KR20230016245A - White organic light emitting device - Google Patents

Abstract

Provided in the present invention is a white organic light emitting element which can extend the service life of an element. To this end, the white organic light emitting element according to one embodiment of the present invention is characterized by comprising: a first light emitting unit which is located between a first electrode and a second electrode, and includes a first light emitting layer including the peak wavelength from 440 nm to 480 nm; a second light emitting unit which is located above the first light emitting unit, and includes a second light emitting layer including a peak wavelength from 600 nm to 650 nm, a third light emitting layer including a peak wavelength from 510 nm to 580 nm, and a fourth light emitting layer; and a charge generating layer located 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 device lifetime.

Recently, as we enter the information age, the display field 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, the organic light emitting display device is a self-light emitting device and has advantages of a fast response speed and a large luminous efficiency, luminance, and viewing angle compared to other flat panel display devices.

An organic light emitting display device forms an organic light emitting layer 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 of generating light when the generated excitons fall from an excited state to a ground state.

A conventional organic light emitting display device includes a blue light emitting layer made of a blue luminescent material to implement white light. However, the theoretical quantum efficiency of a light emitting layer made of a fluorescent material is about 25% higher than that of a light emitting layer made of a phosphorescent material. Due to this, there is a problem in that the blue light emitting layer made of a fluorescent material does not provide sufficient luminance compared to a phosphorescent material.

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

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

As one method, there is a method of using a light emitting layer as a single layer. In this method, a white organic light emitting diode can be manufactured by using a single material or doping two or more materials. For example, there is a method of using red and green dopants in a blue host or adding red, green and blue dopants to 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 balance of white color.

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 mixing each light emitting layer, the focus is on realizing white light, so that it exhibits wavelength characteristics with an emitting peak value at a wavelength other than red, green, and blue. do. Therefore, there is a problem in that the color reproducibility is lowered when the color filter is included. In addition, the lifespan of the dopant material is different, and a color shift occurs during continuous use.

Alternatively, a structure that emits white light may be obtained by stacking two light emitting layers having a complementary color relationship. 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. Therefore, it may be difficult to implement a desired color gamut due to a narrow range of colors that can be expressed.

For example, when a blue light emitting layer and a yellow light emitting layer are stacked, white light is emitted while peak wavelengths are formed in a blue wavelength region and a 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 lowered compared to the red or green wavelength region, and thus the luminous efficiency and color reproducibility are lowered.

In addition, the luminous efficiency of the yellow phosphorescent light emitting layer is relatively higher than that of the blue fluorescent light emitting layer, and the efficiency difference between the phosphorescent light emitting layer and the fluorescent light emitting layer reduces panel efficiency and color gamut. 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 that the luminance of blue is relatively lower than that of green-red.

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

Accordingly, the inventors of the present invention have recognized the above-mentioned problems, and conducted several experiments that can improve the lifespan of a device by configuring two or more light emitting layers within 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 novel structure capable of improving device lifetime by configuring two or more light emitting layers in one light emitting unit through various experiments.

The 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 unit and further configure a light emitting area control layer capable of evenly distributing the light emitting area, thereby improving the lifetime of the device. It is to provide a light emitting element.

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

A white organic light emitting device 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 over the first light emitting part, and a third light emitting part over the second light emitting part. It consists of At least one of the first light emitting unit, the second light emitting unit, and the third light emitting unit includes an emission area control layer, thereby providing a white organic light emitting device capable of improving device lifetime.

Other embodiment specifics 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 life of the device.

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

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

Since the content of the invention described in the problem to be solved, the means for solving the problem, and the effect above does not specify the essential features of the claim, the scope of the claim is not limited by the matters described in the content of the invention.

1 is a diagram illustrating a white organic light emitting device according to an exemplary 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 view showing a white organic light emitting device according to another 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.
5A is a diagram showing light emission intensity of a light emitting unit according to another embodiment of the present invention, and FIG. 5B is a diagram showing a light emitting area of a light emitting unit according to another embodiment of the present invention.
6 is a view showing a white organic light emitting device according to another embodiment of the present invention.
7 is a view showing a white organic light emitting device according to another embodiment of the present invention.
8 is a graph showing emission intensity of white organic light emitting diodes according to Comparative Example and an embodiment of the present invention.
9 is a view showing a white organic light emitting device according to another embodiment of the present invention.
10 is a diagram illustrating a white organic light emitting device according to another exemplary embodiment of the present invention.

