KR100426961B1 - Manufacturing Method for Photonic Crystals Using Self-assembled Particles on Solvent Surface - Google Patents

Abstract

The present invention is a method for producing photonic crystal using nanoparticles,

Evenly dispersing certain nanoparticles having an effective density less than that of the solvent in the solvent, evaporating the solvent to self-assemble the particles onto the solution surface, and transferring the self-assembled particles onto the substrate. Disclosed is a method for producing a photonic crystal characterized by the above-mentioned.

According to the above structure, there is no limitation in particle size, there are few defects, and it is possible to produce photonic crystals uniformly in a large area within a short time, and thus separation membranes of lasers, piezoelectric sensors, actuators, and chromatography that require photonic crystals are required. , A catalyst carrier, an optical integrated circuit, an optical filter, an optical sensor, a display element, and the like are very useful.

Description

Manufacturing Method for Photonic Crystals Using Self-assembled Particles on Solvent Surface

The present invention is a method of manufacturing a photonic crystal using nanoparticles, and more specifically, the photonic crystal used in an optical integrated circuit, an optical filter, a laser, a sensor, or the like using magnetic levitation of the particles due to density difference and capillary force between the particles. A method for producing on the surface of a solvent.

Photonic crystals can be classified into photolithography, ion beam etching, and polymer nanoparticles using a technique used in a conventional semiconductor process.

The production of photonic crystals through conventional photolithography and ion beam etching has sophisticated advantages, but the disadvantage is that the associated costs are high and require a lot of time.

On the other hand, the method of manufacturing photonic crystals using polymer nanoparticles has the advantage of making photonic crystals inexpensively because it does not require additional equipment, but it is possible to manufacture photonic crystals over a large area in a short time and to produce sophisticated photonic crystals. No drawbacks are noted.

Therefore, in the field of manufacturing photonic crystals using polymer nanoparticles, the technique of relatively small defects and the ability to stack photonic crystals in a large area in a short time is the most important and prior task.

The production of photonic crystals using polymer nanoparticles is based on the precipitation method by gravity [H. Miguez et al, Adv. Mater. 10, 480 (1998)], vertical precipitation method [P. Jiang et al, Chem. Mater. 11, 2132 (1999)], vertical precipitation method through temperature distribution [Y.A. Vlasov et al, Nature (London) 414, 289 (2001), J. D. Joannopoulos, Nature (London) 414, 257 (2001)], electrophoresis [A.L. Rogach et al, Chem. Mater. 12, 2721 (2000).

Gravity precipitation method is the first known method that takes advantage of the phenomenon that the particles are precipitated by the gravity, and self-assembly when the solution in which the polymer particles and silica nanoparticles are dispersed for a long time. As a result, a large amount of time is required in manufacturing the photonic crystal, and a uniform photonic crystal without defects in a large area cannot be obtained.

In the vertical precipitation method, if a substrate having affinity with a solution in a vertical direction is placed in a solution in which polymer particles and silica nanoparticles are dispersed, the solution is distorted by the interfacial tension at the surface of the substrate, and the nanoparticles The alignment is based on the principle that the solvent is deposited on the substrate upon evaporation. This method has the advantage of obtaining uniform photonic crystals with relatively few defects in a relatively large area, but has a disadvantage in that it is not suitable for a large particle size and requires a relatively long time.

In recent years, a technique of improving the method and giving a temperature distribution to a substrate to increase the particle size has also been reported. However, this method has the disadvantage of requiring auxiliary equipment to control the temperature distribution.

Electrophoresis has also been reported in which surface-charged nanoparticles are sandwiched between electrodes and subjected to an electric field to deposit photonic crystals on the electrodes. This method has the advantage of being able to accumulate photonic crystals in a short time, but is not suitable for producing defect-free photonic crystals.

An object of the present invention is to solve the problems pointed out in the production of photonic crystals using the conventional polymer nanoparticles, there is no limitation on the size of the particles, there are few defects, and the photonic crystals are uniformly distributed in a large area within a short time It is to provide a novel manufacturing method that can be produced.

1 is a principle diagram for explaining the manufacturing process of the photonic crystal according to the present invention

2 is an electron scanning microscope observation result of the photonic crystal (228 nm) prepared by the present invention

3 is an electron scanning microscope observation result of the photonic crystal (500nm) prepared by the present invention

4 is an electron scanning microscope observation result of the photonic crystal (900nm) prepared by the present invention

Fig. 5 shows the results of electron scanning microscopy of photonic crystals (228 nm) on the solvent surface with temperature (60 ° C.).

FIG. 6 shows the results of electron scanning microscopy of photonic crystals (228 nm) on the solvent surface with temperature (40 ° C.)

FIG. 7 shows the results of electron scanning microscopy of photonic crystals (228 nm) on the solvent surface with temperature (30 ° C.)

