KR102322966B1 - Organic light emitting diode display apparatus and method for fabricating the same - Google Patents

Abstract

의 화학식으로 표시되는 화합물로 이루어진 전자수송층(Electron Transfer Layer, ETL)을 포함하는 유기층, 유기층 상에 위치하는 제2전극 및 제2전극 상에 위치하고 반도체 물질로 이루어진 패시베이션층을 포함하는 유기발광표시장치 및 그 제조방법을 제공한다.The present invention is a first electrode positioned on a substrate, positioned on the first electrode, and an organic light emitting layer (Emission Layer, EL) and

An organic light emitting display device including an organic layer including an electron transport layer (ETL) made of a compound represented by the chemical formula of and a manufacturing method thereof.

Description

Organic light emitting display device and manufacturing method thereof

The present invention relates to an organic light emitting display device and a method for manufacturing the same.

In the flat panel display field, a light and low power consumption liquid crystal display device has been widely used so far, but the liquid crystal display device is a non-emissive device that cannot generate light by itself, and thus has luminance and contrast. ratio), a viewing angle, and a large area, etc. have disadvantages.

Accordingly, the development of a new flat panel display device capable of overcoming the disadvantages of the liquid crystal display device is being actively developed. One of the new flat panel display devices, an organic light emitting display device, is an emissive device that generates light by itself. Therefore, it is superior in brightness, viewing angle and contrast ratio compared to the liquid crystal display device, and since it does not require a backlight, it can be lightweight and thin, and is advantageous in terms of power consumption.

An organic light emitting display device displays an image using light emitted from an organic light emitting device connected to a thin film transistor in each pixel area, and the organic light emitting device forms a light emitting layer made of an organic material between an anode and a cathode. As a device that emits light by applying an electric field, it can be driven at a low voltage, consumes relatively little power, and is lightweight and can be manufactured on a flexible substrate.

When the organic light emitting diode display device is driven, a large amount of current can flow through the cathode, which causes deterioration of electrical properties such as deterioration. Since the efficiency of the blue light emitting device is relatively low, the reliability and reliability of the organic light emitting diode display device are reduced. There is a problem that the lifespan is reduced.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an organic light emitting display device with improved electrical characteristics and improved reliability and lifetime, and a method for manufacturing the same.

의 화학식으로 표시되는 화합물로 이루어진 전자수송층(Electron Transfer Layer, ETL)을 포함하는 유기층, 유기층 상에 위치하는 제2전극 및 제2전극 상에 위치하고 반도체 물질로 이루어진 패시베이션층을 포함한다.In order to achieve the above object, in one aspect, an organic light emitting display device according to the present invention includes a first electrode positioned on a substrate, a first electrode positioned on the first electrode, and an organic light emitting layer (EL) and

An organic layer including an electron transport layer (ETL) made of a compound represented by the formula of, a second electrode positioned on the organic layer, and a passivation layer made of a semiconductor material positioned on the second electrode.

의 화학식으로 표시되는 화합물로 이루어진 전자수송층(Electron Transfer Layer, ETL)을 포함하는 유기층을 형성하는 단계, 유기층 상에 제2전극을 형성하는 단계, 제2전극 상에 반도체 물질로 이루어진 패시베이션층을 형성하는 단계 및 열처리 단계를 포함한다.In another aspect, the method of manufacturing an organic light emitting display device according to the present invention includes the steps of: forming a first electrode on a substrate; on the first electrode, an organic light emitting layer (EL);

Forming an organic layer including an electron transport layer (ETL) made of a compound represented by the formula of, forming a second electrode on the organic layer, forming a passivation layer made of a semiconductor material on the second electrode and a heat treatment step.

The organic light emitting display device and the method for manufacturing the same according to the present invention have the effects of improving electrical characteristics and improving reliability and lifespan.

1 is a system configuration diagram of an organic light emitting display device to which embodiments are applied.
2A is a schematic structural diagram of an organic light emitting diode display according to example embodiments.
2B is a schematic cross-sectional view of an organic light emitting diode display according to an exemplary embodiment.
3 is a diagram illustrating paths of lights in an organic light emitting diode display according to example embodiments.
4 is a diagram illustrating a graph comparing current versus voltage of an organic light emitting diode display according to an embodiment and a general organic light emitting display device.
FIG. 5 is a graph showing a comparison of leakage currents between the organic light emitting display device according to the embodiment and the general organic light emitting display device.
6 is a graph and a table for comparing the lifespan of an organic light emitting display device according to an embodiment and a general organic light emitting display device.
7 is a graph showing a comparison of the lifetimes of red (Red), green (Green), and blue (Blue) elements of the organic light emitting display device according to the embodiment and a general organic light emitting display device.
8A to 8E are cross-sectional views illustrating a method of manufacturing an organic light emitting display device according to another exemplary embodiment.
9A and 9B are tables and graphs comparing the efficiency and lifespan of an organic light emitting diode display according to embodiments and a general organic light emitting display device.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same components are given the same reference numerals as much as possible even though they are indicated on different drawings. In addition, in describing the embodiments of the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

In addition, in describing the components of the invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the components from other components, and the essence, order, or order of the components are not limited by the terms. When a component is described as being “connected”, “coupled” or “connected” to another component, the component may be directly connected or connected to the other component, but another component is between each component. It should be understood that elements may be “connected,” “coupled,” or “connected.” In the same vein, when it is described that a component is formed "on" or "below" another component, the component is both formed directly on the other component or indirectly through another component. should be understood as including

As used herein and in the appended claims, unless otherwise indicated, the following terms have the following meanings.

"Halo" or "halogen" means fluorine (F), bromine (Br), chlorine (Cl) or iodine (I), unless otherwise specified.

"Alkyl" or "alkyl group" has a single bond of 1 to 60 carbon atoms, unless otherwise specified, a straight chain alkyl group, a branched chain alkyl group, a cycloalkyl (alicyclic) group, an alkyl-substituted cycloalkyl group, a cycloalkyl-substituted It refers to a radical of a saturated aliphatic functional group including an alkyl group.

"Haloalkyl group" or "halogenalkyl group" means an alkyl group substituted with halogen unless otherwise specified.

