KR20220030239A - White organic light emitting device - Google Patents

Abstract

The present invention is to provide a white organic light emitting device capable of improving device lifespan. According to an embodiment of the present invention, a white organic light emitting device comprises: a first light emitting unit, disposed between a first electrode and a second electrode, which includes a first light emitting layer having a peak wavelength of 440 nm to 480 nm; a second light emitting unit disposed on the first light emitting unit and including a second light emitting layer having a peak wavelength of 600 nm to 650 nm, a third light emitting layer having a peak wavelength of 510 nm to 580 nm, and a fourth light emitting layer; and a charge generation layer between the first light emitting unit and the second light emitting unit.

Description

White organic light emitting device {WHITE ORGANIC LIGHT EMITTING DEVICE}

The present invention relates to an organic light emitting device, and more particularly, to a white organic light emitting device capable of improving the device lifespan.

Recently, as we enter the information age, the field of display that visually expresses electrical information signals has developed rapidly. device) is being developed.

Specific examples of such a flat panel display device include a liquid crystal display device (LCD), a plasma display panel device (PDP), a field emission display device (FED), and an organic light emitting display device. (Organic Light Emitting Device: OLED) etc. are mentioned.

In particular, as a self-luminous device, an organic light emitting diode display has advantages in that it has a fast response speed, luminous efficiency, luminance, and viewing angle compared to other flat panel display devices.

In the organic light emitting diode display, an organic light emitting layer is formed between two electrodes. Electrons and holes are respectively injected from the two electrodes into the organic light emitting layer to generate excitons according to the combination of electrons and holes. And, it is a device using the principle that light is generated when the generated exciton falls from an excited state to a ground state.

A conventional organic light emitting diode display includes a blue light emitting layer made of a blue fluorescent material to realize white color. However, the light emitting layer made of a fluorescent material has a theoretical quantum efficiency of about 25% compared to the light emitting layer made of a phosphorescent material. For this reason, there is a problem in that the blue light emitting layer made of the fluorescent material does not provide sufficient luminance compared to the phosphor material.

White organic light emitting device (Patent Application No. 10-2007-0053472)

Conventional organic light emitting devices have limitations in light emitting characteristics and lifespan performance due to the material and device structure of the organic light emitting layer. Accordingly, various methods for improving the lifespan of white organic light emitting devices have been proposed.

As one method, there is a method of using the light emitting layer as a single layer. In this method, a white organic light emitting device can be manufactured by using a single material or by doping two or more materials. For example, there is a method in which red and green dopants are used in a blue host, or red, green, and blue dopants are added and used in a host material having a large band gap energy. However, this method has problems in that energy transfer to the dopant is incomplete and it is difficult to control the white balance.

In addition, there is a limit to the components of the dopant included in the light emitting layer due to the characteristics of the dopant itself. In addition, when each light emitting layer is mixed, the focus is on the realization of white light, so that the wavelength characteristic having an emitting peak value at a wavelength other than red, green, and blue is shown. do. Accordingly, there is a problem in that the color reproducibility is deteriorated when the color filter is included. In addition, since the lifespan of the dopant material is different, color shift occurs during continuous use.

Alternatively, two light emitting layers having a complementary color relationship may be stacked to emit white light. However, in this structure, when white light passes through the color filter, a difference occurs between the peak wavelength region of each light emitting layer and the transmission region of the color filter. Accordingly, since the range of colors that can be expressed is narrowed, there may be difficulties in realizing a desired color gamut.

For example, when the blue light emitting layer and the yellow light emitting layer are stacked, white light is emitted while peak wavelengths are formed in the blue wavelength region and the yellow wavelength region. When the white light passes through the red, green, and blue color filters, respectively, the transmittance of the blue wavelength region is lower than that of the red or green wavelength region, so that luminous efficiency and color reproducibility are lowered.

In addition, the luminous efficiency of the yellow phosphorescent layer is relatively higher than that of the blue fluorescent layer, and thus panel efficiency and color reproducibility are reduced due to the difference in efficiency between the phosphorescent layer and the fluorescent layer. In addition, there is a problem that the luminance of blue is relatively lower than that of yellow.

In addition to this structure, in the case of a structure in which a blue fluorescent light-emitting layer and a green-red phosphorescent light-emitting layer are stacked, there is a problem in that the luminance of blue is relatively lower than that of green-red.

As mentioned above, various methods have been proposed to improve the lifetime of the device. However, a structure in which the number of light emitting units constituting the light emitting layers is increased causes an increase in manufacturing cost according to an increase in processes and a problem in that a driving voltage is increased because the thickness of the device is increased.

Accordingly, the inventors of the present invention recognized the above-mentioned problems, and conducted various experiments to improve device lifespan by configuring two or more light emitting layers in one light emitting unit without increasing the number of light emitting units constituting the light emitting layers. .

Accordingly, the inventors of the present invention invented a white organic light emitting device having a new structure in which device lifespan can be improved by configuring two or more light emitting layers in one light emitting unit through various experiments.

A problem to be solved according to an embodiment of the present invention is to configure two or more light emitting layers in one light emitting part and further configure a light emitting area control layer capable of evenly distributing the light emitting area, thereby improving the device lifespan. To provide a light emitting device.

A white organic light emitting device according to an embodiment of the present invention includes a first light emitting part between a first electrode and a second electrode, and a second light emitting part on the first light emitting part. According to an embodiment of the present invention, at least one of the first light emitting unit and the second light emitting unit includes a light emitting region control layer, thereby providing a white organic light emitting device capable of improving device lifespan.

A white organic light emitting diode according to another embodiment of the present invention includes a first light emitting part between a first electrode and a second electrode, a second light emitting part on the first light emitting part, and a third light emitting part on the second light emitting part. is composed At least one of the first light emitting unit, the second light emitting unit, and the third light emitting unit is configured as a light emitting region control layer, thereby providing a white organic light emitting device capable of improving device lifespan.

Details of other embodiments are included in the detailed description and drawings.

By configuring the light emitting area control layer capable of evenly distributing the light emitting area of the light emitting unit according to the embodiment of the present invention, there is an effect of improving the device lifespan.

In addition, there is an effect of improving the reliability of the device by preventing the deterioration of the light emitting layer.

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

Since the contents of the invention described in the problems to be solved above, the means for solving the problems, and the effects do not specify the essential characteristics of the claims, the scope of the claims is not limited by the matters described in the contents of the invention.

1 is a view showing a white organic light emitting diode according to an embodiment of the present invention.
2 is a diagram illustrating an energy band diagram of a light emitting unit according to an embodiment of the present invention.
3 is a diagram illustrating a white organic light emitting diode according to another exemplary embodiment of the present invention.
4 is a diagram illustrating an energy band diagram of a light emitting unit according to another embodiment of the present invention.
FIG. 5A is a view showing the light emission intensity of the light emitting unit according to another embodiment of the present invention, and FIG. 5B is a view showing the light emitting area of the light emitting unit according to another embodiment of the present invention.
6 is a view showing a white organic light emitting diode according to another embodiment of the present invention.
7 is a diagram illustrating a white organic light emitting diode according to another embodiment of the present invention.
8 is a view showing emission intensity of a white organic light emitting diode according to a comparative example and an embodiment of the present invention.
9 is a view showing a white organic light emitting diode according to another embodiment of the present invention.
10 is a diagram illustrating a white organic light emitting diode according to another embodiment of the present invention.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention belongs It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims.

