KR20150080406A - Organic light emitting diode display apparatus and method for fabricating the same - Google Patents

Abstract

The present invention provides an organic light emitting display apparatus and a method for manufacturing the same. The organic light emitting display apparatus includes: a first electrode located on a substrate; an organic layer which is located on the first electrode and includes an organic emission layer (EL) and an electron transfer layer (ETL) consisting of a compound represented by Chemical formula; a second electrode located on the organic layer; and a passivation layer which is located on the second electrode and is made of a semiconductor material.

Description

TECHNICAL FIELD [0001] The present invention relates to an organic light emitting diode (OLED) display device and a method of manufacturing the same,

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

2. Description of the Related Art In the field of flat panel display devices, a liquid crystal display device which has been light and consumes less power has been widely used. However, since a liquid crystal display device is a non-emissive device which can not generate light itself, ratio, a viewing angle, and a large area.

Accordingly, a new flat panel display device that can overcome the disadvantages of such a liquid crystal display device has been actively developed. One of the new flat panel display devices is an emissive device that generates light by itself, The liquid crystal display device is excellent in brightness, viewing angle, and contrast ratio, and does not require a backlight.

The organic light emitting diode displays an image using light emitted from an organic light emitting diode connected to a thin film transistor of each pixel region. The organic light emitting diode includes a light emitting layer formed of an organic material between an anode and a cathode It is a device that emits light by applying an electric field. It can be driven at a low voltage, has a relatively low power consumption, and is light and can be fabricated on a flexible substrate.

When the organic light emitting display device is driven, a large amount of current may flow through the cathode, thereby deteriorating the electrical characteristics such as deterioration, and the efficiency of the blue light emitting device is relatively small. There is a problem that the lifetime is lowered.

An object of the present invention is to provide an organic light emitting display device having improved electrical characteristics, reliability and lifetime, and a method of 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.According to an aspect of the present invention, there is provided an organic light emitting diode (OLED) display comprising: a first electrode disposed on a substrate; an organic emission layer disposed on the first electrode;

An electron transport layer (ETL) composed of a compound represented by the following chemical formula, a second electrode located on the organic layer, and a passivation layer formed on the second electrode and made of a semiconductor material.

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.According to another aspect of the present invention, there is provided a method of manufacturing an organic light emitting diode display, comprising: forming a first electrode on a substrate; forming an organic emission layer (EL)

, Forming an organic layer including an electron transport layer (ETL) made of a compound represented by the following chemical formula (1), 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.

INDUSTRIAL APPLICABILITY The organic light emitting display device and the method of manufacturing the same according to the present invention have an effect of improving the electrical characteristics and improving reliability and lifetime.

1 is a system configuration diagram of an organic light emitting display device to which embodiments are applied.
2A is a schematic structural view of an organic light emitting diode display according to embodiments.
2B is a schematic cross-sectional view of an OLED display according to an embodiment.
3 is a view showing paths of light in the organic light emitting diode display according to the embodiments.
FIG. 4 is a graph showing a current vs. voltage of an OLED display according to an embodiment of the present invention and a conventional OLED display. Referring to FIG.
FIG. 5 is a graph illustrating a comparison of leakage currents between an OLED display according to an embodiment and a conventional OLED display. Referring to FIG.
FIG. 6 is a graph showing a comparison of lifetime of an OLED display according to an embodiment and a conventional OLED display.
FIG. 7 is a graph showing a comparison of the lifetime of red, green, and blue elements of the organic light emitting display according to the embodiment and the conventional organic light emitting display.
8A to 8E are cross-sectional views illustrating a method of manufacturing an OLED display according to another embodiment of the present invention.
9A and 9B are tables and graphs comparing efficiency and lifetime of an OLED display according to an exemplary embodiment of the present invention and a conventional OLED display.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In the following description of the embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In describing the components of the invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected to or connected to the other component, It should be understood that an element may be "connected," "coupled," or "connected." In the same context, when an element is described as being formed on an "upper" or "lower" side of another element, the element may be formed either directly or indirectly through another element As will be understood by those skilled in the art.

As used in this specification and the appended claims, the following terms have the following meanings, unless otherwise stated.