8 is a photonic band gap graph according to the prior art.

The present invention is a method for producing photonic crystal using nanoparticles,

Uniformly dispersing certain nanoparticles having an effective density less than that of the solvent in the solvent, evaporating the solvent to self-assemble the particles on the surface of the solution, and moving the self-assembled particles onto the substrate. It includes a method for producing photonic crystals.

1 is a principle diagram illustrating a manufacturing process of a photonic crystal according to the present invention.

According to this, predetermined nanoparticles having a smaller effective density than the solvent are uniformly dispersed in the solvent, and when the solvent is forcibly evaporated, the particles float on the surface of the solvent, and the floating particles are self-assembled by capillary force. Is showing.

Since the effective density of the self-assembled particles is small compared to the solvent, they can remain floating and accumulate broadly and evenly on the surface of the solvent.

Illustrative conditions for the self-assembly process are as follows.

=

From above Is the effective density of the particles, Where is the density of the solvent, r is the radius of the dispersed particles, N is the number of particles on one side of the particle self-assembled in two dimensions, Means the density of the dispersed particles.

Examples of the representative particles that satisfy the above conditions include polystyrene particles dispersed in water. The density of polystyrene particles is 1.05 g / cm ³ and the density of water is 1.0 g / cm ³ . The density of one polystyrene particle is greater than water, but as the water evaporates, the effective density of the polystyrene particles self-assembled on the water surface becomes smaller than water. Thus, the polystyrene particles self-assembled on the surface of the water will float, and the above process is repeated to form photonic crystals.

Examples of the particles usable in the present invention are not particularly limited, but in addition to the polystyrene, polyalphamethylstyrene, polyacrylate, polymethyl methacrylate, polybenzyl methacrylate, polyphenyl methacrylate, poly1-methylcyclohexyl Methacrylate, polycyclohexyl methacrylate, polychlorobenzyl methacrylate, poly1-phenylethyl methacrylate, poly1,2-diphenylethyl methacrylate, polydiphenylmethyl methacrylate, polyperfuryl And at least one member selected from the group of homopolymers consisting of methacrylate, poly1-phenylcyclohexyl methacrylate, polypentachlorophenyl methacrylate, and polypentabromophenyl methacrylate.

It is also possible to use copolymers in addition to the above homopolymers. Examples of these copolymers include methyl methacrylate (MMA) -benzyl methacrylate copolymer (BMA), styrene-acrylonitrile (SAN) copolymer, MMA-TFEMA (2,2,2-trifluoroethylmethacryl). Copolymer), MMA-PFPMA (2,2,3,3,3-pentafluoropropylmethacrylate) copolymer, MMA-HFIPMA (1,1,1,3,3,3-hexafluoroiso Methacrylate) copolymer, MMA-HFBMA (2,2,3,3,4,4,4-heptafluorobutylmethacrylate) copolymer, TFEMA-PFPMA copolymer, TFEMA-HFIPMA copolymer, styrene- At least one member selected from the group consisting of methyl methacrylate (SM) copolymer, and TFEMA-HFBMA copolymer.

The solvent is required to be selected from materials which are larger than the effective density of the particles of choice. Usable as such solvents, for example, water, methanol, ethanol, ethylene glycol, glycerol, perfluorodecalin, perfluoromethyldecalin, perfluorononane, perfluoroisoacid, perfluorocyclohexane, perfluoro1,2-dimethyl It includes one selected from the group consisting of cyclohexane, perfluoro2-methyl2-pentene and perfluorokerosene.

The evaporation process of the solvent is usually required to be performed below the boiling point of the solvent. The faster the evaporation rate of the solvent, the shorter the time taken for photonic crystals to form on the surface of the solvent. Can cause problems. In the present invention, the optimum evaporation conditions for the crystal formation are different depending on the type of particles and the solvent used, and these are merely matters that can be easily selected by those skilled in the art from the description of the present invention, and thus no specific specification of these conditions is required. .

Through the self-assembly process as described above, particles that are broadly and uniformly stacked on the surface of the solvent are then transferred to the substrate. In this case, the vertical precipitation method is used to transfer the photonic crystals stacked on the solvent to the substrate by simply placing the substrate vertically or at an angle in the solution. Or by forming a photonic crystal on the surface of the solvent, or simply by evaporating the solvent to move the photonic crystal on the substrate, and the like.

The present invention includes pores of self-assembled particles through the above process, including semiconductors (for example, all commonly used semiconductors such as Si, CdS, Cdse, GaAs, and the like), metals (eg, Ag, It includes, but is not limited to, all commonly used metals such as Au, Al, and the like, metal oxides (including, but not limited to, all common metal oxides such as aluminum oxide and iron oxide), or organic materials (eg, Poly (para-phenylenevinylene), polythiophene, poly (para-phenylene), polyquinoline, polypyrrole, polyacetylene, or polyfluorene and the respective derivatives of organics, and are not particularly limited). Filling with at least one material includes a method for producing a photonic crystal further included.

