KR101735445B1 - Layer of high and low refractive index organic-inorganic hybrid materials and manufacturing method of OLEDs, OLEDs made thereby - Google Patents

Abstract

The present invention relates to a laminate for OLED devices using a high-refractive and low-refractive organic/inorganic hybrid material, a method of manufacturing an OLED device and an OLED device prepared thereby. The laminate for an OLED element forms an inner light extraction layer or an outer light extraction layer on a transparent substrate and one surface of the transparent substrate, and the inner light extraction layer or the outer light extraction layer is a scattering region formed by coating a high-refractive or low-refractive organic/inorganic hybrid material. The high-refractive or low-refractive organic/inorganic hybrid material, as the precursor (P), is mixed with titanium or silica-based refractive index functional metal alkoxide by using copolymerization of methyl methacrylate (MMA) and 3-(trimethoxysilyl) propyl methacrylate (MSMA), as well as a sol-gel method for the precursor (P). The laminate for OLED devices according to the present invention reduces the refractive index difference by SiO_2 and TiO_2 nanoparticles, thereby enhancing light scattering.

Description

Technical Field [0001] The present invention relates to a laminate for an OLED device using a high-refraction and low-refractive organic / inorganic hybrid material, a method for manufacturing an OLED device, and an OLED device manufactured by the method. thereby}

The present invention relates to a laminate for an OLED device using a high-refraction and low-refraction organic / inorganic hybrid material, a method of manufacturing an OLED device, and an OLED device manufactured thereby.

Among many display elements, organic light emitting diodes (OLEDs) have been regarded as promising next-generation displays for potential applications of lighting, flat displays. OLEDs have unique characteristics such as low power consumption, wide viewing angle, excellent color reproducibility, high contrast, fast response and flexibility.

However, the power and current efficiency of OLEDs is still insufficient for certain applications such as smart phones, tablet PCs and lighting. OLED light extraction technology has recently become an important issue to achieve high efficiencies such as fluorescent tubes and other lighting technologies such as LEDs.

The internal quantum efficiency of an OLED can reach 100% by introducing a phosphorescent mechanism, but the light extraction efficiency of a backside OLED is usually about 20%. the light loss occurs due to the refractive index difference between the air / substrate and the substrate / indium tin oxide (ITO) interface, and the light loss is affected by the total reflection of the substrate. Light emitted from the inside usually undergoes total internal reflection, and light reflected from the inside of the device is increased to be trapped in most devices. A method for enhancing the external quantum efficiency (EQE) is to reduce the refractive index difference by introducing an extraction layer and to break the condition of the total reflection.

Recently, several studies have been reported on improving the light extraction of OLEDs using external or internal light extraction layers. The inner light extracting layer is located between the transparent conductive film (TCO) and the glass substrate, and the outer light extracting layer is located outside the element substrate.

The external light extraction layer located outside the device substrate with the micro / nano structure can be reassigned so that the light reflected by the total reflection at the substrate / air interface does not interfere with the device. On the other hand, the micro / nano structure inner light extraction layer between the substrate and the ITO anode layer can interfere with total reflection in both the substrate and the waveguide mode.

Therefore, the light extraction efficiency of the OLED including the inner light extracting layer will be higher than that including the outer light extracting layer. The current technology for introducing a light extraction layer into an OLED is to mix the inorganic particles with the polymer and adjust the refractive index to increase light scattering. However, the inorganic particles are sometimes not well dispersed and generate high roughness and wavy surfaces, which shortens the performance and life of the device.

Another problem in introducing the light extracting layer is low transmittance. The dispersive power of polymer particles is an important problem. The agglomeration of the inorganic particles reduces the transmittance of the light extracting layer, so as not to improve the light extraction of the OLED. In order to improve the external light extraction efficiency of the OLED, the inner and outer light extracting layers are required to reduce the refractive index difference between the substrate / ITO and the air / glass interface at low roughness, high transmittance, low refractive index and high refractive index.

In order to solve the problems of the prior art, the present inventors have synthesized an organic-inorganic hybrid material by a sol-gel process together with a tetraethylorthosilicate (TEOS) and an alkoxide material containing Ti together with a high-refraction and a low- The present invention has been completed by applying the present invention to an OLED.

Accordingly, it is an object of the present invention to provide a laminate for OLED devices using a high-refraction or low-refractive organic / inorganic hybrid material.

