Dispersions of reduced tungsten oxide and tungsten bronze nanoparticles are known to show a remarkable absorption of near-infrared (NIR) light applicable to solar control filters for automotive and architectural windows. Origin of the NIR absorption has been investigated by analyzing dielectric constants of CsxWO3 (x = 0.15, 0.25, and 0.33) and WO2.72, and using Mie scattering theory. The optical analysis and Mie scattering theory analysis indicate that a localized surface plasmon resonance and polarons of localized electrons contribute alongside to the observed NIR absorption at different wavelengths.

Optical absorption and scattering behaviors of lanthanum hexaboride (LaB6) nanoparticulate dispersion coatings with various particle sizes have been investigated in the ultraviolet to near-infrared (NIR) wavelengths for application to solar control filters. Large characteristic near-infrared absorption is introduced as the decreased particle size falls into nanoscale, and its origin is discussed in terms of a localized surface plasmon resonance (LSPR) of conduction electrons. Optical constants of LaB6 have been measured and Mie scattering theory analysis was conducted. The theory was found to generally replicate the optical characteristics, and variations of absorbed and scattered wave fractions as well as the LSPR wavelength have been discussed with varying particle size. The absorption peaks are found as shaped narrower and located at shorter wavelength in theory than in experiment, which is suggested as ascribed mainly to the nonspherical distorted shape of LaB6 nanoparticles.

This paper presents single particle fluorescence spectroscopy of perylene nanocrystals coupled with AFM observation of their topographic shapes. The fluorescence spectra of individual nanocrystals confirmed clearly and precisely a blue-shift in the excimer emission maximum on the reduction of their volume. The result can be explained in terms of “lattice softening”, which makes intermolecular interaction weaker and modified the energy level of the excimer state in nanocrystal.