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

"Alkyl" or "alkyl group ", unless otherwise specified, has a single bond of from 1 to 60 carbon atoms and includes straight chain alkyl groups, branched chain alkyl groups, cycloalkyl (cycloaliphatic) groups, alkyl- Quot; means a radical of a saturated aliphatic group, including an alkyl group,

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

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

"Alkenyl group" or "alkynyl group ", unless otherwise specified, each have a double bond or triple bond of 2 to 60 carbon atoms and include, but are not limited to, straight chain or branched chain groups.

"Cycloalkyl" means an alkyl that forms a ring having a carbon number of 3 to 60 unless otherwise stated, but is not limited thereto.

The term "alkoxyl group", "alkoxy group", or "alkyloxy group" refers to an alkyl group having an oxygen radical attached thereto,

&Quot; Alkenooxyl group ", "Alkenooxy group "," Alkenyloxy group ", or "Alkenyloxy group" means an alkenyl group having an oxygen radical attached thereto. Unless otherwise specified, .

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

"Aryl group" and "arylene group" each independently have 6 to 60 carbon atoms, but are not limited thereto. An aryl group or an arylene group means a single ring or an aromatic ring of multiple rings, and neighboring substituents include aromatic rings formed by bonding or participating in the reaction. For example, the aryl group may be a phenyl group, a biphenyl group, a fluorene group, or a spirobifluorene group.

The prefix "aryl" or "ar" means a radical substituted with an aryl group. For example, the arylalkyl group is an alkyl group substituted with an aryl group, the arylalkenyl group is an alkenyl group substituted with an aryl group, and the radical substituted with an aryl group has the carbon number described in the present specification.

"Heteroalkyl" means alkyl containing one or more heteroatoms unless otherwise specified. "Heteroaryl group" or "heteroarylene group" means an aryl or arylene group having from 2 to 60 carbon atoms, each containing at least one heteroatom unless otherwise specified, including, but not limited to, a single ring and multiple Rings, and adjacent functional devices may be formed in combination.

The term "heterocyclic group" includes at least one of a single ring and a multicyclic ring, and includes a heteroaliphatic ring and a heteroaromatic ring, unless otherwise specified, includes at least one heteroatom, has from 2 to 60 carbon atoms. Adjacent functional groups may be combined and formed.

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

Unless otherwise stated, the term "aliphatic" as used herein means an aliphatic hydrocarbon having 1 to 60 carbon atoms and an "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 of 3 to 60 carbon atoms or an aromatic ring of 6 to 60 carbon atoms or a heterocycle of 2 to 60 carbon atoms, or combinations thereof, Saturated or unsaturated ring.

Other hetero-compounds or hetero-radicals other than the above-mentioned hetero-compounds include, but are not limited to, one or more heteroatoms.

Unless otherwise specified, "carbonyl" means -COR ', wherein 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, An alkenyl group having 1 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, or a combination thereof.

Unless otherwise stated, "ether" refers to -RO-R ', wherein R or R' are each independently selected from the group consisting of hydrogen, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, A cycloalkyl group having 1 to 30 carbon atoms, 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.

1, the OLED display 100 includes an OLED 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 the vertical / horizontal synchronizing signals (Vsync, Hsync) input from the host system and the external timing signals such as the video data (data) and the clock signal (CLK) And a gate control signal (GCS) for controlling the gate driver 130. The gate control signal The timing controller 110 may convert the video data input from the host system into a data signal format used by the data driver 120 and supply the converted video data 'data' to the data driver 120 have.

In response to the data control signal DCS and the converted video data 'data' input from the timing controller 110, the data driver 120 converts the video data 'data' into a data signal Analog pixel signal or data voltage) and supplies the converted data to the data line.

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

Each unit pixel region P on the organic light emitting display panel 140 may be formed in an area defined by the data lines D1 to Dm and the gate lines G1 to Gn and arranged in a matrix form , At least one organic light emitting diode (OLED) including a first electrode (not shown), a second electrode (not shown), and 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 diode display 100 may include a passivation layer (not shown) located on the second electrode, which may include an organic layer (not shown) or internal elements (e.g., ) From the external environment.

