CN110277503A - Organic light-emitting device and its preparation method - Google Patents

Abstract

The present invention relates to an organic light-emitting device, which includes a substrate, a first electrode, a light-emitting functional layer and a second electrode, and is characterized in that the organic light-emitting device further includes a mixed extraction layer, which is composed of a covering layer and a particle scattering layer, Wherein the covering layer is arranged above the first electrode and/or the second electrode, and the particle scattering layer is arranged above the covering layer; wherein the refractive index of the covering layer is higher than that of the light emitting layer in the light emitting functional layer or the multiple of the light emitting functional layer The effective refractive index of the organic material layer; the refractive index of the particle scattering layer is lower than that of the covering layer. The invention also relates to a method for manufacturing the organic light emitting device.

Description

Organic light-emitting device and its preparation method

technical field

The invention relates to an organic light-emitting device and a preparation method thereof.

Background technique

Organic light-emitting diodes (OLED: Organic Light Emission Diodes) have been used more and more in the fields of lighting and display because of their advantages such as self-luminescence, high efficiency, good color rendering performance, and flexible preparation. The above advantages make OLED have a very wide application prospect. At present, OLED research has received extensive attention and research enthusiasm.

At present, most OLED light-emitting devices have a multi-layer sandwich structure, which includes electrode material film layers and organic functional material layers sandwiched between different electrode film layers; various functional materials are superimposed on each other according to the application to form an OLED light-emitting device. As a current device, when a voltage is applied to the electrodes at both ends of the OLED light-emitting device, and when the electric field acts on the positive and negative charges in the organic layer functional material film layer, the positive and negative charges recombine in the light-emitting layer, that is, OLED electroluminescence is generated. At present, OLED technology has been applied in flat lighting, smart phones, tablet computers and other fields, and will further expand to large-size applications such as TVs. However, compared with actual product application requirements, the luminous efficiency and service life of OLED devices And other performance also need to be further improved and perfected.

Research on improving the performance of OLED light-emitting devices includes: reducing the driving voltage of the device, improving the luminous efficiency of the device, and increasing the service life of the device. In order to continuously improve the performance of OLED devices, not only design innovations in OLED-related materials are required, but also continuous research and innovation on the light extraction enhancement structure of OLED light-emitting devices is required to obtain OLED light-emitting devices with high external quantum efficiency performance. light extraction structure.

For the improvement of the luminous efficiency of OLED devices, both internal and external factors of the device need to be considered, and the internal structure of the device has a decisive influence on the light extraction efficiency. The main problems of current OLED devices are low light extraction efficiency and large energy loss. Due to the surface plasmon effect, waveguide mode, and substrate mode caused by the internal structure and material properties of OLED devices, photons are consumed in non-radiative forms such as heat, which makes it impossible to achieve high-efficiency light extraction. Through the introduction of the hybrid extraction layer, the energy lost due to the surface plasmon effect and waveguide mode inside the device can be extracted again in the form of photons without affecting the flatness of the internal structure of the device. The specific principle is as follows: first, the photons in the organic light-emitting device are extracted through the covering layer located on the electrode, and then the extracted light is scattered and enhanced through the particle scattering layer, which increases the incident range of light and reduces the probability of total internal reflection, significantly Improve the external quantum efficiency of the device.

Therefore, in view of the current industrial application requirements of OLED devices, as well as the requirements of different functional film layers and photoelectric characteristics of OLED devices, light extraction materials with excellent performance, simple preparation process and low cost are selected to construct the internal structure of OLED light-emitting devices. The light extraction efficiency of a light emitting device has an important influence.

Contents of the invention

The invention provides an organic light-emitting device, which includes a substrate, a first electrode, a light-emitting functional layer, and a second electrode, and is characterized in that the organic light-emitting device also includes a mixed extraction layer, which is composed of a covering layer and a particle scattering layer , wherein the covering layer is disposed above the first electrode and/or the second electrode, and the particle scattering layer is disposed above the covering layer;

The refractive index of the covering layer is higher than the refractive index of the light emitting layer in the light emitting functional layer or the effective refractive index of the multilayer organic material layers in the light emitting functional layer; the refractive index of the particle scattering layer is lower than that of the covering layer.

The present invention also relates to a method for manufacturing the above-mentioned organic light-emitting device, characterized in that the method comprises:

depositing the cover layer over the first electrode and/or the second electrode of the organic light-emitting member including the first electrode, the light-emitting functional layer, and the second electrode by vacuum thermal evaporation; and

After the scattering particle material and the curing material are mixed in proportion, they are deposited on the covering layer by scrape coating or spin coating, and cured by photothermal method to form the particle scattering layer.

