Polymeric Optoelectronic Devices and Applications

9408810 Peyghambarian这个计划的目标是集中在低维有机系统中新的非线性现象的实验/理论结合研究，开发现实的模型来理解所涉及的基本效应，并利用这些发现来设计和制造新的光电聚合物器件。具体来说，我们的目标有三个：(1)开发和构建用于全息存储和图像处理应用的新型高效光折变聚合物器件。在我们目前的国家科学基金资助下，我们已经获得了最高的衍射效率(大约。34%)的聚合物。获得了可观的双光束耦合增益（30 cm-1），净增益为（6 cm-1）。我们将通过提高光发生效率和电光效应来优化这些器件。(2)电致发光(EL) π共轭聚合物的器件物理学。本项目的目标是通过电子结构、非辐射衰变过程、激发态吸收和光增益研究等实验/理论结合研究，了解聚对苯乙烯（PPV）和相关π共轭聚合物等聚合物材料的电致发光机理。(3)低维有机物中的多激子效应。PI最近报道了在准一维混合堆叠电荷转移有机固体中发现的多激子链和在PPV中发现的双激子。这些结果揭示了新的激发态吸收到更高的多激子态。PI认为，这种多激子状态也会出现在其他准一维材料中，比如分离的堆叠CT固体。＊＊＊

9408810 Peyghambarian The goals of this proposed program are focused toward a combined experiment/theory investigation of new nonlinear phenomena in low- dimensional organic systems, developing realistic models to understand the basic effects involved, and using these findings to design and fabricate novel optoelectronic polymeric devices. Specifically, our goals are threefold: (1) Development and construction of new highly efficient photorefractive polymeric devices for holographic storage and image processing applications. Under our current NSF grant we have obtained the highest diffraction efficiency (approx. 34%) of any polymer so far. A respectable two-beam coupling gain (30 cm-1), with net gain of (6 cm-1, was also obtained. We will optimize these devices by improving the photogeneration efficiency and the electro-optic effect. (2) Device physics of electroluminescent (EL) pi- conjugated polymers. Our goals for this part of the project are to understand the mechanism of electroluminescence in polymeric materials like poly(p-phenylenevinylene) (PPV) and related pi- conjugated polymers through combined experiment/theory studies of the electronic structure, nonradiative decay processes, excited state absorption, and optical gain investigation. (3) Multiexciton effects in low-dimensional organics. The PI's have recently reported the discovery of multiexciton chains in a quasi-one- dimensional mixed-stack charge transfer organic solid and of biexcitons in PPV. These results revealed new excited state absorptions to higher multiexciton states. The PI's believe that such multiexciton states would occur in other quasi-1-d materials like the segregated stack CT solids. ***