Here, the passivation layer (not shown) may be formed of a semiconductor material. Such a passivation layer (not shown) not only increases light efficiency through a difference in refractive index but also has a conductive property when a voltage is applied, thereby reducing the deterioration of the second electrode (not shown), thereby improving the electrical characteristics. Further, 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 lifetime of the blue light emitting device B, It has an effect of increasing the life span.

Meanwhile, after the passivation layer (not shown) according to the embodiments is stacked on the second electrode (not shown), a heat treatment process can be performed. This improves the characteristics of the bonding surface between the passivation layer (not shown) and the second electrode (not shown), thereby improving the reliability of the OLED display 100 and extending the service life thereof.

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

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

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

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

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. 2A and 2B, the OLED display 100 includes a first electrode 220 and a first electrode 220 formed on a substrate 202, and includes an organic emission layer (EL) 234) and

A second electrode 240 formed on the organic layer and a second electrode 240 formed on the organic layer and including an electron transport layer (ETL) 236 made of a compound represented by the chemical formula (Not shown).

Wherein n is a natural number from 0 to 2, X is O, S or NR, and R, R ¹ , R ² , R ³ , L and Ar independently represent, 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 and containing at least one hetero atom selected from O, N, S, Si and P, A fused ring group of an aliphatic ring of 60 to 60 carbon atoms and an aromatic ring of 6 to 60 carbon atoms, an alkyl group of 1 to 50 carbon atoms, an alkenyl group of 2 to 20 carbon atoms, an alkynyl group of 2 to 20 carbon atoms, an alkoxyl group of 1 to 30 carbon atoms, Lt; / RTI > to 30 aryloxy groups.

Here, the organic layer 230 may include a hole transport layer (HTL) 232, an organic light emitting layer 234, and an electron transport layer 236 which are 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 emission method of the organic light emitting diode display 100 includes a top emission method in which the emission direction is the second electrode 240 direction in the organic layer 230 and a top emission method in which the organic layer 230 is oriented in the first electrode 220 direction (Bottom emission). In the present specification, the upper emission scheme has been mainly described for the convenience of description. However, it should be noted that the present invention is not limited thereto and can be applied to the bottom emission scheme.

First, the substrate 202 is not only a glass substrate, but also a plastic substrate including PET (Polyethylene terephthalate), PEN (Polyethylen naphthalate), and polyimide, etc., and ITO Tin Oxide), IZO (Indium Zinc Oxide), or the like.

Further, a buffer layer may be further provided on the substrate 202 to block penetration of impurity elements. 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, A gate electrode 204 formed of a plurality of layers, a gate insulating film 206 formed of an inorganic insulating material or an organic insulating material, an amorphous silicon or indium gallium zinc oxide (IGZO), a zinc tin oxide (ZTO) A semiconductor layer 208 including a source electrode and a drain electrode 210, and a semiconductor layer 208 including a source electrode and a drain electrode.

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

The first electrode 220 may be formed of a transparent conductive material such as a metal oxide such as ITO or IZO, a metal oxide such as ZnO: Al or SnO ₂ : Sb Such as a mixture of the same metal and an oxide, such as poly (3-methylthiophene), poly [3,4- (ethylene-1,2-dioxy) thiophene] (PEDT), polypyrrole and polyaniline Conductive polymer or the like. In addition, the first electrode 220 may include a carbon nano tube, graphine, silver nano wire, or the like.

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

The organic layer 230 may have a multilayer structure including a hole transport layer 232, an organic emission layer 234, and an electron transport layer 236, but 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 using a variety of polymer materials by a solvent process such as spin coating, dip coating, doctor blading, screen printing, inkjet printing, or thermal transfer (for example, Laser Induced Thermal Imaging (LITI)) or the like.

The highest occupied molecular orbital (HOMO) of the hole injecting material is a function between the work function of the anode material and the HOMO of the surrounding organic material layer have. Specific examples of the hole injecting material include organic materials such as metal porphyrine, oligothiophene, arylamine-based organic materials, hexanitrile, hexaazatriphenylene, quinacridone- , Perylene based organic materials, anthraquinone, and polyaniline and polythiophene based conductive polymers, but the present invention is not limited thereto.