The cover layer mentioned in the present invention has a higher refractive index than the refractive index of the light-emitting layer of the OLED device or the effective refractive index of the multi-layer organic material layer in the light-emitting functional layer, and its range is between 2.0-2.6, covering The high refractive index of the layer can initially effectively extract most photons in the device, and reduce the light loss caused by total reflection at the interface and surface plasmon effect. The particle scattering layer consisting of the solidified layer and the particle material has a lower refractive index than the covering layer, which is in the range of 1.2-1.5. The refractive index of the covering layer is higher than the refractive index of the light-emitting layer or the effective refractive index of the multi-layer organic material layer, so light will be extracted by the covering layer. When the light extracted through the covering layer is incident on the scattering particle layer, part of the light below the critical value of the incident angle will be directly coupled out. Due to the existence of scattering particle materials, the extracted light is scattered to all directions, which increases the light output range. And it greatly reduces the return light being scattered into reflected light at various angles again, reducing the probability of secondary total reflection. As a result, a considerable portion of photons are extracted from the outside of the OLED light-emitting device, thereby achieving the purpose of improving the external quantum efficiency of the OLED device. _The mixed extraction layer involved in the present invention can also be considered theoretically as the introduction of the mixed extraction layer reduces the overall light absorption _of the device. In B (n ₁ >n ₂ ), the light absorption rate K of the medium can be expressed by the following formula:

It can be seen from the publicity that within a specific range, when the refractive index n ₂ of the medium is smaller and n ₁ is larger, the light absorption rate of the medium will be smaller, that is, the light extraction effect will be better.

The invention enhances the light extraction efficiency by processing the mixed extraction layer on the transparent electrode of the emitting device. Through the introduction of the mixed extraction layer structure, the external quantum efficiency of the organic light-emitting device has been significantly improved, and the purpose of light extraction has been achieved.

When the device structure involved in the present invention is applied to an OLED device, through device structure optimization, high film layer stability can be maintained and the light extraction efficiency of the OLED device can be effectively improved. The structure of the invention has good application effect and industrialization prospect in OLED light-emitting devices.

Description of drawings

1 is a schematic structural view of an organic light-emitting device of the present invention;

2 is a schematic diagram of the structure of the substrate part and the first electrode disposed on the substrate of the present invention;

3 is a schematic structural view of the hole injection transport layer (which represents the hole transport layer and the hole injection layer) disposed on the first electrode of the present invention;

FIG. 4 is a schematic diagram of the structure of the light-emitting layer disposed on the hole injection transport layer according to the present invention;

5 is a schematic diagram of the structure of the electron transport injection layer disposed on the light emitting layer according to the present invention;

6 is a schematic diagram of the structure of the second electrode disposed on the electron transport injection layer (it represents the electron transport layer and the electron injection layer) according to the present invention;

Fig. 7 is the part of the mixed extraction layer arranged on the second electrode of the present invention;

Fig. 8 is a schematic structural diagram of an organic light-emitting device in which an encapsulation layer is disposed on a cover layer;

The external quantum efficiency performance data comparison figure of Fig. 9 embodiment 1 of the present invention and comparative example 1 and 2;

Description of reference numerals for each component

1 Substrate

21 Second electrode

22 First electrode

31 Hole injection transport layer

32 luminous layer

33 electron transport injection layer

41 Overlay

42 particle scattering layer

5 Package Substrate

Detailed ways

The invention provides an organic light-emitting device, which includes a substrate, a first electrode, a light-emitting functional layer, and a second electrode, and is characterized in that the organic light-emitting device also includes a mixed extraction layer, which is composed of a covering layer and a particle scattering layer , wherein the covering layer is disposed above the first electrode and/or the second electrode, and the particle scattering layer is disposed above the covering layer;

The refractive index of the covering layer is higher than the refractive index of the light emitting layer in the light emitting functional layer or the effective refractive index of the multilayer organic material layers in the light emitting functional layer; the refractive index of the particle scattering layer is lower than that of the covering layer.

In the present invention, the description of the orientation between the various components in the organic light-emitting device, such as "above", refers to the relative position between the various components. For the expression "the covering layer is disposed above the first electrode and/or the second electrode, and the particle scattering layer is disposed above the covering layer" means that if the first electrode is used as the processing substrate, the particle scattering layer, covering layer and the first electrode; if the second electrode is used as the processing substrate, the particle scattering layer, the covering layer and the second electrode are arranged sequentially from top to bottom.

In the present invention, the effective refractive index of the multilayer organic material layer in the luminescent functional layer refers to the multilayer organic layers contained in the luminescent functional layer, such as hole injection layer, hole transport layer or electron blocking layer, light emitting layer, The effective refractive index of the comprehensive simulation of the electron transport layer or the hole blocking layer and the electron injection, or the effective refractive index of the comprehensive simulation of the hole injection transport layer, the light emitting layer and the electron transport injection layer included in the light emitting functional layer. The effective refractive index is obtained by an effective refractive index method known to those skilled in the art.

