EAGER: Plasmonic Transparent Electrodes for Organic Photovoltaics

摘要：非技术：光伏设备有潜力通过将太阳能转化为电能来提供无限的能源。与无机材料制造的光电器件相比，有机材料制造的光电器件具有显著的优势。这些优点包括低成本，重量轻，灵活性，以及与卷到卷的大批量加工的兼容性。然而，有机光伏器件的广泛采用受到其相对较低的功率转换效率和目前使用的铟锡氧化物透明电极，特别是柔性器件的机械性能差的限制。铟锡氧化物薄膜的脆性可能使其与低成本、卷对卷、大批量加工和柔性有机太阳能电池的制造不相容。这个EAGER项目将研究新型等离子体纳米结构透明电极，以替代目前在有机太阳能电池中使用的氧化铟锡透明电极。新型等离子体透明电极将显著增强有机光收集层的光子吸收，从而提高有机太阳能电池的功率转换效率。利用所提出的等离子体纳米结构的双重性质的概念是新颖的和变革性的，因为它将使铟锡氧化物的替代材料不仅作为透明电极更优越，而且具有额外的关键功能，这将提高设备的功率转换效率，并导致低成本光伏设备的大规模生产。该项目将有助于提高美国在可再生能源领域的竞争力。技术：该项目将研究新型金属纳米结构，其中表面等离子体共振的衰减长度与有机光收集层的厚度具有相同的数量级。这些新型透明电极已经通过模拟显示，在有机光伏器件中，有机有源光收集层的总光子吸收方面产生了最高的增强。将研究两种不同类型的等离子体纳米结构（单面和双面），并研究每种类型的各种几何形状，并与先前的模拟结果进行比较。在设备加工和表征过程中，将使用一个集成的实验装置来防止银电极和有机材料的任何空气/水分暴露。为了在有机光电器件中实现等离子体纳米结构电极，我们将研究压印和模板两种不同的光刻技术。该项目将寻求通过实验测量增强的光子吸收，并证明它可以转化为增加的短路电流密度，从而显着提高功率转换效率。揭开导致这种增强的物理和机制，并确定可能干扰它们的任何瓶颈，将提高我们对等离子体和有机纳米结构之间相互作用的认识和理解。这将使所提出的等离子体透明电极能够在其他薄膜光电器件中实现，例如有机生物传感器，从而为许多其他应用和使能技术打开大门。利哈伊大学的PI在招收少数族裔方面有着良好的记录，并将继续在暑期项目中为代表性不足的群体提供机会。PI还计划追求NSF-REU（本科生研究经验），以促进本科生的参与，重点是少数民族学生的招募。

Abstract:Nontechnical:Photovoltaic devices have the potential to provide an unlimited source of energy by converting solar light into electricity. Photovoltaic devices made with organic materials offer significant advantages compared to ones made with inorganic materials. These advantages include low-cost, light-weight, flexibility, and compatibility with reel-to-reel high-volume processing. However, widespread adoption of organic photovoltaic devices is limited by their relatively low power conversion efficiency, and the poor mechanical properties of the currently used indium-tin-oxide transparent electrode, especially for flexible devices. The brittleness of indium-tin-oxide thin films may render them incompatible with low cost, reel-to-reel, high volume processing and manufacturing of flexible organic solar cells. This EAGER project will investigate novel plasmonic nanostructured transparent electrodes as replacement for the currently used indium-tin-oxide transparent electrodes in organic solar cells. The new plasmonic transparent electrodes will significantly enhance the photon absorption in the organic light-harvesting layer(s) and thus improve the power conversion efficiency of the organic-based solar cells. The concept of taking advantage of the dual nature of the proposed plasmonic nanostructures is novel and transformative as it will enable the replacement of indium-tin-oxide with a material not only more superior as a transparent electrode but with an additional crucial function, which will boost the device power conversion efficiency and lead to large-scale manufacturing of low cost photovoltaic devices. This project will contribute to building US competitiveness in the field of renewable energy sources. Technical:This project will investigate novel metallic nanostructures in which the decay length of surface plasmon resonances is of the same order of magnitude as the thickness of the organic light-harvesting layer(s). These novel transparent electrodes have been shown via simulations to yield the highest reported enhancement in total photon absorption of the organic active light-harvesting layer(s) in an organic photovoltaic device. Two different types (single- and double-sided) of plasmonic nanostructures will be investigated and, various geometries from each type will be studied and compared to prior simulation results. An integrated experimental set-up will be used to prevent any air/moisture exposure of the silver electrode and of the organic materials during device processing and characterization. Two different lithographic techniques imprint and stencil will be pursued in order to realize the plasmonic nanostructured electrodes in organic photovoltaic devices. This project will seek to measure experimentally the enhanced photon absorption and demonstrate that it can be translated into an increased short-circuit current density resulting in a significantly enhanced power conversion efficiency. Unravelling the physics and the mechanism(s) that result in such an enhancement, and identifying any bottlenecks that may interfere with them, will advance our knowledge and understanding of the interactions between plasmonic and organic nanostructures. This will enable the proposed plasmonic transparent electrodes to be implemented in other thin film optoelectronic devices, such as organic biosensors, thus opening the door for many other applications and enabling technologies.The PI at Lehigh University has the track record in recruiting minorities and will continue to provide opportunities for underrepresented groups in the summer programs. The PI also plans to pursue NSF-REU (Research Experience for Undergraduates) to foster undergraduate participation with an emphasis on minority student recruitment.