The shapes, sizes, proportions, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of the present invention are illustrative and the present invention is not limited to the illustrated matters. Like reference numerals refer to like elements throughout. In addition, in describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. When 'including', 'having', 'consisting', etc. mentioned in this specification are used, other parts may be added unless 'only' is used. When a component is expressed in the singular, cases including the plural are included unless otherwise explicitly stated.

In interpreting the components, it is construed as including an error range even if there is no separate explicit description.

In the case of a description of the positional relationship, for example, when the positional relationship of two parts is described as 'on', 'on', 'on', 'beside', etc., 'right' Alternatively, one or more other parts may be positioned between two parts unless 'directly' is used.

In the case of a description of a temporal relationship, for example, 'immediately' or 'directly' when a temporal relationship is described with 'after', 'following', 'after', 'before', etc. It may include cases that are not continuous unless this is used.

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

Each feature of the various embodiments of the present invention can be partially or wholly combined or combined with each other, technically various interlocking and driving are possible, and each of the embodiments may be independently implemented with respect to each other or implemented together in a related relationship. may be

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings and examples.

1 is a view showing a white organic light emitting diode according to an embodiment of the present invention.

The white organic light emitting diode 100 illustrated in FIG. 1 includes a first electrode 102 and a second electrode 104 , and a first light emitting unit 110 and a second light emitting unit between the first and second electrodes 102 and 104 . A portion 120 is provided.

The first electrode 102 is an anode for supplying holes, and may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), etc. which are transparent conductive materials such as transparent conductive oxide (TCO), but must be It is not limited.

The second electrode 104 is a cathode for supplying electrons, and is formed of a metallic material such as gold (Au), silver (Ag), aluminum (Al), molybdenum (Mo), magnesium (Mg), or the like. It may be formed of an alloy, but is not necessarily limited thereto.

The first electrode 102 and the second electrode 104 may be referred to as an anode or a cathode, respectively.

The first electrode 102 may be a transmissive electrode, and the second electrode 104 may be a reflective electrode. Also, the first electrode 102 may be a reflective electrode, and the second electrode 104 may be a transflective electrode.

The first light emitting unit 110 includes a first hole transporting layer (HTL) 112, a first emitting layer (EML) 114, a first electron transporting layer (HTL) on the first electrode 102. It may include an Electron Transporting Layer (ETL) 116 .

Although not shown in the drawings, a hole injection layer (HIL) may be additionally configured. The hole injection layer HIL is formed on the first electrode 102 and serves to smoothly inject holes from the first electrode 102 . The first hole transport layer (HTL) 112 supplies holes from the hole injection layer (HIL) to the first emission layer (EML) 114 . The first electron transport layer (ETL) 116 supplies electrons from the second electrode 104 to the first emission layer (EML) 114 .

The hole injection layer (HIL) is made of MTDATA (4,4',4"-tris(3-methylphenylphenylamino)triphenylamine), CuPc (copper phthalocyanine), or PEDOT/PSS (poly(3,4-ethylenedioxythiphene, polystyrene sulfonate), etc.). may be made, but is not necessarily limited thereto.

In the first light emitting layer (EML) 114 , holes supplied through the hole transport layer (HIL) and electrons supplied through the electron transport layer (ETL) 116 are recombined to generate light.

The first hole transport layer (HTL) 112 may be made of the same material as the second hole transport layer (HTL) 122 , but is not limited thereto.

The first hole transport layer (HTL) 112 may be formed by applying two or more layers or two or more materials.

The first electron transport layer (ETL) 116 may be made of the same material as the second electron transport layer (ETL) 126 , but is not limited thereto.

The first electron transport layer (ETL) 116 may be formed by applying two or more layers or two or more materials.

The first light emitting layer (EML) 114 includes a blue light emitting layer or a red-blue light emitting layer. A peak wavelength of the emission region of the blue emission layer may be in a range of 440 nm to 480 nm. A peak wavelength of the emission region of the red-blue emission layer may be in a range of 600 nm to 650 nm.

A first charge generating layer (CGL) 140 may be further formed between the first light emitting unit 110 and the second light emitting unit 120 . The first charge generation layer (CGL) 140 adjusts the charge balance between the first light emitting unit 110 and the second light emitting unit 120 . The charge generation layer 140 may include an N-type charge generation layer (N-CGL) and a P-type charge generation layer (P-CGL).

The N-type charge generation layer (N-CGL) may be formed of an organic layer doped with an alkali metal such as Li, Na, K, or Cs, or an alkaline earth metal such as Mg, Sr, Ba, or Ra, respectively, but it must be It is not limited.

Each of the P-type charge generation layers (P-CGL) may be formed of an organic layer including a P-type dopant, but is not limited thereto. In addition, the first charge generating layer (CGL) 140 may be formed as a single layer.

The second light emitting part 120 includes a second hole transporting layer (HTL) 122 , a second emitting layer (EML) 124 , and a second electron transporting layer (ETL) 126 . ) can be included. Although not shown in the drawings, an electron injection layer (EIL) may be additionally formed on the second electron transport layer (ETL) 126 . In addition, a hole injection layer (HIL) may be additionally configured.

The second hole transport layer (HTL) 122 may be made of the same material as the first hole transport layer (HTL) 112 , but is not limited thereto.

The second hole transport layer (HTL) 122 may be formed by applying two or more layers or two or more materials.

The second electron transport layer (ETL) 126 may be made of the same material as the first electron transport layer (ETL) 116 , but is not limited thereto.

The second electron transport layer (ETL) 126 may be formed by applying two or more layers or two or more materials.

The first light emitting layer (EML) 124 of the second light emitting unit 120 is formed of a yellow-green light emitting layer. A peak wavelength of the emission region of the yellow-green emission layer may be in the range of 510 nm to 580 nm.

In this structure, the first light emitting layer (EML) 124 of the second light emitting unit 120 is a yellow-green light emitting layer and needs to emit both green and red regions, so that red (Red) The luminous efficiency of the light emitting layer is lower than that of the green (Green). Therefore, in order to improve the luminous efficiency of the red light emitting layer, a red light emitting layer is further configured as the second light emitting layer (EML) 125 .

2 is a diagram illustrating an energy band diagram of a light emitting unit according to an embodiment of the present invention.

That is, when two light emitting layers are formed in the second light emitting unit 120 , an energy band diagram is shown.

The second light-emitting unit 120 includes two light-emitting layers, a first light-emitting layer (EML) 124 of the second light-emitting unit 120, a yellow-green light-emitting layer, and a second light-emitting layer (EML) ( 125) of a red light emitting layer.

In this configuration, the peak wavelength of the light emitting region of the red light emitting layer is in the range of 600 nm to 650 nm, and the peak wavelength of the light emitting region of the yellow-green light emitting layer is 510 nm to 580 nm. Since the red light emitting layer and the light emitting area of the yellow-green light emitting layer are close to each other, aggregation of the light emitting area of the red and yellow-green light emitting layers occurs. As a result, the emission region is biased toward one of the red or yellow-green emission layers. Accordingly, deterioration in the second light emitting unit 120 is accelerated, and the device lifespan is reduced. In addition, there is a problem in that a desired color cannot be realized at a peak wavelength of a desired light emitting region.

In order to solve the above problems, the inventors of the present invention can improve the aggregation phenomenon of the light emitting area that occurs in a structure including at least two light emitting layers in one light emitting part, maximize the light emitting area and evenly distribute the light emitting area. structure was invented.

