Cholesteric liquid crystals(CLCs)exhibit unique helical superstructures that selectively reflect circularly polarized light,enabling them to dynamically respond to environmental changes with tunable structural colors....Cholesteric liquid crystals(CLCs)exhibit unique helical superstructures that selectively reflect circularly polarized light,enabling them to dynamically respond to environmental changes with tunable structural colors.This dynamic color-changing capability is crucial for applications that require adaptable optical properties,positioning CLCs as key materials in advanced photonic technologies.This review focuses on the mechanisms of dynamic color tuning in CLCs across various forms,including small molecules,cholesteric liquid crystal elastomers(CLCEs),and cholesteric liquid crystal networks(CLCNs),and emphasizes the distinct responsive coloration each structure provides.Key developments in photochromic mechanisms based on azobenzene,dithienylethene,and molecular motor switches,are discussed for their roles in enhancing the stability and tuning range of CLCs.We examine the color-changing behaviors of CLCEs under mechanical stimuli and CLCNs under swelling,highlighting the advantages of each form.Following this,applications of dynamic color-tuning CLCs in information encryption,adaptive camouflage,and smart sensing technologies are explored.The review concludes with an outlook on current challenges and future directions in CLC research,particularly in biomimetic systems and dynamic photonic devices,aiming to broaden their functional applications and impact.展开更多
Dynamic structuralcolors can change in response todifferent environmental stimuli.This ability remains effectiveeven when the size of the speciesresponsible for the structural coloris reduced to a few micrometers,prov...Dynamic structuralcolors can change in response todifferent environmental stimuli.This ability remains effectiveeven when the size of the speciesresponsible for the structural coloris reduced to a few micrometers,providing a promising sensingmechanism for solving microenvironmentalsensing problems inmicro-robotics and microfluidics.However, the lack of dynamicstructural colors that can encoderapidly, easily integrate, and accuratelyreflect changes in physical quantities hinders their use in microscale sensing applications. Herein, we present a 2.5-dimensionaldynamic structural color based on nanogratings of heterogeneous materials, which were obtained by interweaving a pH-responsive hydrogelwith an IP-L photoresist. Transverse gratings printed with pH-responsive hydrogels elongated the period of longitudinal grating in the swollenstate, resulting in pH-tuned structural colors at a 45° incidence. Moreover, the patterned encoding and array printing of dynamic structuralcolors were achieved using grayscale stripe images to accurately encode the periods and heights of the nanogrid structures. Overall, dynamicstructural color networks exhibit promising potential for applications in information encryption and in situ sensing for microfluidic chips.展开更多
Inspired by special color-forming organisms in nature,photonic crystal materials with structural color function have been developed significantly with great potential applications for displays,sensors,anti-counterfeit...Inspired by special color-forming organisms in nature,photonic crystal materials with structural color function have been developed significantly with great potential applications for displays,sensors,anti-counterfeiting inks,etc.This review aims to summarize the functions,self-assembly modes,and ap-plications of different kinds of photonic crystal materials.The preparation methods and characteristics of monodisperse inorganic nanoparticles,polymer nanoparticles,inorganic/organic core-shell nanoparti-cles,and MOFs are discussed.Subsequently,we summarize the method of assembling colloidal parti-cles into photonic crystals,which is a template induction method,inkjet printing method,drop coating method,etc.Moreover,the potential application of structural color is presented including humidity re-sponse and magnetic field response in sensors fields,as well as the advantages and disadvantages of anti-counterfeiting,fabric coloring,displays,smart windows,and Biomedical Applications.Finally,we present the development prospects and key problems of photonic crystals.展开更多
Soft actuators have garnered substantial attention in current years in view of their potential appliances in diverse domains like robotics,biomedical devices,and biomimetic systems.These actuators mimic the natural mo...Soft actuators have garnered substantial attention in current years in view of their potential appliances in diverse domains like robotics,biomedical devices,and biomimetic systems.These actuators mimic the natural movements of living organisms,aiming to attain enhanced flexibility,adaptability,and versatility.On the other hand,angle-independent structural color has been achieved through innovative design strategies and engineering approaches.By carefully controlling the size,shape,and arrangement of nanostructures,researchers have been able to create materials exhibiting consistent colors regardless of the viewing angle.One promising class of materials that holds great potential for bioinspired soft actuators is MXenes in view of their exceptional mechanical,electrical,and optical properties.The integration of MXenes for bioinspired soft actuators with angle-independent structural color offers exciting possibilities.Overcoming material compatibility issues,improving color reproducibility,scalability,durability,power supply efficiency,and cost-effectiveness will play vital roles in advancing these technologies.This perspective appraises the development of bioinspired MXene-centered soft actuators with angleindependent structural color in soft robotics.展开更多
Structural colors with high saturation,large gamut,high resolution,and tunable color are expected in practical applications.This work explores the generation of tunable structural color based on transmission metasurfa...Structural colors with high saturation,large gamut,high resolution,and tunable color are expected in practical applications.This work explores the generation of tunable structural color based on transmission metasurfaces.The designed metasurfaces consist of rectangular nanoholes etched in silver film,which is deposited on the stretchable polydimethylsiloxane(PDMS)substrate.The smaller separation of adjacent nanoholes makes the resolution of metasurface reach 63,500 dpi.The color gamut of the nanostructures reaches 146.9%sRGB.We also perform a comparison with the case on the glass substrate and analyze the incident polarization condition and the coating film of polymethyl methacrylate(PMMA).The ultra-thin structure,high resolution,highperformance structural colors,and convenient transmission mode provide broad application prospects for metasurfaces in color displaying,color printing,and color holographic imaging.展开更多
