KR101573762B1 - Double-sided organic light-emitting diode and display device and illumination - Google Patents

Abstract

A transparent upper electrode on the substrate, a transparent upper electrode facing the lower electrode, an organic layer interposed between the lower electrode and the upper electrode, the organic layer including a light emitting layer, a first light extraction enhancement layer on the upper electrode, Layer on the substrate, a second light extraction enhancement layer on the substrate opposite to the lower electrode, a first antireflection layer on the first light extraction enhancement layer, and a second antireflection layer on the second light extraction enhancement layer, An organic electroluminescent device is provided.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-sided light emitting organic light emitting diode (OLED), a display device including the same,

And more particularly, to a double-sided emission type organic light emitting device having improved outcoupling efficiency and a method of manufacturing the same.

An organic light emitting diode (OLED) is a self-luminous type device having a wide viewing angle, excellent contrast, fast response time, excellent luminance, driving voltage and response speed characteristics, and multicolorization.

The organic light emitting element is composed of an organic layer including a light emitting layer between the anode and the cathode. When a voltage is applied between the anode and the cathode of the organic light emitting diode, holes injected from the anode and electrons injected from the cathode are recombined in the light emitting layer to generate excitons, and the excitons emit light while being changed from the excited state to the ground state.

A double-sided light emitting type organic light emitting element is an organic light emitting element in which light is emitted in both directions on the front and back sides of the element. The double-sided emission type organic light-emitting device has a relatively weak resonance effect as compared with the front emission type or backside emission type device in which light is emitted to one side, and thus it is difficult to obtain high light extraction efficiency.

In general organic light emitting devices, the light extraction efficiency is limited to about 20% due to the total reflection due to the difference in the refractive index of the inner layer. In particular, an organic light emitting device using a transparent electrode such as ITO has a high light extraction efficiency Even lower. To improve this, layers for light extraction enhancement are introduced, but further improved light extraction efficiency is required.

And to provide a double-side emission type organic light emitting device having improved light extraction efficiency.

A transparent upper electrode on the substrate, a transparent upper electrode facing the lower electrode, an organic layer interposed between the lower electrode and the upper electrode, the organic layer including a light emitting layer, a first light extraction enhancement layer on the upper electrode, Layer on the substrate, a second light extraction enhancement layer on the substrate opposite to the lower electrode, a first antireflection layer on the first light extraction enhancement layer, and a second antireflection layer on the second light extraction enhancement layer, An organic electroluminescent device is provided.

At this time, the first antireflection layer and the second antireflection layer may be composed of a single layer or a plurality of layers of a material having a refractive index of 1.2 to 2.5.

The single layer and each of the layers constituting the plurality of layers may have a thickness of 30 nm to 200 nm.

When the first antireflection layer or the second antireflection layer comprises a plurality of layers, the plurality of layers include a low refractive index layer having a refractive index of 1.20 or more and less than 1.65 and a high refractive index layer having a refractive index of 1.65 or more and less than 2.50 . At this time, the low refractive index layer and the high refractive index layer may be alternately positioned.

The first anti-reflection layer and the second anti-reflection layer are, independently of each other _{LiF, MgF 2, CeF 3,} CaF 2, ScF 3, SiO 2, ITO, IZO, IGZO, TiO 2, SnO 2, ZnO, ZrO 2, Al ₂ O _3, and Ta ₂ O ₅ .

The first light extraction enhancement layer may include an array of a plurality of first convex portions having an inclination of 50 ° to 80 ° and a height of 50-100 μm. The first convex portion may have a conical shape, a polygonal pyramid shape, or a shape in which the upper surface thereof is cut off.

The second light extraction enhancement layer may include an array of a plurality of second convex portions. The second convex portion may have a conical shape, a pillar shape, a pyramid shape, or a lens shape.

The organic layer may include an n-doped layer, a light emitting layer on the n-doped layer, a hole transport layer on the light emitting layer, and a hole injection layer formed on the hole transport layer and made of a cyano group-containing compound. Alternatively, the organic layer may include an n-doped layer, an electron transport layer on the n-doped layer, a luminescent layer on the electron transport layer, a hole transport layer on the luminescent layer, and a hole injection layer formed on the hole transport layer and made of a cyano group- have.

Wherein the n-doped layer comprises a first electron transport material and at least one dopant selected from the group consisting of Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Cs ₂ CO ₃ , Rb ₂ CO ₃ , Ba ₂ CO ₃ , Pyronin B, DMC (decamethylcobaltocene), BEDTTTF (bis (ethylenedithio) -tetrathiafulvalene, bis (ethylenedithio) -tetrathiafulvalene), rhodamine B, TMBI (1,2,3-trimethyl-2-phenyl-2,3-dihydro-1H-benzoimidazole, 1,2,3-trimethyl- DMBI (1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzoimidazole, 1,3-dimethyl- dichlorophenyl-1,3-dimethyl-2,3-dihydro-1H-benzoimidazole, dichlorophenyl-1,3-dimethyl-2,3-dihydro-1H- benzoimidazole), N-DMBI (4- 3-dimethyl-2,3-dihydro-1H-benzoimidazole-2-yl) -phenyl) -dimethylamine, 4- -Yl) -phenyl) -dimethyl-amine), OH-DMBI (2- (1,3-dimethyl-2,3- dihydro-lH- benzoimidazol- phenol, 2- (1,3-dimethyl-2,3-dihydro-1H-benzoimidazol-2-yl) -phenol), PTCDI-C13 (N, N'-ditridecylperylene- -tetracarboxylic acid diimide, N, N'-ditridecylphenylene-3,4: 9,10-tetracarboxylic diimide) or F-PTCDI-C4 (N, N'-dibutyl-1,7-difluoroperylene -3,4: 9,10-tetracarboxylic acid diimide, N, N'-dibutyl-1,7-difluoroperylene-3,4: 9,10-tetracarboxylic acid diimide) . ≪ / RTI >

The n- doping layer is _{Li 2 CO 3, Na 2 CO} 3, K 2 CO 3, Cs 2 CO 3, Rb 2 CO 3, Ba 2 CO 3, non-B blood, DMC, BEDTTTF, rhodamine B, TMBI, A first electron transporting layer comprising an impurity layer made of at least one of DMBI, Cl-DMBI, N-DMBI, OH-DMBI, PTCDI-C13 or F- . ≪ / RTI >

The cyano group-containing compound may be hexaazatriphenylene hexacarbonitrile (HAT-CN).

The first light extraction enhancement layer and the second light extraction enhancement layer may independently have refractive indices of 1.4 to 2.2.

According to another aspect, there is provided a display device including the double-sided emission type organic light emitting device.

According to another aspect, there is provided an illumination including the double-sided emission type organic light emitting device.

In the double-sided emission type organic light emitting device, external quantum efficiency and power efficiency are improved by applying an antireflection layer on the light extraction enhancement layer.

