KR102485510B1 - A quantum dot arrangement method for photoluminescence system using electrophoresis - Google Patents

Abstract

The present invention relates to a method for arranging quantum dots for a photoluminescent system, (a) preparing non-polar quantum dots and non-polar non-conductor particles, (b) using non-polar quantum dots and non-polar non-conductor particles as polar quantum dots and Converting polar insulator particles into polar insulator particles, (c) mixing and dispersing polar quantum dots and polar insulator particles in a polar solvent, and (d) polar insulator quantum dots and polar insulators by electrophoresis Provides a method for arranging quantum dots for a photoluminescence system using electrophoresis, comprising patterning particles, wherein a plurality of polarized quantum dots are positioned to be spaced apart from each other by a plurality of polar non-conductive particles formed in plurality. do.

Description

A quantum dot arrangement method for photoluminescence system using electrophoresis}

The present invention relates to a method for arranging quantum dots for a photoluminescence system using electrophoresis, and more particularly, by dispersing polarized quantum dots and insulator particles in a polar solvent and dispersing polarized quantum dots and insulator particles in a desired pattern using electrophoresis. It relates to a method for arranging quantum dots for a photoluminescence system using electrophoresis, which is patterned and arranged.

Light-emitting diodes using quantum dots are attracting attention as a next-generation display technology because of their advantages such as excellent color reproducibility and high luminous efficiency.

Nevertheless, light emitting diode-related technology using quantum dots has difficulties in commercialization due to the absence of high-resolution array technology.

In more detail, the light source for realizing the display device is heat radiation that emits light when the polymer body is heated to a high temperature according to the principle of light emission, and luminescence that emits light by conversion of atomic or molecular energy state regardless of heat and temperature. cold light).

Among them, luminescence can be classified into electroluminescence (EL), photo-luminescence (PL), discharge-type luminescence, and chemiluminescence according to the shape of a detailed energy delivery medium.

In electroluminescence (EL), quantum dots emit light by injecting electrical energy in the form of electrons and holes from both electrodes.

In particular, in VR devices, it is essential to implement high resolution because ultra-high resolution (1200 ppi or more) must be implemented so that a screen door effect does not occur and realistic images can be implemented.

In order to solve the above problems, the present applicant uses EPD (electrophoresis deposition) to move/attach quantum dots to one electrode using a potential difference in an electric field formed in a dispersed solvent, and to one and the other electrode using alternating current (AC). We have applied for No. 10-2020-0088910 (A method for arranging polarized quantum dots using electrophoresis) that implements high resolution by arranging electroluminescent quantum dots using DEPD (dielectricphoresis deposition) technology for attaching quantum dots.

On the other hand, in the photo-luminescence (PL) system, quantum dots emit light by injecting energy of a specific wavelength in the form of photons (photons) from the outside.

At this time, as a method for arranging the quantum dots for the photoluminescent system, there are a vacuum deposition method, an inkjet printing method, a photolithography method, and the like.

However, the vacuum deposition method has low material usage efficiency, the inkjet printing method is difficult to control the thickness and uniformity of the film in a large area, and it is impossible to implement a super-high resolution display, and the photolithography method has a high density of quantum dots dispersed. There is a problem in that the reliability of the quantum dots decreases in the limitations of millbase fabrication and baking and etching processes.

Therefore, there is a need for research and development related to an array of quantum dots that can be used for photoluminescence and minimizes extinction while realizing ultra-high resolution.

(Patent Document 1) Registered Patent Publication No. 10-0219836 (1999.06.16.)

(Patent Document 2) Patent Publication No. 10-2002-0094479 (2002.12.18.)

An object of the present invention to solve the above problem is to put quantum dots and insulator particles having polarity in a polar solvent to disperse them, and to pattern the quantum dots and insulator particles in a predetermined pattern on a positive electrode substrate having an anode and a negative electrode substrate having a negative electrode. It is to provide a method of arranging quantum dots for a photoluminescence system using electrophoresis to arrange them.

The technical problem to be achieved by the present invention is not limited to the above-mentioned technical problem, and other technical problems not mentioned can be clearly understood by those skilled in the art from the description below. There will be.

The configuration of the present invention for achieving the above object is (a) preparing non-polar quantum dots and non-polar non-conductor particles; (b) converting the non-polar quantum dots and non-polar insulator particles into polar quantum dots and polar insulator particles; (c) mixing and dispersing the polarized quantum dots and the non-conductive particles having polarity in a polar solvent; and (d) patterning the polar quantum dots and the polar insulator particles using an electrophoresis method, wherein the plurality of polar quantum dots are formed in plurality of the polar insulator particles. It provides a method for arranging quantum dots for a photoluminescent system using electrophoresis, characterized in that they are positioned to be spaced apart from each other by.

In an embodiment of the present invention, the polar non-conductive particles may be characterized in that they are relatively larger than the polar quantum dots.

In an embodiment of the present invention, step (a) may include: (a1) preparing a container containing a dispersion solution and an acid compound or base compound having a mercapto functional group; (a2) injecting the non-polar quantum dots and the non-polar non-conductor particles into the container and then heating them; and (a3) reacting the dispersion solution, the acid compound or base compound having the mercapto functional group, the non-polar quantum dots, and the non-polar non-conductor particles at a predetermined temperature for a predetermined time. that can be characterized.

In an embodiment of the present invention, the step (b) may include (b1) surface-reforming the non-polar quantum dots and the non-polar non-conductor particles; (b2) washing the surface-modified quantum dots and non-conductive particles; and (b3) water-dispersing the washed quantum dots and insulator particles to produce polar quantum dots and polar insulator particles.

