Advanced Materials

Cover image for Vol. 13 Issue 6

March, 2001

Volume 13, Issue 6

Pages 369–450

    1. Photonic Crystals (page 369)

      Y. Xia

      Version of Record online: 15 MAR 2001 | DOI: 10.1002/1521-4095(200103)13:6<369::AID-ADMA369>3.0.CO;2-T

      Photonic crystals are the central theme of this issue of Advanced Materials. A glimpse of the diverse range of topics covered in the fourteen articles that comprise this special issue can be obtained by reading the essay by the guest editor Younan Xia on page 369.

    2. Chemical Approaches to Three-Dimensional Semiconductor Photonic Crystals (pages 371–376)

      D. J. Norris and Yu. A. Vlasov

      Version of Record online: 15 MAR 2001 | DOI: 10.1002/1521-4095(200103)13:6<371::AID-ADMA371>3.0.CO;2-K

      Recent efforts to make 3D semiconductor photonic crystals using self-assembly techniques are reviewed. These approaches, which utilize a synthetic opal as a template to shape the semiconductor material (see Figure), provide a simple and inexpensive alternative to lithographic methods.

    3. Silicon-Based Photonic Crystals (pages 377–388)

      A. Birner, R. B. Wehrspohn, U. M. Gösele and K. Busch

      Version of Record online: 15 MAR 2001 | DOI: 10.1002/1521-4095(200103)13:6<377::AID-ADMA377>3.0.CO;2-X

      Photonic crystals can be thought of as optical analogues of semiconductors. Here recent advances in photonic crystals based on silicon are reviewed. After summarizing the theory of photonic bandgap materials, the preparation and linear optical properties of 1D, 2D, and 3D silicon-based photonic crystals are discussed. Laterally structured porous silicon with a defect line is shown in the Figure.

    4. The Fabrication and Bandgap Engineering of Photonic Multilayers (pages 389–393)

      P. Jiang, G. N. Ostojic, R. Narat, D. M. Mittleman and V. L. Colvin

      Version of Record online: 15 MAR 2001 | DOI: 10.1002/1521-4095(200103)13:6<389::AID-ADMA389>3.0.CO;2-L

      New opportunities for engineered photonic behaviorhave been found in the preparation of multilayer colloidal crystals (see Figure). Each layer of the crystal consists of a three-dimensionally ordered array of close-packed colloids. These multilayer samples are amenable to templating methods for tuning the dielectric contrast and mechanical properties of the material.

    5. Synthesis and Photonic Bandgap Characterization of Polymer Inverse Opals (pages 393–396)

      H. Míguez, F. Meseguer, C. López, F. López-Tejeira and J. Sánchez-Dehesa

      Version of Record online: 15 MAR 2001 | DOI: 10.1002/1521-4095(200103)13:6<393::AID-ADMA393>3.0.CO;2-4

      Polymer inverse opals with long-range order (see Figure) have been fabricated and their photonic crystal behavior examined. Good agreement between band structure calculations and experiment is found. It is envisaged that these inverse opals could be used for the modification of the electronic properties of incorporated luminescent materials and as matrices for the synthesis of spherical colloidal particles.

    6. Structured Metallic Films for Optical and Spectroscopic Applications via Colloidal Crystal Templating (pages 396–400)

      P. M. Tessier, O. D. Velev, A. T. Kalambur, A. M. Lenhoff, J. F. Rabolt and E. W. Kaler

      Version of Record online: 15 MAR 2001 | DOI: 10.1002/1521-4095(200103)13:6<396::AID-ADMA396>3.0.CO;2-T

      Two new methods of preparing thin porous metallic films, based on controlled co-crystallization of latex microspheres and gold nanoparticles, have been developed by these authors. The new materials show interesting optical properties and excellent surface-enhanced Raman spectroscopy (SERS) activity. The Figure shows a square pore array obtained at a specific film thickness.

    7. Gems of Chemistry and Physics: Macroporous Metal Oxides with 3D Order (pages 401–407)

      C. F. Blanford, H. Yan, R. C. Schroden, M. Al-Daous and A. Stein

      Version of Record online: 15 MAR 2001 | DOI: 10.1002/1521-4095(200103)13:6<401::AID-ADMA401>3.0.CO;2-7

      Naturally occurring gem opals have inspired the recent explosion of work on 3D ordered macroporous (3DOM) materials (see Figure). This work focuses on ordered metal oxides and the effects that the chemistry behind precursors and template removal have on the phase and composition of the end product. Structural features that affect the materials' photonic, optical, catalytic, and magnetic properties are discussed.

    8. Self-Assembly Approaches to Three-Dimensional Photonic Crystals (pages 409–413)

      Y. Xia, B. Gates and Z.-Y. Li

      Version of Record online: 15 MAR 2001 | DOI: 10.1002/1521-4095(200103)13:6<409::AID-ADMA409>3.0.CO;2-C

      The historical development of photonic bandgap (PBG) materials is outlined here and the fabrication methods employed are discussed with emphasis on self-assembly processes. The factors influencing the generation of a complete bandgap, from both an experimental and a calculational standpoint are then presented and discussed. The Figure shows a diamond-like 3D periodic structure.

