescence and Z-scan methods. They are water soluble due to incorporation in silica nanoparticles. The potential applications of these chromophores in two-photon fluorescence imaging and two-photon photodynamic therapy are demonstrated.

    6. Three-Dimensional Bulk Heterojunction Morphology for Achieving High Internal Quantum Efficiency in Polymer Solar Cells (pages 2398–2406)

      Jang Jo, Seok-In Na, Seok-Soon Kim, Tae-Woo Lee, Youngsu Chung, Seok-Ju Kang, Doojin Vak and Dong-Yu Kim

      Article first published online: 8 JUL 2009 | DOI: 10.1002/adfm.200900183

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      3D morphology favorable for electrode function in P3HT:PCBM bulk heterojunction solar cells (see figure) is confirmed by TEM and TOF-SIMS measurements of the composite films before and after optimized solvent-annealing. The efficiency parameters, particularly the internal quantum efficiencies, of the device after solvent-annealing for different times are also compared.

    7. Controlling Electron and Hole Charge Injection in Ambipolar Organic Field-Effect Transistors by Self-Assembled Monolayers (pages 2407–2415)

      Xiaoyang Cheng, Yong-Young Noh, Jianpu Wang, Marta Tello, Johannes Frisch, Ralf-Peter Blum, Antje Vollmer, Jürgen P. Rabe, Norbert Koch and Henning Sirringhaus

      Article first published online: 1 JUL 2009 | DOI: 10.1002/adfm.200900315

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      SAM modification in ambipolar transistors is able to improve both electron and hole injection. The results reported here show that gold electrodes modified by 1DT exhibit improved contact resistance for both electrons and holes compared to O2 plasma-treated gold electrodes. The origin of this unexpected behavior is investigated in terms of SAM-induced change of work-function, film thickness, interfacial tunneling resistance and interfacial electronic and molecular structure.

    8. Effect of Electric Field on Coulomb-Stabilized Excitons in Host/Guest Systems for Deep-Blue Electrophosphorescence (pages 2416–2422)

      Stephan Haneder, Enrico Da Como, Jochen Feldmann, Michael M. Rothmann, Peter Strohriegl, Christian Lennartz, Oliver Molt, Ingo Münster, Christian Schildknecht and Gerhard Wagenblast

      Article first published online: 1 JUL 2009 | DOI: 10.1002/adfm.200900197

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      The effect of electric field on the phosphorescence of type I and II emitting structures for deep-blue OLEDs is investigated. Among the different effects influencing the efficiency of OLEDs based on phosphors, electric field induced quenching of phosphorescence is very sensitive to the emitter-host combination. The design rules for obtaining material combinations capable of reduced quenching are outlined and discussed.

    9. Characterization, Cathodoluminescence, and Field-Emission Properties of Morphology-Tunable CdS Micro/Nanostructures (pages 2423–2430)

      Tianyou Zhai, Xiaosheng Fang, Yoshio Bando, Benjamin Dierre, Baodan Liu, Haibo Zeng, Xijin Xu, Yang Huang, Xiaoli Yuan, Takashi Sekiguchi and Dmitri Golberg

      Article first published online: 22 JUN 2009 | DOI: 10.1002/adfm.200900295

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      High-quality, uniform one-dimensional CdS micro/nanostructures with different morphologies—microrods, sub-microwires and nanotips—are fabricated through an easy and effective thermal evaporation process. Both cathodoluminescence and field-emission measurements are made and clear correlations between morphology, structure, and optical and field emission performances are established.

    10. Pore-Filling of Spiro-OMeTAD in Solid-State Dye Sensitized Solar Cells: Quantification, Mechanism, and Consequences for Device Performance (pages 2431–2436)

      I-Kang Ding, Nicolas Tétreault, Jérémie Brillet, Brian E. Hardin, Eva H. Smith, Samuel J. Rosenthal, Frédéric Sauvage, Michael Grätzel and Michael D. McGehee

      Article first published online: 8 JUL 2009 | DOI: 10.1002/adfm.200900541

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      Pore-filling of spiro-OMeTAD in mesoporous TiO2 films is quantified using UV–vis absorption spectroscopy and XPS depth profiling. The mechanism of pore filling is elucidated in detail and enhancement in pore filling is shown to improve the device efficiency. This finding suggests the importance of pore filling in device performance.

