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Elementary excitations in electroluminescent one-dimensional conjugated polymers

电致发光一维共轭聚合物的基本激发

基本信息

批准号：
09440116
负责人：
KURODA Shin-ichi
金额：
$ 1.6万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09440116/
关键词：
Conjugated polymers Electroluminescent polymers Nonlinear excitations Polaron ESR ENDOR One-dimensional electron system

项目摘要

Recent discovery of electroluminescence in a polymer, poly (phenylene vinylene) , PPV has brought much attention to polarons, a nonlinear excitation in one-dimensional conjugated polymers, as a candidate of charge carriers responsible for electroluminescence through charge recombination. We have shown that ESR and ENDOR spectroscopies are useful in observing the microscopic shapes of paramagnetic excitations in conjugated polymers. The purpose of the present project is to conduct ESR and ENDOR observations of polarons generated by light illumination, doping etc. in PPV and its derivatives and to develop a theoretical model to analyze the data to obtain the polaron shapes as well as the electronic states of polymers.In this year, we have been successful in determining the detailed shape of polarons in PPV and the magnitudes of Coulomb interactions affecting the shape by analyzing the ENDOR and newly obtained TRIPLE (electon-nuclear-nuclear triple resonance) data of trapped polarons in the dark state of the polymer, provided from Dr. T.Ohnishi of Sumitomo Chemical Co. The obtained results with the maximum spin densities reside on vinylene sites successfully explained the reduction of ODESR linewidth in a derivative, cyano-PPV where the protons of vinylene sites are substituted by cyano groups, reported by British and American groups. The results have been published in JPSJ.In addition to these, light-induced ESR (LESR) of photogenerated polarons has been successfully detected in cyano-substituted PPV derivatives provided from Prof. R.H.Friend of Cavendish Laboratory. The analysis of the observed LESR line shapes as well as the excitation spectra of LESR intensities are currently under progress to study the effect of molecular structures on the polaron shapes and the electronic states of one-dimensional polymers.

最近发现的一种聚合物--聚苯乙炔的电致发光引起了人们对极化子的关注，极化子是一维共轭聚合物中的一种非线性激发，它是一种通过电荷复合产生电致发光的候选载流子。我们已经证明，ESR和Endor光谱在观察共轭聚合物中顺磁激发的微观形状方面是有用的。本项目的目的是对PPV及其衍生物中由于光照、掺杂等产生的极化子进行ESR和Endor观测，并开发一个理论模型来分析数据，以获得聚合物的极化子形状和电子态。在这一年里，我们通过分析PPV中极化子的详细形状和影响形状的库仑相互作用的大小，通过分析Endor和新获得的聚合物暗状态下捕获的极化子的三重(电子-核-核三重共振)数据，由住友化学株式会社T.Ohnishi博士提供。所获得的最大自旋密度位于乙叉中心的结果成功地解释了一种衍生物氰基PPV中ODESR线宽的减少，其中乙叉中心的质子被氰基取代，这是英国和美国小组报道的。这些结果已经发表在《科学》杂志上。此外，在卡文迪什实验室的R.H.Friend教授提供的氰基取代的PPV衍生物中，还成功地检测到了光生极化子的光诱导ESR(LESR)。为了研究分子结构对一维聚合物极化子形状和电子态的影响，目前正在对观测到的LESR谱线形状以及LESR强度的激发光谱进行分析。