RESEARCH ON THE PRIMARY PROCESSES OF PHOTO-CONDUCTION IN AROMATIC VINYL POLYMERS BY MEANS OF FEMTOSECOND DICHROISM MEASUREMENT AND NEAR LASER SPECTROSCOPY.

飞秒二色性测量和近激光光谱研究芳香族乙烯基聚合物光传导的初级过程。

• 批准号: 14340183
• 负责人: MIYASAKA Hiroshi
• 金额: $ 9.47万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14340183/
• 关键词: PICOSECOND LASER SPECTROSCOPY; FEMTSECOND LASER SPECTROSCOPY; ELECTRON TRANSFER; PHOTOCONDUCTIVE POLYMER; CARRIER GENERATION; CARRIER TRANSPORT; 電子移動; 光電導体; 近赤外分光; ホール移動

The transport of electrons initiated by photoexcitation is ubiquitous in nature as well as in artificial systems. Photoconductivity in aromatic vinyl polymers is one of the typical phenomena closely related to these fundamental processes. Since the band structures in the electronic states are not plausible because of rather small interaction among the pendant aromatic groups, hopping model has been proposed for this carrier transport processes. Still unclear are the factors regulating the charge shift reaction between two neighboring aromatic groups in a molecular level. To obtain deeper insights into this efficient electron transfer reaction, photoinduced electron transfer dynamics (charge separation, charge recombination and hole transfer reactions) in poly (N-vinylcarbazole) (PVCz) and solvent effects on the reaction profiles were studied by means of picosecond and femtosecond transient absorption spectroscopy and transient dichroism measurements.Electron transfer dynamics in PVCz in rather polar solutions was well described by the simple scheme that the cation state of carbazolyl (Cz+) moiety continuously migrates along pendant Cz moieties in the polymer chain with the charge recombination at the initial position of the charge separation. The dichroism measurement in femtosecond -a few picosecond time region revealed that the delocalization of the cationic state over Cz units takes an important role for the subsequent hole transfer. That is, the delocalization leads to the decrease in the effective inter-ionic distance to reduce the Coulombic attractive energy in the initial pair and also the decrease in the reorganization energy in the electron transfer reaction accelerates the hole transfer process.

由光激发引发的电子输运在自然界和人工系统中普遍存在。芳香族乙烯基聚合物的光电导是与这些基本过程密切相关的典型现象之一。由于电子态的能带结构是不合理的，因为相当小的相互作用的侧芳基，跳跃模型已被提出的载流子输运过程。在分子水平上调控两个相邻芳香基团之间电荷转移反应的因素尚不清楚。为了更深入地了解这种有效的电子转移反应，（电荷分离，电荷复合和空穴转移反应（N-乙烯基咔唑）（PVCz）利用皮秒和飞秒瞬态吸收光谱和瞬态二向色性测量研究了PVCz和溶剂效应对反应曲线的影响，并利用瞬态二向色性测量很好地描述了PVCz在较强极性溶液中的电子转移动力学。简单的方案，咔唑基（Cz+）部分的阳离子状态连续迁移沿着侧链Cz部分在聚合物链与电荷复合的电荷分离的初始位置。飞秒-几皮秒时间范围内的二向色性测量表明，Cz单元上阳离子态的离域对随后的空穴传输起着重要作用。也就是说，离域导致有效离子间距离的减小以降低初始对中的库仑吸引能，并且电子转移反应中重组能的减小加速空穴转移过程。

项目成果

Hiroshi Miyasaka: "Solvent effect of the hole migration along a poly(N-vinylcarbazole) chain as revealed by picosecond transient absorption and dichroism measurements"J. Phys. Chem.. A106(10). 2192-2199 (2002)

Hiroshi Miyasaka：“皮秒瞬态吸收和二色性测量揭示了空穴沿着聚（N-乙烯基咔唑）链迁移的溶剂效应”J。

宮坂 博: "ピコ秒・フェムト秒時間分解分光で見る高分子系の電子移動反応"高分子. 51[12]. 959 (2002)

Hiroshi Miyasaka：“通过皮秒/飞秒时间分辨光谱观察聚合物系统中的电子转移反应”Polymers 51[12]。

S.R.Khan: "Picosecond electron transfer dynamics in polymer systems in solutions : cellulose tris(9-ethylcarbazolyl-3-carbamate) and amylose tris(9-ethylcarbazolyl-3-carbamate)"J.Photochem.Photobio.A.. 161,1. 35-42 (2003)

S.R.Khan：“溶液中聚合物系统中的皮秒电子转移动力学：纤维素三（9-乙基咔唑基-3-氨基甲酸酯）和直链淀粉三（9-乙基咔唑基-3-氨基甲酸酯）”J.Photochem.Photobio.A.. 161,1

H.Matsuda: "Development of kinetic analysis system in pump-probe measurement based on femtosecond chromium : forsterite laser and its application to S_1-S_0 relaxation dynamics of azulene"J.Photochem.Photobio.A.. 156,1-3. 69-75 (2003)

H.Matsuda：“基于飞秒铬的泵浦探针测量动力学分析系统的开发：镁橄榄石激光及其在甘菊环S_1-S_0弛豫动力学中的应用”J.Photochem.Photobio.A.. 156,1-3。

Y.Tsuboi: "Nonlinear photophysics and ablation of liquid naphthalene derivatives : fluence-dependence of luminescence spectra upon 248 nm laser excitation"J.Phys.Chem., B.. 107,17. 3017-3023 (2003)

Y.Tsuboi：“非线性光物理学和液体萘衍生物的烧蚀：248 nm 激光激发时发光光谱的注量依赖性”J.Phys.Chem.，B.. 107,17。