Excitonic nonlinearity of regioregular π-conjugated polymer

区域规整π共轭聚合物的激子非线性

• 批准号: 11440099
• 负责人: EMA Kazuhiro
• 金额: $ 8.96万
• 依托单位: Sophia University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B).
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11440099/
• 关键词: polymer; exciton; nonlinear optics; polythiophene; Langmuir-Blodgett (LB) films; low-dimensional material; conjugation length; relaxation mechanism; π共役系高分子; 電子格子相互作用; 4光波混合; 非線形効果; Ag励起状態; コヒーレントフォノン; フォノン; ラマン散乱; フェムト秒パルス; 非線形分光; ポリマー

We investigated excitonic nonlinearity of polythiophene derivative poly(3-[2-((S)-2-methylbutoxy)ethyl]thiophene), which has good regularity in structure. Our study focused two points ; 1) the dependence of excitonic nonlinearity on the effective conjugation length, 2) the relaxation mechnism of exciton. Our research results are following ;1) Third-order optical nonlinearity around excitonic resonance in spincoated films and Langmuir-Blodgett (LB) films of polythiophene derivative, poly(3-[2-((S)-2-methylbutoxy)ethyl]thiophene), is measured using degenerate four wave mixing method. The largest χ^<(3)> value (〜10^<-7> esu) in conjugated polymers is obtained. By a fitting procedure on absorption spectrum and χ^<(3)> spectrum, the average effective conjugation lengths of the spincoated film and the LB film are estimated to be approximately 20 and 36 thiophene rings, respectively.2) The time-resolved photoluminescence spectrum of a polythiophene derivative has been analyzed from the viewpoint of the vibronic structure and its dynamics. We found that the photoluminescence (PL) originates from two mixed states that consist of the odd-parity 1Bu component and the even-parity 2Ag component. Since the fluorescence from the two states have different time constants and different vibronic structure, the PL shows a biexponential decay and a spectral change. This model also explains the PL spectrum and its dynamics of many other π conjugated polymers quite well.

研究了结构规整的聚噻吩衍生物聚（3-[2-（（S）-2-甲基丁氧基）乙基]噻吩）的激子非线性。我们的研究主要集中在两个方面：1）激子非线性与有效共轭长度的关系; 2）激子的弛豫机制。主要研究结果如下：1）利用简并四波混频方法测量了聚噻吩衍生物聚（3-[2-（（S）-2-甲基丁氧基）乙基]噻吩）的旋涂膜和LB膜在激子共振附近的三阶光学非线性。在共轭聚合物中得到了最大的χ^&lt;（3）&gt;值（~ 10^<-7>esu）。通过对吸收光谱和χ^&lt;（3）&gt;谱的拟合，估算出旋涂膜和LB膜的平均有效共轭长度分别约为20个和36个噻吩环。2）从振动结构和动力学的角度分析了聚噻吩衍生物的时间分辨光致发光光谱。我们发现，光致发光（PL）起源于两个混合状态，包括奇宇称1Bu组件和偶宇称2Ag组件。由于两个态的荧光具有不同的时间常数和不同的电子振动结构，因此PL表现出双指数衰减和光谱变化。该模型也很好地解释了许多其他π共轭聚合物的PL谱及其动力学。

项目成果

T.Kobayashi, et al.: "Fluorescence from the even-parity state in π conjugated polymer"J.Phys.Soc.Jpn.. 70, (in press). (2001)

T.Kobayashi 等人：“π 共轭聚合物中偶宇称态的荧光”J.Phys.Soc.Jpn.. 70，（出版中）。

T.Kobayashi, et al.: "Self-trapped exciton dynamics in highly ordered and disordered films of polythiophene derivative"Phys.Rev.B. 62. 8580-8583 (2000)

T.Kobayashi 等人：“聚噻吩衍生物高度有序和无序薄膜中的自陷激子动力学”Phys.Rev.B。

S.Kishino: "Estimation of the effective conjugation length of polythiophene from its |X^<(3)>(w;w,w,-w)|spectrum at excitonic resonance"Phys.Rev.B. 58. 13430-13433 (1998)

S.Kishino：“根据激子共振下的 |X^<(3)>(w;w,w,-w)| 谱估计聚噻吩的有效共轭长度”Phys.Rev.B。

T. Kobayashi: "Self-trapped exciton dynamics in highly ordered and disordered films of polythiophene derivative"Phys. Rev. B. 62. 8580-8583 (2000)

T. Kobayashi：“聚噻吩衍生物高度有序和无序薄膜中的自陷激子动力学”Phys。

S. Kishino: "Spectra of |X^<(3)>(w ; w, w, -w)|at excitonic resonance in poly (3-[2-((S)-2-methylbutoxy) ethyl]thiophene"Nonlinear Optics. 32. 361-364 (1999)

S. Kishino：“聚 (3-[2-((S)-2-甲基丁氧基)乙基]噻吩中的激子共振 |X^<(3)>(w ; w, w, -w)| 的光谱”