In one embodiment of the present invention, the cover layer in the organic light-emitting device has a refractive index of 2.0-2.6, preferably 2.2-2.6, a thickness of 50-500 nm, preferably 50-300 nm, and a light transmittance higher than 80%; The refractive index of the particle scattering layer is 1.2-1.5, and the thickness is 10-50 μm, preferably 25-50 μm.

In one embodiment of the present invention, the particle scattering layer in the organic light-emitting device is composed of cured material and scattering particle material, wherein based on the total weight of the particle scattering layer, the scattering particles account for 10wt%-50wt% %, preferably 15wt%-35wt%, more preferably 18wt%-30wt%;

Wherein the scattering particles are a mixture of nanoparticles of different particle sizes, which are uniformly distributed in the solidified material, and the scattering particles are a mixture of nanoparticles of different particle sizes ranging from 10nm to 3000nm, preferably 100nm to 1000nm, Wherein the particles of 400-800nm account for more than 50wt%, preferably more than 60wt%, more preferably more than 70wt%.

In one embodiment of the present invention, for a red light-emitting device, based on the total weight of the particle scattering layer, the scattering particles are 15wt%-20wt%, and the particle size range of the scattering particles is between 100nm and 1000nm, preferably 300nm to 1000nm, and among the scattering particles, particles with a particle size in the range of 600-800nm, preferably 620-750nm account for more than 50wt%, preferably more than 60wt%, more preferably more than 70wt%;

In one embodiment of the present invention, for the green light-emitting device, based on the total weight of the particle scattering layer, the scattering particles account for 20wt%-25wt%, and the particle size range of the scattering particles is between 100nm and 1000nm, preferably 200nm to 900nm, and among the scattering particles, particles with a particle size in the range of 500-570nm, preferably 500-550nm account for more than 50wt%, preferably more than 60wt%, more preferably more than 70wt%;

In one embodiment of the present invention, for a blue light-emitting device, based on the total weight of the particle scattering layer, the scattering particles account for 25wt%-30wt%, and the particle size range of the scattering particles is between 100nm and 1000nm, preferably between 100nm and 100nm. 800nm, and among the scattering particles, particles with a particle size in the range of 400-530nm, preferably 430-490nm account for more than 50wt%, preferably more than 60wt%, more preferably more than 70wt%.

In one embodiment of the present invention, the curable material in the organic light-emitting device is a light-curable or heat-curable easy-to-form high-transmittance material; its light transmittance is above 80%, preferably above 85% . The curing material is generally a plastic polymer material, for example selected from polyethylene resin, epoxy resin, or polyacrylic resin.

In one embodiment of the present invention, the materials of the scattering particles may be the same or different, such as TiO ₂ , SiO ₂ , LiF or ceramics, or any mixture thereof.

In one embodiment of the present invention, an encapsulation substrate is provided on the hybrid extraction layer in the organic light emitting device as an encapsulation layer.

In one embodiment of the present invention, the light-emitting functional layer part includes: a hole injection layer, a hole transport layer or an electron blocking layer, a light emitting layer, an electron transport layer or a hole blocking layer, and an electron injection layer. In another embodiment of the present invention, the light emitting functional layer part includes: a hole injection transport layer, a light emitting layer and an electron transport injection layer. Each layer of the light-emitting functional layer part is selected from corresponding functional layers conventionally used in the art, without any limitation.

The material of the light-emitting layer is a material capable of emitting visible light by receiving holes and electrons from the hole transport layer and the electron transport layer respectively, and combining the received holes and electrons, preferably having high fluorescence and phosphorescence materials with quantum efficiency. According to its luminescent color, luminescent materials are divided into blue, green and red luminescent materials, and in order to achieve more natural colors, they are further divided into yellow and orange luminescent materials. Specific examples thereof include metal complexes of hydroxyquinoline derivatives, various metal complexes, anthracene derivatives, bisstyrenebenzene derivatives, pyrene derivatives, oxazole derivatives, and poly(p-styrene) derivatives, etc. , but not limited to this. In addition, the light emitting layer may contain a host material and a guest material. As the host material and the guest material of the light-emitting layer of the organic electroluminescent device of the present invention, all known light-emitting layer materials for organic electroluminescent devices in the prior art can be used, and the host material can be, for example, thiazole derivatives, benzene and imidazole derivatives, polydialkylfluorene derivatives or 4,4'-bis(9-carbazolyl)biphenyl (CBP); the guest material can be, for example, quinacridone, coumarin, rubyne alkenes, perylene and its derivatives, benzopyran derivatives, rhodamine derivatives or aminostyrene derivatives.

