KR20080009522A - White organic light-emitting device - Google Patents

Abstract

A white organic light emitting device is provided to improve color reproduction by emitting white light similar to natural light. A white organic light emitting device includes an anode layer(11), a hole injection layer(12), a hole transfer layer(13), a light emitting layer(14), and a cathode layer(17). The light emitting layer has a first light emitting layer(14a), a second light emitting layer(14b), and a hybrid layer(14c) which is formed by mixing and depositing the host material of the first light emitting layer and the host material of the second light emitting layer. The mixing weight ratio of the host material of the first light emitting layer and the second light emitting layer of the hybrid layer is 33:67 or 67:33.

Description

White Organic Light-Emitting Device

1 is a cross-sectional view showing the structure of a conventional three wavelength white organic light emitting display device;

2 is a cross-sectional view showing the structure of another conventional three-wavelength white organic light emitting display device;

3 is a cross-sectional view showing the structure of a white organic light emitting display device according to an embodiment of the present invention;

4a and 4b is a schematic view of the color filter and assembly for measuring the device according to the invention,

5 and 6 are EL light emission spectra of the white organic light emitting display device according to the embodiments of the present invention;

7 is a diagram illustrating color reproducibility using a white organic light emitting display device and a color filter according to an exemplary embodiment of the present invention.

** Description of the major symbols in the drawings **

1: white organic electroluminescent device

10: substrate 11: anode layer

12: hole injection layer 13: hole transport layer

14 light emitting layer 14a first light emitting layer

14b: second light emitting layer 14c: mixed layer

15: electron transport layer 16: electron injection layer

17: cathode layer 20: color filter

The present invention relates to a white organic electroluminescent device.

The most widely used liquid crystal display (LCD) is a non-light-emitting display device, which consumes little power and is light in weight, but the device driving system is complicated and the response time, contrast and other characteristics are not satisfactory. Therefore, research on organic electroluminescence devices (organic electroluminescence devices), which are recently attracting attention as next-generation flat panel displays, is being actively conducted. The organic light emitting display device is a self-luminous device and has various advantages such as brightness, driving voltage, and response speed, and no viewing angle dependency, compared to a liquid crystal display.

The light emitting mechanism of the organic EL device is as follows. Holes injected from the anode into the valence band or highest occupied molecular orbital (HOMO) of the hole injection layer (HIL) proceed to the emitting layer through the hole transporting layer (HTL). At the same time, electrons move from the cathode to the emission layer through the electron injection layer to combine with holes to form excitons. The exciton falls to the ground and emits light.

The organic light emitting diode has a wide viewing angle, high speed response, and high contrast, and thus can be used as a pixel of a television image display or a surface light source, and has been spotlighted as a next-generation display because of its thin, light, and good color. In addition, when a plastic substrate is employed, a curved element may be manufactured, and the element emitting white light may be used as a backlight of an organic EL device or a backlight of a liquid crystal display.

The structure of a conventional white organic light emitting display device is an anode layer 101 formed by vacuum deposition of indium tin oxide (ITO) on the transparent substrate 100, as shown in Figure 1, and the anode layer 101 Hole injection layer 102, hole transport layer 103, light emitting layers 104, 105, 106, hole block layer 107, electron transport layer 108, electron injection layer 109, cathode layer 110 It has a structure which vacuum-deposited.

In the organic light emitting device of FIG. 1, electrons are injected from the cathode layer 110, electrons are injected into the emission layers 104, 105, and 106 through the electron injection layer 109 and the electron transport layer 108, and the anode layer ( Holes injected from the 101 are injected into the light emitting layers 104, 105, and 106 through the hole injection layer 102 and the hole transport layer 103, and electrons and holes moved to the light emitting layers 104, 105, and 106, respectively. As the excitons of each of the light emitting layers formed in pairs and recombined, blue, green, and red light are emitted from each layer and mixed to emit white light.

In addition, another common white organic light emitting display device has a hetero multilayer structure including two light emitting layers using complementary colors of cyan, red, blue, and orange, or a mixture of hetero multilayers including three primary light emitting layers of blue, green, and red. It is manufactured using.

Another example structure using the above three wavelengths is an anode layer 121 formed by vacuum deposition of indium tin oxide (ITO) on the transparent substrate 120, as shown in Figure 2, and the anode layer ( The hole injection layer 122, the hole transport layer 123, the green light emitting layer 124, the red light emitting layer 125, the blue light emitting layer 127, the electron transport layer 128, the electron injection layer 129, the cathode layer (121) on the 121 130, and a vacuum vapor deposition is performed between the red light emitting layer and the blue light emitting layer in the order of the buffer layer 126.