In an embodiment of the present invention, step (b2) may include preparing a washing container containing an organic solvent; washing by alternately dispersing and precipitating the surface-modified quantum dots and non-conductive particles in the organic solvent; and drying the washed quantum dots and non-conductive particles by at least one of natural drying and vacuum drying to remove residual solvents.

In an embodiment of the present invention, the step (b3) may include forming a quantum dot dispersion solution in which the residual solvent is removed and the non-conductive particles are dispersed in a buffer solution; removing agglomerates and impurities of quantum dots and non-conducting particles present in the dispersion solution of quantum dots and non-conducting particles by centrifugation; mixing a pH-adjusted buffer solution with the dispersion solution of quantum dots and non-conductive particles; and imparting charge to the surface-modified quantum dots and non-conductive particles by adjusting the pH.

In an embodiment of the present invention, the step (d) may include (d1) preparing a polar solvent accommodated in the accommodating unit, the polarized quantum dots dispersed in the polar solvent, and the non-conductive particles having the polarity; (d2) immersing the positive electrode substrate and the negative electrode substrate on which a predetermined pattern is formed into the polar solvent; and (d3) a power supply unit electrically connected to the positive electrode substrate and the negative electrode substrate, and applying power to the positive electrode substrate and the negative electrode substrate to form an electric field in the predetermined pattern. may be characterized by including direct current (DC) and alternating current (AC).

In an embodiment of the present invention, in the step (d), (d4) the polar quantum dots dispersed in the polar solvent and the polar non-conductor particles are set in a predetermined pattern of the positive electrode substrate and a predetermined pattern of the negative electrode substrate. Arranged in at least one of the patterns and patterned by the electrophoresis method; and (d5) taking the positive electrode substrate and the negative electrode substrate out of the polar solvent and drying them.

In an embodiment of the present invention, the polar solvent is a material capable of forming the electric field and includes water, deionized water (DIW), acetone, ether, chloroform, ethyl acetate, isopropyl alcohol (IPA), It may be characterized in that it includes at least one of hexane, benzene, and toluene.

In an embodiment of the present invention, the polarized quantum dots and the non-conductive particles having polarity may be characterized in that they exhibit either positive or negative polarity as they are dispersed by zeta potential.

In an embodiment of the present invention, the polar quantum dots and the non-conductive particles having polarity may be characterized in that they exhibit either positive or negative polarity as they are dispersed by ligand substitution.

In an embodiment of the present invention, the polar non-conductive particles may include at least one of polymer particles and ceramic particles.

The configuration of the present invention for achieving the above object provides an electroluminescent device manufactured by applying the method of arranging quantum dots for a photoluminescence system using electrophoresis according to the above.

The configuration of the present invention for achieving the above object provides a QD panel for a display manufactured by applying the method of arranging quantum dots for a photoluminescence system using electrophoresis according to the above.

The effect of the present invention according to the configuration as described above is obtained by dispersing polarized quantum dots and insulator particles in a polar solvent, patterning the quantum dots and insulator particles in a predetermined pattern on a positive electrode substrate having an anode and a negative electrode substrate having a negative electrode, and then arranging them. Accordingly, it is possible to minimize the quenching phenomenon and implement a pixel resolution of 1200ppi or higher.

The effects of the present invention are not limited to the above effects, and should be understood to include all effects that can be inferred from the detailed description of the present invention or the configuration of the invention described in the claims.

1 (a) and (b) are conceptual diagrams illustrating quantum dots used in a method for arranging quantum dots for a photoluminescence system using electrophoresis according to an embodiment of the present invention.
2 is a cross-sectional perspective view showing quantum dots used in a method for arranging quantum dots for a photoluminescence system using electrophoresis according to an embodiment of the present invention.
3 is a conceptual diagram showing a quantum dot arrangement device for a photoluminescence system used in a method for arranging quantum dots for a photoluminescence system using electrophoresis according to an embodiment of the present invention.
4 is a flowchart illustrating a method of arranging quantum dots for a photoluminescence system using electrophoresis according to an embodiment of the present invention.
5 is a conceptual diagram illustrating a process of ligand substitution of quantum dots in a method for arranging quantum dots for a photoluminescence system using electrophoresis according to an embodiment of the present invention.
6 is a graph showing photoluminescence (PL) intensity according to wavelength related to ligand substitution and zeta potential control by dispersing quantum dots used in a method for arranging quantum dots for a photoluminescence system according to an embodiment of the present invention. to be.
7 is a conceptual diagram illustrating a process of simulating and patterning polarized quantum dots and non-conductive particles in a method for arranging quantum dots for a photoluminescence system using electrophoresis according to an embodiment of the present invention.
8 is a process of realizing the final quantum dot and non-conductive particle pattern by characterizing, analyzing, and device engineering the quantum dot and non-conductive particle patterns arranged by the method of arranging quantum dots for photoluminescence using electrophoresis according to an embodiment of the present invention. It is a conceptual diagram showing
9 is a view of actually measuring quantum dots and non-conductive particle patterns arranged by the method of arranging quantum dots for a photoluminescence system using electrophoresis according to an embodiment of the present invention.
10 is a graph comparing the technical difficulty of quantum dots and non-conductive particle patterns arranged by the method of arranging quantum dots for a photoluminescence system using electrophoresis according to an embodiment of the present invention using electrophoresis with those of the prior art.

