KR101413660B1 - Quantum dot-polymer composite plate for light emitting diode and method for producing the same - Google Patents

Abstract

Disclosed is a quantum dot-polymer composite plate for a light emitting diode and a manufacturing method thereof. The quantum dot-polymer composite plate according to the present invention includes a polymer thin film including quantum dots that convert wavelength of excitation light of a light emitting diode to generate wavelength conversion light; And an inorganic oxide protective film formed on at least one surface of the polymer thin film. According to the present invention, aggregation, oxidation and deterioration of the quantum dots can be prevented, and the luminous efficiency is improved.

Description

[0001] The present invention relates to a quantum dot-polymer composite plate for a light emitting diode and a method of manufacturing the same.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to quantum dots (QDs) for light-emitting diodes for generating wavelength-converted light by wavelength-converting excitation light of a light emitting diode, A manufacturing method thereof, and a light emitting device using such a quantum dot and a manufacturing method thereof.

Quantum dots are nanoparticles having a size of several tens of nanometers (nm) or less, which have semiconductor characteristics, and are a key material attracting attention because they exhibit characteristics different from those of bulk size due to a quantum confinement effect. Such a quantum dot absorbs light from an excitation source and reaches an energy-excited state, thereby emitting energy corresponding to an energy band gap of a quantum dot. Therefore, by controlling the size or the material composition of the quantum dots, the bandgap can be controlled, and energy of various levels of wavelength band can be utilized. In general, quantum dots exhibit a phenomenon in which the bandgap increases as the size of the particles decreases. As a result, as the particle size decreases, the emission wavelength shifts blue-shifted. In addition, when the particle size is extremely reduced, the proportion of the atoms or ions existing on the surface of the material increases. As a result, due to the extremely small size of the particles such as the lowering of the melting point or the decrease of the crystal lattice constant, It exhibits new optical, electrical and physical properties that could not be seen. Accordingly, researches for application to a display, a light emitting diode (LED), a bio-field, and the like using quantum dots having the above characteristics are actively under way.

Demand for white LEDs is high in the LED field. In the method of manufacturing a white LED, there is a method of combining white LEDs with LED chips of various colors, or combining LED chips emitting light of a specific color and phosphors emitting fluorescence of a specific color. In the currently commercialized white LED, the latter method is applied to obtain a white LED package by encapsulating a blue LED chip with a molding resin in which a yellow phosphor is dispersed.

To replace previously used bulk fluorescent materials in the field of LEDs, for example, US Pat. No. 6,501,091 discloses an LED in which quantum dots are dispersed in a host matrix. In order to use quantum dots for LED wavelength conversion, it is necessary to mix a paste resin and a quantum dot such as a silicone resin or an epoxy resin, which is used as a paste of a conventional bulk fluorescent material, . However, when the paste resin and the quantum dot are mixed, there is a problem that the affinity between the quantum dot and the resin is poor and the quantum dots are not well dispersed in the resin and aggregated to decrease the efficiency of the wavelength conversion light through the quantum dot.

In addition, the quantum dot-based LED package manufactured using a silicone resin and an epoxy resin has a phenomenon in which a degradation phenomenon at a curing temperature of 150 ° C, which is a silicone resin, is inevitable, resulting in a decrease in luminescence characteristics and quantum efficiency. When a quantum dot having a hydrophobic surface property is mixed in a silicone resin, redeposition phenomenon occurs due to the reabsorption phenomenon between the particles due to the aggregation phenomenon of the quantum dots. In addition, oxidation of the surface of the quantum dots occurs due to permeation of oxygen and moisture in the atmosphere due to the low water vapor transmission rate (WVTR) of the silicone resin, and is included in the molding resin due to the heat generated in the LED chip itself And the phenomenon that the quantum dots are deteriorated and the LED characteristics are changed according to the driving time.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for preventing the agglomeration, oxidation and deterioration of quantum dots generating wavelength converted light by wavelength conversion of excitation light of an LED.