However, conventionally known white organic light emitting diodes are difficult to obtain even distribution of red, green, and blue for white light required by LCD BLU (Back Light Unit) using two wavelengths of complementary colors, and have a short range of color coordinates. High efficiency full color display application It is difficult to satisfy the white light source, and also, the white organic electroluminescent device using three wavelengths was difficult to realize stable three wavelengths by energy transfer from blue to green or green to red. To this end, additional layers such as a hole block layer and a buffer layer are additionally formed in FIG. 1, but the results are not satisfactory and cause a dysfunction that complicates the structure.

In addition, the conventional white organic light emitting display device has a lot of problems in the lifespan and stability of the device because the emission spectrum is shifted to blue as the driving voltage increases.

The present invention is to solve the above problems,

As a simple structure, it aims at providing the white organic electroluminescent element which induces white light emission close to natural light, including a hybrid layer between two light emitting layers.

In addition, the light emitting materials of the two light emitting layers include a blue light emitting material and a yellow-red light emitting material, respectively, and have a wide band through the optimal composition ratio of the hybrid layer between the light emitting layers and the mixed layer. It is an object of the present invention to provide a white organic electroluminescent device which exhibits a light emitting area of and exhibits a continuous spectrum close to natural light, and is particularly applicable to LCD backlights, full-color light emitting devices, lighting fixtures, and next-generation flexible displays.

The present invention for achieving the above object,

In an organic light emitting display device comprising an anode layer, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer and a cathode layer, the light emitting layer is a first light emitting layer, a second light emitting layer and the first light emitting layer therebetween A hybrid layer formed by mixing and depositing a host material and a host material of the second light emitting layer, wherein a mixing weight ratio of the first light emitting layer and the second light emitting layer host material of the mixed layer is in a range of 33:67 to 67:33. An organic electroluminescent device is provided.

The present invention also provides an organic electroluminescent device comprising an anode layer, a light emitting layer, and a cathode layer, wherein the light emitting layer comprises a first light emitting layer, a second light emitting layer, and a host material of the first light emitting layer and a host of the second light emitting layer therebetween. Provided is a white organic electroluminescent device comprising a hybrid layer formed by mixing and depositing a material, and having a color reproducibility of 60% or more measured against NTSC color coordinates.

In addition, the thickness ratio of the first light emitting layer, the mixed layer, and the second light emitting layer provides a white organic light emitting device, characterized in that in the range of 1: 2.5: 3.5 to 1: 3.5: 4.5.

In addition, the second light emitting layer provides a white organic light emitting diode, characterized in that the light emitting material is contained 0.1 to 4% by weight based on the host material of the second light emitting layer.

Hereinafter, the present invention will be described in detail with reference to the drawings.

3 is a cross-sectional view illustrating a structure of a white organic light emitting display device according to an embodiment of the present invention.

As shown, an anode layer 11 formed on the transparent substrate 10, a hole injection layer 12, a hole transport layer 13, a first light emitting layer 14a, and a mixed layer 14c on the anode layer 11. And the second light emitting layer 14b, the electron transporting layer 15, the electron injection layer 16, and the cathode layer 17 are vacuum deposited in this order. In the above structure, the hole injection layer 12, the hole transport layer 13, the electron transport layer 15, and the electron injection layer 16 are provided to increase luminous efficiency, and some or all of them may be omitted as necessary. Included in

The anode layer 11 of the present invention is an electrode for injecting holes, and injects holes into the hole injection layer 12. Examples of the material for forming the anode layer 11 include, but are not limited to, metal oxides or metal nitrides such as ITO, IZO, tin oxide, zinc oxide, zinc aluminum oxide, and titanium nitride; Metals such as gold, platinum, silver, copper, aluminum, nickel, cobalt, lead, molybdenum, tungsten, tantalum and niobium; Alloys of these metals or alloys of copper iodides; Conductive polymers such as polyaniline, polythiopine, polypyrrole, polyphenylene vinylene, poly (3-methylthiopine), and polyphenylene sulfagard. The anode layer 11 may be formed of only one type of the above materials or may be formed of a mixture of a plurality of materials. In addition, a multilayer structure composed of a plurality of layers of the same composition or different compositions can be formed.

