CN102593363B - High-efficiency light-emitting electroluminescent device - Google Patents

Abstract

The invention provides an electroluminescent device with high efficiency, which includes a transparent substrate, a light-enhancing structure and an organic light-emitting diode unit. The organic light-emitting diode unit includes a transparent electrode, a light-emitting element with at least one light-emitting layer, and a reflective electrode layer. The light-enhancing structure includes a light-scattering layer, and the light-scattering layer includes a high-refractive-index matrix and a scattering dispersion, and the high-refractive-index matrix is a nanocomposite material containing inorganic nanoparticles, composed of nanoparticles and high refractive index The composition of the organic modifier; the scattering dispersion is micron-sized particles or holes whose refractive index is different from that of the matrix. The electroluminescent device of the invention has the following technical effects: 1) the light output efficiency is improved; 2) the production cost is reduced.

Description

A high-efficiency light-emitting electroluminescent device

technical field

The invention relates to an electroluminescent device, in particular to an electroluminescent device capable of improving luminous efficiency.

Background technique

Electroluminescent devices (LEDs) mainly include the following types: organic electroluminescent devices (OLEDs), polymer electroluminescent devices (PLEDs) and inorganic electroluminescent devices, such as QD-LEDs.

Existing LEDs usually include a transparent substrate, a transparent first electrode layer, a light emitting element and a reflective second electrode layer. When electrons and holes are injected from two electrons through the light-emitting element into the LED, they combine or collide together to generate light. The light-emitting element usually includes several layers of materials, including at least one light-emitting layer for emitting light. A light emitting element of an OLED generally includes an electron injection layer, an electron transport layer, one or more light emitting layers, a hole transport layer and a hole injection layer. One or several layers can be combined, one or several layers can be removed, and an electron blocking layer or a hole blocking layer can be added on their basis. Typically, the first electrode is an anode and the second electrode is a cathode.

The light refractive index of the luminescent material is generally higher than that of air, and there is usually one or more layers of materials with a refractive index between the light emitting layer and the air. Total internal reflection occurs when light passes from a high-refractive-index layer to a low-refractive-index layer. TIR light is trapped in the high-index layer and cannot be transmitted into the low-index layer. In an OLED, the light-refractive index of the light-emitting layer is 1.7-1.8, the light-refractive index of the transparent electrode layer is 1.9, and the light-refractive index of the substrate is 1.5. Total internal reflection occurs at the interface between the transparent electrode layer and the substrate, and a part of the light reaches the interface from the light-emitting layer at an angle larger than the normal critical angle. This light is trapped between the organic layer and the transparent electrode layer, and finally absorbed by the materials of each layer Or emitted from the border of the OLED, without any function, this part of the light is called organic light. Total internal reflection also occurs at the interface between the substrate and the air. A part of the light reaches the interface at an angle larger than the normal critical angle. This light is trapped between the substrate, the transparent electrode layer and the organic layer, and is finally absorbed by the materials of each layer or from the The edge of the OLED is emitted without any function, and this part of the light is called the base light. It is estimated that more than 50% of the light emitted by the light-emitting layer becomes organic light, more than 30% becomes base light, and less than 20% is output into the air and becomes usable light. The 20% of the light actually emitted from the LED is called air light, and the light traps caused by total internal reflection greatly reduce the luminous efficiency of the LED.

Various measures have also been taken to increase the luminous efficiency of thin-film LEDs by reducing the light trapping effect so that organic light and substrate light can be output from the LED. These attempts are detailed in the following documents: U.S. Patent Text. Nos. 5,955,837 , 5,834,893; 6,091,195; 6,787,796, 6,777,871; U.S. Patent Application Publication Nos.2004/0217702A1, 2005/0018431A1, 2001/0026124A1;

Generally speaking, existing measures usually provide a light-enhancing structure that can change the direction of light, so that a part of the light energy trapped due to total internal reflection can be transmitted into the air.

In most cases, these light-enhancing structures are placed on the outer surface of the transparent substrate. Since organic light can never reach these structures, these light-enhancing structures can only use air light and substrate light. Since organic light accounts for half of the emitted light, these light-enhancing structures cannot effectively increase the output of light. In order to effectively extract these three kinds of light, the light-enhancing structure must be located near the transparent electrode. The bottom emission structure in the existing invention, Setting the light-enhancing structure close to the electrode layer means that the light-enhancing structure must be placed between the transparent electrode and the substrate in the LED. Designing this internal light-enhancing structure means complex technical challenges, because unless the perfection of the thin-film LED can be guaranteed, the light-enhancing structure will Being inside an LED can lead to a number of undesirable outcomes, including dead shorting of the device. Although there are many proposals about internal light-enhancing structures, such a device with better luminous efficiency has not been achieved in the actual prior art.

