KR101468064B1 - Method of organic light-emitting diode comprising a film-type light extraction enhancing layer - Google Patents

Abstract

Providing a substrate; Forming a lower electrode on the substrate; An n-doped layer on the lower electrode; An organic light emitting layer; Forming an organic layer including a hole injection layer made of a crystalline organic compound containing a hole transporting layer and a cyano group; Forming a transparent upper electrode on the organic layer; And attaching a first light extraction enhancement layer made of a first film having a first light extraction pattern on the upper electrode.

Description

[0001] The present invention relates to a method of manufacturing an organic light emitting device including a film-type light extracting enhancement layer,

And more particularly, to an organic light emitting device including a light extraction enhancement layer 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.

A general organic light emitting device includes a substrate, an anode, a hole injecting layer, a hole transporting layer, a light emitting layer, an electron transporting layer, an electron injecting layer, and a cathode in this order, and the inverted organic light emitting device includes a substrate, , A light emitting layer, a hole transporting layer, a hole injecting layer, and an anode in this order. The double-sided emission type organic light emitting device is made of a material in which both the anode and the cathode are transparent in these structures.

The driving principle of the organic light emitting device is as follows. When a voltage is applied between the anode and the cathode of the organic light emitting diode, holes injected from the anode move to the light emitting layer via the hole transporting layer, electrons injected from the cathode travel to the light emitting layer via the electron transporting layer, Is recombined in the light emitting layer to generate an exciton, and the exciton is changed from the excited state to the ground state and light is emitted.

The conventional 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, 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, a method of introducing a photonic crystal structure having a specific size and arrangement interval between the transparent electrode and the glass substrate, or making the device itself a corrugated structure or a wrinkled structure has been proposed.

In order to improve the light extraction at the interface between the transparent electrode and the glass substrate, a photonic crystal structure having a specific size and arrangement interval can be introduced between the transparent electrode and the glass substrate by applying the same principle in the case of the double-side emission type organic light emitting device In this case, a viewing angle dependency problem in which the spectrum of light emitted varies depending on the viewing angle, a problem of hole and electron injection due to the transparent electrode, and the like are caused, and it is difficult to obtain a satisfactory result.

And a method of manufacturing an organic light emitting device capable of improving light extraction efficiency by a simple process.

Providing a substrate along one side; Forming a lower electrode on the substrate; Forming an organic layer including a hole injection layer made of a crystalline organic compound containing an n-doped layer, a light emitting layer, a hole transporting layer, and a cyano group on the lower electrode; Forming a transparent upper electrode on the organic layer; And attaching a first light extraction enhancement layer comprising a first film having a light extraction pattern on the upper electrode; And a method of manufacturing the organic light emitting device.

The first film may be formed of a material such as an acrylic resin, a polyester resin, an epoxy resin, a polystyrene resin, a polycarbonate resin, a polyurethane resin, a styrene-acrylonitrile copolymer or a styrene-methyl methacrylate copolymer Lt; / RTI >

The first light extracting enhancement layer may have a visible light transmittance of 70% to 99% and a refractive index of 1.5 to 2.2.

Wherein the first light extraction enhancement layer has a first incident surface contacting the upper electrode and a first exit surface located on the opposite side of the first incident surface, the light extracting pattern comprising a plurality of And the first scattering structure.

The first scattering structure may have a conical shape, a pillar shape, a cone shape, a pyramid shape, or a lens shape. In this case, a fill factor defined as a value obtained by dividing the surface area of the plurality of first scattering structures by the area of the first exit surface may be 50% to 100%. Meanwhile, the first scattering structure may have a lens shape having a bottom diameter of 1 탆 to 500 탆.

The first film can be formed by a method such as nanoimprinting, sputtering, deposition polymerization, electron beam evaporation, plasma deposition, chemical vapor deposition, sol-gel method, ink-jet printing, spin coating or offset printing have.

The step of attaching the first light extracting enhancement layer may use an index matching adhesive.

The hole injection layer may be formed of HAT-CN (hexaazatriphenylene hexacarbonitrile).

