Effects of Integrated Carbon as a Light Absorber on the Coloration of Photonic Crystal-Based Pigments

Abstract

Three-dimensionally ordered macroporous (3DOM) materials prepared by colloidal crystal templating are examples of photonic crystals that can exhibit structural color. The color intensity can vary widely, from a pale, nearly white opalescence to vivid, brilliantly metallic colors. Such variations are observed even for 3DOM materials of a single nominal composition that exhibit virtually identical structural order in scanning electron micrographs and are prepared from the same colloidal crystal templates. In this study we investigate the cause of the variations in color intensity for 3DOM ZrO 2 systems, considering both the role of zirconia grains in the skeleton of the photonic crystal and the presence or absence of carbonaceous components in the material. Such components act as broad spectral light absorbers and are introduced either directly in the synthesis through the precursor and the polymeric template or by postsynthesis addition and carbonization of sucrose solutions. We conclude that grain-size effects do not play a significant role but that the carbon content in 3DOM ZrO 2 provides direct control over the intensity of structural color in these photonic pigment materials.

Inverse Opal SiO2 Photonic Crystals as Structurally‐Colored Pigments with Additive Primary Colors

“…[17] For colored 3DOM materials, it has been shown that a lightabsorbing substance within the structure greatly enhances the color intensity through the absorption of incoherently scattered light. [18] A similar enhancement of color intensities through the use of carbon nanoparticles infiltrated into opaline materials has also been observed. [19] For 3DOM materials, however, this absorber species can be created in situ during thermal processing and does not require additional integration steps.…”

“…Building on recent advances that demonstrated the benefit of including carbon within the 3DOM oxide structure, [18] we employed pyrolysis in an inert gas atmosphere to maintain small levels of carbon that originated from decompo- Table 1. Structural and optical parameters for blue, green, and red 3DOM SiO 2 after grinding through a 38-μm sieve.…”

“…Carbon as an absorber species is produced by incomplete combustion of decomposition products from the polymer template and/ or precursor material, especially if heated in an inert atmosphere, or it can be added after the synthesis of the 3DOM materials. [18] In this study, we synthesized 3DOM SiO 2 in various colors for use as photonic pigments. SiO 2 was chosen because of its non-toxicity, relative abundance, high chemical stability, ease of synthesis, and ability to be functionalized with other surface groups if needed.…”

Hierarchical structural control of visual properties in self-assembled photonic-plasmonic pigments

“…Engineering structural colors, originating from wavelength-selective scattering rather than absorption, has long been used in conjunction with molecular absorbers to produce visual effects in pigments (e.g. sparkle, color travel) [4][5][6][7][8][9][10][11][12][13][14]. Structural color is achieved by controlling the shape, layering, roughness or porosity of materials on length scales ranging from hundreds of nanometers up to millimeters [12,[15][16][17][18][19].…”

“…While the manufacturing of versatile structural color materials requires exquisite control of fabrication parameters on multiple length scales, it is decoupled from the specifics of the material chemistry or composition. Thus, in contrast to molecular dyes, a multitude of structural color effects can be generated from a single inert material [4][5][6][7][8][9][10][11][12][13][14].…”