Structural colors have always attracted much attention due to important applications in display devices,imaging security certification,optical data storage,and so on.The brightness of structure colors,as the carrier o...Structural colors have always attracted much attention due to important applications in display devices,imaging security certification,optical data storage,and so on.The brightness of structure colors,as the carrier of chiaroscuro information,is the key to making images appear stronger in the spatial and three-dimensional sense.However,relatively little work has been done on the control of the color brightness,and the reported structures are complex and difficult to fabricate.Here,we demonstrate a low-aspect-ratio anisotropic metasurface consisting of a PMMA film patterned by arrays of elliptical-shaped holes clamped by two thin aluminum films.By utilizing localized surface plasmon resonances,we realize a three-dimensional(3D)HSB(hue,saturation,and brightness)structure color with independent brightness control and enhance the cross-polarization reflection,covering approximately 120%of the s RGB color gamut.It is shown that the ratio of the major and minor axes leads to the independent control of brightness of the structural colors.The nanoprinting of HSB images with smooth brightness transitions is demonstrated through elaborate design of the metasurface geometry parameters and CMOScompatible micro-nano fabrication process.Our findings will facilitate the broad range of 3D nanoprinting and modern advanced display applications.展开更多
We experimentally demonstrate ultrafast laser-writing wide-gamut structural colors on TiAlN thin film that is coated on TiN substrate via laser-induced surface oxidation.The experiments involve thorough control over l...We experimentally demonstrate ultrafast laser-writing wide-gamut structural colors on TiAlN thin film that is coated on TiN substrate via laser-induced surface oxidation.The experiments involve thorough control over laser parameters,including powers,scanning speeds and pulse durations,to investigate the interplay between these variables and the resulting structural colors.Surface characterization techniques,such as scanning electron microscopy,energy-dispersive x-ray spectroscopy and atomic force microscopy,are employed to analyze the properties of laser-induced oxide layers and their chromatic responses.Our findings indicate that while laser powers and scanning speeds are critical in determining the irradiated dose and the subsequent coloring effects,the pulse duration exerts a distinct influence,particularly at low laser powers as well as slow scanning speeds.Longer pulse durations are found to produce a more significant coloring change despite exhibiting lower oxygen content.This is attributed to the increased surface roughness and deeper oxidation layer achieved with prolonged pulses.We propose two oxidation mechanisms–photo-oxidation and thermal-oxidation–to elucidate the influence of pulse duration on laser coloring effects.These findings not only refine existing paradigms in laser-induced surface coloration but also stimulate further exploration of structural colors’multifaceted applications across diverse technological contexts.展开更多
Through millennia of evolution,some organisms can change colors rapidly for camouflage,communication,attraction,and warning to adapt to the dynamic environment.By mimicking the dynamic coloration strategies of natural...Through millennia of evolution,some organisms can change colors rapidly for camouflage,communication,attraction,and warning to adapt to the dynamic environment.By mimicking the dynamic coloration strategies of natural organisms,artificial materials with responsive structural colors have emerged as promising candidates due to their environmental friendliness,real-time responsiveness to stimuli,and wide color gamut.These materials have attracted immense interest in anti-counterfeiting,displays,sensing,and smart actuators.This paper aims to present a survey on the response mechanisms,color modulation strategies,and applications of the structural color materials that are developed from different principles,such as photonic crystals(PCs),liquid crystals(LCs),and metasurfaces.We first discussed various structural color materials and their colorization mechanisms.We then classified these materials according to their color regulation strategies,such as responsiveness to physical,chemical,and biological stimuli.Subsequently,we provided a comprehensive overview of their applications for anti-counterfeiting,display technologies,sensing devices and detection platforms,and the biomedical field.Finally,we discuss the future prospects of responsive structural color materials and the issues that need to be addressed for their improvement.This review not only summarizes modulation strategies for dynamic structural colors but also provides valuable references and insights for future research in the field of structural coloration.展开更多
Structural color materials,which generate colors through the interaction between light and nano-microstructures,have always been research hotspots in the fields of display,anticounterfeiting and stimuli-responsive mat...Structural color materials,which generate colors through the interaction between light and nano-microstructures,have always been research hotspots in the fields of display,anticounterfeiting and stimuli-responsive materials.Structural colors based on scattering have received increasing attention due to their wider viewing angles than that originating from the specular reflection of photonic crystals.However,the wide scattering spectrum of an amorphous structure leads to lower purity and brightness of the appeared colors.Few researchers have focused on the scattering of ordered structures due to their strong reflection and diffraction in the visible regions.In this work,by building ordered films(OFs)using SiO2 spheres(refractive index n=1.46)with a diameter of 300–500 nm,for the first time,sharp scattering spectra with narrow full width at half-maximum(FWHM,24 nm)were generated.Importantly,under ambient light,brilliant colors covering the entire visible region can be observed,and a formula was proposed to calculate the scattering spectra of OFs.Moreover,rainbow structural color was realized under irradiation of the nonparallel light,and full-spectrum structural color patterns were fabricated using building blocks with a single particle size by a spraying method.Finally,a composite structure was constructed to explore possibilities in the field of flexible transparent displays.展开更多
Structural colors have drawn wide attention for their potential as a future printing technology for various applications,ranging from biomimetic tissues to adaptive camouflage materials.However,an efficient approach t...Structural colors have drawn wide attention for their potential as a future printing technology for various applications,ranging from biomimetic tissues to adaptive camouflage materials.However,an efficient approach to realize robust colors with a scalable fabrication technique is still lacking,hampering the realization of practical applications with this platform.Here,we develop a new approach based on large-scale network metamaterials that combine dealloyed subwavelength structures at the nanoscale with lossless,ultra-thin dielectric coatings.By using theory and experiments,we show how subwavelength dielectric coatings control a mechanism of resonant light coupling with epsilon-near-zero regions generated in the metallic network,generating the formation of saturated structural colors that cover a wide portion of the spectrum.Ellipsometry measurements support the efficient observation of these colors,even at angles of 70°.The network-like architecture of these nanomaterials allows for high mechanical resistance,which is quantified in a series of nano-scratch tests.With such remarkable properties,these metastructures represent a robust design technology for real-world,large-scale commercial applications.展开更多