Contents of the invention

The purpose of the present invention is to overcome the shortcomings of the prior art and provide an electroluminescent device that emits light with high efficiency.

The high-efficiency luminescent electroluminescent device of the present invention includes a transparent substrate, a light-enhancing structure, and an organic light-emitting diode unit. The organic light-emitting diode unit includes a transparent electrode, a light-emitting element with at least one light-emitting layer, and a reflective electrode layer. The above-mentioned The light-enhancing structure includes a light-scattering layer. The light-scattering layer includes a high-refractive-index matrix and a scattering dispersion. The high-refractive-index matrix is a nanocomposite material containing inorganic nanoparticles, which is composed of nanoparticles and high-refractive-index organically modified Body composition; the scattering dispersion is micron-sized particles or holes whose refractive index is different from that of the matrix. The light-scattering layer serves to extract light trapped in the light-emitting device through generation of light-scattering.

In the high-efficiency luminescent electroluminescent device, the light-enhancing structure is also equipped with a high-refractive index smooth surface layer. A surface smoothing layer is used to further improve surface smoothness.

In the high-efficiency light-emitting electroluminescence device, the organic light-emitting diode unit further includes an anti-short circuit layer.

In the high-efficiency luminescent electroluminescence device, the refractive index of the high-refractive-index matrix is 1.5-2.7.

In the high-efficiency luminous electroluminescent device, the material of the surface smooth layer is a polymer or a nanocomposite material containing inorganic nanoparticles, and the nanocomposite material is composed of nanoparticles and organic modifiers with high refractive index.

In the high-efficiency luminescent electroluminescent device, the nanoparticles are selected from aluminum oxide, antimony oxide, cadmium oxide, zirconium oxide, iron oxide, copper oxide, lead oxide, manganese oxide, tin oxide, zinc selenide, Zinc telluride, zinc sulfide, zinc oxide, cadmium sulfide, cadmium selenide, silicon oxide, titanium oxide or lead sulfide and one or more mixtures thereof.

In the high-efficiency luminescent electroluminescent device, the high-refractive-index organic modifier has a refractive index greater than 1.65.

In the high-efficiency luminescent electroluminescent device, the structure of the high-refractive organic modifier is: Y-R-X.

In the high-efficiency luminous electroluminescent device, the functional group Y is a group that can form physical or chemical bonds with inorganic nanoparticles.

In the high-efficiency luminous electroluminescence device, the functional group Y is selected from mercapto, hydroxyl, carboxylic acid, sulfonic acid, phosphoric acid and alkylsilyloxy.

In the high-efficiency luminescent electroluminescent device, the functional group X is selected from any organic functional group.

In the high-efficiency light-emitting electroluminescent device, the functional group X is a polymerizable group.

In the high-efficiency luminous electroluminescent device, the functional group X is selected from -OH, -COOH, -NH2, -NCO or double bonds.

In the high-efficiency light-emitting electroluminescent device, the functional group R has a high refractive index.

In the high-efficiency luminescent electroluminescence device, the functional group R contains sulfur or contains a conjugated group structure.

In the high-efficiency luminous electroluminescent device, the polymer is selected from polyester, polysulfone, polyurethane, polyamide or vinyl polymer.

In the described high-efficiency luminescent electroluminescent device, the polymer is selected from polyvinylcarbazole, polyvinylnaphthalene, polyphenylene sulfide, polyvinylthiophene, polyurethane containing phenylene sulfide and naphthyl , phenylene sulfide polyamide, polythioacrylate, polythiomethacrylate salt or polyacrylate 2-phenyl-2-thiophenylethyl ester.

In the high-efficiency luminescent electroluminescent device, the polymer is in a linear, branched and cross-linked structure.

In the high-efficiency luminescent electroluminescence device, the size of the scattering dispersion is 0.3-3 microns.

In the high-efficiency luminescent electroluminescent device, the difference between the scattering dispersion and the high-refractive index matrix is greater than 0.1.

In the high-efficiency luminous electroluminescent device, the difference between the scattering dispersion and the high-refractive index matrix is greater than 1.0.