The upper electrode may include ITO (indium tin oxide), IZO (indium zinc oxide), ZnO (zinc oxide), or SnO ₂ (tin oxide).

The lower electrode may be formed of a transparent material.

And attaching a second light extraction enhancement layer made of a second film having a light extraction pattern on the substrate opposite to the organic layer.

The second film may be formed of a material such as an acrylic resin, a polyester resin, an epoxy resin, a polystyrene resin, a polycarbonate resin, a polyurethane resin, a styrene-acrylonitrile copolymer, or a styrene-methyl methacrylate copolymer Lt; / RTI >

The second light extracting enhancement layer has a second incident surface contacting the upper electrode and a second exit surface positioned on the opposite side of the second incident surface, and the second light extracting pattern is formed on the second exit surface And may include a plurality of second scattering structures.

Wherein the first scattering structure has a cone shape, a pillar shape, a cone shape, a pyramid shape, or a lens shape, and a fill factor defined by a value obtained by dividing the surface area of the plurality of first scattering structures by the area of the first exit surface is 50 % ≪ / RTI > to 100%.

The first scattering structure may have a lens shape whose bottom surface has a diameter of 1 탆 to 500 탆.

According to one aspect of the present invention, there is provided a method of manufacturing an organic light emitting device having a light extracting enhancement layer, wherein a film having a light extracting pattern is adhered on an upper electrode, thereby simplifying the light extraction efficiency without complicated processes such as vacuum deposition can do.

FIG. 1 is a cross-sectional view schematically illustrating the structure of a top 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 one embodiment.
3 is a cross-sectional view schematically showing the structure of a double-side emission type organic light emitting device according to another embodiment.
4 is a cross-sectional view schematically showing the structure of a double-side emission type organic light emitting device according to another embodiment.

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.

FIG. 1 is a cross-sectional view schematically illustrating the structure of a top emission type organic light emitting diode 100 according to an embodiment. Referring to FIG.

1, an organic light emitting diode 100 includes a substrate 101, a lower electrode 110 formed on the substrate 101, an organic layer 120 formed on the lower electrode 110, A transparent upper electrode 130 formed on the organic layer 120 and a first light extraction enhancement layer 141 formed on the upper electrode 130. The first light extraction enhancement layer 141 is formed on the organic layer 120,

The organic layer 120 is formed on the electron transport layer 122, the emission layer 125 formed on the electron transport layer 122, the hole transport layer 126 formed on the emission layer 125, and the hole transport layer 126 And a hole injection layer 127 made of a crystalline organic compound containing a cyano group. Alternatively, an electron injection layer (not shown) may be further formed between the lower electrode 110 and the electron transport layer 122. Alternatively, a metal reflection film (not shown) made of a metal having good reflectivity such as silver (Ag) or aluminum (Al) may be selectively formed on the substrate 101 and a buffer layer (not shown) for preventing diffusion of metal impurities from the substrate to the organic layer (Not shown) may be present.

In the organic light emitting diode 100 as described above, the phenomenon that the spectrum of light emitted according to the viewing angle changes due to the use of the light extraction enhancement layer is reduced, and a wide viewing angle can be secured. Further, by forming the hole injection layer with a crystalline organic compound containing a cyano group, the strength of the hole injection layer is improved, and the upper electrode on the hole injection layer can be formed as a transparent conductive metal oxide. Accordingly, the organic light emitting diode 100 emits light to the front surface through the transparent upper electrode.

A method of manufacturing the top emission type organic light emitting diode 100 according to one embodiment will be described with reference to FIG.

As the substrate 101, a substrate used in a conventional organic light emitting device can be used. A glass substrate or a transparent plastic substrate having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and water resistance can be used. For example, as the substrate 101, a transparent glass substrate having SiO ₂ as a main component can be used. On the other hand, when the substrate 101 is a bottom emission type in which light is emitted in the direction of the substrate 101, the substrate 101 must be formed of a transparent material. However, in the case of a front emission type in which light is implemented in a direction opposite to the substrate 101, Is not necessarily formed of a transparent material. In this case, the substrate 101 may be formed of a metal such as iron, chromium, manganese, nickel, titanium, molybdenum, or stainless steel, but is not limited thereto.