In addition, the present invention may introduce a template process to obtain a reversed phase for use in various devices. That is, the present invention includes a method of manufacturing a photonic crystal further comprises the step of removing the template from the photonic crystal filled with pores as described above.

Photonic crystals produced through the above process are provided for the manufacture of lasers, piezoelectric sensors, actuators, chromatographic separators, catalyst carriers, optical integrated circuits, optical filters, optical sensors, display devices, and the like.

Hereinafter, the content of the present invention will be described in more detail with reference to Examples. However, these examples are only presented to understand the content of the present invention, and the scope of the present invention should not be construed as being limited to these embodiments.

Example 1 Preparation of Photonic Crystal on Solvent Surface According to Particle Size I

Water and polystyrene were used as pairs of particles with similar densities to solvents and lower effective densities than solvents for self-assembly.

After dispersing polystyrene 228 nm size particles in water at 5% by weight, the solution was placed in a 90 ° C. convection oven. After about 10 minutes, the polystyrene particles self assembled on the surface of the water. Through this procedure, photonic crystals of polystyrene 228 nm size were obtained on the water surface, and the photonic crystals were transferred to the substrate by the vertical precipitation method.

This can be confirmed through the electron scanning microscope observation result of FIG. 2.

Example 2 Preparation of Photonic Crystal on Solvent Surface According to Particle Size II

After dispersing the polystyrene 500 nm size particles in water at 5% by weight, the solution was placed in a 90 ° C. convection oven. After about 10 minutes, the polystyrene particles self assembled on the surface of the water. Through the above procedure, a photonic crystal having a polystyrene size of 500 nm was obtained on the surface of water, which can be confirmed by electron scanning microscope observation of FIG. 3.

Example 3 Preparation of Photonic Crystal on Solvent Surface According to Particle Size III

The polystyrene 900 nm sized particles were dispersed in water at 5% by weight, and then the solution was placed in a 90 ° C. convection oven. After about 10 minutes, the polystyrene particles self assembled on the surface of the water. Through the above procedure, photonic crystals having a polystyrene size of 900 nm were obtained on the water surface, which can be confirmed by electron scanning microscope observation of FIG. 4.

Example 4 Preparation of Photonic Crystals on Solvent Surface by Temperature I

After dispersing polystyrene 228 nm size particles in water at 5% by weight, the solution was placed in a convection oven at 60 ° C. After 20 minutes, the polystyrene particles self assembled on the surface of the water. Through the above procedure, a photonic crystal having a polystyrene size of 228 nm was obtained on the surface of water, which can be confirmed by electron scanning microscope observation of FIG. 5.

Example 5 Preparation of Photonic Crystal on Solvent Surface by Temperature II

After dispersing polystyrene 228 nm size particles in water at 5% by weight, the solution was placed in a 40 ° C. convection oven. After 30 minutes, the polystyrene particles self-assembled on the surface of the water. Through the above procedure, a photonic crystal having a polystyrene size of 228 nm was obtained on the surface of water, which can be confirmed by electron scanning microscope observation of FIG. 6.

Example 6 Preparation of Photonic Crystals on Solvent Surface with Temperature III

After dispersing polystyrene 228 nm size particles in water at 5% by weight, the solution was placed in a convection oven at 30 ° C. After 60 minutes, the polystyrene particles self-assembled on the surface of the water. Through the above procedure, a photonic crystal having a polystyrene size of 228 nm was obtained on the surface of water, which can be confirmed by electron scanning microscope observation of FIG. 7.

Example 7 Preparation of Template I

After the photonic crystal was obtained on the transparent electrode (ITO: Indium Tin Oxide) using the method of Example 1 and immersed in an AgNO ₃ aqueous solution, the Ag cation was reduced from the photonic crystal pore to Ag using the photonic crystal as the cathode and the aluminum plate as the anode. . After filling the pores of the photonic crystal with silver through the above process, the photonic crystal was immersed in toluene to melt polystyrene to prepare a template.

Example 8 Preparation of Template II

After the photonic crystal was prepared by the method of Example 1, 3 nm gold (Au) particles were filled between the pores of the photonic crystal. After filling, the polystyrene was burned at 500 degrees to prepare a template.

Example 9 Preparation of Template III

After the photonic crystal was prepared by the method of Example 1, 5 nm of CdSe was charged, and then, polystyrene was burned at 500 degrees to prepare a template.

Example 10 Preparation of Template IV

After the photonic crystal was prepared by the method of Example 1, polyparaphenylene vinylene (PPV) was charged, and then, toluene was immersed to dissolve polystyrene to prepare a template.

