関連する実験動画
Updated: May 14, 2026

07:24
Visible-light Induced Reduction of Graphene Oxide Using Plasmonic Nanoparticle
Published on: September 22, 2015
光刺激グラファンの非常に長い非放射性放緩は酸化によって大きく加速される:時間領域 ab initio研究
Tammie R Nelson1, Oleg V Prezhdo
1Department of Chemistry, University of Rochester, Rochester, New York 14627, United States.
Journal of the American Chemical Society
|February 5, 2013
まとめ
純粋なグラファンは,半導体アプリケーションに理想的な,非常に長寿命の電子刺激を発揮します. 酸化グラファンはより速くエネルギーを失いますが,原始グラファンはエネルギー損失が遅いので,有望な材料です.
科学分野:
- 材料科学 材料科学とは
- 凝縮物質物理学 凝縮物質物理学
- コンピューティング・ケミストリー
背景:
- グラファンおよびその誘導体は,電子およびエネルギーアプリケーションの潜在的な薄い,広帯域のギャップ半導体です.
- 効率的な半導体材料には,長寿命のバンドギャップ刺激と,熱への非放射性エネルギー損失を遅らせる必要があります.
研究 の 目的:
- 純粋なグラファンと酸化グラファンの電子刺激の非放射性寿命と放射性線幅を決定する.
- グラファンベースの材料におけるエネルギー損失メカニズムに影響を与える要因を理解する.
主な方法:
- 最先端の非アディアバティック分子動力学シミュレーション.
- 時間依存密度関数理論 (TD-DFT) の計算.
主要な成果:
- プリスティングラファンは,非常に長い非放射性崩壊時間 (約. 100 ns) でした.
- エポキシおよびヒドロキシグラファンは,純粋なグラファンよりも10〜20倍速く電子刺激エネルギーを失います.
- 純粋なグラファンの非放射性崩壊は,特定の振動モード (1200 cm−1) に結合することによって制御されます.
結論:
- プリスティングラファンのゆっくりとした電子-フォノンエネルギー損失は,半導体アプリケーションの優れた候補となります.
- 酸化グラファンは,より広範な振動モード結合により,より速いエネルギー分散を示します.
- グラファンの誘導体は,高度な材料設計のために調整可能な電子および光学特性を提供します.
関連する概念動画
Atomic Nuclei: Types of Nuclear Relaxation
Nuclear relaxation restores the equilibrium population imbalance and can occur via spin–lattice or spin–spin mechanisms, which are first-order exponential decay processes.
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers energy to a nearby...
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers energy to a nearby...
Deactivation Processes: Jablonski Diagram
Luminescence, the emission of light by a substance that has absorbed energy, is a process that involves the interaction of molecules with light. The energy-level diagram, or Jablonski diagram, is a graphical representation of these interactions, illustrating the various states and transitions a molecule can undergo. In a typical Jablonski diagram, the lowest horizontal line represents the ground-state energy of the molecule, which is usually a singlet state. This state represents the energies...
Photochemical Electrocyclic Reactions: Stereochemistry
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
Oxidative Cleavage of Alkenes: Ozonolysis
In ozonolysis, ozone is used to cleave a carbon–carbon double bond to form aldehydes and ketones, or carboxylic acids, depending on the work-up.
Ozone is a symmetrical bent molecule stabilized by a resonance structure.
Ozone is a symmetrical bent molecule stabilized by a resonance structure.
Cycloaddition Reactions: MO Requirements for Photochemical Activation
Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.
Phase I Reactions: Oxidation of Aliphatic and Aromatic Carbon-Containing Systems
Phase I biotransformation reactions are integral to drug metabolism, predominantly involving oxidative, reductive, and hydrolytic transformations. Chief among these are oxidative reactions, which enhance the hydrophilicity of xenobiotics and introduce polar functional groups to facilitate their elimination from the body.
Oxidation reactions are fundamental in aromatic carbon-containing systems. An example is the hydroxylation of phenobarbital, a process that transforms it into...
Oxidation reactions are fundamental in aromatic carbon-containing systems. An example is the hydroxylation of phenobarbital, a process that transforms it into...

