阅读说明：本技术 一种双层光子晶体光开关薄膜器件及其制备方法 (Double-layer photonic crystal optical switch thin film device and preparation method thereof ) 是由 张淑芬 齐勇 牛文斌 武素丽 马威 唐炳涛 于 2019-11-29 设计创作，主要内容包括：本发明公开了一种同时具备2D和3D光子晶体光学特性的双层光子晶体光开关薄膜器件及其制备方法。周期性旋转该双层光子晶体光开关薄膜器件时,在固定的旋转角度可观测到不同的颜色,即其具有旋转变色属性,进而可实现光路的开和关。因此,该发明的双层光子晶体光开关薄膜新器件将在光开关、光波导、光棱镜、警示牌、防伪和信息编码等领域具有广泛的应用前景。(The invention discloses a double-layer photonic crystal optical switch thin-film device with both 2D and 3D photonic crystal optical characteristics and a preparation method thereof. When the double-layer photonic crystal optical switch thin-film device is periodically rotated, different colors can be observed at a fixed rotation angle, namely, the device has a rotary color change property, and further, the on-off of a light path can be realized. Therefore, the novel double-layer photonic crystal optical switch film device has wide application prospect in the fields of optical switches, optical waveguides, optical prisms, warning signs, anti-counterfeiting, information coding and the like.)

1. A double-layer photonic crystal optical switch film device is characterized in that an opal photonic crystal template assembled by two nano microspheres with different thicknesses is vertically staggered and combined into a sandwich structure, and a flexible polymer film material is filled in the opal photonic crystal template, wherein the flexible polymer film material is formed by copolymerizing precursor liquid formed by acrylic acid and esters thereof, mercapto-acrylate and a photoinitiator under the action of ultraviolet light; and the double-layer photonic crystal optical switch film is rotated along the plane direction of the double-layer photonic crystal optical switch film to realize the on and off of two periodical controllable light paths of 30 degrees and 60 degrees.

2. The double-layer photonic crystal optical switch thin film device according to claim 1, wherein the boundary between the thicknesses of the two opal photonic crystal templates with different thicknesses is 1-6 μm.

3. The bilayer photonic crystal optical switch film of claim 1, wherein the nanospheres are one of silica, titania, silica or titania coated polystyrene, silica or titania coated polymethylmethacrylate, silica or titania coated poly (styrene-methyl methacrylate-acrylic acid) polymer colloidal microspheres, silica coated titania, titania coated silica, cadmium sulfide and zinc oxide; and (4) carrying out lifting assembly on the nano microspheres to obtain the opal photonic crystal template.

4. The method for preparing a novel double-layer photonic crystal optical switch thin film device as claimed in claim 1, wherein the particle size of the nano-microsphere is 250-550 nm.

5. The preparation method of the novel double-layer photonic crystal optical switch thin film device according to claim 1, wherein the acrylic acid and the esters thereof are triacrylates, diacrylates and acrylic acids, and the volume ratio of the triacrylates, the diacrylates and the acrylic acids is 0.1-6: 0.1-6.

6. The method for preparing a novel double-layer photonic crystal optical switch thin film device according to claim 1, wherein the mercaptoacrylic ester is selected from one of tetra (3-mercaptopropionic acid) ester, tri (3-mercaptopropionic acid) ester and di (3-mercaptopropionic acid) ester; the volume ratio of the mercapto acrylate to the triacrylate is 0.1-1: 1.

7. The method for preparing a two-layer photonic crystal optical switch thin film device according to claim 1, wherein the photoinitiator is selected from one or two of 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexyl phenyl propanone, 2-methyl-1- (4-methylthiophenyl) -2-morpholine-1-propanone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone, phenyl bis (2,4, 6-trimethylbenzoyl) phosphine oxide, benzoin dimethyl ether and benzoin ethyl ether, and the volume ratio of the photoinitiator to the triacrylate is 0.01-0.05: 1.

8. A method of fabricating a bilayer photonic crystal optical switching thin film device as claimed in any one of claims 1 to 7, comprising the steps of:

(1) obtaining a nano microsphere opal photonic crystal template through lifting self-assembly at room temperature;

(2) taking two nano-microsphere opal photonic crystal templates with different thicknesses, and combining the templates in a 90-degree staggered manner, and separating the templates into a sandwich structure by using a polyimide adhesive tape;

(3) mixing the triacrylate, the diacrylate, the acrylic acid, the mercapto acrylate and the photoinitiator, ultrasonically dispersing uniformly, then pouring into the template with the sandwich structure obtained in the step (2), and carrying out ultraviolet curing;

(3) and stripping the upper and lower glass substrates to obtain the double-layer photonic crystal containing the nano microspheres.