Hereinafter, the present invention will be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and, therefore, is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, when a part is said to be "connected (connected, contacted, combined)" with another part, this is not only "directly connected", but also "indirectly connected" with another member in between. "Including cases where In addition, when a part "includes" a certain component, it means that it may further include other components without excluding other components unless otherwise stated.

Terms used in this specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as "include" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1. Polarized quantum dots (100)

Hereinafter, quantum dots used in the method of arranging quantum dots for a photoluminescent system using electrophoresis according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2 .

1 (a) and (b) are conceptual diagrams illustrating quantum dots used in a method for arranging quantum dots for a photoluminescence system using electrophoresis according to an embodiment of the present invention. 2 is a cross-sectional perspective view showing quantum dots used in a method for arranging quantum dots for a photoluminescence system using electrophoresis according to an embodiment of the present invention.

Referring to (a), (b) and FIG. 2 of FIG. 1 , the quantum dot 100 for photoluminescence using electrophoresis according to an embodiment of the present invention is to manufacture a quantum dot pattern through patterning using electrophoresis. used

Conventional quantum dots mainly used cadmium, but in recent years, eco-friendly cadmium-free quantum dots (cadmium-free green quantum dots) materials have been developed and used.

The quantum dot 12 means a semiconductor nanocrystal having a quantum confinement effect, and may have an average diameter of about 1 to 20 nm. The type of quantum dot 12 used in the technology disclosed herein is not particularly limited, and examples thereof include II-VI, III-V, and IV materials. Specifically, the quantum dots 12 are made of ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, GaN, GaP, GaAs, GaSb, InP, InAs, InSb, AlS, AlP, AlAs, AlSb, PbS, PbSe, Ge and Si. It may be one or more selected from the group. The quantum dots 12 may have a single structure or a core-shell structure.

In addition, the quantum dot 100 may be mainly synthesized by a wet process in which a precursor material is placed in an organic solvent and nanoparticles are grown. Depending on the degree of growth of the nanoparticles, light of various wavelengths can be obtained according to the control of the energy bandgap.

The quantum dot 100 described above is also commonly used as a quantum dot (QD), and this quantum dot 100 includes a core part 110, a shell part 120, a ligand part 130 and a polar part 140 do.

Referring to FIG. 2 , the core part 110 is a spherical central body and is located at the center of the quantum dot 100 . The core part 110 is configured to increase high quantum efficiency and structural stability of the quantum dots 100 .

Referring to (a), (b) and 2 of FIG. 1 , the shell part 120 may have a spherical shape surrounding the core part 110 and having a predetermined thickness. In addition, the shell portion 120 helps achieve confinement of charge carriers such as electrons and holes and effective removal of surface states, thereby improving quantum yield and stability.

In addition, the shell part 120 serves to protect from environmental changes and photo-oxidative decomposition.

In addition, the surface of the shell part 120 has a structure in which a ligand part 130, which is a polymer ligand, is attached to facilitate dispersion and control, as shown in (a), (b) and FIG. 1 of FIG. 1 .

The ligand portion 130 is coupled to the shell portion 120, and at least one may be formed as shown in (a), (b) and FIG. 2 of FIG. 1 .

In addition, at least one ligand portion 130 may be a hydrocarbon chain.

Specifically, one side of the ligand portion 130 is connected to a binding group (eg, -SH, -COOH) bonded to the surface of the shell portion 120, and the other side of the ligand portion 130 is -NH ₃ ⁺ , -COO-, -SO ₃ ^- coupled with the polarity portion 140 ^, such as.

The ligand 130 not only physically protects the nanocrystal from the surrounding environment, but also helps prevent the Auger recombination effect by enhancing the photoluminescence quantum yield due to effective passivation of electron traps.

As shown in (a) and (b) of FIG. 1 , the polarity portion 140 is bonded to the ligand portion 130 and has either a positive polarity or a negative polarity.

Specifically, the polarity portion 140 has one polarity of an anode or a cathode by ligand substitution with at least one ligand portion 140 .

As the quantum dots 100 according to an embodiment of the present invention according to the above have either a positive or negative polarity, they can be used to manufacture quantum dots and non-conductive particle patterns through patterning using electrophoresis.

2. Manufacturing method of quantum dots for photoluminescence

Hereinafter, a method of manufacturing a quantum dot for a photoluminescent system according to an embodiment of the present invention will be described with reference to FIGS. 1 to 6 .

In particular, the method of manufacturing a quantum dot for a photoluminescence system according to an embodiment of the present invention shows steps S100 to S200 in the flow chart shown in FIG. 4 .

4 is a flowchart illustrating a method of arranging quantum dots for a photoluminescence system using electrophoresis according to an embodiment of the present invention. 5 is a conceptual diagram illustrating a process of ligand substitution of quantum dots in a method for arranging quantum dots for a photoluminescence system using electrophoresis according to an embodiment of the present invention.

Referring to FIG. 4, the method of manufacturing quantum dots for photoluminescence system according to an embodiment of the present invention is a method of manufacturing quantum dots used to manufacture an electroluminescent device through patterning using electrophoresis, (a) non-polarity Preparing the quantum dots that stand out (S100), (b) surface-modifying the non-polar quantum dots (S200), (c) washing the surface-modified quantum dots (S300), and (d) dispersing the washed quantum dots in water and generating polarized quantum dots 100 (S400), wherein the quantum dots 100 have either a positive polarity or a negative polarity by ligand substitution.

Here, the electroluminescent element is an element applied to a display device for visually outputting, such as a TV or a monitor, and may be illustratively a QLED.