That is, by configuring at least two light emitting layers in one light emitting part and further comprising a light emitting region control layer capable of evenly distributing the light emitting area, a structure capable of improving the device lifespan was invented.

3 is a diagram illustrating a white organic light emitting diode according to another exemplary embodiment of the present invention.

In describing the present embodiment, a description of the same or corresponding components as in the previous embodiment will be omitted.

The white organic light emitting diode 200 of FIG. 3 includes a first electrode 102 and a second electrode 104 , and a first light emitting unit 110 and a second light emitting unit between the first and second electrodes 102 and 104 . (120) is provided.

Two light emitting layers and an Emission Area Control Layer (EACL) 190 are formed in the second light emitting unit 120 . the second The first light emitting layer (EML) 124 of the light emitting unit 120 is composed of a yellow-green light emitting layer, and the second light emitting layer (EML) 125 is composed of a red light emitting layer. Then, a yellow-green light emitting layer is constituted by the light emitting area control layer (EACL) 190 .

A peak wavelength of the emission region of the yellow-green emission layer that is the first emission layer (EML) 124 of the second emission unit 120 may be in the range of 510 nm to 580 nm. . A peak wavelength of the emission region of the red emission layer, which is the second emission layer (EML) 125 , may be in a range of 600 nm to 650 nm.

A peak wavelength of the emission region of the yellow-green emission layer that is the emission region control layer (EACL) 190 may be in a range of 510 nm to 580 nm.

In addition, the white organic light emitting diode according to another embodiment of the present invention may be applied to a bottom emission method, a top emission method, or a positive emission method.

4 is a diagram illustrating an energy band diagram of a light emitting unit according to another embodiment of the present invention.

In the drawings, the first light emitting layer (EML) 124 and the second light emitting layer (EML) 125 of the second light emitting part 120 are illustrated as one dopant and one host, but a hole in one dopant ) may be composed of two hosts consisting of a host and an electron host. When two hosts are included in one dopant, the efficiency or lifetime of the emission layer may be improved, but the present invention is not limited thereto.

In addition, although the figure shows the light emitting area control layer (EACL) 190 as one dopant and one host, it may be composed of two hosts including a hole host and an electron host in one dopant. there is. When two hosts are included in one dopant, the efficiency or lifetime of the emission layer may be improved, but the present invention is not limited thereto.

The first emission layer (EML) 124 and the emission area control layer (EACL) 190 of the second light emitting unit 120 will be described, taking the case where one dopant includes two hosts as an example. A hole moves from a hole host of the first emission layer (EML) 124 to a hole host of the emission area control layer (EACL) 190 . Electrons move from the electron host of the first emission layer (EML) 124 to the electron host of the emission region control layer (EACL) 190 , and become excitons in which the moved holes and electrons are combined to form a light emitting part light is generated inside.

A dopant constituting a yellow-green light emitting layer which is the first light emitting layer (EML) 124 and a dopant constituting a yellow-green light emitting layer which is the light emitting area control layer (EACL) 190 can be configured in the same way. And the host constituting the yellow-green light emitting layer which is the first light emitting layer (EML) 124 is the host constituting the yellow-green light emitting layer which is the light emitting area control layer (EACL) 190 . can be configured differently. However, the present invention is not necessarily limited thereto. The host may be composed of two hosts in addition to one, a hole host and a charge host. It is preferable that the hole mobility of the host included in the emission area control layer (EACL) 190 is faster than that of the host of the first emission layer (EML) 124 . For example, the hole mobility of the emission area control layer (EACL) 190 is preferably faster than 1×10 −5 cm 2 /Vs. This makes the generation of excitons in the emission region control layer (EACL) 190 faster than excitons generated in the first emission layer (EML) 124, so that the first emission layer (EML) 124 . It is possible to move an exciton away from the second light emitting layer (EML) 125 .

As shown in FIG. 4 , the density of excitons generated in the first emission layer (EML) 124 and the second emission layer (EML) 125 is reduced by the emission region control layer (EACL) 190 . will make it Accordingly, the distribution of excitons in the first emission layer (EML) 124 is moved away from the second emission layer (EML) 125 by the emission area control layer (EACL) 190 . Accordingly, the light emitting area of the first light emitting layer (EML) 124 and the second light emitting layer (EML) 125 are separated to improve aggregation of the light emitting area, and deterioration in the second light emitting part 120 is improved. it will slow down

Accordingly, since the light emitting area is evenly distributed in the second light emitting part 120 , deterioration in the second light emitting part 120 can be reduced and the lifetime of the device can be improved by inducing an increase in lifespan.

FIG. 5A is a view showing the light emission intensity of the light emitting unit according to another embodiment of the present invention, and FIG. 5B is a view showing the light emitting area of the light emitting unit according to another embodiment of the present invention.

That is, FIGS. 5A and 5B are diagrams showing the light emitting area and the light emitting intensity of the light emitting part as a result of an experiment confirming the light emitting area of the light emitting area control layer in another embodiment of the present invention.

In order to check whether the light emitting area control layer (EACL) 190 of the present invention contributes to the improvement of lifespan, the inventors constructed several devices and repeated various experiments. As a result of repeated experiments, the device shown in Table 1 below was constructed. Through this experiment, it was confirmed that when at least two or more light emitting layers are formed in one light emitting part, it is effective in improving the lifespan without affecting the device characteristics.

Each of the devices for this experiment consisted of 8 devices, and the configuration of the devices is shown in Table 1 below.

In this experiment, the device should be configured with the first light emitting layer (EML) 124 , the second light emitting layer (EML) 125 and the light emitting area control layer (EACL) 190 of the second light emitting unit 120 . However, as shown in Table 1, any light emitting layer except for the second light emitting layer (EML) 125 is formed between the first light emitting layers (EML) 124 . The reason is that the energy of the red light emitting layer which is the second light emitting layer (EML) 125 is higher than that of the yellow-green light emitting layer which is the first light emitting layer (EML) 124 , so the high energy This is because it is displayed in red. Accordingly, in order to check the emission area and the emission intensity of the emission area control layer 190, the device is configured as shown in Table 1 above. In addition, the light emitting area and light emission intensity of the red light emitting layer, which is an arbitrary light emitting layer, were confirmed.

In Table 1, devices 1 to 3 are composed of a first light emitting layer, a light emitting layer, and a light emitting region control layer. The first light emitting layer is expressed as the first light emitting layer 1 to the first light emitting layer 4 according to the thickness.

The first light emitting layer 1 of the device 1 is a yellow-green light emitting layer and has a thickness of 20 Å. The first light emitting layer 3 is a yellow-green light emitting layer and has a thickness of 160 Å, and the thickness of the light emitting region control layer is 200 Å. The thickness of the light emitting layers or the light emitting region control layer is arbitrarily set for the experiment of the present invention and does not limit the present invention.

The first light emitting layer 2 of the device 2 is a yellow-green light emitting layer and has a thickness of 90 Å. The first light emitting layer 2 is a yellow-green light emitting layer and has a thickness of 90 Å, and the thickness of the light emitting region control layer is 200 Å. The thickness of the light emitting layers or the light emitting region control layer is arbitrarily set for the experiment of the present invention and does not limit the present invention.

The first light emitting layer 3 of the device 3 is a yellow-green light emitting layer and has a thickness of 160 Å. The first light emitting layer 1 is a yellow-green light emitting layer and has a thickness of 20 Å, and the thickness of the emission region control layer is 200 Å. The thickness of the light emitting layers or the light emitting region control layer is arbitrarily set for the experiment of the present invention and does not limit the present invention.

