High-performance Color Research Articles

High-performance color and fluorescence switching of cotton fabrics via light-induced proton transfer strategy of spiropyran sulfonate molecule

Light-responsive color-switching materials have garnered persistent interest recently due to their passive response to external stimuli and manifestation of notable visual color variations. Nonetheless, their development into high-end products has been hindered by unsatisfactory overall performance, characterized by challenges such as the inability to combine color contrast and retention time, poor repeatability, and reliance on a single coloring mode. Herein, we present a negative photochromic cotton fabric (NPCF) capable of real-time dual output of optical signals (color change or fluorescence emission), featuring high color contrast and resolution, excellent reversibility, and facile multicolor printing. These attributes stem from the utilization of a unique photoinduced proton transfer (PPT) strategy exhibited by the designed and synthesized spiropyran sulfonate molecule (MC-NO2). Guided by this strategy, NPCF demonstrates significant color changes and fluorescence switching in a real-time and highly reversible manner, leveraging the remote non-contact and non-destructive nature of visible light. Moreover, direct blending of MC-NO2 with commercially available water-soluble non-stimuli-responsive dyes enables customization of various photosensitive color systems for straightforward multi-color printing, aligning well with the environmental principles of green printing. This study serves as a valuable reference for the advancement and design of diverse high-performance, switchable materials suitable for the production of high-end products.

DEVELOPMENT OF AN EFFICIENT OPTICAL MODEL FOR LEDS-BASED WHITE LIGHT SPECTRUM DESIGN APPLICATIONS

We have developed an efficient optical model for simulating the white light spectrum design with high color performance. The optical model began with experimental data collection, simulation with the mathematical model using Gaussian functions, and verifying the similarity between simulation and experiment. In application, the model is applied to study the effect of red light on the optical properties of the generated white light spectrum. The obtained results indicate that the established model is helpful for the solid-state lighting application to fabricate a light source that can emit white light with high optical performance.

Intermolecular interaction-controlled novel azo dyes for use in the high-performance color conversion layers of microdisplays

We synthesized four novel red azo dyes for use in a low-temperature-cured white organic light-emitting diode color conversion layer. The various substituents were introduced into the synthesized dyes to induce steric strain within the base compound for enhancing their solubility. All synthesized dyes exhibited excellent maximum absorption peaks at 521 nm, and AR4, in particular, displayed the highest molar absorptivity of 42 500. Via optimal mixing, the synthesized dyes were used to form red color resists for use in microdisplay color conversion layers. As a white backlight was applied to the optimized spin-coated films, the AR3 and AR4 films, with large dihedral angles between their substituents and diazonium planes, exhibited excellent color coordinates and transmittances, as intermolecular aggregation was inhibited. The color resists fabricated using the AR3 and AR4 dyes also displayed clear micropatterning results, confirming their high compatibility with low-temperature curing binders for use in future display production.

Composite color filters for wide color gamut and high optical efficiency liquid crystal displays

We propose a composite color filter to achieve the wide color gamut and high optical efficiency of liquid crystal display (LCD). The composite color filter comprises a multi-layer polarization interference filter (ML-PIF) and a color filter. Specifically, two crossed polarizers and four twisted nematic liquid crystal layers with alternating opposite twisted directions form the ML-PIF. The Jones matrix method provides the transmittance formula of the ML-PIF. In the experiment, we successfully fabricate the blue and green ML-PIFs samples using the temperature birefringence effect of liquid crystal. When composite color filters (ML-PIF with certain color filters) are used in LCD, this can successfully achieve a color gamut of 122.3% NTSC and an absolute optical efficiency improvement of 1.4%. Alternatively, the composite color filter can attain a color gamut similar to that of a high-performance color filter and an absolute optical efficiency improvement of 3.8%. This composite color filter presents a tremendous opportunity for achieving a wide color gamut and high optical efficiency.

Achieving a wide color gamut based on polarization interference filters in a liquid crystal display.