The material for forming the anode layer 11 preferably has a larger work function in order to easily inject holes. Chromium has a work function of 4.5 eV, nickel has a work function of 5.15 eV, gold has a work function of 5.1 eV, palladium has a work function of 5.55 eV, ITO has a work function of 4.8 eV, Copper has a work function of 4.65 eV. Although the work function of the surface which contacts the hole injection layer 12 of the anode layer 11 is not restrict | limited, It is preferable that it is 4 eV or more.

When the anode layer 11 is disposed on the light extraction end from the light emitting layer, the transmittance for the light to be extracted is preferably not less than 10%. When the light emitted from the light emitting layer is in the visible light region, ITO is preferable for forming the anode layer 11 because it has a high transmittance in the visible light region.

The hole injection layer 12 of the present invention may use materials known in the art, but is not limited to PEDOT / PSS or copper phthalocyanine (CuPc), 4,4 ', 4 "-tris (3-methylphenylphenylamino) A material such as triphenylamine (m-MTDATA) is formed to a thickness of 5 nm to 40 nm.

The hole transport layer 13 of the present invention may use materials known in the art, but is not limited to 4,4'-bis [N- (1-naphthyl) -N-phenyl-amino] -biphenyl (NPD ) Or N, N'-diphenyl-N, N'-bis (3-methylphenyl) -1,1'-biphenyl-4,4'-diamine (TPD) to form a thickness of 20 to 60 nm. .

One of the first light emitting layer 14a and the second light emitting layer 14b of the present invention is a blue light emitting layer, and the other layer is a yellow-red light emitting layer. Here, the yellow-red light-emitting layer means that the emission spectrum of the yellow and red regions is relatively distributed than the other regions and emits light. The present invention implements white color by mixing colors emitted from the first light emitting layer and the second light emitting layer. Hereinafter, for convenience of description, a case in which the first light emitting layer is a blue light emitting layer and the second light emitting layer is a yellow-red light emitting layer will be described with an example. Those skilled in the art through the following description, it is easily understood that the description of the case where the first light emitting layer is a yellow-red light emitting layer and the second light emitting layer is a blue light emitting layer can be easily understood and the present invention. It can be seen that it is included.

The first light emitting layer 14a of the present invention may be a blue light emitting layer. Blue light emitting layer materials known in the art may be used, and preferably, as a host, (4,4′-bis (2,2-diphenyl-ethen-1-yl) diphenyl (DPVBi), bis (styryl) Amine (DSA) systems (e.g. DPVDPAN), bis (2-methyl-8-quinolinolato) (triphenylsiloxy) aluminum (III) (SAlq), bis (2-methyl-8-quinolinola SAT) (para-phenolato) aluminum (III) (BAlq), bis (salen) zinc (II), 1,3-bis [4- (N, N-dimethylamino) phenyl-1,3,4-oxa Diazoyl] benzene (OXD8), 3- (biphenyl-4-yl) -5- (4-dimethylamino) 4- (4-ethylphenyl) -1,2,4-triazole (p-EtTAZ), 3- (4-biphenyl) -4-phenyl-5- (4-tert-butylphenyl) -1,2,4-triazole (TAZ), 2,2 ', 7,7'-tetrakis ( Bi-phenyl-4-yl) -9,9'-spirofluorene (Spiro-DPVBI), tris (para-ter-phenyl-4-yl) amine (p-TTA), 5,5-bis (dimethage) Tilboryl) -2,2-bitiophene (BMB-2T), perylene, and the like, and (4,4'-bis (2,2-diphenyl-ethen-1-yl) diphenyl ( DPVBi), bis (styryl) amine ( DSA) system is preferred Dopants may be omitted or optionally added, but are not limited to those listed as host materials above.

The second light emitting layer 14b of the present invention may be a yellow-red light emitting layer. Yellow-red light emitting layer materials known in the art may be used, including but not limited to tris (8-quinolinato) aluminum (III) (Alq3), Almq3 (tris (4-methyl-8-quinolinolato) aluminum (III)) Quinacridone, DCM1 (4-dicyanomethylene-2-methyl-6- (para-dimethylaminostyryl) -4H-pyran), DCM2 (4-dicyanomethylene-2-methyl-6- (Julolidin-4-yl-vinyl) -4H-pyran), DCJT (4- (dicyanomethylene) -2-methyl-6- (1,1,7,7-tetramethyljulolidyl-9- Enyl) -4H-pyran), DCJTB (4- (dicyanomethylene) -2-tertarybutyl-6- (1,1,7,7-tetramethylzololidyl-9-enyl) -4H-pyran) , DCJTI (4-dicyanomethylene) -2-isopropyl-6- (1,1,7,7-tetramethylzololidyl-9-enyl) -4H-pyran) and nile red, ru Rubrene and the like can be used as a host or dopant, preferably tris (8-quinolinato) aluminum (III) (Alq3) as a host, and DCJTB (4- (dicyanomethylene) -2-ter as the dopant. Sherry Butyl-6- (1,1,7,7- tetramethyl-line Lowry dill-9-enyl) -4H- pyran), or may be a rubrene (Rubrene).