"Heteroalkyl group" means that at least one of the carbon atoms constituting the alkyl group is substituted with a heteroatom.

Unless otherwise specified, "alkenyl group" or "alkynyl group" each has a double bond or a triple bond having 2 to 60 carbon atoms, and includes a straight or branched chain group, but is not limited thereto.

"Cycloalkyl" means an alkyl forming a ring having 3 to 60 carbon atoms, unless otherwise specified, but is not limited thereto.

"Alkoxyl group", "alkoxy group", or "alkyloxy group" means an alkyl group to which an oxygen radical is attached, and has 1 to 60 carbon atoms unless otherwise specified, but is not limited thereto.

"Alkenoxyl group", "alkenoxy group", "alkenyloxyl group", or "alkenyloxy group" means an alkenyl group to which an oxygen radical is attached, and has 2 to 60 carbon atoms, unless otherwise specified, wherein is not limited to

"Aryloxyl group" or "aryloxy group" means an aryl group to which an oxygen radical is attached, and has 6 to 60 carbon atoms unless otherwise specified, but is not limited thereto.

“Aryl group” and “arylene group” each have 6 to 60 carbon atoms unless otherwise specified, but are not limited thereto. An aryl group or an arylene group means a single ring or multiple ring aromatic, and includes an aromatic ring formed by adjacent substituents joining or participating in a reaction. For example, the aryl group may be a phenyl group, a biphenyl group, a fluorene group, or a spirofluorene group.

The prefix “aryl” or “ar” refers to a radical substituted with an aryl group. For example, an arylalkyl group is an alkyl group substituted with an aryl group, an arylalkenyl group is an alkenyl group substituted with an aryl group, and the radical substituted with an aryl group has the number of carbon atoms described herein.

"Heteroalkyl" means an alkyl containing one or more heteroatoms, unless otherwise specified. "Heteroaryl group" or "heteroarylene group" means an aryl group or arylene group having 2 to 60 carbon atoms each including at least one heteroatom, unless otherwise specified, and is not limited thereto, and includes single ring and multiple It includes at least one of the rings, and may be formed by bonding adjacent functional groups.

"Heterocyclic group" includes one or more heteroatoms, has 2 to 60 carbon atoms, includes at least one of a single ring and multiple rings, and includes heteroaliphatic rings and heteroaromatic rings, unless otherwise specified. It may be formed by combining adjacent functional groups.

"Heteroatom" refers to N, O, S, P or Si unless otherwise specified.

Unless otherwise specified, the term "aliphatic" as used herein means an aliphatic hydrocarbon having 1 to 60 carbon atoms, and "aliphatic ring" means an aliphatic hydrocarbon ring having 3 to 60 carbon atoms.

Unless otherwise specified, the term "ring" as used herein refers to a fused ring consisting of an aliphatic ring having 3 to 60 carbon atoms, an aromatic ring having 6 to 60 carbon atoms, a heterocycle having 2 to 60 carbon atoms, or a combination thereof, saturated or unsaturated rings.

Other heterocompounds or heteroradicals other than the above-mentioned heterocompounds include one or more heteroatoms, but are not limited thereto.

Unless otherwise specified, "carbonyl" is represented by -COR', where R' is hydrogen, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, and 2 carbon atoms. to 20 alkenyl group, C2 to C20 alkynyl group, or a combination thereof.

Unless otherwise specified, "ether" is represented by -RO-R', where R or R' are each independently hydrogen, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, or an aryl group having 6 to 30 carbon atoms. A cycloalkyl group having 30, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, or a combination thereof.

1 is a system configuration diagram of an organic light emitting display device to which embodiments are applied.

Referring to FIG. 1 , the organic light emitting display device 100 includes an organic light emitting display panel 140 , a data driver 120 , a gate driver 130 , a timing controller 110 , and the like.

First, the timing controller 110 controls the data driver 120 based on external timing signals such as vertical/horizontal synchronization signals Vsync and Hsync input from the host system, image data data, and a clock signal CLK. A data control signal DCS for controlling the data and a gate control signal GCS for controlling the gate driver 130 are output. In addition, the timing controller 110 may convert image data (data) input from the host system into a data signal format used by the data driver 120 and supply the converted image data (data') to the data driver 120 . have.

In response to the data control signal DCS input from the timing controller 110 and the converted image data data', the data driver 120 converts the image data data' to a data signal (a voltage value corresponding to a grayscale value). It is converted into an analog pixel signal or data voltage) and supplied to the data line.

The gate driver 130 sequentially supplies a scan signal (gate pulse, scan pulse, or gate-on signal) to the gate line in response to the gate control signal GCS input from the timing controller 110 .

Meanwhile, each unit pixel region P on the organic light emitting display panel 140 may be formed in a region defined by the data lines D1 to Dm and the gate lines G1 to Gn and arranged in a matrix form. , a first electrode (not shown), a second electrode (not shown), and at least one organic light emitting device (OLED) including an organic layer (not shown). The organic light emitting layer (not shown) included in each organic layer may include at least one organic light emitting layer or a white organic light emitting layer among organic light emitting layers for red, green, blue, and white.

The organic light emitting display device 100 may include a passivation layer (not shown) disposed on the second electrode, which may include an organic layer (not shown) or internal elements (eg, a semiconductor layer of a transistor). ) to protect it from the external environment.

Here, the passivation layer (not shown) may be made of a semiconductor material. The passivation layer (not shown) has the effect of improving electrical properties by reducing deterioration of the second electrode (not shown) by not only increasing light efficiency through a difference in refractive index, but also having conductive properties when voltage is applied. In addition, an electron transport layer (not shown) included in an organic layer (not shown) made of a specific compound improves electron injection characteristics, thereby increasing the lifespan of the blue light emitting device (B), and accordingly, the organic light emitting diode display 100 itself. It also has the effect of increasing lifespan.

Meanwhile, after the passivation layer (not shown) according to the embodiments is laminated on the second electrode (not shown), a heat treatment process may be performed. This has the effect of improving the reliability of the organic light emitting display device 100 and extending the life of the organic light emitting diode display 100 by improving the characteristics of the bonding surface between the passivation layer (not shown) and the second electrode (not shown).

