Advanced Functional Materials

Cover image for Vol. 12 Issue 10

October, 2002

Volume 12, Issue 10

Pages 647–734

    1. Contents: Adv. Funct. Mater. 10/2002 (pages 647–649)

      Article first published online: 21 OCT 2002 | DOI: 10.1002/1616-3028(20021016)12:10<647::AID-ADFM647>3.0.CO;2-J

    2. Articles in Upcoming Issues (page 650)

      Article first published online: 21 OCT 2002 | DOI: 10.1002/1616-3028(20021016)12:10<650::AID-ADFM650>3.0.CO;2-6

    3. Organization of Matter on Different Size Scales: Monodisperse Nanocrystals and Their Superstructures (pages 653–664)

      A.L. Rogach, D.V. Talapin, E.V. Shevchenko, A. Kornowski, M. Haase and H. Weller

      Article first published online: 21 OCT 2002 | DOI: 10.1002/1616-3028(20021016)12:10<653::AID-ADFM653>3.0.CO;2-V

      Advances in colloidal syntheses, enabling the preparation of semiconductors and magnetic alloy nanocrystals with narrow size distributions and specific surface functionalities, are described. Such nanocrystals can be used for fabrication of two- and three-dimensional arrays and colloidal supercrystals (see Figure) by simple chemical techniques (see also inside front cover). Also, a theoretical description of the control over nanocrystal monodispersity is presented.

    4. In-Situ Compositional and Structural Analysis of Plastic Solar Cells (pages 665–669)

      J.K.J. van Duren, J. Loos, F. Morrissey, C.M. Leewis, K.P.H. Kivits, L.J. van IJzendoorn, M.T. Rispens, J.C. Hummelen and R.A.J. Janssen

      Article first published online: 21 OCT 2002 | DOI: 10.1002/1616-3028(20021016)12:10<665::AID-ADFM665>3.0.CO;2-J

      In-situ structural and compositional analysis of as-prepared opto-electronic polymer devices has been carried out by TEM and cryogenic Rutherford backscattering spectrometry (RBS). For solar cells based on poly(1,4-phenylenevinylene) (PPV)-C60 derivatives, diffusion of electrode materials (Al and In) into the polymer layers is minor, and spontaneous stratification of the two components does not occur as can be seen from the cover.

    5. Reversible Polarization Gratings on Thin Films of Polyoxetanes Bearing 4-(N,N-Diphenyl)amino-4′-nitroazobenzene Chromophores (pages 670–678)

      S.W. Cha, D.H. Choi, D.K. Oh, D.Y. Han, C.E. Lee and J.-I. Jin

      Article first published online: 21 OCT 2002 | DOI: 10.1002/1616-3028(20021016)12:10<670::AID-ADFM670>3.0.CO;2-Z

      The formation of polarization gratings in thin films of a series of azobenzene-containing polyoxetanes (such as the one shown in the Figure) is examined. It is demonstrated that both the mode of attachment of the chromophore to the main chain (end-on vs. side-on) and the length of the side-chain spacer influence the dynamic properties of the diffraction gratings.

    6. Synthesis and Characterization of Crystalline Ag2Se Nanowires Through a Template-Engaged Reaction at Room Temperature (pages 679–686)

      B. Gates, B. Mayers, Y. Wu, Y. Sun, B. Cattle, P. Yang and Y. Xia

      Article first published online: 21 OCT 2002 | DOI: 10.1002/1616-3028(20021016)12:10<679::AID-ADFM679>3.0.CO;2-#

      Single-crystalline Ag2Se nanowires (see Figure for a TEM image) were synthesized by a template-engaged, topotactic reaction using trigonal selenium nanowires as template. The highly uniform Ag2Se nanowires are candidates for photosensitizers, superionic conductors, and magnetoresistive or thermoelectric materials. This work is the first example of a template-engaged process generating single-crystalline nanowires from solution and at RT.

    7. Controlling Steps During Early Stages of the Aligned Growth of Carbon Nanotubes Using Microwave Plasma Enhanced Chemical Vapor Deposition (pages 687–692)

      L.C. Chen, C.Y. Wen, C.H. Liang, W.K. Hong, K.J. Chen, H.C. Cheng, C.S. Shen, C.T. Wu and K.H. Chen

      Article first published online: 21 OCT 2002 | DOI: 10.1002/1616-3028(20021016)12:10<687::AID-ADFM687>3.0.CO;2-3

      Vertical alignment of carbon nanotubes (CNTs) with control over length and diameter (see Figure) can be induced during the microwave-plasma-enhanced chemical vapor deposition of these nanotubes. Parameters leading to alignment and the influence of nitrogen addition during the deposition process are discussed. Formation of high-density fine carbon onion encapsulated metal particles is observed under hydrogen plasma treatment.

    8. Fluorine Segregation Controls the Solid-State Organization and Electronic Properties of Ni and Au Dithiolene Complexes: Stabilization of a Conducting Single-Component Gold Dithiolene Complex (pages 693–698)

      O.J. Dautel, M. Fourmigué, E. Canadell and P. Auban-Senzier

      Article first published online: 21 OCT 2002 | DOI: 10.1002/1616-3028(20021016)12:10<693::AID-ADFM693>3.0.CO;2-F

      A recurrent layered structure with fluorous bilayers is observed in neutral nickel and gold dithiolene complexes. [Au(F2pdt)2]· is a semiconductor with high room-temperature conductivity. The origin of this semiconducting behavior as well as possible guidelines in order to realize metallic conductivity in gold dithiolene neutral molecular solids are discussed.

