Amorphous Photonic Crystals Research Articles

Rapid preparation of full color spectrum structural color coatings with iridescence effects via spray methods

Differing from conventional spray methods that only produce amorphous photonic crystals, this study innovatively achieves the ordered assembly of poly(styrene-methyl methacrylate-acrylic acid) (P(St-MMA-AA)) microspheres into photonic crystals on the substrate surface by adjusting the spray distance, a simple parameter. The resulting coating exhibits a uniform and iridescent structural color. Simultaneously, employing this technique, P(St-MMA-AA) microspheres with three different diameters (234 nm, 178 nm, and 152 nm) were mixed pairwise and co-organized in an ordered manner on the substrate surface. By adjusting the mass ratio of the two types of microspheres, structural color coatings covering the full visible spectrum were facilely and efficiently prepared. The coatings exhibit iridescence, and the structural colors are true colors with high color quality. Additionally, violet, unattainable in traditional color mixing systems, was achieved. The structural color coatings obtained in this study demonstrate promising applications in areas such as environmentally friendly finishes, optical anti-counterfeiting, and true-color displays.

Smart manufacturing of ZIF-8 photonic crystals: Catalytic formaldehyde degradation and colorful eco-friendly coatings

Formaldehyde and other harmful gases cause environmental pollution and threaten human health. Environment-friendly coatings is an effective strategy to address these environmental and health concerns. In this study, a large-scale amorphous photonic crystals (APC) based on modified ZIF-8 (Hxh-ZIF-8) with photocatalytic degradation of formaldehyde and tunable structural color were designed for eco-friendly coatings by programmable smart manufacturing. As APC unit, Hxh-ZIF-8 nanoparticles with controllable diameters were synthesized utilizing solvothermal method and the −N = C = O group was introduced with thermal oxidation. The results of photocatalytic degradation revealed that H5h-ZIF-8, through thermal oxidation, exhibited a formaldehyde degradation rate 9.8 times than that of ZIF-8. The main reactive components in photocatalysis were holes (h+) and superoxide radicals (·O2–), showcasing both stability and reproducibility. The color and brightness of the APC were adjusted by tuning the Hxh-ZIF-8 diameter. The angle-independent APC ranging from red to purple were fabricated with 177, 165 and 235 nm Hxh-ZIF-8 nanoparticles in various proportions with programmable smart manufacturing. In this study, a large-scale ZIF-8-based APC was designed with programmable smart manufacturing for environment-friendly coating, which combined environmental protection technology with structural color, and paved a new strategy for the development of multifunctional materials in air quality management.

Robust mechanical strength and high colorfastness of amorphous photonic crystals on fabrics with durable antibacterial and anti-static properties

The technique of utilizing structural color dyeing presents a sustainable and energy-conserving approach to textile dyeing. However, the coating with structural coloration always exhibited cracks and inadequate colorfastness attributed to the presence of capillary tension. In this study, we employed a hydrophilic silane called 3-aminopropyltriethoxysilane (KH550) to chemically modify the fabric. This method endowed the fabric with reactive amino groups, thereby augmenting the interfacial bonding strength between polydopamine (PDA)@SiO2@Ag+/Ag NPs and the fabric substrate through metal coordination and covalent bonds. Additionally, by utilizing catechol complexation, we successfully loaded Ag ions onto the PDA coating of composite microspheres. These Ag ions acted as linkers during self-assembly of microspheres. The active amino groups on the surface of chemically modified cotton fabric reacted with PDA at a specific temperature, resulting in the formation of robust covalent bonds simultaneously. The resulting fabric demonstrated excellent water resistance as well as efficient antibacterial and anti-static properties, which were confirmed through various mechanical tests such as washing, folding, and rubbing experiments. This research presents an innovative approach for creating durable structural colored fabrics with multifunctional properties based on metal coordination and covalent bonds that can be effectively applied in textile printing and dyeing.