A problem to be solved by the present invention is to provide a light emitting device in which the light emitting efficiency of wavelength converted light is improved by using such a quantum dot and a method of manufacturing the same.

In order to solve the above problems, the present invention proposes a quantum dot-polymer composite plate. If the conventional QD method is a QD near LED encapsulation method, the QD-polymer composite plate of the present invention is a remote type LED encapsulation system in which quantum dots and LED are separated from each other, and the QD- Oxidation and deterioration of the quantum dots can be prevented, thereby realizing a long-life quantum dot-based light emitting device.

The quantum dot-polymer composite plate according to the present invention includes a polymer thin film including quantum dots that convert wavelength of excitation light of a light emitting diode to generate wavelength conversion light; And an inorganic oxide protective film formed on at least one surface of the polymer thin film.

The inorganic oxide protective film may be a thin film of a material selected from the group consisting of SiO ₂ , TiO ₂ , Al ₂ O _3, and mixtures thereof or glass. A polymer adhesive layer may be further disposed between the polymer thin film and the inorganic oxide protective film. The polymeric adhesive layer may be polyvinylpyrrolidone (PVP) or polyvinyl alcohol (PVA).

In the method for preparing a quantum dot-polymer composite plate according to the present invention, a polymer solution is prepared by dissolving a polymer in an organic solvent. Quantum dots that convert wavelength of excitation light of the light emitting diode and generate wavelength conversion light are mixed into the polymer solution. The polymer solution mixed with the quantum dots is dried to form a polymer thin film containing quantum dots, and then an inorganic oxide protective film is formed on at least one side of the polymer thin film.

In this case, the step of forming the polymer adhesive layer may further include forming a polymer adhesive layer between the polymer thin film and the inorganic oxide protective film. In the step of forming the polymer adhesive layer, the polymer thin film is dipped in an ethanol solution in which PVP or PVA is dissolved Dip coating and drying.

The step of forming the inorganic oxide protective film may be performed by dip coating the polymer thin film in a silica sol solution and drying the polymer thin film.

The quantum dot-polymer composite plate according to the present invention is applied to a light emitting diode composed of a semiconductor laminate, and is realized as an LED package. The quantum dot-polymer composite plate can be bonded to the light emitting diode using an adhesive such as? -Cyanoacrylic acid ester.

According to the present invention, it is possible to prevent the aggregation phenomenon of quantum dots frequently occurring in the process of manufacturing quantum dot-based LEDs manufactured using silicone resins and epoxy resins that have been used. In the present invention, in order to prevent the aggregation phenomenon of quantum dots formed when a quantum dot having a hydrophobic surface is mixed with a silicone resin or an epoxy resin, a quantum dot is more uniformly dispersed by using a polymer in an organic solvent, thereby minimizing light scattering To maintain the high transmittance of the quantum dot-polymer composite plate.

An inorganic oxide protective film may be formed on the surface of the polymer thin film including the quantum dots to prevent surface oxidation and ligand detachment of the quantum dots by moisture and oxygen in the atmosphere. In addition, the manufacture of a quantum dot-polymer composite plate, which is a remote type in which quantum dots and LEDs are separated from each other, can reduce quantum dot deterioration due to heat generation of the LED chip itself. Accordingly, even when driving for a long time, the characteristics of the LED are not changed so that the stability of the device according to the driving time of the quantum dot-based white LED can be improved.

In addition, such a quantum dot-polymer composite plate is advantageous for thinning a light emitting device and can be combined with an LED by a simple process. Therefore, it is easier to manufacture a light emitting device capable of emitting light of a desired color and a white light emitting device of high color rendering It becomes.