Device 4 is composed of the first light-emitting layer 4, the light-emitting layer, and the light-emitting region control layer. The first light emitting layer 4 is a yellow-green light emitting layer and has a thickness of 180 Å. The thickness of the light emitting region control layer is 200 Å. The thickness of the light emitting layers or the light emitting region control layer is arbitrarily set for the experiment of the present invention and does not limit the present invention.

In Table 1, the elements 5 to 8 are composed of the first light emitting layer, the light emitting region control layer, and the light emitting layer. The light emitting area control layer is expressed as the light emitting area control layer (1) to the light emitting area control layer (4) according to the thickness.

Device 5 is composed of a first light-emitting layer, a light-emitting layer, and a light-emitting region control layer (4). The thickness of the first light emitting layer is 200 Å, the light emitting layer is an optional light emitting layer, a red light emitting layer, and the thickness is 20 Å. The light emitting region control layer 4 is a yellow-green light emitting layer and has a thickness of 180 Å. The thickness of the light emitting layers or the light emitting region control layer is arbitrarily set for the experiment of the present invention and does not limit the present invention.

Devices 6 to 8 are composed of a first light emitting layer, a light emitting region control layer, and a light emitting layer. The light-emitting area control layer is expressed as a light-emitting area control layer (1) to a light-emitting area control layer (3) depending on the thickness.

The thickness of the first light emitting layer of the device 6 is 200 Å, the emission region control layer 1 is a yellow-green light emitting layer, and the thickness is 20 Å. The light emitting layer is an arbitrary light emitting layer, which is a red light emitting layer and has a thickness of 20 Å, and the emission area control layer 3 is a yellow-green light emitting layer and has a thickness of 160 Å. In addition, the thickness of the light emitting layers or the light emitting region control layer is arbitrarily set for the experiment of the present invention and does not limit the present invention.

The thickness of the first light emitting layer of the device 7 is 200 Å, the light emitting region control layer 2 is a yellow-green light emitting layer, and the thickness is 20 Å. The light emitting layer is an arbitrary light emitting layer, a red light emitting layer, and has a thickness of 20 Å, and the light emitting region control layer 2 is a yellow-green light emitting layer and has a thickness of 90 Å. The thickness of the light emitting layers or the light emitting region control layer is arbitrarily set for the experiment of the present invention and does not limit the present invention.

The thickness of the first light emitting layer of the device 8 is 200 Å, the emission region control layer 3 is a yellow-green light emitting layer, and the thickness is 160 Å. The light emitting layer is an arbitrary light emitting layer, which is a red light emitting layer and has a thickness of 20 Å, and the light emitting region control layer 1 is a yellow-green light emitting layer and has a thickness of 20 Å. The thickness of the light emitting layers or the light emitting region control layer is arbitrarily set for the experiment of the present invention and does not limit the present invention.

As shown in FIG. 5A , the emission intensity is shown when the emission region control layer of the present invention is applied. As a result of checking the emission intensity of the red emission layer, it can be seen that the emission intensity of the devices 1 to 6 increases at the peak wavelength of 600 nm to 650 nm of the emission region of the red emission layer.

That is, in the devices 1 to 6, the emission intensity in the emission peak region of the red emission layer is increased by the exciton generated between the emission region control layer 190 and the first emission layer (EML) 124 . will increase On the other hand, since the emission intensity of devices 7 and 8 is lowered at 600 nm to 650 nm, which is the peak wavelength of the light emitting region of the red light emitting layer, excitons are not generated in devices 7 and 8. can know the sound. Accordingly, it can be confirmed that the emission intensity is increased by applying the emission region control layer of the present invention.

As shown in FIG. 5B , the light emitting area of the first light emitting layer (EML) 124 is a portion indicated by "a". It can be seen that the light emitting area of the second light emitting part 120 is increased from the light emitting area "a" to the light emitting area "E" by the light emitting area control layer 190 . This confirms that by evenly distributing the light emitting area in the light emitting part, deterioration in the light emitting part can be reduced and the lifetime of the device can be improved by inducing an increase in lifetime.

According to this experiment, when two light emitting layers are configured in one light emitting part, which is an embodiment of the present invention, the light emitting regions of the two light emitting layers are separated from each other. It can be seen that this is prevented by Accordingly, it can be seen that the emission region is increased by evenly spreading the distribution of the emission region, and the emission intensity is also increased in a desired wavelength region.

Accordingly, since the light emitting area is evenly distributed in the second light emitting part 120 , deterioration in the second light emitting part 120 can be reduced and the lifetime of the device can be improved by inducing an increase in lifespan.

6 is a view showing a white organic light emitting diode according to another embodiment of the present invention. In describing the present embodiment, a description of the same or corresponding components as in the previous embodiment will be omitted.

In another embodiment of the present invention, the white organic light emitting device 300 includes a first electrode 102 and a second electrode 104 , and a first light emitting unit 110 between the first and second electrodes 102 and 104 , and A second light emitting unit 120 is provided. A red light emitting layer is configured as a first light emitting layer (EML) 114 of the first light emitting unit 110 , and yellow-green as a second light emitting layer (EML) 115 of the first light emitting unit 110 . (Yellow-Green) constitutes a light emitting layer. The first light emitting layer (EML) 124 of the second light emitting unit 120 constitutes a blue light emitting layer.

In addition, an emission area control layer (EACL) 290 is formed on the first light emitting unit 110 . The light emitting region control layer 290 includes a yellow-green light emitting layer.

A peak wavelength of the emission region of the red emission layer that is the first emission layer (EML) 114 of the first emission unit 110 may be in a range of 600 nm to 650 nm. In addition, a peak wavelength of the emission region of the yellow-green emission layer, which is the second emission layer (EML) 115 , may be in a range of 510 nm to 580 nm. A peak wavelength of the light emitting region of the blue light emitting layer that is the first light emitting layer (EML) 124 of the second light emitting unit 120 may be in a range of 510 nm to 580 nm.

A peak wavelength of the emission region of the yellow-green emission layer that is the emission region control layer (EACL) 290 may be in a range of 510 nm to 580 nm.

The first light emitting layer (EML) 124 of the second light emitting unit 120 may include a blue light emitting layer or a red-blue light emitting layer. A peak wavelength of the emission region of the blue emission layer may be in a range of 440 nm to 480 nm. A peak wavelength of the emission region of the red-blue emission layer may be in a range of 600 nm to 650 nm.

The second light emitting layer (EML) 115 and the light emitting area control layer (EACL) 290 of the first light emitting unit 110 may have the same dopant and different hosts, It is not necessarily limited to this.

The host may be composed of two hosts in addition to one, a hole host and a charge host. It is preferable that the hole mobility of the host included in the emission area control layer (EACL) 290 is faster than that of the host of the second emission layer (EML) 115 . For example, the hole mobility of the emission area control layer (EACL) 290 is preferably faster than 1×10 −5 cm 2 /Vs. This makes the generation of excitons in the emission area control layer (EACL) 290 faster than excitons generated in the second emission layer (EML) 115, so that the second emission layer (EML) 115 is generated faster. It is possible to move the excitons away from the first light emitting layer (EML) 114 .