A hole transport layer 232 may be formed on the hole injection layer. The hole transport layer 232 transports holes from the hole injection layer and transports holes to the organic light emitting layer 234 positioned thereon. The hole transport layer 232 has high hole mobility, stability to holes, and electrons. In addition to these general requirements, the heat resistance of the device is required when it is applied to a vehicle body. Examples of the material that satisfies such conditions include NPD, NPB, spiro-arylamine compounds, perylene-arylamine compounds, azacyclopentadienyl compounds, bis (diphenylvinylphenyl) anthracene, silicon germanium oxide compounds, (E.g., a silicon-based arylamine compound), a conductive polymer, a block copolymer having a conjugated portion and a non-conjugated portion together, but the present invention is not limited thereto.

The organic light emitting layer 234 is a layer in which holes and electrons injected from the anode and the cathode respectively recombine to emit light and are made of a material having a high quantum efficiency. As the light emitting material, a material capable of emitting light in the visible light region by transporting and combining holes and electrons from the hole transporting layer 232 and the electron transporting layer 236 is preferable, and a material having good quantum efficiency for fluorescence or phosphorescence is preferable .

Examples of the light-emitting substance or compound satisfying such conditions include 8-hydroxy-quinoline aluminum complex (Alq ₃ ), carbazole type compound; Dimerized styryl compounds, BAlq; (P-phenylenevinylene) (PPV) -based polymer, a spiro compound, a polyfluorene compound, a polybenzimidazole compound, Rubrene, and the like, but are not limited thereto.

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

For example, Alq ₃ is used as a green luminescent material, BAlq (8-hydroxyquinoline beryllium salt), DPVBi (4,4'-bis (2,2-diphenylethenyl) -1,1'- biphenyl) Spiro material, Spiro-4,4'-bis (2,2-diphenylethenyl) -1,1'-biphenyl, LiPBO (2- (2-benzoxazoyl) -phenol lithium salt) And metal complexes of imidazole, thiazole, and oxazole, and perylene and BczVBi (3,3 '[((4-hydroxyphenyl) 1,1'-biphenyl) -4,4'-diyldi-2,1-ethenediyl] bis (9-ethyl) -9H-carbazole; DSA (distrylamine). In the case of the red luminescent material, a green luminescent material is doped with 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). Polymer such as polyphenylene vinylene (PPV) -based polymer or polyfluorene when the organic light emitting layer 234 is formed using processes such as inkjet printing, roll coating, spin coating, (234).

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

On the organic light-emitting layer 234, the electron-transporting layer 236 is located. As such an electron transport layer 236, there is a need for a material capable of efficiently injecting electrons with high electron injection efficiency from the second electrode 240 positioned thereon. For this purpose, a material having a high electron affinity and high electron transfer rate and excellent stability against electrons is used. Specific examples of the electron transporting material satisfying such conditions include an Al complex of 8-hydroxyquinoline, a complex containing Alq3, an organic radical compound, and a hydroxyflavone-metal complex, but the present invention is not limited thereto.

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 one embodiment is, for example,

≪ / RTI > More specifically

≪ / RTI > In the formulas, n is a natural number of 0 to 2, X is O, S or NR, and R, L and Ar are independently of each other an aryl group having 6 to 60 carbon atoms, a heterocyclic group having 2 to 60 carbon atoms, A fused ring group of 3 to 60 aliphatic rings and an aromatic ring of 6 to 60 carbon atoms.

The electron transport layer 236 represented by the above chemical formula interacts with the passivation layer 250 to reduce the deterioration of the second electrode 240 and improve the injection characteristics of electrons, The life can be increased. This will be described in detail in connection with Figs. 3 to 7.

On the other hand, an electron injection layer may be stacked on the electron transport layer 236. The electron injection layer may be a metal complex compound such as Balq, Alq ₃ , Be (bq) ₂ , Zn (BTZ) ₂ , Zn (phq) ₂ , PBD, spiro-PBD, TPBI, Tf-6P, , But it is not limited thereto. [0041] The term " aromatic compound "

2B illustrates an organic layer 230 including a hole transport layer 232, an organic emission layer 234 and an electron transport layer 236 as an example. However, the organic layer 230 is not limited to the hole transport layer 232, the organic emission layer 234, A light emitting layer, a blocking layer, a light emitting auxiliary layer, a hole transporting auxiliary layer, or a buffer layer.