Recently, the Fano resonance has played an increasingly important role in improving the color performance of structural colors. In this study, we further elucidate the asymmetric spectral shape generated by Fano reson...Recently, the Fano resonance has played an increasingly important role in improving the color performance of structural colors. In this study, we further elucidate the asymmetric spectral shape generated by Fano resonance from a phase perspective and explore four distinct continuum state structures. By integrating the proposed cavity-like structure with a metal±dielectric±metal discrete state, multilayered thin-film structural colors with minimal background reflection, as low as 8%, were successfully achieved. The reflection peak of this structure exhibits a bandwidth of approximately50 nm and reaches up to 80%, indicating heightened saturation and color brightness. Moreover, by adjusting the thickness,we effortlessly obtained a broader color gamut compared to Adobe RGB (45.2%), covering 56.7% of the CIE color space. Even adjusting a single layer can achieve a color gamut of 47.1%. In experiments, by deliberately choosing low oxygendependent materials, excellent RGB colors with high brightness and in high consistency with simulation results were successfully achieved. Therefore, the scheme's simple process for structural color creation, along with its excellent color performance and the ability to effectively replicate simulation characteristics makes it highly valuable in fields like anticounterfeiting, decoration, display devices, and solar cell panels.展开更多
Wenhao Wang and colleagues summarized the latest advancements in structural color research in Opto-Electronic Science. Their review explored the fundamental principles and fabrication methods of structural colors for ...Wenhao Wang and colleagues summarized the latest advancements in structural color research in Opto-Electronic Science. Their review explored the fundamental principles and fabrication methods of structural colors for photonic applications, including anti-counterfeiting, displays, sensors, and printing, along with their practical limitations. Recently, structural colors have received growing interest due to their advantages, including physical and chemical robustness, ecofriendliness, tunability, and high-resolution color.展开更多
Printing stable color with a lithography-free and environment-friendly technique is in high demand for applications.We report a facile strategy of ultrafast laser direct writing(ULDW)to produce large-scale embedded st...Printing stable color with a lithography-free and environment-friendly technique is in high demand for applications.We report a facile strategy of ultrafast laser direct writing(ULDW)to produce large-scale embedded structural colors inside transparent solids.The diffraction effect of gratings enables effective generation of structural colors across the entire visible spectrum.The structural colors inside the fused silica glass have been demonstrated to exhibit excellent thermal stability under high temperature up to 1200℃, which promises that the written information can be stable for long time even with unlimited lifetime at room temperature.The structural colors in the applications of coloring,anti-counterfeiting,and information storage are also demonstrated.Our studies indicate that the presented ULDW allows for fabricating large-scale and high thermal-stability structural colors with prospects of three-dimensional patterning,which will find various applications,especially under harsh conditions such as high temperature.展开更多
It is of great scientific significance to construct a 3D dynamic structural color with a special color effect based on the microlens array.However,the problems of imperfect mechanisms and poor color quality need to be...It is of great scientific significance to construct a 3D dynamic structural color with a special color effect based on the microlens array.However,the problems of imperfect mechanisms and poor color quality need to be solved.A method of 3D structural color turning on periodic metasurfaces fabricated by the microlens array and self-assembly technology was proposed in this study.In the experiment,Polydimethylsiloxane(PDMS)flexible film was used as a substrate,and SiO2 microspheres were scraped into grooves of the PDMS film to form 3D photonic crystal structures.By adjusting the number of blade-coated times and microsphere concentrations,high-saturation structural color micropatterns were obtained.These films were then matched with microlens arrays to produce dynamic graphics with iridescent effects.The results showed that by blade-coated two times and SiO2 microsphere concentrations of 50%are the best conditions.This method demonstrates the potential for being widely applied in the anticounterfeiting printing and ultra-high-resolution display.展开更多
Structural colors based on metasurfaces have very promising applications in areas such as optical image encryption and color printing.Herein,we propose a deep learning-enabled reverse design of polarization-selective ...Structural colors based on metasurfaces have very promising applications in areas such as optical image encryption and color printing.Herein,we propose a deep learning-enabled reverse design of polarization-selective structural color based on coding metasurface.In this study,the long short-term memory(LSTM)neural network is presented to enable the forward and inverse mapping between coding metasurface structure and corresponding color.The results show that the method can achieve 98%accuracy for the forward prediction of color and 93%accuracy for the inverse design of the structure.Moreover,a cascaded architecture is adopted to train the inverse neural network model,which can solve the nonuniqueness problem of the polarization-selective color reverse design.This study provides a new path for the application and development of structural colors.展开更多
Localized manipulation of light interference and phase through surface microstructures provides new viable technologies for applications such as anti-counterfeiting,camouflage,high-density optical storage and display....Localized manipulation of light interference and phase through surface microstructures provides new viable technologies for applications such as anti-counterfeiting,camouflage,high-density optical storage and display.However,the single-color rendering mechanism and the material’s intrinsic properties,such as hydrophilicity,low hardness and low melting point,limit the range of applications.In this paper,we propose a structural color based on ultrathin ZrO_(2)thin films,which presents a visible full-spectrum color display.The structural color coating has ultrahigh flame retardancy,super UV resistance,super surface hardness and resistance to acid and alkali corrosion.The use of two different color development mechanisms realizes the hiding of the quick response(QR)code in visible light.The modified film exhibits superhydrophobic properties,unique anti-icing and self-cleaning properties,and shows the material’s potential for camouflage,anti-counterfeiting,military,marine and aerospace applications.展开更多
