KR20170063054A - Organic light emitting device - Google Patents

Abstract

The organic light emitting device according to an embodiment of the present invention includes a first electrode, a second electrode, a first light emitting unit disposed between the first electrode and the second electrode, the first light emitting unit including a first organic light emitting layer, A second light emitting unit including a second organic light emitting layer, and a charge generating layer located between the first light emitting unit and the second light emitting unit, wherein the charge generating layer comprises a first region including a host and an n-type dopant, A second region including a host and a p-type dopant, and a third region located between the first region and the second region and made of a host.

Description

ORGANIC LIGHT EMITTING DEVICE

The present invention relates to an organic light emitting device, and more particularly, to an organic light emitting device capable of simplifying a process, improving lifetime, and minimizing a driving voltage rise in an organic light emitting device having a two stack structure.

The organic light emitting diode (OLED) is a self-luminous display device in which electrons and holes are injected into the light emitting layer from an anode for injecting electrons and an anode for injecting holes, And emits light when an exciton in which injected electrons and holes are coupled falls from an excited state to a ground state.

The organic light emitting display device includes a top emission type, a bottom emission type, and a dual emission type depending on a direction in which light is emitted, and a passive matrix type ) And active matrix (Active Matrix).

Unlike a liquid crystal display (LCD), an organic light emitting display does not require a separate light source, and can be manufactured in a light and thin shape. Further, the organic light emitting display device is not only advantageous from the viewpoint of power consumption by low voltage driving, but also excellent in color implementation, response speed, viewing angle, and contrast ratio (CR), and is being studied as a next generation display.

The number of pixels per unit area increases and a high luminance is required. However, since the unit area current (A) is limited by the light emitting structure of the organic light emitting display device, There is a problem that reliability is lowered and power consumption is increased.

Therefore, it is necessary to overcome the technical limitations of the luminous efficiency, life span, and power consumption reduction of the organic light emitting device, which are factors that hinder the quality and productivity of the organic light emitting diode display. And various organic light emitting devices capable of improving viewing angle characteristics have been studied.

A variety of organic light emitting device structures have been proposed for improving the efficiency, lifetime, and power consumption of an organic light emitting device in order to improve the performance, quality, and productivity of the organic light emitting display device.

Accordingly, a plurality of stacks may be formed to realize improved efficiency and lifetime characteristics as well as a single stacked organic light emitting device structure using one stack, that is, an electroluminescence unit (EL unit) , That is, a multi-stack structure using a stack of a plurality of light emitting units has been proposed.

Among stacked organic light emitting devices using a stack of a plurality of light emitting units, in the case of an organic light emitting device having a stack structure, a first organic light emitting layer included in a first light emitting unit having the same color, And a second organic emission layer included in the second organic emission layer are stacked twice with a charge generation layer (CGL) interposed therebetween.

That is, in the case of an organic light emitting device having a two stack structure, since the light emitting region where light is emitted through recombination of electrons and holes is located in each of the first light emitting unit and the second light emitting unit, The organic EL device can exhibit high efficiency compared to the light emitting device and can be driven at a low current, thereby improving the lifetime of the organic light emitting device.

The charge generation layer CGL is composed of two layers of an n-type charge generation layer (n-CGL) doped with an n-type dopant and a p-type charge generation layer (p-CGL) doped with a p-type dopant, The dopant material changes the Fermi level of the host material of the n-type charge generation layer and the host material of the p-type charge generation layer so that electrons and holes can easily move to each other.

The charge generation layer CGL may be formed by supplying holes and electrons to the respective organic light emitting layers in the second light emitting unit located on the upper portion of the charge generation layer CGL and the first light emitting unit located on the lower portion, And serves to form an exciton in the light emitting layer.

The n-type charge generation layer (n-CGL) and the p-type charge generation layer (p-CGL) are separately deposited in the conventional organic light emitting device having a two stack structure. And the process time is prolonged due to the movement between the deposition chambers and the host material and the dopant are used for the n-type charge generation layer (n-CGL) and the p-type charge generation layer (p-CGL) A problem occurs.

In addition, since the host material of the n-type charge generation layer (n-CGL) and the p-type charge generation layer (p-CGL) are different from each other in the conventional organic light emitting device having a stack structure, At the bonded interface, electrons and holes meet to form an exciton, which emits energy while returning to the original level, which can damage the organic material and degrade its properties.

In addition, since the resistance increases greatly at the interface between the n-type charge generation layer (n-CGL) and the p-type charge generation layer (p-CGL) and electrons and holes are not supplied to each light emitting unit, There has been a problem of decreasing the amount of water.

 Further, due to unstable interfacial properties due to excitons generated at the interface between the n-type charge generation layer (n-CGL) and the p-type charge generation layer (p-CGL) The driving voltage of the organic light emitting diode is greatly increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a two-stack organic light emitting device using two stacked light emitting units, which simplifies the process, And an organic electroluminescent device.

