Metamaterials operating at infrared (IR) frequencies have garnered significant attention due to the opportunities for resonant interactions with vibrational modes of molecules and materials and manipulation of thermal emission. These metamaterials usually consist of periodic arrangements of subwavelength scale metallic or dielectric elements, patterned either top-down by nanolithographic methods or bottom-up by nanocrystal (NC) assembly. However, conventional metals are inherently constrained by their fixed electron concentrations, which limits the degrees of freedom in the design of the meta-atom unit cells to achieve the desired optical response. In this context, doped metal oxide NCs, with the prototypical case being tin-doped indium oxide (ITO) NCs, are exceptional candidates for self-assembled IR metamaterials, owing to their relatively low and synthetically tunable electron concentrations that govern the frequencies of their IR plasmon resonances. Focusing on ITO NCs as building blocks, this Account describes recent progress in the synthetic tuning of NC optical properties, NC superlattice monolayer preparation methods for fabricating IR resonant metamaterials, and the emerging understanding of the optical response, facilitated by recently developed simulation methods.

中文翻译：

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等离子体金属氧化物纳米晶体作为红外超表面的构建块


由于与分子和材料的振动模式发生共振相互作用以及操纵热发射的机会，在红外 （IR） 频率下工作的超材料引起了广泛关注。这些超材料通常由亚波长级金属或介电元件的周期性排列组成，通过纳米光刻方法自上而下地形成图案，或通过纳米晶体 （NC） 组装自下而上形成图案。然而，传统金属本身受到其固定电子浓度的限制，这限制了超原子晶胞设计中的自由度，以实现所需的光学响应。在这种情况下，掺杂金属氧化物 NC，原型情况是掺锡氧化铟 （ITO） NC，是自组装 IR 超材料的绝佳候选者，因为它们的电子浓度相对较低且合成可调，控制着其 IR 等离子体共振的频率。本帐户侧重于 ITO NC 作为构建块，描述了 NC 光学特性的综合调整、用于制造 IR 谐振超材料的 NC 超晶格单层制备方法的最新进展，以及最近开发的仿真方法促进了对光学响应的新兴理解。