CAREER: Plasmons for Solar Energy Harvesting

[0955148]光伏太阳能电池技术将在减少碳排放和提供清洁、安全的能源方面发挥至关重要的作用。然而，为了与丰富的、不可再生的燃料（如用于发电的煤）竞争，太阳能电池板的效率必须提高，生产成本必须降低，以降低电力生产的单位成本。一个趋势是减少太阳能电池的厚度，从而减少电荷传输的距离，减少材料的使用，并加快沉积时间。另一个趋势是使用便宜的材料，如TiO2或聚合物。由于更薄的太阳能电池吸收的光更少，因此提高性能和降低成本的方法也有其局限性。为了解决这个问题，支持等离子体的金属粒子有望提高薄太阳能电池吸收光的能力。支持等离子体的金属粒子可以有效地将光耦合到广泛的光伏材料中，而不需要从根本上重新设计设备。本研究将开发用于等离子体介导的太阳能转换的纳米结构材料，并获得对这一过程的基本理解。配体钝化的胶体金属纳米粒子将被用作模型等离子体材料，因为它们的光学、电子和化学性质可以由核和配体壳独立调节。胶体方法还允许颗粒通过各种策略混合或散布在大量的材料中。利用等离子体提高太阳能电池的光吸收有望具有性能增强的特点。具体来说，等离子体的高光吸收率使电子更靠近光阳极，缩短了电荷转移路径，改善了光电流的收集。减少太阳能电池器件堆叠所需的厚度也可以降低材料和加工成本。此外，等离子体激元可以使用新的材料和策略，否则将无法有效地吸收光。这项研究有三个目的。第一个目标是开发新的合成策略来制造用于等离子体光捕获的纳米复合材料和杂化结构。第二个目标是建立金属纳米颗粒和不同光伏介质之间能量传递的基本原理。第三个目标是了解金属纳米颗粒对工作设备中这些材料内电荷输运的影响。所有这些活动都是为了了解等离子体支持的金属纳米颗粒如何在光伏能量捕获和转移系统中发挥作用的基础科学。这项研究的新颖性和智力价值在于，它将提供对核-壳等离子体金属纳米粒子如何影响光伏器件中的光、吸收和电荷转移的基本理解。这项研究具有潜在的变革性，因为等离子体介导的太阳能转换提供了一种全新的可调方法来增强光吸收和增加光电器件的电荷传输，从而提高效率和更薄的器件，从而有可能降低单位发电成本。更广泛的影响这项研究的结果有可能提高太阳能电池的效率和降低成本。这些成果也可能在相关领域取得附带进展，如纳米材料合成、纳米结构薄膜生长和用于生物成像和传感的金属增强荧光。这些教育活动旨在将替代能源和纳米技术研究整合到研究生、本科生、高中生以及高中教师的教育中。对教育的第一个更广泛的影响将是将替代能源和纳米技术纳入本科和研究生课程。第二个更广泛的影响将来自本科和高中学生和教师对化学和材料研究的参与。第三个更广泛的影响是通过网络视频格式的一套模块，教育公众了解一般能源概念，特别是在当前与能源有关的问题方面。

0955148BigioniPhotovoltaic solar cell technologies will play a vital role in efforts to reduce carbon emissions and to provide clean and secure sources of energy. However, to be competitive with abundant, nonrenewable fuels such as coal for electric power production, solar panel efficiencies must be improved, and production costs must be reduced in order to deliver a lower unit cost of electric power production. One trend is to reduce the thickness of the solar cell, which decreases distances for charge transport, reduces materials usage, and speeds up the deposition time. Another trend is to use inexpensive materials such as TiO2 or polymers. Thinning cells to improve performance and reduce costs has its limits, since thinner solar cells absorb less light. To address this problem, plasmon-supporting metal particles offer significant promise to increase the ability of thin solar cells to absorb light. Plasmon-supporting metal particles can be used to efficiently couple light into a broad range of photovoltaic materials, without the need to radically redesign devices. Intellectual MeritThis research will develop nanostructured materials for plasmon-mediated solar energy conversion, and gain fundamental understanding of this process. Ligand-passivated colloidal metal nanoparticles will be used as the model plasmonic material, since their optical, electronic, and chemical properties can be independently tuned by the core and ligand shell. The colloidal approach also allows the particles to be mixed or spread in a wide number of materials by a variety of strategies. Using plasmons to improve light absorption in solar cells is expected to have performance enhancing features. Specifically, the high light absorptivity of plasmons produces electrons closer to the photoanode, shortening the charge transfer path and improving photocurrent collection. The decrease in the necessary thickness for the solar cell device stack could also reduce material and processing costs. Furthermore, plasmons enable the use of new materials and strategies that would otherwise be unable to absorb light efficiently. The research has three aims. The first aim is to develop novel synthesis strategies for making nanocomposite materials and hybrid structures for plasmonic light capture. The second aim is establish the fundamental principles governing energy transfer between metal nanoparticles and different photovoltaic media. The third aim is understand the impact of metal nanoparticles on charge transport within these materials in working devices. All of these activities seek to understand the basic science of how plasmon-supporting metal nanoparticles function in photovoltaic energy capture and transfer systems.The novelty and intellectual merit of this research is that it will provide basic understanding of how core-shell plasmonic metal nanoparticles affect light and absorption and charge transfer in photovoltaic devices. This research is potentially transformative because plasmon-mediated solar energy conversion offers a completely new and tunable approach to enhance light absorption and increase charge transport photovoltaic devices, leading to enhanced efficiency and thinner devices that in turn have the potential to reduce unit electrical power generation costs.Broader ImpactsOutcomes of this research have the potential to improve the efficiency and reduce costs of solar cells. These outcomes could also make collateral advancements in related areas such as nanomaterials synthesis, nanostructured thin film growth, and metal-enhanced fluorescence for biological imaging and sensing.The educational activities are designed to integrate alternative energy and nanotechnology research into the education of graduate, undergraduate, and high school students, as well as high school teachers. The first broader impact on education will be the integration of alternative energy and nanotechnology into the undergraduate and graduate curriculum. The second broader impact will result from the involvement of undergraduate and high school students and teachers in chemical and materials research. The third broader impact is the education of the public on general energy concepts, especially in the context of current energy related issues, through a set of modules in a web-based video format.