Color as an indispensable element in our life brings vitality to us and enriches our lifestyles through decorations,indicators,and information carriers.Structural color offers an intriguing strategy to achieve novel f...Color as an indispensable element in our life brings vitality to us and enriches our lifestyles through decorations,indicators,and information carriers.Structural color offers an intriguing strategy to achieve novel functions and endows color with additional levels of significance in anti-counterfeiting,display,sensor,and printing.Furthermore,structural colors possess excellent properties,such as resistance to extreme external conditions,high brightness,saturation,and purity.Devices and platforms based on structural color have significantly changed our life and are becoming increasingly important.Here,we reviewed four typical applications of structural color and analyzed their advantages and shortcomings.First,a series of mechanisms and fabrication methods are briefly summarized and compared.Subsequently,recent progress of structural color and its applications were discussed in detail.For each application field,we classified them into several types in terms of their functions and properties.Finally,we analyzed recent emerging technologies and their potential for integration into structural color devices,as well as the corresponding challenges.展开更多
Structural colors originated from Mie scattering of dielectric spheres can be regulated by the coupling effect between them and substrates.Here a rapid visual identification method of silver ornaments was proposed by ...Structural colors originated from Mie scattering of dielectric spheres can be regulated by the coupling effect between them and substrates.Here a rapid visual identification method of silver ornaments was proposed by the coupling effect of Zn O spheres with them.Both simulation and experimental results proved that,by coupling with different metal substrates,the Mie resonance scattering peaks of ZnO spheres with dimeter of 700 nm showed different degrees of redshift,which lead to different structural color appeared when ZnO spheres deposited on different metal surfaces with a similar appearance.A red structural color was displayed on the surface of the real silver ornament and a yellow-green structural color was shown on the surface of the cupronickel ornament.This method is quite simple and low-cost because it only needs to spray the dispersion of ZnO spheres on the ornament surface.Due to the mild chemical properties of the ZnO,covering and erasing ZnO spheres on the surface of silver would not corrode the silver ornament.Finally,an atomizer method was used for portable and daily testing.This work opens new perspectives on the visual identification of silver.展开更多
Large-area and free-standing photonic crystal(PC)polymer films exhibit highly saturated iridescence and robust structural colors,making them promising for applications in the field of display,anti-counterfeiting,and c...Large-area and free-standing photonic crystal(PC)polymer films exhibit highly saturated iridescence and robust structural colors,making them promising for applications in the field of display,anti-counterfeiting,and camouflage.However,their practical utilization has been hindered by challenges in achieving both vivid coloration and reusability.Here,we design a sandwich-structured PC film that simultaneously addresses issues of color appearance and reusability by combining colloid evaporative self-assembly on porous substrate and knife coating of polymers.The unique“sandwich”structure,comprising a self-assembled PC intermediate layer and protective polymer encapsulation,demonstrates a great synergistic effect(“1+1>2”),including unprecedented color fastness stability(affordable for 100 times dye/wet fastness),bright iridescent color,and certain flexibility and reusability.In addition,by replacing the bottom polymer with a double-sided adhesive,a flexible PC sticker can be further obtained,broadening its range of applications to surfaces of different materials.This strategy opens a new avenue for constructing functionalized iridescent PC-polymer films.展开更多
In nature,many living organisms exhibiting unique structural coloration and soft-bodied actuation have inspired scientists to develop advanced structural colored soft actuators toward biomimetic soft robots.However,it...In nature,many living organisms exhibiting unique structural coloration and soft-bodied actuation have inspired scientists to develop advanced structural colored soft actuators toward biomimetic soft robots.However,it is challenging to simultaneously biomimic the angle-independent structural color and shape-morphing capabilities found in the plum-throated cotinga flying bird.Herein,we report biomimetic MXene-based soft actuators with angle-independent structural color that are fabricated through controlled self-assembly of colloidal SiO_(2) nanoparticles onto highly aligned MXene films followed by vacuum-assisted infiltration of polyvinylidene fluoride into the interstices.The resulting soft actuators are found to exhibit brilliant,angle-independent structural color,as well as ultrafast actuation and recovery speeds(a maximum curvature of 0.52 mm−1 can be achieved within 1.16 s,and a recovery time of~0.24 s)in response to acetone vapor.As proof-of-concept illustrations,structural colored soft actuators are applied to demonstrate a blue gripper-like bird’s claw that can capture the target,artificial green tendrils that can twine around tree branches,and an artificial multicolored butterfly that can flutter its wings upon cyclic exposure to acetone vapor.The strategy is expected to offer new insights into the development of biomimetic multifunctional soft actuators for somatosensory soft robotics and next-generation intelligent machines.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.52233001,51927805,and 52173110)the Innovation Program of Shanghai Municipal Education Commission(No.2023ZKZD07)the Shanghai Rising-Star Program(No.22QA1401200)。
文摘Cholesteric liquid crystals(CLCs)exhibit unique helical superstructures that selectively reflect circularly polarized light,enabling them to dynamically respond to environmental changes with tunable structural colors.This dynamic color-changing capability is crucial for applications that require adaptable optical properties,positioning CLCs as key materials in advanced photonic technologies.This review focuses on the mechanisms of dynamic color tuning in CLCs across various forms,including small molecules,cholesteric liquid crystal elastomers(CLCEs),and cholesteric liquid crystal networks(CLCNs),and emphasizes the distinct responsive coloration each structure provides.Key developments in photochromic mechanisms based on azobenzene,dithienylethene,and molecular motor switches,are discussed for their roles in enhancing the stability and tuning range of CLCs.We examine the color-changing behaviors of CLCEs under mechanical stimuli and CLCNs under swelling,highlighting the advantages of each form.Following this,applications of dynamic color-tuning CLCs in information encryption,adaptive camouflage,and smart sensing technologies are explored.The review concludes with an outlook on current challenges and future directions in CLC research,particularly in biomimetic systems and dynamic photonic devices,aiming to broaden their functional applications and impact.