Another object of the present invention is to provide a method of manufacturing an OLED device including the above-described laminate for an OLED element.

Another object of the present invention is to provide a high-refraction or low-refractive green light emitting OLED device manufactured by the above method.

Another object of the present invention is to provide a display device manufactured using the high-refraction or low-refractive green light emitting OLED device.

Another object of the present invention is to provide a surface-emitting light source manufactured using the high-refraction or low-refractive green light-emitting OLED device.

According to an aspect of the present invention,

A laminate for an OLED element which forms an inner light extraction layer or an outer light extraction layer on one surface of the transparent substrate,

The inner light extracting layer or the outer light extracting layer is a scattering region formed by coating a high-refraction or low-refractive organic / inorganic hybrid material,

The high refractive index or low refractive organic / inorganic hybrid material may include methyl methacrylate (MMA) and 3- (trimethoxysilyl) propyl methacrylate (MSMA) as precursors (P) And a refractory functional metal alkoxide based on titanium or silica using a sol-gel method to the precursor (P). The present invention also provides a laminate for an OLED device using the organic / inorganic hybrid material .

According to another aspect of the present invention, there is provided a method of manufacturing an OLED device including the stack for OLED elements.

According to another aspect of the present invention, there is provided a high-refraction or low-refractive green light emitting OLED device manufactured by the method of manufacturing an OLED device.

According to another aspect of the present invention, there is provided a display device manufactured using the high-refraction or low-refractive green light emitting OLED device.

According to another aspect of the present invention, there is provided a surface emitting light source manufactured using the high-refraction or low-refractive green light emitting OLED device.

Since the stack for OLED devices according to the present invention includes a scattering region composed of an inner light extracting layer or an outer light extracting layer, the refractive index difference is reduced by SiO ₂ and TiO ₂ nanoparticles to enhance light scattering, There is an effect of increasing extraction.

In addition, there is an effect that the efficiency, the luminance, and the life of the OLED device can be increased.

Further, there is an advantage that the OLED device of the present invention can be easily mass-produced with a simple process and a low cost.

1 is a schematic diagram of an OLED element according to an embodiment of the present invention.
2 is a graph illustrating transmittance and haze of an inner light extracting layer and an outer light extracting layer according to an embodiment of the present invention.
FIG. 3 is a top-down SEM photograph of a precursor, an inner light extracting layer, and an outer light extracting layer according to an embodiment of the present invention.
FIG. 4 is a graph showing surface images of ITO / glass and ITO / internal light extraction layer / glass according to an embodiment of the present invention, measured by a 3D optical analyzer.
FIG. 5 is a graph illustrating an optimum transmittance according to thickness of an ITO / internal light extraction layer / glass substrate according to an embodiment of the present invention. Referring to FIG.
6 is a graph illustrating light extraction characteristics of a device according to an exemplary embodiment of the present invention.
7 is a graph illustrating light extraction characteristics of a device according to an embodiment of the present invention.
FIG. 8 is a photograph illustrating light emission of a device according to an embodiment of the present invention when the device is turned on.

Hereinafter, the present invention will be described in detail.

The present invention relates to a laminate for an OLED device using a high-refraction and low-refraction organic / inorganic hybrid material, a method of manufacturing an OLED device, and an OLED device manufactured thereby.

Specifically, according to one aspect of the present invention, a laminate for an OLED device using the high-refraction and low-refractive organic /

A laminate for an OLED element which forms an inner light extracting layer or an outer light extracting layer on one surface of the transparent substrate, wherein the inner light extracting layer or the outer light extracting layer is a high refractive index or low refractive index organic / inorganic hybrid material (MMA) and 3- (trimethoxysilyl) propyl methacrylate (PMA) as a precursor (P), and the high refractive index or low refractive organic / inorganic hybrid material, which is prepared by bonding a copolymer of titanium (trimethoxysilyl) propyl methacrylate (MSMA) and a titanium or silica-based refractive index functional metal alkoxide to the precursor (P) by a sol-gel method .

As the transparent substrate, a material having a high transmittance to visible light is used. As the material having high transmittance, a glass substrate or a plastic substrate can be used, and a glass substrate is preferably used.

