CAREER: Very High Efficiency Organic-Based Photovoltaic Cells - Novel Nanostructure and Photon, Exciton, and Electron Management

背景：寻找足够的清洁能源供应以取代日益枯竭和污染的化石燃料，将是未来半个世纪社会面临的首要挑战之一。太阳能是清洁、丰富和可再生的，但在当今世界，它的利用严重不足。一种主要的太阳能利用方法是利用光伏电池将太阳光直接转化为电能；然而，这只占总能源供应的微不足道的一部分，主要是因为光伏组件的制造和安装成本很高。基于有机材料的器件由于其低材料成本、易于加工以及与柔性衬底的兼容性，可以潜在地提供非常低成本的太阳能转换。在过去的二十年里，人们对有机光伏电池有了很大的兴趣，有机光伏电池的功率转换效率已经稳步提高到目前的约5%。然而，不仅这样的效率仍然远远低于理论极限，而且必须大幅提高效率，才能真正使这项技术适合未来的大规模商业应用。智力优点：这项职业计划专注于开发非常高效的有机光伏电池，由于有机电子材料的许多技术优势，这些电池有可能提供低成本的太阳能转换。利用他在器件物理、器件制造、材料加工和表征方面的知识和专业知识，PI将通过使用新颖的纳米结构和方法来管理光子、激子和电子，解决有机光伏电池中的几个基本器件问题。目标是将这些设备的功率转换效率从目前的5%提高到15%-20%。该计划的研究活动包括四个部分：控制制备有利于非常有效的激子解离和电荷传输的交叉型纳米结构施主-受主异质结；研究暗电流的产生机制和材料界面的能级以提高电压输出；利用低禁带有机材料和无机纳米晶体获得近红外光子；以及应用主/客体系统在不牺牲太阳光谱覆盖率的情况下实现长激子扩散长度。更广泛的影响：该计划致力于基础工程科学研究，与电子/光子学具有很强的技术相关性。特别是，利用低成本、高效率的有机光伏电池将太阳能直接转换为电能，将对世界能源供应产生巨大的社会经济影响。此外，国际学生联合会致力于将研究与教育紧密结合，并促进学生在各个层面的参与。已经设计了一项战略教育计划，包括学生培训、课程贡献以及对K-12学生和教师的推广。国际公用事业协会还将与当地公用事业公司合作，向公众进行教育和宣传。

Background: Finding sufficient supplies of clean energy to replace the depleting and polluting fossil fuels will be one of society's foremost challenges for the next half-century. Solar energy is clean, abundant and renewable, yet it is vastly under-utilized in the current world. One major solar energy utilization approach is the direct conversion of sunlight to electricity using photovoltaic cells; however this has only constituted a negligible portion of the overall energy supply, mainly due to the high manufacturing and installation costs of photovoltaic modules. Devices based on organic materials can potentially provide very low cost solar energy conversion due to their low material cost, ease of processing, and compatibility with flexible substrates. There have been considerable interests in organic-based photovoltaic (OPV) cells in the last two decades, and the power conversion efficiency of OPV cells has steadily improved to the current record of approximately 5%. However, not only such efficiencies are still far lower than the theoretical limits, but it is imperative to greatly improve the efficiency to really make this technology suitable for future large-scale commercial applications.Intellectual Merit: This CAREER proposal focuses on developing very high efficiency, organic-based photovoltaic cells, which have the potential to provide low cost solar energy conversion due to many technological advantages of organic electronic materials. Utilizing his knowledge and expertise in device physics, device fabrication, material processing, and characterization, the PI will address several fundamental device issues in organic photovoltaic cells by employing novel nanostructures and approaches to manage the photons, excitons, and electrons. The goal is to thrust the power conversion efficiency of these devices from the current 5% mark to the 15-20% regime. The research activities of this program consist of four components: controlled fabrication of an interdigitated nanostructured donor-acceptor heterojunction conducive to very efficient exciton dissociation and charge transport; study of the mechanisms contributing to the dark current and the energetics at the material interface to increase the voltage output; harvest of near-infrared photons with low-gap organic materials and inorganic nanocrystals; and application of the host/guest system to achieve long exciton diffusion lengths without sacrificing the coverage of the solar spectrum. Broader Impacts: This program addresses fundamental engineering science research with strong technological relevance to the electronics/photonics. In particular, direct conversion of solar energy to electricity using low-cost, high efficiency organic-based photovoltaic cells will have a tremendous socio-economical impact on the world's energy supply. Moreover, the PI is committed to closely integrate research and education, and to promote student's involvement at all levels. A strategic educational program has been designed to include student training, curriculum contribution, and outreach to K-12 students and teachers. The PI will also work with the local utility company to educate and outreach to the general public.