In this specification, the first electrode (not shown) may be an anode, may be described as having the same meaning as an anode or a pixel electrode, and the second electrode (not shown) may be a cathode, and a cathode electrode ( cathode) or the common electrode.

Hereinafter, specific embodiments will be described with reference to the drawings.

2A is a schematic structural diagram of an organic light emitting diode display according to example embodiments, and FIG. 2B is a schematic cross-sectional view of an organic light emitting display device according to an exemplary embodiment.

The organic light emitting display device 100 shown in FIG. 2B is shown as an example for convenience of description, and the organic light emitting display device 100 according to the embodiments is not limited thereto and may be formed in various structures. It should be noted.

의 화학식으로 표시되는 화합물로 이루어진 전자수송층(Electron Transfer Layer, ETL, 236)을 포함하는 유기층(230), 유기층 상에 형성된 제2전극(240) 및 제2전극(240) 상에 형성되고 반도체 물질로 이루어진 패시베이션층(250)을 포함할 수 있다. Referring to FIGS. 2A and 2B , the organic light emitting display device 100 includes a first electrode 220 formed on a substrate 202 , formed on the first electrode 220 , and an organic light emitting layer (Emission Layer, EL, 234) and

The organic layer 230 including an electron transport layer (ETL, 236) made of a compound represented by the formula of It may include a passivation layer 250 made of

In the formula, n is a natural number from 0 to 2, X is O, S or NR, R, R ¹ , R ² , R ³ , L and Ar are independently of each other, an aryl group having 6 to 60 carbon atoms, a fluorenyl group, a heterocyclic group having 2 to 60 carbon atoms including at least one heteroatom among O, N, S, Si and P, and 3 to A fused ring group of a 60 aliphatic ring and an aromatic ring having 6 to 60 carbon atoms, an alkyl group having 1 to 50 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an alkoxyl group having 1 to 30 carbon atoms, 6 carbon atoms to 30 may be selected from the group consisting of aryloxy groups.

Here, the organic layer 230 may include a hole transfer layer (HTL, 232 ), an organic light emitting layer 234 , and an electron transport layer 236 sequentially stacked on the first electrode 220 . Although not shown, the organic layer 230 may further include a hole injection layer (HIL) and an electron injection layer (EIL).

The light emission method of the organic light emitting display device 100 includes a top emission method in which the light emission direction is from the organic layer 230 to the second electrode 240 and the organic layer 230 to the first electrode 220 direction. It is divided into bottom emission, and in the present specification, the top emission method has been mainly described for convenience of description, but it should be noted that the present disclosure is not limited thereto, and may also be applied to the bottom emission method.

First, the substrate 202 is not only a glass substrate, but also a plastic substrate including PET (Polyethylen terephthalate), PEN (Polyethylen naphthalate), polyimide, etc. Indium (ITO) that can transmit light toward the substrate. It may be provided as a transparent substrate such as tin oxide) or indium zinc oxide (IZO).

In addition, a buffering layer for blocking penetration of impurity elements may be further provided on the substrate 202 . The buffer layer may be formed of a single layer or multiple layers of silicon nitride or silicon oxide.

On the other hand, on the substrate 202, at least one metal or alloy of Al, Pt, Pd, Ag, Mg, Au, Ni, Nd, Ir, Cr, Li, Ca, Mo, Ti, W, Cu, a single layer or A gate electrode 204 that can be formed in multiple layers, a gate insulating film 206 formed of an inorganic insulating material or an organic insulating material, amorphous silicon or IGZO (Indium Galium Zinc Oxide), ZTO (Zinc Tin Oxide), ZIO ( A transistor including the semiconductor layer 208 made of zinc indium oxide) and the like and the source/drain electrodes 210 may be formed.

A planarization layer 212 formed of an inorganic insulating material or an organic insulating material is positioned on the transistor, and a first electrode 220 connected to the source/drain electrodes 210 through a contact hole of the planarization layer 212 is formed.

Here, the first electrode 220 has a relatively large work function value to serve as an anode electrode (anode), and a transparent conductive material, for example, a metal oxide such as ITO or IZO, ZnO:Al or SnO ₂ :Sb and mixtures of metals and oxides, such as poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxy)thiophene] (PEDT), polypyrrole and polyaniline It may be made of a conductive polymer or the like. In addition, the first electrode 220 may include a carbon nano tube, graphene, silver nano wire, or the like.

A bank made of an inorganic insulating material for insulation and planarization may be formed at an edge of the first electrode 220 , and an organic layer 230 is formed on the first electrode 220 exposed by the bank.

Meanwhile, the organic layer 230 may have a multilayer structure including the hole transport layer 232 , the organic light emitting layer 234 , and the electron transport layer 236 , but is not limited thereto and may have a single layer structure. Although not shown, the organic layer 230 may further include a hole injection layer between the first electrode 220 and the hole transport layer 232 and an electron injection layer between the electron transport layer 236 and the second electrode 240 . . In addition, the organic layer 230 may be formed by a solvent process rather than a deposition method using various polymer materials, for example, spin coating, dip coating, doctor blading, screen printing, inkjet printing, or thermal transfer method (eg, It may be formed by a method such as Laser Induced Thermal Imaging (LITI).

The hole injection material of the hole injection layer is a material that can well inject holes from the anode at a low voltage. The highest occupied molecular orbital (HOMO) of the hole injection material may be between the work function of the positive electrode material and the HOMO of the surrounding organic material layer have. Specific examples of the hole injection material include metal porphyrine, oligothiophene, arylamine-based organic material, hexanitrile, hexaazatriphenylene, quinacridone-based organic material , perylene-based organic materials, anthraquinone, and polyaniline and polythiophene-based conductive polymers, but are not limited thereto.

A hole transport layer 232 may be formed on the hole injection layer. The hole transport layer 232 receives holes from the hole injection layer and transports holes to the organic light emitting layer 234 positioned thereon, and serves to prevent high hole mobility and stability for holes and electrons. In addition to these general requirements, heat resistance of the device is required when it is applied for vehicle body display. Substances satisfying these conditions include NPD, NPB, spiro-arylamine-based compounds, perylene-arylamine-based compounds, azacycloheptatriene compounds, bis(diphenylvinylphenyl)anthracene, silicon germanium oxide compounds, and arylamines. It may be a series of organic materials (eg, silicone-based arylamine compounds), conductive polymers, block copolymers having a conjugated portion and a non-conjugated portion, but is not limited thereto.