In addition, the functional metal alkoxide is a titanium-based metal alkoxide when it is a high-refraction material, and is a silica-based metal alkoxide when it is a low-refraction material. Preferably, the functional metal alkoxide is TTIP (Titanium (IV) isopropoxide) for a high-refraction material and TEOS (tetraethyl orthosilicate) for a low-refraction material.

The high refractive index material is included in the inner light extracting layer, and the low refractive index material is included in the external light extracting layer. Since the high refractive index material can reduce the refractive index difference between the substrate and ITO, it is included in the inner light extracting layer, and the low refractive index material can reduce the refractive index difference between the external air and the substrate. .

The scattering region is characterized by including a scattering element composed of TiO ₂ nanoparticles or SiO ₂ nanoparticles. The scattering element is totally reflected at the boundary between the light-transmitting substrate and the air, as well as the light incident directly into the light extracting layer, that is, the light directly incident from the organic layer, and the light entering the inner light extracting layer is randomly scattered by a plurality of scattering elements In this process, light having an incident angle less than the critical angle is emitted to the outside of the transparent substrate, thereby improving light extraction efficiency.

In addition, the inner light extracting layer and the outer light extracting layer And has a thickness in the range of 100 to 800 nm. The thinner the thickness of the light extracting layer is, in terms of decreasing the light absorbance and increasing the light transmittance, it is necessary to consider the minimum thickness required to maintain the flatness of the surface of the light extracting layer. Therefore, it is preferably 350 nm. When the thickness of the inner light extracting layer and the outer light extracting layer is 350 nm or less, light loss occurs due to back reflection, and when the thickness is 400 nm or more, light loss occurs due to back scattering I can not.

According to another aspect of the present invention,

A method of manufacturing an OLED device including the stack for OLED elements,

A first step of preparing high refractive index or low refractive organic / inorganic hybrid material; A second step of forming an inner light extracting layer or an outer light extracting layer by coating a high refractive index or low refractive organic / inorganic hybrid material on one surface of the translucent substrate; In the second step, ITO, an organic layer, and a cathode are successively stacked on the upper surface of the transparent substrate on which an external light extracting layer is formed by coating an upper surface or a lower refractive material of the internal light extracting layer formed by coating a high refractive index material on one surface of the transparent substrate And a third step of manufacturing an OLED device.

According to still another aspect of the present invention,

There is provided a high-refraction or low-refractive green light emitting OLED device manufactured by the method of manufacturing an OLED device.

According to still another aspect of the present invention,

And a display device manufactured using the high-refraction or low-refractive green light-emitting OLED device.

According to still another aspect of the present invention,

And a surface emitting light source manufactured using the high refractive index or low refractive green emitting OLED device.

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

It is to be understood by those skilled in the art that these embodiments are only for describing the present invention in more detail and that the scope of the present invention is not limited by these embodiments in accordance with the gist of the present invention .

Example

Example 1 Synthesis of poly (MMA-co-MSMA) precursor.

MMA (1.001 g, 0.01 mole) and MSMA (0.828 g, 0.003 mole) were combined with BPO (0.121 g, 0.001 mole, a reaction initiator) in THF (21 mL ) Were polymerized in a three-neck round flask.

Example 2 Synthesis of High Refractive Hybrid Material.

TTIP (16.461 g, 0.058 mole, 90 wt%), deionized water (1.04 mL) and THF (338.7 mL) were added to the precursor solution and stirred at 60 ° C for 2 h. The amount of water was adjusted so that the ratio of TTIP to water was 1: 1 mole.

Example 3: Synthesis of a low refractive hybrid material.

For the synthesis of low refractive materials, ethanol (17 ml) was used as a solvent because the by-product in the sol-gel process is alcohol and TEOS is highly soluble in ethanol. The process for synthesizing a precursor of a low refractive material is the same as that for producing a high refractive material except that ethanol is used instead of THF solvent and the reaction temperature is 70 ° C. Deionized water (0.18 mL), TEOS (2.778 g, 0.013 mole) and 2.5 M NaCl (0.015 g) were added to the precursor solution and stirred at 70 ° C for 2 h.

Example 4: Preparation of OLED device.

In the present invention, three kinds of OLED devices were manufactured. 1 (a) is a reference device, FIG. 1 (b) is an element including an external light extraction layer, FIG. 1 (c) Layer. The outer and inner light extraction layers of the OLED device were coated with a spin-coating of low refractive and high refractive hybrid materials.