The lower electrode 110 is formed on the substrate. The lower electrode 110 may be electrically connected to the driving transistor to receive a driving current from the driving transistor. The lower electrode 110 may be, for example, a cathode.

The lower electrode 110 may be formed of a transparent metal oxide such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), ZnO (Zinc Oxide), or SnO ₂ (tin oxide), graphene, , LiF-Al, Mg: Ag, or Ca-Ag. (Mg), silver (Ag), aluminum (Al), aluminum: lithium (Al: Li), calcium (Ca), silver: indium tin oxide (Ag: ITO) The lower electrode 110 may be formed as a reflective electrode by using magnesium: silver (Ag: Ag) or the like. The lower electrode 110 can be formed by various known methods, for example, sputtering or vacuum deposition.

The electron transport layer 122 may be formed on the lower electrode 110. [ The electron transporting layer 122 can be formed using a known electron transporting material. The electron transport layer 122 may be formed of, for example, B3PYMPM (bis-4,6- (3,5-di-3-pyridylphenyl) -2- methylpyrimidine), Bphen - phenanthroline), BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), TPBi (2,2 ', 2 "-( 1,3,5- ) -Tris (1-phenyl-1H-benzimidazole), TPQ1 (tris-phenylquinoxalines 1,3,5-tris [ Benzene), TPQ2 (tris-phenylquinoxalines 1,3,5-tris [{3- (4-tert- butylphenyl) -6-trifluoromethyl} quinoxalin- Tert-butylphenyl-1,2,4-triazole), NTAZ (4- (naphthalen-1-yl) -3,5-diphenyl- 4H-1,2,4-triazole), tBu-PBD (2- (4-biphenyl) -5- (4-tert- butylphenyl) -1,3,4- oxadiazole), BeBq ₂ (10-benzo [h] quinolinol-beryllium), E3 (perfluorene), or two or more of them.

The electron transporting layer 122 can 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 electron transporting layer 122 may be from about 10 A to about 1,000 A, for example, from about 150 A to about 500 A. When the thickness of the electron transporting layer 122 satisfies the above range, satisfactory electron transporting characteristics can be obtained without increasing the driving voltage substantially.

The light emitting layer 125 is formed on the electron transporting layer 122. 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 a substantial increase in driving voltage.

When a phosphorescent dopant is included in the light emitting layer 125, a hole blocking layer (HBL) (not shown) is formed between the light emitting layer 125 and the electron transporting layer 122 to prevent the triplet excitons or holes from diffusing into the electron transporting layer 122 ) May be formed. For example, BCP can be used as a material for the hole blocking layer.

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 NPB (4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl), TPD (4,4'- (3-methylphenyl) -N- phenylamino] biphenyl), MTDATA (4,4 ', 4 "-tris [(3- methylphenyl) phenylamino] triphenylamine, TAPC (9H-carbazol-9-yl) -N, N-di-p-tolylamino) phenyl) cyclohexane), TCTA ) Phenyl] -benzenamine), CBP (9,9 '- [1,1'-biphenyl] -4,4'-diylbis-9H-carbazole), Alq3, mCP (9,9' (1, 3-phenylene) bis-9H-carbazole) and 2-TNATA (4,4 ', 4 "-tris Species.

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 10 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 is preferably formed of a layer made of a single material which is not doped. When a layer made of a single material is used, damage to the organic layer can be prevented while having a satisfactory level of hole injection characteristics without a substantial increase in driving voltage. The hole injection layer 127 may be formed of a crystalline organic compound containing a cyano group, for example, HAT-CN (hexaazatriphenylene hexacarbonitrile).

The crystalline organic compound containing a cyano group such as HAT-CN in the hole injection layer 127 exhibits lattice or crystallization properties, and thus the hole injection layer 127 can have mechanical strength. Therefore, when the upper electrode 130 is formed by sputtering, the hole injection layer 127 can protect the underlying organic layer from the impact damage that may occur during the formation of the upper electrode 130.