The organic light emitting layer 234 is a layer that emits light by recombination of holes and electrons injected from the anode and the cathode, respectively, and is made of a material with high quantum efficiency. The light emitting material is a material capable of emitting light in the visible ray region by transporting and combining holes and electrons from the hole transport layer 232 and the electron transport layer 236, respectively, and a material with good quantum efficiency for fluorescence or phosphorescence is preferable. .

Examples of the light-emitting material or compound satisfying these conditions include an 8-hydroxy-quinoline aluminum complex (Alq ₃ ), a carbazole-based compound; dimerized styryl compounds, BAlq; 10-hydroxybenzoquinoline-metal compound, benzoxazole, benzthiazole and benzimidazole series compound, poly(p-phenylenevinylene) (PPV) series polymer, spiro compound, polyfluorene, Rubrene and the like, but is not limited thereto.

The organic light emitting layer 234 may dope a small or high molecular host material with a small amount of a guest material (dopant), so that the excitation energy of the host molecule moves to the guest molecule to emit light from the guest having high quantum efficiency.

For example, in the case of a green light-emitting material, Alq ₃ is, in the case of a blue light-emitting material, BAlq (8-hydroxyquinoline beryllium salt), DPVBi(4,4'-bis(2,2-diphenylethenyl)-1,1'-biphenyl) Series, spiro material, spiro-DPVBi(Spiro-4,4'-bis(2,2-diphenylethenyl)-1,1'-biphenyl), LiPBO(2-(2-benzoxazoyl)-phenol lithium salt) , bis(diphenylvinylphenylvinyl)benzene, aluminum-quinoline metal complex, imidazole, thiazole, and oxazole metal complexes, and perylene, and BczVBi(3,3'[( 1,1'-biphenyl)-4,4'-diyldi-2,1-ethenediyl]bis(9-ethyl)-9H-carbazole; DSA (distrylamine)) may be doped in a small amount. In the case of a red light-emitting material, DCJTB([2-(1,1-dimethylethyl)-6-[2-(2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H) ,5H-benzo(ij)quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene]-propanedinitrile) can be used by doping a small amount. When the organic light emitting layer 234 is formed using a process such as inkjet printing, roll coating, or spin coating, a polyphenylenevinylene (PPV) polymer or a polymer such as polyfluorene is used as the organic light emitting layer. (234) can be used.

For another example, as a host material, a carbazole derivative (eg, 4,4'-bis(9-carbazolyl)biphenyl (CBP)) or a triphenylamine derivative, an oxadiazole derivative , 1,2,4-triazole derivatives or 1,3,5-triazine derivatives, and may be a metal complex, for example, an iridium complex or a platinum complex as a guest material.

An electron transport layer 236 is positioned on the organic light emitting layer 234 . As the electron transport layer 236 , a material capable of efficiently transporting injected electrons with high electron injection efficiency from the second electrode 240 positioned thereon is required. For this purpose, a material having high electron affinity and electron movement speed and excellent stability to electrons is used. Specific examples of the electron transport material satisfying the above conditions include, but are not limited to, an Al complex of 8-hydroxyquinoline, a complex including Alq3, an organic radical compound, and a hydroxyflavone-metal complex.

의 화학식으로 표시되는 화합물일 수 있다. 보다 구체적으로

의 화학식으로 표시될 수 있다. 화학식들에서, n은 0 내지 2의 자연수이고, X는 O, S 또는 NR이며, R, L 및 Ar은 서로 독립적으로, 탄소수 6에서 60의 아릴기, 탄소수 2에서 60의 헤테로고리기, 탄소수 3에서 60의 지방족고리와 탄소수 6에서 60의 방향족고리의 융합고리기로 이루어진 군에서 선택된다.The electron transport layer 236 according to an embodiment is, for example,

It may be a compound represented by the formula of more specifically

It can be represented by the chemical formula of In the formulas, n is a natural number of 0 to 2, X is O, S or NR, R, L, and Ar are each independently of each other, an aryl group having 6 to 60 carbon atoms, a heterocyclic group having 2 to 60 carbon atoms, a carbon number It is selected from the group consisting of a fused ring group of an aliphatic ring having 3 to 60 carbon atoms and an aromatic ring having 6 to 60 carbon atoms.

The electron transport layer 236 represented by this chemical formula interacts with a passivation layer 250 to be described later to reduce deterioration of the second electrode 240 and improve electron injection characteristics of the organic light emitting diode display 100 . can increase lifespan. This will be described in detail in the parts related to FIGS. 3 to 7 .

Meanwhile, an electron injection layer may be stacked on the electron transport layer 236 . The electron injection layer includes a _{metal complex compound such as Balq, Alq 3} , Be(bq) ₂ , Zn(BTZ) ₂ , Zn(phq) ₂ , PBD, spiro-PBD, TPBI, Tf-6P, etc., and an imidazole ring ) may be manufactured using a low molecular weight material including an aromatic compound or a boron compound, but is not limited thereto.

In FIG. 2B , the organic layer 230 including the hole transport layer 232 , the organic light emitting layer 234 and the electron transport layer 236 is illustrated by way of example, but the organic layer 230 is not limited thereto, and the hole blocking layer, the electron It may further include layers such as a blocking layer, a light emitting auxiliary layer, a hole transport auxiliary layer or a buffer layer.

Then, when the second electrode 240 formed on the organic layer 230 functions as a cathode electrode, the second electrode 240 is formed of a metal material having a relatively small work function value, for example, aluminum (Al), an aluminum alloy, It may be made of any one or more of silver (Ag), magnesium (Mg), and gold (Au).

A passivation layer 250 is formed on the second electrode 240 . Hereinafter, the passivation layer 250 may be referred to as a capping layer (CPL).