Example 4-1 is a reference device in which glass green ITO (140 nm) / NPB (100 nm) / Alq3: C545T (40 nm) / Alq3 (25 nm) / LiF (1 nm) / Al (120 nm). NPB was used as a hole transporting layer, Alq3 doped with 3 wt% C545T as a light emitting layer, Alq3 as an undoped electron transporting layer, LiF as a hole injection layer, and high refractive Al as a cathode. The deposition rate of the organic layer was maintained at ~ 0.1 nm / s. The organic and metal layers were vacuum deposited in a vacuum chamber and the pressure was <10 ^-6 torr. The deposition area of the device was 2 x 2 mm ² . Sputtering of ITO was performed at 49.5 sccm of Ar, 0.11 sccm of O2 and 994 W of radio frequency power. A transparent ITO electrode with a sheet resistance of 35 Ω / sq was deposited on the glass.

Example 4-2 for an external light extracting structure The device was introduced as an external light extracting layer with a low refractive index on the outer surface of the glass substrate of Example 4-1. The low refractive hybrid material was spin-coated on a glass substrate at 500-5000 rpm for 40 seconds, left at 80 ° C for 2 hours, washed several times with water to remove NaCl.

Example 4-3 The device was manufactured by inserting a high refractive index material as an internal light extracting layer between the ITO of the device of Example 4-1 and the glass substrate as an internal light extracting structure. The high-refractive-index hybrid material was spin-coated on a glass substrate at 500-5000 rpm for 40 seconds and left at 80 ° C for 2 hours. A transparent ITO electrode with a sheet resistance of 35 Ω / sq was directly deposited on the substrate coated with high refractive index material by radio frequency magnetron sputtering.

The structure of the fabricated device is shown in the following Examples 4-1 to 4-3.

Example 4-1: The device was fabricated with glass / ITO (140 nm) / NPB (100 nm) / Alq3: C545T (40 nm) / Alq3 (25 nm) / LiF (1 nm) / Al (120 nm).

Example 4-2: The device was fabricated with an external light extraction layer / glass / ITO (140 nm) / NPB (100 nm) / Alq3: C545T (40 nm) / Alq3 (25 nm) / LiF (1 nm) / Al (120 nm).

Example 4-3: Alq3: C545T (40 nm) / Alq3 (25 nm) / LiF (1 nm) / Al (120 nm)

Also, in order to analyze the characteristics of the fabricated device, the microstructure of the low-refraction and high-refraction hybrid materials was measured with a scanning electron microscope (FE-SEM, S-4800, Hitachi, Japan). The transmittance and haze of the thin film were measured with a UV spectrophotometer (CM-3600d, Konica Minolta Co., Japan) and the wavelength was found to be 360 to 740 nm. The refractive index and extinction coefficient of the thin film were measured by a spectroscopic ellipsometer (Elli-SE-U, Ellipsotechnology Co., Korea), and the wavelength was found to be 355 to 1030 nm.

The samples were prepared by spin coating a glass substrate with a spectrophotometer and a UV spectrophotometer. The surface roughness and thickness of the light extraction layer were measured with a 3D optical analyzer (Nano-view NV-E1000, Nano system Co., Korea). The IVL characteristics of fabricated OLED devices were measured with a spectrophotometer (PR-650, LMS Corp., Korea) in a black box under normal atmospheric conditions.

Hereinafter, the results of the above embodiments will be described with reference to the drawings.

1. Optical properties

Table 1 below summarizes the refractive index and extinction coefficient of the inner and outer light extraction layers at 550 nm.

Inner light extraction layer External light extraction layer Refractive index 1.81 1.44 Extinction coefficient 2.4 x 10 ^-2 9.58 x 10 ^-3

Referring to Table 1, the refractive index of the internal light extracting layer increased from 1.50 to 1.81 when 90 wt% TTIP was added, and the refractive index decreased from 1.50 to 1.44 when the external light extracting layer was added with 2.5M NaCl. The increase and decrease of the refractive index is due to the relatively heavier TiO ₂ particles and relatively lighter SiO ₂ than the precursor atoms. When the amounts of TTIP and NaCl in the mixed solution for the inner and outer light extracting layers are more than 90 wt% and 2.5M respectively, the TiO ₂ and SiO ₂ particles will be precipitated by the gelation of the reactants. In the case of conventional backside OLEDs, the loss of light is due to the difference in refractive index between indium tin oxide (ITO) / glass substrate and glass substrate / air. If high refractive index and low refractive index hybrid materials are applied to the outer and inner light extraction layers of an OLED, the light extraction efficiency of the OLED will be significantly improved as the refractive index difference is reduced.