1 is a cross-sectional view schematically showing a double-side emission type organic light emitting device according to one embodiment.
2 is a cross-sectional view schematically showing the structure of a double-side emission type organic light emitting device according to another embodiment.
3 is a graph showing the transmittance of the sample 1 and the sample 2 measured.
4 is a graph showing the ratio of the external quantum efficiency of the organic light emitting devices of Experimental Example 13 and Experimental Example 16 to the external quantum efficiency of the organic light emitting devices of Experimental Example 10 according to height of the microlens array.
5 is a graph showing the ratio of the external quantum efficiency of the OLEDs of Experimental Example 14 and Experimental Example 17 to the external quantum efficiency of the OLEDs of Experimental Example 11 according to the height of the microlens array.
6 is a graph showing the ratio of the external quantum efficiency of the organic light emitting devices of Experimental Example 15 and Experimental Example 18 to the external quantum efficiency of the organic light emitting devices of Experimental Example 12 according to the height of the microlens array.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are provided so that the disclosure can be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. In the drawings, like reference numerals refer to like elements.

1 is a cross-sectional view schematically showing a double-sided emission type organic light-emitting device 100 according to one embodiment.

A double-sided light emitting organic light emitting device 100 according to an embodiment includes a substrate 101, a transparent lower electrode 110 on the substrate 101, a transparent upper electrode 130 facing the lower electrode 110, An organic layer 120 interposed between the lower electrode 110 and the upper electrode 130, a first light extraction enhancement layer 141 on the upper electrode 130, and a second light extraction enhancement layer And a second antireflection layer 152 on the first antireflection layer 151 and the second light extraction enhancement layer 142 on the first light extraction enhancement layer 141. The first antireflection layer 142 is formed on the first light extraction enhancement layer 141,

The organic layer 120 includes an n-doped layer 123, a light emitting layer 125 formed on the n-doped layer 123, a hole transport layer 126 formed on the light emitting layer 125, and a hole transport layer 126 And a hole injection layer 127 made of a cyano group-containing compound.

The n-doped layer 123 is a layer containing an n-dopant as an impurity in a layer having an electron transporting property. When a voltage is applied to the device, electrons are generated in the n-doped layer 123, and electrons generated in the n-doped layer 123 are injected and transported into the light emitting layer 125.

The hole transport layer 126 and the hole injection layer 127 inject and transport holes into the light emitting layer 125. That is, the holes are injected from the upper electrode 130, and are transported to the light emitting layer 125 through the hole injection layer 127 and the hole transport layer 126 in order.

The first light extraction enhancement layer 141 may be formed to have a refractive index similar to that of the upper electrode 130 because it is formed on the upper electrode 130 for top emission. The first light extraction enhancement layer 141 may have a refractive index of about 1.4 to about 2.2.

The second light extraction enhancement layer 142 may be formed under the substrate 101 for bottom emission and may have a refractive index similar to that of the substrate 101. The second light extraction enhancement layer 142 may have a refractive index of about 1.4 to about 2.2.

The antireflection layers 151 and 152 are layers for preventing total internal total reflection of light at the interface between the light extraction enhancement layers 141 and 142 when light is transmitted through the light extraction enhancement layers 141 and 142 into the air. The first antireflection layer 151 and the second antireflection layer 152 may be made of a material having a refractive index lower than that of the first light extraction enhancement layer 141 and the second light extraction enhancement layer 142, . When the first antireflection layer 151 and the second antireflection layer 152 are formed of a plurality of layers, the low refraction layer and the high refraction layer may alternately exist. In this case, the low refractive index layer may have a refractive index of 1.20 or more and less than 1.65, and the high refractive index layer may have a refractive index of 1.65 or more and less than 2.5.

Generally, when a lower electrode is selected as a transparent electrode in a double-side emission type organic light emitting device, difficulties may arise in charge injection and transport due to a difference in work function. However, even when the lower electrode 110 is selected as the transparent electrode, the double-side emission type organic light emitting diode 100 of the present embodiment can smoothly inject and transport electrons, as described below.

Doped layer 123 is provided between the lower electrode 110 and the light emitting layer 125 in the double-sided light emitting organic light emitting device 100, so that the material selection of the lower electrode 110 can be widened. That is, when a negative voltage is applied to the lower electrode 110 and a positive electrode is applied to the upper electrode 130, the energy barrier at the interface between the n-doped layer 123 and the lower electrode 110 is lowered, Electrons can be easily injected and transported irrespective of the work function value of the electrode 110. As a result, the selection width of the lower electrode 110 of the device is widened, and the lower electrode 110 can be selected as a transparent electrode suitable for both-side light emission.

The n-doped layer 123 may be a single layer comprising an n-dopant in the first electron transporting material. A first electron transport material B3PYMPM (4,6-bis (3,5-di-3-pyridyl) -2-methylpyrimidine), Alq _3, Bphen (4,7- diphenyl -1, Diphenyl-1,10-phenanthroline), TPBi (2,2 ', 2 "- (1,3,5-benzenetri (1-phenyl-1H-benzimidazole), TPQ1 (tris-phenylquinoxalines 1,3,5-tris [(3-phenyl-6-trifluoromethyl) quinoxalin- ] Benzene), TPQ2 (tris-phenylquinoxalines 1,3,5-tris [{3- (4-tert- butylphenyl) -6-trifluoromethyl} quinoxalin- (4-phenyl-5-tert-butylphenyl-1,2,4-triazole), NTAZ (4- (naphthalen- 4H-1,2,4-triazole), tBu-PBD (2- (4-biphenylyl) -5- (4- tert- butylphenyl) -1,3,4- oxadiazole), BeBq ₂ (10-benzo [h] quinolinol-beryllium), E3 (terfuranene), or two or more of them.

Examples of the n-dopant include lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, At least one metal selected from the group consisting of La, Ce, Ne, Sm, Eu, Terbium, Dysprosium, A nitride of the metal; A carbonate of the metal; Or a complex of the metal may be used, but the present invention is not limited thereto. (Ba), lanthanum (La), cerium (Cs), magnesium (Mg), calcium (Ca), strontium (Sr), barium Since cerium (Ce), neodymium (Nd), samarium (Sm), europium (Eu), terbium (Tb), dysprosium (Dy) and ytterbium (Yb) have a relatively low work function, - can be used as a dopant. For example, at least one of Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Cs ₂ CO ₃ , Rb ₂ CO ₃ or Ba ₂ CO ₃ can be used as an n-dopant. On the other hand, pyronin B, DMC (decamethylcobaltocene), BEDTTTF (bis (ethylenedithio) -tetrathiafulvalene, bis (ethylene dithio) -tetrathiafulvalene), rhodamine B, , 1,2,3-trimethyl-2-phenyl-2,3-dihydro-1H-benzoimidazole, TMBI (1,2,3-trimethyl- , DMBI (1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzoimidazole and 1,3-dimethyl- (dichlorophenyl-1,3-dimethyl-2,3-dihydro-1H-benzoimidazole, dichlorophenyl-1,3-dimethyl-2,3-dihydro-1H- benzoimidazole), N-DMBI Dimethyl-2,3-dihydro-1H-benzoimidazole-2-yl) -phenyl) -dimethylamine, 4- (1,3- 2-yl) -phenyl) -dimethyl-amine), OH-DMBI (2- (1,3- N, N'-ditridecylperylene-3,4: 9,10-tetracarboxylic acid diimide, N, N'-dimethyl-2,3-dihydro-1H- benzoimidazol- Tetradecarboxylic acid diimide) or F-PTCDI-C4 (N, N'-dibutyl-1,7-difluoroperylene-3,4: 9, Type organic compound such as 10-tetracarboxylic acid diimide, N, N'-dibutyl-1,7-difluoroperylene-3,4: 9,10-tetracarboxylic acid diimide) It can be used as a dopant.