The second light emitting layer may implement a white that is closer to natural light, when the dopant is included in an amount of 0.1 to 4% by weight based on the host material of the second light emitting layer.

The mixed layer 14c of the present invention is characterized in that white color close to natural light is realized by mixing the host material of the first light emitting layer 14a and the host material of the second light emitting layer 14b in a specific composition ratio. The mixing ratio of the host material of the first light emitting layer and the host material of the second light emitting layer constituting the mixed layer is preferably in the range of 33:67 to 67:33. Beyond the above range is far from white, which is close to natural light.

As the material for forming the mixed layer 14c, any host material of the first light emitting layer, that is, a host material that can be used in the blue light emitting layer and used in the first light emitting layer can be used without limitation. It is possible to use the same material as the material constituting the first light emitting layer, or to use a material in which the light emitting region includes the absorption region of the blue light emitting material, but is not limited thereto (4,4'-bis (2,2-di). Phenyl-ethen-1-yl) diphenyl (DPVBi) and bis (styryl) amine (DSA) systems are preferred.

In addition, as a material for forming the mixed layer, any host material of the second light emitting layer, that is, a host material that can be used in the yellow-red light emitting layer and used in the second light emitting layer, can be used without limitation. The same material as the material constituting the second light emitting layer is used, or the light emitting area is tris (8-quinolinato) aluminum (III) (Alq3), Almq3 (tris (4-methyl-8-quinolinolato) aluminum ( III)) or the use of a material comprising an absorption region of a red light emitting material, such as quinacridone, is possible, but not limited to, tris (8-quinolinato) aluminum (III) (Alq3).

In forming the first light emitting layer, the mixed layer, and the second light emitting layer, the thickness ratio is preferably 1: 2.5: 3.5 to 1: 3.5: 4.5 in the range of natural light.

The electron transport layer 15 of the present invention may use materials known in the art, including but not limited to aryl substituted oxadiazoles, aryl-substituted triazoles, aryl-substituted phenanthrolines, benzoxazoles, or benzs Cyanazole compounds, for example 1,3-bis (N, Nt-butyl-phenyl) -1,3,4-oxadiazole (OXD-7); 3-phenyl-4- (1'-naphthyl) -5-phenyl-1,2,4-triazole (TAZ); 2,9-dimethyl-4,7-diphenyl-phenanthroline (vasocuproin or BCP); Bis (2- (2-hydroxyphenyl) -benzoxazolate) zinc; Or bis (2- (2-hydroxyphenyl) -benziazolate) zinc; As the electron transporting material, (4-biphenyl) (4-t-butylphenyl) oxydiazole (PDB) and tris (8-quinolinato) aluminum (III) (Alq3) can be used, preferably Tris ( Preference is given to 8-quinolinato) aluminum (III) (Alq3).

The electron injection layer 16 and the cathode layer 17 of the present invention may use a material known in the art, but is not limited to LiF as an electron injection layer and has a low work function such as Al, Ca, Mg, Ag, etc. Metal may be used as the cathode layer 200, and preferably Al.

4A and 4B are schematic views of the color filter 20 and the assembly used for the evaluation of the organic electroluminescent device according to the present invention.

The illustrated color filter is manufactured by applying and patterning a black matrix and a color resist resin on a transparent substrate, and the construction and materials of the color filter are well known in the art, and thus detailed description thereof will be omitted.

The present invention will be described in more detail with reference to the following examples. Embodiments of the present invention are only specific examples, and are not intended to limit or limit the protection scope of the present invention.

Example 1

Fabrication of White Organic Light Emitting Diode (WOLED 1)

Patterning is performed using lithography as a unit device on a substrate on which a positive electrode material (ITO) is deposited on a glass substrate.

The patterned unit substrate is pretreated with acetone, detergent, distilled water and isopropyl alcohol.

The cleaned unit substrate is transferred to an organic chamber after UV / O ₃ cleaning and plasma treatment. Plasma is performed using oxygen (O ₂ ).