In addition, in order to improve fluorescent or phosphorescent properties, the luminescent material may also include phosphorescent or fluorescent materials. Specific examples of the phosphorescent material include phosphorescent materials of metal complexes of iridium, platinum, and the like. For example, green phosphorescent materials such as Ir(ppy) ₃ [fac-tris(2-phenylpyridine)iridium], blue phosphorescent materials such as FIrpic and FIr6, and red phosphorescent materials such as Btp2Ir(acac) can be used. As fluorescent materials, those known in the art can be used.

In addition, in addition to the fluorescent or phosphorescent host-guest materials used above, non-host-guest doping system materials known in the art for the light-emitting layer in organic electroluminescent devices, thermally activated delayed fluorescence (TADF ) functional host-guest materials, and the combination of TADF functional materials and the above-mentioned fluorescent and phosphorescent materials.

In the light-emitting layer of the present invention, the ratio of the host material to the guest material used is 99:1-70:30, based on mass.

The thickness of the light-emitting layer of the present invention may be 5-60 nm.

In one embodiment of the present invention, the light-emitting layer is a single-layer light-emitting layer or a host-guest structure, wherein the host-guest structure is any structure conventionally selected in the field, preferably double host + guest, single host + guest, host + TADF assisted doping + guest.

In the present invention, the electron transport region may include a hole blocking layer, an electron transport layer, and an electron injection layer, but is not limited thereto.

The hole blocking layer is a layer that blocks holes injected from the anode through the light emitting layer and enters the cathode, thereby prolonging the lifetime of the device and improving the performance of the device. The hole blocking layer of the present invention may be disposed on the light emitting layer. As the hole-blocking layer material of the organic electroluminescent device of the present invention, compounds with hole-blocking effects known in the prior art can be used, for example, phenanthroline derivatives such as bathocuproine (called BCP), aluminum (III) Metal complexes of hydroxyquinoline derivatives such as bis(2-methyl-8-quinoline)-4-phenylphenolate (BAlq), various rare earth complexes, oxazole derivatives, Triazole derivatives, triazine derivatives, etc. The hole blocking layer of the present invention may have a thickness of 2-200 nm.

The electron transport layer material is a material that easily receives electrons from the cathode and transfers the received electrons to the light emitting layer. Materials with high electron mobility are preferred. As the electron transport layer of the organic electroluminescent device of the present invention, the electron transport layer materials known in the prior art for organic electroluminescent devices can be used, for example, tris (8-hydroxyquinoline) aluminum (Alq ₃ ) , 2-methyl-8-hydroxyquinoline p-hydroxybiphenyl aluminum (BAlq) metal complexes of hydroxyquinoline derivatives, various metal complexes, triazole derivatives, triazine derivatives , oxadiazole derivatives, thiadiazole derivatives, carbodiimide derivatives, quinoxaline derivatives, phenanthroline derivatives, silicon-based compound derivatives, etc. The electron transport layer of the present invention may have a thickness of 10-80 nm.

The electron injection layer material is generally a material preferably having a low work function so that electrons are easily injected into the organic functional material layer. As the electron injection layer material of the organic electroluminescent device of the present invention, the electron injection layer materials known in the prior art for organic electroluminescent devices can be used, for example, alkali metals such as lithium fluoride (LiF) and cesium fluoride Salt, alkaline earth metal salts such as magnesium fluoride, metal oxides such as alumina, etc. The thickness of the electron injection layer of the present invention may be 0.1-5 nm.

In the present invention, the hole transport region includes a hole transport layer, an electron blocking layer and a hole injection layer, but is not limited thereto.

Generally, an organic material having a p-type property, which is easily oxidized and electrochemically stable when it is oxidized, is mainly used as a hole injection material or a hole transport material. Meanwhile, organic materials having n-type properties, which are easily reduced and electrochemically stable when reduced, are used as electron injection materials or electron transport materials. As the light-emitting layer material, a material having both p-type properties and n-type properties is preferable, it is stable when it is oxidized and reduced, and it is also preferable to have high luminescence for converting excitons into light when excitons are formed efficient material.

The material of the hole injection layer is generally a material preferably having a high work function so that holes are easily injected into the organic material layer. Specific examples of the material of the hole injection layer include, but are not limited to, copper phthalocyanine, N,N'-diphenyl-N,N'-bis-[4-(phenyl-m-toluene-amino)-phenyl ]-biphenyl-4,4'-diamine (DNTPD), 4,4',4"-tris(3-methylphenylphenylamino)triphenylamine (m-MTDATA), 4,4'4" -Tri(N,N-diphenylamino)triphenylamine (TDATA), 4,4',4"-tri{N,-(2-naphthyl)-N-phenylamino}-triphenylamine (2TNATA) , poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS), polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA), polyaniline/ Camphorsulfonic acid (PANI/CSA) or (polyaniline)/poly(4-styrenesulfonate) (PANI/PSS). The thickness of the hole injection layer of the present invention can be 5-100 nm.

