Collaborative Research: Chemical Control of Polymer/PbS Blends for PV Applications

合作提案：PI名称：Moule(Lead)提案编号：1436273机构：加州大学戴维斯分校PI名称：Ganapathysubramanian提案编号：1437636机构：爱荷华州立大学PI名称：Ginger提案编号：1437016机构：华盛顿大学太阳代表着地球上最丰富的潜在无污染能源。基于集成到光伏(PV)设备中的有机聚合物的太阳能电池用于将光转换为电能，如果太阳能转换效率能够提高，则为可再生能源的生产提供了一条潜在的低成本途径。提高有机聚合物太阳能电池效率的关键是更好地了解聚合物薄膜中材料的分子排列。该项目将应用新的电子显微镜工具来了解材料加工如何影响用于光伏(PV)应用的聚合物/纳米颗粒薄膜中材料的三维排列。低成本的PbS纳米粒子与导电聚合物的混合物将被研究，因为这些混合物最近显示出高的光伏效率，而且这些材料在电子显微镜下具有高成像对比度。电子断层扫描将生成混合物中材料的三维浓度图。这些图谱将被用来将加工条件与聚合物/纳米颗粒薄膜内的材料排列相关联。然后，这些信息将与设备性能相关联，以便确定基于有机聚合物制造更好太阳能电池的策略。这项工作将由一个合作团队进行，该团队将同时推进聚合物/纳米颗粒薄膜制造、三维电子显微镜成像和图像计算分析的科学，以揭示纳米级结构。这种协作方法有可能揭示任何其他技术无法测量的光学和电学特性的结构起源。关于扩大参与的教育和活动，该项目将提供一系列不同的外联和教育机会，包括通过童子军和4H与儿童互动，在参加人数众多的当地节日上进行公共教育，在课堂上纳入研究材料，以及留住女工程学学生。该项目将开发和使用新的电子断层扫描工具，以了解材料加工如何影响用于光伏(PV)应用的聚合物/纳米颗粒杂化薄膜中材料的三维排列。低成本的PbS纳米粒子与导电聚合物的混合物将被研究，因为这些混合物最近显示出高的光伏效率，而且这些材料在电子显微镜下具有高成像对比度。该电子显微镜工具基于高角度环形暗场扫描电子断层扫描(HAADF-ET)和离散代数重建技术(DART)相结合，为有机/无机混合光伏材料生成分辨率低于3立方纳米的三维(3D)材料浓度图。将使用基于图形的分析来测量3D数据的形态描述符的发展，包括诸如相的数量、在每个相中的浓度比、域大小、域连通性、路径的曲折性、各向异性和域表面积等特征。这些信息将被用来将有机/无机混合电子薄膜中复合位置的形态、结构异质性和物理分布与光电性能和光伏性能关联起来。关于扩大参与的教育和活动，该项目将提供一系列不同的外联和教育机会，包括通过童子军和4H与儿童互动，在参加人数众多的当地节日上进行公共教育，在课堂上纳入研究材料，以及留住女工程学学生。

Proposals in Collaborative:PI Names: Moule (Lead)Proposal No: 1436273Institution: University of California, Davis PI Name: GanapathysubramanianProposal No:1437636 Institution: Iowa State UniversityPI Name: Ginger Proposal No: 1437016 Institution: University of WashingtonThe sun represents the most abundant potential source of pollution-free energy on earth. Solar cells for conversion of light to electricity based on organic polymers integrated into a photovoltaic (PV) device offer a potentially low-cost route for renewable electricity production if the solar energy conversion efficiency can be improved. The key to improving the efficiency of organic polymer based solar cells is to better understand the molecular arrangement of the materials within the polymer film. This project will apply novel electron microscopy tools to understand how materials processing affects the three-dimensional arrangement of materials in polymer/nanoparticle films designed for photovoltaic (PV) applications. Mixtures of low-cost lead sulfide (PbS) nanoparticles with electrically conducting polymers will be studied because these mixtures have shown recent high photovoltaic efficiency, and because these materials have high imaging contrast by electron microscopy. The electron tomography will generate three dimensional concentration maps of materials within the mixture. These maps will be used to correlate processing conditions to material arrangement within the polymer/nanoparticle film. This information will then be correlated to device performance in order to identify strategies for making better solar cells based on organic polymers. The work will be carried out by a collaborative team that will simultaneously advance the science of polymer/nanoparticle film fabrication, three dimensional electron microscope imaging, and computational analysis of the images to reveal nanoscale structure. This collaborative approach has the potential uncover the structural origin of optical and electronic properties that cannot be measured by any other technique. With respect to education and activities for broadening participation, the project will provide a diverse set of outreach and educational opportunities that include interaction with children through the Boys and Girls Scouts and 4H, public education at well attended local festivals, inclusion of research material in classes, and retention of female engineering students. Technical Description This project will develop and use new electron tomography tools to understand how materials processing affects the three-dimensional arrangement of materials in hybrid polymer/nanoparticle films designed for photovoltaic (PV) applications. Mixtures of low-cost lead sulfide (PbS) nanoparticles with electrically conducting polymers will be studied because these mixtures have shown recent high photovoltaic efficiency, and because these materials have high imaging contrast by electron microscopy. The electron microscopy tool is based on high-angle annular dark-field scanning electron tomography (HAADF-ET) combined with the discrete algebraic reconstruction technique (DART) to generate three-dimensional (3D) material concentration maps with resolution of less than three cubic nanometers for the hybrid organic/inorganic photovoltaic materials. Development of morphology descriptors of the 3D data, including features like the number of phases, concentration ratio in each phase, domain size, domain connectivity, tortuosity of pathways, anisotropy and domain surface area will be measured using graph-based analysis. This information will be used to correlate morphology, structural heterogeneity, and physical distribution of recombination sites in mixed organic/inorganic electronic films to optoelectronic properties and photovoltaic performance. With respect to education and activities for broadening participation, the project will provide a diverse set of outreach and educational opportunities that include interaction with children through the Boys and Girls Scouts and 4H, public education at well attended local festivals, inclusion of research material in classes, and retention of female engineering students.