Step (a) is a preparation step for preparing the polar quantum dot 100 shown in FIGS. 1 and 2, and includes (a1) a container containing a dispersion solution and an acid compound or base compound having a mercapto functional group. preparing, (a2) adding non-polar quantum dots to a container and then heating them, and (a3) preparing a dispersion solution, an acid compound or base compound having a mercapto functional group, and non-polar quantum dots according to a predetermined temperature. and reacting for a set period of time.

Next, in the step (b), a method of adding a material having a charge to the dispersion solution of quantum dots and heating may be used to modify the surface of the quantum dots. Materials used to modify the surface of quantum dots include acid or base compounds having mercapto functional groups, specifically mercaptoacetic acid (MAA), 3-mercaptopropionic acid , cysteamine, aminoethanethiol, or N,N-dimethyl-2-mercaptoethyl ammonium may be used alone or in combination. The reaction temperature at the time of surface modification may be carried out for 30 minutes to 10 hours, preferably 1 hour to 10 hours in the temperature range of 25 ~ 200 ℃.

Next, the step (c) is a step of removing residual substances and impurities coexisting with the surface-modified quantum dots, (c1) preparing a washing container containing an organic solvent, (c2) adding the surface-modified quantum dots to the organic solvent. and (c3) drying the washed quantum dots by at least one of natural drying and vacuum drying to remove residual solvent.

That is, when the reaction in step (b) is completed, a washing process is performed in step (c). At this time, the washing process may repeat the process of dispersing and precipitating in an organic solvent. ~10 repetitions are preferred. When the washing is completed as described above, it is preferable to remove the residual solvent among the washed quantum dots by natural drying, vacuum drying, or the like. By removing the residual solvent, the formation of aggregates of quantum dots can be more effectively prevented. In order to sufficiently remove the residual solvent, vacuum drying is preferably performed for 1 to 12 hours.

In this way, when the residual solvent is removed, the quantum dots may be dispersed in a solvent to be used, for example, water or a buffer solution such as Tris buffer to form a quantum dot dispersion solution. Since not only surface-modified quantum dots, but also aggregates and impurities of quantum dots exist in the dispersion solution, they can be removed by methods such as column, filtering, and centrifugation, preferably centrifugation.

Finally, the step (d) is a step in which the quantum dots 100 having the desired polarity are finally completed, (d1) forming a quantum dot dispersion solution in which the residual solvent is removed in a buffer solution, (d2) Removing aggregates and impurities of quantum dots present in the quantum dot dispersion solution by centrifugation, (d3) mixing the pH-adjusted buffer solution with the quantum dot dispersion solution, and (d4) adjusting the pH to charge the surface-modified quantum dots. It includes giving

To this end, a dispersion solution is first prepared. The dispersion of the surface-modified quantum dots may be dispersed in water at a concentration of 1% by weight or more, preferably 3% by weight or more. When a dispersion solution having the above concentration is used, a uniform and dense single layer can be formed.

After dispersing the surface-modified quantum dots as described above in a solvent, the pH of the quantum dot dispersion solution is adjusted by mixing with a pH-adjusted buffer solution. The quantum dot dispersion solvent is not particularly limited as long as it is a solvent capable of adjusting pH, and water or a polar solvent may be used. The pH of the quantum dot dispersion solution may be in the range of 6 to 9, preferably in the range of 7 to 8.

Desired charges may be imparted to the surface of the quantum dots 100 by adjusting the pH according to the material used for surface modification. For example, if the quantum dot 12 capped with oleic acid is used and the surface is modified with cysteamine (CAm) and mercaptopropionic acid (MPA), respectively, and then dispersed in pH 6 and pH 8 water, the other end of the ligand portion 130 As positive charges (-NH3+) and negative charges (-COO-), which are the polarity portions 140, are respectively imparted to the polarities, the quantum dots 100 having a polarity are formed.

6 is fluorescence (= photoluminescence) (PL: Photoluminescence) according to wavelengths related to ligand substitution and zeta potential control by dispersing quantum dots used in the method of arranging quantum dots for a photoluminescence system according to an embodiment of the present invention. ) is a graph showing the intensity.

In the ligand substitution technology for water-dispersed quantum dots, polar ligand substitution technology may be applied to form a thin film using electrophoresis and improve uniformity.

Adjust the pH and zeta potential of the quantum dot dispersion solution to improve fairness (>± 70mV@pH 6-8) and improve the stability of water-dispersed quantum dots according to the QD-ligand anchor group (single and multi-anchor ligands).

In addition, RGB quantum dot materials of II-VI and III-V compositions are synthesized to realize a QD structure for ultra-high luminance. Specifically, excition dynamics are controlled by adjusting shell thickness and core/shell junction barriers, and formation of surface traps is suppressed by optimizing conditions by introducing a ligand anchor group.

On the other hand, quantum dots may be polarized by being dispersed by zeta potential in addition to the ligand substitution described above.

3. Quantum dot array device for photoluminescence (300)

Hereinafter, an apparatus for arranging quantum dots for a photoluminescence system used in a method for arranging quantum dots for a photoluminescence system using electrophoresis according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3 .

3 is a conceptual diagram showing a quantum dot arrangement device for a photoluminescence system used in a method for arranging quantum dots for a photoluminescence system using electrophoresis according to an embodiment of the present invention.

Referring to FIG. 3 , the quantum dot array device 300 for a photoluminescence system includes a receiving part 310 , an electrode part 320 , a power connection part 330 and a power supply part 340 .

