Quantifying and Improving Structure-Function Relationships of All-Small-Molecule Organic-Solar-Cells

太阳能电池是减少发电过程中温室气体排放的有效方法。除了应对气候变化带来的重大社会挑战外，有机太阳能电池（OSC）还具有许多令人兴奋的新应用，这是由于其卓越的物理特性使其有别于其他太阳能电池技术。它们的机械灵活性允许集成在可穿戴纺织品和电子设备中，轻质和透明的设计允许部署和改造为温室的外墙，低成本与高效的室内操作相结合，使OSC能够为物联网（IoT）提供低功耗传感器。总的来说，OSC提供了一种具有成本效益，可扩展和环保的可再生能源生产方式。OSC的广泛商业成功需要进一步提高效率，并更加关注工业相关技术的研究。拟议的研究将确定和改善OSC中的关键物理过程。应用材料与工业生产高度相关。因此，我寻求突破当今功率转换效率（PCE）限制的途径，并寻求推动该技术的商业化。为了确定对现实世界经济影响的途径，有必要看看有机发光二极管（OLED）建立的先例。OLED的商业成功是由所谓的“小分子”刺激的，这些小分子提供了可重复的合成和纯化，以及多年的长期设备稳定性。同样，小分子（SM）而不是聚合物是升级工业OSC生产的最可能材料选择。就器件功能而言，OSC应用两种分子物质的紧密混合物来从入射光产生电力。分子相对于彼此的结构排列对效率的复杂影响是一个蓬勃发展的研究领域。最近，这两种物质的混合已被确定为影响OSC性能的关键结构特性。拟议的研究重点是无聚合物的全小分子OSC（ASM-OSC）。我工作的核心目标是建立定量模型，将OSC混合物中的混合行为与其光电性能及其产生的性能联系起来。从那里，新的分子和沉积过程的设计准则，并付诸实践。实现这些目标的核心是先进的光电测量，以表征能量景观以及电荷载流子的传输和复合动力学。从溶液和真空中沉积的ASM-OSC的整体研究产生了结构-功能-性能关系的全面和广泛适用的定量描述。所开发的模型、指南和提高的效率有助于溶液和真空处理OSC技术的进步。这两种沉积途径都与工业生产高度相关。拟议的工作将为ASM-OSC带来前所未有的高PCE，从而促进该技术的商业成功。最终，所开展的研究旨在减少全球二氧化碳排放量，以应对气候变化，并促进英国和世界各地的制造业和创新应用。牛津大学凝聚态物理系为我的研究提供了理想的环境，拥有出色的光电表征设施和出色的制造工具，如EPSRC授予的国家薄膜集群。来自学术界和工业界的国家和国际合作伙伴将通过基于同步加速器的结构表征、超快光谱、分子模拟、新分子合成以及确定将研究成果转化为商业应用的方法来支持我的研究。

Solar cells are an effective way to reduce greenhouse gas emissions from the generation of electricity. Apart from contributing to the major societal challenge that climate change poses, organic solar cells (OSCs) have many exciting new applications resulting from their remarkable physical properties that sets them apart from other solar cell technologies. Their mechanical flexibility allows the integration in wearable textiles and electronic appliances, lightweight and semitransparent designs allow the deployment and retrofitting as facades for greenhouses, and low costs combined with efficient indoor operation makes OSCs feasible to supply low-power sensors for the internet of things (IoT). Overall, OSCs offer a cost-effective, scalable, and environmentally friendly way of generating renewable energy. Wide commercial success of OSCs requires further improvements in efficiency, and a stronger focus in research on industrially relevant technologies. The proposed research will identify and improve critical physical processes in OSCs. The applied materials are highly relevant to industrial production. I thereby pursue pathways to break today's limits in power conversion efficiency (PCE) and seek to push the commercialization of the technology. To identify routes towards real-world economic impact, it is worth looking at the precedent established by organic light emitting diodes (OLEDs). The commercial success of OLEDs was stimulated by so-called 'small molecules' that offer reproducible synthesis and purification, as well as longterm device stability over several years. Similarly, small molecules (SMs) rather than polymers are the most likely material choice for upscaled industrial OSC production. In terms of device function, OSCs apply an intimately mixed blend of two molecular species to generate electrical power from incoming light. The complex influence on the efficiency by the structural arrangement of molecules relative to each other is a flourishing field of research. Recently, the intermixing of the two species has been identified as the key structural property to affect OSC performance. The proposed research focuses on polymer-free All-Small-Molecule OSCs (ASM-OSCs). The core objective of my work is to build quantitative models that relate the mixing behaviour in an OSC blend to its optoelectronic properties and the resulting performance. From there, guidelines for the design of novel molecules and the deposition process are drawn and put into practice. Central to achieving these objectives are advanced optoelectronic measurements to characterize the energetic landscape and the transport and recombination dynamics of charge carriers. The holistic study of ASM-OSCs deposited from solution and in vacuum yields comprehensive and widely applicable quantitative descriptions of structure-function-performance relationships. The developed models, guidelines, and improved efficiency contribute to the advancement of solution- and vacuum processed OSC technology. Both deposition routes are highly relevant to industrial production. The proposed work will result in unprecedented high PCEs for ASM-OSCs and thereby facilitate the technology's commercial success. Ultimately, the undertaken research aims at reducing global CO2 emissions to tackle climate change, and to foster manufacturing and innovative applications in the UK and worldwide.The Department of Condensed Matter Physics at the University of Oxford offers the ideal environment for my research with excellent facilities for optoelectronic characterization and outstanding fabrication tools such as the EPSRC-awarded national thin-film cluster. National and international partners from academia and industry will support my research through synchrotron-based structural characterization, ultrafast spectroscopy, molecular simulations, synthesis of new molecules, and identification of ways to transfer research findings into commercial applications.