Highly Efficient Fabricating Amorphous Photonic Crystals Using Less Polar Solvents and the Wettability‐Based Information Storage and Recognition

Abstract

printing, [23][24][25][26][27][28][29] anticounterfeiting, [30][31][32][33][34][35][36][37][38] photo catalysis, [39][40][41] optical device, [42][43][44][45][46] and solar energy. [47][48][49][50] According to the order degree of the structures, the PCs can be divided into highly ordered photonic crystals (OPCs) and amorphous photonic crystals (APCs). These two kinds of PCs show considerable difference in the optical properties. The OPCs with long-range ordered structures show iridescent structural colors, while the APCs with only short-range order exhibit non-iridescent structural colors. For some applications, such as color displays or sensors, [51][52][53][54] angle independent colors are necessary and required. In this regard, APCs with angle independent structural colors show inherent advantages than the OPCs owing to the amorphous packing of the particles. However, the fabrication of APCs remains a big challenge. In particular, the charged colloidal particles tend to crystalize and form long-range order upon the assembly process, which make it rather difficult to prepare APCs.Recently, there have been attempts to fabricate APCs through the dynamic or thermodynamic controlling the assembly process. Spray [55,56] and infiltration [57] are efficient in preparing APCs based on the rapid remove of solvents from the colloidal solution, respectively. In both approaches, the fast remove of solvents will break the longrange packing tendency of particles, resulting in the shortrange order. However, the usage of the environmentally harmful solvent or porous substrates in these two methods will limit their practical utility. Layer by layer strategy [58] is promising in preparing APCs based on consecutively polyelectrolyte coating process but subjected to the tedious and time-consuming processes. Although the bi-disperse suspension [59,60] is successful for fabrication of APCs, it is essential to control the difference in particle size to guarantee the bright colors of APCs. Alternatively, APCs can be fabricated by the self-assembly of soft particles. [61,62] With this approach, subtle fabrications must be well controlled to ensure the success of controlling the thickness of the shell and the assembly of soft particles. Except for the fabrication, the APCs usually exhibit pale structural colors due to the strong multiple scattering light. To deal with this problem, carbon black or other black particles are introduced into the APCs to absorb the Facile and efficient fabrication of amorphous photonic crystals (APCs) with uniform and angle independent structural colors is highly desired due to their unique applications in non-iridescent colors-based displays, pigments, and sensors. Here, a solvent-assisted colloidal assembly approach is reported to fabricate APCs with uniform and angle-independent structural colors by the self-assembly of polydopamine-embedded silica particles in pentanol. The surface charge of the particle mediated by the polarity of solvent is demonstrated to be the key to control the particle arrangeme...

Self-assembly of colloidal particles into amorphous photonic crystals

“…In addition, we reported a novel method to prepare APCs with noniridescent structural colors by assembling colloidal particles in less-polar dispersant. 179 Based on the sensitivity of the APCs to the refractive index contrast, their structural color disappears once the APCs is wetted. Accordingly, we developed an information storage system for water recognition.…”

“…In our work on assembling the APCs by less polar solvents, a novel system for information storage and identification was developed based on the wetting character of APCs. Their structural colors disappear by wetting due to the reduction of the internal refractive index contrast 179. A 6-circular-grids system was constructed with APCs whose displaying region were hydrophobic after treated with fluoroalkylsilane and the background remained hydrophilic.…”

Dual‐Modal Invisible Photonic Crystal Prints from Photo/Water Responsive Photonic Crystals

“…Photonic crystals (PCs) exhibit potential applications in the field of color display, [1][2][3][4][5][6][7] pigment, [8][9][10][11] printing/pattern, [12][13][14][15][16][17][18] sensing, [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] chemical separation, [36,37] anti-counterfeiting, [38][39][40][41][42][43][44][45][46][47][48][49][50][51][...…”

“…Photonic crystals (PCs) exhibit potential applications in the field of color display, [ 1–7 ] pigment, [ 8–11 ] printing/pattern, [ 12–18 ] sensing, [ 19–35 ] chemical separation, [ 36,37 ] anti‐counterfeiting, [ 38–53 ] and photocatalysis, [ 54–57 ] benefiting from the unique periodic structures. The color of the PC comes from the diffraction, interference, and scattering of light by its ordered structures, which can be altered by the lattice constant, refractive index, and orientations of the crystal.…”

Refractive‐Index‐Matching‐Based Encryption of Photonic Crystal Prints with Multistage and Reconfigurable Information

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make PCs applicable in the fields of displays, [6][7][8][9][10][11][12] printings, [13][14][15][16][17][18][19] pigments, [20][21][22][23] biology, [24,25] sensing, [26][27][28][29][30][31][32][33][34][35][36][37] photocatalysis, [38] and anticounterfeiting. [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56] As a member of PCs, the encrypted photon...

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