Enabling Nanomanufacturing via Fast Optical Nanopatterning

自上而下的纳米刻蚀是制造复杂几何形状的纳米结构的最有效方法，因此，通常是纳米制造的第一步。不幸的是，与模式复制相比，传统的纳米修饰方法极其缓慢。该奖项支持将大规模并行体系结构和一种新方法相结合的研究，这种方法允许光定义远远小于其他方法的纳米结构。其结果是实现了对小到大分子的结构的快速纳米化。当快速图案生成与快速图案复制(例如卷对卷纳米压印光刻)相结合时，出现了一种新的纳米制造范例。这种模式有可能实现全新的材料和器件功能，因为它提供了对纳米级结构的精细控制，并结合了对宏观区域的这种控制。当这项技术取得成果时，将使新类别的设备和应用成为可能，例如薄膜太阳能电池的捕光、大面积自清洁表面、抗微生物表面和大面积超材料(例如，隐形材料)。该奖项将提供基本的研究培训，利用多学科的专业知识，包括光学、化学、电气工程和材料科学。在这项研究中产生的基本知识将通过新的纳米喷雾技术的商业化得到广泛传播。远场衍射极限是将聚焦光束的大小限制在其波长的大约一半的基本物理屏障。当应用于具有可见光的纳米粒子时，这一限制可以防止产生小于~200 nm的结构。该项目将通过使用可以在两种同分异构体之间切换的光致变色分子来克服这一限制。通过将这种分子的单层暴露于空间变化的强度分布，首先形成两个异构体的化学模式。利用纳米级精度的步进工作台，基片相对于光学元件移动。第二次暴露在相同的照明下会触发光致变色分子。通过适当的阶段置换，与周围区域相比，可以留下分子的任意小区域(向下到单分子水平)，形成一种异构体形式。随后的锁定步骤可用于选择性地修饰该异构体，以使其不再是光致变色的。由于表面上的其他一切都是光致变色的，整个步骤序列可以重复，以“点阵”的方式创建任意复杂的几何图形。该奖项将支持设计、合成和表征合适的光致变色分子、新的光学系统和相关工艺的基础研究。

Top-down nanopatterning is the most effective approach for creating nanostructures of complex geometries and therefore, usually the first step in nanomanufacturing. Unfortunately, conventional approaches to nanopatterning are extremely slow compared to pattern replication. This award supports research that combines a massively parallel architecture and a new method that allows light to define nanostructures far smaller than is otherwise possible. The result is to achieve fast nanopatterning of structures as small as a large molecule. When fast pattern generation is combined with fast pattern replication (such as roll-to-roll nanoimprint lithography), a new paradigm for nanomanufacturing arises. This paradigm has the potential to enable entirely new material and device functionalities as it provides exquisite control of structure at the nanoscale in conjunction with such control over macroscopic areas. When brought to fruition, this technology will enable new classes of devices and applications, e.g., light-trapping for thin-film solar-cells, large-area self-cleaning surfaces, anti-microbial surfaces, and large-area metamaterials (e.g., cloaking materials). This award will provide essential training in research that draws upon expertise in multiple disciplines including optics, chemistry, electrical engineering and materials science. The fundamental knowledge generated during this research will be widely disseminated via the commercialization of the new nanopatterning technology. The far-field diffraction limit is a fundamental physical barrier that limits the size of a focused optical beam to approximately half its wavelength. When applied to nanopatterning with visible light, this limit prevents the generation of structures below ~200nm. This project will overcome this limit by using photochromic molecules that can be toggled between two isomeric forms. By exposing a monolayer of such molecules to a spatially varying intensity distribution, a chemical pattern of the two isomers is first formed. Using a stepping stage with nanometric precision, the substrate is then moved relative to the optics. A second exposure to the same illumination toggles the photochromic molecules. By appropriate displacement of the stage, it is possible to leave arbitrarily small regions of molecules (down to the single-molecule level) in one isomeric form compared to the surrounding region. A subsequent locking step may then be used to selectively modify this isomeric form such that it is no longer photochromic. Since everything else on the surface is photochromic, the entire sequence of steps can be repeated to create geometries of arbitrary complexity in a "dot-matrix" fashion. This award will support fundamental research into the design, synthesis and characterization of appropriate photochromic molecules, a new optical system, and related processes.