NaYeoun Kim, Ji-Hyeok Huh, YongDeok Cho, Sung Hun Park, Hyeon Ho Kim, Kyung Hun Rho, Jaewon Lee, Seungwoo Lee
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引用次数: 0
Abstract
This study demonstrates the developments of self-assembled optical metasurfaces to overcome inherent limitations in polarization density (P) and high refractive indices (n) within naturally occurring materials. The Maxwellian macroscopic description establishes a link between P and n, revealing a static limit in natural materials, restricting n to ≈4.0 at optical frequencies. Previously, it is accepted that self-assembly enables the creation of nanogaps between metallic nanoparticles (NPs), boosting capacitive enhancement of P and resultant exceptionally high n at optical frequencies. The work focuses on assembling gold (Au) NPs into a closely packed monolayer by rationally designing the polymeric ligand to balance attractive and repulsive forces, in that polymeric brush-mediated self-assembly of the close-packed Au NP monolayer is robustly achieved over a large-area. The resulting monolayer of Au nanospheres (NSs), nanooctahedras (NOs), and nanocubes (NCs) exhibits high macroscopic integrity and crystallinity, sufficiently enough for pushing n to record-high regimes. The systematic comparisons between each differently shaped Au NP monolayers elucidate the significance of capacitive coupling in achieving an unnaturally high n. The achieved n of 10.12 at optical frequencies stands as a benchmark, highlighting the potential of polyhedral Au NPs in advancing optical metasurfaces.
本研究展示了自组装光学元表面的发展,以克服天然材料在偏振密度(P)和高折射率(n)方面的固有限制。麦克斯韦宏观描述建立了 P 和 n 之间的联系,揭示了天然材料中的静态限制,在光学频率下将 n 限制在≈4.0。在此之前,人们认为自组装能够在金属纳米粒子(NPs)之间产生纳米间隙,从而提高 P 的电容增强效应,并在光学频率下产生极高的 n。这项研究的重点是通过合理设计聚合物配体来平衡吸引力和排斥力,从而将金(Au)纳米粒子组装成紧密堆积的单层,在大面积范围内实现聚合物刷介导的紧密堆积金纳米粒子单层的自组装。由此产生的金纳米球(NSs)、纳米八面体(NOs)和纳米立方体(NCs)单层具有很高的宏观完整性和结晶性,足以将 n 推向创纪录的高水平。通过对每种不同形状的金氧化物单层进行系统比较,阐明了电容耦合在实现非自然高 n 方面的重要作用。在光学频率下实现的 10.12 n 是一个基准,凸显了多面体金氧化物在推动光学元表面发展方面的潜力。
期刊介绍:
Small serves as an exceptional platform for both experimental and theoretical studies in fundamental and applied interdisciplinary research at the nano- and microscale. The journal offers a compelling mix of peer-reviewed Research Articles, Reviews, Perspectives, and Comments.
With a remarkable 2022 Journal Impact Factor of 13.3 (Journal Citation Reports from Clarivate Analytics, 2023), Small remains among the top multidisciplinary journals, covering a wide range of topics at the interface of materials science, chemistry, physics, engineering, medicine, and biology.
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