The accommodating part 310 is a container for accommodating the polar solvent S, the polar quantum dots 100, the non-conductive particles 200, and the electrode part 320, and as shown in FIG. 3, it may be a cylindrical shape with an open top. can

The electrode unit 320 includes a positive electrode substrate 321 and a negative electrode substrate 322 .

The positive electrode substrate 321 is a substrate positioned inside the accommodating part 310 and is immersed in the polar solvent S as shown in FIG. 3 . A predetermined pattern is formed on the positive electrode substrate 321 in which the quantum dots 100 and the non-conductive particles 200 having a polarity to be realized are patterned.

In addition, since the positive electrode substrate 321 is electrically connected to the power supply unit 340 by the power connection unit 330, when the power supply unit 340 operates, power is applied and the positive electrode (+) is applied.

The negative electrode substrate 322 is a substrate positioned inside the accommodating part 310 so as to face the positive electrode substrate 321 and is immersed in the polar solvent S as shown in FIG. 3 . A predetermined pattern is formed on the negative electrode substrate 322 in which the quantum dots 100 and non-conductive particles 200 having a polarity to be realized are patterned.

In addition, since the negative electrode substrate 322 is electrically connected to the power supply unit 340 through the power connection unit 330, when the power supply unit 340 operates, power is applied and a negative electrode (-) is applied.

The power connection unit 330 includes a positive connection line 331 and a negative connection line 332 .

The positive electrode connection line 331 is an electric wire electrically connecting the positive electrode substrate 321 and the power supply unit 340 .

The negative electrode connection line 332 is an electric wire electrically connecting the negative electrode substrate 322 and the power supply unit 340 .

The power supply unit 340 applies power to the positive electrode substrate 321 and the negative electrode substrate 322 so that the positive electrode substrate 321 has a positive polarity and the negative electrode substrate 322 has a negative polarity.

At this time, the voltage applied from the power supply unit 340 is a relatively low voltage of 1V to 30V.

4. Arrangement method of quantum dots for photoluminescence using electrophoresis

Hereinafter, a method of arranging quantum dots for a photoluminescence system using an electrophoresis method according to an embodiment of the present invention will be described with reference to FIGS. 1 to 10 .

It is specified that the method for arranging quantum dots for a photoluminescence system according to an embodiment of the present invention is a method for arranging quantum dots for a photoluminescence system other than quantum dots for an electroluminescence system.

Referring to FIG. 4, the method of arranging quantum dots for a photoluminescence system using electrophoresis according to an embodiment of the present invention is a method of arranging quantum dots for a photoluminescence system used to manufacture an electroluminescent device through patterning using an electrophoresis method. (a) preparing non-polar quantum dots and non-polar insulator particles (S100), (b) combining non-polar quantum dots and non-polar insulator particles into polar quantum dots 100 and polar insulator particles (200) step of converting (S200), (c) mixing and dispersing the polar quantum dots (100) and polar non-conductor particles (200) in a polar solvent (S) (S300) and (d) electricity A step (S400) of patterning the polar quantum dots 100 and the polar non-conductive particles 200 using the electrophoresis method.

At this time, the plurality of polarized quantum dots 100 are positioned to be spaced apart from each other by the plurality of non-conductive particles 200 as shown in FIG. 3 .

Here, the electroluminescent element is an element applied to a display device for visually outputting, such as a TV or a monitor, and may be illustratively a QLED.

The step (a) is a preparation step for preparing the polar non-conductor particles shown in FIGS. 1 and 2 and the non-conductive particles shown in FIG. preparing a receiving container containing the prepared acid compound or base compound, (a2) adding non-polar quantum dots and non-polar non-conductor particles to the receiving container and then heating it; and (a3) adding the dispersion solution and the mercapto functional and reacting the provided acid compound or base compound, non-polar quantum dots, and non-polar non-conductor particles at a predetermined temperature for a predetermined time.

Next, the step (b) includes (b1) surface-reforming the non-polar quantum dots and non-polar non-conductor particles, (b2) washing the surface-modified quantum dots and non-conductor particles, and (b3) washing the quantum dots and and dispersing non-conductive particles in water to produce polar quantum dots and polar non-conductive particles.

In the step (b), a method of adding a material having a charge to the dispersion solution of the quantum dots and heating the surface of the quantum dots shown in FIGS. 3 and 4 may be used. Materials used to modify the surface of quantum dots include acid or base compounds having mercapto functional groups, specifically mercaptoacetic acid (MAA), 3-mercaptopropionic acid , cysteamine, aminoethanethiol, or N,N-dimethyl-2-mercaptoethyl ammonium may be used alone or in combination. The reaction temperature at the time of surface modification may be carried out for 30 minutes to 10 hours, preferably 1 hour to 10 hours in the temperature range of 25 ~ 200 ℃.

Specifically, the step (b2) includes preparing a washing container containing an organic solvent, dispersing and precipitating the surface-modified quantum dots and non-conductive particles in the organic solvent, and washing the washed quantum dots and and drying the non-conductive particles by at least one of natural drying and vacuum drying to remove residual solvent.

That is, when the reaction is completed in step (b1), a washing process is performed in step (b2). At this time, the washing process may repeat the process of dispersing and precipitating in an organic solvent. ~10 repetitions are preferred. When the washing is completed as described above, it is preferable to remove the residual solvent among the washed quantum dots by natural drying, vacuum drying, or the like. By removing the residual solvent, the formation of aggregates of quantum dots can be more effectively prevented. In order to sufficiently remove the residual solvent, vacuum drying is preferably performed for 1 to 12 hours.