The density of excitons generated in the first emission layer (EML) 114 and the second emission layer (EML) 115 is reduced by the emission region control layer (EACL) 290 . Accordingly, the distribution of excitons of the second emission layer (EML) 115 is moved away from the first emission layer (EML) 114 by the emission area control layer (EACL) 190 . Accordingly, the light emitting area of the first light emitting layer (EML) 114 and the second light emitting layer (EML) 115 are separated to improve aggregation of the light emitting area, and deterioration in the first light emitting part 110 is improved. it will slow down

Accordingly, since the light emitting area is evenly distributed in the first light emitting part 110 , deterioration in the first light emitting part 110 can be reduced, and the lifetime of the device can be improved by inducing an increase in lifespan.

The white organic light emitting diode according to another embodiment of the present invention may be applied to a bottom emission method, a top emission method, or a positive emission method.

7 is a diagram illustrating a white organic light emitting diode according to another embodiment of the present invention. In describing the present embodiment, a description of the same or corresponding components as in the previous embodiment will be omitted.

Another embodiment of the present invention, the white organic light emitting device 400 includes a first electrode 102 and a second electrode 104, and a first light emitting unit 110 between the first electrode and the second electrode 102 and 104, A second light emitting unit 120 and a third light emitting unit 130 are provided. The first light emitting layer (EML) 114 of the first light emitting unit 110 constitutes a blue light emitting layer, and the first light emitting layer (EML) 124 of the second light emitting unit 120 is yellow-green. A (Yellow-Green) light emitting layer is formed.

A red light emitting layer is further formed as the second light emitting layer (EML) 125 of the second light emitting unit 120 to configure at least two light emitting layers in the second light emitting unit 120 . In addition, the light emitting area control layer (EACL) 390 is formed in the second light emitting unit 120 . The light emitting region control layer 390 is formed of a yellow-green light emitting layer.

A peak wavelength of the light emitting region of the blue light emitting layer that is the first light emitting layer (EML) 114 of the first light emitting unit 110 may be in a range of 440 nm to 480 nm.

A peak wavelength of the emission region of the yellow-green emission layer that is the first emission layer (EML) 124 of the second emission unit 120 may be in a range of 510 nm to 580 nm.

A peak wavelength of the emission region of the red emission layer that is the second emission layer (EML) 125 of the second emission unit 120 may be in a range of 600 nm to 650 nm.

A peak wavelength of the emission region of the yellow-green emission layer that is the emission region control layer (EACL) 390 may be in a range of 510 nm to 580 nm.

The blue light emitting layer made of a fluorescent material has a theoretical quantum efficiency of about 25% compared to the light emitting layer made of a phosphorescent material. For this reason, there is a problem in that the blue light emitting layer made of a fluorescent material does not provide sufficient luminance compared to other phosphorescent materials. Accordingly, a first light emitting layer (EML) 134 is further configured in the third light emitting unit 130 in order to improve the luminous efficiency of the blue light emitting layer to improve lifespan.

Accordingly, in the white organic light emitting device 400 according to another embodiment of the present invention, the first light emitting layer (EML) 114 of the first light emitting unit 110 constitutes a blue light emitting layer, and the second light emitting unit 110 . The third light emitting unit 130 is additionally configured from the light emitting unit configured as the yellow-green light emitting layer as the first light emitting layer (EML) 124 of ( 120 ). The first light emitting layer 134 constituting the third light emitting part may be composed of a blue light emitting layer.

Even in the structure in which the number of light-emitting units is increased by one as described above, when the light-emitting region control layer of the present invention is applied, there is an effect of maintaining the light-emitting efficiency and improving the lifespan. This will be described later with reference to FIG. 8 and Table 2.

Although at least two light emitting layers are configured in the second light emitting unit 120 as an example, it is also possible to configure at least two or more light emitting layers in the second light emitting unit 120 depending on the configuration or characteristics of the device. In addition, it is also possible to configure at least two light emitting layers in the first light emitting unit 110 according to the configuration or characteristics of the device. In addition, it is also possible to configure at least two or more light emitting layers in the third light emitting unit 130 according to the configuration or characteristics of the device.

The first light emitting layer (EML) 124 of the second light emitting part 120 may be composed of one dopant and one host, and may be composed of two hosts composed of a hole host and an electron host in one dopant. can When two hosts are included in one dopant, the efficiency or lifetime of the emission layer may be improved, but the present invention is not limited thereto.

The emission area control layer (EACL) 390 may include one dopant and one host, and may include two hosts including a hole host and an electron host in one dopant. When two hosts are included in one dopant, the efficiency or lifetime of the emission layer may be improved, but the present invention is not limited thereto.

The first light emitting layer (EML) 124 of the second light emitting unit 120 is a yellow-green light emitting layer and the light emitting area control layer (EACL) 390 is yellow-green. The dopant constituting the light emitting layer is the same and the host is configured differently. The host may be composed of two hosts in addition to one, a hole host and a charge host. It is preferable that hole mobility of the host included in the emission area control layer 390 is faster than that of the host of the first emission layer (EML) 124 . For example, the hole mobility of the emission region control layer 390 is preferably faster than 1×10 −5 cm 2 /Vs. This makes the generation of excitons in the emission region control layer 390 faster than excitons generated in the first emission layer (EML) 124, so that the excitons of the first emission layer (EML) 124 ( Exciton) may be moved away from the second light emitting layer (EML) 125 .

Excitons generated in the first light-emitting layer (EML) 124 and the second light-emitting layer (EML) 125 of the second light-emitting unit 120 by the light-emitting region control layer (EACL) 390 are lowering the density. Accordingly, the distribution of excitons in the first emission layer (EML) 124 is moved away from the second emission layer (EML) 125 by the emission region control layer 390 . Accordingly, the light emitting area of the first light emitting layer (EML) 124 and the second light emitting layer (EML) 125 are separated to improve aggregation of the light emitting area, and deterioration in the second light emitting part 120 is improved. it will slow down

Accordingly, since the light emitting area is evenly distributed in the second light emitting part 120 , deterioration in the second light emitting part 120 can be reduced and the lifetime of the device can be improved by inducing an increase in lifespan.

Since the first light emitting unit 110 and the second light emitting unit 120 are the same or corresponding components as in the previous embodiment, descriptions thereof will be omitted.

The third light emitting part 130 includes a third electron transporting layer (ETL) 136 , a first emitting layer (EML) 134 , and a third hole transporting layer under the second electrode 104 . (HTL; Hole Transporting Layer) 132 may be included. Although not shown in the drawings, an electron injection layer (EIL) may be additionally formed on the third electron transport layer (ETL) 136 . In addition, a hole injection layer (HIL) may be additionally configured.

The third hole transport layer (HTL) 132 is TPD (N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-bi-phenyl-4,4'-diamine) or It may be made of NPB (N,N'-di(naphthalen-1-yl)-N,N'-diphenyl-benzidine), but is not necessarily limited thereto.

The third hole transport layer (HTL) 132 may be formed by applying two or more layers or two or more materials.

The third electron transport layer (ETL) 136 may be made of oxadiazole, triazole, phenanthroline, benzoxazole or benzthiazole, etc. It is not necessarily limited to this.

The third electron transport layer (ETL) 136 may be formed by applying two or more layers or two or more materials.

The first emission layer (EML) 134 may include a blue emission layer or a red-blue emission layer. A peak wavelength of the emission region of the blue emission layer may be in a range of 440 nm to 480 nm. A peak wavelength of the emission region of the red-blue emission layer may be in a range of 600 nm to 650 nm.

A second charge generating layer (CGL) 150 may be further formed between the second light emitting unit 120 and the third light emitting unit 130 . The second charge generation layer 150 adjusts the charge balance between the second and third light emitting units 120 and 130 . The second charge generation layer (CGL) 150 may include an N-type charge generation layer (N-CGL) and a P-type charge generation layer (P-CGL).

