KR20160125806A

KR20160125806A - Nanoplasmonic color filter

Info

Publication number: KR20160125806A
Application number: KR1020150056790A
Authority: KR
Inventors: 박성주; 홍상현; 김재준; 이효주
Original assignee: 광주과학기술원
Priority date: 2015-04-22
Filing date: 2015-04-22
Publication date: 2016-11-01

Abstract

Provided is a nanoplasmonic color filter which has a material coated on a transparent substrate wherein the material is selected among a metal nanoparticle, a metal nanocube, a metal nanowire, a metal nanotube, a metal porous nanotube, and a combination thereof. According to the present invention, a kind, a size, a concentration (or density), and the like of metal of the metal nanoparticle, the metal nanocube, the metal nanowire, the metal nanotube or the metal porous nanotube are adjusted to optimize an absorption wavelength through local plasmon resonance, thereby providing the color filter having improved transmittance and simplifying processes and enabling large area processes through a solution process.

Description

[0001] NANOPLASMONIC COLOR FILTER [0002]

The present invention relates to a nanoplasmonic color filter. More specifically, the present invention relates to a color filter using plasmon resonance of metal nanoparticles, metal nanocubes, metal nanowires, metal nanotubes, or metal porous nanotubes.

The color filter is a key component for realizing colors in displays such as LCD and OLED and CMOS image sensors used in digital cameras. A color filter passes only light of a specific color among white light, and a plurality of filter regions corresponding to pixels of the image panel are arranged on a substrate. Each of the plurality of filter regions has, for example, a sub filter region of red (R), green (G), and blue (B). A color filter having a high color purity and a high light transmittance is required to realize a high quality image quality in a display device.

As in Patent Document 1, color filter technology using dye or pigment material is generally commercialized. However, dye or pigment materials have poor heat stability and long life.

Therefore, researches on nanoplasmonic applied color filter technology using metal grid structure have been actively conducted at home and abroad. Nanoplasmonic color filters have higher transmittance than color filters using conventional dyes / pigments, and have excellent thermal stability, and studies are underway to improve the transmittance to 40%. The development of color filter technology with high transmittance will contribute to the commercialization of low-power displays, imaging sensors, and lighting technologies. In order to realize a nanoplasmonic color filter, it is necessary to fabricate a metal lattice structure. Therefore, a nano patterning process which is complicated and applied only to a local area is essential. Also, the transmittance is 20 ~ 30% There is a problem that it can not be done. In addition, since the metal grid structure has a one-dimensional structure, there is a problem that the light of the backlight unit (BLU) is polarized and a viewing angle problem occurs, so that there is a problem to be overcome in application to a commercialized product.

Korean Patent Publication No. 2011-0069413

One aspect of the present invention is to provide a color filter which is excellent in stability against heat, excellent in color reproducibility, capable of selectively absorbing and passing light according to wavelength, and capable of simplifying a manufacturing process by a solution process and a large- present.

However, the problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

In order to accomplish the above object, one aspect of the present invention provides a method of fabricating a light emitting device, comprising: forming a light emitting layer on a transparent substrate, the metal nanotube being selected from the group consisting of metal nanoparticles, metal nanocubes, metal nanowires, metal nanotubes, metal porous nanotubes, The present invention provides a nanoplasmonic color filter in which a material is coated.

According to the present invention, it is possible to optimize the absorption wavelength through local plasmon resonance by controlling the kind, size, concentration (or density) of metal of metal nanoparticles, metal nanocubes, metal nanowires, metal nanotubes or metal porous nanotubes A color filter having improved transmittance can be provided, and a process can be simplified through a solution process and a large area process can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view of a color filter (a) comprising metal nanoparticles or metal nanocubes coated on a transparent substrate, a metal nanowire, a metal nanotube, or a color including metal porous nanotubes Filter (b), metal nanoparticles or metal nanocubes; And a color filter (c) comprising a combination of metal nanowires, metal nanotubes or metal porous nanotubes.
FIG. 2 is a view showing an example of the implementation of magenta color by the navy blue color mixing method.
3 (a) to 3 (c) are diagrams showing the implementation colors according to the types of color filters by the nano-color mixing method using metal nanoparticles or metal nanocubes.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. It should be understood, however, that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, the same reference numbers are used throughout the specification to refer to the same or like parts.