1 is a cross-sectional view of a quantum dot-polymer composite plate according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating a method of fabricating a quantum dot-polymer composite plate according to an embodiment of the present invention.
3 is a cross-sectional view of a quantum dot-polymer composite plate according to another embodiment of the present invention.
FIG. 4 is a transmittance spectrum according to the quantum dot concentration of the CuInS ₂ / ZnS quantum dot-polymer composite plate according to the present invention.
FIG. 5 shows EL (electroluminescence) spectra according to the quantum dot concentration in a white LED based on a CuInS ₂ / ZnS quantum dot-polymer composite plate according to the present invention.
FIG. 6 shows the color rendering index, the correlated color temperature, the CIE color coordinates, and the CIE color coordinates of a white LED based on a quantum dot-polymer composite plate using 1.5 ml CuInS ₂ / ZnS quantum dots at 20 mA This is a photograph of a white LED during driving.
FIG. 7 is a graph of the EL emission intensity according to the driving time of the white LED using the CuInS ₂ / ZnS quantum dot-polymer thin film without the inorganic oxide thin film and the white LED manufactured by mixing the quantum dot and the silicone resin according to the conventional method .
8 is an optical microscope photograph of the polymer thin film containing CuInS ₂ / ZnS quantum dots before and after the surface treatment.
FIG. 9 is a graph showing EL light emission intensity measured with a driving time of 20 mA by applying a quantum dot-polymer composite plate having different kinds of inorganic oxide protective films to an LED.
10 is a photograph of a sample prepared according to the change of the quantum dot concentration of a quantum dot-polymer composite plate using a CuInS ₂ / ZnS quantum dot and a ZnCdSe / ZnS quantum dot.

Hereinafter, a preferred embodiment of a quantum dot-polymer composite plate and a manufacturing method thereof according to the present invention will be described in detail with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. It is provided to let you know.

FIG. 1 is a cross-sectional view of a quantum dot-polymer composite plate according to an embodiment of the present invention, and FIG. 2 is a flowchart showing a manufacturing method thereof.

1, a quantum dot-polymer composite plate 100 according to an embodiment of the present invention includes a polymer thin film 10 including a quantum dot 5 and a structure in which an inorganic oxide protective film 30 is formed on a top surface and a bottom surface of the polymer thin film 10 . The polymeric adhesive layer 20 is included between the polymer thin film 10 and the inorganic oxide protective film 30.

The quantum dot-polymer composite plate 100 is bonded to a light emitting diode composed of a semiconductor laminate and used as an encapsulating material. At this time, the quantum dots 5 are for producing wavelength-converted light by wavelength-converting the excitation light of the light emitting diode. The quantum dots 5 are manufactured by a vapor deposition method such as MOCVD or a chemical wet synthesis method in which a precursor material is put into an organic solvent to grow crystals GaN, GaP, GaAs, AlN, AlP, AlAs, InN, and InP, such as CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, and HgTe. , III-V compound semiconductor nanocrystals such as InAs, or a mixture thereof.

The polymer adhesive layer 20 may be PVP or PVA and serves to uniformly form the inorganic oxide protective film 30 on the surface of the polymer thin film 10. The inorganic oxide protective film 30 is formed to prevent the quantum dots 5 from being in contact with oxygen or moisture. The inorganic oxide protective film 30 is preferably formed by a simple solution coating process, and SiO ₂ , TiO ₂ , Al ₂ O _3, A thin film of a material selected from the group consisting of Since the inorganic oxide protective film 30 has a gas permeability lower than that of an organic material, it is possible to prevent shortening of the life time of the quantum dots and is very advantageous in terms of device stability.

The manufacturing method of such a quantum dot-polymer composite plate 100 will be described with reference to FIG.