High-efficiency fabrication of uniform photonic crystals by a vertical deposition method from multiple glass slides of simple moulds and their application in isomer recognitions

Vertical deposition method is a simple, cheap and common method for fabricating photonic crystals (PCs). However, a majority of PCs are obtained based on the traditional vertical deposition method from one glass slide, the method is low efficiency. Herein, it is proposed to efficiently fabricate uniform PCs by an optimized vertical deposition method from double or multiple glass slides of simple moulds. Amounts of SiO2 spheres, distances of two glass slides of moulds, preparation temperatures and different diameters of SiO2 spheres are investigated for obtaining uniform PCs. And different types of PCs (the bottom-middle-top 3D PCs, bilayer 2D PCs and amorphous PCs) are also fabricated based on the optimized vertical deposition method. The above method is a simple, cheap and high-efficiency way for mass production of uniform PCs. Meanwhile, the chemicals with similar refractive indices (isomers and cis-trans isomers) can be easily distinguished under high humidity based on dynamic reflection spectra of the PCs. For example, the difference in the refractive indices of m-xylene and p-xylene is only 0.002, the difference of desorption balance time of PCs is 263 s. The PCs have potential applications in visual detections, isomer recognitions and monitoring of volatilization rates of trace liquids.

Bio-inspired fabrication of non-iridescent structural color coatings with excellent colorfastness for rapid and large-scale colorization of textile

Structural color in nature provides a new strategy for eco-friendly colorization. Biomimetic construction of amorphous photonic crystals (APCs) on the substrate surface can form a specific non-iridescent structural color, which can be widely used in textile, paint and other fields. However, the APCs structural color has the shortcomings of dim color and poor colorfastness, which restrict the industrial application. In this study, base on the structural design of APCs building blocks, a novel copolymer containing reactive epoxy groups of poly (styrene-co-glycidyl methacrylate) (P(St-co-GMA)) was synthesized, which was used for fabricating APCs structural color by rapid spray coating method. P(St-co-GMA) nanospheres with different particle diameters can be self-assembled into APCs showing different crack-free structural colors. This research reports for the first time that the polymer nanospheres with two different particle diameters were synthesized by one-pot polymerization to enhance the color brightness of structural color. P(St-co-GMA) nanospheres structural colorized fabrics showed excellent colorfastness, flexibility and air permeability. This research promotes the industrial application of structural color for the rapid larger-scale fabrication of APCs with excellent colorfastness on substrates through the synthesis of polymer nanospheres with reactive epoxy groups.

Infiltration-assisted colloidal assembly of amorphous photonic crystal patterns with high color saturation and mechanical stability

Fabrication of a steady APC pattern with high color saturation and mechanical stability via the IFAST Mayer rod coating method.

Phase-separated Tenmoku “Blue” glaze: Microstructure and coloring mechanism

Yohen Tenmoku, a masterpiece of Jian kiln with bright blue rendering effect under different incident light, is lack research as only three intact pieces exist in the world. Herein, this study was fortunate to work with Sun Jianxing to conduct technical characterization and material analysis of the imitation Yohen Tenmoku (Song). Black oil spots are composed of magnetite (10-25 μm) and Al doping in hematite (1-3 μm) precipitated on the glaze surface. Brilliant blue color a combination of the bright blue structural color resulting from the coherent scattering of amorphous photonic crystals composed of spherical phase separation structures of 130 nm and the coloring of iron ions produced in a weak reducing atmosphere by the addition of high iron glazes with composite alkali (CaO and MgO). Continuous refraction and reflection of the structural color between the blue glass phases gives the glaze a shiny and dazzling blue color.

Highly Sensitive Detection of Isomers through Dynamic Reflection Spectroscopy Based on Simple Amorphous Photonic Crystals

Highly Sensitive Detection of Isomers through Dynamic Reflection Spectroscopy Based on Simple Amorphous Photonic Crystals

Angle-independent cellulosic photonic crystals for smart and sustainable colorimetric sensing

Cellulose nanocrystals, as well as hydroxypropyl cellulose, can form lyotropic liquid crystals, which can be processed into pigments or glitter products for sustainable coloration. Some stimuli-responsive polymers or nanoparticles are expected to form colorimetric sensors via co-assembly with these cellulosic photonic crystals. The co-assembly behavior of CNCs with polymers is determined by the hydrogen bonds and physical adsorption. Thus, adjusting the molecular chain structure, hydrophilicity, and electrostatic interaction of co-assembled polymers can lead to flexible and tunable colorimetric cellulosic sensors. Despite the advantages of cellulose-based amorphous photonic crystal (APC) pigments or glitters as sustainable and visually captivating sensors, there are still problems in efficient preparation and co-assembly conditions. This editorial will provide a brief discussion of the benefits, applications, and challenges of cellulose-based APCs.