9. The method for preparing a bilayer photonic crystal optical switch thin film device according to claim 8, wherein the nanospheres in the bilayer photonic crystal containing nanospheres obtained in step (3) are retained or removed.

10. The method for preparing a double-layer photonic crystal optical switch thin film device according to claim 8, wherein in the step (1), the nano-microsphere opal photonic crystal template is further mechanically engraved to obtain a patterned template.

Technical Field

The invention relates to a double-layer photonic crystal optical switch thin film device, in particular to preparation of a double-layer 3D photonic crystal thin film with two periodic reproducibility 2D photonic band gaps of 30 degrees and 60 degrees.

Background

The necessary light manipulation is particularly important for the development of intelligent optical devices. The Color conversion of most Photonic crystals depends on blue (or red) shifts of the Photonic band gap (J.B.Kim, S. -H.Kim, et al.design Structural-Color patterns composite of Color Arrays [ J ]. ACS Appl.Mat.Interfaces, 2019,11(16): 14485-. In the specular reflection mode, these band gaps change as the polymer micropores expand, contract, or form, often requiring a stimulus response to external environmental conditions (e.g., light, temperature, solvent, vapor, and pH). These devices require that the polymer used have a single characteristic or special function, such as response to humidity, temperature, vapor, pressure, light or solvent, and not be overly sensitive. Although such devices can satisfy the optical path manipulation under the stimulation of environmental conditions, they are not suitable for the optical manipulation without the above-mentioned environmental condition change (under the stimulation of non-environmental conditions), and also cannot realize the optical manipulation in the non-specular reflection mode.

In addition, the light path can be controlled by controlling the assembling mode of the nano particles and regulating the spatial arrangement of the nano particles to change the lattice spacing. Such as magnetic Assembly (Z.Li, M.Wang, et al.magnetic Assembly of Nanocubes for organization-Dependent Photonic Responses [ J ] Nano Lett.2019,19(9): 6673-. However, the special assembly forms limit the band gap of the photonic crystal and the process is complicated, which makes the reflected light of the device too single. Some physical transformation methods are also used for Photonic band gap Modulation, including Polymer scaffolds (M.Wang, C.Zou, et al.bias-polarization dependent Modulation of Photonic band in a Nanoengineered 3D blue phase Polymer Scaffold for Tunable Laser Application [ J ]. adv.optical matrix.2018, 6(16):1800409), glass transition (S.Yu, X.Cao, et al.Lange-Area and Waterwrite Photonic Crystal fibers underlying by the Thermal Application [ J ]. Inter12-Liquid interfacial analysis [ J ]. application.2019, 11(25): 787) and Photonic band transformed [ C.1415. Photonic band ] microspheres [ J.14147.19. for polymeric microspheres [ J.: 19. 12, 19. 12. for polymeric nanoparticles). These physical methods are usually based on 2D photonic crystals or 3D photonic crystals, the obtained photonic band gap is continuous, only the color of light can be changed, and the light path does not have the characteristic of periodic on and off. Meanwhile, the preparation of these nanoparticles needs to consider the surface charge, the hardness (glass transition temperature) and the deformation stimulating capability of the particles. For 2D photonic crystals, the assembly difficulty of the single-layer microspheres is far greater than that of 3D photonic crystals; and the 3D photonic crystal only has a mirror reflection mode and can realize the regulation and control of a light path. In a word, the traditional way of inducing photonic band gap changes often requires stimulation of external environmental conditions, the preparation flow of the nanoparticles is complex, and the optical path is single and continuous. The practical application of the conventional photonic crystal device is greatly limited.