Advantages and features of the present invention, and methods of achieving them, will become clear with reference to the detailed description of the following embodiments taken 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 the present embodiments make the disclosure of the present invention complete, and common knowledge in the art to which the present invention belongs. It is provided to fully inform the holder of the scope of the invention, and the present invention is only defined by the scope of the claims.

The shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of the present invention are illustrative, so the present invention is not limited to the details shown. Like reference numbers designate like elements throughout the specification. In addition, in describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. When 'includes', 'has', 'consists of', etc. mentioned in this specification is used, other parts may be added unless 'only' is used. In the case where a component is expressed in the singular, the case including the plural is included unless otherwise explicitly stated.

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

In the case of a description of a positional relationship, for example, 'on top of', 'on top of', 'at the bottom of', 'next to', etc. Or, unless 'directly' is used, one or more other parts may be located between the two parts.

In the case of a description of a temporal relationship, for example, 'immediately' or 'directly' when a temporal precedence relationship is described in terms of 'after', 'following', 'next to', 'before', etc. It can also include non-continuous cases unless is used.

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

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

Hereinafter, looking at the embodiments of the present invention in detail through the accompanying drawings and embodiments are as follows.

1 is a diagram illustrating a white organic light emitting device according to an exemplary embodiment of the present invention.

The white organic light emitting device 100 shown in FIG. 1 has a first light emitting unit 110 and a second light emitting unit between the first electrode 102 and the second electrode 104, and the first and second electrodes 102 and 104. A part 120 is provided.

The first electrode 102 is an anode for supplying holes and may be formed of ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), etc., which are transparent conductive materials such as TCO (Transparent Conductive Oxide). It is not limited.

The second electrode 104 is a cathode supplying electrons and is formed of metallic materials 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 part 110 includes a first hole transporting layer (HTL) 112, a first emitting layer (EML) 114, and a first electron transporting layer ( It may include an Electron Transporting Layer (ETL) 116.

Although not shown in the drawing, a hole injecting 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 light emitting layer (EML) 114 . The first electron transport layer (ETL) 116 supplies electrons from the second electrode 104 to the first light emitting 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. It can be made, but is not necessarily limited thereto.

In the first light emitting layer (EML) 114, light is generated by recombination of holes supplied through the hole transport layer (HIL) and electrons supplied through the electron transport layer (ETL) 116.

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 necessarily 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 necessarily 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 is composed of a blue light emitting layer or a red-blue light emitting layer. A peak wavelength of the light emitting region of the blue light emitting layer may be in the range of 440 nm to 480 nm. A peak wavelength of a light emitting region of the red-blue light emitting 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 part 110 and the second light emitting part 120 . The first charge generating layer (CGL) 140 adjusts the charge balance between the first light emitting part 110 and the second light emitting part 120 . The charge generating layer 140 may include an N-type charge generating layer (N-CGL) and a P-type charge generating layer (P-CGL).

The N-type charge generating 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 must be It is not limited.

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

The second light emitting unit 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 made including. Although not shown in the drawing, an electron injection layer (EIL) may be additionally formed on the second electron transport layer (ETL) 126 . In addition, a hole injecting 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 necessarily limited thereto.

The second hole transport layer (HTL) 122 may be configured 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 necessarily 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 part 120 is composed of a yellow-green light emitting layer. A peak wavelength of a light emitting region of the yellow-green light emitting layer may be in a range of 510 nm to 580 nm.

In this structure, since the first light emitting layer (EML) 124 of the second light emitting part 120 is a yellow-green light emitting layer and needs to emit light in both green and red regions, it emits red light. (Red) The luminous efficiency of the light emitting layer is lower than that of green. Therefore, in order to improve the luminous efficiency of the red light emitting layer, the 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 part 120, an energy band diagram is shown.

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

In the case of 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 It ranges from 510 nm to 580 nm. Since the emission regions of the red emission layer and the yellow-green emission layer are close to each other, the emission regions of the red and yellow-green emission layers are agglomerated. As a result, the light emitting area is biased to one side of the red or yellow-green light emitting layers. Accordingly, deterioration within the second light emitting unit 120 is accelerated, and device life is reduced. In addition, a problem arises in that a desired color cannot be implemented 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 light emitting regions that occurs in a structure including at least two or more light emitting layers in one light emitting part, maximize the light emitting area, and evenly distribute the light emitting areas. structure was invented.