First, the polymer is dissolved in an organic solvent and prepared (step s1). The polymer serves as a matrix for uniformly dispersing and fixing quantum dots (5 in FIG. 1), and can be a polymer that can be dissolved in an organic solvent such as chloroform or toluene while being transparent to visible light. For example, polyurethane (PU), polyether urethane, polyurethane copolymer, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, polymethyl acrylate (PMA), polymethylmethacrylate (PMMA) (PEMA), polyacrylic acid copolymer (PVAc), polyvinyl acetate copolymer, polypyryl alcohol (PPFA), polylauryl methacrylate (PLMA), polystyrene (PS), polystyrene copolymer, polyethylene oxide , Polypropylene oxide (PPO), polyethylene oxide copolymer, polypropylene oxide copolymer, polycarbonate (PC), polyvinyl chloride (PVC), polycaprolactone (PCL), polyvinylcarbazole Fluoride (PVdF), polyvinylidene fluoride copolymer, and polyamide. There must be water. The organic solvent may be any one selected from the group consisting of chloroform, toluene, octane, heptane, hexane, pentane, trichlorethylene, dimethylformamide (DMF) and tetrahydrofuran (THF). The dissolution can be carried out by an agitation method using a magnetic bar, for example, for 24 hours.

Next, a certain amount of quantum dots are mixed with the polymer solution obtained in step s1 (step s2). After mixing, it can be dispersed through sonication. The sizes and types of quantum dots may be single, but various kinds of materials may be mixed so as to have band gaps of various conversion wavelength ranges such as red, green, and yellow so as to obtain light of a desired color.

The solution prepared in the step s2 is dried for 12 hours, for example, in a vacuum state, and dried in the air for another 12 hours (step s3), and the organic solvent is removed to obtain a polymer thin film containing quantum dots . For example, if the solution prepared in step s2 is dried in an aluminum plate, it can be easily separated from the aluminum plate and a free-standing polymer thin film can be obtained. Alternatively, the solution prepared in step s2 may be formed on a substrate such as a glass substrate by a method such as spin coating and dried to obtain a polymer thin film.

The polymer thin film 10 shown in FIG. 1 has a single layer shape. The polymer thin film 10 having different types of quantum dots can be formed in various layers so as to emit a desired wavelength in consideration of a combination with specific wavelength light emitted by the light emitting diode And then stacking them.

Next, a polymer adhesive layer (20 in Fig. 1) is formed on the polymer thin film (Step s4). When the free-standing polymer thin film obtained in step s3 is dip-coated on the PVP or PVA-dissolved ethanol solution and dried, for example, at 60 DEG C for 1 hour, a polymer adhesive layer 20 is formed on both surfaces of the polymer thin film 10 can do. The polymeric adhesive layer 20 serves as a buffer to uniformly coat the inorganic oxide protective film formed thereafter. The thickness of the polymer adhesive layer 20 can be controlled by controlling the number of coatings.

Next, an inorganic oxide protective film (30 in Fig. 1) is formed (step s5). When the inorganic oxide protective film is a SiO ₂ thin film, the polymer thin film may be dip-coated on the silica sol solution and dried at 60 ° C for 1 hour, for example. The thickness of the inorganic oxide protective film 30 can be controlled by controlling the number of coatings.

After that, it is possible to easily apply a process of bonding a quantum dot-polymer composite plate with a desired size to the LED with an adhesive (σ-cyanoacrylate ester) on an individual LED to easily encapsulate it. Of course, it is also possible to apply a quantum dot-polymer composite plate on a wafer-level semiconductor laminate, and then cut the semiconductor laminate and the quantum dot-polymer composite plate together to form individual elements. The semiconductor laminate may emit ultraviolet light, red light, green light or blue light, and may be applied as a white LED or a RGB light emitting diode by performing various wavelength conversion depending on the size and material type of the quantum dots.

3 is a cross-sectional view of a quantum dot-polymer composite plate according to another embodiment of the present invention. The quantum dot-polymer composite plate 100 'shown in FIG. 3 has a structure in which the polymer thin film 10 including the quantum dots 5 includes a glass substrate 30' as an inorganic oxide protective film on the upper surface and a lower surface.