The material of the hole transport layer is preferably a material with high hole mobility, which enables the transfer of holes from the anode or the hole injection layer to the light emitting layer. Specific examples of materials for the hole transport layer include, but are not limited to: carbazole-based derivatives such as N-phenylcarbazole or polyvinylcarbazole; fluorene-based derivatives; triphenylamine-based derivatives such as N ,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1-biphenyl]-4,4'-diamine (TPD) and 4,4',4" -Tris(N-carbazolyl)triphenylamine (TCTA), N,N'-bis(1-naphthyl)-N,N'-diphenylbenzidine (NPB), 4,4'-cyclohexylene Bis[N,N-bis(4-methylphenyl)aniline] (TAPC).The thickness of the hole transport layer of the present invention can be 5-200nm.

The hole injection layer and/or the hole transport layer may also contain a charge generation material for improving conductivity. The charge generating material may be a p-dopant. Non-limiting examples of P-dopants are, for example, quinone derivatives such as tetracyanoquinodimethane (TCNQ) and 2,3,5,6-tetrafluoro-tetracyano-1,4- Benzoquinodimethane (F4-TCNQ); hexaazatriphenylene derivatives such as 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaaza Triphenylene (HAT-CN); cyclopropane derivatives such as 4,4',4"-((1E,1'E,1"E)-cyclopropane-1,2,3-trimethylenetri(cyano) carbamide)) tris(2,3,5,6-tetrafluorobenzyl); metal oxides such as tungsten oxide and molybdenum oxide.

In one embodiment of the present invention, the substrate of the organic light emitting device is a flexible substrate or a rigid substrate, a transparent substrate or an opaque substrate. As the substrate of the organic electroluminescent device of the present invention, any substrate used in typical organic light emitting devices can be selected, not limited to flexible substrates and rigid substrates. It can be a glass or transparent plastic substrate; it can also be an opaque material such as silicon or stainless steel; it can also be a flexible PI film. Different substrates have different properties of mechanical strength, thermal stability, transparency, surface smoothness, and water resistance. According to different properties, they can be used in different directions.

The present invention also provides a method for manufacturing the organic light-emitting device, characterized in that the method comprises:

depositing the cover layer over the first electrode and/or the second electrode of the organic light-emitting member including the first electrode, the light-emitting functional layer, and the second electrode by vacuum thermal evaporation; and

The scattering particle material and the curing material are mixed in proportion, deposited on the cover layer by scraping or spin coating, and cured by photothermal method to form the particle scattering layer.

In one embodiment of the present invention, an encapsulation substrate is formed on the particle scattering layer.

In a preferred embodiment of the present invention, the layer of scattering particles can also encapsulate the organic light emitting device at the same time.

Preferably, the covering layer is located above the first electrode and/or the second electrode, has a higher refractive index than the light-emitting layer, and has good light transmittance, and can be deposited by vacuum thermal evaporation.

Scattering particles of different particle sizes are all distributed in the cured material, which can enhance the scattering effect on light of different wavelengths of the organic light-emitting device, avoiding the effect of particles with a single particle size only on light scattering enhancement of a single wavelength.

The particle scattering layer is composed of curing material and scattering particle material, wherein the curing material can be easily moldable material such as polyethylene, light curing material such as polyepoxy resin, heat curing material such as polyacrylic resin, and the like. The particle scattering layer has a lower refractive index than the covering layer, for example in the range of 1.2-1.5.

For the top emission structure, the processing and construction steps of the mixed extraction layer structure are as follows: after the construction of the second transparent electrode layer as the cathode is completed, the covering layer is firstly deposited and constructed on the second electrode by vacuum thermal evaporation, and then scraped or spin-coated. The method of coating and photothermal curing is used to process and construct the particle scattering layer.

The organic light-emitting device of the present invention can be applied to lighting equipment, which introduces a mixed extraction layer structure composed of a covering layer and a particle scattering layer above the electrode, through the refraction and scattering of the photons radiated by the organic light-emitting device through the mixed extraction layer, to achieve light emission. The enhanced effect is extracted, and the external quantum efficiency of the organic light-emitting device is significantly improved.

The basic structure of an organic light emitting device is, for example, electrode/hole injection transport layer/light emitting layer/electron transport injection layer/electrode. The structure type of the organic light emitting device is not limited to structures such as a top emission structure, a bottom emission structure, or a double side emission structure. The present invention enhances the efficiency of light extraction by processing a multi-layer light extraction layer on the transparent electrode of the emitting device, for example, processing a multi-layer light extraction layer on the top transparent electrode of the top-emitting device to enhance the efficiency of light extraction or A method of processing a multi-layer light extraction layer on the bottom transparent electrode of a bottom-emitting device to enhance the efficiency of light extraction, or for a double-sided emission structure, processing a multi-layer light extraction layer on the top transparent electrode or bottom transparent electrode at the same time.