That is, by configuring at least two light emitting layers in one light emitting unit and further configuring a light emitting area control layer capable of evenly distributing light emitting areas, a structure capable of improving device life was invented.

3 is a view showing a white organic light emitting device according to another embodiment of the present invention.

In describing the present embodiment, descriptions of elements identical to or corresponding to those of the previous embodiment will be omitted.

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

Two light emitting layers and an emission area control layer (EACL) 190 are formed in the second light emitting part 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. In addition, a yellow-green light emitting layer is constituted by the light emitting area control layer (EACL) 190 .

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

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

In addition, the white organic light emitting device 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 drawing, the first light emitting layer (EML) 124 and the second light emitting layer (EML) 125 of the second light emitting part 120 are shown as one dopant and one host, but one dopant has a hole ) host and an electron host. In the case of configuring two hosts with one dopant, the efficiency or lifetime of the light emitting layer can be improved, but is not necessarily limited thereto.

And, although the light emitting area control layer (EACL) 190 is shown as one dopant and one host in the drawing, it may be composed of two hosts composed of a hole host and an electron host in one dopant. there is. In the case of configuring two hosts with one dopant, the efficiency or lifetime of the light emitting layer can be improved, but is not necessarily limited thereto.

The first light emitting layer (EML) 124 and the light emitting area control layer (EACL) 190 of the second light emitting part 120 will be described by taking the case of two hosts in one dopant as an example. Holes move from the hole host of the first light emitting layer (EML) 124 to the hole host of the light emitting area control layer (EACL) 190 . Electrons move from the electron host of the first light emitting layer (EML) 124 to the electron host of the light emitting area control layer (EACL) 190, and the moved holes and electrons combine to become excitons, thereby forming the light emitting part. light comes from within.

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

As shown in FIG. 4, the density of excitons generated in the first light emitting layer (EML) 124 and the second light emitting layer (EML) 125 is reduced by the light emitting area control layer (EACL) 190. is to do As a result, the exciton distribution of the first light emitting layer (EML) 124 is moved away from the second light emitting layer (EML) 125 by the light emitting area control layer (EACL) 190 . Therefore, the light emitting regions of the first light emitting layer (EML) 124 and the second light emitting layer (EML) 125 are spaced apart to improve the agglomeration phenomenon of the light emitting region, and deterioration within the second light emitting part 120 is to slow down

Therefore, since the light emitting area is evenly distributed in the second light emitting part 120, the deterioration phenomenon in the second light emitting part 120 is reduced, and the lifetime of the device is increased by inducing an increase in life.

5A is a diagram showing light emission intensity of a light emitting unit according to another embodiment of the present invention, and FIG. 5B is a diagram showing a light emitting area of a 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 light emitting intensity of the light emitting part as a result of experiments confirming the light emitting area of the light emitting area control layer in another embodiment of the present invention.

In order to confirm whether the light emitting area control layer (EACL) 190 of the present invention contributes to lifespan improvement, the inventors configured 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 unit, the device characteristics are not affected and the lifespan is improved.

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

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

In Table 1, elements 1 to 3 are composed of a first light emitting layer, a light emitting layer, and a light emitting area 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 element 1 is a yellow-green light emitting layer and has a thickness of 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. 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 area control layer is 200 Å. The thickness of the light emitting layers or the light emitting area control layer is arbitrarily set for the experiment of the present invention and is not limited to the present invention.

The first light emitting layer 2 of element 2 is a yellow-green light emitting layer and has a thickness of 90 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. 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 area control layer is arbitrarily set for the experiment of the present invention and is not limited to the present invention.

The first light emitting layer 3 of element 3 is a yellow-green light emitting layer and has a thickness of 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. 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 light emitting region control layer is 200 Å. The thickness of the light emitting layers or the light emitting area control layer is arbitrarily set for the experiment of the present invention and is not limited to the present invention.

Element 4 is composed of the first light emitting layer 4, the light emitting layer, and the light emitting area control layer. The first light emitting layer 4 is a yellow-green light emitting layer and has a thickness of 180 Å. The light emitting layer is a red light emitting layer that is an arbitrary light emitting layer and has a thickness of 20 Å. The thickness of the emission region control layer was set to 200 Å. The thickness of the light emitting layers or the light emitting area control layer is arbitrarily set for the experiment of the present invention and is not limited to the present invention.

