Charge-Carrier Dynamics in Novel Photorefractive Inorganic: Organic Nanocomposites

本计画主要研究一种新型的无机纳米复合材料--聚合物纳米复合材料中与光折变效应相关的基本过程。 所提出的新一类材料具有希望，因为可以选择性地选择用于光致折射活性的光谱响应以用于在可见光以及近红外通信波长下的操作，主要源自无机系统中的量子限制效应的特征将允许在低操作电压下观察到光致折射效应。 这种新的聚合物材料的光敏化的方法不仅提供了一种方法，通过该方法可以显着增强的特性和过程中涉及的光折变效应，但也提供了机会，研究的基本物理过程的光电荷的产生，迁移，捕获和重组。 光电导性实验将被用于纳米复合材料的光敏性的表征和迁移率数据将从飞行时间实验中获得。 然后使用已建立的模型（例如Onsager重组模型）分析结果。 光折变特性将使用简并四波混频以及非对称两光束耦合技术。 这些实验将提供洞察光栅形成的几个方面，如相移和光栅生长和衰减的动力学。 迁移率的温度依赖性以及光栅动力学实验将为载流子的捕获和释放机制提供额外的见解。新型光学材料的开发应被视为对技术具有潜在的非常重要的影响，并且需要开发无机和有机材料的最佳性能。 在这些领域培养的研究生和博士后学生将有很好的就业前景。

This project focuses on the study of basic processes associated with the photorefractive effect in a novel class of inorganic nanocrystal: polymer nanocomposites. The proposed new class of materials holds promise in that the spectral response for photorefractivity can be selectively chosen for operation at visible as well as near infra-red communication wavelengths, a feature primarily derived from the quantum confinement effect in inorganic systems will allow the photorefractive effect to be observed at low operational voltage. This novel approach to the photosensitization of polymeric materials not only offers a method by which the characteristics and processes involved in the photorefractive effect may be significantly enhanced, but also provides the opportunity to study the fundamental physical processes of photocharge generation, migration, and trapping and recombination. Photoconductivity experiments will be utilized in the characterization of the photosensitivity of the nanocomposite and mobility data will be obtained from time-of-flight experiments. The results will then be analyzed using established model, e.g. the Onsager recombination model. Photorefractive characterizations will be made using degenerate-four-wave-mixing- as well as asymmetric-two beam coupling techniques. These experiments will provide insight into several aspects of grating formation such as phase shift and the kinetics of grating growth and decay. The temerature dependence of the mobility as well as grating kinetic experiments will provide additional insight into the mechanism of trapping and detrapping of carriers.%%%The development of novel optical materials should be reviewed as having potentially a very important impact on technology, and the best properties of both inorganic and organic materials need to be exploited. Graduate and post -doctoral students trained in these areas will have excellent job prospects.