Enhanced efficiency in organic photovoltaic cells using engineered plasmonic nanostructures

使用工程等离子体纳米结构提高有机光伏电池的效率

• 批准号: 1067681
• 负责人: Sang-Hyun Oh
• 金额: $ 30万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-04-01 至 2015-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1067681&HistoricalAwards=false
• 关键词: Enhanced; efficiency; organic; photovoltaic; cells

Institution: University of Minnesota-Twin CitiesTitle: Enhanced efficiency in organic photovoltaic cells using engineered plasmonic nanostructuresIntellectual MeritOrganic photovoltaic cells (OPVs) have the potential to redefine the cost of solar energy conversion. Organic semiconductors are attractive due to their compatibility with high throughput processing methods, but demonstrated power conversion efficiencies are only around 7%. The proposed research outlines a new approach to overcome the low absorption efficiency typical in OPVs by exploiting surface plasmons in nanostructured metallic electrodes. Since absorption in OPV materials leads to exciton formation, photocurrent generation requires the dissociation of excitons into their constituent charge carriers. This process usually occurs at a hetero-junction between electron donating (D) and accepting (A) materials. The challenge lies in the fact that the exciton diffusion length is typically shorter than the optical absorption length, necessitating the use of thin active layers to efficiently collect and dissociate excitons. This work integrates thin film OPVs with plasmonic electrodes, permitting sub-wavelength confinement and resonant enhancement of the optical field, to increase the absorption and power conversion efficiencies. The combination of a thin OPV with engineered plasmonic electrodes offers the potential for a high level of tunability and control over the exciton-plasmon coupling to realize high efficiency. In the proposed research, novel architectures that offer optical field enhancement from nanostructured plasmonic electrodes will be introduced to maximize optical absorption in thin OPVs and permit the efficient harvesting of excitons and charge carriers. Extensive computational modeling will be performed to identify optimal design rules for plasmonic OPVs. The use of continuous, nanopatterned metal films is attractive, since the field enhancement is longer range (~200 nm) compared with metallic nanoparticles, enhancing absorption throughout the active OPV layers. Furthermore, these continuous films can concurrently function as electrodes, which is not possible with metallic nanoparticles. For high-throughput fabrication of plasmonic electrodes, a template-stripping method will be used. Using mature silicon fabrication technology, a variety of nano-patterned templates will be fabricated. A metal film deposited on the template will form a smooth surface at the interface, which it can be peeled off of the substrate using an elastomeric stamp and directly transferred to the top of a completed OPV cell using cold welding. This scheme will provide unprecedented flexibility in the fabrication of plasmonic OPVs, since the top and bottom electrodes can be independently nano-patterned with high throughput over large areas. The OPVs proposed in this work will also utilize graded donor-acceptor heterojunctions (GHJs). The use of a GHJ is attractive because it balances the need for efficient exciton diffusion (large interface area) with efficient charge collection (graded pathways for transport). The growth of GHJs is also tunable, enabling a range of compositions through which to examine how the design of plasmonic OPVs is impacted by the spatial D-A composition.Broader ImpactsGraduate students associated with this project will acquire an interdisciplinary spectrum of knowledge in nanofabrication, plasmonics, and molecular photophysics in the context of organic photovoltaic devices for renewable energy. Existing undergraduate research opportunities will be enhanced through continuing relationships with the University of Minnesota UROP program and the NSF REU program. For K-12 education, multiple high school researchers will be hosted and mentored in the PIs laboratory during the summer through the Summer Research Cluster in Renewable Energy program. These activities will be complemented by plans to disseminate results from the proposed work to industry via on-campus workshops and annual hands-on lab short courses for industry participants. Finally, ?Sit with a Scientist? sessions at the Science Museum of Minnesota will be organized through the proposed outreach plan during the one week-long NanoDays event in April of each year.

院校：明尼苏达大学双城分校 使用工程等离子体纳米结构提高有机光伏电池的效率智能优点有机光伏电池（OPV）有可能重新定义太阳能转换的成本。有机半导体由于其与高通量处理方法的兼容性而具有吸引力，但已证明的功率转换效率仅为7%左右。拟议的研究概述了一种新的方法，以克服低吸收效率典型的OPV利用纳米结构的金属电极中的表面等离子体。 由于OPV材料中的吸收导致激子形成，因此光电流产生需要激子解离成其组成电荷载流子。 该过程通常发生在电子供给（D）和接受（A）材料之间的异质结处。 挑战在于激子扩散长度通常短于光学吸收长度的事实，从而需要使用薄的有源层来有效地收集和解离激子。这项工作将薄膜OPV与等离子体电极集成，允许光场的亚波长限制和共振增强，以增加吸收和功率转换效率。 薄OPV与工程化等离子体电极的组合提供了对激子-等离子体激元耦合的高水平可调谐性和控制的潜力，以实现高效率。 在拟议的研究中，将引入从纳米结构等离子体电极提供光场增强的新型架构，以最大化薄OPV中的光吸收，并允许有效地收集激子和电荷载流子。 将进行广泛的计算建模，以确定等离子体OPV的最佳设计规则。 使用连续的纳米图案化金属膜是有吸引力的，因为与金属纳米颗粒相比，场增强的范围更长（~200 nm），增强了整个有源OPV层的吸收。 此外，这些连续膜可以同时用作电极，这对于金属纳米颗粒是不可能的。 对于等离子体激元电极的高通量制造，将使用模板剥离方法。 利用成熟的硅制造技术，将制造各种纳米图案化模板。 沉积在模板上的金属膜将在界面处形成光滑表面，其可以使用弹性体印模从基底剥离，并使用冷焊直接转移到完成的OPV电池的顶部。该方案将在等离子体激元OPV的制造中提供前所未有的灵活性，因为顶部和底部电极可以在大面积上以高通量独立地纳米图案化。在这项工作中提出的OPV也将利用渐变的供体-受体异质结（GHJ）。 GHJ的使用是有吸引力的，因为它平衡了对有效激子扩散（大界面面积）与有效电荷收集（用于传输的分级路径）的需要。 GHJ的增长也是可调的，使一系列的组合物，通过它来检查等离子体OPV的设计是如何受到影响的空间D-A composition.Broader ImpactsGraduate学生与这个项目相关的将获得知识的纳米纤维，等离子体，和分子生物物理学的背景下，可再生能源的有机光伏器件的跨学科光谱。 现有的本科生研究机会将通过与明尼苏达大学UROP计划和NSF REU计划的持续关系得到加强。 对于K-12教育，多名高中研究人员将在夏季通过可再生能源夏季研究集群计划在PI实验室进行托管和指导。 这些活动将辅之以通过校园研讨会和针对行业参与者的年度实践实验室短期课程向行业传播拟议工作成果的计划。 最后，？和科学家坐在一起？明尼苏达州科学博物馆的会议将在每年四月为期一周的NanoDays活动期间通过拟议的外展计划组织。