Understanding Emerging Photon Avalanching Processes in Lanthanide-Based Nanomaterials

在化学系大分子、超分子和纳米化学（MSN）项目的支持下，哥伦比亚大学的P. James Schuck教授正在研究镧系元素纳米颗粒中的光子雪崩行为。 当纳米粒子吸收一种颜色的光时，它们通常会发出另一种颜色的光，这一过程称为光致发光。在大多数情况下，光致发光的强度与激发光的强度成比例。光线加倍，光致发光的亮度也加倍。然而，情况并非总是如此。有时光的吸收可以使纳米颗粒更容易吸收更多的光。在这些情况下，当激发光的强度加倍时，光致发光的亮度将增加一倍以上。这种特性被称为光子雪崩，它可以用于各种新兴的应用。 然而，只有少数物质表现出光子雪崩行为，关于这种不寻常的性质还有很多东西要了解。舒克教授和他的学生将使用实验和理论相结合的方法来解开关于是什么控制这些独特纳米结构中的光子雪崩的基本见解。他们的发现可能会影响从高效的上转换激光器和图像处理到红外量子计数，固态照明和宽带光子学等技术，所有这些技术都依赖于快速和节能的光材料相互作用。该项目还将促进STEM教育，通过突出化学和工程学科之间非传统联系的研究和教学活动，吸引研究生、本科生和代表性不足的高中生。该项目旨在通过结合先进表征、理论建模、精密合成和分层纳米粒子设计的协同努力，从根本上理解和开发新的雪崩纳米粒子。雪崩纳米粒子将使用单粒子成像和光学光谱方法进行研究，揭示关键的机械参数和定义，并最终限制，在这类新材料的光子雪崩响应的基本环节。此外，将开发纳米粒子中光子雪崩的改进模型，使不同的能量转移（ET）过程和重组途径的作用的定量推导-和预测纳米化学依赖的雪崩特性-结合我们的实验测量。该研究有望为光子雪崩纳米结构领域的快速发展建立基础科学和战略，具有超灵敏成像，光捕获和紧凑量子光子学的潜力。该奖项反映了NSF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。

With support from the Macromolecular, Supramolecular, and Nanochemistry (MSN) program in the Division of Chemistry, Professor P. James Schuck of Columbia University is studying the photon avalanching behavior in lanthanide-based nanoparticles. When nanoparticles absorb light of one color, they often emit light of another color, in a process known as photoluminescence. In most cases, the intensity of the photoluminescence scales with the intensity of the exciting light. Double the light and photoluminescence is twice as bright. However, that is not always the case. Sometimes the absorption of light can make a nanoparticle more likely to absorb more light. In these cases, the brightness of the photoluminescence would more than double when the intensity of the exciting light doubles. This property is known as photon avalanching, and it could be used in a variety of emerging applications. However, there are only a few examples of substances that exhibit photon avalanching behavior and much remains to be learned about this unusual property. Professor Schuck and his students will use a combined experimental and theoretical approach to unlock fundamental insights about what controls the photon avalanching in these unique nanostructures. Their discoveries could impact technologies ranging from efficient upconverting lasers and image processing to infrared quantum counting, solid-state lighting and broadband photonics, all of which rely on rapid and energy efficient light-material interactions. The project will also promote STEM education, engaging graduate, undergraduate, and underrepresented high school students through research and teaching activities highlighting non-traditional links between chemistry and engineering disciplines.This project aims to fundamentally understand and develop new avalanching nanoparticles through a synergistic effort that combines advanced characterization, theoretical modeling, precision synthesis and hierarchical nanoparticle design. Avalanching nanoparticles will be investigated using single-particle imaging and optical spectroscopy approaches, revealing critical mechanistic parameters and essential links that define, and ultimately limit, the photon avalanching response in this new class of materials. In addition, improved models of photon avalanching in nanoparticles will be developed, enabling the quantitative derivation of the roles of distinct energy transfer (ET) processes and recombination pathways – and the prediction of nanochemistry-dependent avalanching properties – when combined with our experimental measurements. The research is expected to establish foundational science and strategies for jump-starting the field of photon avalanching nanostructures, with potential for ultrasensitive imaging, light harvesting, and compact quantum photonics.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.