The N-type charge generation layer (N-CGL) serves to inject electrons into the second light-emitting unit 120 , and the P-type charge generation layer (P-CGL) serves as the third light-emitting unit 130 . It serves to inject holes. The present invention is not limited thereto, and the second charge generating layer (CGL) 150 may be formed as a single layer.

The N-type charge generation layer (N-CGL) may be formed of an organic layer doped with an alkali metal such as Li, Na, K, or Cs, or an alkaline earth metal such as Mg, Sr, Ba, or Ra, respectively, but it must be It is not limited.

Each of the P-type charge generation layers (P-CGL) may be formed of an organic layer including a P-type dopant, but is not limited thereto. The first charge generation layer (CGL) 140 is made of the same material as the N-type charge generation layer (N-CGL) of the second charge generation layer (CGL) 150 and the P-type charge generation layer (P-CGL) may be made, but is not necessarily limited thereto.

In addition, although the white organic light emitting diode according to another embodiment of the present invention has been described with respect to the bottom emission method, it may be applied to the top emission method or the positive emission method.

8 is a view showing emission intensity of a white organic light emitting diode according to a comparative example and an embodiment of the present invention.

As a comparative example, a red light emitting layer and a yellow-green light emitting layer are configured as light emitting layers in the second light emitting part.

In an embodiment of the present invention, the first light emitting unit, the second light emitting unit and the third light emitting unit are configured, and at least two or more light emitting layers and a light emitting region control layer are configured in the second light emitting unit. The first light emitting layer (EML) 114 of the first light emitting part is formed of a blue light emitting layer. The first and second light emitting layers (EML) 124 and 125 of the second light emitting part are composed of a yellow-green light emitting layer and a red light emitting layer. The light emitting region control layer is composed of a yellow-green light emitting layer. The first light emitting layer (EML) 134 of the third light emitting part is formed of a blue light emitting layer.

In FIG. 8 , the horizontal axis represents the wavelength region of light, and the vertical axis represents light emission intensity.

In Examples A and B, the thicknesses of the first light-emitting layer, the second light-emitting layer, and the light-emitting region control layer were applied differently. In Example A, the sum of the thicknesses of the first light emitting layer and the light emitting region control layer and the thickness of the first light emitting layer of Comparative Example were the same. In Example B, the sum of the thicknesses of the first light emitting layer and the light emitting region control layer and the thickness of the first light emitting layer of Comparative Example were thicker.

As shown in FIG. 8, it can be seen that the emission intensity of Comparative Examples, Examples A and B in the range of 440 nm to 480 nm of the peak wavelength of the emission region of the blue light emitting layer has little change. can It can be seen that this does not affect the lifetime of the light emitting layer, which is generated when two or more light emitting layers are configured in one light emitting unit, and the light emitting intensity is maintained.

It can be seen that the peak wavelength of the light emitting region of the yellow-green light emitting layer has an emission intensity of Example B in the range of 510 nm to 580 nm, compared to the comparative example. It can be seen that since the light emitting efficiency of the blue light emitting layer is not lowered and the light emitting efficiency of the blue light emitting layer is increased, the device lifespan can be improved. And, comparing Example A and Example B, it can be seen that Example B has an increased light emission intensity than Example A. This seems to be because, in Example B, as the thickness of the device increases, excitons in the light emitting layer move to the electron transport layer, so that the excitons less destroy the hole transport layer.

The peak wavelength of the emission region of the red emission layer may be in the range of 600 nm to 650 nm, and the emission intensity of Examples A and B may be increased than that of Comparative Examples. It can be seen that since the luminous efficiency of the red emitting layer is not lowered and the luminous efficiency of the red emitting layer is increased, the device lifespan can be improved. In addition, it is possible to solve the problem of a decrease in the luminous efficiency of the red light emitting layer that occurs during device configuration.

As described above, when the light emitting region control layer of the present invention is applied, it can be seen that device characteristics are maintained and device lifespan is improved.

And, Table 2 below compares the efficiency, quantum efficiency, and lifespan according to a comparative example and an embodiment of the present invention.

Comparative Example and Examples A and B are the same as those described with reference to FIG. 7 . That is, in an embodiment of the present invention, the first light emitting unit, the second light emitting unit, and the third light emitting unit are configured, and at least two or more light emitting layers and a light emitting region control layer are configured in the second light emitting unit. The first light emitting layer (EML) 114 of the first light emitting part is formed of a blue light emitting layer. The first light emitting layer (EML) 124 of the second light emitting part is a yellow-green light emitting layer and the second light emitting layer (EML) 125 is red. It is composed of a light emitting layer. A yellow-green light emitting layer is formed as the light emitting region control layer on the first light emitting layer (EML) 124 . The first light emitting layer (EML) 134 of the third light emitting part is formed of a blue light emitting layer.

As a comparative example, a red light emitting layer and a yellow-green light emitting layer are configured as light emitting layers in the second light emitting part.

As shown in Table 2, it can be seen that there is no change in the efficiency of the light emitting layers in Comparative Example and Examples A and B. It can be seen that when two light emitting layers are configured in one light emitting part of the present invention, there is no effect in terms of efficiency compared to the comparative example. It can be seen that this does not affect device characteristics generated when two or more light emitting layers are configured in one light emitting part, and the light emitting efficiency is maintained.

In addition, it can be seen from the device characteristics that when two or more light emitting layers are configured in one light emitting part, the increase of the driving voltage V does not appear.

EQE (External quantum efficiency) is external quantum efficiency and refers to the luminous efficiency when light exits the organic light emitting device. EQE also, it can be seen that there is no change even when two or more light emitting layers are configured in one light emitting part when compared with the comparative example. That is, it can be seen that there is no influence on the luminous efficiency.

And, it can be seen that the lifespan of the light emitting layers is improved by about 10% to 50% compared to the comparative example. That is, compared to the comparative example, when two or more light emitting layers are configured in one light emitting unit, the lifetime decrease does not occur, and the lifespan of the red light emitting layer, the green light emitting layer, and the blue light emitting layer is improved. . Therefore, it can be seen that the lifespan of the white color is improved by 20% to 40% compared to the comparative example.

In addition, it can be seen that even if one light emitting unit is additionally configured in addition to the two light emitting units, when the light emitting region control layer of the present invention is applied, device characteristics such as luminous efficiency are maintained and device lifespan is improved.

In the present invention, the configuration of the second light emitting unit with at least two light emitting layers has been described as an example, but in addition to the at least two light emitting layers, it is also possible to configure the second light emitting unit with two or more light emitting layers depending on the configuration or characteristics of the device. In addition, it is also possible to configure the first light emitting unit as at least two light emitting layers in addition to the second light emitting unit according to the configuration or characteristics of the device. In addition, it is also possible to configure the third light emitting unit as at least two light emitting layers in addition to the second light emitting unit according to the configuration or characteristics of the device.

9 is a view showing a white organic light emitting diode according to another embodiment of the present invention. In describing the present embodiment, a description of the same or corresponding components as in the previous embodiment will be omitted.

Another embodiment of the present invention, the white organic light emitting device 500 includes a first electrode 102 and a second electrode 104, and a first light emitting unit 110 between the first electrode and the second electrode 102 and 104, A second light emitting unit 120 and a third light emitting unit 130 are provided.