Throughout this specification, when a member is "on " another member, it includes not only when the member is in contact with the other member, but also when there is another member between the two members.

Throughout this specification, when an element is referred to as "including " an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise. The terms "about "," substantially ", etc. used to the extent that they are used throughout the specification are intended to be taken to mean the approximation of the manufacturing and material tolerances inherent in the stated sense, Accurate or absolute numbers are used to help prevent unauthorized exploitation by unauthorized intruders of the referenced disclosure. The word " step (or step) "or" step "used to the extent that it is used throughout the specification does not mean" step for.

Throughout this specification, the term "combination thereof" included in the expression of the machine form means one or more combinations or combinations selected from the group consisting of the constituents described in the expression of the machine form, And the like.

The use of terms such as " comprising "or" comprising "in this specification should not be construed as necessarily including the various elements or steps described in the specification, including some or all of the steps Or may further include additional components or steps.

The present invention relates to a color filter technique that utilizes local plasmon resonance phenomenon of a metal surface using metal nanoparticles, metal nanocubes, metal nanowires, metal nanotubes, or metal porous nanotubes. It is possible to control the local surface plasmon resonance wavelength region by a method of laminating or mixing one or more kinds of metal nanoparticles, metal nanocubes, metal nanowires, metal nanotubes, and / or metal porous nanotubes, We propose a color filter fabrication technique that can be applied to display, imaging sensor, lighting technology, etc. by using wavelength change.

Specifically, the color filter provided in the present invention includes a transparent substrate, a material selected from the group consisting of metal nanoparticles, metal nanocubes, metal nanowires, metal nanotubes, metal porous nanotubes, Metal nanomaterials "). The materials may be coated as a single layer on the transparent substrate, or may be in a multilayered laminated form.

The transparent substrate may be a transparent glass substrate or a transparent plastic substrate. The transparent plastic substrate may be, for example, a flexible transparent substrate including PET (polyethylene terephthalate) or PEN (polyethylene naphthalate).

The material selected from the group consisting of the metal nanoparticles, the metal nanocubes, the metal nanowires, the metal nanotubes, the metal porous nanotubes, and combinations thereof is directly coated on the transparent substrate by solution coating or vapor deposition, (Arranged) on the upper surface of the substrate.

When the solution coating method is used, a solution containing a metal nanomaterial or a solution of a metal nanomaterial can be formed by spray coating, roll-to-roll coating, printing, spin coating, dip coating, mist coating or inkjet method.

According to the deposition method, a plasma enhanced chemical vapor deposition (PECVD) method, a low pressure chemical vapor deposition (LPCVD) method, or a sputtering method may be used. But is not limited to.

In the case of using the solution coating method or the vapor deposition method, it is advantageous in that the large-area coating process is easier than the nano patterning process and the base equipment is easily constructed and operated for the manufacturing process.

One layer (single layer or single layer) may be formed on the transparent substrate by the metal nanomaterial. The metal nanoparticles, metal nanocube metal nanowires, metal nanotubes, and / or metal porous nanotubes have a property of absorbing light of a specific wavelength by a local surface plasmon, and selectively absorb light to transmit the remaining light The target light) can be transmitted.

Surface plasmons are localized plasmon on the metal thin film surface, and correspond to electromagnetic waves traveling along the interface between the metal thin film and the dielectric. Surface plasmon phenomenon refers to a phenomenon in which light of a specific wavelength and free electrons on the surface of a metal thin film resonate to cause light of a specific wavelength to propagate along the surface when light is incident on the surface of the metal thin film. Surface plasmons are collective vibrations of free electrons induced on the metal film surface by the electric field of incident light, which means collective vibration of free electrons occurring on the surface of the metal film, and exist locally on the surface of the metal film.