In the present invention, at least one of the first electrode and the second electrode is a transparent electrode, and the mixed extraction layer is arranged on the side of the transparent electrode. Both the first electrode and the second electrode may be transparent electrodes, and a mixed extraction layer may be provided on both the first electrode and the second electrode. A hybrid extraction layer structure consisting of a covering layer and a particle scattering layer is introduced above the electrode. Through the refraction and scattering of the radiated photons of the organic light-emitting device by the hybrid extraction layer, the effect of enhancing light extraction is achieved, and the external quantum of the organic light-emitting device is significantly improved. efficiency.

A first electrode is formed on the substrate, and the first electrode and the second electrode may face each other. The first electrode may be an anode. The first electrode may be a transmissive electrode, a semi-transmissive electrode, or a reflective electrode. When the first electrode is a transmissive electrode, the first electrode can be formed using a transparent metal oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO) or indium tin zinc oxide ( ITZO) and so on. When the first electrode is a semi-transmissive electrode or a reflective electrode, the first electrode may include Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr or a metal mixture. The first electrode is preferably a non-transparent and reflective metal electrode; if the first electrode is indium tin oxide, it is generally a finished patterned structure, which can also be formed by sputtering. The above-mentioned first electrode can be formed by methods such as sputtering, ion plating, vacuum evaporation, spin coating, electron beam evaporation or chemical vapor deposition (CVD), preferably by sputtering.

The second electrode can be a cathode, which is generally a transparent material, such as a mixed MgAg, AlAg metal electrode, or other conductive materials with high transmittance.

In one embodiment of the present invention, the first electrode layer serving as the anode is formed on the substrate, and the substrate can be made of a transparent material or a non-transparent material. The substrate can be selected from any material conventionally used in the art without limitation, such as glass or plastic.

In one embodiment of the present invention, the first electrode is a non-transparent metal electrode, and the second electrode is a transparent electrode. Above the first electrode, a hole injection transport layer portion is constructed by thermal evaporation deposition. The part of the light-emitting layer is constructed by thermal evaporation deposition on the hole injection transport layer. The part of the electron transport and injection layer is constructed by thermal evaporation deposition on the light emitting layer. A second electrode portion is constructed over the electron transport injection layer. Constructing a mixed extraction layer above the second electrode, depositing a covering layer on the first electrode and/or the second electrode of the organic light-emitting member comprising the first electrode, the light-emitting functional layer and the second electrode by vacuum thermal evaporation; And the scattering particle material and the curing material are mixed in proportion, deposited on the cover layer by scrape coating or spin coating, and cured by photothermal method to form the particle scattering layer.

Example

The implementation of the present invention is described below through specific specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes, and various modifications or changes can be made to the details in this specification based on different viewpoints and applications without departing from the spirit of the present invention.

The specific implementation process of the invention of the present application will be decomposed and described in detail below in combination with the description and the accompanying drawings. It should be noted that the same or similar reference numerals represent the same or similar elements or elements with similar functions throughout. The embodiments described below with reference to the accompanying drawings are examples only for describing the present invention, and should not be construed as limitations on the application of the present invention.

Referring to Fig. 1, the present invention provides an organic light-emitting device with a top emission structure, including a substrate 1, an electrode part 2, a functional layer part 3, a mixed extraction layer part 4 and a packaging substrate 5; wherein the electrode part includes a first electrode 21 and In the second electrode 22 , the functional layer part includes a hole injection transport layer 31 , the light emitting layer 32 and the electron transport injection layer 33 , and the mixed extraction layer part includes: a covering layer 41 and a particle scattering layer 42 .

In the organic light-emitting device described in this embodiment, the emitted light and the light reflected by the non-transparent first electrode are initially extracted by the covering layer 41 with a relatively high refractive index, and then scattered by the scattering particle layer 42 into The light in multiple incident angle directions reduces the probability of total reflection at the interface, so that this part of light can be extracted outside the device.

When the structure of this embodiment is used in the manufacturing process of the organic light emitting device, the thickness of the cover layer 41 is 50-500 nm, and the optional material is a material with a refractive index in the range of 2.0-2.6, such as SiN. The thickness of the corresponding covering layer can be adjusted according to actual needs and light of different wavelengths. In terms of emission wavelength, the shorter the emission wavelength, the smaller the thickness of the covering layer. For red light, for example, the required covering layer thickness is greater than that required for green light.

The cured material of the particle scattering layer 42 is selected from materials with a refractive index of 1.2-1.5, such as polyethylene resin, epoxy resin, or polyacrylic resin with a light transmittance of more than 85%.

The particles in the particle scattering layer 42 can be selected from TiO ₂ , SiO ₂ , LiF or ceramics with a particle diameter in the range of 100 nm-1000 nm.