In the high-efficiency luminous electroluminescent device, the scattering dispersion is selected from polymers, inorganic glasses, gases or vacuum holes.

In the high-efficiency luminous electroluminescent device, the thickness of the smooth surface layer is 0.05-5 microns.

In the high-efficiency luminous electroluminescence device, the thickness of the anti-short circuit layer is 10nm-200nm.

In the high-efficiency luminescent electroluminescence device, the surface resistivity of the anti-short circuit layer is 1×10 ⁶ ohm/square-1×10 ¹² ohm/square.

In the high-efficiency luminescent electroluminescent device, the material of the anti-short circuit layer is selected from molybdenum oxide, barium oxide, antimony oxide, bismuth oxide, rhenium oxide, tantalum oxide, tungsten oxide, niobium oxide, nickel oxide or their mixture.

In the high-efficiency luminescent electroluminescent device, the material of the anti-short circuit layer is a mixed conductive oxide and an insulating material, wherein the mixed conductive oxide includes indium oxide, gallium oxide, zinc oxide, tin oxide, Aluminum-doped zinc oxide or their mixture, and the insulating material is selected from oxides, fluorides, nitrides, sulfides or their mixtures.

In the high-efficiency luminous electroluminescent device, the material of the anti-short circuit layer is a mixture of indium tin oxide and zinc sulfide or a mixture of indium tin oxide, zinc sulfide and silicon dioxide.

In the high-efficiency luminous electroluminescence device, the material of the anti-short circuit layer is an organic material including PEDOT/PSS, polythiophene or polyaniline.

In the high-efficiency luminous electroluminescent device, the reflective electrode layer is selected from silver, copper, aluminum or their alloys.

In the high-efficiency light-emitting electroluminescent device, the LED unit is a stacked LED.

The method for preparing a high-efficiency luminescent electroluminescent device of the present invention comprises the following steps:

1) Prepare a carrier with at least one smooth surface;

2) installing the high refractive index matrix layer on the smooth surface of the carrier;

3) installing the dispersion in the matrix layer to form a light scattering layer;

4) installing a substrate on the opposite side of the carrier provided, and bonding it to the scattering layer;

5) separating the substrate with the light scattering layer from the carrier;

6) Install an organic light emitting diode unit on the light scattering layer.

Described method comprises the following steps:

1) Prepare a carrier with at least one smooth surface;

2) installing the high refractive index matrix layer on the smooth surface of the carrier;

3) installing the dispersion in the matrix layer to form a scattering layer;

4) Provide a substrate on the opposite side of the carrier and bond it to the scattering layer;

5) separating the substrate with the light scattering layer from the carrier;

6) Add a smooth layer on top of the light scattering layer;

7) Install an OLED unit on the smooth layer.

Described method comprises the following steps:

1) Installing the high refractive index matrix layer and the dispersion mixture directly on the matrix;

2) Install an organic light emitting diode unit on the light scattering layer.

Described method comprises the following steps:

1) Installing the high refractive index matrix layer and the dispersion mixture directly on the matrix to form a light scattering layer;

2) add a smooth layer on the light scattering layer;

3) Install an OLED unit on the smooth layer.

In the said method, the formation method of the light scattering layer is as follows: firstly, the scattering dispersion is mixed in through the method of solution blending, and coated on the transparent substrate to form.

In the above method, the light scattering layer is formed by first forming a film with holes by mechanical embossing, and then bonding it on a transparent substrate.

In the above method, the formation method of the light scattering layer is as follows: firstly, the condensation/evaporation of water particles self-assembles to form holes during film formation, and then adheres to the transparent substrate to form.

In the method, the step of adding a smooth surface layer is also included.

In the method, the step of adding an anti-short circuit layer is also included.

In the method, the carrier is tempered glass or plastic.

In the method, the carrier is a soft board.

In the method, the carrier is in the form of a roll and cut into sheets after each step.

In the above method, the method for preparing an electroluminescent device further includes pretreating the carrier with a release agent before installing the scattering layer on the carrier.

When light is emitted from the light-emitting layer of the light-emitting unit, it passes through the transparent electrode layer, hits the scattering layer, and is scattered. Part of the organic light and substrate light can be scattered at an angle smaller than the critical angle, and can enter the air. Since the refractive index of the smooth surface layer is higher than that of the light-emitting layer, originally air light, base light and organic light can all pass through the scattering layer and can be effectively scattered. The proximity of the scattering particles to the transparent electrode layer also ensures good light penetration and good scattering efficiency. The light output efficiency of the present invention can be further improved by selecting a protective layer with a light refractive index less than or equal to the substrate, so that the scattered light enters the protective layer from the scattering layer and less internal reflection occurs at the interface of the protective layer/substrate or substrate/air loss.

