Charge-Carrier Dynamics in Novel Photorefractive Inorganic: Organic Nanocomposites

本项目旨在研究包含聚合物-分散-液晶纳米复合材料的新型杂化无机-纳米晶体的光折变效应的基本过程，其中各种必要的过程发生在不同的纳米畴中。这为结合无机和有机这两种截然不同的材料的优点，以优化各种工艺提供了机会。研究了光电电荷产生的基本过程和载流子动力学，以及空间电荷场诱导液晶纳米液滴的电光取向（双折射）。目标是生产光谱可调的高性能光折变纳米复合材料。研究了光栅的生长和衰减动力学以及不同液晶参数对光折变效率的影响。该项目将使研究生接触到最先进的纳米晶体合成和样品制造技术。此外，他们将学习不同的前沿表征方案，包括光导率，飞行时间迁移率，简并四波混频和需要使用各种类型激光源的两束耦合实验。光折变过程利用光能转化为电荷及其随后的运动。他们在光电器件中发现了重要的应用，这些器件可用于光学放大和电信的光束改进，以及光基雷达中的光束畸变校正。为了在这些应用中产生必要的性能改进，需要在光电产生电荷及其速度方面取得重大进展。这些改进也将有利于高效太阳能电池的发展，使光能更有效地转化为电能。该方案利用纳米技术将有机和无机两种截然不同的材料的优点结合起来，产生混合介质，并在不同的纳米尺寸区域分离各种工艺。通过结合所提出的技术，对混合介质中这些过程的基本理解将允许它们分别进行优化。拟议研究的一个有价值的部分将是为研究生提供广泛的培训，以提高这一重要光子学领域所需的熟练劳动力。这项研究支持了许多能源相关技术的进步，例如解决重要社会需求的太阳能。在这些领域受过训练的学生将在高科技就业市场上有效地竞争。

This project aims to study basic processes associated with the photorefractive effect in novel hybrid inorganic-nanocrystals containing polymer-dispersed-liquid-crystal nanocomposites, where the various necessary processes take place in different nanodomains. This provides the opportunity to combine the merits of the two widely different classes of materials, inorganic and organic, to optimize the various processes. Fundamental processes of photo-charge generation and charge-carrier dynamics as well as the space charge field induced electro-optic orientation (birefringence) of the liquid crystal nanodroplets will be studied. The goal is to produce spectrally tunable high performance photorefractive nanocomposites. The kinetics of grating growth and decay and the effect of various liquid crystal parameters on the photorefractive efficiency will be investigated. The project will expose graduate students to state-of-the art nanocrystals synthesis and sample fabrication techniques. Also, they will learn about different cutting-edge characterization schemes including photoconductivity, time-of-flight mobility, degenerate four wave mixing and two beam coupling experiments requiring the use of various types of laser sources.%%%Photorefractive processes utilize conversion of light energy to electrical charges and their subsequent movement. They find important applications in optoelectronic devices that are useful for optical amplification and beam improvement for telecommunications, as well as for correction of beam distortion in light based radar. In order to produce the improvement in performance necessary for these applications, significant gains in the photogeneration of charges and their speed are needed. These improvements will also benefit the development of highly efficient solar cells where light can be transformed more efficiently to electricity. This proposal utilizes nanotechnology to combine the merits of two widely different classes of materials, organic and inorganic, to produce hybrid media and separate the various processes in different nanosize regions. By a combination of the proposed techniques, a fundamental understanding of these processes in this hybrid media will permit their optimization separately. A valuable part of the proposed research will be to provide broad based training of graduate students to enhance the skilled workforce needed in this vital area of photonics. This research underpins advances in a number of energy related technologies, such as solar energy, that address important societal needs. Students trained in these areas will compete effectively in high technology job markets.