Inside the organic chamber, the surface-treated substrate is m-MTDATA, the hole injection layer, 50 nm thick, NPD, the hole transport layer 20 nm thick, DPVDPAN, the first light emitting layer 5 nm thick, and the mixed layer The second light emitting layer is made of Alq3, which is a host material of the second light emitting layer, and a dopant material, butobune, at a concentration of 2% and a thickness of 20 nm so that the light emitting layer host material and the second light emitting layer host material are 15 nm in a mixed weight ratio of 1: 1. Then, Alq3, which is an electron transport layer, is deposited to have a thickness of 20 nm.

After deposition of the organic layer is transferred to the metal chamber, the cathode layer is deposited.

After the deposition of the organic light emitting device component layer is completed, the device is completed by encapsulating in the glove box.

Example 2

Fabrication of White Organic Light Emitting Diode (WOLED 2)

In the light emitting layer, the mixed layer is formed by depositing the first light emitting layer host material and the second light emitting layer host material in a mixed weight ratio of 1: 2 so as to be 15 nm, thereby fabricating a device in the same manner as in Example 1.

Example 3

Fabrication of White Organic Light Emitting Diode (WOLED 3)

In the light emitting layer, the mixed layer is formed by depositing the first light emitting layer host material and the second light emitting layer host material so as to be 15 nm in a 2: 1 mixed weight ratio, and fabricating the device in the same manner as in Example 1 above.

Example 4

Fabrication of White Organic Light Emitting Diode (WOLED 4)

In the light emitting layer, the second light emitting layer was fabricated in the same manner as in Example 1, except that Alq3, a host material of the second light emitting layer, and rubrene, a dopant material, were deposited at a concentration of 1% and a thickness of 20 nm. do.

Example 5

Fabrication of White Organic Light Emitting Diode (WOLED 5)

In the light emitting layer, the second light emitting layer was fabricated in the same manner as in Example 1, except that Alq3, a host material of the second light emitting layer, and rubrene, a dopant material, were deposited at a concentration of 4% and a thickness of 20 nm. do.

Comparative Example 1

After patterning and pretreatment were performed in the same manner as in Example 1, CuPc was vacuum deposited on the upper portion to form a hole injection layer having a thickness of 100 μs. Subsequently, NPD is vacuum deposited on the hole injection layer to form a hole transport layer having a thickness of 400 kHz. Thereafter, Alq3 was vacuum deposited on the hole transport layer to form a green light emitting layer having a thickness of 180 kHz. Subsequently, NPD and rubrene are vacuum deposited on the green light emitting layer in the same manner to form a red light emitting layer having a thickness of 120 Å. At this time, the content of NPD is 97% by weight, the content of rubrene is 3.0% by weight. Next, NPD is vacuum-deposited on the red light-emitting layer to form a white control layer capable of controlling the distribution of excitons. The thickness of the formed white adjusting layer is 22 kPa. DPVBi is vacuum deposited on the white control layer to form a blue light emitting layer, and Alq3 is vacuum deposited on the blue light emitting layer to form an electron transport layer. The thickness formed at this time is 180 kPa of the blue light emitting layer and 120 kPa of the electron transporting layer. Next, LiF is vacuum-deposited on the electron transport layer to form a 10 Å thick LiF electron injection layer, and Al is vacuum deposited on the LiF electron injection layer to form an Al layer with a thickness of 1000 Å to form a cathode layer. In the organic electroluminescent device manufactured in this manner, part of the organic light emitting device emits light from the blue light emitting layer made of DPVBi due to the electron blocking effect formed by forming a white control layer between the red light emitting layer and the blue light emitting layer, and part of the light emitting layer of the red light emitting layer doped with rubrene Orange-red light is emitted, and the rest contributes to green light emission in the green light emitting layer by the exciton-trapping structure.

Comparative Example 2

In Comparative Example 1, an organic electroluminescent device was manufactured according to the same method as Comparative Example 1, except that the thickness of the white adjusting layer was changed to 17 GPa in order to adjust color purity. Therefore, in Comparative Example 2, some excitons contribute to yellow-orange emission by the rubrene of the red light emitting layer, and color excitation is adjusted by changing the thickness of the white control layer to contribute the remaining excitons to blue and green light emission.

[Production of color filter]

On a 50 mm × 50 mm × 0.7 mm support substrate (transparent substrate), BK0800H (made by Cheil Industries) was spin-coated as a material of the black matrix (BM), ultraviolet-exposed through a photomask which becomes the pattern of FIG. 4B, and 0.043% alkali metal After developing with an aqueous hydroxide solution, the solution was baked at 220 ° C. to form a pattern of a black matrix (film thickness of 1.5 μm).