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 is within the above range, a satisfactory hole injection characteristic can be obtained without a substantial increase in drive voltage, and the organic layer under the lower electrode 130 can be protected when the upper electrode 130 is formed.

The upper electrode 130 is formed on the hole injection layer 127. The upper electrode 130 may be formed as a transparent electrode for light emission over the entire surface. For example, the upper electrode 130 may be formed of a transparent metal oxide such as ITO (indium tin oxide), IZO (indium zinc oxide), ZnO (zinc oxide) or SnO ₂ (tin oxide), graphene, Of a transparent metal such as Ag, Al, LiF-Al, Mg: Ag or Ca-Ag.

Subsequently, a first light extraction enhancement layer 141 is formed on the upper electrode 130. The first light extraction enhancement layer 141 may be formed by attaching a film on which the nano- or micro-sized light extraction pattern is formed on the upper electrode 130. At this time, the first light extraction enhancement layer 141 may be attached on the upper electrode 130 using an index matching adhesive.

The first light extraction enhancement layer 141 may be formed of an organic material, an inorganic material, or a mixture thereof having a refractive index similar to that of the transparent upper electrode 130, a refractive index of about 1.4 to 2.2. The first light extracting enhancement layer 141 may be formed of, for example, glass or an acrylic resin, a polyester resin, an epoxy resin, a polystyrene resin, a polycarbonate resin, a polyurethane resin, a styrene-acrylonitrile copolymer, -Methyl methacrylate copolymer and the like. For example, a PDMS polymer having a refractive index of about 1.4 may be used as the material of the first light extracting enhancement layer 141, and a thermosetting or ultraviolet ray hardening epoxy adhesive may be used as the refractive index matching adhesive. The first light extracting enhancement layer 141 has a transparent property for the whole light emission. The first light extraction enhancement layer 141 may have a visible light transmittance of about 70% to about 99%.

If a 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 a surface located on the opposite side of the first incident surface is defined as a first emission surface, A plurality of first scattering structures may be arranged on the surface. The arrangement of the first scattering structure, which is a pattern for extracting light, may cause 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 scattering structure is formed to be a wavelength range of visible light, the first scattering structure can act as a scattering body for the visible light emitted through the upper electrode 130, thereby improving the extraction of visible light . Since the light scattering shape is determined according to the shape and the period of the first scattering structure, the shape and period of the first scattering structure are formed to be suitable for scattering of the monochromatic light wavelength, so that the extraction characteristic of light emitted to the outside of the upper electrode 130 can be controlled have.

The first scattering structure may have, for example, a conical shape, a pillar shape, a polygonal pyramidal shape such as a triangular pyramid or a quadrangular pyramid, or a lens shape. When the first scattering structure has the above-described shape, 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 first scattering structure can be changed according to the shape of the first scattering structure and the wavelength of scattered light.

The fill factor of the first scattering structure is defined as a value obtained by dividing the surface area of the plurality of first scattering structures formed on the first incident surface by the area of the first emitting surface, 50% to about 100%, scattering by the first scattering structure is suitable, so that the light extraction characteristics can be satisfactory.

For example, the first scattering structure may be cone-shaped, in which case the height of the first scattering structure may be 1 [mu] m to 500 [mu] m, the diameter of the underside may be 1 [mu] m to 500 [ %. ≪ / RTI > The thickness of the first light extracting enhancement layer 141 may be determined according to the height of the first scattering structure. That is, the height of the first scattering structure corresponds to the thickness of the first light extracting enhancement layer 141.

The film for the first light extracting enhancement layer 141 in which the light extracting pattern is formed may be formed by a known technique such as nanoimprinting, sputtering, vapor deposition polymerization, electron beam evaporation, plasma evaporation, chemical vapor deposition, sol- Method, an offset printing method, or the like.

As described above, the method of manufacturing an organic light emitting device according to the present invention includes forming the light extraction enhancement layer on the upper electrode by a film deposition method, thereby simplifying the process and reducing the cost compared with the case of forming the light extraction enhancement layer on the upper electrode by vapor deposition can do.

