Zhang Haibin, Guan Chunlin, Song Ning, Zhang Yuanyuan, Liu Hong, Fang Jingzhong
Lightweight Optics and Advanced Materials Center, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu, 610209, China.
Phys Chem Chem Phys. 2018 Jan 31;20(5):3571-3580. doi: 10.1039/c7cp07112d.
Herein, we present an effective bottom-up strategy to fabricate unprecedented macroscopic two-dimensional (2D) plasmonic gold superlattices composed of high-index faceted gold nanocrystal building blocks (NBBs) at the air-liquid interface. In this approach, a synergistic electrostatic and layered self-assembly technique was executed using unique icosidodecahedral gold nanocrystals. It showed that centimeter-squared areas of close-packed monolayer films were formed, and the interparticle spacing of neighbouring Au NBBs could be facilely manipulated from hundreds to several nanometers. Optical characterization demonstrated that particular plasmonic coupling could occur and enhance in a wide spectral range (visible and near-IR) as the self-assembled Au superlattices were tuned for an appropriate gap distance and specific NBB size; however, the orientation of individual NBBs remained somewhat unorganized. Thus, the well pronounced shift of localized surface plasmon resonances (LSPR) and the in-depth resonance splitting behaviors were presented in our investigations. Furthermore, corresponding electromagnetic simulations showed good agreement with the experimental results; this indicated that a new class of tunable coupled plasmonic Au superlattices was realized. This study complements the insights into the plasmonic coupling of layered Au superlattices and enables the colloidal self-assembly to extend to unconventional NBBs; thus, it may facilitate the design of novel plasmonic metamaterials or other superstructures for desired functionalities and applications in the future.
在此，我们展示了一种有效的自下而上策略，用于在气液界面制备由高折射率刻面金纳米晶体构建块（NBBs）组成的前所未有的宏观二维（2D）等离子体金超晶格。在这种方法中，使用独特的icosidodecahedral金纳米晶体执行了协同静电和分层自组装技术。结果表明，形成了平方厘米面积的紧密堆积单层膜，相邻金NBBs的粒子间距可以很容易地从数百纳米调节到几纳米。光学表征表明，随着自组装金超晶格被调整到合适的间隙距离和特定的NBB尺寸，特定的等离子体耦合可以在宽光谱范围（可见光和近红外）内发生并增强；然而，单个NBBs的取向仍然有些无序。因此，在我们的研究中呈现了局域表面等离子体共振（LSPR）的明显位移和深入的共振分裂行为。此外，相应的电磁模拟与实验结果显示出良好的一致性；这表明实现了一类新型的可调谐耦合等离子体金超晶格。这项研究补充了对分层金超晶格等离子体耦合的认识，并使胶体自组装能够扩展到非常规的NBBs；因此，它可能有助于未来设计具有所需功能和应用的新型等离子体超材料或其他超结构。