The smooth layer has a high refractive index, and its refractive index is greater than or equal to the refractive index of the light-emitting layer, which can promote the combination of light to the scattering layer and improve the light extraction efficiency. The anti-short circuit layer has a high refractive index, and can reduce the damage of the short circuit to the light emitting device.

The stacked OLED unit has a plurality of light-emitting elements, and each light-emitting element has at least one light-emitting layer. When electricity is passed between the transparent electrode layer and the reflective electrode layer, the current passes through multiple light-emitting layers, so that all light-emitting layers emit light, thereby increasing the light-emitting efficiency.

Technical effects of the present invention: 1) Improve light output efficiency; 2) Reduce production cost.

Description of drawings

Fig. 1 is the sectional view of the OLED of the embodiment 1 of the present invention;

Fig. 2 is the sectional view of the OLED of the embodiment 2 of the present invention;

Fig. 3 is the sectional view of the OLED of the embodiment 3 of the present invention;

Fig. 4 is the sectional view of the OLED of the embodiment 4 of the present invention;

5 is a cross-sectional view of an OLED according to Embodiment 5 of the present invention;

Among them, 10 is a substrate, 14 is a light scattering layer, 20 is a reflective electrode layer, 30 is a smooth surface layer, 40 is a transparent electrode layer, 50 is an anti-short circuit layer, 60 and 60a are light-emitting elements, and 70 is a connecting unit.

Detailed ways

Example 1

As shown in FIG. 1 , the high-efficiency luminescent electroluminescent device of this embodiment includes a transparent substrate 10, a light-enhancing structure, and an organic light-emitting diode unit. The organic light-emitting diode unit includes a transparent electrode layer 40, a light-emitting element 60, a reflective electrode layer 20 and an anti- The short circuit layer 50 , the light enhancing structure includes the light scattering layer 14 and the surface smoothing layer 30 .

Example 2

As shown in Figure 2, the high-efficiency electroluminescent device of this embodiment includes a transparent substrate 10, a light-enhancing structure, and an organic light-emitting diode unit. The organic light-emitting diode unit includes a transparent electrode layer 40, a light-emitting element 60, and a reflective electrode layer 20. The structure includes a light scattering layer 14 .

Example 3

As shown in FIG. 3 , the high-efficiency luminescent electroluminescent device of this embodiment includes a transparent substrate 10, a light-enhancing structure, and an organic light-emitting diode unit. The organic light-emitting diode unit includes a transparent electrode layer 40, a light-emitting element 60, a reflective electrode layer 20 and an anti- The short circuit layer 50 , the light enhancing structure includes the light scattering layer 14 .

Example 4

As shown in FIG. 4, the high-efficiency luminescent electroluminescent device of this embodiment includes a transparent substrate 10, a light-enhancing structure, and an organic light-emitting diode unit. The organic light-emitting diode unit includes a transparent electrode layer 40, a light-emitting element 60, and a reflective electrode layer 20. The light enhancing structure includes a light scattering layer 14 and a smooth surface layer 30 .

Example 5

As shown in FIG. 5 , the high-efficiency luminescent electroluminescent device of this embodiment includes a transparent substrate 10, a light-enhancing structure, and an organic light-emitting diode unit. The organic light-emitting diode unit includes a transparent electrode layer 40, light-emitting elements 60, 60a, a connecting unit 70, The reflective electrode layer 20 and the anti-short circuit layer 50 , the light enhancing structure includes the light scattering layer 14 and the surface smoothing layer 30 .

The connection unit 70 facilitates electron injection into the electron transport layer and hole injection into the hole transport layer of two adjacent OLED units. Preferably, the connecting unit is transparent and connected in series on the OLED.