基金supported by the National Natural Science Foundation of China(Grant No.61925307).
文摘Dynamic structuralcolors can change in response todifferent environmental stimuli.This ability remains effectiveeven when the size of the speciesresponsible for the structural coloris reduced to a few micrometers,providing a promising sensingmechanism for solving microenvironmentalsensing problems inmicro-robotics and microfluidics.However, the lack of dynamicstructural colors that can encoderapidly, easily integrate, and accuratelyreflect changes in physical quantities hinders their use in microscale sensing applications. Herein, we present a 2.5-dimensionaldynamic structural color based on nanogratings of heterogeneous materials, which were obtained by interweaving a pH-responsive hydrogelwith an IP-L photoresist. Transverse gratings printed with pH-responsive hydrogels elongated the period of longitudinal grating in the swollenstate, resulting in pH-tuned structural colors at a 45° incidence. Moreover, the patterned encoding and array printing of dynamic structuralcolors were achieved using grayscale stripe images to accurately encode the periods and heights of the nanogrid structures. Overall, dynamicstructural color networks exhibit promising potential for applications in information encryption and in situ sensing for microfluidic chips.
基金supported by The National Key Re-search and Development Program of China(No.2021YFD1600402)the Central Guidance on Local Science and Technology Devel-opment Fund of Shaanxi Province(No.2020-ZYYD-NCC-9)+8 种基金the Shaanxi Provincial Department of Education Collaborative In-novation Center Project(No.20JY052)the National Natural Science Foundation of China(Nos.51802259 and 51372200)the China Postdoctoral Science Foundation Funded Project(No.2019M663785)the Natural Science Foundation of Shaanxi(No.2019JQ-510)the Opening Project of Shanxi Key Laboratory of Ad-vanced Manufacturing Technology(No.XJZZ202001)the Scientific Research Project of Shaanxi Education Department(No.20JS108)the Promotion Program for Youth of Shaanxi University science and technology association(No.20190415)the Fund of Key laboratory of Processing and Quality Evaluation Technology of Green Plastics of China National Light Industry council(No.PQETGP2019003)the Innovation Guidance of Technology Program of Shaanxi Province(No.2020CGXNG-022).
文摘Inspired by special color-forming organisms in nature,photonic crystal materials with structural color function have been developed significantly with great potential applications for displays,sensors,anti-counterfeiting inks,etc.This review aims to summarize the functions,self-assembly modes,and ap-plications of different kinds of photonic crystal materials.The preparation methods and characteristics of monodisperse inorganic nanoparticles,polymer nanoparticles,inorganic/organic core-shell nanoparti-cles,and MOFs are discussed.Subsequently,we summarize the method of assembling colloidal parti-cles into photonic crystals,which is a template induction method,inkjet printing method,drop coating method,etc.Moreover,the potential application of structural color is presented including humidity re-sponse and magnetic field response in sensors fields,as well as the advantages and disadvantages of anti-counterfeiting,fabric coloring,displays,smart windows,and Biomedical Applications.Finally,we present the development prospects and key problems of photonic crystals.
文摘Soft actuators have garnered substantial attention in current years in view of their potential appliances in diverse domains like robotics,biomedical devices,and biomimetic systems.These actuators mimic the natural movements of living organisms,aiming to attain enhanced flexibility,adaptability,and versatility.On the other hand,angle-independent structural color has been achieved through innovative design strategies and engineering approaches.By carefully controlling the size,shape,and arrangement of nanostructures,researchers have been able to create materials exhibiting consistent colors regardless of the viewing angle.One promising class of materials that holds great potential for bioinspired soft actuators is MXenes in view of their exceptional mechanical,electrical,and optical properties.The integration of MXenes for bioinspired soft actuators with angle-independent structural color offers exciting possibilities.Overcoming material compatibility issues,improving color reproducibility,scalability,durability,power supply efficiency,and cost-effectiveness will play vital roles in advancing these technologies.This perspective appraises the development of bioinspired MXene-centered soft actuators with angleindependent structural color in soft robotics.
基金National Natural Science Foundation of China(10874105)Natural Science Foundation of Shandong Province(ZR2020KA009)。
文摘Structural colors with high saturation,large gamut,high resolution,and tunable color are expected in practical applications.This work explores the generation of tunable structural color based on transmission metasurfaces.The designed metasurfaces consist of rectangular nanoholes etched in silver film,which is deposited on the stretchable polydimethylsiloxane(PDMS)substrate.The smaller separation of adjacent nanoholes makes the resolution of metasurface reach 63,500 dpi.The color gamut of the nanostructures reaches 146.9%sRGB.We also perform a comparison with the case on the glass substrate and analyze the incident polarization condition and the coating film of polymethyl methacrylate(PMMA).The ultra-thin structure,high resolution,highperformance structural colors,and convenient transmission mode provide broad application prospects for metasurfaces in color displaying,color printing,and color holographic imaging.