We propose two polarization interference filters (PIF1 and PIF2) used in the backlight unit of a liquid crystal display (LCD) to achieve a wide color gamut. Both PIF1 and PIF2 consist of two polarizers and two 720° super twisted nematic liquid crystal polymer (LCP) layers, where two polarizers are crossed in PIF1, and two polarizers are parallel in PIF2. The PIFs can eliminate unwanted cyan and yellow parts in the output spectrum, which can improve the color gamut of LCD. In our calculation, when the PIF1 is employed in the LCD with normal color filter and QD-LED backlight, the color gamut increases from 107.3% NTSC to 124.6% NTSC, which is 13.7% NTSC larger than that of the LCD with high-performance color filter. When the PIF2 is employed in the LCD with normal color filter and QD-LED backlight, the color gamut of LCD with a normal color filter is improved by 6.8% NTSC larger than that of LCD with high-performance color film, and the transfer efficiency is close to that of the LCD with high-performance color film. We define the color gamut enhancement ratio (CGER) to compare the influence of PIFs and the high-performance color filter on the color gamut enhancement performance of LCD. Compared with the high-performance color filter, the two kinds of PIFs have a higher CGER. The PIFs have a great potential for achieving a wide color gamut.

Liquid crystal-powered Mie resonators for electrically tunable photorealistic color gradients and dark blacks

Taking inspiration from beautiful colors in nature, structural colors produced from nanostructured metasurfaces have shown great promise as a platform for bright, highly saturated, and high-resolution colors. Both plasmonic and dielectric materials have been employed to produce static colors that fulfil the required criteria for high-performance color printing, however, for practical applications in dynamic situations, a form of tunability is desirable. Combinations of the additive color palette of red, green, and blue enable the expression of further colors beyond the three primary colors, while the simultaneous intensity modulation allows access to the full color gamut. Here, we demonstrate an electrically tunable metasurface that can represent saturated red, green, and blue pixels that can be dynamically and continuously controlled between on and off states using liquid crystals. We use this to experimentally realize ultrahigh-resolution color printing, active multicolor cryptographic applications, and tunable pixels toward high-performance full-color reflective displays.

Dynamic Color Display with Viewing-Angle Tolerance Based on the Responsive Asymmetric Fabry-Perot Cavity.

At present, it remains challenging and desirable to prepare dynamic color-changing materials with wide viewing angles for practical applications. Herein, we proposed a responsive asymmetric metal-insulator-metal (MIM) Fabry-Perot resonance cavity to achieve dynamic color display with high viewing-angle tolerance. The responsive asymmetric MIM cavity is constructed with thermal-responsive poly(N-isopropyl acrylamide) (PNIPAm) brush as the mid-insulator layer sandwiched by two different metallic layers (Sn and Ag). The as-prepared MIM cavity shows both improved viewing-angle tolerance owing to the asymmetric architecture of the cavity and a wide tunable color gamut because of the thermal responsiveness of the mid PNIPAm layer. Remarkably, the as-prepared asymmetric MIM resonance cavity also possesses a relatively fast response rate and good repeatability. Together, with all these advantages, the proposed responsive asymmetric MIM cavity may open a new pathway to prepare high-performance color display material for future practical optical applications.

Synthesis and chromatic properties of high color performance Prx-ZrSiO4 (x = 0–0.1) yellow pigment

In this paper, high color performance Pr cation doped zircon (Pr-ZrSiO4) yellow pigment has been prepared by inorganic sol-gel method. Meanwhile, the detailed process parameters for preparation of Pr-ZrSiO4 pigment were systematically investigated. The research results indicate that the optimal process parameters are Pr-doping amount of 6 mol.%, calcination temperature of 900 °C, holding time of 2 h and Si/Zr ratio of 1.05. The synthesized Pr-ZrSiO4 pigment shows an intense yellow hue, which chromatic parameters are L* = 81.84, a* = 4.36, b* = 70.55 and C* = 70.68. Moreover, the pigment shows outstanding tinting performance for ceramic glaze, suggesting its attractive application in ceramic decoration. XPS analysis demonstrated that the Pr cations in the Pr-ZrSiO4 pigment consists of two valence states, namely trivalent and tetravalent. Finally, heterogeneously distributed behavior of Pr cations in the pigment was discovered.