In this case, the content of the n-dopant may be 0.1 wt% to 25 wt% with respect to the total weight of the n-doped layer 123. When the n-dopant content satisfies the above range, electrons can be generated in a satisfactory level in the n-doped layer 123.

The n-doped layer 123 may be a single layer as described above. Alternatively, the n-doped layer 123 may be a single layer, as shown in FIG. 1, and an impurity layer 123 'made of n-dopant and a first The energy barrier at the interface between the impurity layer 123 'and the lower electrode 110 is lowered and the electron barrier layer 123' As a result, the selection width of the lower electrode 110 of the device is widened and the lower electrode 110 can be selected as a transparent electrode suitable for both-side light emission.

A hole injection layer 127 made of a cyano group-containing compound is provided under the upper electrode 130 of the double-sided emission type organic light emitting diode 100. The hole injection layer 127 not only smoothly injects and transports the holes injected from the upper electrode 130 into the light emitting layer 125 but also prevents damage to the organic layer that may occur in a manufacturing process such as sputtering. Due to the characteristics of the hole injection layer 127, the upper electrode 130 of the device can be selected as a transparent electrode suitable for both-side light emission.

The hole injection layer 127 is preferably used as a layer made of a single material which is not doped. When a layer made of a single material is used, it is possible to have a satisfactory level of hole injecting property without a substantial increase in drive voltage and to prevent damage to the organic layer.

As the material of the hole injection layer 127, a crystalline organic compound containing a cyano group may be used. As such a cyano group-containing crystalline organic compound, for example, hexaazatriphenylene hexacarbonitrile (HAT -CN).

        HAT-CN

Generally, when a transparent electrode is used for the upper electrode, it is difficult to inject and transport charges. However, when the hole injection layer 127 is formed using hexaazatriphenylene hexacarbonitrile (HAT-CN), an organic layer And has a lattice-like property to protect the organic layer from ion bombardment damage which may occur in a manufacturing process such as sputtering, thereby facilitating implementation of a transparent device.

A hole transport layer 126 is provided under the hole injection layer 127 of the double-sided emission type organic light emitting device 100. The hole transport layer 126 functions to smoothly inject and transport holes together with the hole injection layer 127.

The hole transporting layer 126 includes a hole transporting material. Examples of the hole transporting material include a phthalocyanine derivative, NPB (4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl), TPD (4,4'- ) -N-phenylamino] biphenyl), MTDATA (4,4 ', 4 "-tris [(3-methylphenyl) phenylamino] triphenylamine, TAPC (1,1- Phenyl) cyclohexane), TCTA (4- (9H-carbazol-9-yl) -N, N- -Benzenamine), CBP (9,9 '- [1,1'-biphenyl] -4,4'-diyl bis-9H-carbazole), mCP (9,9' (4,4 ', 4 "-tris (N- (2-naphthyl) -N-phenylamino) triphenylamine) or 2-TNATA But is not limited thereto.

A first light extracting enhancement layer 141 is formed on the upper electrode 130 of the double-sided light emitting organic light emitting device 100.

As the first light extracting enhancement layer 141, an organic material, an inorganic material, or a mixture thereof, which satisfies the refractive index of about 1.4 to about 2.2, may be used. The refractive index of the upper electrode 130 is higher than the refractive index of the lower substrate 101 so that the first light extraction enhancement layer 141 formed on the upper electrode 130 has a refractive index Can be higher.

The first light extraction enhancement layer 141 may have a visible light transmittance of about 70% to about 99%. The first light extraction enhancement layer 141 may be formed in contact with the upper electrode 130. The surface of the first light extraction enhancement layer 141 that is in contact with the upper electrode 130 is defined as a first incident surface and the surface located on the opposite side of the first incident surface is defined as a first exit surface, A plurality of first convex portions may be formed on the first emitting surface.

The first convex portion causes light scattering to improve extraction efficiency of light emitted from the light emitting layer 125 through the upper electrode 130 to the outside. Specifically, if the repetition period of the first convex portion is formed to be the wavelength region of the visible light, the first convex portion serves as a scattering body with respect to the visible light emitted through the upper electrode 130, thereby improving the extraction characteristic of visible light. The shape and period of the first convex portion are adjusted to be suitable for the scattering of the monochromatic wavelength because the light scattering pattern is determined according to the specific shape and the period of the first convex portion so that the extraction characteristic of the light emitted to the outside of the upper electrode 130 can be controlled.

The fill factor of the first convex portion is defined as a value obtained by dividing the surface area of the plurality of first convex portions formed on the first incident surface by the surface area of the first exit surface, and the fill factor of the first convex portion is about 50% In the case of about 100%, the scattering by the first convex portion is suitable, and the light extraction characteristic can be satisfactory.

The first convex portion may have a shape with a side slope such as a cone shape, a polygonal horn shape such as a triangular or quadrangular pyramid, or a shape in which the upper face thereof is cut off. The diameter D of the bottom surface of the first convex portion may be 1 to 500 mu m and the inclination angle [theta] with respect to the bottom surface of the first convex portion side may be about 50 to 80 [deg.]. The fill factor may be about 50% to 100%. When the first convex portion has the shape, the diameter, the inclination angle, and the fill factor as described above, it is possible to reduce the light loss due to the total reflection or the optical waveguide, and to extract the light more externally.

Under the substrate 101, a second light extracting enhancement layer 142 is provided. As the material of the second light extracting enhancement layer 142, an organic material, an inorganic material, or a mixture thereof, which satisfies the refractive index of about 1.4 to about 2.2, may be used. Since the second light extracting enhancement layer 142 is formed under the substrate 101, a material having a refractive index similar to that of the substrate 101 can be used. In the case of an organic material, a material having a low refractive index is generally used, and in the case of an inorganic material, a material having a high refractive index is mainly used. The visible light transmittance of the second light extraction enhancement layer 142 may be from about 70% to about 99%.

The second light extracting enhancement layer 142 may be in contact with the substrate 101. A surface of the second light extraction enhancement layer 142 that is in contact with the substrate 101 is defined as a second incident surface and a surface located on the opposite side of the second incident surface is defined as a second exit surface, A plurality of second convex portions may be formed on the second emitting surface.

