Three-dimensional nanoparticle (NP) assemblies show interesting optical responses that differ from naturally occurring materials, such as metals, oxides, and semiconductors. In this study, we investigate the optical response of thin films comprising Sn:In2O3 NPs (ITO NP films) based on the correlation between complex permittivity and infrared (IR) reflectance for solar-thermal shielding applications. IR ellipsometry measurements are conducted to clarify the presence of Lorentz resonances in plasmonic metamaterials. The Lorentz resonances are correlated to the electric field strength at interparticle gaps by varying the Sn dopant concentration, as confirmed using finite-difference time-domain (FDTD) simulations. High solar-thermal shielding performance was obtained owing to selective near-IR reflection based on strong Lorentz resonances as the ITO NP films were electrically polarizable but magnetically inactive. Thermal shielding efficiency was demonstrated via a comparison of the air temperature change in a simulated box used as a model house. Additionally, we demonstrate the significance of NP packing density on the enhancement of the near-IR reflectance. The role of interparticle spacing for high near-IR reflectance was revealed by comparing effective medium approximation analyses and FDTD simulations. This relationship was also demonstrated by the reduction of solar-thermal shielding performance when using aggregated ITO NPs. Our work confirmed that the control of complex permittivity in plasmonic metamaterials must be considered in the structural design of transparent and reflective materials for solar-thermal shielding applications.

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The increase in mechanical stress at the interface of the Li metal and solid electrolyte induces dendritic Li growth in all-solid-state Li batteries. We have demonstrate that the increasing stress in Li metal is significantly reduced by porous current collectors (PCCs). Here, we demonstrate the PCC with 3- dimensional pores prepared by sintering a mixture of micrometer-sized Ni spherical particles and polymethyl methacrylate spheres as a template of pores. The low-cost sintering method realized not only reduction of the preparation cost of PCCs, but high internal short circuit resistance comparable to the expensive PCCs with regularly arranged through-holes using electroforming methods

Ordered mesoporousA uw as prepared using double gyroid (cubic Ia-3d)m esoporous silica KIT-6 as at emplate. The Au frameworks were formed within the template via as eed-mediated growth process. Au nanoparticles were initially prepared as seeds within the mesopores, and subsequently,t hey were grown under mild andc ontrolled reducing conditions. The transmission electron micrographs and scanning electron micrographs of mesoporous Au after the removal of the template revealed the formation of mesoporous Au replicas. The small-angle X-ray scattering pattern of mesoporousA ur eveals that the obtained mesoporousA u has ac ubic I4 1 32 mesostructure, whichi sd ifferent from that of the originalt emplate, implying that Au was deposited within only one mesochannel of the two interconnected ones. The seed-mediated growth process is ak ey factor in the successful formation of orderedm esoporous Au using a mesoporouss ilica template. Our preparative methodc an serve as ag uide for furtherd evelopment of synthetic and materials chemistry of mesoporousAu.