The solutions according to the embodiments of the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

In the organic light emitting device having the two stack structure using the stacking of two light emitting units according to the organic light emitting display according to the embodiment of the present invention, an organic light emitting device capable of simplifying the process, / RTI >

The organic light emitting device according to an embodiment of the present invention includes a first electrode, a second electrode, a first light emitting unit disposed between the first electrode and the second electrode, the first light emitting unit including a first organic light emitting layer, A second light emitting unit including a second organic light emitting layer, and a charge generating layer located between the first light emitting unit and the second light emitting unit, wherein the charge generating layer comprises a first region including a host and an n-type dopant, A second region including a host and a p-type dopant, and a third region located between the first region and the second region and made up of a host.

The LUMO (Lowest Unoccupied Molecular Orbital) energy level of the host may be between 2.8 eV and 3.5 eV, and the HOMO (Hightest Occupied Molecular Orbital) energy level may be between 5.3 eV and 6.5 eV.

The host may be any one selected from the group consisting of oxadiazole derivatives, anthracene derivatives, Alq3, PBD, TAZ, spiro-PBD, BAlq, and SAlq.

The n-type dopant may be composed of any one of an alkali metal, an alkaline earth metal, an alkali metal compound and an alkaline earth metal compound.

The LUMO (Lowest Unoccupied Molecular Orbital) energy level of the p-type dopant may be 4.3 eV to 6.7 eV, and the HOMO (Hightest Occupied Molecular Orbital) energy level may be 7 eV to 9.6 eV.

The p-type dopant may be any one of F ₄ -TCNQ and NDP-9.

The thickness of the charge generating layer may be from 200 ANGSTROM to 500 ANGSTROM.

The thickness of the third region may be between 5 and 15 Angstroms.

The second light emitting unit may be located above the first light emitting unit.

The organic light emitting device includes a red sub pixel region, a green sub pixel region, and a blue sub pixel region, wherein the first organic light emitting layer and the second organic light emitting layer include at least one of a red sub pixel region, a green sub pixel region, Lt; / RTI >

In another aspect, an organic light emitting device having a multi-stack structure including a plurality of light emitting units according to an embodiment of the present invention includes a host, a n-type dopant, and a p-type dopant And the charge generation layer includes an intermediate layer region composed of a host between a region including an n-type dopant and a region containing a p-type dopant, whereby an n-type charge generation layer and a p-type charge generation The reaction between electrons and holes generated at the interface between the layers is minimized, thereby improving the lifetime and minimizing the increase of the driving voltage.

The n-type dopant and the p-type dopant may be included only in the region of the charge generation layer excluding the intermediate layer region.

The thickness of the charge generating layer may be from 200 ANGSTROM to 500 ANGSTROM.

The thickness of the interlayer region may range from 5 to 15 Angstroms.

The charge generating layer may be made up of a single layer through a single deposition process.

In the case of an organic light emitting device having a multi-stack structure including a plurality of light emitting units according to an embodiment of the present invention, a charge generating layer located between a plurality of light emitting units is formed by a single deposition process, a host, an n-type dopant, And a single layer including a dopant, the manufacturing process of the organic light emitting device can be simplified, and the material cost can be reduced.

In the case of an organic light emitting device having a multi-stack structure including a plurality of light emitting units according to an embodiment of the present invention, a charge generation layer composed of a single layer is formed between a region including an n-type dopant and a region including a p- The reaction between electrons and holes generated at the interface between the n-type charge generation layer and the p-type charge generation layer is minimized, so that the lifetime of the organic light emitting device is improved and the driving voltage The occurrence of the phenomenon can be minimized.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the following description.

The scope of the claims is not limited by the matters described in the contents of the invention, as the contents of the invention described in the problems, the solutions to the problems and the effects to be solved do not specify essential features of the claims.

1 is a schematic cross-sectional view of an organic light emitting diode according to an embodiment of the present invention.
2 is a cross-sectional view of a charge generation layer of an organic light emitting device according to an embodiment of the present invention.
3 is a graph showing energy levels of a charge generation layer of an organic light emitting device according to an embodiment of the present invention.
4 is a schematic view illustrating a method of forming a charge generating layer of an organic light emitting device according to an embodiment of the present invention.
FIG. 5 is a graph showing a life evaluation result of an organic light emitting device according to a comparative example and an embodiment of the present invention.
FIGS. 6A to 6C are graphs showing experimental results of driving voltage change after storage at high temperature for each dopant doping condition of an organic light emitting device according to a comparative example. FIG.
FIGS. 7A to 7C are graphs showing experimental results of driving voltage change after storage at high temperature for each dopant doping condition of an organic light emitting diode according to an embodiment of the present invention. FIG.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

The shapes, sizes, ratios, angles, numbers, and the like disclosed in the drawings for describing the embodiments of the present invention are illustrative, and thus the present invention is not limited thereto. Like reference numerals refer to like elements throughout the specification. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Where the terms "comprises", "having", "done", and the like are used in this specification, other portions may be added unless "only" is used. Unless the context clearly dictates otherwise, including the plural unless the context clearly dictates otherwise.