The conventional passivation layer has a hydrophobic property in consideration of mechanical strength, moisture permeability, film formation easiness, productivity, etc., and inorganic insulating materials such as SiON, silicon nitride (SiNx), silicon oxide (SiOx), aluminum oxide (AlOx), etc. Alternatively, it may be formed of any one of an organic insulating material including benzocyclobutene (BCB) and an acryl-based resin.

However, the passivation layer 250 according to the embodiments may be formed of a semiconductor material, for example, may include zinc (Zn) or antimony (Sb), more specifically, the semiconductor material is a II-VI compound a semiconductor material or a III-V compound semiconductor material. II-VI compound semiconductor material is zinc oxide (ZnO), zinc sulfide (ZnS), zinc selenide (ZnSe), zinc telluride (ZnTe), cadmium sulfide (Cadmium Sulfide) , CdS), one of Cadmium Selenide (CdS) and Cadmium Telluride (CdTe), and the III-V compound semiconductor material is Aluminum Phosphide (AlP), Aluminum Arsenide , AlAs), Aluminum Antimonide (AlSb), Gallium Nitride (GaN), Gallium Phosphide (GaP), Gallium Arsenide (GaAs), Gallium Antimonide ( Gallium Antimonide (GaSb), Indium Nitride (InN), Indium Phosphide (InP), Indium Arsenide (InAs), Indium Antimonide (InSb) However, it is not limited thereto.

The passivation layer 250 may be of a film type, but is not limited thereto, and by slowing the penetration of moisture or oxygen, the organic layer 230 sensitive to moisture and oxygen may be prevented from coming into contact with moisture. In addition, the passivation layer 250 is formed as a single layer, but is not limited thereto and may be formed as a plurality of layers.

In addition, the passivation layer 250 may be deposited by a physical vapor deposition method such as sputtering or thermal evaporation or chemical vapor deposition, but is not limited thereto.

The passivation layer 250 may have a thickness of 300 Å to 600 Å, but is not limited thereto. When the thickness is less than 300 Å, there may be a problem in preventing the penetration of moisture and oxygen, and when the thickness is greater than 600 Å, the thickness of the organic light emitting display device 100 is increased to increase the thickness of the flexible display device. It can be difficult to apply.

The thickness of the above-described organic layer 230 may be m/2 times the emission wavelength of the organic layer 230 (where m is a natural number), but is not limited thereto. In this case, the light reflected between the first electrode 220 and the second electrode 240 is extinguished through destructive interference to obtain a microcavity effect that increases the efficiency of the emitted light.

Meanwhile, the refractive index of the passivation layer 250 may be 1.8 to 3.6, and the refractive index of the passivation layer 250 may be greater than that of the second electrode 240 . This is to improve the efficiency of the organic light emitting display device 100 by reducing an optical loss of light emitted from the organic light emitting layer 234 toward the second electrode 240 .

3 is a diagram illustrating paths of lights in an organic light emitting diode display according to example embodiments.

Referring to FIG. 3 , the organic layer 230 , the second electrode 240 , the passivation layer 250 , and air 360 outside the organic light emitting display device 100 illustrated in FIG. 2 are shown. The second electrode 240 may be, for example, an alloy of magnesium and silver, and the passivation layer 250 may be formed of zinc selenide, which is a II-VI compound semiconductor material.

The following refractive indices n ₁ to n ₄ and thicknesses t ₁ and t ₃ are only for convenience of description, and the organic light emitting display device 100 according to the embodiments is not limited thereto, and various refractive indices and thicknesses are provided. can be formed with

The refractive index (n ₁ ) of the organic layer 230 is 1.8, the refractive index (n _{2 ) of the second electrode 240 is 0.2, the refractive index (n 3} ) of the passivation layer 250, and the refractive _{index (n 4} ) of the air 360 ) may be 1.0. At this time, when light passes from a medium having a small refractive index to a medium having a large refractive index according to Snell's law, an effect of collecting the light may appear.

More specifically, among the light emitted from the organic light emitting layer 234 of the organic layer 230 , the light L _{11 exceeding the critical angle θ 1} at the interface is totally reflected, and the light L _{12 below the critical angle θ 1 .} ) passes through the interface and is transmitted to the second electrode 240 . In this case, when the thickness t ₁ of the organic layer 230 is m/2 times the emission wavelength (where m is a natural number), the total reflected light L ₁₁ may be extinguished by the microcavity effect described above.

At this time, the refractive index of the second electrode (240), (n ₂₎ is 0.2, and the refractive index of the passivation layer (250), (n ₃₎ is 1.8 is because, the second by the difference between the refractive index (n ₁₎ of the organic layer 230 _{The light L 2} dispersed while passing through the electrode 240 is bent in the normal direction compared _{to the light L 2} incident at the interface between the second electrode 240 and the passivation layer 250 . Thereafter, in the passivation layer 250 , the light L _{31 exceeding the critical angle θ 3} is totally reflected, and the totally reflected light L ₃₁ can be annihilated by the aforementioned microcavity effect, and is greater than the _{critical angle θ 3 . Light L 32} incident at a small angle is dispersed in the air 360 . Meanwhile, the thickness t ₃ of the passivation layer 250 may be 300 Å to 600 Å.

_{Thereafter, since the refractive index n 4} of the air 360 _{is smaller than the refractive index n 3} of the passivation layer 250, _{the light L 32 that} has been deflected in the normal direction of the interface is dispersed again and the viewing angle can be improved.

According to the difference in refractive index, the organic light emitting display device 100 may minimize light loss due to dispersion and total reflection of light, improve a viewing angle, and increase light efficiency.

Hereinafter, in FIGS. 4 to 7 , the passivation layer 250 is formed of a semiconductor material and the electron transport layer 236 is formed of a specific compound. Explain.

4 is a diagram illustrating a graph comparing current versus voltage between an organic light emitting diode display according to an embodiment and a general organic light emitting display device, and FIG. 5 is an organic light emitting display device according to the embodiment and a general organic light emitting diode display. It is a view showing a graph comparing leakage current of a light emitting display device, and FIG. 6 is a view showing a graph and a table comparing the lifespan of the organic light emitting display device according to the embodiment and a general organic light emitting display device, FIG. 7 is a graph showing a comparison of the lifespans of the red (Red), green (Green), and blue (Blue) elements of the organic light emitting display device according to the embodiment and a general organic light emitting display device.