In recent years, the top layer of a bi-layer photonic crystal has been made transparent by refractive index matching, enabling reversible conversion of polychromatic light (two bandgaps) to monochromatic light (one bandgap) (y.qi, l.chu, et al.new Encryption Strategy with photonic Crystals with a Bilayer inductor Guided from transmissive Response [ J ]. adv.function.mater.2019, 29: 1903743). The study of Bilayer Photonic crystals is of interest (Y.Qi, W.Niu, et al.encoding and Decoding of Inverse Complex information in a Dual-Response Bilayer Photonic Crystal with a solar cell Cooling utility [ J ]. adv.Funct.Mater.2019,29: 1906799; Y.Meng, J.Qiu, et al.biometric structural Color Films with a Bilayer inductor heterogeneous structure for the adaptive outdoor evaluation Applications [ J ]. ACS Appl.Mater.interfaces 2018, 459, 38465). The double-layer photonic crystal can obtain various band gaps only by changing angles or environmental stimulation without using complex nano particles. Compared with the traditional photonic crystal, the double-layer photonic crystal has more regulation sites and more complex color conversion characteristics. Nevertheless, the two-layer photonic crystal reported at present still depends on the mirror reflection mode of the photonic crystal, and the reflected light only changes in color, and cannot be broken or deflected. Therefore, developing a simpler bandgap tuning method remains a significant challenge.

Disclosure of Invention

The invention provides a double-layer photonic crystal optical switch thin-film device with 2D and 3D photonic crystal optical characteristics and a preparation method thereof. When the double-layer photonic crystal optical switch thin-film device is periodically rotated, different colors can be observed at a fixed rotation angle, namely, the device has a rotary color change property, and further, the on-off of a light path can be realized.

A double-layer photonic crystal optical switch film device is composed of an opal photonic crystal template assembled by two nano microspheres with different thicknesses, a sandwich structure and a flexible polymer film material filled in the sandwich structure, wherein the flexible polymer film material is formed by copolymerizing precursor liquid formed by acrylic acid and esters thereof, mercapto acrylate and a photoinitiator under the action of ultraviolet light; and the double-layer photonic crystal optical switch film is rotated along the plane direction of the double-layer photonic crystal optical switch film to realize the on and off of two periodical controllable light paths of 30 degrees and 60 degrees.

In the above technical solution, preferably, the nano-microsphere opal photonic crystal template has two thicknesses, one of which is smaller than 2 μm and the other of which is larger than 2 μm. However, the boundary of the thickness is not limited to 2 μm, and the boundary fluctuates depending on the particle size of the nanoparticles to be used, and the fluctuation range of the boundary is generally 1 to 6 μm.

In the above technical solution, preferably, the particle size of the nanoparticle is 250-550nm, and is further optimized to be 350-450 nm.

In the above technical solution, preferably, the nano-microsphere is one of silica, titania, silica or titania-coated polystyrene, silica or titania-coated polymethyl methacrylate, silica or titania-coated poly (styrene-methyl methacrylate-acrylic acid) polymer colloidal microsphere, silica-coated titania, titania-coated silica, cadmium sulfide, zinc oxide, and the like.

In the above technical solution, preferably, the opal photonic crystal template is obtained by pulling and assembling the nano-microspheres.

In the above technical scheme, preferably, the acrylic acid and its esters are composed of triacrylates, diacrylates and acrylic acids, and the volume ratio of the triacrylates, the diacrylates and the acrylic acids is 0.1-6: 0.1-6.

In the above technical solution, preferably, the triacrylate is selected from one of ethoxylated trimethylolpropane triacrylate, trimethylolpropane triacrylate and pentaerythritol triacrylate.

In the above technical solution, preferably, the diacrylate is one or two of polyethylene glycol (200) diacrylate, polyethylene glycol (400) diacrylate, polyethylene glycol (600) diacrylate and polyethylene glycol (1000) diacrylate.

In the above technical solution, preferably, the mercaptoacrylic ester is used as a modifier, and is selected from one of tetra (3-mercaptopropionic acid) esters, tri (3-mercaptopropionic acid) esters, and di (3-mercaptopropionic acid) esters, and the volume ratio of the mercaptoacrylic ester modifier to the triacrylate is 0.1-1: 1.

In the above technical solution, preferably, the mercaptoacrylic ester is one selected from pentaerythritol tetrakis (3-mercaptopropionate), trimethylolpropane tris (3-mercaptopropionate), glycerol tris (3-mercaptopropionate), and ethylene glycol bis (3-mercaptopropionate).

In the above technical solution, preferably, the photoinitiator is selected from one or two of 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173), 1-hydroxycyclohexyl phenyl acetone (184), 2-methyl-1- (4-methylthiophenyl) -2-morpholine-1-propanone (907), 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone (369), phenyl bis (2,4, 6-trimethylbenzoyl) phosphine oxide (819), benzoin dimethyl ether and benzoin ethyl ether, and the volume ratio of the photoinitiator to the triacrylate is 0.01 to 0.05: 1.