FIGS. 2 and 3 are graphs showing the transmittance and haze and the top-down SEM photographs of the high-refraction hybrid material and the low-refractive hybrid material synthesized in Example 1 and Example 2, respectively.

Referring to FIG. 2, the transmittance and haze of the precursor copolymer were 92.0 and 0.2% for poly (MMA-co-MSMA) on the glass substrate, respectively. The above values were similar to the transmittance and haze values of pure glass substrates of 91.3 and 0.2%. The transmittance and haze of the 750 nm thick inner light extraction layer decreased and increased to 85.4 and 13.1%, respectively. The transmittance and haze of the 800 nm thick external light extraction layer decreased and increased to 89.3% and 23.8%, respectively. The decrease in transmittance and the increase in haze in the inner light extraction layer and the outer light extraction layer are due to light scattering by titanium and silica particles in the poly (MMA-co-MSMA) matrix. The transmittance and the haze value are summarized in Table 2 below.

Transmittance haze Example 1 92.0% 0.2% Example 2 85.4% 13.1% Example 3 89.3% 23.8%

FIG. 3 (a) is a top view, FIG. 3 (b) is an inner light extraction layer, and FIG. 3 (c) is a top-down SEM photograph of an outer light extraction layer. Referring to FIG. 3, the SEM photograph of the precursor of FIG. 3 (a) shows a featureless form, while the inner light extracting layer of FIG. 3 (b) and the outer light extracting layer of FIG. 3 Uniform, spherical inorganic particles having diameters of 118.7 ± 32.5 nm and 125.3 ± 21.5 nm, respectively. When the inorganic spherical particles are applied to an OLED, the emitted light can be efficiently extracted and the refractive index can be adjusted, thus positively affecting the inner and outer light extraction layers. The diameters of the inorganic spherical particles were measured and are shown in Table 3 below.

Inorganic spherical particle diameter (nm) Example 1 - Example 2 118.7 ± 32.5 Example 3 125.3 ± 21.5

2. Characteristic properties

4 (a) and 4 (b) show the surface images of ITO / glass and ITO / internal light extraction layer / glass measured by a 3D optical analyzer.

Referring to FIG. 4, the roughness (R _a s) of the ITO thin film without the inner light extracting layer and the roughness of the glass substrate were 1.05 ± 0.09 and 0.85 ± 0.04 nm, respectively. The roughness of the inner light extraction layer and the glass substrate were 1.92 ± 0.28 and 1.52 ± 0.34 nm, respectively. The organic-inorganic hybrid thin film as described above has better planarity than the conventional manufacturing method. Planarity of the surface plays an important role in OLED application. If the surface is rough or curved, the performance of the device is deteriorated and the life time is shortened. Planar layers deposited by plasma enhanced chemical vapor deposition (PECVD) and chemical mechanical polishing (CMP) are introduced to improve planarity over the light extraction layer. The measured values of the roughness of the ITO thin film and the glass substrate are summarized in Table 4 below.

pellicle Roughness (R _a s) ITO 1.05 0.09 nm glass 0.85 ± 0.04 nm ITO + internal light extraction layer + glass 1.92 ± 0.28 nm internal light extraction layer + glass 1.52 + - 0.34 nm

3. Optimization for thickness

5 is a graph showing the optimum transmittance according to the thickness of the ITO / internal light extraction layer / glass substrate.

Referring to FIG. 5, the highest values were found at 200, 400 and 600 nm, and the minimum values were found at 100, 300 and 500 nm. The transmittance of FIG. 5 oscillates as the thickness of the inner light extracting layer increases, which is due to constructive interference and destructive interference. The transmittance showed a maximum transmittance at 200 nm, which is similar to that of the ITO film alone. The above results show that the loss of transmittance can be minimized by controlling the thickness of the inner light extracting layer. The thickness, transmittance, refractive index and extinction coefficient of the ITO thin film were 140 nm, 78.4%, 2.07 and 2.3 × 10 ^-2 , respectively, and the transmittance of ITO / internal light extraction layer / glass structure was calculated using the above values .