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

2, the organic light emitting device 200 includes a substrate 201, a transparent lower electrode 210 formed on the substrate 201, an organic layer 220 formed on the lower electrode 210, A first light extraction enhancement layer 141 formed on the upper electrode 130 and a transparent upper electrode 130 formed on the organic layer 220 facing the first electrode 210 and formed on the outer surface of the substrate 201. [ And a second light extraction enhancement layer (142).

The organic layer 220 includes an n-doped layer 223, a light emitting layer 125 formed on the n-doped layer 223, a hole transport layer 126 formed on the light emitting layer 125, And a hole injection layer 127 made of a crystalline organic compound containing a cyano group.

The organic light emitting device 200 will be described focusing on differences from the organic light emitting device 100 of FIG.

The substrate 201 is made of a transparent material such as glass or transparent plastic for light emission on both sides and the lower electrode 210 is also made of a transparent material such as a transparent conductive oxide for backlight emission.

The n-doped layer 223 is a layer that generates electrons when a voltage is applied to the device, and the electrons can be injected and transported into the light emitting layer 125. When the negative voltage is applied to the lower electrode 230 and the positive electrode is applied to the upper electrode 130, the energy barrier at the interface between the n-doped layer 223 and the lower electrode 230 is lowered, The injection and transport of electrons can be facilitated irrespective of the work function value of the electron transport layer 230. Accordingly, the selection width of the lower electrode 230 of the device can be widened, and the transparent conductive oxide can be selected as the lower electrode 230.

The n-doped layer 223 may be in the form of a bilayer in which a first electron transporting layer 223 " is laminated on the impurity layer 223 'as shown in Figure 2. In this case, the impurity layer 223' The energy barrier at the interface between the lower electrodes 230 is lowered so that the injection and transport of electrons can be facilitated irrespective of the work function of the lower electrode 230. Alternatively, the n-doped layer 223 can be electron transported Lt; RTI ID = 0.0 > n-dopant < / RTI >

The second light extracting enhancement layer 242 is a layer for increasing light extraction efficiency of light emitted toward the substrate 201.

Since the organic light emitting device 200 as described above can emit light on both sides and the use of the light extraction enhancement layer on the front and back surfaces of the device reduces the phenomenon of the spectrum of light emitted according to the viewing angle, .

Referring to FIG. 2, the manufacturing method of the double-side emission type organic light emitting device 200 according to one embodiment will be described focusing on differences from the manufacturing method of the organic light emitting device 100 of FIG.

Since the organic light emitting device 200 includes not only front light but also back light, the substrate 201 is formed of a transparent material. The substrate 201 may be a substrate used in a conventional organic light emitting device. A glass substrate or a transparent plastic substrate having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and water resistance can be used. For example, as the substrate 101, a transparent glass substrate having SiO ₂ as a main component can be used.

The lower electrode 210 may be formed of a transparent metal oxide such as ITO, IZO, ZnO or SnO ₂ , graphene, or a thin layer of Ag, Al, LiF-Al, Mg: Ag or Ca- It can be formed using a transparent metal such as Ag. The lower electrode 210 may be formed using various known methods, for example, a sputtering method or a vacuum deposition method.

An n-doped layer 223 is formed on the lower electrode 210. The n-doped layer 223 may be formed as a double layer in which a first electron transporting layer 223 "including an electron transporting material is laminated on an impurity layer 273 'containing an n-dopant as an impurity.

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, Dys and Yb; A nitride of the metal; A carbonate of the metal; And complexes of said metals; 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 and Ba ₂ CO ₃ can be used as an n-dopant.

As the first electron transporting material, a known electron transporting material may be used. The first electron transporting material may be, for example, B3PYMPM (bis-4,6- (3,5-di-3-pyridylphenyl) -2- methylpyrimidine), Bphen - phenanthroline), BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), TPBi (2,2 ', 2 "-( 1,3,5- ) -Tris (1-phenyl-1H-benzimidazole), TPQ1 (tris-phenylquinoxalines 1,3,5-tris [ Benzene), TPQ2 (tris-phenylquinoxalines 1,3,5-tris [{3- (4-tert- butylphenyl) -6-trifluoromethyl} quinoxalin- Tert-butylphenyl-1,2,4-triazole), NTAZ (4- (naphthalen-1-yl) -3,5-diphenyl- 4H-1,2,4-triazole), tBu-PBD (2- (4-biphenyl) -5- (4-tert- butylphenyl) -1,3,4- oxadiazole), BeBq ₂ (10-benzo [h] quinolinol-beryllium), E3 (perfluorene), or two or more of them.