  5. Frontispiece

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Full Papers
    6. Frontispiece
    7. Full Papers
    8. Index
    1. Nanostructure Fracturing: Brittle-to-Ductile Transition in Uniaxial Compression of Silicon Pillars at Room Temperature (Adv. Funct. Mater. 15/2009)

      Fredrik Östlund, Karolina Rzepiejewska-Malyska, Klaus Leifer, Lucas M. Hale, Yuye Tang, Roberto Ballarini, William W. Gerberich and Johann Michler

      Article first published online: 3 AUG 2009 | DOI: 10.1002/adfm.200990068

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      On page 2439, F. Östlund et al. report on an interesting effect observed during the compression of sub-micrometer silicon pillars; a critical diameter separates pillars that are observed to crack from pillars that exhibit metal-like ductility. This observation allows for the development of a quantitative method for measuring the fracture toughness of such structures, which can be used to predict and explain small-volume fracture behavior.

  6. Full Papers

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Full Papers
    6. Frontispiece
    7. Full Papers
    8. Index
    1. Brittle-to-Ductile Transition in Uniaxial Compression of Silicon Pillars at Room Temperature (pages 2439–2444)

      Fredrik Östlund, Karolina Rzepiejewska-Malyska, Klaus Leifer, Lucas M. Hale, Yuye Tang, Roberto Ballarini, William W. Gerberich and Johann Michler

      Article first published online: 18 JUN 2009 | DOI: 10.1002/adfm.200900418

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      A size-related brittle-to-ductile transition in single crystal silicon is underlined by the plastic response seen in the figure. An arrested crack forms in a 400 nm diameter pillar while a slightly smaller 310 nm one only plastically deforms. Size-related fracture toughness values calculated from these pillars are the first quantitative observations of such behavior with in situ crack measurements.

    2. Nanostructured Bulk Silicon as an Effective Thermoelectric Material (pages 2445–2452)

      Sabah K. Bux, Richard G. Blair, Pawan K. Gogna, Hohyun Lee, Gang Chen, Mildred S. Dresselhaus, Richard B. Kaner and Jean-Pierre Fleurial

      Article first published online: 22 JUN 2009 | DOI: 10.1002/adfm.200900250

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      Bulk-scale nanostructured silicon is demonstrated to be a potential high-temperature thermoelectric material with an unprecedented 250% increase in the thermoelectric figure of merit over single-crystal silicon. This is mainly due to a significant reduction in the lattice thermal conductivity with limited degradation in carrier mobility.

    3. Direct Conversion of Single-Layer SnO Nanoplates to Multi-Layer SnO2 Nanoplates with Enhanced Ethanol Sensing Properties (pages 2453–2456)

      Kun-Mu Li, Yi-Jing Li, Ming-Yen Lu, Chung-I Kuo and Lih-Juann Chen

      Article first published online: 8 JUN 2009 | DOI: 10.1002/adfm.200801774

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      Ethanol sensing SnO2 nanoplates (SEM images, a–d) are formed from single-layer SnO nanoplates. In the presence of 50 ppm ethanol, the sensitivity (defined by R0/R, see plot in e) of multi-layer SnO2 nanoplates (pink) are more than double that of single-layer SnO2 nanoplates (purple), which are also formed from the SnO nanoplates. The higher sensitivity is attributed to the larger surface/volume ratio of the multi-layer SnO2 nanoplates compared to that of the single-layer SnO2 nanoplates.

    4. Electron-Rich Alcohol-Soluble Neutral Conjugated Polymers as Highly Efficient Electron-Injecting Materials for Polymer Light-Emitting Diodes (pages 2457–2466)

      Fei Huang, Yong Zhang, Michelle S. Liu and Alex K.-Y. Jen

      Article first published online: 10 JUN 2009 | DOI: 10.1002/adfm.200801898

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      Three kinds of alcohol-soluble neutral conjugated polymers with different conjugation length and electron affinity were designed and synthesized as electron injection materials for polymer light-emitting diodes. It was found that their electron injection abilities are highly influenced by the electron affinity of their main chain and the processing conditions of these polymers.

    5. Periodic TiO2 Nanorod Arrays with Hexagonal Nonclose-Packed Arrangements: Excellent Field Emitters by Parameter Optimization (pages 2467–2473)

      Yue Li, Xiaosheng Fang, Naoto Koshizaki, Takeshi Sasaki, Liang Li, Shuyan Gao, Yoshiki Shimizu, Yoshio Bando and Dmitri Golberg

      Article first published online: 2 JUL 2009 | DOI: 10.1002/adfm.200801857

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      Periodic TiO2 nanorod arrays with hexagonal nonclose-packed arrangements are synthesized. The present method is significantly simpler and of lower cost than lithography-based routes. The parameter-optimized results suggest that arrays with a smaller periodicity and a larger distance between the neighboring nanorods display the best FE performance (see figure) and could be highly valuable for designing field-emission devices.