The second convex portion causes light scattering to improve extraction efficiency of light emitted from the light emitting layer 125 through the substrate 101 to the outside. Specifically, if the repetition period of the second convex portion is formed to be the wavelength region of the visible light, the second convex portion can act as a scattering body with respect to visible light emitted through the substrate 101, thereby improving the extraction characteristic of visible light. The light scattering shape is determined according to the specific shape and the period of the second convex portion, so that the shape and period of the second convex portion can be adjusted to the scattering of the monochromatic light wavelength, so that the extraction characteristic of the light emitted to the outside of the substrate 101 can be controlled.

As a factor for specifying the shape and period of the second convex portion, a fill factor can be exemplified. The fill factor is defined as a value obtained by dividing the surface area of the plurality of second convex portions formed on the second incident surface by the surface area of the second exit surface. When the fill factor is about 50% to about 100%, scattering by the second convex portion is suitable, and the light extraction characteristic can be satisfactory.

The second convex portion may have a conical shape, a pillar shape, a pyramidal shape, or a lens shape. When the second convex portion has such a shape as described above, it is possible to reduce light loss due to total reflection or optical waveguide and to extract light more externally.

The width and height of the second convex portion can be changed according to the shape of the second convex portion and the wavelength of the scattered light. For example, the second convexity may be in the form of a lens, in which case the diameter and height of the underside of the second convexity may be between 1 and 500 microns, and the fill factor may be between about 70 and 90%.

The first antireflection layer 151 is formed on the first light extraction enhancement layer 141 and the second antireflection layer 152 is formed on the second light extraction enhancement layer 142. The first antireflection layer 151 and the second antireflection layer 152 may have a thickness of 30 nm to 200 nm independently of each other. The first antireflection layer and the second antireflection layer may independently be a material having a refractive index of 1.2 to 2.5 and may be a single layer or a plurality of layers.

When the first antireflection layer and the second antireflection layer are made of a single layer, the refractive index of the single layer may be 1.2 to 1.7 or 1.2 to 1.6 or 1.2 to 1.5. When the first antireflection layer and the second antireflection layer are composed of a plurality of layers, the plurality of layers may alternately have a layer having a low refractive index and a layer having a high refractive index. For example, in the case of three or more layers, the refractive index of the layer between the two layers may be smaller than the refractive index of the two layers, or the refractive index of the layer between the two layers may be larger than the refractive index of the two layers. At this time, the layer having a low refractive index may have a refractive index of, for example, 1.20 or more and less than 1.65, and the layer having a high refractive index may have a refractive index of 1.65 or more and less than 2.5, for example.

When the first antireflection layer and the second antireflection layer have a refractive index and a thickness in the above range, the first light extraction enhancement layer and the second light extraction layer of light emitted from the first light extraction enhancement layer and the second light extraction enhancement layer into the air, The total internal reflection at the boundary of the enhancement layer can be efficiently reduced, and the light extraction efficiency can be increased.

A first anti-reflection layer 151 and the second anti-reflection layer 152, for example, independently selected from _{LiF, MgF 2, CeF 3,} CaF 2, ScF 3, SiO 2, ITO, IZO, IGZO, TiO 2, SnO another _{2 , ZnO, ZrO 2, Al 2} O 3 Or a single layer of Ta ₂ O ₅ or a mixed layer thereof. For example, the first antireflection layer 151 and the second antireflection layer 152 may be formed of a single layer of LiF. When the first antireflection layer 151 and the second antireflection layer 152 are composed of a plurality of layers, the plurality of layers may alternately have the low refractive index layer and the high refractive index layer alternately. Here, the low refractive index layer may have a refractive index of 1.20 or more and less than 1.65, and the high refractive index layer may have a refractive index of 1.65 or more and less than 2.50. For example, the plurality of layers may comprise a double layer of MgF ₂ (n = 1.38) and Al ₂ O ₃ (n = 1.69) or MgF ₂ (n = 1.38), ZrO ₂ (n = 2.05) and Al ₂ O ₃ = 1.69). ≪ / RTI > The thickness of each layer constituting the plurality of layers may be 30 nm to 200 nm. Therefore, the total thickness of the mixed layer is the sum of the thicknesses of these layers.

2 is a cross-sectional view schematically showing the structure of a double-sided emission type organic light-emitting device 200 according to another embodiment.

The double-sided light emitting organic light emitting device 200 includes a substrate 101, a transparent lower electrode 110 formed on the substrate 101, and a transparent electrode 110 formed on the lower electrode 110 and opposed to the lower electrode 110 A transparent upper electrode 130, an organic layer 220 interposed between the lower electrode 110 and the upper electrode 130, a first light extraction enhancement layer 141 formed on the upper electrode 130, A second light extraction enhancement layer 142 formed under the first light extraction enhancement layer 141 and a second antireflection layer 152 on the first light extraction enhancement layer 151 and the second light extraction enhancement layer 142 on the first light extraction enhancement layer 141, ).

The organic layer 220 includes an n-doped layer 123, a light emitting layer 125 formed on the n-doped layer 123, a hole transport layer 126 formed on the light emitting layer 125, and a hole transport layer 126 formed on the n- And a hole injection layer 127 made of a cyano group-containing compound. A second electron transport layer 224 is further formed between the light emitting layer 125 and the n-doped layer 123 to facilitate injection and transportation of electrons.

The organic light emitting device 200 of this embodiment differs from the embodiment of FIG. 1 in that the organic layer 220 further includes a second electron transport layer 224.

And the second electron transporting layer 224 comprises a second electron transporting material. A second electron transport material is, like the first electron transport material B3PYMPM (4,6-bis (3,5-di-3-pyridyl) _{-2-methylpyrimidine), Alq 3, Bphen (4} , 1, 10-phenanthroline), BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), TPBi (2,2 ', 2 " , 3,5-benzenetriyl) -tris (1-phenyl-1H-benzimidazole), TPQ1 (tris-phenylquinoxalines 1,3,5-tris [ ) Quinoxalin-2-yl] benzene), TPQ2 (tris-phenylquinoxalines 1,3,5-tris [{3- (4- tert- butylphenyl) -6- trifluoromethyl} quinoxalin- (Benzene), TAZ (3- (4-biphenylyl) -4-phenyl-5-tert- butylphenyl-1,2,4- triazole), NTAZ (4- (naphthalen- -4,5-diphenyl-4H-1,2,4-triazole), tBu-PBD (2- (4-biphenylyl) -5- (Oxadiazole), BeBq ₂ (10-benzo [h] quinolinol-beryllium), E3 (terfuranene), or two or more of them.

Hereinafter, the structure and manufacturing method of the double-sided emission type organic light emitting device 200 will be described in detail with reference to the double-sided emission type organic light emitting device 200 shown in FIG. Meanwhile, the method of manufacturing the double-sided emission type organic light-emitting device 200 can be applied to the manufacture of the double-sided emission type organic light-emitting device 100.

