Functional Atomic Membranes for High-Performance Organic Photovoltaic Materials

基于有机半导体的有机光伏（OPV）器件由于其强大的光吸收率、经济的制造和可调谐的光电特性，对下一代太阳能电池具有吸引力。然而，尽管有这些优点，opv并没有得到广泛的应用。OPV器件性能的一个限制是OPV对光氧化效应的敏感性，这限制了它们的实际使用寿命。另一个限制是opv的功率转换效率仍然比单结无机光伏器件低几倍。由于有机半导体材料中的电荷和能量输运机制不完善，opv的性能相对较差。在本研究中，提出在OPV器件的有源界面处掺入原子薄石墨烯膜，通过同时增加多种功能来提高OPV器件的稳定性和性能。具体来说，假设这些二维结晶石墨烯膜将赋予OPV器件四种独特的功能。首先，它们将作为不可渗透的扩散屏障，排除氧、水蒸气和来自opv活性层的迁移离子，从而提高有机半导体的稳定性和寿命。其次，石墨烯膜将模板化有机半导体的准外延晶体生长，从而改善电荷和能量传输以及器件性能。第三，石墨烯膜有可能调节有机/有机和有机/电极界面的电荷注入和提取，从而实现额外的器件性能调整能力。最后，提出石墨烯膜将提高opv在柔性衬底上的耐久性。具体地说，提出了石墨烯单层/氧化铟锡（ITO）混合透明导体，其中ITO的裂纹被“愈合”。石墨烯单层桥。研究计划有两个主要目标。第一个目标是了解如何在opv的活性界面上最好地集成、生长和沉积原子级薄的结晶石墨烯或氮化硼膜。第二个目标是评估这些膜在界面处的性能。特别是它们作为扩散屏障的行为，它们对分子模板的影响，它们对电荷和能量输运的调制，以及它们作为混合透明导体的适用性。成功完成所建议的工作可能会提高OPV设备的效率，延长其使用寿命；提高了对原子膜扩散的理解；模板化有机晶体生长的新策略以及对理想界面上电荷和能量输运机制的新认识。拟议的教育和推广计划包括以拟议的研究和太阳能光伏为中心的学生培训、课程开发和公众推广。该教育计划将培养一名研究生和三名本科生参与拟议的研究。原子膜输运的研究将被纳入研究生电子材料课程和本科生输运现象课程。为了吸引公众，PI将与威斯康星大学麦迪逊分校能源研究所合作开发基于网络的太阳能光伏教育模块。此外，PI还举办了一场题为“为什么我的电不是来自太阳？”“太阳能光伏电池的未来材料”将得到改进，然后在当地公共广播系统（PBS）节目中播出。

1033346ArnoldIntellectual MeritOrganic photovoltaic (OPV) devices based on organic semiconductors are attractive for next-generation solar cells because of their strong optical absorptivity, economical fabrication, and tunable optoelectronic properties. However, despite these advantages, OPVs have not found widespread use. One limitation on OPV device performance is the susceptibility of OPVs to photo-oxidation effects, which limits their practical lifetime. Another limitation is that the power conversion efficiency of OPVs is still several times lower than that of single-junction inorganic photovoltaic devices. The relatively poor performance of OPVs is due to the inefficient charge and energy transport mechanisms in organic semiconducting materials. In this research, the incorporation of atomically-thin graphene membranes at the active interfaces of OPV devices is proposed to increase the stability of OPV devices and improve their performance by simultaneously adding multiple functionalities. Specifically, it is hypothesized that these two-dimensional, crystalline, graphene membranes will impart four unique functionalities to OPV devices. First, they will act as impermeable diffusion barriers, excluding oxygen, water vapor, and migrating ions from the active layers of OPVs, thereby enhancing organic semiconductor stability and lifetime. Second, the grapheme membranes will template the quasi-epitaxial crystalline growth of organic semiconductors, thereby improving charge and energy transport and device performance. Third, the grapheme membrane has the potential to modulate charge injection and extraction at the organic/organic and organic/electrode interfaces, to enable an additional device performance tuning capability. Finally, it is proposed that the grapheme membranes will Increase the durability of OPVs on flexible substrates. Specifically, graphene monolayer/indium tin oxide (ITO) hybrid transparent conductors are proposed in which cracks in ITO are ?healed? by grapheme monolayer bridges.The research plan has two major objectives. The first objective is to develop an understanding of how to best integrate, grow, and deposit atomically-thin, crystalline graphene or boron-nitride membranes at the active interfaces of OPVs. The second objective is to evaluate the properties of these membranes at interfaces ? specifically for their behavior as diffusion barriers, their effect on molecular templating, their modulation of charge and energy transport, and their applicability as hybrid transparent conductors. Successful completion of the proposed work may result in higher efficiency OPV devices with extended lifetime; an improved understanding of diffusion through atomic membranes; new strategies for templating organic crystalline growth; and new understanding of charge and energy transport mechanisms across ideal interfaces. Broader Impacts The proposed education and outreach plan includes student training, course development, and public outreach centered on the proposed research and solar photovoltaics. The education plan will train one graduate student and involve three undergraduate students in the proposed research. Research on transport in atomic membranes will be incorporated into graduate level electronic materials course, and an undergraduate transport phenomena course. To engage the public, the PI will work with the UW-Madison Energy Institute to develop web-based educational modules on solar photovoltaics. Furthermore, a public lecture developed by the PI titled "Why doesn't my electricity come from the sun? Future materials for solar photovoltaic solar cells" will be enhanced and then aired on a local Public Broadcasting System (PBS) program.