    6. Thermo-Switchable Charge Transport and Electrocatalysis Using Metal-Ion-Modified pNIPAM-Functionalized Electrodes (pages 2474–2480)

      Michael Riskin, Ran Tel-Vered and Itamar Willner

      Article first published online: 2 JUL 2009 | DOI: 10.1002/adfm.200900268

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      Controllable phase-transition temperature of a thermosensitive polymer can be achieved by the incorporation of metal ions (Ag+, Cu2+, Hg2+). The nature of the ions does not only affect the gel-to-solid phase transition temperature, but the electro-reduced metallic nanoclusters in the polymers also yield matrices with temperature-switchable conductivity and temperature-dependent electrocatalytic behavior.

    7. Photovoltaics Based on Hybridization of Effective Dye-Sensitized Titanium Oxide and Hole-Conductive Polymer P3HT (pages 2481–2485)

      Ke-Jian Jiang, Kazuhiro Manseki, You-Hai Yu, Naruhiko Masaki, Kazuharu Suzuki, Yan-lin Song and Shozo Yanagida

      Article first published online: 8 JUL 2009 | DOI: 10.1002/adfm.200900283

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      Quasi-solid-state TiO2/dye molecule/P3HT solar cells give conversion efficiencies of up to 2.70% under 1 sun illumination. Effective electron injection from the dye molecules and efficient charge transfer from π-stacked P3HT polymers via their self-organized interface result in the respectable performance accompanied by the electronic roles of imidazolium cation, lithium cation, and t-BP as adsorbent to nc-TiO2.

    8. Self-Assembly of a Donor-Acceptor Dyad Across Multiple Length Scales: Functional Architectures for Organic Electronics (pages 2486–2494)

      Jeffrey M. Mativetsky, Marcel Kastler, Rebecca C. Savage, Desirée Gentilini, Matteo Palma, Wojciech Pisula, Klaus Müllen and Paolo Samorì

      Article first published online: 18 JUN 2009 | DOI: 10.1002/adfm.200900366

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      A new dyad incorporating electron donor (D) and acceptor (A) units is synthesized and shown to self-assemble to form highly ordered monolayers, nanofibers, mesoscopic ribbons, and filaments with nanosegregated D and A regions. Ambipolar transport characteristics in a transistor configuration further illustrate the promise of the D-A coupling approach to producing functional supramolecular architectures for solution processable organic electronic applications.

    9. Densely Packed Arrays of Ultra-High-Aspect-Ratio Silicon Nanowires Fabricated using Block-Copolymer Lithography and Metal-Assisted Etching (pages 2495–2500)

      Shih-Wei Chang, Vivian P. Chuang, Steven T. Boles, Caroline A. Ross and Carl V. Thompson

      Article first published online: 21 MAY 2009 | DOI: 10.1002/adfm.200900181

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      Ordered arrays of sub-20-nm, high-aspect-ratio single-crystal silicon nanowires are fabricated using metal-assisted etching in conjunction with block-copolymer lithography and post-etching critical point drying. Wires with a narrow size distribution are created as either continuous carpets or as carpets in topographic features, demonstrating accurate control over wire placement. The wire arrays will have applications in photonic and sensing devices.

    10. Magnetic and Structural Investigation of ZnSe Semiconductor Nanoparticles Doped With Isolated and Core-Concentrated Mn2+ Ions (pages 2501–2510)

      Christina Graf, Andreas Hofmann, Thomas Ackermann, Christine Boeglin, Ranjani Viswanatha, Xiaogong Peng, Arantxa Fraile Rodríguez, Frithjof Nolting and Eckart Rühl

      Article first published online: 30 JUN 2009 | DOI: 10.1002/adfm.200801602

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      X-Ray magnetic circular dichroism experiments are reported on ZnSe nanoparticles containing either single Mn2+ sites distributed over the entire nanoparticle lattice or a MnSe core in the center. The magnetic ions are highly polarized. They are not coupling if the nanoparticles contain isolated manganese ions and show reduced polarization and enhanced Mn–Mn interactions in the core/shell structures.

  7. Index

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

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