A double-sided light emitting organic light emitting device 200 according to an embodiment includes a substrate 101, a transparent lower electrode 110 formed on the substrate 101, forming an organic layer 220 including an n-doped layer 123, a light emitting layer 125, a hole transporting layer 126 and a hole injection layer 127 made of a cyano group-containing compound; Forming an upper electrode 130 on the upper electrode 130, forming a first light extraction enhancement layer 141 having a refractive index of 1.4 to 2.2 on the upper electrode 130 and forming a first light extraction enhancement layer 141 having a refractive index of 1.4 to 2.2 The second light extracting enhancement layer 142 having the second light extraction enhancement layer 142 is formed.

As the substrate 101, a glass substrate or a transparent plastic substrate excellent in mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and waterproofness can be used, and in particular, a transparent substrate can be used for light emission on both sides.

For example, as the substrate 101, a transparent glass substrate having SiO ₂ as a main component can be used.

A lower electrode 110 is formed on the substrate. The lower electrode 110 is electrically connected to the drain electrode of the n-type thin film transistor through a via hole, and receives the driving current applied from the n-type thin film transistor. The lower electrode 110 may be, for example, a cathode.

The lower electrode 110 may be formed using a transparent material such as ITO (indium tin oxide), IZO (indium zinc oxide) or ZnO (zinc oxide), a transparent oxide such as a thin film graphene, Ag or Al . Preferably, ITO or the like can be used, and if necessary, ultraviolet-ozone-treated ITO may be used. The lower electrode 110 may be formed using various known methods, for example, a vapor deposition method, a sputtering method, a spin coating method, or a blade coating method.

An n-doped layer 123 is formed on the lower electrode 110. The n-doped layer 123 may be formed of a single layer doped with an n-dopant, which is an impurity, in the first electron transporting material, or may include a first electron transporting material in an impurity layer 123 ' And a first electron transporting layer 123 "are sequentially stacked.

In the n-doped layer 123, electrons are generated due to the influence of the n-dopant, and the generated electrons move toward the light emitting layer 125 through the electron transporting layer 274 to flow a current to the device.

The n-doped layer 123 may be formed by doping an n-dopant to the first electron transporting material. The doping concentration of the n-dopant may be about 0.1 wt% to 25 wt% Lt; / RTI > The n-doped layer 123 may be formed by various methods such as a vacuum deposition method, a spin coating method, a casting method, or an LB method. The thickness of the n-doped layer 123 may be between about 5 A and about 1,000 A thick. When the thickness of the n-doped layer 123 satisfies the above range, electrons can be generated to a satisfactory level in the n-doped layer 123 without a substantial increase in driving voltage.

When the n-doped layer is formed as a double layer, the impurity layer 123 'and the first electron transporting layer 123' are sequentially stacked by various methods such as a vacuum evaporation method, a spin coating method, a casting method, or an LB method And the thickness of the impurity layer 123 'may be about 2 A to about 100 A and the sum of the thicknesses of the impurity layer 123' and the first electron transporting layer 123 " may be about 5 A to about 1,000 A . If the thicknesses of the impurity layer 123 'and the first electron transporting layer 123' are within the above range, the impurity layer 123 'and the first electron transporting layer 123' Electrons can be generated.

The second electron transport layer 224 may be formed on the n-doped layer 123. The second electron transport layer 224 is formed using a second electron transport material, for example, B3PYMPM (bis-4,6- (3,5-di-3-pyridylphenyl) , Alq ₃ , Bphen (4,7-diphenyl-1,10-phenanthroline), BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), TPBi Tris (1-phenyl-1H-benzimidazole), TPQ1 (tris-phenylquinoxalines 1,3,5-tris [3- 2-yl] benzene), TPQ2 (tris-phenylquinoxalines 1,3,5-tris [{3- (4- tert- butylphenyl) -6-tri 4-phenyl-5-tert-butylphenyl-1,2,4-triazole), NTAZ (4-phenylphenyl) - (naphthalen-1-yl) -3,5-diphenyl-4H-1,2,4-triazole), tBu-PBD Phenyl) -1,3,4-oxadiazole), BeBq ₂ (10-benzo [h] quinolinol-beryllium), E3 (terfuranene), or mixtures of two or more thereof. The second electron The thickness of the second electron transporting layer 224 may be about 5 A to about 1,000 A. The thickness of the second electron transporting layer 224 may be about 2 A to about 1,000 A, When the thickness of the electron transporting layer 224 satisfies the above range, satisfactory electron injection and transportation characteristics can be obtained without increasing the driving voltage substantially.

A light emitting layer 125 is formed on the second electron transporting layer 224. The light emitting layer 125 can be formed using a known phosphorescent host and a phosphorescent dopant, or a known fluorescent host and a fluorescent dopant.

As known hosts, for example, Alq ₃ (tris (8-quinolinolato) aluminum), CBP (4,4'-N, N'-dicarbazole-biphenyl), ADN (9,10- Naphthalene-2-yl-anthracene), PVK (poly (n-vinylcarbazole)), TCTA, TPBI (1,3,5-tris (N-phenylbenzimidazol- (Tert-butyl-9,10-di (naphth-2-yl) anthracene), E3 or the like can be used.

As the red dopant, PtOEP (Pt (II) octaethylporphine), Ir (piq) ₃ (tris (2-phenylisoquinoline) iridium), Btp ₂ Ir (acac) ) - pyridinato-N, C3 ') iridium (acetylacetonate)), DCM (4- (dicyanomethylene) -2-methyl- 6- [p- (dimethylamino) Tetramethylurilidyl-9-enyl) -4H-pyran) or the like can be used. However, it is possible to use DCJTB (4- (dicyanomethylene) But is not limited thereto.

Ir (ppy) ₃ (tris (2-phenylpyridine), Ir (ppy) ₂ (acac) (bis (2-phenylpyridine) (acetylaceto) iridium (III)) or Ir (mpyp) ₃ Tris (2- (4-tolyl) phenylpyridine) iridium), C545T (10- (2-benzothiazolyl) -1,1,7,7-tetramethyl-2,3,6,7, -tetrahydro- 1H, 5H, 11H- [1] benzopyrano [6,7,8-ij] -quinolizin-11-one), but are not limited thereto.

(F ₂ ppy) ₂ Ir (tmd) as the blue dopant, F ₂ Irpic (bis [3,5-difluoro-2- (2- pyridyl) , Ir (dfppz) ₃ , DPVBi (4,4'-bis (2,2'-diphenylethen-1-yl) biphenyl), DPAVBi (4,4'- ) Biphenyl), or TBPe (2,5,8,11-tetra- tert -butylperylene), but the present invention is not limited thereto.

When the light emitting layer 125 includes a host and a dopant, the dopant may be selected from the range of about 0.01 to about 25 parts by weight based on 100 parts by weight of the host, but is not limited thereto.

The thickness of the light emitting layer 125 may be about 100 Å to about 500 Å. When the thickness of the light-emitting layer 125 satisfies the above range, it is possible to exhibit excellent light-emitting characteristics without increasing the actual driving voltage.