In interpreting the constituent elements, it is construed to include the error range even if there is no separate description. In the case of a description of the positional relationship, for example, if the positional relationship between two parts is described as 'on', 'on top', 'under', and 'next to' Or " direct " is not used, one or more other portions may be located between the two portions.

Also, the first, second, etc. are used to describe various components, but these components are not limited by these terms. These terms are used only to distinguish one component from another. Therefore, the first component mentioned below may be the second component within the technical spirit of the present invention.

It is to be understood that each of the features of the various embodiments of the present invention may be combined or combined with each other, partially or wholly, technically various interlocking and driving, and that the embodiments may be practiced independently of each other, It is possible.

Hereinafter, the organic light emitting device of the present invention will be described in detail with reference to the drawings.

1 is a schematic cross-sectional view of an organic light emitting diode according to an embodiment of the present invention.

1, an organic light emitting device 1000 according to an exemplary embodiment of the present invention includes a substrate on which a red subpixel region Rp, a green subpixel region Gp, and a blue subpixel region Bp are defined a first electrode (110, anode) is formed with a hole injection layer (120, hole injection layer: HIL), a first hole transport layer (130, 1 ^st hole transporting layer: 1 ^st HTL), the first red light emitting layer (140, 1 consisting of ^{1 st blue EML): st Red} emission layer: 1 st Red EML), a first green light-emitting layer ^{(141, 1 st green emission layer} : 1 st green EML) and the first blue light emitting layer (142, 1 ^st blue emission layer the first organic light emitting layer, a first electron transport layer ^{(150, 1 st electron transporting layer} : 1 st ETL), the charge generating layer (160, charge generation layer: CGL ), a second hole transport layer ^{(170, 2 nd hole transporting layer} : 2 ^nd HTL), the second red light emitting layer ^{(180, 2 nd red emission layer} : 2 nd red EML), a second green light-emitting layer ^{(181, 2 nd green emission layer} : 2 nd green EML) and the second blue light emitting Layer ^{(182, 2 nd Blue emission layer} : 2 nd Blue EML) a second organic light emitting layer, a second electron transport layer formed of a ^{(190, 2 nd electron transporting layer} : 2 nd ETL), a second electrode (200, cathode) and the cap And a capping layer 210 (CPL).

1, an organic light emitting diode 1000 according to an exemplary embodiment of the present invention includes a first light emitting unit 1100 including a first organic light emitting layer between a first electrode 110 and a second electrode 200 , 1 ^st EL unit) and a second organic light emitting device of claim 2, the light emitting unit (1200, 2 ^nd EL unit) is laminated with a second stack (stack) structure configured to include an organic light emitting layer.

More specifically, the first light emitting unit 1100 of the organic light emitting diode 1000 according to the embodiment of the present invention includes a hole injection layer 120, a first hole transport layer 130, a first red light emitting layer 140, 1 green light emitting layer 141 and a first blue light emitting layer 142, and a first electron transporting layer 150. The first organic light emitting layer 141 and the first blue light emitting layer 142 may be formed of the same material.

The second light emitting unit 1200 of the organic light emitting diode 1000 according to the exemplary embodiment of the present invention includes a second hole transport layer 170, a second red light emitting layer 180, a second green light emitting layer 181, A second organic light emitting layer made of a light emitting layer 182, and a second electron transporting layer 190.

The organic light emitting device 1000 according to an embodiment of the present invention includes a charge generation layer 160 positioned between the first light emitting unit 1100 and the second light emitting unit 1200.

Although not shown, an organic light emitting display device including an organic light emitting diode according to an exemplary embodiment of the present invention includes a gate line and a data line crossing each other and defining pixel regions, and a power source And a switching thin film transistor connected to the gate wiring and the data wiring and a driving thin film transistor connected to the switching thin film transistor are disposed in each pixel region. The driving thin film transistor is electrically connected to the first electrode 110 (anode).

The first electrode 110 is disposed on the substrate so as to correspond to each of the red subpixel region Rp, the green subpixel region Gp, and the blue subpixel region Bp, and may be a reflective electrode. For example, the first electrode 110 may include a transparent conductive material layer having a high work function such as indium-tin-oxide (ITO) and a reflective layer such as a silver (Ag) Material layer.

The hole injection layer 120 Is located on the first electrode 110 so as to correspond to both the red subpixel region Rp, the green subpixel region Gp, and the blue subpixel region Bp.

The hole injection layer 120 may function to smooth the injection of holes and may be formed of HATCN (1,4,5,8,9,11-hexaazatriphenylene-hexanitrile), CuPc (cupper phthalocyanine), PEDOT (poly , 4) -ethylenedioxythiophene, PANI (polyaniline) and NPD (N, N-dinaphthyl-N, N'-diphenylbenzidine).

The first hole transport layer 130 and the second hole transport layer 170 are formed to correspond to both the red subpixel region Rp, the green subpixel region Gp, and the blue subpixel region Bp, The transport layer 130 is located on the hole injection layer 120 and the second hole transport layer 170 is located on the second charge generation layer 165.