10.1: Invited Paper: High Uniformity High Color Performance AMOLED Display in Mobile Phone Application

With the resolution and PPI increasing trend of AMOLED, high uniformity high color performance displays face great challenges. For high resolution and larger size, the color and brightness uniformity will get worse. In this paper, a method is proposed to improve brightness and color uniformity, therefore, the high quality picture display is achieved.

Synthesis of high color performance V-ZrSiO4 blue pigment with low doping amount via inorganic sol–gel route

In this paper, high color performance vanadium ion (V4+) doped ZrSiO4 (V-ZrSiO4) blue pigment with low doping amount has been successfully synthesized by inorganic sol–gel route. According to the phase evolution and color behavior of the samples, the formation mechanism of the V-ZrSiO4 pigment was revealed. Besides, due to the immobilization effect of the gel network and the high precursor reactivity, the reported synthesis route has extremely high vanadium utilization ratio (99.69%). Based on the results of XPS and XRF analysis, it is found that the valence state of vanadium ion in the V-ZrSiO4 pigment is 4+, meanwhile, the vanadium cations are heterogeneously distributed in the pigment particles and are enriched within the outer layers. Compared with the previously reported V-ZrSiO4 pigments, the as-prepared V-ZrSiO4 pigment shows a bright blue hue (b*=–22.01), in which the theoretical content of V4+ is only 2 mol%. After applying on ceramic glaze, the V-ZrSiO4 pigment exhibited superior coloring performance and high-temperature stability, indicating its potential application in ceramic decoration. This work provides a facile strategy to synthesize high color performance ion-doping type pigment.

Bias-Modulated Multicolor Discrimination Enabled By Perovskite Photodetector with Back-to-Back Diode Configuration

Photodetectors that convert incoming photons into electrical signals play a key role in wide emerging technologies, such as imaging, optical communication, bio-sensing, and environmental monitoring systems. Most conventional photo-detecting systems consist of broadband photodetectors and dissipative optical filters for measuring not only the brightness of illuminated light but also its spectral information. However, the integration of filters on top of the pre-fabricated detectors requires time-consuming and sophisticated alignment steps, consequently increasing the device cost. In addition, a considerable light loss caused by the filter (> 2/3 of the incident light) deteriorates the sensitivity of entire systems, particularly fatal in a relatively dark environment. Therefore, it is imperative to develop filter-free photodetectors (FFPs) with high sensitivity and specificity (narrow spectral response).Very recently, organic/inorganic perovskites have been intensively studied and exploited as promising FFPs due to the outstanding optoelectronic properties of perovskites (e.g., high extinction coefficients, small exciton binding energies, long exciton diffusion lengths, and optical gap tuneability). Perovskite FFPs appear to be quite effective in achieving not only a narrow-band spectral response with full-width at half-maximum values < 100 nm but also sufficient external quantum efficiencies of 10-200%. However, the FFPs consisting of a single perovskite absorber are limited to a specific spectral response, which is not suitable for the discrimination of multi-colors. In particular, to mimic photoreceptors in the retina of the human eye, at least three individual FFPs with different light absorbers (i.e., for red (R), green (G), and blue (B) light) are necessary for the discrimination of the visible light spectrum. Therefore, the design of a single FFP with multi-spectral responses would be highly beneficial for creating an integrated and high-performance color imaging system.Herein, we demonstrate, for the first time, a perovskite FFP adopting a back-to-back diode (p-i-n-i-p) configuration, in which a low-band n-i-p perovskite diode is vertically stacked on top of a high-band p-i-n perovskite diode. The unique device structure enables multi-spectral responses in the visible range through bias modulation. When a specific voltage is applied to the contact electrodes, one perovskite diode becomes active as a light absorber, while the other diode is inactive, and vice versa in the opposite voltage; thus, the FFP with the p-i-n-i-p configuration allows selective charge extraction from each perovskite by switching the bias polarity. This unique operation based on the two different perovskites can discriminate monochromatic RGB colors by a single device with a notably superior detectivity (> 1012 cm Hz1/2 W-1) to those of other conventional FFPs. In addition, we succeeded in discriminating mixed-color light using two p-i-n-i-p perovskite FFPs, which is more space- and cost-efficient than the conventional imaging system with three different dissipative color filters. Figure 1

Toward Full‐Color Tunable Chiroptical Electrothermochromic Devices Based on a Supramolecular Chiral Photonic Material