The method for producing the quantum dot-polymer composite plate 100 'is the same as the previous embodiment until the step of forming the polymer thin film from steps s1 to s3 described with reference to FIG. 2, Sandwiching the substrate 30 'is different. Of course, the solution prepared in step s2 may be formed on one glass substrate 30 'by spin coating or the like, followed by drying to obtain the polymer thin film 10, and then another glass substrate 30' Can also be produced.

In the above embodiments, the inorganic oxide protective film is formed on both the upper and lower surfaces of the polymer thin film including the quantum dots. However, the inorganic oxide protective film may be formed on at least one surface of the polymer thin film, (That is, a surface that meets with the outside air). In the case of forming only one surface, spin coating or the like can be used instead of the dip coating method.

Hereinafter, the present invention will be described in more detail with reference to specific experimental examples.

(Experimental Example)

15 ml of chloroform and 5 g of PMMA are added to a 20 ml glass vial and stirred for 24 hours using a magnetic bar. After taking 3 ml of the above PMMA solution, take 1.0-2.5 ml of CuInS ₂ / ZnS quantum dots dispersed in chloroform having an absorption wavelength of 450 nm at an absorption wavelength of 3.0 nm. The thus obtained PMMA quantum dot solution is sonicated for 30 minutes to be dispersed. In addition to the CuInS ₂ / ZnS quantum dots used in this experiment, various quantum dots such as ZnCdSe / ZnS and InP / ZnS can be substituted.

The dispersed PMMA quantum dot solution is placed in an aluminum plate and dried in a vacuum oven at 25 ° C. for 12 hours in a vacuum oven. It is then further dried for 12 hours in a standard state.

The polymer thin film containing various quantum dots according to the concentration change of the quantum dots was prepared through the above process. The polymer thin film containing the quantum dots was cut and stored in a square shape having a size of 25 mm x 25 mm.

Then, 10 ml of ethanol and 7.5 g of PVP are added to a 20 ml glass vial, and the mixture is stirred for 24 hours using a magnetic bar. The polymer thin film containing the quantum dots prepared in the above solution was dip-coated and dried at 60 ° C for 1 hour to form a polymer adhesive layer.

Next, 10 ml of ethanol and 1 ml of TEOS (tetraethyl orthosilicate) were mixed and stirred for 10 minutes, 0.5 M HCl (hydrogen chloride) was added, and the mixture was stirred for 4 hours to synthesize silica sol to form a quantum dot The polymer thin film was dip-coated on a silica sol solution and dried at 60 ° C for 1 hour to form an inorganic oxide protective film to prepare a quantum dot-polymer composite plate.

Thereafter, a white light emitting diode and an RGB light emitting diode can be easily manufactured by performing a step of cutting the QWP-polymer composite plate to a size of 5 mm x 5 mm and adhering it on the LED chip with an adhesive (? -Cyanoacrylic acid ester).

A white LED (Experimental Example 1) can be made by applying a CuInS ₂ / ZnS quantum dot-polymer composite plate to a blue LED chip. When light of a wavelength of 455 nm is generated from a blue LED chip, light of a wavelength band of 590 nm is generated in the CuInS ₂ / ZnS quantum dots absorbing the light, and the two lights of different wavelengths are mixed to output white light. 20 mA was applied to Experimental Example 1 to measure the change of the EL emission intensity of the quantum dot according to the driving time. In order to more easily compare the improved stability of the white LED based on the QD-polymer composite plate, the LED sample (Comparative Example 1) in which the QDs were mixed with the silicone resin in accordance with the conventional method (Comparative Example 1), the polymer including the QD without the inorganic oxide thin film A sample using a thin film as a sealing material (Comparative Example 2), and a sample using a glass substrate as an inorganic oxide protective film according to the present invention (Experimental Example 2).

Experimental Example 1 Fabricated by the Method described above Electroluminescence characteristics were confirmed on an integrating sphere using a fluxmeter (PSI Co. ltd) by applying 20 mA, and UV-visible light The transmittance was measured using an absorption spectroscopy (Shimadzu, UV-2450).