The first hole transporting layer 130 and the second hole transporting layer 170 serve to smooth the transport of holes and may be made of NPD (N-dinaphthyl-N, N'-diphenylbenzidine), TPD (N, bis- (3-methylphenyl) -N, N'-bis- (phenyl) -benzidine, s-TAD and MTDATA (4,4 ' -triphenylamine), but the present invention is not limited thereto.

1, the first red light emitting layer 140 of the first light emitting unit 1100 is located in the red sub pixel region Rp on the first hole transporting layer 130, The second red light emitting layer 180 is located in the red subpixel region Rp on the second hole transporting layer 170. The first red light emitting layer 140 and the second red light emitting layer 180 may each include a light emitting material that emits red light, and the light emitting material may be formed using a phosphor or a fluorescent material.

More specifically, the first red luminescent layer 140 and the second red luminescent layer 180 may be formed of CBP (4,4'-bis (carbozol-9-yl) biphenyl) or mCP (1,3-bis (N-carbozolyl) benzene ), And any one selected from the group consisting of PQIr (acac) (bis (1-phenylquinoline) acetylacetonate iridium), PQIr (tris (1-phenylquinoline) iridium) and PtOEP (octaethylporphyrin platinum) (DBM) 3 (Phen) or Perylene. However, the present invention is not limited to these phosphors.

1, the first green light emitting layer 141 of the first light emitting unit 1100 is located in the green sub pixel region Gp on the first hole transporting layer 130, and the second light emitting unit 1200, The second green light emitting layer 181 is located in the green sub pixel region Gp on the second hole transporting layer 170. [ The first green light emitting layer 141 and the second green light emitting layer 181 may include a light emitting material that emits green light, and the light emitting material may be formed using a phosphor or a fluorescent material.

More specifically, the first green light emitting layer 141 and the second green light emitting layer 181 may include a host material including CBP or mCP and include Ir (ppy) ₃ (fac tris (2-phenylpyridine) iridium) iridium complexes and be formed of a phosphorescence material including a dopant material, such as (Ir complex) that, by contrast, be formed of a fluorescent material containing a different _{Alq 3 (tris (8-hydroxyquinolino} ) aluminum) , but not limited to these.

1, the first blue light emitting layer 142 of the first light emitting unit 1100 is located in the blue sub pixel area Bp on the first hole transporting layer 130, The second blue light emitting layer 182 of the second hole transporting layer 170 is located in the blue sub pixel region Bp on the second hole transporting layer 170. The first blue light emitting layer 142 and the second blue light emitting layer 182 may include a light emitting material that emits blue light, and the light emitting material may be formed using a phosphor or a fluorescent material.

More specifically, the first blue light emitting layer 142 and the second blue light emitting layer 182 may include a host material including CBP or mCP, and may include a phosphorescent material containing a dopant material including (4,6-F2ppy) 2Irpic ≪ / RTI > The fluorescent material may include any one selected from the group consisting of spiro-DPVBi, spiro-6P, distyrylbenzene (DSB), distyrylarylene (DSA), PFO polymer and PPV polymer. It does not.

The organic light emitting device 1000 according to an embodiment of the present invention includes a red sub pixel region Rp, a green sub pixel region Gp, and a blue sub pixel region Bp, 2 organic light emitting layer may be located in at least one of the red sub pixel region Rp, the green sub pixel region Gp, and the blue sub pixel region Bp.

1, the first electron transport layer 150 includes a first red light emitting layer 140 and a second red light emitting layer 140 so as to correspond to both the red subpixel region Rp, the green subpixel region Gp, and the blue subpixel region Bp. 1 green light emitting layer 141 and the first blue light emitting layer 142 and the second electron transporting layer 190 is located on the red sub pixel region Rp, the green sub pixel region Gp, and the blue sub pixel region Bp, The second red light emitting layer 180, the second green light emitting layer 181, and the second blue light emitting layer 182 so as to correspond to all of the red,

The first electron transport layer 150 and the second electron transport layer 190 may serve as transport and injection electrons and the first electron transport layer 150 and the second electron transport layer 190 may have electron transport properties . ≪ / RTI >

The first electron transporting layer 150 and the second electron transporting layer 190 serve to smooth the transport of electrons and include Alq ₃ (tris (8-hydroxyquinolino) aluminum), PBD (2- (4-biphenylyl) -5 - (4-tert-butylpheny) -1,3,4oxadiazole), TAZ, spiro-PBD, BAlq and SAlq.

Although not shown in FIG. 1, an electron injection layer (EIL) may be separately formed on the second electron transport layer 190.

The electron injection layer (EIL) is composed of Alq ₃ (tris (8-hydroxyquinolino) aluminum), PBD (2- (4-biphenylyl) -5- PBD, BAlq, or SAlq.

Here, the structure is not limited according to the embodiment of the present invention, and the structure of the hole injection layer 120, the first hole transport layer 130, the second hole transport layer 170, the first electron transport layer 150, At least one of the electron transport layer 190 and the electron injection layer (EIL) may be omitted. At least one of the first hole transport layer 130, the second hole transport layer 170, the first electron transport layer 150, the second electron transport layer 190, and the electron injection layer (EIL) .