When the second electrode 240 formed on the organic layer 230 functions as a cathode electrode, the second electrode 240 may be formed of a metal material having a relatively low work function value, for example, aluminum (Al) And 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 described as a capping layer (CPL).

A conventional general passivation layer is made of an inorganic insulating material such as SiON, silicon nitride (SiNx), silicon oxide (SiOx), aluminum oxide (AlOx) or the like with hydrophobic properties in consideration of mechanical strength, moisture permeability, Or an organic insulating material including benzocyclobutene (BCB) and an acryl-based resin.

However, the passivation layer 250 according to embodiments may be formed of a semiconductor material and may include, for example, zinc (Zn) or antimony (Sb). More specifically, Semiconductor material or III-V compound semiconductor material. II-VI compound semiconducting materials can be used in a variety of applications including zinc oxide (ZnO), zinc sulphide (ZnS), zinc selenide (ZnSe), zinc telluride (ZnTe), cadmium sulphide , Cadmium Selenide (CdS) and Cadmium Telluride (CdTe), and the III-V compound semiconductor material is one of 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) But , But is not limited thereto.

The passivation layer 250 may be a film type, but is not limited thereto. By slowing the penetration of water or oxygen, the organic layer 230, which is sensitive to moisture and oxygen, can be prevented from coming into contact with moisture. Also, the passivation layer 250 may be formed of a single layer, but not limited thereto, and may be formed of multiple layers.

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

The thickness of the passivation layer 250 may be 300 ANGSTROM to 600 ANGSTROM, but is not limited thereto. When the thickness is less than 300 ANGSTROM, there is a problem in preventing penetration of moisture and oxygen. When the thickness is more than 600 ANGSTROM, the thickness of the OLED display 100 becomes thick, It may be difficult to apply.

The thickness of the organic layer 230 may be m / 2 times (where m is a natural number) the wavelength of the light emitted from the organic layer 230, but is not limited thereto. This can provide a microcavity effect that increases the efficiency of light emitted by the light reflected between the first electrode 220 and the second electrode 240 through destructive interference.

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 larger than the refractive index of the second electrode 240. This is to reduce the optical loss of the light emitted from the organic light emitting layer 234 toward the second electrode 240 to improve the efficiency of the OLED display 100.

3 is a view showing paths of light in the organic light emitting diode display according to the embodiments.

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

The refractive indices n ₁ to n ₄ and the thicknesses t ₁ and t ₃ are only for convenience of explanation and the organic light emitting diode display 100 according to the embodiments is not limited to this, As shown in FIG.

The refractive index n ₂ 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, the refractive index n ₄ of the air 360, Can be 1.0. At this time, according to Snell's law, when light passes from a medium having a small refractive index to a medium having a large refractive index, light may be collected.

More specifically, the light (L ₁₁₎ at the interface of the light emission in the organic emission layer 234 of the organic layer 230, the light beyond the critical angle (θ ₁₎ is the total reflection, of less than the critical angle (θ ₁₎ light (L ₁₂ Is transmitted to the second electrode 240 through the interface. At this time, when the thickness t ₁ of the organic layer 230 is m / 2 times the emission wavelength (where m is a natural number), the light L ₁₁ totally reflected by the above-mentioned micro cavity effect can be eliminated.

Since the refractive index n ₂ of the second electrode 240 is 0.2 and the refractive index n ₃ of the passivation layer 250 is 1.8, the refractive index n ₁ of the second electrode 240 is different from 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 as compared with the light L ₂ incident at the interface between the second electrode 240 and the passivation layer 250. Since in the passivation layer 250, the critical angle (θ ₃₎ to beyond the light (L ₃₁₎ is totally reflected, the total reflection light (L ₃₁₎ can be destroyed by the above-described micro-cavity effect, than the critical angle (θ ₃₎ The light L ₃₂ incident at a small angle is dispersed into the air 360. Meanwhile, the thickness t ₃ of the passivation layer 250 may be 300 Å to 600 Å.

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 deflected in the normal direction of the interface can be dispersed again to improve the viewing angle.

The organic light emitting diode display 100 can minimize dispersion of light and light loss due to total reflection according to the difference in refractive index, improve viewing angle, and increase light efficiency.