    9. Cyano-Substituted Oligothiophenes: A New Approach to n-Type Organic Semiconductors (pages 699–708)

      A. Yassar, F. Demanze, A. Jaafari, M. El Idrissi and C. Coupry

      Article first published online: 21 OCT 2002 | DOI: 10.1002/1616-3028(20021016)12:10<699::AID-ADFM699>3.0.CO;2-S

      A general synthesis of conductive α,ω-dicyano-oligothiophenes with three to six thiophene rings (see Figure) and of substituted cyano-terthiophenes has been developed using Pd-catalyzed coupling of organotin- or halozinc-substituted thiophenes with thienyl halides. By virtue of its electron acceptor substituents, α,ω-dicyano-sexithiophene shows the typical current–voltage characteristics of an n-type semiconductor.

    10. A Low-Bandgap Semiconducting Polymer for Photovoltaic Devices and Infrared Emitting Diodes (pages 709–712)

      C.J. Brabec, C. Winder, N.S. Sariciftci, J.C. Hummelen, A. Dhanabalan, P.A. van Hal and R.A.J. Janssen

      Article first published online: 21 OCT 2002 | DOI: 10.1002/1616-3028(20021016)12:10<709::AID-ADFM709>3.0.CO;2-N

      Conjugated polymers with a bandgap < 2 eV are promising for optoelectronic devices. Implementation of the new copolymer PTPTB (see Figure) into bulk heterojunction solar cell devices and light-emitting diodes, as well as the sensitization of electroluminescence by energy transfer from a wide bandgap polymer, are demonstrated.

    11. (Pb1–xCdx)S Nanoparticles Embedded in a Conjugated Organic Matrix, as Studied by Photoluminescence and Light-Induced X-ray Photoelectron Spectroscopy (pages 713–718)

      R. Buller, H. Cohen, E. Minkin, R. Popovitz-Biro, E. Lifshitz and M. Lahav

      Article first published online: 21 OCT 2002 | DOI: 10.1002/1616-3028(20021016)12:10<713::AID-ADFM713>3.0.CO;2-6

      Elliptically shaped (Pb1–xCdx)S nanoparticles (NPs) of average size 2.3 × 2.9 nm in diameter have been prepared in a solid oligo(p-phenylene-ethynylene)dicarboxylate organic matrix. These particles, smaller than corresponding pure PbS and CdS, show significantly longer emission lifetime. Light-induced X-ray photoelectron spectroscopy has been applied, for the first time, for structural characterization of the NPs.

    12. Arrays of Ordered Pb Nanowires and Their Optical Properties for Laminated Polarizers (pages 719–722)

      Y.-T. Pang, G.-W. Meng, L.-D. Zhang, Y. Qin, X.-Y. Gao, A.-W. Zhao and Q. Fang

      Article first published online: 21 OCT 2002 | DOI: 10.1002/1616-3028(20021016)12:10<719::AID-ADFM719>3.0.CO;2-J

      A laminated micropolarizer of Pb nanowire arrays has been fabricated within an anodic alumina membrane (AAM) by anodization of the pure Al foil and subsequent electrodeposition of Pb. Spectrophotometry measurements show that the Pb nanowire arrays embedded in AAM (see Figure) can only transmit polarized light vertical to the wires, which renders them suitable for wire grid type micropolarizers.

    13. Synthesis and Properties of a Series of Regioregularly Amino-Substituted Oligo- and Polythiophenes (pages 723–728)

      G. Götz, S. Scheib, R. Klose, J. Heinze and P. Bäuerle

      Article first published online: 21 OCT 2002 | DOI: 10.1002/1616-3028(20021016)12:10<723::AID-ADFM723>3.0.CO;2-2

      A homologous series of donor-substituted oligothiophenes (see Figure), bearing pyrrolidino groups in the “outer” β-positions, have been synthesized. Due to the substitution pattern, even the longer oligomers form films well and could be electropolymerized to the corresponding polythiophenes.

    14. Correlation Between Molecular Structure, Microscopic Morphology, and Optical Propertiesof Poly(tetraalkylindenofluorene)s (pages 729–733)

      A.C. Grimsdale, P. Leclère, R. Lazzaroni, J.D. MacKenzie, C. Murphy, S. Setayesh, C. Silva, R.H. Friend and K. Müllen

      Article first published online: 21 OCT 2002 | DOI: 10.1002/1616-3028(20021016)12:10<729::AID-ADFM729>3.0.CO;2-F

      The emission properties and film morphologies of polyindenofluorenes with various proportions of straight- and branched-chain alkyl substituents have been compared. A clear correlation is established between the degree of straight-chain alkyl substitution on the polymers, the formation of ordered structures in their films, and the amount of long wavelength emission in the solid-state spectra.

    15. Correction: Adv. Funct. Mater. 2002, 12, 203. (page 734)

      Article first published online: 21 OCT 2002 | DOI: 10.1002/1616-3028(20021016)12:10<734::AID-ADFM734>3.0.CO;2-V