Understanding Molecular And Photo-Assisted Doping of Organic Electronic Materials

低成本和可靠的太阳能发电对于减轻气候变化的持续影响和建立可持续能源的未来至关重要。金属卤化物钙钛矿太阳能电池因其低温可加工性、丰富的材料成分和溶液可加工性而成为太阳能市场的颠覆性竞争者。然而，它们的设备寿命短仍然是影响其经济竞争力的主要障碍。与钙钛矿活性层界面的电荷传输层对太阳能电池的效率和寿命都起着至关重要的作用。对电荷传输层的广泛研究已经显著提高了效率和使用寿命，其中spiro-OMeTAD由于其优异的电性能而成为研究最广泛的一种。然而，目前的spiro-OMeTAD掺杂方法导致有害的副产物形成，阻碍了钙钛矿太阳能电池的可扩展性和寿命。本研究旨在通过开发一种新的掺杂工艺来有效地抑制或消除这些副产物的形成，从而克服这些挑战。这项研究的结果有可能影响依赖于有机半导体的各个领域，包括场效应晶体管、光伏、发光二极管和有机光电探测器。它有望通过提高掺杂效率、抑制副产物形成、实现均匀掺杂以及实现可靠和可扩展的加工，为提高有机半导体器件的性能、可扩展性和稳定性做出重大贡献。此外，该项目的资金将通过纽约大学科学与工程应用研究创新（ARISE）项目，为来自代表性不足社区的10年级和11年级高中学生提供实验室体验，为钙钛矿太阳能电池的研究提供宝贵的机会。我们的团队开发了一种新的掺杂方法，利用工艺气体和紫外光氧化含有LiTFSI的Spiro-OMeTAD溶液。这种方法提高了薄膜的导电性、耐久性，并降低了副产物的浓度。尽管存在显著的能级障碍，但它已证明在提高各种有机聚合物的电导率方面具有功效。然而，在完全溶液处理的掺杂方案中，掺杂成分和能量学的设计标准尚不清楚。本项目旨在了解有机电子的分子和光辅助掺杂的潜在机制。集成工程，化学和物理，它提供了一种新的方法来调整有机基电子材料的性质，提高导电性，均匀性和稳定性。我们的第一个目的是探讨金属- tfsi盐的阳离子取代对反应途径、副产物浓度和铸膜光电性能的影响。第二个目标是探讨光强、波长、气体种类和溶剂性质对具有有利和不利能级排列的共轭聚合物体系掺杂效率的影响。通过研究这些机制及其在光电性能中的作用，我们寻求提高掺杂效率、保留率、均匀性，并扩大有机半导体薄膜中可用掺杂物质的范围。这些进步将极大地促进钙钛矿太阳能电池技术的发展，促进从化石燃料向清洁能源的过渡，并使成本效益高、可扩展的制造技术满足日益增长的需求。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Low-cost and reliable solar energy generation is crucial for mitigating the ongoing effects of climate change and establishing a sustainable energy future. Metal-halide perovskite solar cells have emerged as disruptive contenders in the solar market due to their low-temperature processability, abundant material composition, and solution processability. However, their short device lifespan remains a major obstacle to their economic competitiveness. The charge transport layers that interface with the perovskite active layer play a critical role in both the efficiency and lifespan of these solar cells. Extensive research on charge transport layers has led to significant improvements in efficiency and lifespan, with spiro-OMeTAD being the most extensively studied due to its excellent electrical properties. However, current doping methods for spiro-OMeTAD result in detrimental byproduct formation, impeding the scalability and lifespan of perovskite solar cells. This research aims to overcome these challenges by developing a novel doping process that effectively inhibits or eliminates the formation of these byproducts. The outcomes of this study have the potential to impact various fields relying on organic semiconductors, including field-effect transistors, photovoltaics, light-emitting diodes, and organic photo-detectors. It is expected to contribute significantly to improving the performance, scalability, and stability of organic semiconductor-based devices by enhancing doping efficiency, suppressing byproduct formation, achieving uniform doping, and enabling reliable and scalable processing. Furthermore, the funding from this project will support a laboratory experience for grade 10 and 11 high school students from underrepresented communities through the Applied Research Innovations in Science and Engineering (ARISE) program at New York University, providing valuable opportunities for research on perovskite solar cells.Our group has developed a new doping method utilizing a process gas and ultraviolet light to oxidize Spiro-OMeTAD solutions containing LiTFSI. This method improves film conductivity, durability, and reduces byproduct concentration. It has demonstrated efficacy in increasing conductivity of various organic polymer species, despite significant energy level barriers. However, the design criteria for dopant composition and energetics in fully solution-processed doping schemes are unclear. This project aims to understand the underlying mechanism of molecular and photo-assisted doping of organic electronics. Integrating engineering, chemistry, and physics, it offers a novel approach to tuning the properties of organic-based electronic materials, enhancing conductivity, uniformity, and stability. Our first aim explores the effects of cationic substitution of metal-TFSI salts on reaction pathways, byproduct concentration, and optoelectronic properties of cast films. The second aim probes the impacts of light intensity, wavelength, gas species, and solvent properties on doping efficiency in conjugated polymer systems with favorable and unfavorable energy level alignments. By investigating these mechanisms and their role in optoelectronic properties, we seek to improve doping efficiency, retention, uniformity, and expand the range of available dopant species in organic semiconducting films. These advancements will significantly contribute to perovskite solar cell technology, facilitating the transition from fossil fuels to clean energy and enabling cost-effective, scalable manufacturing techniques to meet increasing demand.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.