Example 6 Preparation of organic modified body of long-chain stabilizer with high refractive index

first step

2,2'-Diethylene dimercaptosulfide (50g, 0,32mol) was dissolved in 200ml of ethanol, and nitrogen gas was bubbled to exhaust the oxygen in the solution. A solution of 20 g (0.29 mol) of sodium ethoxide in ethanol was added. At room temperature, 30 g (0.28 mol) of bromoethane was added dropwise. Keep at room temperature for 20 hours. The generated sodium bromide was removed by filtration, extracted with ether/water system, washed, and finally distilled under reduced pressure to obtain the compound diethylenedithiol monoethyl sulfide, 30 g (yield 51%). NMR hydrogen spectrum (1.3ppm, t, 3H; 2.5ppm, q, 2H; 2.8-2.9, m, 8H)

second step

Diethylenedithiol monoethylsulfide (25 g, 0.14 mol) was dissolved in 200 ml of anhydrous tetrahydrofuran (THF), and 3-isocyanatopropyltrimethoxysilane (40 g, 0.195 mol) was added. The reaction was refluxed under nitrogen for 6 hours. The solvent and unreacted compounds were distilled off in vacuo to obtain a crude product. Extraction with a hexane/ether mixture gave the final product. According to the NMR spectrum, the main component is the product with a purity of 85-90% (0.5ppm, m, 2H; 1.25ppm, t, 3H; 1.5ppm, t, 2H; 2.5ppm, q, 2H; 2.8ppm, t, 4H ;3.1-3.4ppm, m, 15H)

Example 7 Preparation of organic modified body of long-chain stabilizer with high refractive index

first step

2,2'-Diethylene dimercaptosulfide (46g, 0,30mol) was dissolved in 200ml of ethanol, and the oxygen in the solution was exhausted by bubbling nitrogen gas. A solution of 21 g (0.30 mol) of sodium ethoxide in ethanol was added. At room temperature, 40 g (0.5 mol) of 2-chloroethanol was added dropwise. Reflux for 4 hours under nitrogen protection. The generated sodium chloride was removed by filtration, extracted with ether/water system, washed, and finally distilled under reduced pressure to obtain the product, 42 g (yield 70%). NMR hydrogen spectrum (3.4ppm, t, 2H; 2.7-2.9ppm, m, 10H)

second step

Using the product in the previous step as a reactant, the obtained a-mercapto-w-hydroxyl compound (25 g, 0, 126 mol) was dissolved in 200 ml of ethanol, and the oxygen in the solution was exhausted by bubbling nitrogen gas. A solution of 8.2 g (0.12 mol) of sodium ethoxide in ethanol was added. At room temperature, 20 g (0.13 mol) of 4-chloromethylstyrene and a small amount of polymerization inhibitor were added dropwise. Reflux for 2 hours under nitrogen protection. The generated sodium chloride was removed by filtration, extracted with ether/water system, washed, and finally put on a silica gel column and rinsed with hexane/ethyl acetate mixture to obtain the compound, 24g (58% yield). NMR hydrogen spectrum (2.5-2.9ppm, m, 10H; 3.4ppm, t, 2H; 3.7ppm, s, 2H; 5.2ppm, d, 1H; 5.6ppm, d, 1H; 6.5ppm, m, 1H; 7.2ppm , d, 2H; 7.6ppm, d, 2H)

third step

Use the product in the previous step as a reactant to obtain the corresponding long-chain stabilizer containing double bonds. According to NMR results, the purity is 85%. Major NMR peaks (0.5ppm, Si- CH2- ; 1.5ppm, CH2- CH2 -CH2; 5.2-6.5ppm, double bond; 7.2-7.6ppm, benzene ring)

Example 8 Preparation of Organic Modified Body of Long-chain Stabilizer with High Refractive Index

first step

2,2'-Diethylene dimercaptosulfide (50g, 0,32mol) was dissolved in 200ml of ethanol, and nitrogen gas was bubbled to exhaust the oxygen in the solution. A solution of 20 g (0.29 mol) of sodium ethoxide in ethanol was added. At room temperature, 48 g (0.28 mol) of benzyl bromide was added dropwise. Keep at room temperature for 20 hours. The generated sodium bromide was removed by filtration, extracted with ether/water system, washed, and finally distilled under reduced pressure to obtain the compound diethylenedithiol monobenzyl sulfide, 52 g (yield 71%). Proton NMR spectrum (2.7-2.9 ppm, m, 8H; 3.7 ppm, s, 2H; 7.2-7.4 ppm, m, 5H).

second step

According to the same method as in Example 6, using the product in the first step as a reactant, the corresponding long-chain stabilizer was obtained. According to NMR results, the purity is 86%.

