Dynamic light-scattering metamaterial for smart window application

In-situ composite electrodeposition integrating electrochromic materials with light-scattering structures. • Tungsten-oxide-based dynamic light-scattering metamaterial achieved by modulating deposition kinetics. • On-demand control of diffuse transmittance via voltage application. • Color variation matches visual thermal perception. Glass curtain walls and windows provide a typical solution for architectural daylighting design. However, normal glass materials fail to resolve the contradiction between daylighting and overheating, along with glare and privacy issues, especially in regions characterized by long sunshine hours, high irradiance intensity and arid climate. In this work, we introduce an in-situ composite electrodeposition strategy to regulate the micro-nanostructure of tungsten oxide, enabling the first preparation of tungsten-oxide-based light-scattering metamaterial with dynamically modulating diffuse transmittance through varying applied voltages. Its color variation aligns with visual thermal perception, demonstrating excellent visual-aesthetic properties. The maximum haze of metamaterial is 82.9%. The metamaterial exhibits a visible-light diffuse transmittance of 63.8% at 604 nm, and a total transmittance as high as 82.4% at 580 nm (in the bleached state). More importantly, the metamaterial exhibits excellent cycling stability, retaining 85.1% of its initial transmittance modulation at 633 nm after 4000 cycles. Thermal management test shows that the metamaterial can reduce indoor temperature by up to 11.8 °C versus normal glass. EnergyPlus simulations show that up to 49.4 MJ/m 2 of energy can be saved annually in Santiago with intense solar irradiance. The dynamic scattering metamaterial we have developed offers a sustainable and highly energy-efficient innovative solution for green building applications in regions abundant in solar resources.