Environment-friendly coating with good weather resistance prepared by amorphous photonic crystals and water-dispersible resin

Traditional coatings are fabricated from chemical colorants and oleoresinous resins. However, chemical colorants and organic solvents as diluents of oleoresinous resins are pollutant for environment. Herein, environment-friendly coatings with good weather resistance are proposed by using amorphous photonic crystals (APC) and water-dispersible resins. Monodispersed silica spheres are used for producing APC and structural color. And the water-dispersible epoxy resin has a good weather resistance property. After environment-friendly coatings are submerged in toluene, acidic solution (pH = 2) and alkaline solution (pH = 12) for 2040, 840 and 840 h, respectively, the coatings are still intact, and they do not fade. The environment-friendly coatings also are able to withstand the test of 336 h under ultraviolet light. The coatings have great potential applications in displays, decorations and automotive coatings.

Construction of amorphous photonic crystal coated fabrics with wash resistance and antifouling performance

Construction of amorphous photonic crystal coated fabrics with wash resistance and antifouling performance

Facile preparation of amorphous photonic structure towards rapid temperature sensing and antibacterial textile

A rapid temperature sensing device and antibacterial textiles were successfully developed based on amorphous photonic crystals with bright structural colors which were doped with silver nanoparticles to absorb incoherently scattered light.

Synthesis of SiO2@Ag for light absorption and the fabrication of highly color-saturated amorphous photonic crystals

A novel APC structural color film with excellent color visibility and color saturation is fabricated through the layer-by-layer self-assembly of SiO2@Ag and SiO2 microspheres.

Thermal vacuum de-oxygen fabrication of new catalytic pigments: SiO2@TiO2-x amorphous photonic crystals for formaldehyde removal.

Eliminating benzene and formaldehyde pollution is indispensable after the popularity of colorful home decoration in current society. The possibility and advantages of vividly colorful amorphous photonic crystals (APCs) as catalytic pigments were established. Biomimetic synthesis of APCs is an effective approach to obtaining angle-independent structural colors. Herein, we introduce oxygen vacancies through thermal vacuum de-oxygenation to synthesize SiO2@TiO2-x APCs for angle-independent structural colors and enhanced photocatalytic performance in one step. Core-shell nanospheres with controllable particle size were synthesized using a mixed-solvent method as the structural unit of APCs to prepare seven structural colors: red, orange, yellow, green, cyan, blue, and purple. The photocatalytic activity of in situ fabricated SiO2@TiO2-x APCs was conspicuously enhanced by thermal vacuum deoxidation. An amorphous layer formed on the TiO2 nanocrystals provides TiO2-x with excellent spectral response to visible light, transient photocurrent, and surface photovoltage up to 38.44 μA cm-2 and 28.8 mV, respectively. Black TiO2-x absorbs incoherent scattering, causing APCs to generate vividly angle-independent structural colors. The existence of oxygen vacancies in TiO2-x promotes electron activation and a synergistic effect with the photonic local effect of APCs in improving the degradation of formaldehyde by catalytic pigments, effectively protecting the beautiful living environment of human beings.

Bioinspired MXene-Based Soft Actuators Exhibiting Angle-Independent Structural Color

HighlightsDesign and fabrication of MXene-based soft actuators with angle-independent structural color.The nanostructured MXene can not only facilitate the formation of short-range ordered 3D amorphous photonic crystals, but also help significantly improve structural color saturation.The soft actuators exhibit brilliant angle-independent structural color, ultrafast actuation and recovery speeds in response to vapor.

Semitransparent Organic Solar Cells with Viewing‐Angle‐Independent Janus Structural Colors

AbstractSemitransparent organic solar cells (STOSCs) hold great promise for applications ranging from building‐integrated photovoltaics to portable electronic devices, yet often challenging over the realization of color tunability. The structural colors generated by microcavity, subwavelength grating, or photonic crystals are highly dependent on the viewing angle, which limits the application of STOSCs in real scenarios. Herein, the spectrally selective substrates consisting of silica spheres‐based amorphous photonic crystals (APCs) are proposed to unify the optical spectra of STOSCs at different viewing angles. By optimizing the periodicity of APCs, STOSCs exhibit viewing‐angle‐independent reflection with colors varying from blue to pink. The synergetic interplay between the reflection of APCs and the absorption of active layer results in the Janus optical effect that the transmitted light is fixed at blue regardless of the reflected color. The STOSCs on flexible plastic retain the stable color even at bending state. These results pave the way for the potential application of colorful solar photovoltaic glass curtains.