The first light emitting layer (EML) 114 of the first light emitting unit 110 is composed of a red light emitting layer, and the second light emitting layer (EML) 115 is composed of a yellow-green light emitting layer. .

The first light emitting layer (EML) 124 of the second light emitting unit 120 is composed of a blue light emitting layer, and the first light emitting layer (EML) 134 of the third light emitting unit 130 is blue. ) is composed of a light emitting layer.

In addition, the light emitting area control layer (EACL) 490 is formed in the first light emitting unit 110 , and the light emission area control layer (EACL) 490 is formed of a blue light emission layer.

A peak wavelength of the emission region of the red emission layer that is the first emission layer (EML) 114 of the first emission unit 110 may be in a range of 600 nm to 650 nm. A peak wavelength of the emission region of the yellow-green emission layer that is the second emission layer (EML) 115 may be in a range of 510 nm to 580 nm.

A peak wavelength of the light emitting region of the blue light emitting layer that is the first light emitting layer (EML) 124 of the second light emitting unit 120 may be in a range of 440 nm to 480 nm.

A peak wavelength of the light emitting region of the blue light emitting layer that is the first light emitting layer (EML) 134 of the third light emitting unit 130 may be in a range of 440 nm to 480 nm.

A peak wavelength of the emission region of the yellow-green emission layer that is the emission region control layer (EACL) 490 may be in a range of 510 nm to 580 nm.

The first light emitting layer (EML) 124 of the second light emitting unit 110 may be configured as a red-blue light emitting layer according to the configuration or characteristics of the device. A peak wavelength of the emission region of the red-blue emission layer may be in a range of 600 nm to 650 nm.

In addition, the first light emitting layer (EML) 134 of the third light emitting unit 110 may be configured as a red-blue light emitting layer according to the configuration or characteristics of the device. A peak wavelength of the emission region of the red-blue emission layer may be in a range of 600 nm to 650 nm.

The second emission layer (EML) 115 and the emission region control layer (EACL) 490 may have the same dopant and different hosts, but are not limited thereto.

The second light-emitting layer (EML) 115 and the light-emitting region control layer 490 of the first light-emitting unit 110 may have the same dopant and different host configuration, and must be limited thereto. it is not going to be

The host may be composed of two hosts in addition to one, a hole host and a charge host. It is preferable that the hole mobility of the host included in the emission area control layer 490 is faster than that of the host of the second emission layer (EML) 115 . For example, the hole mobility of the emission area control layer (EACL) 490 is preferably faster than 1×10 −5 cm 2 /Vs. This makes the generation of excitons in the emission area control layer (EACL) 490 faster than excitons generated in the second emission layer (EML) 115, so that the second emission layer (EML) 115 is generated faster. It is possible to move the excitons away from the first light emitting layer (EML) 114 .

The density of excitons generated in the first emission layer (EML) 114 and the second emission layer (EML) 115 is reduced by the emission region control layer (EACL) 490 . Accordingly, the distribution of excitons in the second emission layer (EML) 115 is moved away from the first emission layer (EML) 114 by the emission area control layer (EACL) 490 . Accordingly, the light emitting area of the first light emitting layer (EML) 114 and the second light emitting layer (EML) 115 is moved apart to improve aggregation of the light emitting area and deterioration in the first light emitting part 110 . it will slow down

Accordingly, since the light emitting area is evenly distributed in the first light emitting part 110 , deterioration in the first light emitting part 110 can be reduced, and the lifetime of the device can be improved by inducing an increase in lifespan.

The white organic light emitting diode according to another embodiment of the present invention may be applied to a bottom emission method, a top emission method, or a positive emission method.

10 is a view showing a white organic light emitting diode according to another embodiment of the present invention. In describing the present embodiment, a description of the same or corresponding components as in the previous embodiment will be omitted.

In another embodiment of the present invention, the white organic light emitting device 600 includes a first electrode 102 and a second electrode 104 and a first light emitting unit 110 between the first and second electrodes 102 and 104 . , a second light emitting unit 120 and a third light emitting unit 130 are provided.

The first light emitting layer (EML) 114 of the first light emitting unit 110 is formed of a blue light emitting layer, and the first light emitting layer (EML) 124 of the second light emitting unit 120 is blue. ) is composed of a light emitting layer.

The first light emitting layer (EML) 134 of the third light emitting unit 130 is composed of a red light emitting layer, and the second light emitting layer (EML 135) is composed of a yellow-green light emitting layer, The light emitting area control layer (EACL) 590 is formed on the third light emitting part 130 .

The emission area control layer (EACL) 590 is formed of a yellow-green emission layer.

A peak wavelength of the emission region of the blue emission layer that is the first emission layer (EML) 114 of the first emission unit 110 may be in a range of 440 nm to 480 nm.

A peak wavelength of the light emitting region of the blue light emitting layer that is the first light emitting layer (EML) 124 of the second light emitting unit 120 may be in a range of 440 nm to 480 nm.

A peak wavelength of the light emitting region of the red light emitting layer that is the first light emitting layer (EML 134) of the third light emitting unit 130 may be in a range of 600 nm to 650 nm. A peak wavelength of the emission region of the yellow-green emission layer, which is (EML) 135 , may be in a range of 510 nm to 580 nm.

A peak wavelength of the emission region of the yellow-green emission layer that is the emission region control layer (EACL) 590 may be in a range of 510 nm to 580 nm.

The second light emitting layer (EML) 135 and the light emitting area control layer (EACL) 590 of the third light emitting unit 130 may have the same dopant and different hosts, It is not necessarily limited to this.

The host may be composed of two hosts in addition to one, a hole host and a charge host. It is preferable that the hole mobility of the host included in the emission area control layer (EACL) 590 is faster than that of the host of the second emission layer (EML) 135 . For example, the hole mobility of the emission area control layer (EACL) 590 is preferably faster than 1×10 −5 cm 2 /Vs. This makes the generation of excitons in the light emitting region control layer (EACL) 590 faster than excitons generated in the second light emitting layer (EML) 135, so that the second light emitting layer (EML) 135 . It is possible to move an exciton away from the first light emitting layer (EML) 134 .

The density of excitons generated in the first emission layer (EML) 134 and the second emission layer (EML) 135 is reduced by the emission region control layer (EACL) 590 . Accordingly, the distribution of excitons in the second emission layer (EML) 135 is moved away from the first emission layer (EML) 134 by the emission area control layer (EACL) 590 . Accordingly, the light emitting area of the first light emitting layer (EML) 134 and the second light emitting layer (EML) 135 are moved apart to improve aggregation of the light emitting area and deterioration in the third light emitting part 130 . it will slow down

Accordingly, since the light emitting area is evenly distributed in the third light emitting part 130 , deterioration in the third light emitting part 130 can be reduced, and the lifetime of the device can be improved by inducing an increase in lifespan.

The first light emitting layer (EML) 114 of the first light emitting unit 110 may be configured as a red-blue light emitting layer according to the configuration or characteristics of the device. A peak wavelength of the emission region of the red-blue emission layer may be in a range of 600 nm to 650 nm.

In addition, the first light emitting layer (EML) 124 of the second light emitting unit 110 may be configured as a red-blue light emitting layer according to the configuration or characteristics of the device. A peak wavelength of the emission region of the red-blue emission layer may be in a range of 600 nm to 650 nm.

Although the white organic light emitting diode according to another embodiment of the present invention has been described with respect to a bottom emission method, it may be applied to a top emission method or a positive emission method.