In this way, when the residual solvent is removed, the quantum dots may be dispersed in a solvent to be used, for example, water or a buffer solution such as Tris buffer to form a quantum dot dispersion solution. Since not only surface-modified quantum dots, but also aggregates and impurities of quantum dots exist in the dispersion solution, they can be removed by methods such as column, filtering, and centrifugation, preferably centrifugation.

Next, the step (b3) is a step in which the quantum dots 100 having the desired polarity are finally completed, and a step of forming a quantum dot dispersion solution in which the residual solvent is removed and the non-conductive particles are dispersed in a buffer solution, by centrifugation. Removing agglomerates and impurities of quantum dots and non-conducting particles from the quantum dot and non-conducting particle dispersion solution, mixing the pH-adjusted buffer solution with the quantum dot and non-conducting particle dispersion solution, and surface-modified quantum dot and non-conducting particles by adjusting the pH Including the step of imparting an electric charge to.

To this end, a dispersion solution is first prepared. The dispersion of the surface-modified quantum dots may be dispersed in water at a concentration of 1% by weight or more, preferably 3% by weight or more. When a dispersion solution having the above concentration is used, a uniform and dense single layer can be formed.

After dispersing the surface-modified quantum dots as described above in a solvent, the pH of the quantum dot dispersion solution is adjusted by mixing with a pH-adjusted buffer solution. The quantum dot dispersion solvent is not particularly limited as long as it is a solvent capable of adjusting pH, and water or a polar solvent may be used. The pH of the quantum dot dispersion solution may be in the range of 6 to 9, preferably in the range of 7 to 8.

Desired charges may be imparted to the surface of the quantum dots 100 by adjusting the pH according to the material used for surface modification. For example, if the quantum dot 12 capped with oleic acid is used and the surface is modified with cysteamine (CAm) and mercaptopropionic acid (MPA), respectively, and then dispersed in pH 6 and pH 8 water, the other end of the ligand portion 130 As positive charges (-NH3+) and negative charges (-COO-), which are the polarity portions 140, are respectively imparted to the polarities, the quantum dots 100 having a polarity are formed.

In the ligand substitution technology for water-dispersed quantum dots, polar ligand substitution technology may be applied to form a thin film using electrophoresis and improve uniformity.

Adjust the pH and zeta potential of the quantum dot dispersion solution to improve fairness (>± 70mV@pH 6-8) and improve the stability of water-dispersed quantum dots according to the QD-ligand anchor group (single and multi-anchor ligands).

In addition, RGB quantum dot materials of II-VI and III-V compositions are synthesized to realize a QD structure for ultra-high luminance. Specifically, excition dynamics are controlled by adjusting shell thickness and core/shell junction barriers, and formation of surface traps is suppressed by optimizing conditions by introducing a ligand anchor group.

Next, in the step (c), as shown in FIG. 3, the polar quantum dots 100 and the polar non-conductor particles 200 are mixed and dispersed in the polar solvent S.

Referring to FIG. 3 , polar non-conductive particles 200 are formed to be relatively larger than polar quantum dots 100 .

In addition, the polar solvent (S) is a material capable of forming an electric field, and includes water, deionized water (DIW), acetone, ether, chloroform, ethyl acetate, isopropyl alcohol (IPA: Iso Propyl Alcohol), hexane, benzene, and toluene. includes at least one of

In particular, as the polarized quantum dots 100 and the polarized non-conductor particles 200 are dispersed by zeta potential, they have either positive or negative polarity.

As another method, the polarized quantum dots 100 and polarized non-conductor particles 200 become either positive or negative polarity as they are dispersed by ligand substitution.

In addition, the polar non-conductive particles 200 may include at least one of polymer particles and ceramic particles.

Next, in the step (d), (d1) the polar solvent (S) accommodated in the accommodating part (310), the polarized quantum dots (100) dispersed in the polar solvent (S), and the polar non-conductor particles (200) (d2) immersing the positive electrode substrate 321 and the negative electrode substrate 322 on which a predetermined pattern is formed in a polar solvent (S), and (d3) the power supply unit 340 is connected to the positive electrode substrate 321 and It is electrically connected to the negative electrode substrate 322 and applies power to the positive electrode substrate 321 and the negative electrode substrate 322 to form an electric field in a predetermined pattern.

At this time, the form of the electric field includes direct current (DC) and alternating current (AC).

7 is a conceptual diagram illustrating a process of simulating and patterning polarized quantum dots and non-conductive particles in a method for arranging quantum dots for a photoluminescence system using electrophoresis according to an embodiment of the present invention.

First, the step (f) may further include a step (S605) of FEM simulating the polarized quantum dots 100 before the step (f1), as shown in the leftmost drawing of FIG. 7 .

Next, as shown in the center of FIGS. 3 and 7 , the polar solvent accommodated in the accommodating part 310, the polarized quantum dots 100 dispersed in the polar solvent, and the non-conductive particles 200 are prepared.

At this time, the polar solvent may include at least one of water, deionized water (DIW), acetone, ether, chloroform, ethyl acetate, isopropyl alcohol (IPA: Iso Propyl Alcohol), hexane, benzene, toluene, In addition to the polar solvents described above, any solvent that can act as a polar solvent may be applied.

In addition, the quantum dots 100 having the above polarity may be in a dispersed state due to zeta potential or may be in a dispersed state due to ligand substitution.

In addition, the polarized quantum dots 100 may have at least one of positive and negative charges in a polar solvent.