The charge generation layer 160 of the organic light emitting device 1000 according to the exemplary embodiment of the present invention may include a charge generation layer 160 such that the charge generation layer 160 may correspond to both the red subpixel region Rp, the green subpixel region Gp, and the blue subpixel region Bp. And is positioned on the electron transporting layer 150.

1, the charge generating layer 160 is located between the first light emitting unit 1100 and the second light emitting unit 1200, and the charge generating layer 160 is disposed between the first light emitting unit 1100 and the second light emitting unit 1200. [ And controls the charge balance between the two light emitting units of the two light emitting units 1200.

1, the charge generating layer 160 of the organic light emitting device 1000 according to an exemplary embodiment of the present invention may be formed as a single layer through a single deposition process. Referring to FIG. 1, a first region 161 including a host and an n-type dopant, a second region 163 including a host and a p-type dopant and a first region 161, And a third region 162 that is located between the second regions 163 and does not include an n-type dopant and a p-type dopant and is a host.

That is, the first region 161 of the charge generation layer 160 of the organic light emitting device 1000 according to the embodiment of the present invention is a first light emitting unit 1100 located below the charge generation layer 160, (N-CGL) for helping the charge generation layer 160 to emit light, and the second region 163 of the charge generation layer 160 can serve as an n-type charge generation layer (n-CGL) 1200) to serve as a p-type charge generation layer (p-CGL) for injecting holes.

The second electrode 200 is positioned on the second electron transport layer 190 to correspond to both the red subpixel region Rp, the green subpixel region Gp, and the blue subpixel region Bp. For example, the second electrode 200 may be made of an alloy of magnesium and silver (Mg: Ag) and may have a transflective property. That is, the light emitted from the organic light emitting layer is displayed to the outside through the second electrode 200. Since the second electrode 200 has the transflective property, some of the light is directed to the first electrode 110 again .

The first electrode 110 and the second electrode 200 are formed by a micro-cavity effect in which repetitive reflection occurs between the first electrode 110 and the second electrode 200 serving as a reflective layer, The light is repeatedly reflected in the cavity between the light source and the light source, thereby increasing the light efficiency.

In addition, the first electrode 110 may be formed as a transmissive electrode, the second electrode 200 may be formed as a reflective electrode, and light emitted from the organic emission layer may be displayed externally through the first electrode 110 .

The capping layer 210 is located on the second electrode 200. The capping layer 210 may serve to increase the light extracting effect in the organic light emitting device and may include the first hole transporting layer 130 and the second hole transporting layer 170 material, the first electron transporting layer 150, The first red light emitting layer 140 and the second red light emitting layer 180 and the first green light emitting layer 141 and the second green light emitting layer 181, the first blue light emitting layer 142, and the second And the host material of the blue light emitting layer 182. Further, the capping layer 210 can be omitted.

2 is a cross-sectional view of a charge generation layer of an organic light emitting device according to an embodiment of the present invention.

3 is a graph showing energy levels of a charge generating layer of an organic light emitting device according to an embodiment of the present invention.

In the conventional organic light emitting device having a two stack structure, the charge generation layer (CGL) includes an n-type charge generation layer (n-CGL) doped with an n-type dopant and a p-type charge generation layer (p-CGL), and the charge generation layer CGL is formed in the second light emitting unit located above the charge generation layer CGL and the first light emitting unit located below the charge generation layer CGL, To each of the organic light emitting layers to form an exciton in the organic light emitting layer of each light emitting unit.

That is, in the conventional organic light emitting device having a two stack structure, the n-type charge generation layer (n-CGL) and the p-type charge generation layer (p-CGL) are separately deposited. (N-CGL) and the p-type charge generation layer (p-CGL), respectively, because the host material and the dopant are used. .

In addition, since the host material of the n-type charge generation layer (n-CGL) and the p-type charge generation layer (p-CGL) are different from each other in the conventional organic light emitting device having a stack structure, At the bonded interface, electrons and holes meet to form an exciton, which emits energy while returning to the original level, which can damage the organic material and degrade its properties.

In addition, since the resistance increases greatly at the interface between the n-type charge generation layer (n-CGL) and the p-type charge generation layer (p-CGL) and electrons and holes are not supplied to each light emitting unit, There has been a problem of decreasing the amount of water.

 Further, due to unstable interfacial properties due to excitons generated at the interface between the n-type charge generation layer (n-CGL) and the p-type charge generation layer (p-CGL) The driving voltage of the organic light emitting diode is greatly increased.

In order to solve the above problems, the charge generating layer 160 of the organic light emitting device 1000 according to the embodiment of the present invention includes an n-type charge generation layer (n-CGL) and a p-type charge generation layer (p-CGL ) And an intermediate layer region made of a host between the region including the n-type dopant in the charge generating layer 160 and the region containing the p-type dopant .