The impurity layer 223 'can be formed by a method such as vacuum deposition, sputtering, vapor deposition polymerization, electron beam deposition, plasma deposition, chemical vapor deposition, sol-gel method, inkjet printing, spin coating, The first electron transporting layer 223 "may be formed by a method such as a vacuum evaporation method, a spin coating method, a casting method, an LB method, etc. The thickness of the impurity layer 223 'is about 5 Å to about 100 Å, From about 10 A to about 50 A, and the thickness of the first electron transporting layer 223 "may be from about 10 A to about 1,000 A or from about 100 A to about 500 A. When the thicknesses of the impurity layer 223 'and the first electron transporting layer 223' are within the above ranges, the impurity layer 223 'and the first electron transporting layer 223' Electrons can be generated.

Alternatively, the n-doped layer 223 may be formed by doping an electron transport material with an n-dopant. The electron transporting material may be an electron transporting material used for the first electron transporting layer 223 ", and the n-dopant may be an n-dopant used for the impurity layer 273 '.

The doping concentration of the n-dopant may be about 0.1% to 25% by weight based on the total weight of the n-doped layer 223. The n-doped layer 223 can 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 223 may be from about 10 A to about 1000 A. [ When the thickness of the n-doped layer 223 satisfies the above range, electrons can be generated to a satisfactory level in the n-doped layer 223 without a substantial increase in driving voltage.

The light emitting layer 125, the hole transport layer 126, the hole injection layer 127, the upper electrode 130 and the first light extracting enhancement layer 141 are formed by the same method as the method of manufacturing the organic light emitting device 100 of FIG. .

In addition, a second light extraction enhancement layer 142 is formed on the outer surface of the substrate 201. The second light extracting enhancement layer 242 may be formed by attaching a film on which the nano- or micro-sized light extracting pattern is formed on the substrate 201, like the first light extraction enhancement layer 141. At this time, the second light extracting enhancement layer 242 can be attached onto the substrate 201 using the refractive index matching adhesive.

The second light extraction enhancement layer 242 may be formed of an organic material, an inorganic material, or a mixture thereof having a refractive index similar to that of the substrate 201, a refractive index of about 1.4 to 2.2. The second light extracting enhancement layer 242 may be formed of, for example, glass or an acrylic resin, a polyester resin, an epoxy resin, a polystyrene resin, a polycarbonate resin, a polyurethane resin, a styrene- acrylonitrile copolymer, -Methyl methacrylate copolymer and the like. For example, a PDMS polymer having a refractive index of about 1.4 may be used as the material of the second light extracting enhancement layer 242, and an ultraviolet ray hardening epoxy adhesive may be used as the refractive index matching adhesive. The second light extraction enhancement layer 242 has a transparent characteristic for back light emission. The visible light transmittance of the second light extract enhancement layer 242 may be from about 70% to about 99%.

In the second light extraction enhancement layer 242, a surface that contacts the substrate 201 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 scattering structures may be arranged. The arrangement of the second scattering structure, which is a pattern for extracting light, may cause light scattering and improve extraction efficiency of light emitted from the light emitting layer 125 through the substrate 201 to the outside. Specifically, if the repetition period of the second scattering structure is formed to be the wavelength range of the visible light, the second scattering structure can act as a scatterer for visible light emitted through the substrate 201, thereby improving the extraction of visible light. Meanwhile, since the light scattering pattern is determined according to the shape and the period of the second scattering structure, the shape and period of the second scattering structure can be adjusted to the scattering of the monochromatic light wavelength, and the light extracting characteristic of the light emitted to the outside of the substrate 201 can be controlled .

The second scattering structure may have a conical shape, a pillar shape, a cone shape, a pyramid shape, or a lens shape. When the second scattering structure 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 scattering structure can be changed according to the shape of the second scattering structure and the wavelength of scattered light.

