SOLAR: Hybrid Semiconductors: Overcoming the Excitonic Bottleneck in Low Cost Solar Cells

技术总结：以环境可持续的方式满足世界不断增长的人口的能源需求是当今社会面临的最重要的科学挑战之一。该研究项目寻求在低成本方法上的革命性突破，以有效地收集太阳能并将其转化为电能，通过追求以下问题：能否发明一种全新的半导体，在光激发下产生离域激子，提出更好地收集太阳能的新策略，并在光伏设备中提供增强的电荷传输和收集？为了实现这些目标，该项目汇集了化学（Prezhdo, Jenekhe, Luscombe），数学（Chen）和材料科学（Cao, Schlaf, Luscombe, Jenekhe）的研究人员，探索用于低成本太阳能电池的新型混合半导体的分子水平合成，电子结构表征和电荷传输。计划的研究将：(1)设计和合成一类全新的半导体，由有机-有机和有机-无机混合半导体组成，具有工程电子、光学和电荷输运特性；(2)利用光电发射光谱（PES）和逆光电发射光谱（IPES）测定了这些新型杂化材料的详细电子结构；(3)测定了有机-有机和有机-无机杂化半导体的光学和电荷输运性质；(4)开发一种新的数学方法来理解混合半导体和相关光伏器件中电荷的分离、湮灭和输运；(5)探索太阳能电池中的新型混合半导体。非技术概要：太阳代表着地球上最丰富的潜在的无污染能源。然而，与化石燃料相比，目前光伏技术的能源过于昂贵。我们需要新的半导体材料和器件，这些材料和器件可能会彻底改变太阳能转换技术，使其在成本上具有化石燃料的竞争力。该项目汇集了几位具有化学、材料科学和数学研究专长的科学家，以开发发明新型半导体和新型光伏设备所需的基础知识，从而更有效地将阳光转化为电能。该项目的成果将导致具有高转换效率的新一代低成本太阳能电池，从而有助于解决社会面临的能源和环境挑战。该项目还为在能源科学和技术高度跨学科领域培训科学家和工程师（包括妇女和少数民族）提供了极好的机会，这些领域需要化学、物理、材料科学、数学和工程方面的知识。关于太阳能材料、设备和技术的新课程将在本科和研究生阶段开发和教授。该项目的高级研究人员长期以来一直让本科生、女性和少数族裔学生参与他们的个人研究项目。这些努力将通过这个小组项目继续和扩大。该项目的研究人员与日本、中国、德国、比利时、韩国、台湾、瑞士、波兰、英国和乌克兰的科学家在能源和电子领域进行了许多研究合作；他们接待了来自其中一些国家的资深科学家和学生的访问。这个项目将加强这些国际合作。

TECHNICAL SUMMARY:Meeting the energy needs of the world's growing population in an environmentally sustainable way is among the most important scientific challenges facing society today. This research project seeks transformative breakthroughs in the low-cost approach to efficient harvesting and conversion of solar energy into electricity by pursuing the following question: can an entirely new class of semiconductors be invented that generates delocalized excitonic species upon photoexcitation, presents new strategies for better harvesting of solar energy, and offers enhanced charge transport and collection in photovoltaic devices? Toward these ends, the project brings together investigators in chemistry (Prezhdo, Jenekhe, Luscombe), mathematics (Chen), and materials science (Cao, Schlaf, Luscombe, Jenekhe) to explore molecular level synthesis, characterization of electronic structure, and charge transport of a novel class of hybrid semiconductors for applications in low-cost solar cells. The planned research will: (1) Design and synthesize an entirely novel class of semiconductors, consisting of organic-organic and organic-inorganic hybrid semiconductors with engineered electronic, optical, and charge transport properties; (2) Determine the detailed electronic structure of these novel hybrid materials by photoemission spectroscopy (PES) and inverse photoemission spectroscopy (IPES); (3) Determine the optical and charge transport properties of the organic-organic and organic-inorganic hybrid semiconductors; (4) Develop a new mathematical approach to understanding the separation, annihilation, and transport of charges in hybrid semiconductors and associated photovoltaic devices; and (5) Explore the new hybrid semiconductors in solar cells. NON-TECHNICAL SUMMARY:The sun represents the most abundant potential source of pollution-free energy on earth. However, energy from current photovoltaic technologies is too expensive compared with that from fossil fuels. Novel semiconductor materials and devices that could potentially revolutionize solar energy conversion technologies, making them cost-competitive with fossil fuels, are needed. This project brings together several scientists with research expertise in chemistry, materials science, and mathematics to develop the basic knowledge needed for inventing new semiconductors and new photovoltaic devices for more efficient conversion of sunlight into electricity. Results from the project will lead to new generations of low-cost solar cells with high conversion efficiency and thereby contribute to addressing the energy and environmental challenges faced by society. The project also provides excellent opportunities for the training of scientists and engineers, including women and minorities, in the highly interdisciplinary fields of energy science and technologies, which require knowledge of chemistry, physics, materials science, mathematics, and engineering. New courses on solar energy materials, devices, and technologies, will be developed and taught at the upper undergraduate and graduate student levels. The project's senior investigators have a longstanding history of involvement of undergraduate, women, and minority students in their individual research programs. These efforts will be continued and expanded through this group project. The project's investigators have many research collaborations with scientists in Japan, China, Germany, Belgium, South Korea, Taiwan, Switzerland, Poland, UK, and Ukraine in the general areas of energy and electronics; they have hosted visits by senior scientists and students from some of these countries. This project will strengthen those international collaborations.