Diatom-Enabled Scalable Nanomanufacturing for Photonic Devices

硅藻作为微藻的主要类群，长期以来一直是许多研究领域的灵感和来源材料。丰富的纳米结构二氧化硅外骨骼（也称为晶体）的复杂形态已经引起了许多研究。迄今为止，硅藻小体已被用于荧光免疫分析，因为它们的纳米孔为生物分子的结合提供了大的表面积。由于其优异的光散射性能，它们也被用作染料敏化太阳能电池的阳极材料。硅藻体上的许多纳米结构具有明显的一致性，但它们很少用于可扩展的纳米图案制造。该奖项通过更好地了解硅藻晶体与其周围气体/液体/固体环境之间的相互作用，促进了如何大规模利用硅藻晶体纳米结构的知识。这种理解被用于生产大面积、均匀的硅藻结构组件，然后在二维和三维中复制它们的纳米结构。具体来说，研究了这些组件及其复制品的光子特性，并针对特定的光子应用进行了定制。该项目提供了一系列外联模块，旨在教育年轻的研究人员，包括妇女和代表性不足的少数民族，并培养他们对纳米科学和纳米制造技术的热情。硅藻是一种单细胞光合微藻，普遍存在于水生环境中，种类繁多，据估计现存种类达数万种。作为一种潜在的低成本生物材料，硅藻晶体包含密集的高度均匀的纳米孔阵列，其直径小至40-60纳米。为了充分利用这些非凡的纳米结构，硅藻支持的可扩展纳米制造方法在这项工作中进行了探索。典型的硅藻囊体形态（如Coscinodiscus sp.和Pinnularia sp.）被用来研究开发大面积囊体单层的不同策略。该项目解决了结晶体与液-气和液-固界面之间相互作用的基本和技术问题，并利用这些相互作用来实现均匀定向的致密结晶体单层，用于后续的纳米图案。通过分析这种相互作用的计算和实验结果，本研究试图通过优化晶壳表面处理和流体流动条件来优化硅藻单层组装的形成。在此基础上，通过表面微加工和微成型技术，研究了纳米图案转移技术在二维和三维结构复制中的应用。此外，还研究了结构体及其复制品的光散射特性。复制的纳米图案反映了晶体的分层纳米孔，专门用于光子应用，如红外吸收剂和光子晶体滤波器。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。

As a major group of microalgae, diatoms have long been the inspiration and source material in many research fields. The intricate morphology of the abundant nanostructured silicon dioxide exoskeletons (also known as frustules) have led to numerous studies. To date, diatom frustules have been used in fluorescence immunoassays because their nanopores provide large surface areas for the bonding of bio-molecules. They have also been used as anode materials in dye sensitized solar cells because of their excellent light scattering property. The numerous nanostructures on diatom frustules are markedly uniform, however, they are seldom used in the scalable manufacturing of nanopatterns. This award advances the knowledge of how to utilize diatom frustule nanostructures on a large scale, by developing a better understanding of the interaction between diatom frustules and their surrounding gas/liquid/solid environments. This understanding is harnessed to produce large-area, uniform diatom frustule assemblies, followed by the replication of their nanostructures in two- and three-dimensions. Specifically, the photonic properties of these assemblies and their replicas are investigated and tailored towards specific photonic applications. The project provides a series of outreach modules tailored towards educating young researchers, including women and underrepresented minorities, and for fostering their passion in nanoscience and nanomanufacturing technologies.Diatoms are unicellular photosynthetic microalgae which are ubiquitous in aquatic environments and remarkably diverse, with the estimated number of living species on the order of tens of thousands. As a potentially low-cost biomaterial, diatom frustules contain dense arrays of highly uniform nanopores, the diameters of which are as small as 40-60 nm. To fully utilize these remarkable nanostructures, diatom-enabled scalable nanomanufacturing approaches are explored in this work. Typical diatom frustule morphologies (e.g. Coscinodiscus sp. and Pinnularia sp.) are used to investigate different strategies in developing large-area frustule monolayers. This project addresses the fundamental and technological issues of the interactions between frustule and liquid-air and liquid-solid interfaces, and harnessing these interactions to achieve uniformly oriented compact frustule monolayers for subsequent nanopatterning. By analyzing computational and experimental results of such interactions, this research seeks to optimize diatom monolayer assembly formation through optimizing the frustule surface treatment and fluid flow conditions. Following the frustule assemblies, nanopattern transfer techniques are studied towards the 2D and 3D replication of frustule nanostructures through surface micromachining and micro-molding techniques. In addition, the light scattering properties of the frustule assemblies and their replicas are investigated. The replicated nanopatterns mirroring the hierarchical nanopores of the frustules are specifically tailored towards photonic applications, such as IR absorbers and photonic crystal filters.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.