4 to 7 illustrate the effect of the organic light emitting diode display 100 according to the present invention in the case where the passivation layer 250 is formed of a semiconductor material and the electron transport layer 236 is formed of a specific compound Explain.

FIG. 4 is a graph showing a current vs. voltage of an OLED display according to an exemplary embodiment of the present invention and a conventional OLED display according to an exemplary embodiment of the present invention. FIG. FIG. 6 is a graph showing a comparison of life spans of an organic light emitting display according to an embodiment and a conventional organic light emitting display, and FIG. 6 7 is a graph showing a comparison of the lifetime of red, green, and blue elements of the organic light emitting display according to the embodiment and the conventional organic light emitting display.

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

Lt; 2 > However, this is for convenience of explanation, 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, an aryl group having 6 to 60 carbon atoms, a fluorene group, O, N, S, at least one of Si and P A fused ring group of 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, a heterocyclic group having 2 to 60 carbon atoms, 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.

In the case where 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, a larger amount of current can flow than in a 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 may be deteriorated or the electrical characteristics may be deteriorated. When the passivation layer 250 is formed of a semiconductor material and the electron transport layer 236 is formed of the compound described above, when electrons are supplied to the organic emission layer 234 through the electron transport layer 236, It becomes possible to lower the resistance value due to the conductivity and thus to prevent the deterioration or deterioration of the electrical characteristics. That is, the passivation layer 250 functions as a conductor to increase the thickness of the second electrode 240 and reduce the sheet resistance value.

Therefore, as shown in FIG. 5, the amount of current used as heat 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. Referring to FIG. 6, a is a general organic compound in which an electron transport layer (ETL_1) is formed, a passivation layer is also formed of a common organic compound, b is an organic compound, and an electron transport layer (ETL_1) Is formed of a semiconductor material, and c is a case where, according to an embodiment

(ETL_2) is formed of a compound expressed by the following chemical formula, and the passivation layer 250 is formed of a semiconductor material, and d is

(ETL_2) is formed of a compound represented by the chemical formula shown below, and the passivation layer is formed of a general organic compound. Also, FIG. 6 shows a graph when the second electrode 240 is made of an alloy of magnesium and silver, the refractive index of a passivation layer made of a general organic compound is 1.8, and the refractive index of a passivation layer made of a semiconductor material is 2.8.

A comparison of a and b reveals that the luminance efficiency increases from 4.7 cd / A to 5.5 cd / A, resulting in a slight increase in lifetime. On the other hand, when c and d are compared, the application of the electron transport layer 236 made of a specific compound and the passivation layer 250 made of a semiconductor material results in a high luminance efficiency over time and a relatively large lifetime can see.

This is because, as described above, the passivation layer 250 made of a semiconductor material becomes conductive, thereby preventing degradation 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, the lifetime of the red (R), blue (B), and green (G) light emitting devices constituting the organic light emitting layer 234 is shown. (a) is a graph when an electron transport layer 236 is formed of a general organic compound and a passivation layer is formed of a general organic compound. On the other hand, (b)

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

the lifetime of the red light emitting element R, the green light emitting element G and the blue light emitting element B among the blue light emitting elements B in the case of a general organic light emitting display device, The problem is solved by maximizing the aperture ratio of the blue light emitting element B and lowering the aperture ratio of the red light emitting element R and the green light emitting element.

On the other hand, in the case of (b), it can be seen that the lifetime of the blue light-emitting element B is the same as that of the other light-emitting elements R and G. This is because the conductive property of the passivation layer 250 prevents deterioration of the electrical characteristics of the OLED display 100 and the lifetime of the electron transport layer 236 made of the above compound improves the electron injection property .

8A to 8E are cross-sectional views illustrating a method of manufacturing an OLED display according to another embodiment of the present invention.

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 includes the steps of forming a first electrode 220 on a substrate 202, forming an organic emission layer on the first electrode 220, EL, 234) and

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

First, a transistor is formed on the substrate of the organic light emitting display device 100. [ The transistor including the gate electrode 204, the gate insulating film 206, the semiconductor layer 208, and the source / drain electrode 210 may be formed by physical vapor deposition (CVD) or chemical vapor deposition Deposited through a deposition process, and patterned through an etching process.