AbstractTraditional electrochromic devices change the color of electrochromic materials by mainly transforming the absorption band of the materials electrically, which leads to low schedulable color selection and color performance of such materials after electrochromism. Although the addition of an interference‐enhanced nanocavity can improve this issue, achieving full‐color controllability on a single electrochromic device is still a huge challenge. This study first demonstrates a near‐full‐color tunable chiroptical electrothermochromic device using a supramolecular chiral photonic material called ferroelectric liquid crystal (FLC)‐doped cholesteric liquid crystal (CLC) (FLC‐CLC). Experimental results show that the pitch of the CLC can be elongated significantly by doping a low concentration of FLC (≈4 wt%) such that the photonic bandgap (PBG) redshifts from blue to the shortwave near‐infrared region at near room temperature. Based on this fascinating feature, the PBG of the FLC‐CLC can be tuned electrically over the entire visible region with high color performance at near room temperature in a low‐voltage range (≤3 V) via the efficient electrothermal effect of the indium‐tin‐oxide‐coated substrate of the sample. Two potential low‐voltage tunable applications based on electrothermochromic FLC‐CLC materials, namely, a broadband tunable laser and a near‐full‐color tunable coaxial microfibric textile, are demonstrated in the study.

Urea-free reactive printing of viscose fabric with high color performance for cleaner production

Urea-free reactive printing has gained popularity as part of cleaner production in the textile printing industry. Printing additives containing little to no nitrogen are being explored as substitutes for urea. In this study, the hygroscopicity, ability to swell fibers, and ability to solubilize reactive dyes of various additives were compared to explore the intrinsic connections between the structures and the above-mentioned properties. The hydrogen-bond interactions between the reactive dye and additives were characterized by 1H NMR and DSC. Additives with good hygroscopic, swelling, and solubilizing properties were selected for their potential application in urea-free reactive deep printing on viscose fabric. Results showed that among various kinds of additives, glycerol had the best hygroscopicity, 1,4-butanediol had the best ability to swell viscose fibers, and the amides had the best ability to solubilize reactive turquoise K-GL. Hygroscopicity was considered as the most important factor, followed by the ability to swell fibers. When the mixed ratio of glycerol and 1,4-butanediol was 5:5, the color performances of the binary nitrogen-free compound were higher than those of a commercial alternative. Its printing performances came close to those of urea, exhibiting great potential as a substitute for urea. Nitrogen-free alternatives will remarkably reduce the ammonia–nitrogen pollutants emitted into the environment by the reactive printing process.

Supramolecularly Engineered J-Aggregates Based on Perylene Bisimide Dyes.

The discovery of the self-assembly of cyanine dyes into J-aggregates had a major impact on the development of dye chemistry due to the emergence of new useful properties in the aggregated state. The unique optical features of these J-aggregates are narrowed, bathochromically shifted absorption bands with almost resonant fluorescence with an increased radiative rate that results from the coherently coupled molecular transition dipoles arranged in a slip-stacked fashion. Because of their desirable properties, J-aggregates gained popularity in the field of functional materials and enabled the efficient photosensitization of silver halide grains in color photography. However, despite a good theoretical understanding of structure-property relationships by the molecular exciton model, further examples of J-aggregates remained scarce for a long time as supramolecular designs to guide the formation of dye aggregates into the required slip-stacked arrangement were lacking.Drawing inspiration from the bacteriochlorophyll c self-organization found in the chlorosomal light-harvesting antennas of green sulfur bacteria, we envisioned the use of nature's supramolecular blueprint to develop J-aggregates of perylene bisimides (PBIs). This class of materials is applied in high-performance color pigments and as n-type organic semiconductors in transistors and solar cells. Combining outstanding photochemical and thermal stability, high tinctorial strength and excellent fluorescence, PBIs are therefore an ideal model system for the preparation of J-aggregates with a wide range of potential applications.In this Account, we elucidate how a combination of steric constraints and hydrogen bonding receptor sites can guide the self-assembly of PBI dyes into slip-stacked packing motifs with J-type exciton coupling. We will discuss the supramolecular polymerization of multiple hydrogen-bonded PBI strands in organic and aqueous media and how minor structural modifications in monomeric PBI molecules can be used to obtain near-infrared absorbing J-aggregates, organogels, or thermoresponsive hydrogels. Pushing the boundaries of self-assembly into the bulk, engineering of the substituents' steric requirements by a dendron-wedge approach afforded adjustable numbers of helical strands of PBI J-aggregates in the columnar liquid-crystalline state and the preparation of lamellar phases. To fully explore their potential, we have studied PBI J-aggregates in collaborative work with spectroscopists, physicists, and theoreticians. In this way, exciton migration over distances of up to 180 nm was shown, and insights into the influence of static disorder on the transport of excitation energy in PBI J-aggregates were derived. Furthermore, the application of PBI J-aggregates as functional materials was demonstrated in photonic microcavities, thin-film transistors, and organic solar cells.

