Optical properties of nanostructured thin films and applications

纳米结构薄膜的光学性质是一个重要的战略研究领域，由于研究单个纳米颗粒和纳米颗粒组装的新工具的开发，纳米结构薄膜的光学性质迅速发展。这一领域在纳米制造和纳米颗粒合成方面取得了显著进展，可以根据特定的性质和应用精细地控制尺寸、形状和几何排列等参数。拟议的研究将致力于纳米结构薄膜或纳米粒子系统的光学性质，重点是等离子体薄膜的特殊光学性质，以进一步促进对此类薄膜或系统与其纳米结构和预期应用之间的行为的当前理解。 为了实现我们的目标，现提出如下建议。将进行高级理论建模，以探索各种纳米颗粒的不同特性，从简单的球形到复杂和具有挑战性的构型。我们的工作将特别探索以前没有研究过的不同类型的不对称纳米粒子集合，根据我们最近的探索性工作，这些不对称纳米粒子集合可以呈现出感知环境变化的特殊品质。电子光刻将用于制备优化的耦合粒子器件，可以用高精度的扫描近场光学光谱来表征。还将详细研究金属纳米棒复合材料的非线性磁化率随颗粒取向和填充因子的变化，并建立理论模型对结果进行分析。这种类型的材料将在亚波长尺度的器件中进行超快、低功耗的全光信息处理，具有巨大的潜力。纳米结构薄膜的其他应用将被实现，特别是在创新和高效的光伏以及智能可切换涂层的设计方面。等离子体纳米结构将允许我们在太阳能电池中管理纳米级的光，以便增加设备的吸收，从而提高性能。用有效介质理论描述等离子体有源层的光学性质的光电子学模型和有机半导体模型将被用来研究等离子体粒子对短路光电流的影响。高质量的等离子体有机太阳能电池将被制造出来并进行相应的测试。就其本身而言，纳米结构电致变色薄膜可能会增加智能涂层的响应时间，使其很容易应用于智能窗户、可切换眼镜或显示器。为此，我们建议充分挖掘掠角沉积(GRAID)方法在制备薄膜方面的潜力，以创建所需的孔隙率和有利于离子在电致变色材料中传输的纳米通道网络。将进行相关的测量，以确定纳米结构和样品孔隙率与材料性能之间的关系，特别是响应速度。 总之，提出的研究计划是一个全面的、原创的和具有挑战性的计划，涵盖了基本原理、理论、线性和非线性光学性质的建模以及器件制造和表征等方面，并有可能将技术转移到工业中。

The optical properties of nanostructured thin films constitute an important and strategic area of research, evolving rapidly thanks to the development of new tools for investigating single nanoparticles as well as assemblies of nanoparticles. This area has seen remarkable progress made in nanofabrication and nanoparticle synthesis that can allow the fine control of parameters such as size, shape and geometric arrangement for specific properties and applications. The proposed research will work on the optical properties of nanostructured thin films or nanoparticle systems, with an emphasis on the exceptional optical properties of plasmonic films, to further advance the current understanding of the behavior of such films or systems in relation with their nanostructures and the intended applications. In order to achieve our goals, the following is proposed. Advanced theoretical modeling will be performed to explore the different characteristics of various nanoparticles, from the simple spherical shape to complex and challenging configurations. Our work will explore in particular different types of asymmetrical nanoparticle ensembles not studied previously that, according to our recent exploratory work, can present exceptional qualities for sensing environmental changes. Electron lithography will be used for preparing optimized coupled-particle devices that can be characterized by high precision scanning near-field optical spectroscopy. The nonlinear susceptibility of metallic nanorod composites will also be studied in detail as a function of the particle orientation and filling factor, and a theoretical model developed will be used for analysis of the results. Such a type of materials would have great potential for ultrafast, low power all-optical information processing in subwavelength-scale devices. Other applications of nanostructured films will be realized, particularly in the design of innovative and efficient photovoltaics and smart switchable coatings. Plasmonic nanostructures will allow us to manage light at the nanoscale in solar cells in order to increase the device absorption that would lead to enhanced performance. An optoelectronic model with the optical properties of the plasmonic active layers described by an effective medium theory and an organic semiconductor model will be used to study the short-circuit photocurrent influenced by the plasmonic particles. High quality plasmonic organic solar cells will be fabricated and tested accordingly. For their part, nanostructured electrochromic films will likely increase the response times of smart coatings making them readily applicable to smart windows, switchable eyewears or displays. To this aim, we propose to explore fully the potential of the glancing angle deposition (GLAD) method for fabricating thin films to create the desired porosity and a network of nanochannels which would favor ion transport in the electrochromic material. Pertinent measurements will be made for establishing the relationship between nanostructures and sample porosity with the material performance and in particular the response speeds. In summary, the research program proposed is a comprehensive, original and challenging one covering aspects of fundamentals, theory, modeling of linear and nonlinear optical properties as well as device fabrication and characterization, with a potential transfer of technology to industry.