A smart large-scale explosive-responsive amorphous photonic crystal sensor based on color analysis method

Leveraging advances in nanoscience and intelligent technology to engineer large-scale and stimuli-response amorphous photonic crystals (APCs) for use in inexpensive and portable sensing system for the detection of explosives. Polymethyl methacrylate (PMMA) colloidal microspheres with uniform particle size and good mono-dispersion were used to prepare APCs by spraying method. The structural color of APCs was angle-independent and changed with different microspheres size. Meanwhile, a robotic arm was designed to achieve an automatic and large-scale preparation of APCs, and this more accurate and cost-effective method not only provides an automatic process for large-scale APCs pattern painting in chemical industry, but also gives chemical sensors an access to be smart devices in life. Then 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and cyclotetramethylenete-tranitramine (HMX) molecularly imprinted APCs (MIAPCs) were fabricated in the same way. The results showed that the response time of MIAPCs was 10 s, and the limit of detection was 0.01 mM with NaOH swollen. Specially, by using the more convenient HSB (Hue-Saturation-Brightness) and CIE (Commission Internationale de L’Eclairage) color analysis methods, combined with principal component analysis and pattern recognition methods, a sensor group with higher selectivity and sensitivity than a single sensor was constructed. A qualitative and semi-quantitative result was realized by responding to the changes of structural color before and after. Compared with traditional PhCs sensor, the APCs sensor has angle-independent structural color, which provides more accurate results and simplifies the detection based on the color analysis. This novel large-scale APCs sensor represents a potential of highly selective and real-time on-site visual explosive detection. In the meanwhile, the automatic APCs casting also offers chemical materials an access to combining with intelligent technology.

The Development of New Catalytic Pigments Based on SiO2 Amorphous Photonic Crystals via Adding of Dual-Functional Black TiO2-x Nanoparticles.

Biomimetic synthesis of amorphous photonic crystals (APCs) is an effective approach to obtaining non-iridescent structural colors. However, the structural colors of artificially prepared APCs are dim or even white due to the influence of incoherent scattering. In this paper, we present a novel method to combine APCs with black TiO2-x to construct a noniridescent structural color pigments with high visibility and photocatalytic activity. Due to the absorption of incoherently scattered light by black TiO2-x, the color saturation of structural colors has been significantly increased. In addition, the utilization rate of photogenic carriers was effectively enhanced by the slow light effect generated from the pseudoband gap of SiO2 APCs with TiO2-x absorbed full spectrum. The tone and color saturation of catalytic pigments is controlled by the diameter of SiO2 nanospheres and the ratio of TiO2-x nanoparticles, which provides a controllable application study in color-related fields as artwork, environmental coatings, and textiles.

Photonic Plasticines with Uniform Structural Colors, High Processability, and Self-Healing Properties.

Despite the vast variety of colloidal superstructures available in soft matter photonics, it remains challenging to balance the trade-off between their optical microstructures and material processability. By synergizing colloidal photonics and dynamic chemistry, a type of photonic "plasticine" with characteristics of uniform structural colors, high processability, and self-healing is demonstrated. Specifically, a boronate ester bond-based macromonomer is first prepared through complexation between the diols of polyvinyl alcohol and the boronic acid group of 3-(acrylamido) phenylboronic acid in the presence of concentrated silica colloids. Upon photopolymerization, the dynamic photonic plasticine is formed in situ as the result of the crosslinking of the boronate ester bonded networks. The randomly packed colloids inside the plasticine compose the amorphous photonic crystals, giving rise to angle-independent structural colors that would not compromise during subsequent processing steps; the reversible nature of the boronate ester bonds endows the plasticine with self-adaptable and self-healing properties. Further, the plasticine is also compatible with common shaping methods, that is, cutting, molding, and carving, and thus can be facilely processed into 3D structural colored objects, holding great potentials in fields such as bio-encoding, optical filters, anti-counterfeiting, etc.

Self-assembly of colloidal particles into amorphous photonic crystals

This review focuses on the introduction, fabrication, and applications of amorphous photonic crystals.