    9. Three-Dimensional Photonic Crystals with Non-spherical Colloids as Building Blocks (pages 415–420)

      Y. Lu, Y. Yin and Y. Xia

      Version of Record online: 15 MAR 2001 | DOI: 10.1002/1521-4095(200103)13:6<415::AID-ADMA415>3.0.CO;2-O

      The potential use of non-spherical colloids (see Figure) as building blocks for the self-assembly of 3D photonic crystals with bandgaps located in the optical regime is examined. Methods for producing non-spherical colloids as monodisperse samples and with well-defined shapes and tightly controlled dimensions are presented, and the approaches employed to organize these non-spherical colloids into 3D crystalline lattices are discussed.

    10. Polymer-Based Photonic Crystals (pages 421–425)

      A. C. Edrington, A. M. Urbas, P. DeRege, C. X. Chen, T. M. Swager, N. Hadjichristidis, M. Xenidou, L. J. Fetters, J. D. Joannopoulos, Y. Fink and E. L. Thomas

      Version of Record online: 15 MAR 2001 | DOI: 10.1002/1521-4095(200103)13:6<421::AID-ADMA421>3.0.CO;2-#

      The development of polymers as photonic crystals is highlighted, placing special emphasis on self-assembled block copolymers. 1D self-assembled multilayers as well as 2D and 3D self-assembled structures are examined, then intricate block polymer structures such as that shown in the Figure are discussed as are birefringent multilayer and elastomeric films.

    11. Patterning Porous Oxides within Microchannel Networks (pages 427–431)

      P. Yang, A. H. Rizvi, B. Messer, B. F. Chmelka, G. M. Whitesides and G. D. Stucky

      Version of Record online: 15 MAR 2001 | DOI: 10.1002/1521-4095(200103)13:6<427::AID-ADMA427>3.0.CO;2-C

      Microchannel networks can be used as a confined space for patterning microporous, mesoporous, and macroporous materials of various compositions, as illustrated here. These hierarchically ordered materials (see Figure) hold promise for use as advanced catalysts, sensors, low-k dielectrics, and optoelectronic and integrated photonic crystal devices.

    12. Photonic Bandgaps in Disordered Inverse-Opal Photonic Crystals (pages 433–436)

      Z.-Y. Li and Z.-Q. Zhang

      Version of Record online: 15 MAR 2001 | DOI: 10.1002/1521-4095(200103)13:6<433::AID-ADMA433>3.0.CO;2-O

      Three-dimensional photonic crystals with full bandgaps at optical wavelengths can be fabricated with inverse-opal techniques. It is shown here that the bandgap is extremely sensitive to the presence of geometric disorder in the crystals, with the bandgap closing completely with a disorder strength as small as under two percent of the lattice constant. This fragility persists even at very high refractive index contrasts and is attributed to the creation of a bandgap at high frequency bands (8–9 bands) in inverse-opal crystals.

    13. Synthetic SiO2 Opals (pages 437–441)

      P. Ni, P. Dong, B. Cheng, X. Li and D. Zhang

      Version of Record online: 15 MAR 2001 | DOI: 10.1002/1521-4095(200103)13:6<437::AID-ADMA437>3.0.CO;2-8

      High-quality SiO2 opalscan be obtained by a procedure involving strict selection of the SiO2 spheres. As demonstrated here, monodispersity of the spheres is one of the major factors for obtaining opals with interesting optical properties and large size. The infiltration process of TiO2 into SiO2 opal in order to form inverse opal structures (see Figure) is also discussed.

    14. Inverse Face-Centered Cubic Thin Film Photonic Crystals (pages 443–446)

      G. Subramania, K. Constant, R. Biswas, M. M. Sigalas and K.-M. Ho

      Version of Record online: 15 MAR 2001 | DOI: 10.1002/1521-4095(200103)13:6<443::AID-ADMA443>3.0.CO;2-K

      A technique for fabricating inverse face-centered cubic photonic crystalsfrom a colloidal system of monodisperse microspheres and titania nanoparticles is presented here. Background materials other than titania can also be used if they are available as nanoparticles. The Moiré pattern of a typical photonic crystal sample is shown in the Figure.

    15. Photonic Crystals from Emulsion Templates (pages 447–450)

      V. N. Manoharan, A. Imhof, J. D. Thorne and D. J. Pine

      Version of Record online: 15 MAR 2001 | DOI: 10.1002/1521-4095(200103)13:6<447::AID-ADMA447>3.0.CO;2-4

      Macroporous titaniais obtained by polymerizing a titania sol suspended around “colloidal crystals” of oil droplets. The deformable template counteracts cracking of the titania phase. The Figure shows a scanning electron micrograph of a rutile sample with 200 nm pores, obtained by calcining the titania gel. There is no resultant collapse of the pore structure.