Example 9 Preparation of organic modified body of long-chain stabilizer with high refractive index

first step

2,2'-Diethylene dimercaptosulfide (50g, 0,32mol) was dissolved in 200ml of ethanol, and nitrogen gas was bubbled to exhaust the oxygen in the solution. A solution of 20 g (0.29 mol) of sodium ethoxide in ethanol was added. At room temperature, 66 g (0.30 mol) of 1-bromomethylnaphthalene was added dropwise. Keep at room temperature for 20 hours. Remove the sodium bromide that generates by filtration, extract and wash with ether/water system, and finally go up the silica gel column and obtain compound with hexane/ethyl acetate mixture rinse, diethylene dithiol mononaphthalene methyl sulfide, 54g (yield 61%). NMR hydrogen spectrum (2.7-2.9ppm, m, 8H; 4.1ppm, s, 2H; 7.0-8.2ppm, m, 7H)

second step

According to the same method as in Example 6, using the product in the first step as a reactant, the corresponding long-chain stabilizer was obtained. According to NMR results, the purity is 80%.

Example 10 Preparation of Organic Modified Body of Long Chain Stabilizer with High Refractive Index

first step

2,2'-Diethylene dimercaptosulfide (50g, 0,32mol) was dissolved in 200ml of ethanol, and nitrogen gas was bubbled to exhaust the oxygen in the solution. A solution of 20 g (0.29 mol) of sodium ethoxide in ethanol was added. At room temperature, 64 g (0.3 mol) of 2-chloromethyldithiophene was added dropwise. Keep at room temperature for 20 hours. Remove the sodium chloride generated by filtration, extract and wash with ether/water system, and finally go to the silica gel column and wash with hexane/ethyl acetate mixture to obtain the compound, diethylenedithiol mono-dithiophene methyl sulfide, 48g (produced rate of 48%). NMR hydrogen spectrum (2.7-2.9ppm, m, 8H; 3.7ppm, s, 2H; 6.8ppm, d, 1H; 7.2ppm, t, 1H; 7.5-7.7ppm, m, 3H)

second step

According to the same method as in Example 6, using the product in the first step as a reactant, the corresponding long-chain stabilizer was obtained. According to NMR results, the purity is 90%.

Example 11 Preparation of Organic Modified Body of Long Chain Stabilizer with High Refractive Index

first step

2,2'-Diethylene dimercaptosulfide (50g, 0,32mol) was dissolved in 200ml of ethanol, and nitrogen gas was bubbled to exhaust the oxygen in the solution. A solution of 20 g (0.29 mol) of sodium ethoxide in ethanol was added. At 0°C, 27 g (0.3 mol) of acrylic acid chloride was added dropwise. Keep at room temperature for 20 hours. Add a small amount of polymerization inhibitor, remove the generated sodium chloride by filtration, extract with ether/water system, wash, and finally distill under reduced pressure to obtain compound diethylenedithiol monoacrylate thioester, 45g (yield: 72%). NMR hydrogen spectrum (2.7ppm, t, 2H; 2.9ppm, t, 2H; 3.1ppm, t, 2H; 3.3ppm, t, 2H; 5.9ppm, d, 1H; 6.2ppm, d, 1H; 6.4ppm, m , 1H)

second step

According to the same method as in Example 6, using the product in the first step as a reactant, the corresponding long-chain stabilizer was obtained. According to NMR results, the purity is 84%.

Example 12 Preparation of surface-modified nanocomposites

1. Synthesis of titanium oxide nanoparticles

Mix 100g of butyl titanate, 17.1g of n-hexanoic acid and 9.26g of deionized water, place in a stirrable autoclave, bubble for 10min to remove excess air in the reactor, heat to 250°C, at this temperature Maintain for 5h. After the reaction kettle was cooled to room temperature, and the pressure inside and outside the kettle was equalized, the reaction liquid was taken out, centrifuged, and the obtained solid was washed with n-hexane for 3 times, and then placed in a refrigerator to freeze for later use.

2. Titanium dioxide surface modification

Take 2.41 g of wet titanium dioxide solids and disperse them in 40 ml of xylene, add 1.0 g of the sulfur-containing long-chain siloxane prepared in Example 6 and 0.3 g of the unsaturated sulfur-containing long-chain siloxane compound prepared in Example 7, and react at 80°C for 2 hours , centrifuged, washed with n-hexane and then centrifuged to obtain a solid, which was dispersed in xylene and set aside.

Example 13 Preparation of surface-modified nanocomposites

1. Synthesis of titanium oxide nanoparticles

Mix 150g butyl titanate, 50ml n-butanol, 25.5g n-hexanoic acid and 14.0g deionized water, place in a stirrable autoclave, bubble for 10min to remove excess air in the reactor, and heat to 250°C , maintained at this temperature for 5h. After the reaction kettle was cooled to room temperature, the pressure inside and outside the kettle was equalized, the reaction solution was taken out, centrifuged, and the obtained solid was washed with n-hexane for 3 times, and then placed in a refrigerator to freeze for later use.

