IRES Track 1: Self-assembled liquids and thin films for efficient photon upconversion with triplet excitons in air

这个IRES的科学目标是更好地理解空气稳定，光子上转换薄膜或液体的制造，这些薄膜或液体可以在漫射阳光下有效地工作，而不需要目前限制实际应用的挥发性有机溶剂。在九州大学度过四到八周的时间，完全沉浸在日本社会中，这将为你提供体验和了解日本人民、传统和文化的机会。美国学生将从这种国际合作中获得的文化和科学接触将是无价的。九州大学是日本排名最高的大学之一，福冈这个国际化大都市非常欢迎外国人。这个机会有望提高参与STEM工作的学生的全球竞争力，并将通过广泛接触加州州立大学系统、加州大学系统和参加专业会议的学生，例如美国化学学会和材料研究学会，向合格的美国学生提供，特别是那些在科学和工程领域代表性不足的学生。在这项国际合作中，每年将有四名美国本科生和/或研究生参与者在加利福尼亚和日本进行基于三重态聚变的光子上转换的基础研究。具有三重态特征的分子激发态的聚变是直接上转换来自太阳的光子的唯一方法。虽然在挥发性有机溶剂中已经证明了这些高光子上转换量子产率，但由于三重态激子扩散不良，它们通常在薄膜中较低。美国学生将合成和制造半导体纳米晶体的液体或薄膜，以及在各种宿主（包括蛋白质、有机凝胶和表面活性剂）中组织的分子发射器，以了解和控制光生三重态激子的扩散。本项目旨在利用半导体纳米晶体强吸收近红外波长的光，以解决分子三重态光敏剂的主要限制之一。杂化纳米材料将被设计成阻止分子发射体的自发结晶与亚硝基交联化学；在共价有机框架中增加三元态在液体或薄膜中的扩散长度，并建立氧屏障以防止自旋三重态激子猝灭。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。

The scientific goal of this IRES is to gain better understanding for the fabrication of air-stable, photon upconversion thin films or liquids that can operate efficiently with diffuse sunlight, without the need of volatile organic solvents that currently limit practical use in applications. Complete immersion in Japanese society by spending four to eight weeks in Kyushu University will provide an opportunity to experience and understand the people, traditions and culture. The cultural and scientific exposure that the U.S. students will obtain from this international collaboration will be invaluable. Kyushu University is one of the top-ranked universities in Japan, and the cosmopolitan metropolis of Fukuoka is welcoming to foreigners. This opportunity is expected to enhance the global competitiveness of the participating students in the STEM workforce, and will be made available to qualified U.S. students, especially those underrepresented in science and engineering, by broadly reaching out to the California State university system, the Univ. of California system, and students attending professional conferences organized for example, by the American Chemical Society and Materials Research Society.In this international collaboration, four U.S. undergraduate and/ or graduate participants per year will perform fundamental research on triplet-fusion based photon upconversion both in California and Japan. The fusion of molecular excited states with triplet character is the only method for directly upconverting photons from the sun. While these high photon upconversion quantum yields have been demonstrated in volatile organic solvents, they are generally lower in thin film due to poor triplet exciton diffusion. The U.S. students will be synthesizing and fabricating liquid or thin-films of semiconductor nanocrystals and molecular emitters organized in various hosts, including proteins, organogels and surfactants, to understand and control the diffusion of photogenerated triplet excitons. This project aims to use semiconductor nanocrystals to absorb light strongly in the near-infrared wavelengths to address one of the major limitations in molecular triplet photosensitizers. The hybrid nanomaterials will be designed to halt the spontaneous crystallization of the molecular emitter with nitrene crosslinking chemistry; increase triplet diffusion lengths in liquids or thin films with long-range order in covalent organic frameworks and establish a barrier to oxygen to prevent the quenching of spin-triplet excitons.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.