Charge-Carrier Dynamics in Novel Photorefractive Inorganic: Organic Nanocomposites

本项目旨在研究新型杂化无机-纳米晶中与光折变效应相关的基本过程，其中各种必要的过程发生在不同的纳米域中。这提供了结合两种截然不同的材料(无机和有机)的优点的机会，以优化各种工艺。将研究光电荷产生和电荷载流子动力学的基本过程，以及空间电荷场诱导的液晶纳米液滴的电光取向(双折射)。其目标是制备光谱可调的高性能光折变纳米复合材料。研究了光栅生长和衰减的动力学，以及各种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作技术。此外，他们还将学习不同的尖端表征方案，包括光电导、飞行时间迁移率、简并四波混频和需要使用各种类型的激光光源的两个光束耦合实验。%光折变过程利用光能到电荷的转换和随后的运动。它们在光电子器件中发现了重要的应用，这些光电子器件可用于光放大和电信的波束改进，以及用于纠正基于光的雷达中的波束失真。为了提高这些应用所需的性能，需要在电荷的光生成及其速度方面取得显著的进步。这些改进还将有利于高效太阳能电池的发展，在这种电池中，光可以更有效地转化为电能。这一提议利用纳米技术结合了两种截然不同的材料--有机材料和无机材料--的优点，以生产混合介质，并在不同的纳米尺寸区域分离不同的过程。通过结合所提出的技术，对这种混合介质中的这些过程的基本了解将允许分别对它们进行优化。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，以提高这一关键光子学领域所需的熟练劳动力。这项研究支持了一些与能源相关的技术的进步，例如太阳能，这些技术满足了重要的社会需求。在这些领域接受培训的学生将在高科技就业市场上有效竞争。

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.