光学波長における3次元周期性を持つ炭素構造
1A. A. Zakhidov and I. Khayrullin are at AlliedSignal, Incorporated, Research and Technology, Morristown, NJ 07962-1021, USA, and in the Department of Thermal Physics of the Uzbekistan Academy of Sciences, Katartal 28, Tashkent, Uzbekistan. R. H. Baugh.
Science (New York, N.Y.)
|October 30, 1998
まとめ
研究者らは,天然のオパール構造を模倣した新種の多孔性炭素を作り出した. これらの材料は光子結晶の性質を示し,高度な光学アプリケーションの可能性を秘めています.
科学分野:
- マテリアルサイエンス 材料科学
- ナノテクノロジー ナノテクノロジー
- オプティクスは光学です.
背景:
- 周期的構造を持つ有孔炭素は,光子学的応用において極めて重要です.
- 自然なオパール形成を複製することは,新しい合成経路を提供します.
研究 の 目的:
- オパルテンプレート法を使用して3次元周期性多孔性炭素を合成する.
- 結果となる炭素逆オパルの構造的多様性と光学的性質を調査する.
主な方法:
- 毛細なシリカオパール結晶の合成.
- シリカオパルをシンタリングして,インタースフィアのインターフェースを作成します.
- 炭素前駆体による浸透と,その後のシリカ除去.
- 結果となる炭素逆オパルの特徴.
主要な成果:
- 異なる構造を持つ多孔性炭素逆オパールを成功して合成した.
- ダイヤモンドとガラスのような炭素の逆オパルは,ボリュームフィリングで得られます.
- 表面テンプレートを介してタイルされたグラファイトシートでグラファイトの逆オパールを生産した.
- 炭素逆オパールで介電と金属の両方の光学特性を実証しました.
結論:
- オパルのテンプレートメソッドは,多彩な多孔性炭素構造の作成に有効です.
- 合成された炭素逆オパールは,光学フォトニック結晶として機能します.
- これらの材料は,光子バンドギャップ材料の開発に希望を示しています.
関連する概念動画
02:22Structures of Solids
Solids in which the atoms, ions, or molecules are arranged in a definite repeating pattern are known as crystalline solids. Metals and ionic compounds typically form ordered, crystalline solids. A crystalline solid has a precise melting temperature because each atom or molecule of the same type is held in place with the same forces or energy. Amorphous solids or non-crystalline solids (or, sometimes, glasses) which lack an ordered internal structure and are randomly arranged. Substances that...
02:18X-ray Crystallography
The size of the unit cell and the arrangement of atoms in a crystal may be determined from measurements of the diffraction of X-rays by the crystal, termed X-ray crystallography.
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
01:16UV–Vis Spectroscopy: Molecular Electronic Transitions
In Ultraviolet–Visible (UV–Vis) spectroscopy, the absorption of electromagnetic radiation is used to probe the electronic structure of molecules. This technique provides insights into molecular electronic transitions, particularly the movement of electrons between different molecular orbitals. Radiation is absorbed if the energy of the electromagnetic radiation passing through the molecule is precisely equal to the energy difference between the excited and ground states. During this process,...
01:24The Seven Crystal Systems: Overview
Crystals with various point group symmetries belong to different crystal classes, which are synonymous terms. Despite being in the same class, crystals may have distinct shapes, like cubes and octahedra. There are 32 three-dimensional point groups, all of which are systematically divided into seven crystal systems.The basic cubic crystal system, exemplified by NaCl, features orthogonal vectors (α = β = �� = 90°) of equal lengths (a = b = c). When specific requirements are not imposed on the...
01:29Determination of Crystal Structures
In the late 1800s, the revelation that light extended beyond visible wavelengths led to the discovery of X-rays by Wilhelm Roentgen. Recognized as high-energy electromagnetic radiation with short wavelengths, X-rays prompted exploration into their interaction with crystals. Max von Laue proposed in 1912 that the periodic arrangement of atoms, ions, or molecules in crystals would cause them to diffract X-rays, a hypothesis confirmed through experiments with copper sulfate and zinc sulfide...