Comparative Example 1

After dispersing polystyrene 228 nm size particles in water at 5% by weight, the solution was placed in a 25 ° C. free convection oven. After two days of observation, it was confirmed that the polystyrene particles did not self-assemble on the surface of the water. This is due to the fact that the particles settle to the bottom by gravity and it takes at least two days for all the water to evaporate. In addition, it was observed that the photonic crystals produced through the above process were shallower in photonic bandgap than the photonic crystals produced by the present invention (FIG. 8). The photonic bandgap reflects the crystal state of the photonic crystal, and the deeper the crystal alignment, the deeper it appears.

Comparative Example 2

After dispersing the particles of polystyrene 500 nm size in water by 1% by weight, the solution was placed in an oven at 25 ° C., and the photonic crystal was stacked on the substrate by directly placing the substrate vertically in the solution. According to the present invention, the substrate is placed in a solution after the photonic crystal is formed on the water surface, but there is a difference in that the substrate is placed before the photonic crystal is formed on the water surface. In this case, it can be observed that uniform photonic crystals are not produced on the substrate because the settling speed of the particles is faster than that on the substrate (Y.A. Vlasov et al, Nature (London) 414, 289 (2001), See JD Joannopoulos, Nature (London) 414, 257 (2001).

Comparative Example 3

After dispersing 500 nm polystyrene particles in 5% by weight in ethanol, the solution was placed in a 60 ° C. convection oven and after 20 minutes, the surface of the ethanol was examined and the photon crystals did not accumulate on the surface. .

According to the present invention, there is no limitation in particle size, there are few defects, and photonic crystals can be produced uniformly in a large area within a short time, and thus separation membranes of lasers, piezoelectric sensors, actuators, and chromatography that require photonic crystals are required. , A catalyst carrier, an optical integrated circuit, an optical filter, an optical sensor, a display element, and the like are very useful.

Claims (8)

In the method for producing photonic crystal using nanoparticles, Evenly dispersing certain nanoparticles having an effective density less than that of the solvent in the solvent, evaporating the solvent to self-assemble the particles onto the solution surface, and transferring the self-assembled particles onto the substrate. Photonic crystal manufacturing method characterized by The method of claim 1, wherein the nanoparticles Method for producing photonic crystals characterized by the following conditions = From above Is the effective density of the particles, Where is the density of the solvent, r is the radius of the dispersed particles, N is the number of particles on one side of the particle self-assembled in two dimensions, Means the density of the dispersed particles. The method of claim 1, wherein the nanoparticles Polystyrene, polyalphamethylstyrene, polyacrylate, polymethylmethacrylate, polybenzyl methacrylate, polyphenyl methacrylate, poly1-methylcyclohexyl methacrylate, polycyclohexyl methacrylate, polychlorobenzyl meta Acrylate, poly1-phenylethyl methacrylate, poly1,2-diphenylethyl methacrylate, polydiphenylmethyl methacrylate, polyperfuryl methacrylate, poly1-phenylcyclohexyl methacrylate, poly At least one member selected from the group of homopolymers consisting of pentachlorophenyl methacrylate and polypentabromophenyl methacrylate. The method of claim 1, wherein the nanoparticles Methyl methacrylate (MMA) -benzyl methacrylate copolymer (BMA), styrene-acrylonitrile (SAN) copolymer, MMA-TFEMA (2,2,2-trifluoroethyl methacrylate) copolymer, MMA-PFPMA (2,2,3,3,3-pentafluoropropylmethacrylate) copolymer, MMA-HFIPMA (1,1,1,3,3,3-hexafluoroisomethacrylate) Copolymer, MMA-HFBMA (2,2,3,3,4,4,4-heptafluorobutylmethacrylate) copolymer, TFEMA-PFPMA copolymer, TFEMA-HFIPMA copolymer, styrene-methylmethacrylate ( SM) copolymer, and TFEMA-HFBMA copolymer is a method for producing a photonic crystal, characterized in that at least one selected from the group consisting of. The method of claim 1 wherein the solvent is Water, methanol, ethanol, ethylene glycol, glycerol, perfluorodecalin, perfluoromethyldecalin, perfluorononane, perfluoroisoacid, perfluorocyclohexane, perfluoro1,2-dimethylcyclohexane, perfluoro2-methyl Method for producing photonic crystals, characterized in that selected from the group consisting of 2-pentene, perfluorokerosene The method of claim 1, Self-assembled particles are transferred to the substrate by any method selected from the vertical precipitation method, LB method or precipitation method. The method of claim 1, Filling the pores of the self-assembled particles with at least one material selected from semiconductors, metals, metal oxides or organics. The method of claim 7, wherein The method of manufacturing a photonic crystal further comprises the step of removing the template from the photonic crystal filled with voids to obtain a reversed phase.