基金National Key Research and Development Program of China(2024YFA1209104)National Natural Science Foundation of China(12374282,61875225)。
文摘Structural colors have always attracted much attention due to important applications in display devices,imaging security certification,optical data storage,and so on.The brightness of structure colors,as the carrier of chiaroscuro information,is the key to making images appear stronger in the spatial and three-dimensional sense.However,relatively little work has been done on the control of the color brightness,and the reported structures are complex and difficult to fabricate.Here,we demonstrate a low-aspect-ratio anisotropic metasurface consisting of a PMMA film patterned by arrays of elliptical-shaped holes clamped by two thin aluminum films.By utilizing localized surface plasmon resonances,we realize a three-dimensional(3D)HSB(hue,saturation,and brightness)structure color with independent brightness control and enhance the cross-polarization reflection,covering approximately 120%of the s RGB color gamut.It is shown that the ratio of the major and minor axes leads to the independent control of brightness of the structural colors.The nanoprinting of HSB images with smooth brightness transitions is demonstrated through elaborate design of the metasurface geometry parameters and CMOScompatible micro-nano fabrication process.Our findings will facilitate the broad range of 3D nanoprinting and modern advanced display applications.
基金supported by the National Natural Science Foundation of China(12474317 and 62105269)。
文摘We experimentally demonstrate ultrafast laser-writing wide-gamut structural colors on TiAlN thin film that is coated on TiN substrate via laser-induced surface oxidation.The experiments involve thorough control over laser parameters,including powers,scanning speeds and pulse durations,to investigate the interplay between these variables and the resulting structural colors.Surface characterization techniques,such as scanning electron microscopy,energy-dispersive x-ray spectroscopy and atomic force microscopy,are employed to analyze the properties of laser-induced oxide layers and their chromatic responses.Our findings indicate that while laser powers and scanning speeds are critical in determining the irradiated dose and the subsequent coloring effects,the pulse duration exerts a distinct influence,particularly at low laser powers as well as slow scanning speeds.Longer pulse durations are found to produce a more significant coloring change despite exhibiting lower oxygen content.This is attributed to the increased surface roughness and deeper oxidation layer achieved with prolonged pulses.We propose two oxidation mechanisms–photo-oxidation and thermal-oxidation–to elucidate the influence of pulse duration on laser coloring effects.These findings not only refine existing paradigms in laser-induced surface coloration but also stimulate further exploration of structural colors’multifaceted applications across diverse technological contexts.
基金financial supported by the National Science Fund for Distinguished Young Scholars(22225502)the National Natural Science Foundation of China(22435004,22073107,and 52321006)the Bureau of International Cooperation,Chinese Academy of Sciences(027GJHZ2022044MI).
文摘Through millennia of evolution,some organisms can change colors rapidly for camouflage,communication,attraction,and warning to adapt to the dynamic environment.By mimicking the dynamic coloration strategies of natural organisms,artificial materials with responsive structural colors have emerged as promising candidates due to their environmental friendliness,real-time responsiveness to stimuli,and wide color gamut.These materials have attracted immense interest in anti-counterfeiting,displays,sensing,and smart actuators.This paper aims to present a survey on the response mechanisms,color modulation strategies,and applications of the structural color materials that are developed from different principles,such as photonic crystals(PCs),liquid crystals(LCs),and metasurfaces.We first discussed various structural color materials and their colorization mechanisms.We then classified these materials according to their color regulation strategies,such as responsiveness to physical,chemical,and biological stimuli.Subsequently,we provided a comprehensive overview of their applications for anti-counterfeiting,display technologies,sensing devices and detection platforms,and the biomedical field.Finally,we discuss the future prospects of responsive structural color materials and the issues that need to be addressed for their improvement.This review not only summarizes modulation strategies for dynamic structural colors but also provides valuable references and insights for future research in the field of structural coloration.
基金the National Natural Science Foundation of China(21878042,21476040 and 21276040)the Fund for Innovative Research Groups of the National Natural Science Foundation of China Committee of Science(21421005)。
文摘Structural color materials,which generate colors through the interaction between light and nano-microstructures,have always been research hotspots in the fields of display,anticounterfeiting and stimuli-responsive materials.Structural colors based on scattering have received increasing attention due to their wider viewing angles than that originating from the specular reflection of photonic crystals.However,the wide scattering spectrum of an amorphous structure leads to lower purity and brightness of the appeared colors.Few researchers have focused on the scattering of ordered structures due to their strong reflection and diffraction in the visible regions.In this work,by building ordered films(OFs)using SiO2 spheres(refractive index n=1.46)with a diameter of 300–500 nm,for the first time,sharp scattering spectra with narrow full width at half-maximum(FWHM,24 nm)were generated.Importantly,under ambient light,brilliant colors covering the entire visible region can be observed,and a formula was proposed to calculate the scattering spectra of OFs.Moreover,rainbow structural color was realized under irradiation of the nonparallel light,and full-spectrum structural color patterns were fabricated using building blocks with a single particle size by a spraying method.Finally,a composite structure was constructed to explore possibilities in the field of flexible transparent displays.
基金the Air Force Office of Scientific Research(MURI:FA9550-14-1-0389)for financial supportthe Center for Nanoscale Systems(CNS),a member of the National Nanotechnology Coordinated Infrastructure(NNCI)+3 种基金supported by the National Science Foundation under NSF award no.1541959.CNS is part of Harvard Universitysupport from KAUST(Award CRG-1-2012-FRA-005)the financial support of the‘Size matters’project(TDA Capital Ltd,London,UK)the financial support by the Master Thesis Grant of the Zeno Karl Schindler Foundation(Switzerland).