The change in the transmittance spectrum according to the concentration of the quantum dots in the same quantum dot-polymer composite plate is shown in FIG. The permeability of the quantum dot-polymer composite plate, which is made with a relatively low concentration of 1.0 ml of Qdots, decreases as the concentration increases to 2.5 ml with high permeability.

5 shows the EL spectrum according to the quantum dot concentration in a white LED based on a CuInS ₂ / ZnS quantum dot-polymer composite plate according to the present invention. 5 (a) shows a case where the quantum dot is 1 ml, (b) shows 1.5 ml, (c) shows 2 ml, and (d) shows 2.5 ml. As the concentration of the quantum dot increases, it can be seen that the emission wavelength of 455 nm generated in the blue LED chip is further converted to the emission wavelength of the quantum dot at 590 nm.

As shown in the table included in FIG. 5, the white LED based on the quantum dot-polymer composite plate exhibits a luminance efficiency of 48 lm / W at 40 lm / W according to the change of the quantum dot concentration, The color rendering index has a distribution ranging from 59 to 71. When the CuInS ₂ / ZnS concentration was 1.5 ml, the nearest white color was observed with a color rendering index of 71. Further, all the quantum dot-polymer composite plate-based white LEDs exhibited a light conversion efficiency of 50% have. 4 and 5, it can be seen that the transmittance and the color rendering index can be adjusted according to the quantum dot concentration.

FIG. 6 is a photograph of a color rendering index, a color temperature, a CIE color coordinate of a white LED based on a quantum dot-polymer composite plate using 1.5 ml CuInS ₂ / ZnS quantum dot, and a white LED when driven at 20 mA.

When 1.5 ml of CuInS ₂ / ZnS quantum dots are used, the highest color rendering index 71 is obtained as shown in FIG. 5, and the color temperature is 4632K and the CIE color coordinates of (0.3427, 0.2682) are shown. The white LED using CuInS ₂ / ZnS quantum dot-polymer composite plate showed a luminous efficiency of 42 lm / W when a current of 20 mA was applied and a 455 nm blue LED with an efficiency of 19.2 lm / W was used. The emission image of the white LED based on the quantum dot-polymer composite plate is also shown in FIG.

FIG. 7A is a graph showing the results of a comparison between a white LED (Comparative Example 1) prepared by mixing a quantum dot with a silicone resin according to a conventional method, and a white LED using a CuInS ₂ / ZnS quantum dot-polymer thin film having no inorganic oxide thin film Comparative Example 2) was applied with 20 mA, and the change in EL spectrum according to the driving time was measured from 0 to 20 hours.

FIG. 7 (b) is a graph showing EL spectra of each of the EL devices according to the driving time from 0 to 20 h of Comparative Example 2. FIG. It can be seen from the spectrum that the LED's photoconversion efficiency decreases over time. It can be seen from the table in FIG. 7 that both the optical efficiency and the light conversion efficiency are reduced in Comparative Examples 1 and 2. However, the device of Comparative Example 2 was superior to the device of Comparative Example 1 in terms of device stability, and the decrease in the EL spectrum was not significant.

8 (a) is a photograph of a CuInS ₂ / ZnS quantum dot-polymer thin film measured by an optical microscope. FIG. 8 (b) is a photograph of a PVP film as a polymer adhesive layer applied to a CuInS ₂ / ZnS quantum dot-polymer thin film. It can be seen that the PVP film is very thin and uniformly coated. 8 (c) shows a case where the silica coating is performed once, and FIG. 8 (d) shows the case where the silica coating is performed three times. Referring to FIG. 8 (c), it can be seen that a relatively thin, uniform and transparent silica film is formed. In Figure 8 (d), surface cracks can be observed along with rough surface morphology due to excessive silica thickness increase.