2. Titanium dioxide surface modification

Take 7.6g of wet titanium dioxide solid and disperse it in 150ml butanone, add 1.0g of the sulfur-containing long-chain siloxane prepared in Example 6 and 0.3g of the unsaturated sulfur-containing long-chain siloxane compound prepared in Example 7, and react at 68°C for 2h Finally, add 2.27g of 5% ammonia water, cool down to 45°C, and react overnight. After removing most of the solvent by distillation under reduced pressure, add n-hexane to wash, centrifuge, redisperse in n-hexane, wash and centrifuge to obtain a solid, disperse in 2-pentanone, and set aside.

Example 14 Preparation of a surface smooth layer and detection of its refractive properties

The siloxane-modified titanium dioxide of Example 13 was dispersed in 2-pentanone to prepare a dispersion with a mass concentration of 10%. Spin-coating is applied on 2cm×2cm silicon wafers and glass at a rotational speed of 1000rpm for 20 seconds, and vacuum baked at 110°C for 5h. The film thickness and refractive index were measured by a film thickness meter, see Table 1.

Table 1

Film thickness (nm) Refractive index 183.2 2.245 204.5 2.096 220.6 2.125 195.8 2.256 178.9 2.284 214.5 2.143 225.3 2.015 189.8 2.251

It can be seen from Table 1 that the obtained surface smooth layer has a high refractive index.

Example 15 Preparation of light scattering layer

The light-scattering layer includes a high-refractive-index matrix and a scattering dispersion. The high-refractive-index matrix is a nanocomposite material containing inorganic nanoparticles, which is composed of nanoparticles and high-refractive-index organic modifiers; the scattering dispersion is a material whose refractive index is different from that of the matrix. Micron-sized particles or cavities. Example 13 is an example of a high refractive index matrix. TiO2 is an example of a scattering dispersion.

first step

Add 10g TiO ₂ (Dupont R series) and 1g dispersant (Lubrizol Solsperse series) to 200g toluene solvent, put it into the grinding medium and grind it, take a sample after 19h for light scattering test, the dispersion stability of TiO2 is measured by the average The change in count rate is measured. Disperse 4.67g of the above-mentioned TiO2 suspension and 0.20g of UV glue (Gulibao UV glue) in 3.13g of toluene, take about 1mL of the mixed solution and drop it on a glass plate with a size of 50mm×50mm, and use spin coating at a speed of 3000rpm After 15 seconds of UV curing, bake at 90°C for 15 minutes, and the film thickness is about 450nm.

second step

After spin-coating 50% (wt) UV glue (Gulibao UV glue) on the film obtained in the previous step, infiltrate the scattering layer, in a vacuum environment, use UV glue to bond the substrate and carrier, after UV curing, remove as The glass of the carrier, resulting in a substrate structure on which the scattering particles are located.

Example 16 Preparation of light-enhancing structure

The siloxane-modified titanium dioxide sol in Example 12 was spin-coated on the light-scattering layer of Example 15 for 20 seconds, and the obtained sample film was vacuum-baked at 110° C. for 5 hours to obtain an OLED light-enhancing structure.

Example 17 Preparation of green light device

1nm MoO ₃ hole injection layer/40nm NPB hole transport layer/30nm phosphorescent host material EB915 and green dopant were sequentially deposited on a glass substrate with a 150nm thick ITO transparent electrode under a vacuum of ^10-5 Pa Material Ir(ppy) ₃ /40nm EK-ET604 electron transport layer/10nm BCP: LiF electron injection layer/150nm Al electrode to complete the fabrication of green light devices. The above experiment was repeated by replacing the aforementioned glass substrate with a substrate with a light-enhancing structure, and the results are shown in Table 2.

Example 18 Preparation of red light device

At a vacuum close to 10 ^-5 Pa, 1nm MoO ₃ hole injection layer/40nm NPB hole transport layer/30nm phosphorescent host material EB915 and red light-doped Miscellaneous material IrCou6/40nm EK-ET604 electron transport layer/10nm BCP: LiF electron injection layer/150nm Al electrode to complete the production of red light devices. The above experiment was repeated by replacing the aforementioned glass substrate with a substrate with a light-enhancing structure, and the results are shown in Table 2.