In the step (d3), the potential difference and current between the two electrodes from the power supply unit is applied to the positive electrode substrate and the negative electrode substrate by using direct current (DC) or alternating current (AC) alone or by using both direct current (DC) and alternating current (AC) together.

In addition, in the step (d), after the step (d3), (d4) the polarized quantum dots 100 and polar non-conductor particles 200 dispersed in the polar solvent (S) form the surface of the positive electrode substrate 321. A step of being arranged in at least one of a predetermined pattern and a predetermined pattern of the negative electrode substrate 322 and patterning by electrophoresis, and (d5) taking out the positive electrode substrate 321 and the negative electrode substrate 322 from the polar solvent (S) A drying step (S650) is included.

In the step (d4), the polarized quantum dots 100 and the subconductor 200 are formed by the electric field formed as electricity is applied in the drawings in the center of FIGS. 3 and 7, and the predetermined pattern of the positive electrode substrate and the negative electrode It moves to a predetermined pattern of the substrate.

Specifically, in the predetermined pattern of the positive electrode substrate 321, the quantum dots 100 and non-conductive particles 200 having negative polarity move, and in the predetermined pattern of the negative electrode substrate 322, the quantum dots 100 and The non-conductive particles 200 move.

Accordingly, the polarized quantum dots 100 and non-conductive particles 200 are positioned to be spaced apart as shown on the right side of FIG. 3 in step (f1), and as shown on the lower left side of FIG. 3 in step (f4). It is patterned in a predetermined pattern in a state in which the spaced apart distance is narrowed.

Additionally, the non-conductive particles 200 include at least one of polymer particles (eg, PS particles) and ceramic particles (colloidal silica such as silicon dioxide (SiO 2 )).

In addition, the predetermined patterns of the positive electrode substrate 321 and the negative electrode substrate 322 can be set as desired by the user.

Thereafter, in the step (d5), the positive electrode substrate and the negative electrode substrate on which the quantum dots 100 having polarity are seated in a predetermined pattern are taken out of the polar solvent and dried, thereby forming quantum dots and non-conductor particle patterns for light-emitting systems.

In addition, after the step (d5), a full-color quantum dot pattern may be implemented through a monochromic and full-color patterning process.

In addition, a multi-layered electroluminescent device can be manufactured using the full-color quantum dots and non-conductor particle patterns described above, and a full-color display device having high resolution and high definition, such as a QLED to which the electroluminescent device is applied, can be implemented.

Next, after the step (d5), the present invention includes a step (S700) of inspecting and implementing a quantum dot pattern (e).

8 is a process of realizing the final quantum dot and non-conductive particle pattern by characterizing, analyzing, and device engineering the quantum dot and non-conductive particle patterns arranged by the method of arranging quantum dots for photoluminescence using electrophoresis according to an embodiment of the present invention. It is a conceptual diagram showing

Referring to FIG. 8 , step (e) includes identifying and analyzing the characteristics of the quantum dot and non-conducting particle patterns (S710), device engineering the quantum dot and non-conducting particle patterns (S720), and implementing the quantum dot and non-conducting particle patterns. It includes a step (S730) of doing.

9 is a view of actually measuring quantum dots and non-conductive particle patterns arranged by the method of arranging quantum dots for a photoluminescence system using electrophoresis according to an embodiment of the present invention.

Figure 9 shows a quantum dot and non-conductive particle pattern patterned at 4x12 μm (3378 ppi).

That is, according to the present invention, it is possible to form pixels of 1200 ppi or more (based on sub pixels), and furthermore, as shown in FIG. 9 , it is possible to implement pixels of 3000 ppi or more.

In addition, according to the present invention, quantum dot patterns having different sizes may be implemented as the user sets predetermined patterns of the positive electrode substrate and the negative electrode substrate as desired.

10 is a graph comparing the technical difficulty of quantum dots and non-conductive particle patterns arranged by the method of arranging quantum dots for a photoluminescence system using electrophoresis according to an embodiment of the present invention using electrophoresis with those of the prior art.

Figure 10 shows a prior art process for nanometer level pixel implementation and the process of the present invention.

Processes based on process technologies other than conventional inkjet printing fall far short of the commercialization level, and even in the case of the most advanced inkjet printing, development is slow due to difficult processes, and it is difficult to implement nanometer-level pixels close to the semiconductor process limit.

However, with the processor according to the present invention, it is possible to implement a pixel at a level close to the general semiconductor process limit without changing the technical difficulty even when the resolution is increased.

That is, the present invention does not have the weakness of a rapid increase in technical difficulty as the resolution increases, which is a limitation of conventional inkjet technology, and there is almost no change in technical difficulty according to high resolution as shown in the graph below, so that the ultra-fine semiconductor process has It is also possible to respond to the patterning process.

In addition, at least one of an electroluminescent device and a QD panel may be manufactured by applying the method of arranging quantum dots for a photoluminescent system using electrophoresis according to the present invention.

According to the above, the present invention is a technology capable of arranging quantum dots and non-conductive particles dispersed in a solvent at a low voltage of about 1V to 30V at a desired position and size, and a pixel of 1200 ppi or higher (sub pixel basis) that cannot be formed in the prior art can be formed, and furthermore, 3000 ppi or more can be realized.

In addition, the present invention can be implemented with a thickness greater than that of the photoluminescent quantum dot pixel.

In addition, the present invention can implement an ultra-high resolution electroluminescent device by preventing a quenching phenomenon (a phenomenon in which light is reduced) that frequently occurs between quantum dots according to the prior art.

In addition, the present invention is a process applicable to flexible displays, glass-based displays, and silicon wafer-based displays, and when water is used among polar solvents, it reduces the burden of environmental pollution and harmful working environments. concerns can be alleviated.