High-Performance and Low-Power Full Color Reflective LCD for New Applications

High-Performance and Low-Power Full Color Reflective LCD for New Applications

High-Performance and Low-Power Full Color Reflective LCD for New Applications

High-Performance and Low-Power Full Color Reflective LCD for New Applications

Protease and sodium alginate combined treatment of wool fabric for enhancing inkjet printing performance of reactive dyes

Usually, it is difficult to achieve high performance images on original wool fabrics due to the presence of scales on the fiber surfaces. Herein, we developed a novel and environmental combined process with a protease enzyme and sodium alginate for wool fabric inkjet printing using reactive dyes. The results indicate that the protease and SA combined treatment of wool fabrics produced high color performance of printed fabrics with the deepest, brightest and finest color effect. FESEM, XPS and wettability analysis reveal that most of the wool scales were eliminated by the protease and the SA formed uniform and compact films on the newly created fiber surfaces with more hydrophilicity of 70.1° contact angle and 3.5 s wetting time. The protease-SA treated wool fabrics exhibit satisfactory washing and rubbing fastness and acceptable strengths. This process has the advantages of zero AOX emission, low strength loss and satisfactory color fastness.

Synthesis and coloration of highly dispersive SiO2/BiVO4 hybrid pigments with low cost and high NIR reflectance

Highly dispersed SiO2/BiVO4 hybrid pigments with a spherical structure and high near-infrared (NIR) reflectance have been successfully fabricated by a facile sol–gel method followed by calcination. The dispersed and uniformly spherical particles of the hybrid pigments were caused by the support provided by SiO2 microspheres, and their color was adjusted via the band-gap energy, which was changed with the incorporation of SiO2 microspheres. The SiO2/BiVO4-3 hybrid pigment presented higher yellow hues (b* = 91.42) and more dispersed spherical particles than other as-prepared hybrid pigments and commercially available BiVO4-based yellow pigment. This strategy could save 72 wt% resource of BiVO4 while yielding the same amount of yellow pigment with high color performance. Therefore, the prepared hybrid pigments not only dramatically decreased the cost of expensive pigments, but also saved scarce resources and reduced environmental pollution. In addition, the SiO2/BiVO4-3 hybrid pigment also presented high NIR reflective performance, which demonstrated that it would be a favorable candidate for colorful NIR reflective pigments with wide applications in heat insulation.

High-performance color sequence particle streak velocimetry for 3D airflow measurement.

In this paper, a high-performance color sequence particle streak velocimetry (CSPSV) technique is proposed to measure the air velocity in a large three-dimensional (3D) space. Based on the basic principle of CSPSV, a new color sequence illumination pattern is designed to mark seeding bubbles for better imaging performance. Synchronized with the illumination system, cameras record the targets' paths at the start, middle, and end points with different color information more clearly. Thus, a rectification-based stereo corresponding algorithm is presented to reconstruct the 3D trajectory of the bubbles. The accuracy of this system is verified and shows good consistency with a hot-wire anemometer (the principal research tool for turbulent-flow studies). The vortex test experiments also indicate its capability for complex airflow. Our high-performance CSPSV can extend the 3D measurement zone from several cubic centimeters to several cubic meters with regular, off-the-shelf cameras.

Development of High-performance Color Materials Using Organo-catalyzed Controlled Radical Polymerization

Development of High-performance Color Materials Using Organo-catalyzed Controlled Radical Polymerization