In the case of a metal nanomaterial having a local surface plasmon characteristic, when an arbitrary light source is incident, it absorbs and scatters light of a specific wavelength band among arbitrary light sources. At this time, incident light is transmitted along the surface without being changed into reflected light. Since these properties are selectively exhibited depending on the type, shape, size, coating condition, coating thickness and dielectric constant of the coating material, it is possible to manufacture a metal nanomaterial having a filtering function for a specific light source wavelength, By forming the nanomaterial on the transparent substrate, the color filter of the present invention can be manufactured.

Among the metal nanomaterials, the metal nanoparticles or the metal nanowires may have a core-shell structure in which the different kinds of metal materials form a core and a shell, respectively, or an alloy structure in which the different types of metal materials are alloyed. The metal nanomaterial is superior in heat stability to a pigment or a dye material.

According to an embodiment of the present invention, the nanoplasmonic color filter of the present invention should absorb red and transmit blue and green in order to realize cyan color. (Ii) a metal nanowire having a diameter of 5 nm (diameter) x 20 nm (length) or more and 10 nm (diameter) x 40 nm (length) or less (Iii) a method of using a core-shell structure in which Au is coated on the Ag core of 80 to 120 nm (diameter) with the metal nanowire, or (iv) a method of using the metal nanowire to form an alloy structure of Ag and Au And the like.

When the metal nanoparticles are used alone, the size of the nanoparticles for absorbing the red wavelength region is increased to 100 nm or more and the half width of the absorption wavelength is widened. However, the nanoparticles having a diameter of 5 nm (diameter) Or more and an Au nanowire of 10 nm (diameter) x 40 nm (length) or less is used, this problem can be solved.

According to another embodiment of the present invention, the nanoplasmonic color filter of the present invention must absorb green and transmit blue and red in order to realize magenta color. (I) a method of using Au having a size of 5 to 120 nm as the metal nanoparticles or using an alloy structure of Ag and Au, (ii) a method in which Au having a diameter of 5 nm (diameter) x 20 nm (Iii) a method of using a core-shell structure in which Au is coated on the Ag core of 80 to 120 nm (diameter) with the metal nanowire, or (iv) a method of using an alloy of Ag and Au as the metal nanotube or the porous nanotube Structure can be used.

According to another embodiment of the present invention, the nanoplasmonic color filter of the present invention must absorb blue and transmit green and red in order to realize a yellow color. This (ⅰ) the metal method using a 10 ~ Ag of 100nm in size to nanoparticles, (ⅱ) with a TiO ₂ of 10 ~ 100nm (thickness) to the Ag core of 100 ~ 150nm (the diameter) to the metal nanowires coated cores - shell structure, or (iii) a method using Ag with a diameter of 40 to 80 nm as the metal nanowire, or a method using a core-shell structure in which an Ag core is coated with Au.

Fig. 1 shows an exemplary schematic diagram of a color filter according to the present invention.

1 (a) shows a color filter including metal nanoparticles or metal nanocubes coated on a transparent substrate, and FIG. 1 (b) shows a color filter including metal nanowires, metal nanotubes, or metal porous nanotubes 1 (c) shows metal nanoparticles or metal nanocubes; And a color filter comprising a combination of metal nanowires, metal nanotubes or metal porous nanotubes.

The color filters use a local surface plasmon phenomenon, which is a collective vibration phenomenon of free electrons located on the surface of a metal nanomaterial, absorbs a plasmon resonance wavelength region in white light emitted from a backlight unit (BLU) Cyan-Magenta-Yellow (CMY) type color filter can be implemented by Subtractive Color Mixture using light. CMY (Cyan, Magenta, Yellow) color is a complementary color relation with RGB (Red, Green, Blue) color in the visible light region and unlike the additive color filter (ACF) SCF (Subtractive Color Filter) method absorbs one band and implements color (CMY), so it transmits about twice as much light as the additive color filter (ACF) method, (color signal).

Fig. 2 shows an example of implementation of magenta color by the navy blue color mixing method.