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

Meanwhile, a 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 may be formed of an organic material by a solution process.

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

8B to 8E illustrate the case where the organic layer 230 is composed of three layers of the hole transporting layer 232, the organic light emitting layer 234 and the electron transporting layer 236 for convenience of explanation, And the organic layer 230 of the OLED display 100 may be formed of various numbers 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 a part of the plurality of layers may be formed by a solution process.

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

A second electrode 240 is formed on the organic layer 230 over the entire surface of the organic light emitting display panel 140. 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 a 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 given above.

When a voltage is applied to the first electrode 220 and the second electrode 240 of the OLED display 100, since the passivation layer 250 has conductivity, the sheet resistance of the second electrode 240 is reduced The leakage current is prevented and deterioration of the second electrode 240 is prevented to increase reliability and lifetime of the OLED display 100. [

The refractive index of the passivation layer 250 is 1.8 to 3.6 and is greater than the refractive index of the second electrode 240. Therefore, it functions as an optical device and functions to increase the light efficiency through the refractive index difference.

Further, the passivation layer 250 may have a thickness of 300 ANGSTROM to 600 ANGSTROM, which improves the electron injection characteristics through interaction with the electron transport layer material, and increases the lifetime of the blue light emitting element B.

Meanwhile, forming the passivation layer 250 is a step of forming the passivation layer 250 by physical vapor deposition (CVD) or chemical vapor deposition (CVD).

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

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

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

Specifically, the thickness of the passivation layer 250 may not be uniform while the deposition process is performed. In addition, the particles may be stacked in a certain region and may be stacked in an island shape where the density of the particles is small in other regions . For example, in the case of a thermal deposition process, which is one of the physical chemical vapor deposition processes, after the material forming the passivation layer 250 is vaporized, the second electrode 240 is again solidified to be deposited on the second electrode 240, And thus an island shape may be formed or a bonding area at the bonding interface may not be sufficiently formed.

Such a defective bonding state promotes deterioration of the device and may shorten the life of the OLED display 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 100 at a temperature lower than the lowest glass transition temperature (Tg) of each of the compounds contained in the organic layer 230. That is, if 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 may change, resulting in a problem that the visibility and the luminance are lowered and the color reproduction rate is decreased , It is required to be a temperature lower than the glass transition temperature so as not to cause a change in the organic layer 230.

However, the bonding area between the second electrode 240 and the passivation layer 250 may be wider as the temperature for heating the organic light emitting display device 100 is higher. For example, if the lowest value among the respective glass transition temperature values of the materials contained in the organic layer 230 is 250 ° C, the interlayer interfacial bonding characteristics can be most improved when heated to a temperature close to 250 ° C have.

In other words, the heat treatment step has an effect of heating the organic light emitting display device 100 to dissolve the materials constituting the passivation layer 250 deposited at an uneven density and uniformly distribute the materials. In other words, the bonding area between the second electrode 240 and the passivation layer 250 is widened, the aggregated materials are dispersed, and the thickness uniformity occurs. Accordingly, the reliability of the OLED display 100 can be improved and the lifetime thereof can be prolonged. Here, the bonding area means an area where the second electrode 240 and the passivation layer 250 are in contact (or in close contact).

9A and 9B are tables and graphs comparing efficiency and lifetime of an OLED display according to an exemplary embodiment of the present invention and a conventional OLED display.

9A and 9B, Sample 1 corresponds to a general organic light emitting display and Sample 2 corresponds to an organic light emitting device including a passivation layer 250 made of zinc selenide (ZnSe) Sample 3 corresponds to the display device 100 and corresponds to the OLED display 100 including the passivation layer 250 made of zinc selenide (ZnSe) according to an embodiment.

On the other hand, the samples used the organic layer 230 emitting similar colors (refer to the color coordinates), and T95 in the table means the time taken for the life of the organic light emitting display 100 to reach 95%.

Referring to FIGS. 9A and 9B, the efficiency of Sample 2 (Sample 2) was higher (5.5 cd / A) and the lifetime (T95) was 60 hours longer than that of Sample 1 180 Hrs).