The invention also provides a preparation method of the novel double-layer photonic crystal optical switch film device, which comprises the steps of firstly obtaining a microspherical opal template with the particle size of 250-550nm by pulling and self-assembling, then combining the templates with two different thicknesses in a 90-degree staggered manner, filling precursor liquids such as acrylic acid and esters thereof, mercaptoacrylates and photoinitiators and the like, wherein the opal photonic crystal template in a sandwich structure is vertically combined in a staggered manner; and finally, obtaining the double-layer 3D photonic crystal through ultraviolet light curing, which specifically comprises the following process steps:

(1) obtaining the microspherical opal photonic crystal template with the particle size of 250-550nm by pulling self-assembly at room temperature. The thickness of the die plate becomes thicker as the number of pull cycles increases.

(2) Two nanometer microsphere opal photonic crystal templates with different thicknesses are combined in a 90-degree staggered mode and separated into a sandwich structure by a polyimide adhesive tape.

(3) Mixing the triacrylate, the diacrylate, the acrylic acid, the mercapto acrylate and the photoinitiator, ultrasonically dispersing uniformly, pouring into the sandwich structure template obtained in the step (2), and carrying out ultraviolet curing.

(4) And stripping the upper and lower glass substrates to obtain the double-layer photonic crystal containing the nano microspheres.

In the above technical solution, preferably, the nanoparticles in the nanoparticle-containing double-layered photonic crystal obtained in step (3) may be retained or removed.

In the above technical solution, preferably, the nano-microspheres in the double-layer photonic crystal containing the nano-microspheres are removed by soaking with hydrofluoric acid.

In the above technical solution, preferably, in the step (1), the nano-microsphere opal photonic crystal template may further be mechanically engraved to obtain a patterned template.

In the above technical solution, preferably, in the step (3), the conditions of the ultraviolet curing are as follows: the power is 500-1000W, and the curing time is 10-120 s; the ultraviolet lamp used for curing is a high-pressure mercury lamp.

The whole process of the invention is operated at room temperature, the condition is mild, the substrate is not limited, and the invention has wide applicability.

The invention provides the application of the novel double-layer photonic crystal optical switch film device as an optical switch, an optical waveguide, an optical prism, a warning board, an anti-counterfeiting and information coding material.

The invention has the beneficial effects that: the invention utilizes the flexible polymer film and the microspheres with the particle size of 250-550nm to prepare the double-layer 3D photonic crystal with the 2D optical characteristic. The preparation method has the advantages of simple and convenient process and mild conditions. The obtained new double-layer photonic crystal optical switch film device has good flexibility and never fades. The thin film also has the angular dependence of 2D photonic crystals. Rotating the double-layer photonic crystal can obtain a color pattern with periodic reproducibility. Rich color changes can be achieved by changing only the light source or the viewing angle. The light path can be switched on and off without external environmental condition stimulation, and a diffraction band covering the full visible spectrum can be obtained under the non-specular reflection condition. The diffraction bands are discontinuous and there is a periodic reproducibility of 30 and 60. The on-off of the hexagonal periodic light path can be realized at one side of the light source only by rotating the double-layer photonic crystal film. The prepared polymer material has good flexibility and is suitable for various curved surface devices. The method is also suitable for modifying the surfaces of various substrates, such as glass, metal, ceramics, various synthetic resin substrates and the like. The preparation cost of the film is low, the operation is simple, the film is green and environment-friendly, the universality is good, and the film has important significance in promoting the practical application of photonic crystals.

Drawings

Fig. 1 is a flow chart of a new device of the double-layer photonic crystal thin film in example 1 from left to right, and is also applicable to all the examples.

Fig. 2 is a SEM top view, an inverse opal SEM top view, a 2D reflectance spectrum at an incident angle of 57.5 ° with the detector at a 10 ° angle to the light source, and a corresponding digital photograph (inset) of the-283 nm silica microsphere template used in example 1, in which the film is blue and the scale is 1cm, in order from left to right.

Fig. 3 is a SEM top view, an inverse opal SEM top view, a 2D reflectance spectrum at an incident angle of 57.5 ° and at an angle of 10 ° between the detector and the light source, and a corresponding digital photograph (inset) of the-350 nm silica microsphere template used in example 2, in which the film is green and the scale is 1cm, in order from left to right.