After a certain forward voltage is applied between the first electrode 21 and the second electrode 22, the electron injection transport layer 31 loses electrons and forms holes to move to the light-emitting layer 32, and the electrons flow from the cathode to the light-emitting layer 32 through the electron transport injection layer 33 Moving, the two will recombine at the light-emitting layer 32 to form excitons, and the excitons will then generate photons in the form of radiative transitions.

Referring to FIG. 1 , specifically, the structural positions of the hole injection transport layer 31 and the electron transport injection layer 33 of the light-emitting functional layer 3 can be exchanged to form standard and inverted devices respectively.

Fig. 2 is a schematic diagram of depositing a first electrode on a substrate. It should be noted that the substrate material is not limited to transparent or non-transparent and rigid or flexible. The first electrode 21 is a non-transparent and reflective metal electrode, for example, a pure metal electrode such as gold, aluminum or silver, or the first electrode is indium tin oxide.

3 to 5 are schematic diagrams of the construction process of the light-emitting functional layer. The hole injection transport layer 31, the light-emitting layer 32, and the electron transport injection layer 33 are all deposited and formed by vacuum thermal evaporation. The light-emitting layer region 32 has a host-guest collocation structure, such as a single-host-guest structure, a double-host and doped-guest structure, and a single-host or auxiliary co-doped-guest structure.

FIG. 6 is a schematic diagram of the construction of the second electrode 22 . The second electrode is made of a transparent material, such as a mixed MgAg or AlAg metal electrode.

Fig. 7 is a schematic diagram of the structural construction of the mixed extraction layer, including a covering layer 41 and a particle scattering layer 42, wherein the particle scattering layer is formed by mixing a solidified layer and a granular material, and can be deposited and formed by vacuum steaming and scraping curing methods.

As shown in Fig. 8, the solid line represents the actual direction of light, and the dashed line represents the possible direction of light. When the light generated by the light-emitting layer inside the device is incident on the surface of the second electrode, since the refractive index of the covering layer 41 is higher than the effective refractive index of the light-emitting functional layer 3, the incident light will not be extracted by total reflection at the interface, That is to say, a part of total reflection light is generated, and the total reflection light will be scattered at the particle coating layer into scattered light with incident angles in multiple directions, and then enter the first coating layer again, thus increasing the probability of light output and reducing The probability of total reflection of the coupled light again.

The encapsulation substrate 5 is a rigid material encapsulation layer, which can be selected from commonly used encapsulation layer materials in existing encapsulation technologies, such as ceramic substrates, copper substrates or aluminum substrates.

Example 1:

As shown in Figure 1, the organic light-emitting device of the top emission structure of the present invention includes a substrate 1, an electrode part 2, a functional layer part 3, a mixed extraction layer part 4 and a package substrate 5; wherein the electrode part includes a first electrode 21 and a second electrode The two electrodes 22 , the functional layer part includes a hole injection transport layer 31 , the light emitting layer 32 and the electron transport injection layer 33 , and the mixed extraction layer part includes a covering layer 41 and a particle scattering layer 42 .

The organic light-emitting device in this embodiment is a green light-emitting device, and the light emitted by it and the light reflected by the non-transparent first electrode are initially extracted by the SiN covering layer 41 with a relatively high refractive index, and then scattered by _TiO2 The light at the particle layer 42 is scattered into multiple incident angle directions, which reduces the probability of total reflection at the interface, so that this part of light is extracted out of the device.

During the manufacturing process of the organic light emitting device, the thickness of the cover layer 41 is selected to be about 300 nm (the error is ±15 nm).

The cured material of the particle scattering layer 42 is selected from polyacrylic resins.

The particles in the particle scattering layer 42 are selected from TiO ₂ , and its particle size is in the range of 200nm-900nm, wherein, particles with a particle size of 500-570nm account for 75wt%; based on the total weight of the particle scattering layer, the scattering particles account for 24wt%. %; The thickness of the particle scattering layer is about 30 μm (with an error of ±0.6 μm).

The substrate material is a non-transparent rigid plastic plate. The first electrode 21 is a metal electrode silver which is non-transparent and has a reflective effect.

In this embodiment, the hole injection and transport layer 31 , the light emitting layer 32 , and the electron transport and injection layer 33 are all deposited and formed by vacuum thermal evaporation. The light-emitting layer 32 has a host-guest structure, the host material is a metal complex of hydroxyquinoline derivatives, and the guest material is a phosphorescent material.

The second electrode is an AlAg metal electrode made of transparent material.

The mixed extraction layer is composed of a covering layer 41 and a particle scattering layer 42, wherein the particle scattering layer is formed by mixing a solidified layer and a particle material, and can be deposited and formed by vacuum thermal evaporation and scrape coating curing.

The encapsulation substrate 5 is a rigid material encapsulation layer, which can be selected from copper substrate, which is a commonly used encapsulation layer material in encapsulation technology.