의 화학식으로 표현되는 화합물로 이루어진 경우를 나타낸다. 다만, 이는 설명의 편의를 위한 것이고, 패시베이션층(250)의 재질은 이에 제한되지 않는다.4 and 5 , in the case of a general organic light emitting diode display, a passivation layer is formed of an organic material. On the other hand, in the organic light emitting display device 100 according to the embodiment, the passivation layer 250 is formed of a semiconductor material, and the passivation layer 250 is

represents a case consisting of a compound represented by the formula of However, this is for convenience of description, and the material of the passivation layer 250 is not limited thereto.

In this case, X is O, S or NR, R, R ¹ , R ² , R ³ are each independently at least one of an aryl group having 6 to 60 carbon atoms, a fluorenyl group, O, N, S, Si and P A heterocyclic group having 2 to 60 carbon atoms, including a heteroatom of It may be selected from the group consisting of an alkynyl group having 2 to 20 carbon atoms, an alkoxyl group having 1 to 30 carbon atoms, and an aryloxy group having 6 to 30 carbon atoms.

When the passivation layer 250 is formed of a semiconductor material, when a voltage is applied to the first electrode 220 and the second electrode 240 , more current may flow than in the general case.

In other words, when the second electrode 240 is formed to have a relatively thin thickness, the second electrode 240 may have a relatively high resistance and thus may be deteriorated or electrical characteristics may be deteriorated. At this time, when the passivation layer 250 is formed of a semiconductor material and the electron transport layer 236 is formed of the above-described compound, when the electrons are supplied to the organic light emitting layer 234 through the electron transport layer 236, the passivation layer 250 is Since it has conductivity, it is possible to lower the resistance value, and accordingly, deterioration or deterioration of electrical characteristics can be prevented. That is, the passivation layer 250 functions as a conductor, thereby increasing the thickness of the second electrode 240 and reducing the sheet resistance value.

Accordingly, as shown in FIG. 5 , the amount of current used as thermal energy is reduced, so that the amount of leakage current is reduced.

의 화학식으로 표현되는 화합물로 전자수송층(ETL_2)을 형성하고, 패시베이션층(250)을 반도체 물질로 형성한 경우이고, d는

의 화학식으로 표현되는 화합물로 전자수송층(ETL_2)을 형성하고, 패시베이션층을 일반적인 유기화합물로 형성한 경우를 나타낸다. 또한 도 6은 제2전극(240)은 마그네슘과 은의 합금을 사용하였으며, 일반적인 유기화합물로 이루어진 패시베이션층의 굴절률은 1.8이고, 반도체 물질로 이루어진 패시베이션층의 굴절률은 2.8인 경우의 그래프를 나타낸다. 6, a is a case in which the electron transport layer (ETL_1) is formed with a general organic compound, and the passivation layer is also formed with a general organic compound, b is a general organic compound to form an electron transport layer (ETL_1), and the passivation layer is formed of a semiconductor material, and c is according to an embodiment

In the case where the electron transport layer (ETL_2) is formed with a compound represented by the formula of and the passivation layer 250 is formed of a semiconductor material, d is

A case in which the electron transport layer (ETL_2) is formed with a compound represented by the chemical formula of and the passivation layer is formed of a general organic compound is shown. In addition, FIG. 6 shows a graph in the case where an alloy of magnesium and silver is used for the second electrode 240, a passivation layer made of a general organic compound has a refractive index of 1.8, and a passivation layer made of a semiconductor material has a refractive index of 2.8.

Comparing a and b, it can be seen that the luminance efficiency increases from 4.7 cd/A to 5.5 cd/A, and the lifetime increases slightly accordingly. On the other hand, comparing c and d, due to the application of the electron transport layer 236 made of a specific compound and the passivation layer 250 made of a semiconductor material, the luminance efficiency over time is high, and the lifespan is relatively large. can see.

This is because, as described above, the passivation layer 250 made of a semiconductor material becomes conductive and prevents deterioration of the device and deterioration of electrical characteristics.

의 화학식으로 표현되는 화합물로 전자수송층(ETL_2)을 형성하고, 패시베이션층(250)을 반도체 물질로 형성한 경우의 그래프이다.Referring to FIG. 7 , changes in lifespan according to red (R), blue (B), and green (G) light emitting devices constituting the organic light emitting layer 234 are shown. (a) is a graph when the electron transport layer 236 is formed with a general organic compound and a passivation layer is formed with a general organic compound. Meanwhile, (b) according to an embodiment

It is a graph when the electron transport layer (ETL_2) is formed with the compound represented by the chemical formula of , and the passivation layer 250 is formed of a semiconductor material.

In the case of a general organic light emitting display device as shown in (a), the lifespan of the blue light emitting device (B) among the red light emitting device (R), the green light emitting device (G), and the blue light emitting device (B) is the same as that of the remaining light emitting devices. Since it is only about half, the problem is alleviated by maximizing the aperture ratio of the blue light emitting device B and lowering the aperture ratio of the red light emitting device R and the green light emitting device.

On the other hand, in the case of (b), it can be seen that the lifespan of the blue light emitting device B appears at the same level as that of the other light emitting devices R and G. It can be seen that the conductive properties of the passivation layer 250 prevent deterioration of the electrical properties of the organic light emitting display device 100, and the electron transport layer 236 made of the above-described compound improves the electron injection properties, thereby increasing the lifespan. .

8A to 8E are cross-sectional views illustrating a method of manufacturing an organic light emitting display device according to another exemplary embodiment.

의 화학식으로 표시되는 화합물로 이루어진 전자수송층(Electron Transfer Layer, ETL, 236)을 포함하는 유기층(230)을 형성하는 단계, 유기층(230) 상에 제2전극(240)을 형성하는 단계, 제2전극(240) 상에 반도체 물질로 이루어진 패시베이션층(250)을 형성하는 단계 및 열처리 단계를 포함할 수 있다.8A to 8E , a method of manufacturing an organic light emitting display device includes forming a first electrode 220 on a substrate 202 , on the first electrode 220 , an organic light emitting layer (Emission Layer, EL, 234) and

Forming an organic layer 230 including an electron transport layer (ETL, 236) made of a compound represented by the formula of, forming a second electrode 240 on the organic layer 230, the second It may include forming a passivation layer 250 made of a semiconductor material on the electrode 240 and a heat treatment step.

