Highly selective photonic glass filter for saturated blue structural color

Abstract

Angle independent non-absorbing spectral filters are required for many applications such as sunscreens, structural colors, photovoltaics, and radiative cooling. One of the promising and simple to manufacture structures is based on the disordered arrangement of monodisperse spherical particles by self-assembly, also called photonic glasses. So far, reported photonic glasses inherently show poor spectral selectivity with a smooth transition in reflection. No significant improvement is usually expected from particles optimization as the Mie resonances are broad for small dielectric particles with a moderate refractive index. Via Fourier space engineering, we show here that it is, nonetheless, possible to obtain sharp spectral transitions from the synergetic effect of a core-shell geometry of the particles with the short range order of the photonic glass. We apply the developed approach to demonstrate a high color saturation of a non-iridescent blue structural color employing a photonic glass with hollow sphere particles, which features a sharp spectral transition in reflection. The experimental results support the theoretical predictions from the first-order approximation.

Transparency induced in opals via nanometer thick conformal coating

“…The low reflection region also changes accordingly. The same effect was previously utilized by us to obtain highly saturated structural color in PhG 10,24 . However, the simulation reflection spectra (Fig.…”

YSZ Hollow Sphere Photonic Glasses: Tailoring Optical Properties for Highly Saturated Non‐Iridescent Structural Coloration

“…Based on this finding, we demonstrated in our recent work that hollow sphere PhGs with yttria‐stabilized zirconia (YSZ) shells can be used as for highly saturated non‐iridescent structural coloration where the improved saturation originates from the sharper reflection edge in the reflection spectrum in comparison to full sphere PhGs . As mentioned previously, non‐iridescent structural colors reported in the literature so far were mainly fabricated from polymer or silica spheres and are therefore limited regarding their application temperature.…”

“…However, it is important to note that results for the x and y values can differ depending on the measurement type and the film thickness. This is visualized by the black dot in Figure a,b which represents the same sample fabricated with 0.4 YSZ/PS ratio but in this case the reflection spectrum was obtain from a much smaller measurement area of 30 × 30 µm compared to 5 × 5 mm and in a region of lower film thickness of ≈ 2.0 µm (Figure S5, Supporting Information) . Deviations of the positions in the chromaticity diagram are therefore due to small thickness variations of the PhG films.…”

Influence of Alumina Addition on the Optical Properties and the Thermal Stability of Titania Thin Films and Inverse Opals Produced by Atomic Layer Deposition

“…Bio-inspired synthetic photonic crystals and glasses make use of this selectivity in the reflection of the spectrum, while expanding the spectral range to ultraviolet and infrared. Thus, applications not only as structural colors [ 2 , 3 , 4 , 5 , 6 ] but also as broadband reflectors [ 7 ], optical filters, thermal emitters for thermophotovoltaics [ 8 ], and in radiative cooling [ 9 , 10 ] are demonstrated. In a broader context, photonic crystals and glasses based on inversion of colloidal templates (also referred to as colloidal-based porous materials) can be used as sensors, membranes, self-cleaning surfaces, and in batteries and water purification systems [ 11 ].…”