Study of the coherent states in two-dimensional dye aggregates

二维染料聚集体相干态的研究

• 批准号: 04452086
• 负责人: MIYANO Kenjiro
• 金额: $ 4.22万
• 依托单位: University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1993
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04452086/
• 关键词: two-dimensional Dye aggregate; Frenkel excitons; disorder; localization; dimensionality; superradiance; 二次元色素集合系; J会合体; H会合体; エキシトン; 蛍光寿命; ポンプ・プローブ法; コヒーレント状態; 双極子相互作用; 四光波混合; 非線形光学

The purpose of this study was to gain the molecular picture of the two-dimensional excitonic states in dye aggregates. For this purpose, we have performed the following experiments :(1) We established the preparation techniques for J- and H-aggregates. For the former, adsorption from solution produced most desirable results whereas, for the latter, Langmuir-Blodgett technique worked best. (2) We made a cryostat equipped with a microscope which enabled us to do spectroscopy from 0.02 mm diameter area in a monolayr. (3) We performed absorption and emission spectroscopy from liquid He temperature to room temperature. (4) We studied harmonic generation from H-aggregate. (5) The fluorescence lifetime was measured with a streak camera. (6) A preliminary study was done using a pump-and-probe method.Our findings are as follows :(1) The spectroscopic data can be perfectly described by the Frenkel exciton picture modified with the static disorder and phonons. (2) The dimensionality does not appear qualitatively in the optical properties. (3) The fluorescence lifetime is extremely fast, which seems to be the manifestation of the large number of coherently excited molecules, a qualitative signature of two-dimensionality. (4) The local-field approximation well describes the second-harmonic generation process in H-aggregate, i.e.the coherency does not affect the harmonic generation.

本研究的目的是获得染料聚集体中二维激子态的分子图像。为此，我们进行了以下实验：(1)建立了J-聚集体和H-聚集体的制备工艺。对于前者，从溶液中吸附产生最理想的结果，而对于后者，Langmuir-Blodgett技术效果最好。(2)制作了一台配有显微镜的低温恒温器，使我们能够在一个单层的直径为0.02 mm的区域内进行光谱测量。(3)测量了从液态氦到室温的吸收光谱和发射光谱。(4)研究了H-聚集体的谐波产生。(5)用条纹相机测量荧光寿命。(6)利用泵浦和探测的方法进行了初步的研究，我们的结果如下：(1)用静态无序和声子修正的Frenkel激子图可以很好地描述光谱数据。(2)在光学性质上没有定性地表现出维度。(3)荧光寿命极快，这似乎是大量相干激发分子的表现，这是二维的定性特征。(4)局域场近似很好地描述了H聚集体中二次谐波的产生过程，即相干性不影响二次谐波的产生。

项目成果

H.Ui,A.Tomioka,T.Nishiwaki,and K.Miyano: "Local-Field Effects in the Second-Harmonic Generation from Langmuir-Blodgett Monolayers." J.Chem.Phys.101. 6430-6438 (1994)

H.Ui、A.Tomioka、T.Nishiwaki 和 K.Miyano：“Langmuir-Blodgett 单层膜二次谐波产生中的局域场效应”。

M.Kuwata-Gonokami,N.Peyghambarian,et al.: "Exciton Strings in an Organic Charge-transfer Crystal" Nature. 367. 47-48 (1994)

M.Kuwata-Gonokami、N.Peyghambarian 等人：“有机电荷转移晶体中的激子串”自然。

G.Xu,K.Okuyama,M.Shimomura: "Crystal Structure of H-Aggregate of Azobenzene-containing Amphiphiles,C6AzoC8NBr and C8AzoC10NBr" Mol.Cryst.Liq.Cryst.213. 105-115 (1992)

G.Xu，K.Okuyama，M.Shimomura：“含偶氮苯的两亲物，C6AzoC8NBr 和 C8AzoC10NBr 的 H 聚集体的晶体结构”Mol.Cryst.Liq.Cryst.213。

M.Kuwata-Gonokami,et al.: "Exciton Strings in an Organic Charge-Transfer Crystal" Nature. 367. 47-48 (1994)

M.Kuwata-Gonokami 等人：“有机电荷转移晶体中的激子串”自然。

K.Hosoi, T.Ishikawa, A.Tomioka, K.Miyano: "Quantitative Image Analysis in Brewster Angle Microscopy : Molecular Tilt of a Stearic Acid Monolayr on Water" Jpn.J.Appl.Phys.32. L135-L137 (1993)

K.Hosoi、T.Ishikawa、A.Tomioka、K.Miyano：“布儒斯特角显微镜中的定量图像分析：水中硬脂酸单层的分子倾斜”Jpn.J.Appl.Phys.32。