4. Light extraction of the OLEDs

FIGS. 6 and 7 are graphs showing light extraction characteristics of the device manufactured in Examples 4-1 and 4-2. FIG.

6A to 6D show luminance, power, current efficiency, and EL spectrum according to voltages of Examples 4-1 and 4-2, respectively .

6, when the thickness of the external light extracting layer is 350 nm, the luminance, power and current efficiencies of the device of Example 4-2 are 16780 cd / m ² at 14 V and 5.80 lm / W at 4 V, respectively In the case of the device of Example 4-1, it was 13830 cd / m ² at 14 V, 4.51 lm / W at 4 V and 5.55 cd / A at 4 V, respectively. In the case of luminance, power and current efficiency, it can be seen that the device of Example 4-2 is strengthened by 21.3, 28.6 and 29.1% more than the device of Example 4-1, respectively. FIG. 6D shows that the enhancement of the luminance appears in the entire spectral range, and the shape of the EL spectrum and the peak of the wavelength are increased by the insertion of the external light extraction layer. The light extraction depends on the concentration of scattering particles and the path of the light extraction layer. The path of the light extracting layer depends on the thickness of the layer. When the scattering particle concentration is low and the path of the light extracting layer is short, back reflection occurs to the inside of the device at the interface and large light loss occurs. When the scattering particle concentration is high and the path of the light extraction layer is long, back scattering is a main cause of light loss. In the case of the effect of the thickness of the light extraction as described above, the optimal thickness of the light extracting layer at 350 nm will be given. Thus, the external light extraction layer plays a positive role in increasing the light extraction of the OLED because it reduces the refractive index difference between SiO ₂ nanoparticles well dispersed in the glass substrate and air and in the external light extraction layer, To enhance the scattering. The measured values of the light extraction characteristics of the OLED are summarized in Table 5 below.

device Luminance Power Current efficiency
(current efficiency) Example 4-1 13830 cd / m ² 4.51 lm / W 5.55 cd / A Example 4-2 16780 cd / m ² 5.80 lm / W 7.17 cd / A

7 (a) - (d) show luminance, power, current efficiency and EL spectrum according to the voltages of Examples 4-1 and 4-3, respectively.

Referring to FIG. 7, in terms of luminance, power, and current efficiency, the maximum light extraction has a maximum value when the thickness is 400 nm. The luminance, power and current efficiency of the device were found to be 22460 cd / m ² at 14 V, 7.98 lm / W at 4 V, and 8.84 cd / A at 4 V, respectively. In the case of 14 V, 13830 cd / m ² , 4.51 lm / W at 4 V and 5.55 cd / A at 4 V, respectively. In the case of luminance, power and current efficiency, it can be seen that the device of Example 4-3 is further enhanced by 62.4, 76.9 and 59.2% than the device of Example 4-1. 7D shows EL spectra according to the thicknesses of the inner light extracting layers of the devices of Examples 4-1 and 4-3. The EL intensity increases in the entire spectral range and has a maximum at 400 nm when an internal light extraction layer is introduced. The measured values of the light extraction characteristics of the OLED are summarized in Table 6 below.

device Luminance Power Current efficiency
(current efficiency) Example 4-1 13830 cd / m ² 4.51 lm / W 5.55 cd / A Example 4-3 22460 cd / m ² 7.98 lm / W 8.84 cd / A

5. Emitting light of OLED

8 (a) - (c) are photographs of light emission when the devices of Examples 4-1 to 4-3 are turned on.

8, the light emitting region of the device of Example 4-2 is wider than the light emitting region of the device of Example 4-1, since the light extracted by the glass is directly scattered by the TiO ₂ nanoparticles of the external light extracting layer to be. It can be seen that the emission of the device of Example 4-3 is stronger than that of the device of Example 4-1 because the light trapped in the ITO layer and the organic layer is emitted by the inner light extracting layer.

Table 7 below shows the CIE1931 (x, y) coordinates of the devices of Examples 4-1 to 4-3.

device  CIE (x)  CIE (y) Example 4-1 0.3022 0.6333 Example 4-2 0.3004 0.6348 Example 4-3 0.3013 0.6341

Referring to Table 7, the CIE (x, y) of the device of Example 4-2 and the device of Example 4-3 were similar to those of Example 4-1, and the effect of the inner and outer light extracting layers And it can be seen that the inner and outer light extracting layers exhibit a stable color.