When a phosphorescent dopant is contained in the light emitting layer 125, a hole blocking layer (HBL) (not shown) may be formed between the light emitting layer 125 and the electron transporting layer to prevent triplet excitons or holes from diffusing into the electron transporting layer have.

A hole transporting layer 126 is formed on the light emitting layer 125. Examples of the material for forming the hole transport layer 126 include a phthalocyanine derivative, NPB (4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl), TPD (4,4'- (4,4 ', 4 "-tris [(3-methylphenyl) phenylamino] triphenylamine), TAPC (1,1-bis (9H-carbazol-9-yl) -N, N-bis [4- (9H-carbazol- (9,9 '- [1,1'-biphenyl] -4,4'-dibyl-9H-carbazole), mCP (9,9'- (3-phenylene) bis-9H-carbazole) or 2-TNATA (4,4 ', 4 "-tris (N- (2-naphthyl) 1 < / RTI >

The hole transport layer 126 may be formed by various methods such as a vacuum evaporation method, a spin coating method, a casting method, or an LB method. The thickness of the hole transport layer 126 may be from about 5 A to about 1,000 A. When the thickness of the hole transport layer 126 satisfies the above range, satisfactory hole transporting characteristics can be obtained without increasing the driving voltage substantially.

A hole injection layer 127 is formed on the hole transport layer 126. The hole injection layer 127 may be formed of a crystalline organic compound containing a cyano group, for example, hexaazatriphenylene hexacarbonitrile. The hole injection layer 127 may be formed by various methods such as a vacuum deposition method, a spin coating method, a casting method, or an LB method. The thickness of the hole injection layer 127 may be about 10 A to about 10,000 A. When the thickness of the hole injection layer 127 satisfies the above range, a satisfactory hole injection characteristic can be obtained without a substantial increase in drive voltage.

The upper electrode 130 is formed on the hole injection layer 127. The upper electrode 130 may be formed as a transparent electrode for both-side light emission. Preferably, a transparent material such as ITO (indium tin oxide), IZO (indium zinc oxide) or ZnO (zinc oxide), a thin film of graphene, Ag or Al can be used.

Next, a first light extraction enhancement layer 141 is formed on the upper electrode 130. The first light extracting enhancement layer 141 may be formed using a material having a refractive index similar to that of the transparent upper electrode 130 and a refractive index of about 1.4 to 2.2. As a material of the first light extracting enhancement layer 141, a common organic synthetic material can be used. For example, NPB can be used. The first light extraction enhancement layer 141 may be formed by a method such as ion beam deposition, electron beam deposition, plasma deposition, physical vapor deposition, chemical vapor deposition chemical vapor deposition, thermal deposition, atomic layer deposition, coating, or transfer.

Subsequently, a second light extracting enhancement layer 142 is formed under the substrate 101. The second light extraction enhancement layer 142 may be formed using a material having a refractive index similar to that of the substrate 101 and a refractive index of from about 1.4 to about 2.2.

The second light extraction enhancement layer 142 may be formed by attaching glass or plastic film-type under the substrate 101 using an index matching adhesive. For example, a PDMS (polydimethylsiloxane) micro lens array having a refractive index of about 1.5 may be used as the material of the second light extracting enhancement layer 142, and an ultraviolet ray hardening epoxy adhesive may be used as the refractive index matching adhesive, It is not.

Finally, a first anti-reflection layer 151 and a second anti-reflection layer 152 are formed on the first light extraction enhancement layer 141 and the second light extraction enhancement layer 142. A first light extraction enhancement layer 141 and the second light-extraction enhancement layer 142 are independently selected from _{LiF, MgF 2, CeF 3,} CaF 2, ScF 3, SiO 2, ITO, IZO, IGZO, TiO 2, SnO each other ₂ , ZnO, ZrO ₂ , Al ₂ O ₃ and Ta ₂ O ₅ , for example, by vacuum evaporation. At this time, the first light extraction enhancement layer 141 and the second light extraction enhancement layer 142 may be formed as a single layer or a plurality of layers. At this time, each of the single layer or the plurality of layers may be formed to a thickness of 30 nm to 150 nm. In the case of forming a plurality of layers, it is possible to form the high refractive index material and the low refractive index material alternately. For example, triple of MgF ₂ (n = 1.38) and _{Al 2 O 3 (n = 1.69} ) double-layer, or _{MgF 2 (n = 1.38),} ZrO 2 (n = 2.05) and _{Al 2 O 3 (n = 1.69} ) of The first light extraction enhancement layer 141 or the second light extraction enhancement layer 142 may be formed.

In this double-sided emission type organic light emitting device 200, the phenomenon that the spectrum of light emitted according to the viewing angle is changed is reduced and the injection characteristics of holes and electrons are good even though transparent electrodes are used at both ends, The reflected light that is guided is reduced, and the light emitting efficiency is excellent.

An n-type thin film transistor formed on the substrate and including a source electrode, a drain electrode, an oxide semiconductor layer, a gate electrode, and a gate insulating layer; An insulating layer formed on the n-type thin film transistor; And a double-sided emission type organic light emitting element described above formed on the insulating layer, wherein the lower electrode of the double-sided emission type organic light emitting element is electrically connected to one of the source electrode and the drain electrode.

The display device is useful for a flexible organic light emitting display device and an illumination device which are excellent in luminous efficiency and are currently in the display field.

Hereinafter, the organic light emitting device according to one embodiment will be described in more detail through non-limiting reference examples and examples, but the present invention is not limited to the following reference examples and examples.

Permeability measurement

Sample 1

A microlens array (MLA) (n = 1.52, NOA65 (Norland Product) film) having a thickness of 70 mu m was formed on a 0.7 mm thick glass substrate.

Sample 2

A 70 micron thick microlens array (MLA) (n = 1.52, NOA65 (Norland Product) film) was formed on a 0.7 mm thick glass substrate and a 990 ANGSTROM anti-reflective layer was coated on the MLA film.

3 is a graph showing light transmittance of Sample 1 and Sample 2. The transmittance was measured using a white light and an integrating sphere (6 inches, Labsphere). Referring to the graph of FIG. 3, the permeability of the MLA film coated with LiF of sample 2 over the range of 400-700 nm is higher than the transmittance of the MLA film of sample 1. It is believed that this is because the LiF film existing between the MLA film and the air reduces the reflection of light inside the MLA film and increases the light transmittance of the MLA film when light is transmitted from the MLA film to the air.

simulation

External Quantum Efficiency (EQE) was simulated for the structure of the double-side emission type organic light emitting device of Experimental Examples 1 to 15 below. The simulation was performed using a three dimensional geometric ray tracing simulation method (LightTools ^ⓒ ). In the simulation, the material was specified using optical properties.