First, a transistor is formed on a substrate of the organic light emitting diode display 100 . The transistor including the gate electrode 204, the gate insulating film 206, the semiconductor layer 208, and the source/drain electrodes 210 is formed by physical vapor deposition or chemical vapor deposition. It is deposited through a deposition process and patterned through an etching process.

A planarization layer 212 in which a contact hole is located is formed on the transistor through a deposition process, and a first electrode 220 connected to the source/drain electrode 210 through the contact hole is formed on the planarization layer 212 after deposition and patterning. do. Here, the first electrode 220 functions as an anode for supplying holes to the organic layer 230 .

Meanwhile, the bank 222 is formed along the edge of the first electrode 220 . The bank 222 may be formed of an inorganic material by a deposition and etching process or an organic material by a solution process.

Subsequently, the step of forming the organic layer 230 on the first electrode 220 exposed by the bank 332 is performed.

8B to 8E, for convenience of explanation, a case in which the organic layer 230 is composed of three layers of the hole transport layer 232, the organic light emitting layer 234, and the electron transport layer 236 is illustrated, but this is for convenience of explanation. In addition, the organic layer 230 of the organic light emitting display device 100 may be formed of a various number of layers.

The organic layer 230 may be deposited by physical vapor deposition or chemical vapor deposition, or may be formed by a solution process such as inkjet printing. Here, in the case of the solution process, only some of the plurality of layers may be formed by the solution process.

Since the material constituting each layer of the organic layer 230 has been described above, a description thereof will be omitted.

Thereafter, the second electrode 240 is formed over the entire surface of the organic light emitting display panel 140 on the organic layer 230 . The second electrode 240 may be a cathode that supplies electrons to the organic layer 230 , and may be formed by various deposition processes.

Next, a step of forming the passivation layer 250 made of a semiconductor material on the second electrode 240 is performed.

Here, the semiconductor material may include zinc (Zn) or antimony (Sb), and may include an I-VI compound semiconductor material or a III-V compound semiconductor material. A detailed description thereof has been described above.

When a voltage is applied to the first electrode 220 and the second electrode 240 of the organic light emitting diode display 100 , the passivation layer 250 becomes conductive, so that the sheet resistance of the second electrode 240 is reduced. The leakage current is prevented and the deterioration of the second electrode 240 is prevented, thereby increasing the reliability and lifespan of the organic light emitting display device 100 .

The refractive index of the passivation layer 250 is 1.8 to 3.6, and has a larger value than that of the second electrode 240 . Therefore, it acts as an optical mechanism, and performs a function of increasing the light efficiency through the refractive index difference.

In addition, the passivation layer 250 may have a thickness of 300 Å to 600 Å, and the electron injection characteristic is improved through interaction with the electron transport layer material, and the lifespan of the blue light emitting device B is increased.

On the other hand, the step of forming the passivation layer 250 is a step of forming the passivation layer 250 by physical vapor deposition (Physical Vapor Deposition) or chemical vapor deposition (Chemical Vapor Deposition).

The passivation layer 250 functions to protect internal elements including the organic layer 230 from external oxygen or moisture.

Finally, the step of heat-treating the organic light emitting display device 100 on which the passivation layer 250 is deposited is performed.

Referring to the enlarged view of FIG. 8D , in the process of depositing the passivation layer 250 , the bonding state of the interface between the passivation layer 250 and the second electrode 240 may be poor.

Specifically, during the deposition process, the thickness of the passivation layer 250 may not be uniform, and in a certain area, the particles are agglomerated, and in another area, the particles are stacked in the form of an island with a small density. can For example, in the case of a thermal deposition process, which is one of the physical chemical vapor deposition methods, after the material constituting the passivation layer 250 is vaporized, it becomes a solid again on the second electrode 240 and deposition is performed, this process may be deposited at a non-uniform density, and thus, an island shape may appear or a problem may occur in that an adhesion area at the adhesion interface is not sufficiently formed.

Such poor adhesion may cause deterioration of the device and shorten the lifespan of the organic light emitting display device 100 .

However, in the embodiment of the present invention, as shown in FIG. 8E , the bonding state or bonding state between the second electrode 240 and the passivation layer 250 is improved.

Here, the heat treatment step is a step of heating the organic light emitting display device 100 at a temperature lower than the lowest temperature among the glass transition temperatures (Tg) of each compound included in the organic layer 230 . That is, when heating is performed at a temperature higher than the glass transition temperature of the compound constituting the organic layer 230 , the physical properties of the organic layer 230 change, so that visibility and luminance decrease, and color reproducibility may be reduced. , it is required to have a temperature lower than the glass transition temperature so that no change occurs in the organic layer 230 .

However, within this temperature range, the higher the heating temperature of the organic light emitting diode display 100 is, the larger the bonding area between the second electrode 240 and the passivation layer 250 may be. For example, when the lowest value of each glass transition temperature value of the materials included in the organic layer 230 is 250° C., when heated to a temperature close to 250° C., the interlayer interfacial bonding properties can be most improved. have.

In other words, the heat treatment step has an effect of heating the organic light emitting display device 100 to melt and uniformly distribute the materials constituting the passivation layer 250 deposited with a non-uniform density. In other words, the bonding area between the second electrode 240 and the passivation layer 250 is increased, the aggregated materials are dispersed, and the thickness becomes uniform. Accordingly, the reliability of the organic light emitting display device 100 may be improved, and the lifespan of the organic light emitting display device 100 may be extended. Here, the junction area refers to an area in which the second electrode 240 and the passivation layer 250 are in contact with (or in close contact with).

9A and 9B are tables and graphs comparing the efficiency and lifespan of an organic light emitting diode display according to embodiments and a general organic light emitting display device.