The present invention relates to a process for the preparation of an organo-silane coupling agent by acid-free sol-gel process of methyl methacrylate (MMA) and 3- (trimethoxysilyl) propyl methacrylate (MSMA) (poly (MMA- The inorganic hybrid material was synthesized as a precursor, and titanium (IV) isopropoxide (TTIP) and TEOS were used as the high and low refractive materials together with the precursor. When 90 wt% TTIP, 2.5M NaCl, and 1.50 precursor were added, the refractive index increased to 1.81 and decreased to 1.44. The high-refraction and low-birefringence hybrid materials as described above were used for the inner and outer light extraction layers. The luminance, power and current efficiencies of the devices including the external light extraction layer were 21.3, 28.6 and 29.1% higher than those of the reference device, and the luminance, power and current efficiencies of the devices including the internal light extraction layer were 62.4, 76.9 and 59.2%, respectively. It can be seen that the inner and outer light extraction layers of the present invention are effective in reducing the total reflection of the substrate by reducing the refractive index of the substrate / ITO and air / glass interfaces. It is also known that the TiO ₂ and SiO ₂ nanoparticles The light scattering by the OLED has enhanced the light extraction efficiency of the OLED. It can be confirmed that high refractive index and low refractive index materials are useful for improving light extraction efficiency.

The present invention has been described above with reference to preferred embodiments. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. The disclosed embodiments should, therefore, be considered in an illustrative rather than a restrictive sense. The scope of the present invention is defined by the appended claims rather than by the foregoing description, and all differences within the scope of equivalents thereof should be construed as being included in the present invention.

Claims (10)

A laminate for an OLED element which forms an inner light extraction layer or an outer light extraction layer on one surface of the transparent substrate,
The inner light extracting layer or the outer light extracting layer is a scattering region formed by coating a high-refraction or low-refractive organic / inorganic hybrid material,
The high refractive index or low refractive organic / inorganic hybrid material may include methyl methacrylate (MMA) and 3- (trimethoxysilyl) propyl methacrylate (MSMA) as precursors (P) And a titanium or silica-based refractive index functional metal alkoxide with a sol-gel method to the precursor (P)
Wherein the inner light extracting layer and the outer light extracting layer comprise spherical inorganic particles having diameters of 118.7 ± 32.5 nm and 125.3 ± 21.5 nm, respectively. The method according to claim 1,
Wherein the functional metal alkoxide is a titanium-based metal alkoxide in the case of a high-refraction material, and the silica-based metal alkoxide is in the case of a low-refraction material. The method according to claim 1,
Wherein the functional metal alkoxide is TTIP (Titanium (IV) isopropoxide) in the case of a high-refraction material and TEOS (tetraethyl orthosilicate) in a case of a low-refraction material. The method according to claim 1,
Wherein the high refractive index material is contained in an inner light extracting layer and the low refractive index material is contained in an external light extracting layer. The method according to claim 1,
Wherein the scattering region comprises a scattering element made of TiO ₂ nanoparticles or SiO ₂ nanoparticles. 5. The method of claim 4,
Wherein the inner and outer light extraction layers have a thickness in the range of 100 to 800 nm. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt; A first step of preparing high refractive index or low refractive organic / inorganic hybrid material;
A second step of forming an inner light extracting layer or an outer light extracting layer by coating a high refractive index or low refractive organic / inorganic hybrid material on one surface of the translucent substrate;
In the second step, ITO, an organic layer, and a cathode are successively stacked on the upper surface of the transparent substrate on which an external light extracting layer is formed by coating an upper surface or a lower refractive material of the internal light extracting layer formed by coating a high refractive index material on one surface of the transparent substrate And a third step of manufacturing an OLED device
Wherein the inner light extracting layer and the outer light extracting layer each comprise spherical inorganic particles having diameters of 118.7 ± 32.5 nm and 125.3 ± 21.5 nm, respectively. 9. A high-index or low-refractive green light-emitting OLED device according to claim 7. 9. A display device manufactured using the green light emitting OLED device according to claim 8. 9. A surface emitting light source according to claim 8, wherein the green light emitting OLED element is used.

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