Design of Bioinspired Ordered Materials for Spectral Modulation

Conspectus Spectral modulation, the precise control over light reflection, transmission, absorption, and scattering, has become a transformative approach in areas such as smart windows, adaptive camouflage, radiative cooling, anticounterfeiting, and photovoltaics. Typical strategies primarily rely on tuning the intrinsic properties of electrochromic, thermochromic, or photochromic materials. Yet, these material-driven approaches still suffer from limited color purity, narrow tunability, slow response, and poor multifunction integration. An emerging alternative is to treat structural order as an independent physical design dimension. By organizing nanoscale building blocks into periodic, hierarchical, or reconfigurable architectures, one can manipulate light through Bragg diffraction, Mie scattering, plasmonic resonance, and graded-index effects. These mechanisms are difficult to access by chemical composition alone. Nature provides a rich library of such ordered designs. Photonic crystals, multilayers, porous networks, and graded-index arrays in organisms achieve efficient reflection, absorption, and transmission under ambient conditions. These biological systems show that precise control over orientation, periodicity, layer spacing, and refractive-index contrast can produce optical functions far beyond those of homogeneous materials. Translating these biological blueprints into synthetic stimuli-responsive systems offers a route from static structural control to dynamic and intelligent spectral regulation. In this Account, we describe our efforts along a three-stage trajec…