9A and 9B, Sample 1 corresponds to a general organic light emitting display device, and Sample 2 is an organic light emitting diode including a passivation layer 250 made of zinc selenide (ZnSe) according to an embodiment. Corresponds to the display device 100, and Sample3 corresponds to the organic light emitting display device 100 including a passivation layer 250 made of zinc selenide (ZnSe) and subjected to heat treatment according to an embodiment.

Meanwhile, the samples used the organic layer 230 emitting a similar color (see color coordinates), and in the table, T95 means the time taken for the lifespan of the organic light emitting display device 100 to reach 95%.

9A and 9B, compared to Sample 1 (Sample 1), Sample 2 (Sample 2) has higher efficiency (5.5 cd/A) under the same driving voltage, and the lifetime (T95) is also longer by 60 hours ( 180 Hrs).

On the other hand, in the case of Sample 3 (Sample) in which the organic light emitting display device 100 has been subjected to the heat treatment step, the efficiency is the same as that of Sample 2 (Sample 2), but it can be seen that the lifetime T95 is significantly increased (350 hrs). This is an effect that occurs because internal elements including the organic layer 230 are protected from the external environment by improving the bonding or contact characteristics of the second electrode 240 and the passivation layer 250 due to the heat treatment.

In summary, in the organic light emitting display device 100 , the passivation layer 250 made of a semiconductor material not only increases light efficiency through a difference in refractive index, but also has conductive properties when a voltage is applied, thereby preventing deterioration of the second electrode 240 . It has the effect of improving the electrical properties by reducing it. In addition, since the electron transport layer 236 made of a specific compound improves electron injection characteristics, the lifespan of the blue light emitting device B is increased, and thus the lifespan of the organic light emitting diode display 100 itself is increased.

In addition, when the passivation layer 250 made of a semiconductor material is deposited and then heat treatment is performed on the organic light emitting display device 100 , the interfacial bonding characteristics between the second electrode 240 and the passivation layer 250 are improved to improve the organic light emitting display. An effect of improving the reliability and lifespan of the device 100 occurs.

The embodiments have been described above with reference to the drawings, but the present invention is not limited thereto.

Terms such as "include", "compose" or "have" described above mean that the corresponding component may be embedded unless otherwise stated, so it does not exclude other components. It should be construed as being able to further include other components. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs, unless otherwise defined. Terms commonly used, such as those defined in the dictionary, should be interpreted as being consistent with the meaning of the context of the related art, and are not interpreted in an ideal or excessively formal meaning unless explicitly defined in the present invention.

The above description is merely illustrative of the technical spirit of the present invention, and various modifications and variations will be possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

202: substrate 204: gate electrode
212: planarization layer 222: bank
220: first electrode 206: organic layer
230: organic layer 232: hole transport layer
236: electron transport layer 234: organic light emitting layer
240: second electrode 250: passivation layer

Claims (12)

a first electrode positioned on the substrate;
It is located on the first electrode, and an organic light emitting layer (Emission Layer, EL) and

An organic layer comprising an electron transport layer (ETL) consisting of a compound represented by the formula of;
a second electrode positioned on the organic layer; and
and a passivation layer located on the second electrode and made of a semiconductor material,
The semiconductor material is an organic light emitting display device including a III-V compound semiconductor material:
In the above formula,
wherein X is O, S or NR;
Wherein R, R ¹ , R ² and R ³ are each independently a fusion of an aryl group having 6 to 60 carbon atoms, a heterocyclic group having 2 to 60 carbon atoms, an aliphatic ring having 3 to 60 carbon atoms and an aromatic ring having 6 to 60 carbon atoms. It is selected from the group consisting of cyclic groups. The method of claim 1,
and the semiconductor material includes antimony (Sb). The method of claim 1,
The III-V compound semiconductor material is aluminum phosphide (AlP), aluminum arsenide (AlAs), aluminum antimonide (AlSb), gallium nitride (GaN), gallium Gallium Phosphide (GaP), Gallium Arsenide (GaAs), Gallium Antimonide (GaSb), Indium Nitride (InN), Indium Phosphide (InP), An organic light emitting display device, characterized in that it is one of indium arsenide (InAs) and indium antimonide (InSb). The method of claim 1,
The organic light emitting display device of claim 1, wherein the passivation layer has conductivity when electrons are supplied to the organic light emitting layer through the electron transport layer. The method of claim 1,
The passivation layer has a refractive index of 1.8 to 3.6. The method of claim 1,
The organic light emitting display device, characterized in that the refractive index of the passivation layer is greater than the refractive index of the second electrode. The method of claim 1,
The passivation layer has a thickness of 300 Å to 600 Å. The method of claim 1,
and the organic layer includes a hole transport layer (HTL) sequentially stacked on the first electrode, the organic light emitting layer, and the electron transport layer. forming a first electrode on a substrate;
On the first electrode, an organic light emitting layer (Emission Layer, EL) and

Forming an organic layer comprising an electron transport layer (Electron Transfer Layer, ETL) consisting of a compound represented by the formula of;
forming a second electrode on the organic layer;
forming a passivation layer made of a semiconductor material on the second electrode; and
heat treatment step,
The method of manufacturing an organic light emitting display device, wherein the semiconductor material includes a III-V compound semiconductor material:
In the above formula,
wherein X is O, S or NR;
The R, R ¹ , R2 and R ³ are each independently a fused ring of an aryl group having 6 to 60 carbon atoms, a heterocyclic group having 2 to 60 carbon atoms, an aliphatic ring having 3 to 60 carbon atoms and an aromatic ring having 6 to 60 carbon atoms. selected from the group consisting of groups. 10. The method of claim 9,
The step of forming the passivation layer,
A method of manufacturing an organic light emitting display device, characterized in that the passivation layer is formed by physical vapor deposition or chemical vapor deposition. 10. The method of claim 9,
The heat treatment step is
The method of claim 1, wherein the organic light emitting display device is heated at a temperature lower than the lowest temperature among the glass transition temperatures (Tg) of each of the compounds included in the organic layer. 10. The method of claim 9,
In the heat treatment step,
The method of manufacturing an organic light emitting display device, characterized in that the higher the heating temperature of the organic light emitting display device, the larger the bonding area between the second electrode and the passivation layer.

Images