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

For example, the second scattering structure may be in the form of a lens, in which case the height of the second scattering structure may be 1 [mu] m to 500 [mu] m, the diameter of the underside may be 1 [ %. ≪ / RTI > On the other hand, the thickness of the second light extracting enhancement layer 242 may be in the range of 1 탆 to 500 탆 including the height of the second scattering structure.

The film for the second light extracting enhancement layer 242 having the light extracting pattern formed thereon may be subjected to various processes such as nanoimprinting, sputtering, vapor deposition polymerization, electron beam deposition, plasma deposition, chemical vapor deposition An evaporation method, a sol-gel method, an inkjet printing method, a spin coating method, an offset printing method, or the like.

3 is a cross-sectional view schematically showing the structure of a double-side emission type organic light emitting diode 300 according to another embodiment.

3, the organic light emitting device 300 includes a substrate 201, a transparent lower electrode 210 formed on the substrate 201, an organic layer 220 formed on the lower electrode 210, A first light extraction enhancement layer 141 formed on the upper electrode 130 and a transparent upper electrode 130 formed on the organic layer 220 facing the first electrode 210 and formed on the outer surface of the substrate 201. [ And a second light extraction enhancement layer (142).

The organic layer 220 includes an n-doped layer 223, a second electron transport layer 324 formed on the n-doped layer 223, a light emitting layer 125 formed on the second electron transport layer 324, A hole transport layer 126 formed on the hole injection layer 125 and a hole injection layer 127 formed on the hole transport layer 126 and made of a crystalline organic compound containing a cyano group.

The organic light emitting device 300 of FIG. 3 differs from the organic light emitting device 200 of FIG. 2 in that a second electron transporting layer 324 is formed on the n-doped layer 223. The second electron transporting layer 324 can smoothly transport electrons from the n-doped layer 223 to the light-emitting layer 125.

A second electron transport layer 324 and formed using the electron transport material, for example B3PYMPM, Bphen, BCP, TPBi, TPQ1, TPQ2, TAZ, NTAZ, tBu-PBD, BeBq _2, E3, or two or more kinds of these But is not limited thereto.

The second electron transporting layer 324 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 second electron transporting layer 324 may be between about 10 Å and about 1000 Å. When the thickness of the second electron transporting layer 324 satisfies the above range, satisfactory electron injection and transportation characteristics can be obtained without increasing the driving voltage substantially. The manufacturing method of the organic light emitting device 300 of FIG. 3 is the same as the method of forming the organic light emitting device 200 of FIG. 2 except for forming the second electron transporting layer 324.

4 is a cross-sectional view schematically showing the structure of a double-side emission type organic light emitting device 400 according to another embodiment.

4, an encapsulation layer 432 is formed on the upper electrode 130 and a first light extraction enhancement layer 141 is formed on the encapsulation layer 432 The organic light emitting device 300 of FIG. 3 differs from the organic light emitting device 300 of FIG.

The sealing layer 432 can prevent moisture, oxygen, and the like from penetrating into the organic light emitting element to deteriorate the device. The sealing layer 432 may be formed of an organic film, an inorganic film, or a mixed organic / inorganic composite film. For example, the encapsulation layer 432 may be formed of an alternate layer of an organic film of an acrylate or epoxy type and an inorganic film of an oxide, nitride, or oxynitride of silicon, aluminum, tin, or titanium. The sealing layer 432 can be formed to a thickness of, for example, 1 占 퐉 to 10 占 퐉, but is not limited thereto. The inorganic film can be formed by a method such as chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), sputtering, atomic layer deposition (ALD), or thermal evaporation. The organic film may be formed using, for example, a flash evaporator method, an inkjet process, or a screen printing method and a heat treatment.

The first light extracting enhancement layer 141 may be formed by attaching a film having a nano- or micro-sized light extracting pattern on the sealing layer 432. [ The manufacturing method of the organic light emitting device 400 of FIG. 4 is the same as the method of forming the organic light emitting device 300 of FIG. 3 except for forming the sealing layer 432.