2, the charge generating layer 160 of the organic light emitting device according to the exemplary embodiment of the present invention may be formed as a single layer through a single deposition process, a first region 161 including an n-type host and an n-type dopant, a second region 163 including a host and a p-type dopant and a first region 161, And a third region 162, which is located between the first region 163 and the second region 163 and does not include an n-type dopant and a p-type dopant and is a host.

A first region 161 including an n-type dopant and a host of the charge generation layer 160 and a second region 163 including a host and a p-type dopant By changing the Fermi level of the host material of the charge generation layer 160 in each region, electrons and holes can easily move to each other.

That is, the first region 161 of the charge generation layer 160 of the organic light emitting device 1000 according to the embodiment of the present invention is a first light emitting unit 1100 located below the charge generation layer 160, (N-CGL) for helping the charge generation layer 160 to emit light, and the second region 163 of the charge generation layer 160 can serve as an n-type charge generation layer (n-CGL) 1200) to serve as a p-type charge generation layer (p-CGL) for injecting holes.

3, the LUMO (Lowest Unoccupied Molecular Orbital) energy level of the host of the charge generating layer 160 of the organic light emitting device 1000 according to the embodiment of the present invention is 2.8 eV to 3.5 eV, and HOMO (Hightest Occupied Molecular Orbital) energy level may be 5.3 eV to 6.5 eV.

The host of the charge generation layer 160 may be at least one selected from the group consisting of an oxadiazole derivative, an anthracene derivative, Alq3, PBD, TAZ, spiro-PBD, BAlq and SAlq.

The n-type dopant included in the host of the first region 161 of the charge generation layer 160 may be composed of any one of alkali metal, alkaline earth metal, alkali metal compound and alkaline earth metal compound.

Also, the LUMO (Lowest Unoccupied Molecular Orbital) energy level of the p-type dopant contained in the host of the second region 163 of the charge generation layer 160 is 4.3 eV to 6.7 eV and the HOMO (Highest Occupied Molecular Orbital ) Energy level may be between 7 eV and 9.6 eV.

The p-type dopant included in the host of the second region 163 of the charge generation layer 160 may be any one of F ₄ -TCNQ and NDP-9.

Further, the thickness of the charge generating layer 160 may be in the range of 200 ANGSTROM to 500 ANGSTROM, which is a level capable of operating as a charge generation layer.

The organic light emitting device 1000 according to an embodiment of the present invention may include a first region 161 and a second region 163 and may include an n-type dopant and a p-type dopant, the third region 162, which is a buffer layer, can minimize the reaction of electrons and holes that may occur at the interface formed between the n-type charge generation layer and the p-type charge generation layer.

The thickness of the third region 162 of the charge generation layer 160 of the organic light emitting device 1000 according to the exemplary embodiment of the present invention is set to be a thickness of the intermediate layer that can minimize the reaction of electrons and holes in the charge generation layer 160 layer, it may preferably be from 5 to 15 Angstroms.

That is, in the case of the organic light emitting device having a multi-stack structure including a plurality of light emitting units according to an embodiment of the present invention, the charge generation layer composed of a single layer may include a region including the n-type dopant and the p- And the interface between the n-type charge generation layer and the p-type charge generation layer, it is possible to minimize the reaction of electrons and holes generated at the interface between the n-type charge generation layer and the p-type charge generation layer to improve the lifetime of the organic light emitting device, The occurrence of the driving voltage rise phenomenon can be minimized.

4 is a schematic view illustrating a method of forming a charge generating layer of an organic light emitting device according to an embodiment of the present invention.

Referring to FIG. 4, the charge generation layer (CGL) of the organic light emitting device according to the embodiment of the present invention may be formed as a single layer through a single deposition process in one organic deposition chamber.

4, an organic deposition chamber for forming a charge generating layer (CGL) of an organic light emitting diode according to an embodiment of the present invention includes an n-dopant deposition source, a host deposition chamber Source and a source for doping the p-type dopant (n-dopant).

In general, a substrate is deposited while moving in both directions in an organic deposition chamber. In the case of an organic light emitting device according to an embodiment of the present invention, a substrate is moved in one direction in the organic deposition chamber, And the substrate can be recovered and deposited only when moving in one direction.

That is, as shown in FIG. 4, in the organic deposition chamber, a substrate is opposed to an n-type dopant source, a host source, and a p-type dopant source, The first region including the host and the n-type dopant, the first region including the n-type dopant and the p-type dopant in the organic light emitting element on the substrate, and the intermediate region consisting only of the host, a third region that is a buffer layer and a second region that includes a host and a p-type dopant may be sequentially formed.

A charge generation layer (CGL) according to an embodiment of the present invention having a single layer and having an intermediate layer region may be formed through the single deposition process as described above. In the case of the third region as the intermediate layer, The thickness of the host deposited on the intermediate layer can be changed by adjusting the angle regulating plate provided therein.

