Heavy-Atom-Free Sensitizers for NIR-to-Visible Solar Photon Upconversion

用于近红外到可见太阳光子上转换的无重原子敏化剂

• 批准号: 2312480
• 负责人: Cody Schlenker
• 金额: $ 68.6万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-15 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2312480&HistoricalAwards=false
• 关键词: Heavy; Atom; Free; Sensitizers; NIR

Non-technical DescriptionHarvesting solar energy efficiently and inexpensively is a grand challenge to producing clean, sustainable energy. The spectrum of light emitted by the sun spans a vast range, from the far infrared to ultraviolet. However only a fraction of this light can be absorbed by the active layer in a solar cell. If one can broaden the spectral range of sunlight that a solar panel can capture, the overall power generated increases. One strategy to increase the fraction of light absorbed is to combine two low-energy photons and fuse their energy into one higher-energy photon, a process called upconversion. The upconverted photon can then be absorbed and used to generate electricity from light that would otherwise be wasted. The goal of this project is to identify and design new molecules that can be used for upconversion in more efficient solar cells. Researchers will combine synthetic chemistry and optical characterization with theory and machine learning to achieve this goal. Beyond its scientific and technological impacts, participants will engage local and regional community college students with authentic and sustained exposure to original research experiences. One specific avenue the team is pursuing is to attempt to infuse photon upconversion research concepts into course-based academic laboratory experiments at a local community college. This approach to engage community college students with exposure to original research is intended to help overcome the geographic constraints that may hinder these students from taking part in more traditional research experience for undergraduate (REU) programs that require students to travel long distances to the research site.Technical DescriptionPhoton upconversion could significantly enhance solar cell efficiencies to routinely meet or exceed the Shockley-Queisser limit. One promising strategy for deploying photon upconversion to enhance the efficiency of solar photovoltaics is triplet-triplet annihilation upconversion because it can occur under low-intensity, non-coherent illumination from solar photons. Historically, the materials that have been explored for photon upconversion have included sensitizers based on precious metal complexes, arylhalides, and quantum dots. The first class is not economically viable due to the high cost of the metal, the second class is unstable under illumination, and the third class suffers from parasitic absorption of the upconverted light by the sensitizer. Given these materials constraints, the PI’s group identifies heavy-atom-free upconversion sensitizers based on thionated squaraine-based materials, which they explore as potential candidates for achieving NIR-to-visible photon upconversion for solar photovoltaic applications. The goal is to clarify elusive structure-function relationships that have historically made it challenging to identify NIR-absorbing triplet sensitizers in general, and more specifically, hitherto intractable to achieve NIR-to-Visible photon UC without using expensive precious metal centers or arylhalides that readily photodegrade, which are both unattractive for solar applications. One key goal of this work is to address specific questions such as, “What molecular descriptors are most prescriptive for simultaneously achieving NIR absorption and high intersystem crossing yields?” The team combines experimental and theoretical approaches based on ultrafast pump-probe spectroscopy, ab initio predictions, and reinforcement learning to identify and evaluate new molecular design strategies for materials that they synthesize and test in this project. The project also supports new Course-based Undergraduate Research Experiences (CUREs) for community college students to conduct advanced photonic materials research relevant for next-generation solar energy devices.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.

非技术描述高效、廉价地获取太阳能是生产清洁、可持续能源的重大挑战。太阳发出的光的光谱范围很广，从远红外到紫外线。然而，这种光只有一小部分能被太阳能电池的有源层吸收。如果能扩大太阳能电池板可以捕捉的太阳光的光谱范围，总发电量就会增加。增加光吸收比例的一种策略是将两个低能量的光子结合起来，并将它们的能量融合成一个更高能量的光子，这一过程被称为上转换。然后，上转换的光子可以被吸收，并被用来从本来会被浪费的光中产生电力。该项目的目标是识别和设计可用于更高效太阳能电池上转换的新分子。研究人员将把合成化学和光学表征与理论和机器学习结合起来，以实现这一目标。除了科学和技术影响之外，参与者还将让当地和地区的社区大学生真实和持续地接触到原创研究经验。该团队正在寻求的一个具体途径是尝试将光子上转换研究概念注入到当地社区大学基于课程的学术实验室实验中。这种让社区大学生接触原创研究的方法旨在帮助克服地理限制，这些限制可能会阻碍这些学生参加更传统的本科生研究体验(REU)项目，这些项目要求学生长途跋涉到研究地点。技术说明光子上转换可以显著提高太阳能电池的效率，通常达到或超过Shockley-Queisser限制。利用光子上转换来提高太阳能光伏发电效率的一个很有前途的策略是三重态-三重态湮没上转换，因为它可以在低强度、非相干的太阳光子照射下发生。从历史上看，被探索用于光子上转换的材料包括基于贵金属络合物、芳基卤化物和量子点的敏化剂。由于金属的高成本，第一类在经济上是不可行的，第二类在照明下不稳定，第三类遭受敏化剂对上转换光的寄生吸收。考虑到这些材料的限制，PI的团队确定了基于硫化方酸材料的无重原子上转换敏化剂，他们探索这些材料是实现太阳能光伏应用中近红外到可见光光子上转换的潜在候选者。我们的目标是澄清难以捉摸的结构-功能关系，这些关系历来使识别吸收近红外的三重态敏化剂具有挑战性，更具体地说，迄今为止难以实现从近红外到可见光的光子UC，而不使用昂贵的贵金属中心或容易光降解的芳基卤化物，这两种物质对太阳能应用都没有吸引力。这项工作的一个关键目标是解决一些具体的问题，例如“对于同时实现近红外吸收和高系统间交叉产量而言，什么分子描述符最具规范性？”该团队结合了基于超高速泵浦-探测光谱、从头预测和强化学习的实验和理论方法，为他们在该项目中合成和测试的材料识别和评估新的分子设计策略。该项目还支持社区大学生开展与下一代太阳能设备相关的高级光子材料研究的新课程本科生研究体验(CURE)。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。