Example 19 Preparation of blue light device

1nm MoO ₃ hole injection layer/40nm NPB hole transport layer/30nm ^fluorescent light host material EK1 and blue light doped Miscellaneous material EK9/40nm EK-ET604 electron transport layer/10nm BCP: LiF electron injection layer/150nm Al electrode to complete the production of blue light devices. The above experiment was repeated by replacing the aforementioned glass substrate with a substrate with a light-enhancing structure, and the results are shown in Table 2.

Example 20 Preparation of white light device

In a vacuum close to 10 ^-5 Pa, a 25nm thick layer of BaSrO ₃ was sputtered on a glass substrate with a 150nm thick ITO transparent electrode as an anti-short circuit layer. Then deposit 1nm MoO ₃ hole injection layer/40nm NPB hole transport layer/30nm fluorescent light host material EK1 and blue light dopant material EK9/40nmEK-ET604 electron transport layer/10nm BCP:LiF electron injection layer/1nmMoO ₃ holes Injection layer/40nm NPB hole transport layer/30nm phosphorescent host material EB915 and green light dopant material Ir(ppy) ₃ /30nm phosphorescent host material EB915 and red light dopant material IrCou6/40nm EK-ET604 electron transport layer/10nm BCP : LiF electron injection layer/150nm Al electrode to complete the fabrication of white light devices. The above-mentioned plain glass substrate was replaced with a substrate with a light-enhancing structure, and the above experiment was repeated after sputtering a layer of 150nm ITO on the light-enhancing structure, as shown in Table 2.

Table 2

Claims (10)

1. A preparation method of an electroluminescent device, said electroluminescent device comprising a transparent substrate, a light-enhancing structure and an organic light emitting diode unit, said organic light emitting diode unit comprising a transparent electrode, at least a light emitting element having a light emitting layer and a reflective electrode layer, the light-enhancing structure includes a light-scattering layer, the light-scattering layer includes a high-refractive-index matrix and a scattering dispersion, and the high-refractive-index matrix is a nanocomposite material containing inorganic nanoparticles, composed of nano Composed of particles and organic modifiers with high refractive index; the scattering dispersion is micron-sized particles or cavities whose refractive index is different from that of the matrix, It is characterized in that the preparation method comprises the following steps: 1) Prepare a carrier with at least one smooth surface; 2) Install the high refractive index matrix layer on the smooth surface of the carrier; 3) Install the dispersion in the matrix layer to form a light scattering layer; 4) Install a substrate on the opposite side of the provided carrier, bonded to the scattering layer; 5) separating the substrate with the light scattering layer from the carrier; 6) Install an OLED unit on the light scattering layer. 2. The preparation method according to claim 1, characterized in that, the light-increasing structure also has a surface smooth layer with a high refractive index, and the preparation method comprises the following steps: 1) Prepare a carrier with at least one smooth surface; 2) Install the high refractive index matrix layer on the smooth surface of the carrier; 3) Install the dispersion in the matrix layer to form a scattering layer; 4) Install a substrate on the opposite side of the carrier and bond it to the scattering layer; 5) separating the substrate with the light scattering layer from the carrier; 6) Add a surface smoothing layer on top of the light scattering layer; 7) Install an OLED unit on the surface smooth layer. 3. The preparation method according to claim 1 or 2, characterized in that the formation method of the light scattering layer is as follows: firstly, the scattering dispersion is mixed in by solution blending and applied on a transparent substrate. 4. The preparation method according to claim 1 or 2, characterized in that the light scattering layer is formed by first forming a film with holes by mechanical embossing, and then bonding it on a transparent substrate. 5. The preparation method according to claim 1 or 2, characterized in that the formation method of the light scattering layer is as follows: first, the condensation/evaporation of water particles self-assembles to form holes during film formation, and then adheres to the transparent substrate formed on top. 6. The preparation method according to claim 1 or 2, further comprising the step of adding an anti-short circuit layer. 7. The preparation method according to claim 1 or 2, characterized in that the carrier is tempered glass or plastic. 8. The preparation method according to claim 1 or 2, characterized in that the carrier is a soft board. 9. The preparation method according to claim 1 or 2, characterized in that, said carrier is in a roll shape and cut into sheets after each step. 10. The preparation method according to claim 1 or 2, characterized in that the method for preparing the electroluminescent device further comprises pre-treating the carrier with a release agent before installing the scattering layer on the carrier.