Fig. 4 shows, from left to right, a SEM top view, an inverse opal SEM top view, a 2D reflectance spectrum at an incident angle of 57.5 ° with the detector forming a 10 ° angle with the light source, and a corresponding digital photograph (inset) of the silica microsphere template of 395nm used in example 3, where the film is orange and the scale is 1 cm.

FIG. 5 is a SEM top view, inverse opal SEM top view, 2D reflectance spectrum at an angle of incidence of 57.5 ° with the detector at a 10 ° angle to the light source, and corresponding digital photographs of the-441 nm silica microsphere template used in example 4, where the film is red and the scale is 1 cm.

FIG. 6a is a 2D photonic band gap spectrum of the double-layer photonic crystal film in example 3, when viewed from the thinner side of the double-layer photonic crystal film, rotating one revolution along the film plane. FIG. 6b is a 2D photonic band gap spectrum when the double-layer photonic crystal film rotates one circle along the film plane in example 3 from the thicker side of the double-layer photonic crystal film.

FIG. 7a is a tensile strain curve of the two-layer photonic crystal film of example 3. Fig. 7b is a spectrum test experiment of the double-layer photonic crystal film in example 3 after being bent 300 times, and the bending experiment shows that the structural color of the film has good stability.

FIG. 8a is a 2D diffraction image of inverse opal observed from the thicker side of the double-layer photonic crystal film in example 3. Fig. 8b is a 2D diffraction image obtained by rotating the double-layer inverse opal photonic crystal film by 30 ° along the film plane under the condition of fig. 8 a. FIG. 8c is a 2D diffraction image of the inverse opal when viewed from the thinner side of the bilayer photonic crystal film in example 3. Fig. 8D is a 2D diffraction image obtained by rotating the double-layer inverse opal photonic crystal film by 30 ° along the film plane under the condition of fig. 8 c.

Fig. 9a is an inverse opal SEM cross-sectional view corresponding to the double-layer inverse opal photonic crystal template a in example 3, example 9 and example 10 and comparative example 2 and an inverse opal SEM cross-sectional view corresponding to the double-layer inverse opal photonic crystal templates a and B in comparative example 3. Fig. 9b is an SEM cross-sectional view of an inverse opal corresponding to the double-layer inverse opal photonic crystal template a in example 3 and example 9. Fig. 9c is an SEM cross-sectional view of an inverse opal corresponding to the double-layer inverse opal photonic crystal template B of example 10.

Fig. 10 is a digital photograph of the patterned silica template of example 4 as a function of angle of incidence. The light source and the camera are at the same position, and the incidence angles are respectively 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees and 65 degrees. The photograph shows a structural color transition from blue to red.

FIG. 11 is a 2D photonic band gap spectrum of the double-layer photonic crystal film in example 5, which is observed from the thicker side of the double-layer photonic crystal film containing titanium dioxide nano-microspheres, during one rotation of the double-layer photonic crystal along the film plane.

FIG. 12a is a digital photograph of the double-layer photonic crystal film rotated 90 degrees as viewed from the thinner side of the double-layer photonic crystal film in example 9. The light source and the camera are at the same position, and the incident angle is 50 degrees, and the shooting is performed once every 15 degrees. FIG. 12b is a digital photograph of the double-layer photonic crystal film rotated 90 degrees as viewed from the thicker side of the double-layer photonic crystal film in example 9. The light source and the camera are at the same position, and the incident angle is 50 degrees, and the shooting is performed once every 15 degrees.

FIG. 13a is a graph showing the relationship between the 2D reflectance spectrum of the underlayer and the thickness of the underlayer when the angle of incidence is 57.5 ℃ and the detector is at an angle of 10 ℃ to the light source, when viewed from the thinner side of the bilayer photonic crystal film in example 9 and comparative examples 2, 3, and 10. FIG. 13b is a graph of the 2D reflectance spectrum of the bottom layer versus the thickness of the top layer at an angle of incidence of 57.5 and a detector at a 10 angle to the light source, as viewed from the thicker side of the bilayer photonic crystal films in example 9 and comparative examples 2, 3, and 10.

Detailed Description

The following non-limiting examples are presented to enable those of ordinary skill in the art to more fully understand the present invention and are not intended to limit the invention in any way.

The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials are commercially available, unless otherwise specified.