That is, in the case of an organic light emitting device having a multi-stack structure including a plurality of light emitting units according to an embodiment of the present invention, the charge generation layer located between the plurality of light emitting units may be formed by a single deposition process, And a p-type dopant, the manufacturing process of the organic light emitting device can be simplified, and the material cost can be reduced by reducing the kinds of materials used in the charge generation layer (CGL).

FIG. 5 is a graph showing a life evaluation result of an organic light emitting device according to a comparative example and an embodiment of the present invention.

More specifically, FIG. 5 shows a case where the charge generation layer (CGL) is a n-type charge generation layer (n-CGL) doped with an n-type dopant and a p-type charge generation layer A two-stack organic light emitting device having a conventional structure composed of two layers, and a charge generation layer (CGL) formed of a single layer, and a region between the region including the n-type dopant and the region containing the p- And the lifetime characteristics of the organic light emitting device according to the embodiment of the present invention including the intermediate layer region are compared and evaluated.

Referring to FIG. 5, in the comparative example, the lifetime characteristic, which is the time from the initial luminance to the luminance of 95% of the initial luminance, was about 250 hours. In the organic light emitting device according to the embodiment of the present invention, , The lifetime characteristic is about 350 hours. In the case of including an intermediate layer region comprising a host between a region containing an n-type dopant and a region containing a p-type dopant, Can be seen.

That is, in the case of the organic light emitting device having a multi-stack structure including a plurality of light emitting units according to an embodiment of the present invention, the charge generation layer composed of a single layer may include a region including the n-type dopant and the p- The present invention can minimize the reaction of electrons and holes generated at the interface between the n-type charge generation layer and the p-type charge generation layer, and can prevent electrons and holes from reaching the first light emitting unit and the second The lifetime of the organic light emitting element can be improved by sufficiently transmitting the light to each of the light emitting units.

FIGS. 6A to 6C are graphs showing experimental results of driving voltage change after storage at high temperature for each dopant doping condition of an organic light emitting device according to a comparative example. FIG.

7A to 7C are graphs showing experimental results of driving voltage change after storage at high temperature for each dopant doping condition of an organic light emitting diode according to an embodiment of the present invention.

6A to 6C are cross-sectional views illustrating a method of manufacturing a charge generation layer (CGL) according to another embodiment of the present invention. Referring to FIGS. 6A to 6C, the charge generation layer CGL is formed of an n-type charge generation layer (n-CGL) doped with an n-type dopant and a p- CGL), a change in the driving voltage required for achieving luminance of 700 nits after high temperature storage in a high temperature chamber of 95 deg. C for 96 hours and 240 hours, The results of the evaluation are shown.

6A, 6B and 6C, the concentration of the p-type dopant contained in the p-type charge generation layer (p-CGL) was varied to 12%, 24% and 36% The results are shown in Fig.

7A to 7C are cross-sectional views of the present invention in which the charge generation layer (CGL) is composed of one layer and an intermediate layer region composed of a host between a region containing an n-type dopant and a region containing the p- The results of evaluating a change in driving voltage required for achieving a luminance of 700 nit after a high temperature storage in a 95 ° C high temperature chamber for 96 hours and 240 hours in the blue organic light emitting device according to the embodiment.

In the case of FIGS. 7A, 7B and 7C, the concentration of the p-type dopant included in the second region of the charge generation layer (CGL) was varied to 12%, 24%, and 36% The results are shown in Fig.

Referring to FIG. 6A, in the case of Comparative Example 1 in which the concentration of the p-type dopant (p-dopant) was applied to the level of 12%, the driving voltage was maintained at 0.2 V for 240 hours, Respectively.

On the other hand, referring to FIG. 7A, in the case of Embodiment 1 in which the concentration of the p-type dopant is applied to the level of 12%, 0.12 V after 96 hours of high temperature storage, . As a result, it can be seen that the driving voltage increase level during driving after high-temperature storage under the condition 1 of the embodiment is decreased compared to the comparative example condition 1 under the same p-type dopant application condition.

Next, referring to FIG. 6B, in the case of Comparative Example 2 in which the concentration of the p-type dopant (p-dopant) was applied to the level of 24%, the device was driven at a high voltage of 0.9V And the voltage was increased.

On the other hand, referring to FIG. 7B, in the case of the embodiment 2 in which the concentration of the p-type dopant was 24%, the driving voltage was maintained at 0.12 V for 240 hours, . It can be seen that the driving voltage increase level during driving after the storage at high temperature in the condition 2 of Example 2 compared with Comparative Example 2 under the application of the same p-type dopant is decreased.

Referring to FIG. 6C, in the case of Comparative Example 3 in which the concentration of the p-type dopant was 36%, the driving voltage was maintained at 1.2V for 240 hours, Respectively.

On the other hand, referring to FIG. 7C, in the case of Example 3 in which the concentration of the p-type dopant was applied to the level of 36%, the driving voltage was maintained at 0.2V after being kept at a high temperature for 96 hours, . It can be seen that the driving voltage increase level during driving after the high temperature storage under the condition 3 of Example 3 compared with Comparative Example 3 under the same p type dopant application condition is decreased.