That is, when the green light is absorbed by the white light emitted from the backlight unit BLU, the blue light and the red light are transmitted, and magenta color is realized by the combination.

In the conventional RGB method using the color mixture, the light transmittance is 20 ~ 30% level by blocking two colors other than the color represented by the RGB color filter. On the other hand, the CMY system can absorb light of one kind, and can express light by mixing two types of transmitted light to have a light transmittance of about 2 times, so that a light transmittance characteristic of 70% or more can be secured. Excellent color reproducibility can be realized. Due to the high light transmittance, excellent color reproduction performance of commercialized products such as high brightness, low power display, imaging sensor, and illumination can be realized. This CMY type display is expected to be useful in publishing, art, and design fields.

Wherein the metal selected from the group consisting of the metal nanoparticles, the metal nanocubes, the metal nanowires, the metal nanotubes, the metal porous nanotubes, and combinations thereof is selected from the group consisting of Au, Pt, Pd, Ir, Rh, And may be one or more selected from the group consisting of Al, Cu, Te, Bi, Pb, Fe, Ce, Mo, Nb, W, Sb, Sn, V, Mn, Ni, Co, Zn, But is not limited to. That is, it may be a metal nano material having a surface composed of a pure metal or an alloy including at least one of the above-mentioned metal elements. The metal components can perform a function of absorbing a specific wavelength using a surface plasmon absorption wavelength.

The material selected from the group consisting of the metal nanoparticles, the metal nanocubes, the metal nanowires, the metal nanotubes, the metal porous nanotubes, and combinations thereof is a core-shell structure or an alloy structure in which the surface thereof is coated with a dielectric material .

The dielectric material is a material for preventing oxidation and uniform dispersion of the metal located in the core.

These dielectric materials may be selected from the group consisting of silicon dioxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), silicon nitride (SiN _x ), zinc selenide (ZnSe), zinc oxide (ZnO), zirconium oxide (ZrO ₂ ) ₂ ), and combinations thereof. However, the present invention is not limited thereto.

When the dielectric material is coated on the metal nanomaterial, the absorption wavelength of the surface plasmon can be shifted depending on the dielectric constant of the coating material. In the present invention, by appropriately selecting a dielectric having a different dielectric constant, the position of the local surface plasmon absorption wavelength can be transferred to a desired wavelength position. Further, in the present invention, by changing parameters such as shape, size, volume ratio or density of the metal nanomaterial, the position of the surface plasmon absorption wavelength can be transferred to a desired position.

By absorbing a specific wavelength at the surface plasmon absorption wavelength of the metal nanomaterial or the plasmon absorption wavelength transferred by the dielectric, excellent transmittance and color reproducibility can be exhibited.

In the color filter using the metal nanomaterial according to the present invention, the shape, size, concentration and thickness of the dielectric material (i.e., thickness of the dielectric shell) of the metal nanomaterial are not particularly limited, As shown in FIG.

FIGS. 3 (a) to 3 (c) illustrate examples of a filter implementing various colors by controlling the type and size of metal nanoparticles or metal nanocubes.

In the case of the blue filter absorbing the blue wavelength region, the silver nanoparticles are adjusted to have a size of 20 nm and 40 nm to absorb the blue region and serve as a filter to be transmitted in the green and red regions This is possible. The green filter that absorbs the green wavelength region absorbs the green region by controlling the size of the gold nanoparticle to 50 nm and absorbs the blue region as the filter that is transmitted in the blue region and the red region. Role is possible. In the case of a red filter that absorbs a red wavelength region, the size of the gold nanoparticles is greater than 100 nm, or the reflective index of the dielectric material is greater than air, It is possible to produce a filter capable of absorbing only the red region.

Also, by adjusting the density of the metal nanomaterial, it is possible to adjust the transmittance in the absorption region to be close to 0%, thereby ensuring excellent performance of the filter.

As described above, the color filter according to the present invention can effectively absorb a desired wavelength by using a metal nanomaterial that absorbs a specific wavelength by using the absorption wavelength of the surface plasmon. In addition, specific wavelengths can be absorbed by controlling the shape, type, size, or volume content of the metal nanomaterials, or by transferring the local surface plasmon absorption wavelength to a desired wavelength location through coating or dielectric lamination with a selected dielectric material .

