Charge-Carrier Dynamics in Novel Photorefractive Inorganic: Organic Nanocomposites

本项目致力于研究一类新型无机纳米晶：聚合物纳米复合材料中与光折变效应相关的基本过程。提出的新型材料具有很好的前景，因为光折变的光谱响应可以选择性地选择在可见光和近红外通信波长下工作，这一特性主要源于无机系统中的量子限制效应，将允许在低工作电压下观察到光折变效应。这种聚合物材料光敏化的新方法不仅提供了一种可以显著提高光折变效应的特性和过程的方法，而且为研究光电荷的产生、迁移以及陷阱和复合的基本物理过程提供了机会。光电导实验将用于表征纳米复合材料的光敏性，迁移率数据将通过飞行时间实验获得。然后将使用已建立的模型来分析结果，例如Onsager重组模型。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来进行。这些实验将提供对光栅形成的几个方面的洞察，例如相移和光栅生长和衰减的动力学。迁移率与温度的关系以及光栅动力学实验将提供对载流子捕获和去捕获机制的更多洞察力。%新型光学材料的发展应该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.