As described in the present invention, when two light emitting layers are configured in one light emitting part, the light emitting area between the two light emitting layers is prevented from being agglomerated because the light emitting areas of the two light emitting layers are separated by the light emitting area control layer. it can be seen that Accordingly, it can be seen that the emission region is increased by making the emission region uniformly distributed, and the emission intensity is also increased in a desired wavelength region.

Therefore, since the light emitting area is evenly distributed in the light emitting part, deterioration in the light emitting part can be reduced, and the lifetime of the device can be improved by inducing an increase in the lifespan.

One of the first light emitting unit and the second light emitting unit may include at least two light emitting layers.

The at least two light emitting layers may include a red light emitting layer and a yellow-green light emitting layer.

The light emitting region control layer may be configured in the light emitting part including the at least two light emitting layers.

The light emitting area control layer may be composed of a yellow-green light emitting layer.

The dopant of the emission region control layer and the yellow-green emission layer constituting the first emission portion or the second emission portion may be the same, and the host may be configured differently.

The hole mobility of the host of the light emitting region control layer may be faster than the hole mobility of the host of the yellow-green light emitting layer constituting the first light emitting part or the second light emitting part.

When the light emitting part including the at least two light emitting layers is the second light emitting part, the first light emitting part may include a blue light emitting layer.

One of the first light emitting unit, the second light emitting unit, and the third light emitting unit may include at least two light emitting layers.

The at least two light emitting layers may include a red light emitting layer and a yellow-green light emitting layer.

The light emitting region control layer may be configured in the light emitting part including the at least two light emitting layers.

The light emitting area control layer may be composed of a yellow-green light emitting layer.

The dopant of the light emitting region control layer and the yellow-green light emitting layer constituting the first light emitting part, the second light emitting part, or the third light emitting part may be the same and the host may be configured differently.

The hole mobility of the light emitting region control layer may be faster than the hole mobility of the yellow-green light emitting layer constituting the first light emitting part, the second light emitting part, or the third light emitting part.

When the light emitting part including the at least two light emitting layers is the second light emitting part, one of the first light emitting part and the third light emitting part may include a blue light emitting layer.

Although the embodiments of the present invention have been described in more detail with reference to the accompanying drawings, the present invention is not necessarily limited to these embodiments, and various modifications may be made within the scope without departing from the technical spirit of the present invention. . Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The protection scope of the present invention should be construed by the claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100, 200, 300, 400, 500, 600: white organic light emitting device
101: substrate 102: first electrode
104: second electrode 110: first light emitting part
120: second light emitting unit 130: third light emitting unit
140: first charge generation layer 150: second charge generation layer
112: first hole transport layer 122: second hole transport layer
132: third hole transport layer 116: first electron transport layer
126: second electron transport layer 136: third electron transport layer
114: the first light emitting layer of the first light emitting part
115: the second light emitting layer of the second light emitting part
124: the first light emitting layer of the second light emitting part
125: the second light emitting layer of the second light emitting part
134: the first light emitting layer of the third light emitting part
135: the second light emitting layer of the third light emitting part
190, 290, 390, 490, 590: light emitting region control layer

Claims (26)

a first light emitting unit disposed between the first electrode and the second electrode and including a first light emitting layer having a peak wavelength of 440 nm to 480 nm;
a second light emitting unit disposed on the first light emitting unit and including a second light emitting layer having a peak wavelength of 600 nm to 650 nm, a third light emitting layer having a peak wavelength of 510 nm to 580 nm, and a fourth light emitting layer; and
and a charge generation layer between the first light emitting part and the second light emitting part. The method of claim 1,
The first light emitting layer includes a blue light emitting layer, a white organic light emitting device. The method of claim 1,
The second light emitting layer includes a red light emitting layer, a white organic light emitting device. The method of claim 1,
The third light emitting layer includes a yellow-green light emitting layer, a white organic light emitting device. The method of claim 1,
The fourth light emitting layer includes a yellow-green light emitting layer, a white organic light emitting device. The method of claim 1,
The third light emitting layer includes the same peak wavelength as the fourth light emitting layer, a white organic light emitting device. The method of claim 1,
The dopant of the third light emitting layer and the fourth light emitting layer is the same, and the host is configured differently. The method of claim 1,
The hole mobility of the host of the fourth light emitting layer is faster than the hole mobility of the host of the third light emitting layer, a white organic light emitting device. The method of claim 1,
The second light emitting layer is disposed adjacent to the first light emitting portion than the third light emitting layer, a white organic light emitting device. The method of claim 1,
The first light emitting unit further comprises a first hole transport layer and a first electron transport layer on the first light emitting layer,
The second light emitting unit further comprises a second hole transport layer and a second electron transport layer on the fourth light emitting layer, a white organic light emitting device. The method of claim 1,
The white organic light emitting device further comprising a third light emitting unit disposed on the second light emitting unit and including a fifth light emitting layer having a peak wavelength of 440 nm to 480 nm. 12. The method of claim 11,
The white organic light emitting device further comprising a second charge generation layer between the second light emitting part and the third light emitting part. 12. The method of claim 11,
The fifth light emitting layer includes a blue light emitting layer, a white organic light emitting device. 12. The method of claim 11,
The third light emitting unit further comprises a third hole transport layer and a third electron transport layer on the fifth light emitting layer, a white organic light emitting device. The method of claim 1,
The second light emitting layer is disposed adjacent to the first light emitting portion than the third light emitting layer, a white organic light emitting device. a first light emitting unit disposed between the first electrode and the second electrode and including a first light emitting layer having a peak wavelength of 440 nm to 480 nm;
a second light emitting unit disposed on the first light emitting unit and including a second light emitting layer having a peak wavelength of 600 nm to 650 nm, a third light emitting layer having a peak wavelength of 510 nm to 580 nm, and a fourth light emitting layer; and
and a third light emitting part on the second light emitting part and including a fifth light emitting layer having the same peak wavelength as that of the first light emitting layer. 17. The method of claim 16,
The first light emitting layer and the fifth light emitting layer include a blue light emitting layer, a white organic light emitting device. 17. The method of claim 16,
The second light emitting layer includes a red light emitting layer, a white organic light emitting device. 17. The method of claim 16,
The third light emitting layer includes a yellow-green light emitting layer, a white organic light emitting device. 17. The method of claim 16,
The fourth light emitting layer includes a yellow-green light emitting layer, a white organic light emitting device. 17. The method of claim 16,
The dopant of the third light emitting layer and the fourth light emitting layer is the same, and the host is configured differently. 17. The method of claim 16,
The hole mobility of the host of the fourth light emitting layer is faster than the hole mobility of the host of the third light emitting layer, a white organic light emitting device. 17. The method of claim 16,
The second light emitting layer is disposed adjacent to the first light emitting portion than the third light emitting layer, a white organic light emitting device. 17. The method of claim 16,
The second light emitting layer is disposed adjacent to the first light emitting portion than the third light emitting layer, a white organic light emitting device. 17. The method of claim 16,
a first charge generation layer between the first light emitting part and the second light emitting part; and
The white organic light emitting device further comprising a second charge generation layer between the second light emitting part and the third light emitting part. 17. The method of claim 16,
The first light emitting unit further comprises a first hole transport layer and a first electron transport layer on the first light emitting layer,
The second light emitting unit further comprises a second hole transport layer and a second electron transport layer on the fourth light emitting layer,
The third light emitting unit further comprises a third hole transport layer and a third electron transport layer on the fifth light emitting layer, a white organic light emitting device.

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