On the other hand, in the case of the sample 3 performed to the heat treatment step in the organic light emitting display device 100, the efficiency is the same as the sample 2 (Sample 2), but the lifetime T95 is remarkably increased (350 hrs). This is an effect that occurs due to the fact that internal elements including the organic layer 230 are protected from the external environment by improving bonding properties or contact characteristics between the second electrode 240 and the passivation layer 250 due to heat treatment.

In summary, the organic light emitting diode display 100 has a structure in which the passivation layer 250 made of a semiconductor material not only increases light efficiency through a difference in refractive index, but also has a conductive property when a voltage is applied to deteriorate the second electrode 240 Thereby improving the electrical characteristics. Further, the electron transport layer 236 made of a specific compound improves the electron injection characteristics, thereby increasing the lifetime of the blue light emitting device B, thereby increasing the lifetime of the OLED display 100 itself.

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

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

It is to be understood that the terms "comprises", "comprising", or "having" as used in the foregoing description mean that the constituent element can be implanted unless specifically stated to the contrary, But should be construed as further including other elements. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Commonly used terms, such as predefined terms, should be interpreted to be consistent with the contextual meanings of the related art, and are not to be construed as ideal or overly formal, unless expressly defined to the contrary.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

202: substrate 204: gate electrode
212: planarization layer 222:
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 located on a substrate;
An organic light emitting layer (EL)

An electron transport layer (ETL) composed of a compound represented by the following formula:
A second electrode located on the organic layer; And
And a passivation layer formed on the second electrode and made of a semiconductor material.
In the above formulas,
Wherein n is a natural number of 0 to 2, X is O, S or NR,
R, L, and Ar are independently selected from the group consisting 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 a fused ring group having 6 to 60 carbon atoms It is selected from the group. The method according to claim 1,
Wherein the semiconductor material comprises zinc (Zn) or antimony (Sb). The method according to claim 1,
Wherein the semiconductor material comprises a II-VI compound semiconductor material or a III-V compound semiconductor material,
The II-VI compound semiconductor material may be at least one selected from the group consisting of zinc oxide (ZnO), zinc sulfide (ZnS), zinc selenide (ZnSe), zinc telluride (ZnTe), cadmium sulfide Sulfide, CdS, Cadmium Selenide, and Cadmium Telluride,
The III-V compound semiconductor material may be at least one selected from the group consisting of Aluminum Phosphide (AlP), Aluminum Arsenide (AlAs), Aluminum Antimonide (AlSb), Gallium Nitride (GaN) Gallium phosphide (GaP), gallium arsenide (GaAs), gallium antimonide (GaSb), indium nitride (InN), indium phosphide (InP) Wherein the organic light emitting layer is one of indium arsenide (InAs), indium antimonide (InSb). The method according to claim 1,
Wherein the passivation layer has conductivity when electrons are supplied to the organic emission layer through the electron transport layer. The method according to claim 1,
And the refractive index of the passivation layer is 1.8 to 3.6. The method according to claim 1,
And the refractive index of the passivation layer is greater than the refractive index of the second electrode. The method according to claim 1,
Wherein the passivation layer has a thickness of 300 to 600 ANGSTROM. The method according to claim 1,
Wherein the organic layer comprises 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 the substrate;
On the first electrode, an organic emission layer (EL)

Forming an organic layer including an electron transport layer (ETL) composed of a compound represented by the general formula (1);
Forming a second electrode on the organic layer;
Forming a passivation layer of a semiconductor material on the second electrode; And
And a heat treatment step.
In the above formulas,
Wherein n is a natural number of 0 to 2, X is O, S or NR,
R, L, and Ar are independently selected from the group consisting 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 a fused ring group having 6 to 60 carbon atoms It is selected from the group. 10. The method of claim 9,
The forming of the passivation layer may include:
Wherein the passivation layer is formed by physical vapor deposition (CVD) or chemical vapor deposition (CVD). 10. The method of claim 9,
The heat treatment step may include:
Wherein the organic light emitting display device is heated at a temperature lower than a lowest glass transition temperature (Tg) of each of the compounds contained in the organic layer. 10. The method of claim 9,
In the heat treatment step,
Wherein the bonding area between the second electrode and the passivation layer is increased as the temperature for heating the organic light emitting display device is higher.

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