In the case of the organic light emitting device having a multi-stack structure including a plurality of light emitting units according to an embodiment of the present invention, the charge generation layer located between the plurality of light emitting units may be formed by a single deposition process, , an n-type dopant, and a p-type dopant, the manufacturing process of the organic light emitting device can be simplified and the material cost can be reduced.

In the case of an organic light emitting device having a multi-stack structure including a plurality of light emitting units according to an embodiment of the present invention, a charge generation layer composed of a single layer is formed between a region including the n-type dopant and a region including the p- , It is possible to minimize the reaction of electrons and holes generated at the interface between the n-type charge generation layer and the p-type charge generation layer to improve the lifetime of the organic light emitting device, The occurrence of the voltage rising phenomenon can be minimized.

In the present specification, in the case of a charge generating layer composed of a single layer including an intermediate layer region composed of a host between a region including an n-type dopant and a region containing a p-type dopant through evaluation of a blue organic light emitting element having a two- The present invention is not limited to the red organic light emitting device and the green organic light emitting device in the same manner as the blue organic light emitting device according to the embodiment of the present invention, , The lifetime of the organic light emitting device is improved, and the occurrence of the driving voltage rise phenomenon at the time of driving after storage at a high temperature is minimized.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, have. 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. Therefore, it should be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of protection of the present invention should be construed according to the claims, and all technical ideas within the scope of equivalents should be interpreted as being included in the scope of the present invention.

1000: organic light emitting element
110: first electrode
120: Hole injection layer
130: First hole transport layer
140: first red light emitting layer
141: first green light emitting layer
142: first blue light emitting layer
150: first electron transporting layer
160: charge generation layer
170: Second hole transport layer
180: second red light emitting layer
181: second green light emitting layer
182: second blue light emitting layer
190: Second electron transport layer
200: second electrode
210: capping layer
1100: first light emitting unit
1200: second light emitting unit
Rp: Red sub pixel area
Gp: green sub pixel area
Bp: blue sub pixel area

Claims (15)

A first electrode and a second electrode;
A first light emitting unit located between the first electrode and the second electrode, the first light emitting unit including a first organic light emitting layer;
A second light emitting unit located between the first electrode and the second electrode, the second light emitting unit including a second organic light emitting layer; And
And a charge generation layer disposed between the first light emitting unit and the second light emitting unit,
The charge generation layer may include a first region including a host and an n-type dopant, a second region including the host and the p-type dopant, and a third region formed between the first region and the second region, .
The method according to claim 1,
Wherein a Lowest Unoccupied Molecular Orbital (LUMO) energy level of the host is between 2.8 eV and 3.5 eV, and a Hightest Occupied Molecular Orbital (HOMO) energy level is between 5.3 eV and 6.5 eV.
3. The method of claim 2,
Wherein the host comprises at least one selected from the group consisting of an oxadiazole derivative, an anthracene derivative, Alq3, PBD, TAZ, spiro-PBD, BAlq and SAlq.
The method according to claim 1,
Wherein the n-type dopant comprises any one of an alkali metal, an alkaline earth metal, an alkali metal compound and an alkaline earth metal compound.
The method according to claim 1,
The LUMO (Lowest Unoccupied Molecular Orbital) energy level of the p-type dopant is 4.3 eV to 6.7 eV, and the HOMO (Hightest Occupied Molecular Orbital) energy level is 7 eV to 9.6 eV.
6. The method of claim 5,
Wherein the p-type dopant comprises any one of F ₄ -TCNQ and NDP-9.
The method according to claim 1,
Wherein the charge generation layer has a thickness of 200 ANGSTROM to 500 ANGSTROM.
8. The method of claim 7,
And the third region has a thickness of 5 ANGSTROM to 15 ANGSTROM.
The method according to claim 1,
And the second light emitting unit is located above the first light emitting unit.
The method according to claim 1,
The organic light emitting device includes a red sub pixel region, a green sub pixel region, and a blue sub pixel region,
Wherein the first organic light emitting layer and the second organic light emitting layer are located in at least one of the red sub pixel region, the green sub pixel region, and the blue sub pixel region.
In an organic light emitting device having a multi-stack structure including a plurality of light emitting units,
Wherein the charge generation layer located between the plurality of light emitting units is formed of a single layer including a host, an n-type dopant and a p-type dopant, and the charge generation layer includes a region including the n-type dopant and the p- The intermediate layer region made up of the host between the regions including the dopant minimizes the reaction of electrons and holes generated at the interface between the n-type charge generation layer and the p-type charge generation layer, This minimized organic light emitting device.
12. The method of claim 11,
Wherein the n-type dopant and the p-type dopant are contained only in a region of the charge generation layer excluding the intermediate layer region.
12. The method of claim 11,
Wherein the charge generation layer has a thickness of 200 ANGSTROM to 500 ANGSTROM.
14. The method of claim 13,
Wherein the thickness of the intermediate layer region is 5 to 15 ANGSTROM.
12. The method of claim 11,
Wherein the charge generation layer comprises a single layer through a single deposition process.

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