Experimental Example  One

Ir (ppy) ₃ (92: 8 by weight) mixture of ITO glass substrate (700 Å) / B3PYMPM: Rb ₂ CO ₃ (85:15 weight ratio) (30 Å) / B3PYMPM (100 Å) / B3PYMPM and TCTA in a 1: 1 molar ratio (200 Å) / HAT-CN (500 Å) / lZO (600 Å) / TAPC

Experimental Example  2

Ir (ppy) ₂ (acac) (92: 8) mixture of ITO glass substrate (700 Å) / B3PYMPM: Rb ₂ CO ₃ (85:15 weight ratio) (30 Å) / B3PYMPM (100 Å) / B3PYMPM and TCTA (300 Å) / TAPC (200 Å) / HAT-CN (500 Å) / lZO (600 Å)

Experimental Example  3

Ir (ppy) ₂ (tmd) (92: 8) mixture of ITO glass substrate (700 Å) / B3PYMPM: Rb ₂ CO ₃ (85:15 weight ratio) (30 Å) / B3PYMPM (100 Å) / B3PYMPM and TCTA (300 Å) / TAPC (200 Å) / HAT-CN (500 Å) / lZO (600 Å)

Experimental Example  4

(70 탆) / ITO glass substrate (700 Å) / B3PYMPM: Rb ₂ CO ₃ (85:15 weight ratio) (30 Å) / B3PYMPM (70 탆) 100Å) / B3PYMPM and one of TCTA: 1 molar ratio _{mixture: Ir (ppy) 3 (92} : 8 weight ratio) (300Å) / TAPC (200Å ) / HAT-CN (500Å) / lZO (600Å) / microlens array layer ( α-NPD, 80 μm, n = 1.80)

Experimental Example  5

(70 탆) / ITO glass substrate (700 Å) / B3PYMPM: Rb ₂ CO ₃ (85:15 weight ratio) (30 Å) / B3PYMPM (70 탆) 100Å) / B3PYMPM and one of TCTA: 1 molar ratio _{mixture: Ir (ppy) 2 (acac} ) (92: 8 weight ratio) (300Å) / TAPC (200Å ) / HAT-CN (500Å) / lZO (600Å) / microlenses An array layer (? -NPD, 80 탆, n = 1.80)

Experimental Example  6

(70 탆) / ITO glass substrate (700 Å) / B3PYMPM: Rb ₂ CO ₃ (85:15 weight ratio) (30 Å) / B3PYMPM (70 탆) 100Å) / B3PYMPM and one of TCTA: 1 molar ratio _{mixture: Ir (ppy) 2 (tmd} ) (92: 8 weight ratio) (300Å) / TAPC (200Å ) / HAT-CN (500Å) / lZO (600Å) / microlenses An array layer (? -NPD, 80 탆, n = 1.80)

Experimental Example  7

LiF (990Å) / microlens array layer (semi-spherical shape and a diameter of 70㎛, height 35㎛, n = 1.52) (70㎛ ) / ITO glass substrate _{(700Å) / B3PYMPM: Rb 2} CO 3 (85:15 weight ratio) ( 30Å) / B3PYMPM (100Å) / B3PYMPM and one of TCTA: 1 molar ratio _{mixture: Ir (ppy) 3 (92} : 8 weight ratio) (300Å) / TAPC (200Å ) / HAT-CN (500Å) / lZO (600Å) / A microlens array layer (? -NPD, 80 탆, n = 1.80) / LiF (990 Å)

Experimental Example  8

LiF (990Å) / microlens array layer (semi-spherical shape and a diameter of 60㎛, height 30㎛, n = 1.52) (70㎛ ) / ITO glass substrate _{(700Å) / B3PYMPM: Rb 2} CO 3 (85:15 weight ratio) ( 30Å) / B3PYMPM (100Å) / B3PYMPM and one of TCTA: 1 molar ratio _{mixture: Ir (ppy) 2 (acac} ) (92: 8 weight ratio) (300Å) / TAPC (200Å ) / HAT-CN (500Å) / lZO ( (A-NPD, 80 탆, n = 1.80) / LiF (990 Å)

Experimental Example  9

LiF (990Å) / microlens array layer (semi-spherical shape and a diameter of 60㎛, height 30㎛, n = 1.52) (70㎛ ) / ITO glass substrate _{(700Å) / B3PYMPM: Rb 2} CO 3 (85:15 weight ratio) ( 30Å) / B3PYMPM (100Å) / B3PYMPM and one of TCTA: 1 molar ratio _{mixture: Ir (ppy) 2 (tmd} ) (92: 8 weight ratio) (300Å) / TAPC (200Å ) / HAT-CN (500Å) / lZO ( (A-NPD, 80 탆, n = 1.80) / LiF (990 Å)

Table 1 shows the results of simulating the external quantum efficiency of the double-side emission type organic light emitting device of Experimental Examples 1 to 9.

The light-
Dopant The first and second light extraction enhancing layers The first and second anti- EQE (%) EQE growth rate Experimental Example 1 Ir (ppy) ₃ X X 21.7 - Experimental Example 2 Ir (ppy) ₂ (acac) X X 25.7 - Experimental Example 3 Ir (ppy) ₂ (tmd) X X 27.5 - Experimental Example 4 Ir (ppy) ₃ O X 59.7 2.75 Experimental Example 5 Ir (ppy) ₂ (acac) O X 68.1 2.65 Experimental Example 6 Ir (ppy) ₂ (tmd) O X 71.5 2.60 Experimental Example 7 Ir (ppy) ₃ O O 65.5 3.02 Experimental Example 8 Ir (ppy) ₂ (acac) O O 73.8 2.87 Experimental Example 9 Ir (ppy) ₂ (tmd) O O 77.0 2.80

Referring to Table 1, the external photon efficiency was increased by 2.6-2.75 times as compared to Experimental Examples 1 to 3 in which the light extraction enhancement layer was not used in Experimental Examples 4 to 6 using the light extraction enhancement layer on the lower electrode and the upper electrode. Further, the external photon efficiency was increased by 2.8-3.0 times as compared with Experimental Examples 1 to 3 in Experimental Examples 7 to 9 using the antireflection layer on the light extracting enhancement layer.

Experimental Example  10

Except that the heights of the hemispheres of the microlens array were changed by 5 占 퐉 from 2.5 占 퐉 to 30 占 퐉 instead of 30 占 퐉.

Experimental Example  11

Except that the heights of the hemispheres of the microlens array were changed by 5 占 퐉 from 2.5 占 퐉 to 30 占 퐉 instead of 30 占 퐉.

Experimental Example  12

And the heights of the hemispheres of the microlens array were changed by 5 占 퐉 from 2.5 占 퐉 to 30 占 퐉 instead of 30 占 퐉.

Experimental Example  13

Except that the heights of the hemispheres of the microlens array were changed by 5 占 퐉 from 2.5 占 퐉 to 30 占 퐉 instead of 30 占 퐉.

Experimental Example  14

Except that the heights of the hemispheres of the microlens array were changed by 5 占 퐉 from 2.5 占 퐉 to 30 占 퐉 instead of 30 占 퐉.