In addition, in the present invention, when the quantum dots have a certain distance due to the insulator particles and the thickness of the arrayed quantum dots and the insulator becomes thick, it can be used as a photoluminescent quantum dot.

The above description of the present invention is for illustrative purposes, and those skilled in the art can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts should be interpreted as being included in the scope of the present invention.

100: polarized quantum dots
110: core part
120: shell part
130: ligand part
140: polarity
200: polar non-conductive particles
300: Quantum dot array device for photoluminescence
310: receiving part
320: electrode part
321: positive electrode substrate
322: negative electrode substrate
330: power connection
331: positive connection line
332: negative connection line
340: power supply

Claims (14)

In the method of arranging quantum dots for photoluminescence,
(a) preparing non-polar quantum dots and non-polar non-conductor particles;
(b) converting the non-polar quantum dots and non-polar insulator particles into polar quantum dots and polar insulator particles;
(c) mixing and dispersing the polarized quantum dots and the non-conductive particles having polarity in a polar solvent; and
(d) patterning the polar quantum dots and the non-conductive particles having polarity using electrophoresis;
A method of arranging quantum dots for a photoluminescent system using electrophoresis, characterized in that the plurality of polarized quantum dots are positioned to be spaced apart from each other by the polar non-conductive particles formed in plurality.
According to claim 1,
The method of arranging quantum dots for a photoluminescence system using electrophoresis, characterized in that the non-conductive particles having a polarity are relatively larger than the quantum dots having a polarity.
According to claim 1,
In step (a),
(a1) preparing a container containing a dispersion solution and an acid compound or base compound having a mercapto functional group;
(a2) injecting the non-polar quantum dots and the non-polar non-conductor particles into the container and then heating them; and
(a3) reacting the dispersion solution, the acid compound or base compound having the mercapto functional group, the non-polar quantum dots, and the non-polar non-conductor particles at a predetermined temperature for a predetermined time; Quantum dot arrangement method for photoluminescence using electrophoresis, characterized in that it comprises a.
According to claim 1,
In step (b),
(b1) surface-modifying the non-polar quantum dots and the non-polar non-conductor particles;
(b2) washing the surface-modified quantum dots and non-conductive particles; and
(b3) water-dispersing the washed quantum dots and non-conductive particles to generate polar quantum dots and non-conductive particles;
According to claim 4,
In step (b2),
preparing a washing container containing an organic solvent;
washing by alternately dispersing and precipitating the surface-modified quantum dots and non-conductive particles in the organic solvent; and
A method of arranging quantum dots for a photoluminescent system using electrophoresis, characterized in that it comprises: drying the washed quantum dots and non-conductive particles by at least one of natural drying and vacuum drying to remove residual solvent.
According to claim 5,
In step (b3),
Forming a quantum dot dispersion solution in which the residual solvent is removed and the quantum dot and non-conductive particles are dispersed in a buffer solution;
removing agglomerates and impurities of quantum dots and non-conducting particles present in the dispersion solution of quantum dots and non-conducting particles by centrifugation;
mixing a pH-adjusted buffer solution with the dispersion solution of quantum dots and non-conductive particles; and
A method of arranging quantum dots for a photoluminescent system using electrophoresis, comprising: adjusting the pH to impart charge to the surface-modified quantum dots and non-conductive particles.
According to claim 1,
In step (d),
(d1) preparing the polar solvent accommodated in the accommodating unit, the polar quantum dots dispersed in the polar solvent, and the non-conductor particles having polarity;
(d2) immersing the positive electrode substrate and the negative electrode substrate on which a predetermined pattern is formed into the polar solvent; and
(d3) forming an electric field in the predetermined pattern by a power supply unit electrically connected to the positive electrode substrate and the negative electrode substrate and applying power to the positive electrode substrate and the negative electrode substrate;
The method of arranging quantum dots for photoluminescence using electrophoresis, characterized in that the form of the electric field includes direct current (DC) and alternating current (AC).
According to claim 7,
In step (d),
(d4) quantum dots having polarity and nonconductor particles having polarity dispersed in the polar solvent are arranged in at least one of a predetermined pattern of the positive electrode substrate and a predetermined pattern of the negative electrode substrate and patterned by the electrophoresis method step; and
(d5) taking out the positive electrode substrate and the negative electrode substrate from the polar solvent and drying them;
According to claim 7,
The polar solvent is a material capable of forming the electric field and is at least one of water, deionized water (DIW), acetone, ether, chloroform, ethyl acetate, isopropyl alcohol (IPA), hexane, benzene, and toluene. A method of arranging quantum dots for photoluminescence using electrophoresis, characterized in that it comprises one.
According to claim 1,
The polarized quantum dots and the polarized non-conductor particles are dispersed by zeta potential, so that they exhibit either positive or negative polarity.
According to claim 1,
A method of arranging quantum dots for a photoluminescence system using electrophoresis, characterized in that the polarized quantum dots and the non-conductor particles having polarity exhibit either positive or negative polarity as they are dispersed by ligand substitution.
According to claim 1,
The method of arranging quantum dots for a photoluminescent system using electrophoresis, characterized in that the polar non-conductive particles include at least one of polymer particles and ceramic particles.
An electroluminescent device manufactured by applying the method of arranging quantum dots for a photoluminescence system using electrophoresis according to claim 1.
A QD panel for a display manufactured by applying the method of arranging quantum dots for photoluminescence using electrophoresis according to claim 1.

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