文摘Structural colors have drawn wide attention for their potential as a future printing technology for various applications,ranging from biomimetic tissues to adaptive camouflage materials.However,an efficient approach to realize robust colors with a scalable fabrication technique is still lacking,hampering the realization of practical applications with this platform.Here,we develop a new approach based on large-scale network metamaterials that combine dealloyed subwavelength structures at the nanoscale with lossless,ultra-thin dielectric coatings.By using theory and experiments,we show how subwavelength dielectric coatings control a mechanism of resonant light coupling with epsilon-near-zero regions generated in the metallic network,generating the formation of saturated structural colors that cover a wide portion of the spectrum.Ellipsometry measurements support the efficient observation of these colors,even at angles of 70°.The network-like architecture of these nanomaterials allows for high mechanical resistance,which is quantified in a series of nano-scratch tests.With such remarkable properties,these metastructures represent a robust design technology for real-world,large-scale commercial applications.
基金supported by the National Key Research and Development Program of China(No.2020YFC2200400)the National Natural Science Foundation of China(No.62375231)the Fujian Province Science and Technology Planning Project of China(No.2022H6015)。
文摘Recently, the Fano resonance has played an increasingly important role in improving the color performance of structural colors. In this study, we further elucidate the asymmetric spectral shape generated by Fano resonance from a phase perspective and explore four distinct continuum state structures. By integrating the proposed cavity-like structure with a metal±dielectric±metal discrete state, multilayered thin-film structural colors with minimal background reflection, as low as 8%, were successfully achieved. The reflection peak of this structure exhibits a bandwidth of approximately50 nm and reaches up to 80%, indicating heightened saturation and color brightness. Moreover, by adjusting the thickness,we effortlessly obtained a broader color gamut compared to Adobe RGB (45.2%), covering 56.7% of the CIE color space. Even adjusting a single layer can achieve a color gamut of 47.1%. In experiments, by deliberately choosing low oxygendependent materials, excellent RGB colors with high brightness and in high consistency with simulation results were successfully achieved. Therefore, the scheme's simple process for structural color creation, along with its excellent color performance and the ability to effectively replicate simulation characteristics makes it highly valuable in fields like anticounterfeiting, decoration, display devices, and solar cell panels.
基金supported by the POSCO-POSTECH-RIST Convergence Research Center program funded by POSCOthe National Research Foundation(NRF)grants(RS-2022-NR067559,RS-2023-00302586)funded by the Ministry of Science and ICT(MSIT)of the Korean government.
文摘Wenhao Wang and colleagues summarized the latest advancements in structural color research in Opto-Electronic Science. Their review explored the fundamental principles and fabrication methods of structural colors for photonic applications, including anti-counterfeiting, displays, sensors, and printing, along with their practical limitations. Recently, structural colors have received growing interest due to their advantages, including physical and chemical robustness, ecofriendliness, tunability, and high-resolution color.
基金This work was financially supported by the National Key R&D Program of China(No.2021YFB2800500)National Natural Science Foundation of China(Nos.U20A20211,51902286,61775192,61905215,and 51772270)+1 种基金Open Funds of the State Key Laboratory of High Field Laser Physics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of SciencesFundamental Research Funds for the Central Universities.
文摘Printing stable color with a lithography-free and environment-friendly technique is in high demand for applications.We report a facile strategy of ultrafast laser direct writing(ULDW)to produce large-scale embedded structural colors inside transparent solids.The diffraction effect of gratings enables effective generation of structural colors across the entire visible spectrum.The structural colors inside the fused silica glass have been demonstrated to exhibit excellent thermal stability under high temperature up to 1200℃, which promises that the written information can be stable for long time even with unlimited lifetime at room temperature.The structural colors in the applications of coloring,anti-counterfeiting,and information storage are also demonstrated.Our studies indicate that the presented ULDW allows for fabricating large-scale and high thermal-stability structural colors with prospects of three-dimensional patterning,which will find various applications,especially under harsh conditions such as high temperature.
文摘It is of great scientific significance to construct a 3D dynamic structural color with a special color effect based on the microlens array.However,the problems of imperfect mechanisms and poor color quality need to be solved.A method of 3D structural color turning on periodic metasurfaces fabricated by the microlens array and self-assembly technology was proposed in this study.In the experiment,Polydimethylsiloxane(PDMS)flexible film was used as a substrate,and SiO2 microspheres were scraped into grooves of the PDMS film to form 3D photonic crystal structures.By adjusting the number of blade-coated times and microsphere concentrations,high-saturation structural color micropatterns were obtained.These films were then matched with microlens arrays to produce dynamic graphics with iridescent effects.The results showed that by blade-coated two times and SiO2 microsphere concentrations of 50%are the best conditions.This method demonstrates the potential for being widely applied in the anticounterfeiting printing and ultra-high-resolution display.
基金supported by the National Natural Science Foundation of China(Grant Nos.62375137 and 62175114).
文摘Structural colors based on metasurfaces have very promising applications in areas such as optical image encryption and color printing.Herein,we propose a deep learning-enabled reverse design of polarization-selective structural color based on coding metasurface.In this study,the long short-term memory(LSTM)neural network is presented to enable the forward and inverse mapping between coding metasurface structure and corresponding color.The results show that the method can achieve 98%accuracy for the forward prediction of color and 93%accuracy for the inverse design of the structure.Moreover,a cascaded architecture is adopted to train the inverse neural network model,which can solve the nonuniqueness problem of the polarization-selective color reverse design.This study provides a new path for the application and development of structural colors.
基金supported by the National Key Research and Development Program of China(No.2021YFA1401100)the National Natural Science Foundation of China(Nos.61825403 and 61921005).
