Nanophotonics‐enabled smart windows, buildings and wearables

Abstract

Design and production of spectrally smart windows, walls, roofs and fabrics has a long history, which includes early examples of applied nanophotonics. Evolving nanoscience has a special role to play as it provides the means to improve the functionality of these everyday materials. Improvement in the quality of human experience in any location at any time of year is the goal. Energy savings, thermal and visual comfort indoors and outdoors, visual experience, air quality and better health are all made possible by materials, whose "smartness" is aimed at designed responses to environmental energy flows. The spectral and angle of incidence responses of these nanomaterials must thus take account of the spectral and directional aspects of solar energy and of atmospheric thermal radiation plus the visible and color sensitivity of the human eye. The structures required may use resonant absorption, multilayer stacks, optical anisotropy and scattering to achieve their functionality. These structures are, in turn, constructed out of particles, columns, ultrathin layers, voids, wires, pure and doped oxides, metals, polymers or transparent conductors (TCs). The need to cater for wavelengths stretching from 0.3 to 35 µm including ultraviolet-visible, near-infrared (IR) and thermal or Planck radiation, with a spectrally and directionally complex atmosphere, and both being dynamic, means that hierarchical and graded nanostructures often feature. Nature has evolved to deal with the same energy flows, so biomimicry is sometimes a useful guide.

Reflection of near-infrared light confers thermal protection in birds

“…Our results suggest that birds, and potentially other animals, may have solved the problem of competing selection for optical and thermal functions by modulating visible and NIR properties differently. Mimicking those solutions in developing artificial materials to enhance energy efficiency holds significant promise 27 , 28 . Our data also highlight that empirical measures of NIR reflectivity must be incorporated into mechanistic models predicting the effects of climate change, particularly extreme heat events, on individual fitness and species distributions.…”

Reflection of near-infrared light confers thermal protection in birds

“…Our results suggest that birds, and potentially other animals, may have solved the problem of competing selection for optical and thermal functions by modulating visible and NIR properties differently. Mimicking those solutions in developing artificial materials to enhance energy efficiency holds significant promise 27 , 28 . Our data also highlight that empirical measures of NIR reflectivity must be incorporated into mechanistic models predicting the effects of climate change, particularly extreme heat events, on individual fitness and species distributions.…”

A Study of the Optical Properties and Fabrication of Coatings Made of Three-Dimensional Photonic Glass

“…Non-iridescent photonic glass with various colors was obtained. This type of color coating has wide potential applications, including in reflective displays [31], colorimetric sensors [32], textiles [33], and buildings [34].…”

Climate is a strong predictor of near-infrared reflectance but a poor predictor of colour in butterflies

“…The application of calibrated NIR imaging may reveal unappreciated variation in reflectance properties and novel thermal adaptations. As butterflies are important models for bioinspired nanophotonic materials [75,81,82], characterizing NIR reflectance properties could inform the development of new functional materials, such as coatings for passive radiative cooling and improved solar energy-capture technology [75,83,84].…”

Reflection of near-infrared light confers thermal protection in birds

“…Our results suggest that birds, and potentially other animals, may have solved the problem of competing selection for optical and thermal functions by modulating visible and NIR properties differently. Mimicking those solutions in developing artificial materials to enhance energy efficiency holds significant promise 27 , 28 . Our data also highlight that empirical measures of NIR reflectivity must be incorporated into mechanistic models predicting the effects of climate change, particularly extreme heat events, on individual fitness and species distributions.…”

A Study of the Optical Properties and Fabrication of Coatings Made of Three-Dimensional Photonic Glass

“…Non-iridescent photonic glass with various colors was obtained. This type of color coating has wide potential applications, including in reflective displays [31], colorimetric sensors [32], textiles [33], and buildings [34].…”

Climate is a strong predictor of near-infrared reflectance but a poor predictor of colour in butterflies

“…The application of calibrated NIR imaging may reveal unappreciated variation in reflectance properties and novel thermal adaptations. As butterflies are important models for bioinspired nanophotonic materials [75,81,82], characterizing NIR reflectance properties could inform the development of new functional materials, such as coatings for passive radiative cooling and improved solar energy-capture technology [75,83,84].…”

Reflection of near-infrared light confers thermal protection in birds

“…Our results suggest that birds, and potentially other animals, may have solved the problem of competing selection for optical and thermal functions by modulating visible and NIR properties differently. Mimicking those solutions in developing artificial materials to enhance energy efficiency holds significant promise 27 , 28 . Our data also highlight that empirical measures of NIR reflectivity must be incorporated into mechanistic models predicting the effects of climate change, particularly extreme heat events, on individual fitness and species distributions.…”

A Study of the Optical Properties and Fabrication of Coatings Made of Three-Dimensional Photonic Glass

“…Non-iridescent photonic glass with various colors was obtained. This type of color coating has wide potential applications, including in reflective displays [31], colorimetric sensors [32], textiles [33], and buildings [34].…”

Climate is a strong predictor of near-infrared reflectance but a poor predictor of colour in butterflies

“…The application of calibrated NIR imaging may reveal unappreciated variation in reflectance properties and novel thermal adaptations. As butterflies are important models for bioinspired nanophotonic materials [75,81,82], characterizing NIR reflectance properties could inform the development of new functional materials, such as coatings for passive radiative cooling and improved solar energy-capture technology [75,83,84].…”