Spray-assembly of thermoplasmonic nanoparticles: A speed-up fabrication strategy for energy-saving smart windows

Abstract

Smart windows for adaptive solar modulation have attracted considerable attention because of their broad prospects in energy-saving buildings. Herein, energy-saving smart windows are fabricated by the high-efficiency spray assembly of thermoplasmonic gold nanoparticles (Au NPs). First, the adsorption kinetics of the Au NPs in the spray assembly are investigated based on a pseudo-first-order kinetics equation, which exhibit a spray-pressure dependency. The amount of adsorbed Au NPs after spraying at 30 psi for 20 s is up to ∼80% the saturation adsorption amount, demonstrating the high-speed characteristic of the spray assembly. The spray-assembled Au NP coating, as a solar heating surface, is used to construct smart windows for adaptive solar modulation with the thermochromic poly(N-isopropylacrylamide) hydrogel. The obtained smart window shields 76.6% of the total solar irradiation in the range 300–2500 nm and allows 80.3% of the visible light to enter indoors before optical switching by the hydrogel ensures visual comfort. The cooling performance of the smart window is determined to be ∼13.9 °C by a model house test under a stimulated solar irradiation of 2.8 kW·m−2 (2.8 suns). Moreover, the fabrication method is suitable for flexible substrates to prepare bendable smart windows. This work provides a speed-up fabrication strategy for the large-scale manufacturing of energy-saving smart windows.