Tunable, Cost‐Effective, and Scalable Structural Colors for Sensing and Consumer Products

Abstract

color displays, [4][5][6][7] optical anti-counterfeiting, [8][9][10][11] and camouflaging. [12] Various systems have been employed to realize structural colors, such as plasmonic resonators, [13][14][15] all-dielectric systems, [16][17][18][19][20] and diffraction gratings. [21][22][23][24] These systems take advantage of various physical resonances and mechanisms such as surface plasmons, gap plasmons, [25][26][27] Mie resonances, [28][29][30] and thin-film interference. [19,31,32] In particular, structural colors based on thin-film interference such as Fabry-Perot (FP) cavity are promising as they can be easily scaled up, patterned using different processes, and produce vibrant colors. [19,33] Structural color elements can be designed such that they visually respond to different external stimuli through the use of suitable materials in an optically resonant system. Various optical systems such as FP, [34][35][36] Bragg reflector, [37] plasmonic, [38][39][40] and photonic crystal [41] structure types have been employed to realize such stimuli-responsive systems. Various materials such as hydrogels, [34,35,38,39] 2D materials, [37] and phase changing materials (i.e., VO 2 , Sb 2 S 3 ) [36,42] have been exploited in structural color responsive systems. Depending on the material that is incorporated into the optical system, the system can respond to one or multiple stimuli such as temperature and humidity. [38,39] While multiple demonstrations have been made, the issue of cost and simplicity of device design has yet to be fully addressed.Of the various external stimuli, a chemical response is of great importance. In chemical sensing, changes in the environment are detected by transforming the change into an analytically useful output such as color. [43][44][45] To this end, materials that respond to certain chemicals are integrated into an optical resonator. For instance, the poly(2-hydroxyethyl methacrylate-coacrylic acid) hydrogel was covalently bonded to a silicon (Si) substrate to realize a sensor through the thin-film interference effect to detect volatile organic compounds. [34] In another work, copper ions and glycoprotein were detected using an FP cavity made by sandwiching poly(acrylamide-co-acrylic acid-co-N-allyl acrylamide) hydrogel between Si substrate and a gold (Au) film through spectrometric measurements. [35] Previous reports do not provide enough color variation, lack saturated colors that are easy to distinguish visually, need spectrometric measurements, or use costly materials and processes.The cost-effective colorimetric detection of chemicals can be a potential substitute for expensive spectrometers. Here, a structural color sensor is presented that can distinguish seven different organic solvents through a timed sharp color change. The color sensor is based on interference effects in a metalinsulator-metal Fabry-Perot (FP) cavity with polydimethylsiloxane (PDMS) serving as the dielectric layer. By tuning the cross-linker to monomer ratio of PDMS and employing a porous nickel (Ni) top layer, t...

All-dielectric metasurface for high-performance structural color

“…With the refractive index matching layer, the simulated color gamut is around 186% of the sRGB, 138.7% of the Adobe RGB, and even approaches 99.5% of the Rec.2020. Similar to the conventional all-dielectric metasurfaces 20,30,41,42 , the structural color from Si metasurface with a refractive index matching layer (n = 1.48) are also independent to the incident angle (see Supplementary Note 19) and only slightly increase the material absorption (see Supplementary Note 20). Therefore, adding a refractive index matching layer to high refractive index all-dielectric metasurface is an effective approach to improve the structural color to the limit.…”

Metal-enhancement study of dual functional photosensitizers with aggregation-induced emission and singlet oxygen generation

“…Plasmonic nanoparticles (NPs) such as gold and silver NPs, have unprecedented ability to localize and enhance their surrounding electric eld and conne it into subwavelength volumes due to the excitation of their surface plasmon resonance (SPR) by the incident electromagnetic eld, leading to several applications from structural color printing, 8,9 energy storage, 10 and catalysis [11][12][13][14] to metal NPs-based biosensors [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] development. More recently, these localised SPR effects have been exploited to enhance the optoelectronic properties of functional materials, such as uorophores and photosensitizers, leading to a new eld of studying metal-enhanced uorescence (MEF) [30][31][32][33][34][35][36][37][38][39][40][41] and singlet oxygen generation (ME-SOG).…”

Plasmonics Induced Multifunction Optical Device via Hoof-Shaped Subwavelength Structure

“…filter device that realizes multiple channels working simultaneously by changing the number of concentric apertures [11]; A color sensor was realized using interference effects in the metal-insulatormetal Fabry-Perot (FP) cavity of polydimethylsiloxane (PDMS) as the dielectric layer [12]; The function of displaying different colors in the visible light range is realized by changing the material characteristics and the geometric parameters of the structure, in order to achieve the application of the structure color [13][14][15][16][17][18][19]. However, the devices proposed by researchers have the defects of single function, complex structure and expensive materials; they cannot achieve better performance when the devices are integrated.…”

“…In recent years, the enhanced optical transmission (EOT) effect brought by metal-based surface plasmons has been applied in different wavelengths, including visible light, near-infrared and infrared ranges. Correspondingly, a large number of micro/nano structures have been proposed, such as: circle holes [4], stripe grating hole [5], single/double aperture hole [6], composite structure [7], cross-shaped hole [8], triangular hole [9]; Also, a large number of devices and applications have been constructed, for example: A absorber device that realizes broadband multifunctional properties by introducing vanadium dioxide into a metamaterial [10]; A filter device that realizes multiple channels working simultaneously by changing the number of concentric apertures [11]; A color sensor was realized using interference effects in the metal-insulator-metal Fabry-Perot (FP) cavity of polydimethylsiloxane (PDMS) as the dielectric layer [12]; The function of displaying different colors in the visible light range is realized by changing the material characteristics and the geometric parameters 2 of 9 of the structure, in order to achieve the application of the structure color [13][14][15][16][17][18][19]. However, the devices proposed by researchers have the defects of single function, complex structure and expensive materials; they cannot achieve better performance when the devices are integrated.…”