The first light extraction enhancement layer 141 on the encapsulation layer 432 can also be formed using a film deposition method and the light extraction and enhancement layer 141 can be formed using a method similar to the case where the first light extraction enhancement layer 141 is formed on the upper electrode 130 An organic light emitting device having improved efficiency can be manufactured.

100, 200, 300: organic light emitting element 101, 201: substrate
110, 210: lower electrode 120, 220, 230: organic layer
126: Hole transport layer 127: Hole injection layer
130: upper electrode 141: first light extraction enhancement layer
242: second light extracting enhancement layer 223: n-doped layer
223 ': impurity layer 223': first electron transporting layer
324: Second electron transport layer

Claims (17)

Providing a substrate;
Forming a lower electrode on the substrate;
An n-doped layer on the lower electrode; An organic light emitting layer; Forming an organic layer including a hole injection layer made of a crystalline organic compound containing a hole transporting layer and a cyano group;
Forming a transparent upper electrode on the organic layer; And
And attaching a first light extraction enhancement layer made of a first film having a light extraction pattern on the upper electrode,
Wherein the first light extraction enhancement layer has a first incident surface in contact with the upper electrode and a first exit surface located on the opposite side of the first incident surface, A method of manufacturing an organic light emitting device comprising a first scattering structure. The method according to claim 1, wherein the first film is formed of an acrylic resin, a polyester resin, an epoxy resin, a polystyrene resin, a polycarbonate resin, a polyurethane resin, a styrene-acrylonitrile copolymer, Wherein the organic material comprises a substance of a copolymer. The method of claim 1, wherein the first light extracting enhancement layer has a visible light transmittance of 70% to 99% and a refractive index of 1.4 to 2.2. delete [2] The apparatus according to claim 1, wherein the first scattering structure has a cone shape, a pillar shape, a polygonal pyramid shape, or a lens shape, and is defined as a value obtained by dividing the surface area of the plurality of first scattering structures by the area of the first exit surface Wherein the fill factor is 50% to 100%. The method of claim 1, wherein the first scattering structure has a lens shape having a bottom diameter of 1 to 500 mu m. The method of claim 1, wherein the first film is formed by a method selected from the group consisting of a nanoimprinting method, a sputtering method, a deposition polymerization method, an electron beam evaporation method, a plasma deposition method, a chemical vapor deposition method, Gt; < / RTI & 2. The method of claim 1, wherein the step of attaching the first light extraction enhancing layer uses an index matching adhesive. The method of claim 1, wherein the hole injection layer is formed of hexaazatriphenylene hexacarbonitrile (HAT-CN). The method of claim 1, wherein the upper electrode comprises ITO (indium tin oxide), IZO (indium zinc oxide), ZnO (zinc oxide), or SnO ₂ (tin oxide). The method of claim 1, wherein the lower electrode is formed of a transparent material. 12. The method of claim 11, further comprising the step of attaching a second light extraction enhancement layer comprising a second film having a light extraction pattern on the substrate opposite the organic layer. [12] The method of claim 12, wherein the second film is formed of an acrylic resin, a polyester resin, an epoxy resin, a polystyrene resin, a polycarbonate resin, a polyurethane resin, a styrene- acrylonitrile copolymer, Wherein the organic material comprises a substance of a copolymer. 14. The light-emitting device according to claim 13, wherein the second light extracting enhancement layer has a second light incidence surface in contact with the upper electrode and a second light incidence surface on the opposite side of the second light incidence surface, And a plurality of second scattering structures formed on the second emitting surface. 15. The method of claim 14, wherein the second scattering structure has a conical shape, a pillar shape, a cone shape, a pyramid shape, or a lens shape, and the surface area of the plurality of second scattering structures is divided by the area of the second exit surface Wherein the defined fill factor is 50% to 100%. 15. The method of manufacturing an organic light emitting diode according to claim 14, wherein the second scattering structure has a lens shape having a bottom diameter of 1 to 500 mu m. The method of claim 1, further comprising forming an encapsulation layer on the upper electrode, wherein the first light extraction enhancement layer is formed on the encapsulation layer.

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