Next, as a material of the blue color filter, YB-766 (Dongwoo Fine Chem) containing copper phthalocyanine-based pigment is spin-coated and positioned on BM through a photo mask that can obtain four square (18 mm X 18 mm) patterns. The film was exposed to ultraviolet light, developed with a 2.38% TMAH aqueous solution, and baked at 220 ° C. to form a pattern of a blue color filter (film thickness of 1.5 μm).

Next, as a material of the green color filter, YG-766 (product of Dongwoo Fine Chem) containing a brominated phthalocyanine-based azo pigment was spin coated, and 4 square patterns (18mmX18mm) were applied to the BM through a photo mask. Position matching was performed, followed by ultraviolet exposure, development with a 2.38% aqueous TMAH solution, and baking at 220 ° C. to form a pattern of a green color filter (film thickness of 1.5 μm) next to the blue color filter.

Next, as a material of the red color filter, YR-766 (Dongwoo Fine-Chem) containing Dyketopyrrolopiat azo pigment was spin-coated, and a photo mask capable of obtaining four square (18 mm X 18 mm) patterns was obtained. Positionally matched to BM through UV exposure, and developed with a 2.38% TMAH aqueous solution and then baked at 220 ℃ to form a pattern of a red color filter (film thickness 1.5μm) between the blue color filter and the green color filter.

[Evaluation of the device]

The device obtained through the above Examples and Comparative Examples was measured.

Luminous efficiency, power efficiency, and color coordinates were measured using a colorimeter (Minolta CS-100A), a power supply, and a jig (manufactured by McScience).

Measurement was measured by increases from 2.5mA to ^{2.5mA / cm 2 100mA / cm 2} , results Results are at 10mA / cm ^2.

The measurement results are shown in Table 1 and FIGS. 5 to 7. As shown in the figure, the device according to the present invention has a characteristic of having high color reproducibility (about 60% or more) as compared with NTSC color coordinates as a result of assembling with a self-made color filter by emitting white light close to natural light have.

TABLE 1

Luminous Efficiency (cd / A) ^a Power Efficiency (lm / W) ^a Color coordinates (x, y) ^b Example 1 4.45 1.77 (0.29, 0.33) Example 2 4.89 1.86 (0.27, 0.34) Example 3 5.15 1.89 (0.30, 0.26) Example 4 4.49 1.64 (0.22, 0.30) Example 5 3.52 1.08 (0.29, 0.37) Comparative Example 1 1.70 0.50 (0.39, 0.52) Comparative Example 2 2.80 0.90 (0.40, 0.53)

a: measured at 10 mA / cm ²

b: measured at 50 mA / cm ²

The device according to the present invention exhibited high color reproducibility of more than 60% as measured by assembly with a self-manufactured color filter by white light emission close to natural light. Color reproducibility of 60% or more is a value that is difficult to achieve in conventional organic light emitting devices, which exceeds the color reproducibility of currently used portable devices.

In addition, the structure can be simplified, and when applied to the actual display, it can take advantage of the economic advantages through the simplification of the process and the simplification of the material. Using this, it can be applied to a real display quickly and can use infrastructure such as LCD production line as it is.

Claims (4)

In an organic light emitting display device comprising an anode layer, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer and a cathode layer, the light emitting layer is a first light emitting layer, a second light emitting layer and the first light emitting layer therebetween A hybrid layer formed by mixing and depositing a host material and a host material of the second light emitting layer, wherein a mixing weight ratio of the first light emitting layer and the second light emitting layer host material of the mixed layer is in a range of 33:67 to 67:33. Organic electroluminescent device. In an organic light emitting device comprising an anode layer, a light emitting layer, and a cathode layer, the light emitting layer is a mixture of the first light emitting layer, the second light emitting layer and the host material of the first light emitting layer and the host material of the second light emitting layer therebetween A white organic electroluminescent device comprising a formed hybrid layer and having a color reproducibility of at least 60% measured against NTSC color coordinates. The white organic electroluminescent device according to claim 1 or 2, wherein the thickness ratio of the first light emitting layer, the mixed layer, and the second light emitting layer is in the range of 1: 2.5: 3.5 to 1: 3.5: 4.5. The white organic electroluminescent device according to claim 1 or 2, wherein the second light emitting layer comprises 0.1 to 4 wt% of a light emitting material based on the host material of the second light emitting layer.

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