Comparative example 1:

The only difference between Comparative Example 1 and Example 1 is that a mixed extraction layer structure containing only a single-layer covering layer is used, and the comparison is mainly reflected in the external quantum efficiency. The cover layer of Comparative Example 1 is selected as SiN, a material with a relatively high refractive index.

Comparative example 2:

The only difference between Comparative Example 2 and Example 1 is that a mixed extraction layer structure containing only a single covering layer is used, and the comparison is mainly reflected in the external quantum efficiency. In comparative example 2, LiF is selected as a single-layer covering layer material with a relatively low refractive index.

Table 1 is a comparison summary table of the highest external quantum efficiency (%) performance values measured at different temperatures (° C.) in Example 1, Comparative Example 1 and Comparative Example 2, all taking green light devices as an example.

Table 1

Performance As shown in Figure 9, the external quantum efficiency value of the device of the present invention basically does not change significantly in the temperature range, and the performance of the device is stable. Devices with a hybrid extraction layer structure consisting of a capping layer and a particle scattering layer exhibit higher light extraction efficiency.

Claims (10)

1. An organic light-emitting device comprising a substrate, a first electrode, a light-emitting functional layer and a second electrode, characterized in that the organic light-emitting device also comprises a mixed extraction layer, which is composed of a cover layer and a particle scattering layer, wherein The covering layer is arranged on the first electrode and/or the second electrode, and the particle scattering layer is arranged on the covering layer; The refractive index of the covering layer is higher than the refractive index of the light emitting layer in the light emitting functional layer or the effective refractive index of the multilayer organic material layers in the light emitting functional layer; the refractive index of the particle scattering layer is lower than that of the covering layer. 2. The organic light-emitting device according to claim 1, wherein the cover layer has a refractive index of 2.0-2.6, a thickness of 50-500nm, preferably 50-300nm, and a light transmittance higher than 80%; the particles The refractive index of the scattering layer is 1.2-1.5, and the thickness is 10-50 μm, preferably 25-50 μm. 3. The organic light-emitting device according to claim 1 or 2, wherein the particle scattering layer is composed of a cured material and a scattering particle material, wherein based on the total weight of the particle scattering layer, the scattering particles account for 10wt% -50wt%; Wherein the scattering particles are a mixture of nanoparticles of different particle sizes, which are uniformly distributed in the solidified material, and the scattering particles are a mixture of nanoparticles of different particle sizes ranging from 10nm to 3000nm, preferably 100nm to 1000nm, Among them, the particles of 400-800nm account for more than 50wt%. 4. The organic light emitting device according to claim 3, wherein for a red light emitting device, based on the total weight of the particle scattering layer, the scattering particles are 15wt%-20wt%, and in the scattering particles, The particle size range is 600-800nm, preferably 620-750nm particles account for more than 50wt%, preferably more than 60wt%; For a green light-emitting device, based on the total weight of the particle scattering layer, the scattering particles account for 20wt%-25wt%, and among the scattering particles, particles with a particle diameter in the range of 500-570nm, preferably 500-550nm, account for more than 50wt%. , preferably more than 60wt%; For the blue light-emitting device, based on the total weight of the particle scattering layer, the scattering particles account for 25wt%-30wt% and among the scattering particles, the particles with a particle size range of 400-530nm, preferably 430-490nm, account for more than 50wt%, preferably More than 60wt%. 5. The organic light-emitting device according to claim 1 or 2, wherein the curable material is a light-curable or heat-curable easily moldable high transmittance material; The materials of the scattering particles can be the same or different, such as TiO ₂ , SiO ₂ , LiF or ceramics, or any mixture thereof. 6 . The organic light emitting device according to claim 4 , wherein an encapsulation layer is arranged on the mixed extraction layer. 7. The organic light emitting device according to claim 4, wherein the light emitting functional layer part comprises a hole injection layer, a hole transport layer or an electron blocking layer, a light emitting layer, an electron transport layer or a hole blocking layer, and the electron injection layer. 8. The organic light-emitting device according to claim 4, wherein the light-emitting layer is a single-layer light-emitting layer or a host-guest structure, wherein the host-guest structure can be double host+guest, single host+guest, host+TADF auxiliary Doping + guest; guest luminescent molecules can be fluorescent materials and phosphorescent materials. 9. A method for manufacturing an organic light-emitting device, characterized in that the method comprises: depositing the cover layer over the first electrode and/or the second electrode of the organic light-emitting member including the first electrode, the light-emitting functional layer, and the second electrode by vacuum thermal evaporation; and The scattering particle material and the curing material are mixed in proportion, deposited on the cover layer by scraping or spin coating, and cured by photothermal method to form the particle scattering layer. 10. The manufacturing method according to claim 9, wherein the packaging substrate is formed on the particle scattering layer.