文摘Localized manipulation of light interference and phase through surface microstructures provides new viable technologies for applications such as anti-counterfeiting,camouflage,high-density optical storage and display.However,the single-color rendering mechanism and the material’s intrinsic properties,such as hydrophilicity,low hardness and low melting point,limit the range of applications.In this paper,we propose a structural color based on ultrathin ZrO_(2)thin films,which presents a visible full-spectrum color display.The structural color coating has ultrahigh flame retardancy,super UV resistance,super surface hardness and resistance to acid and alkali corrosion.The use of two different color development mechanisms realizes the hiding of the quick response(QR)code in visible light.The modified film exhibits superhydrophobic properties,unique anti-icing and self-cleaning properties,and shows the material’s potential for camouflage,anti-counterfeiting,military,marine and aerospace applications.
基金financially supported by the Natural Science Foundation of Shaanxi Province(Grant No.2024JC-YBMS-291)Special Support Program for High-level Talents of Shaanxi Province(No.2020-44)。
文摘Color as an indispensable element in our life brings vitality to us and enriches our lifestyles through decorations,indicators,and information carriers.Structural color offers an intriguing strategy to achieve novel functions and endows color with additional levels of significance in anti-counterfeiting,display,sensor,and printing.Furthermore,structural colors possess excellent properties,such as resistance to extreme external conditions,high brightness,saturation,and purity.Devices and platforms based on structural color have significantly changed our life and are becoming increasingly important.Here,we reviewed four typical applications of structural color and analyzed their advantages and shortcomings.First,a series of mechanisms and fabrication methods are briefly summarized and compared.Subsequently,recent progress of structural color and its applications were discussed in detail.For each application field,we classified them into several types in terms of their functions and properties.Finally,we analyzed recent emerging technologies and their potential for integration into structural color devices,as well as the corresponding challenges.
基金supported by the National Natural Science Foundation of China(Nos.22178047 and 21878042)the Dalian Science and Technology Innovation Fund(No.2020JJ26GX046)the Fundamental Research Funds for the Central Universities(Nos.DUT22LAB610 and DUT2022TB10)。
文摘Structural colors originated from Mie scattering of dielectric spheres can be regulated by the coupling effect between them and substrates.Here a rapid visual identification method of silver ornaments was proposed by the coupling effect of Zn O spheres with them.Both simulation and experimental results proved that,by coupling with different metal substrates,the Mie resonance scattering peaks of ZnO spheres with dimeter of 700 nm showed different degrees of redshift,which lead to different structural color appeared when ZnO spheres deposited on different metal surfaces with a similar appearance.A red structural color was displayed on the surface of the real silver ornament and a yellow-green structural color was shown on the surface of the cupronickel ornament.This method is quite simple and low-cost because it only needs to spray the dispersion of ZnO spheres on the ornament surface.Due to the mild chemical properties of the ZnO,covering and erasing ZnO spheres on the surface of silver would not corrode the silver ornament.Finally,an atomizer method was used for portable and daily testing.This work opens new perspectives on the visual identification of silver.
基金financially supported by the National Natural Science Foundation of China(Nos.22178047 and 21878042)the Fundamental Research Funds for the Central Universities(No.DUT22LAB610)Liaoning province science and technology plan projects(No.2022JH2/101300233).
文摘Large-area and free-standing photonic crystal(PC)polymer films exhibit highly saturated iridescence and robust structural colors,making them promising for applications in the field of display,anti-counterfeiting,and camouflage.However,their practical utilization has been hindered by challenges in achieving both vivid coloration and reusability.Here,we design a sandwich-structured PC film that simultaneously addresses issues of color appearance and reusability by combining colloid evaporative self-assembly on porous substrate and knife coating of polymers.The unique“sandwich”structure,comprising a self-assembled PC intermediate layer and protective polymer encapsulation,demonstrates a great synergistic effect(“1+1>2”),including unprecedented color fastness stability(affordable for 100 times dye/wet fastness),bright iridescent color,and certain flexibility and reusability.In addition,by replacing the bottom polymer with a double-sided adhesive,a flexible PC sticker can be further obtained,broadening its range of applications to surfaces of different materials.This strategy opens a new avenue for constructing functionalized iridescent PC-polymer films.
基金supported by the National Natural Science Foundation of China(Nos.51973155,52173181,and 52173262)Jiangsu Innovation Team Program,Natural Science Foundation of Tianjin(20JCYBJC00810).
文摘In nature,many living organisms exhibiting unique structural coloration and soft-bodied actuation have inspired scientists to develop advanced structural colored soft actuators toward biomimetic soft robots.However,it is challenging to simultaneously biomimic the angle-independent structural color and shape-morphing capabilities found in the plum-throated cotinga flying bird.Herein,we report biomimetic MXene-based soft actuators with angle-independent structural color that are fabricated through controlled self-assembly of colloidal SiO_(2) nanoparticles onto highly aligned MXene films followed by vacuum-assisted infiltration of polyvinylidene fluoride into the interstices.The resulting soft actuators are found to exhibit brilliant,angle-independent structural color,as well as ultrafast actuation and recovery speeds(a maximum curvature of 0.52 mm−1 can be achieved within 1.16 s,and a recovery time of~0.24 s)in response to acetone vapor.As proof-of-concept illustrations,structural colored soft actuators are applied to demonstrate a blue gripper-like bird’s claw that can capture the target,artificial green tendrils that can twine around tree branches,and an artificial multicolored butterfly that can flutter its wings upon cyclic exposure to acetone vapor.The strategy is expected to offer new insights into the development of biomimetic multifunctional soft actuators for somatosensory soft robotics and next-generation intelligent machines.