Experimental Example  15

Except that the heights of the hemispheres of the microlens array were changed by 5 占 퐉 from 2.5 占 퐉 to 30 占 퐉 instead of 30 占 퐉.

Experimental Example  16

Except that the heights of the hemispheres of the microlens array were changed by 5 占 퐉 from 2.5 占 퐉 to 30 占 퐉 instead of 30 占 퐉.

Experimental Example  17

Except that the heights of the hemispheres of the microlens array were changed by 5 占 퐉 from 2.5 占 퐉 to 30 占 퐉 instead of 30 占 퐉.

Experimental Example  18

Except that the heights of the hemispheres of the microlens array were changed by 5 占 퐉 from 2.5 占 퐉 to 30 占 퐉 instead of 30 占 퐉.

4 is a graph showing the ratio of the external quantum efficiency of the organic light emitting devices of Experimental Example 13 and Experimental Example 16 to the external quantum efficiency of the organic light emitting devices of Experimental Example 10 according to height of the microlens array. 5 is a graph showing the ratio of the external quantum efficiency of the OLEDs of Experimental Example 14 and Experimental Example 17 to the external quantum efficiency of the OLEDs of Experimental Example 11 according to the height of the microlens array. 6 is a graph showing the ratio of the external quantum efficiency of the organic light emitting devices of Experimental Example 15 and Experimental Example 18 to the external quantum efficiency of the organic light emitting devices of Experimental Example 12 according to the height of the microlens array.

Referring to the graphs of FIGS. 3 to 5, the external quantum efficiency of all the heights of the microlens array is higher than that of Experimental Examples 16 to 18 in which the antireflection layer is applied, and Experiments 13 to 15 in which the antireflection layer is not applied.

100, 200: organic light emitting element 101: substrate
110: lower electrode 120: organic layer
123: n-doped layer 125: organic light emitting layer
126: Hole transport layer 127: Hole injection layer
130: upper electrode 141: first light extraction enhancement layer
142: second light extracting enhancement layer 224: second electron transporting layer

Claims (14)

Board;
A transparent lower electrode on the substrate;
A transparent upper electrode facing the lower electrode;
An organic layer interposed between the lower electrode and the upper electrode, the organic layer including a light emitting layer;
A first light extraction enhancement layer on the upper electrode;
A second light extraction enhancement layer on the substrate opposite to the lower electrode;
A first anti-reflection layer on the first light extracting enhancement layer; And
A second anti-reflection layer on the second light extracting enhancement layer; ≪ / RTI >
Wherein the first antireflection layer and the second antireflection layer are composed of a single layer or a plurality of layers of a material having a refractive index of 1.2 to 2.5;
Wherein the first light extracting enhancement layer comprises a plurality of first convex portions;
Wherein the second light extracting enhancement layer comprises a plurality of second convex portions. The method according to claim 1,
Wherein each of the single layer and each of the plurality of layers has a thickness of 30 nm to 200 nm independently of each other. The method according to claim 1,
When the first antireflection layer or the second antireflection layer comprises a plurality of layers, the plurality of layers include a low refractive index layer having a refractive index of 1.20 or more and less than 1.65 and a high refractive index layer having a refractive index of 1.65 or more and less than 2.50 And the low refractive index layer and the high refractive index layer are alternately arranged. The method according to claim 1,
The first anti-reflection layer and the second anti-reflection layer are, independently of each other _{LiF, MgF 2, CeF 3,} CaF 2, ScF 3, SiO 2, ITO, IZO, IGZO, TiO 2, SnO 2, ZnO, ZrO 2, Al ₂ O _3, and Ta ₂ O ₅ . The method according to claim 1,
Wherein the first convex portion has an inclination of 50 DEG to 80 DEG and a height of 50 to 100 mu m. The method according to claim 1,
Wherein the first convex portion has a conical shape, a polygonal pyramid shape, or a shape in which the upper surface thereof is cut off. The method according to claim 1,
Wherein the second convex portion has a conical shape, a pillar shape, a pyramid shape, or a lens shape. The method according to claim 1,
Wherein the organic layer includes a n-doped layer, a light emitting layer formed on the n-doped layer, a hole transporting layer formed on the light emitting layer, and a hole injection layer formed on the hole transporting layer and comprising a cyano group- device. 9. The method of claim 8,
Wherein the n-doped layer comprises a first electron transport material and at least one dopant selected from the group consisting of Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Cs ₂ CO ₃ , Rb ₂ CO ₃ , Ba ₂ CO ₃ , Pyronin B, DMC (decamethylcobaltocene), BEDTTTF (bis (ethylenedithio) -tetrathiafulvalene, bis (ethylenedithio) -tetrathiafulvalene), rhodamine B, TMBI (1,2,3-trimethyl-2-phenyl-2,3-dihydro-1H-benzoimidazole, 1,2,3-trimethyl- DMBI (1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzoimidazole, 1,3-dimethyl- dichlorophenyl-1,3-dimethyl-2,3-dihydro-1H-benzoimidazole, dichlorophenyl-1,3-dimethyl-2,3-dihydro-1H- benzoimidazole), N-DMBI (4- 3-dimethyl-2,3-dihydro-1H-benzoimidazole-2-yl) -phenyl) -dimethylamine, 4- -Yl) -phenyl) -dimethyl-amine), OH-DMBI (2- (1,3-dimethyl-2,3- dihydro-lH- benzoimidazol- phenol, 2- (1,3-dimethyl-2,3-dihydro-1H-benzoimidazol-2-yl) -phenol), PTCDI-C13 (N, N'-ditridecylperylene- -tetracarboxylic acid diimide, N, N'-ditridecylphenylene-3,4: 9,10-tetracarboxylic diimide) or F-PTCDI-C4 (N, N'-dibutyl-1,7-difluoroperylene -3,4: 9,10-tetracarboxylic acid diimide, N, N'-dibutyl-1,7-difluoroperylene-3,4: 9,10-tetracarboxylic acid diimide) Emitting organic light-emitting device. 9. The method of claim 8,
The n- doping layer is _{Li 2 CO 3, Na 2 CO} 3, K 2 CO 3, Cs 2 CO 3, Rb 2 CO 3, Ba 2 CO 3, non-B blood, DMC, BEDTTTF, rhodamine B, TMBI, A first electron transporting layer comprising an impurity layer made of at least one of DMBI, Cl-DMBI, N-DMBI, OH-DMBI, PTCDI-C13 or F- Emitting organic light-emitting device. 9. The method of claim 8,
Wherein the cyano group-containing compound is hexaazatriphenylene hexacarbonitrile (HAT-CN). The method according to claim 1,
Wherein the first light extraction enhancement layer and the second light extraction enhancement layer have refractive indices of 1.4 to 2.2 independently of each other. A display device comprising the double-sided emission type organic light-emitting device according to any one of claims 1 to 12. 13. A lighting comprising the double-sided light emitting type organic light-emitting device according to any one of claims 1 to 12.

Images