As described above, the light transmittance and the color reproducibility can be improved by absorbing a specific wavelength using the absorption wavelength due to the local surface plasmon phenomenon of the metal nanomaterial or the transition absorption wavelength due to the dielectric.

Claims

A nanoplasmonic color filter comprising a transparent substrate coated with a material selected from the group consisting of metal nanoparticles, metal nanocubes, metal nanowires, metal nanotubes, metal porous nanotubes, and combinations thereof.

The method according to claim 1,
Wherein the material is in the form of a single layer or a multilayer stacked on the transparent substrate.

The method according to claim 1,
The material selected from the group consisting of the metal nanoparticles, the metal nanocubes, the metal nanowires, the metal nanotubes, the metal porous nanotubes, and combinations thereof is a core-shell structure or an alloy structure whose surface is coated with a dielectric material , Nanoplasmonic color filters.

The method according to claim 1,
Wherein the metal selected from the group consisting of the metal nanoparticles, the metal nanocubes, the metal nanowires, the metal nanotubes, the metal porous nanotubes, and combinations thereof is selected from the group consisting of Au, Pt, Pd, Ir, Rh, Wherein at least one selected from the group consisting of Al, Cu, Te, Bi, Pb, Fe, Ce, Mo, Nb, W, Sb, Sn, V, Mn, Ni, Co, Zn, Monic Color Filter.

The method of claim 3,
It said dielectric material is silicon dioxide (SiO _2), aluminum oxide (Al ₂ O _3), silicon nitride (Si ₃ N _4), zinc selenide (ZnSe), zinc (ZnO), zirconium oxide (ZrO _2), titanium oxide (TiO2), and combinations thereof. &Lt; _{RTI ID} = 0.0 > 8. < / RTI >

The method according to claim 1,
Wherein the cyan color is realized by using Au having a size of 100 to 200 nm as the metal nanoparticles.

The method according to claim 1,
Wherein the metal nanowire realizes a cyan color by using Au having a diameter of 5 nm (diameter) x 20 nm (length) or more and 10 nm (diameter) x 40 nm (length) or less.

The method according to claim 1,
Wherein the cyan color is realized by using a core-shell structure in which Au is coated on the Ag core of 80 to 120 nm (diameter) with the metal nanowire.

The method according to claim 1,
Wherein the cyan color is realized by using the alloy structure of Ag and Au as the metal nanotube.

The method according to claim 1,
The nanoplasmonic color filter realizes magenta color by using Au having a size of 5 to 120 nm as the metal nanoparticles or using an alloy structure of Ag and Au.

The method according to claim 1,
Wherein the metal nanowire implements magenta color by using Au of 5 nm (diameter) x 20 nm (length) or less.

The method according to claim 1,
Wherein the magenta color is realized by using a core-shell structure in which Au is coated on the Ag core of 80 to 120 nm (diameter) with the metal nanowire.

The method according to claim 1,
Wherein the metal nanotube or the porous nanotube realizes a magenta color by using an alloy structure of Ag and Au.

The method according to claim 1,
Wherein the metal nanoparticles realize yellow color by using Ag having a size of 10 to 100 nm.

The method according to claim 1,
Wherein a yellow color is realized by using a core-shell structure in which TiO ₂ is coated with 10 to 100 nm (thickness) of Ag core of 100 to 150 nm (diameter) with the metal nanowire.

The method according to claim 1,
Wherein the metal nanowire uses Ag of 40-80 nm (diameter) or embodies a yellow color by using a core-shell structure in which an Ag core is coated with Au.

The method according to claim 1,
Wherein the material selected from the group consisting of the metal nanoparticles, the metal nanocubes, the metal nanowires, the metal nanotubes, the metal porous nanotubes, and combinations thereof is coated on the transparent substrate by a solution coating method or a vapor deposition method. Nano Plasmonic Color Filter.