Fig. 9 (a) shows the change of the EL spectrum at 20 mA according to the driving time for the case where silica is coated as the inorganic oxide protective film (Experimental Example 1) and when the glass substrate is sealed with the glass substrate (Experimental Example 2). Even though the driving time was prolonged to 15 hours, the decrease of the EL spectrum of the LED was hardly observed in both cases, and the light efficiency and the light conversion efficiency also maintained almost the initial value over time. Can be confirmed.

9 (b) is the case of Experimental Example 1, and it can be seen that the EL spectrum does not change even after the elapse of time from 0 to 15 h, and through the table included in FIG. 9, Can not be reduced. It can be confirmed that oxidation and ligand desorption at the surface of the quantum dots by moisture and oxygen in the atmosphere can be prevented by forming an inorganic oxide protective film using silica. Therefore, as shown in FIG. 7, the EL spectrum of the LED is not abruptly decreased. As a result, when the LED is fabricated using the quantum dot-polymer composite plate, the LED having better stability It is possible to fabricate.

The quantum dot-polymer composite plate was fabricated by changing the concentration of yellow emission CuInS ₂ / ZnS quantum dots. FIG. 10 (a) is a sample photograph accordingly. In addition, a quantum dot-polymer composite plate can be fabricated using a green luminescent ZnCdSe / ZnS quantum dot, and FIG. 10 (b) is a sample photograph accordingly. Therefore, it can be seen from the sample photographs of FIG. 10 that a quantum dot-polymer composite plate can be manufactured using various quantum dots.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation in the embodiment in which said invention is directed. It will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the appended claims.

Claims (11)

A free-standing polymer thin film including quantum dots that convert wavelength of excitation light of a light emitting diode to generate wavelength conversion light; And
A quantum dot-polymer composite plate comprising an inorganic oxide protective film formed on at least one side of the polymer thin film,
A quantum dot-polymer composite plate as an encapsulant for bonding an LED package made of a semiconductor laminate to an LED package. The quantum dot-polymer composite plate according to claim 1, wherein the inorganic oxide protective film is a thin film or glass of a material selected from the group consisting of SiO ₂ , TiO ₂ , Al ₂ O _3, and mixtures thereof. The quantum dot-polymer composite plate according to claim 1, further comprising a polymer adhesive layer between the polymer thin film and the inorganic oxide protective film. The quantum dot-polymer composite plate according to claim 3, wherein the polymeric adhesive layer is PVP (polyvinylpyrrolidone) or PVA (polyvinyl alcohol). Preparing a polymer solution by dissolving the polymer in an organic solvent;
Mixing quantum dots that convert wavelength of excitation light of the light emitting diode and generate wavelength conversion light into the polymer solution;
Drying the polymer solution mixed with the quantum dots to form a free-standing polymer thin film containing quantum dots; And
And forming an inorganic oxide protective film on at least one surface of the polymer thin film,
A method of manufacturing a quantum dot-polymer composite plate as an encapsulant for bonding an LED package comprising a semiconductor laminate to an LED package. The method of claim 5, wherein the inorganic oxide protective film is _{SiO 2, TiO 2, Al 2} O 3 , and quantum dots, characterized in that the thin film, or a glass of a material selected from the group consisting of the mixture method of preparing the polymer composite plates. [6] The method of claim 5, further comprising forming a polymer adhesive layer between the polymer thin film and the inorganic oxide protective film. [8] The method of claim 7, wherein the step of forming the polymer adhesive layer comprises dip coating the polymer thin film in an ethanol solution in which PVP or PVA is dissolved and drying the polymer thin film. . [6] The method of claim 5, wherein the step of forming the inorganic oxide protective layer comprises dip coating the polymer thin film in a silica sol solution and drying the polymer thin film. A light emitting diode comprising a semiconductor laminate; And
A light-emitting device comprising the quantum dot-polymer composite plate according to claim 1. Providing a light emitting diode comprising a semiconductor laminate; And
And bonding the quantum dot-polymer composite plate according to claim 1 onto the light emitting diode.

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