同時に光制御可能な局所化されたスピンを持つ分子光伝導体
Toshio Naito1, Tomoaki Karasudani, Shigeki Mori
1Graduate School of Science and Engineering, Ehime University, Matsuyama, Japan. tnaito@ehime-u.ac.jp
Journal of the American Chemical Society
|September 6, 2012
まとめ
紫外線は,可逆光化学反応を誘発することで,隔離結晶を磁導体に変えます. このプロセスは,光流と局所的なスピンを生成し,材料の特性に対する光学的な制御を示します.
科学分野:
- マテリアルサイエンス 材料科学
- 固体物理 固体物理学
- フォトケミストリー フォトケミストリー
背景:
- 分子結晶は,調節可能な電子特性を提供しています.
- 材料の伝導性と磁性を制御することは,重要な研究分野です.
- 光化学反応は,物質の状態に大きな変化を誘導することができます.
研究 の 目的:
- 分子結晶の電子性および磁性特性の光誘導による可逆的なスイッチングを調査する.
- 非磁気断熱器から磁気導体への変換の背後にあるメカニズムを探求する.
- 光伝導性と光磁性における電荷移転変数の役割を理解する.
主な方法:
- BPY[Ni ((dmit) (((2))) 分子結晶の合成と特徴付け.
- 特性変化を誘導し観察するためのUV照射実験.
- 導電性の変化を定量化するための光電流測定.
- 電子スピン共振 (ESR) スペクトロスコピーは,局所化されたスピンを検出します.
主要な成果:
- 紫外線照射は,非磁性で絶縁性の高いBPY[Ni(dmit) (((2)) ] ((2)) の結晶を磁導体に逆転的に変換する.
- 伝導率の有意な増加 (1桁の大きさ) と局所的なスピンの生成は,紫外線の下で観察されました.
- 観測された現象は,光化学的リドックス反応と電荷移転変異に起因する.
- この材料は,イオン塩と電荷移転複合体の状態を切り替える可逆光学制御を備えています.
結論:
- BPY[Ni (((dmit) (((2))) は,絶縁状態と磁気伝導状態の間の可逆光スイッチングを示す新しい材料です.
- 光伝導性と光磁性は,紫外線誘発の電荷移転と再酸化反応によって引き起こされます.
- この研究は,分子材料の電子的および磁的性質を光学的に制御するための経路を示しています.
さらに関連する動画
09:00Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
Published on: June 28, 2018
12:51A 'Plug and Play' Method to Create Water-dispersible Nanoassemblies Containing an Amphiphilic Polymer, Organic Dyes and Upconverting Nanoparticles
Published on: November 14, 2015
関連する概念動画
03:02Colors and Magnetism
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
01:23Photoluminescence: Fluorescence and Phosphorescence
Photoluminescence is a process where a molecule absorbs light energy and re-emits it in the form of light. This phenomenon occurs when a substance absorbs photons, promoting its electrons to higher energy level excited states, followed by a relaxation process in which the electrons return to their original ground state energy levels and emit light. Photoluminescence is widely observed in various materials, including semiconductors, and organic and inorganic compounds.
A pair of electrons in a...
A pair of electrons in a...
01:26Photochemical 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
01:29The Photochemical Reaction Center
Reaction centers are pigment-protein complexes that initiate energy conversion from photons to chemical entities. Therefore, photochemical reaction center is a more appropriate term that describes these complexes. The Nobel laureates Robert Emerson and William Arnold provided the first experimental evidence of photochemical reaction centers by demonstrating the participation of nearly 2,500 chlorophyll molecules for the release of just one molecule of oxygen. Despite thousands of photosynthetic...
02:42Valence Bond Theory
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
01:14Photoluminescence: Applications
Photoluminescence offers a wide range of applications due to its inherent sensitivity and selectivity. This technique allows for both direct and indirect analyses of the analyte. Direct quantitative analysis is possible when the analyte exhibits a favorable quantum yield for fluorescence or phosphorescence. However, an indirect analysis may be feasible if the analyte is not fluorescent or phosphorescent, or if the quantum yield is unfavorable. Indirect methods include reacting the analyte with...