Spectrally selective coatings of gold nanorods on architectural glass

Abstract

Infrared-blocking coatings on window glass can be produced by dispersing gold nanorods into a polymer coating.The spectral-selectivity of the coating is controlled by the shape and aspect ratio of the nanoparticles, which are in turn determined by the conditions applied during their synthesis. Coatings of nanorods in polyvinyl alcohol were deposited onto glass and characterized in both laboratory and sun-lit conditions. Selective attenuation of the nearinfrared was demonstrated with the test panels transmitting approximately one third of the incident solar radiation, and absorbing nearly two thirds. The high absorptive cross-sections of the gold nanorods suggests that they can be applied in efficacious coatings at relatively low volume fractions.

Efficient NIR light blockage with matrix embedded silver nanoprism thin films for energy saving window coating

“…The FOM measured here is comparable to the FOM reported for gold nanorods (AuNRs) in PVA (1.000-1.030) where AuNRs were mixed into 15 wt% PVA solutions in various ratios, 14 but is lower than for films prepared with LaB 6 nanoparticles (FOM 1.705-1.934, 0.02-0.03% NP loading). 12 However, two considerations should be taken into account: firstly the reported films are 0.8 mm thick, and secondly different polymer matrices were used.…”

“…The ideal value of the FOM would be 2.08, corresponding to a material absorbing all the NIR radiation while passing all UV and visible light, but usually values above 1 are aimed at. 14 The FOM values (Table 1 and Fig. S4, ESI ‡) are higher for the (SNP-2)@SiO 2 /PMMA than for the (SNP-1)@SiO 2 /PMMA composites, with higher loading of SNP leading to a reduction of the FOM due to higher absorbance in the visible region.…”

“…Reporting good figures of merit (FOM) in terms of the ratio between the visible and the solar transmitted light (T lum and T sol ), the LaB 6 particles outperform ITO based systems. NIR absorbing gold nanorods dispersed in a PVA matrix have recently been employed for window coatings by Stokes et al 14 These coatings absorb the NIR radiation up to 60% and show a good T lum of around 40%.…”

Formation of Gold Nanorods by a Stochastic “Popcorn” Mechanism

“…old nanorods have strongly anisotropic optical properties, which suggest diverse technological applications. [1][2][3][4][5] The rods exhibit optical absorption peaks arising from surface plasmon resonances in the longitudinal as well as transverse directions. The resonances can be tuned to absorb light with wavelengths ranging from 520 to more than 1600 nm by control of the aspect ratio (the length / diameter ratio) of the rods.…”

Nanophotonics-enabled smart windows, buildings and wearables

“…They can strengthen, shift and extend the width of scattering peaks or act as antireflecting outer layer to enhance absorption or transmission in the resonant nanostructures below. Doping oxides, polymers or polymer layers with noble metal nanoparticles is a common way to achieve sharp plasmonic resonance at visible and, for some shapes, near-IR wavelengths [66][67][68]. Nevertheless, these are not well suited for use in building windows and skylights for reasons of durability and cost, and because they often reduce light input.…”