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

Element 5 is composed of a first light emitting layer, a light emitting layer, and a light emitting area control layer 4 . The thickness of the first light emitting layer is 200 Å, and the light emitting layer is a red light emitting layer that is an arbitrary light emitting layer and has a thickness of 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 area control layer is arbitrarily set for the experiment of the present invention and is not limited to the present invention.

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

The thickness of the first light emitting layer of element 6 is 200 Å, and the light emitting region control layer 1 is a yellow-green light emitting layer and has a thickness of 20 Å. The light emitting layer is a red light emitting layer, which is an arbitrary light emitting layer, and has a thickness of 20 Å, and the light emitting 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 area control layer is arbitrarily set for the experiment of the present invention and is not limited to the present invention.

The thickness of the first light emitting layer of element 7 is 200 Å, and the light emitting region control layer 2 is a yellow-green light emitting layer and has a thickness of 20 Å. The light emitting layer is a red light emitting layer, which is an arbitrary light emitting layer, and has a thickness of 20 Å, and the light emitting area 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 area control layer is arbitrarily set for the experiment of the present invention and is not limited to the present invention.

The first light emitting layer of element 8 has a thickness of 200 Å, and the light emitting region control layer 3 is a yellow-green light emitting layer and has a thickness of 160 Å. The light emitting layer is a red light emitting layer, which is an arbitrary light emitting layer, and has a thickness of 20 Å. The light emitting area 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 area control layer is arbitrarily set for the experiment of the present invention and is not limited to the present invention.

As shown in Figure 5a, it shows the light emission intensity when the light emitting area 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 elements 1 to 6 increases at a 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 is increased in the emission peak region of the red emission layer by excitons generated between the emission region control layer 190 and the first emission layer (EML) 124. will increase On the other hand, since elements 7 and 8 have lower emission intensity at the peak wavelength of 600 nm to 650 nm, which is the peak wavelength of the light emitting region of the red light emitting layer, no exciton was generated in elements 7 and 8. sound can be heard Therefore, 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 the lifetime of the device can be improved by reducing deterioration in the light emitting portion and inducing an increase in lifetime by uniformly distributing the light emitting region within the light emitting portion.

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 areas of the two light-emitting layers are spaced apart, so that the agglomeration of the light-emitting areas between the two light-emitting layers occurs in the light-emitting area control layer. It can be seen that it is prevented by As a result, it can be seen that the light emitting area is increased by evenly spreading the distribution of the light emitting area, and the light emitting intensity is also increased in a desired wavelength region.

Therefore, since the light emitting area is evenly distributed in the second light emitting part 120, the deterioration phenomenon in the second light emitting part 120 is reduced, and the lifetime of the device is increased by inducing an increase in life.

6 is a view showing a white organic light emitting device according to another embodiment of the present invention. In describing the present embodiment, descriptions of elements identical to or corresponding to those of the previous embodiment will be omitted.

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

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

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

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

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

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

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

The density of excitons generated in the first light emitting layer (EML) 114 and the second light emitting layer (EML) 115 is reduced by the light emitting area control layer (EACL) 290 . As a result, the exciton distribution of the second light emitting layer (EML) 115 is moved away from the first light emitting layer (EML) 114 by the light emitting area control layer (EACL) 190 . Therefore, the light emitting regions of the first light emitting layer (EML) 114 and the second light emitting layer (EML) 115 are spaced apart to improve the agglomeration phenomenon of the light emitting region, and deterioration in the first light emitting part 110 is to slow down

Therefore, since the light emitting area is evenly distributed in the first light emitting part 110, the deterioration phenomenon in the first light emitting part 110 is reduced, and the lifetime of the device is increased by inducing an increase in life.

The white organic light emitting device 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 view showing a white organic light emitting device according to another embodiment of the present invention. In describing the present embodiment, descriptions of elements identical to or corresponding to those of the previous embodiment will be omitted.

A white organic light emitting device 400, which is another embodiment of the present invention, includes a first light emitting unit 110 between a first electrode 102 and a second electrode 104, and 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 part 110 constitutes a blue light-emitting layer, and the first light-emitting layer (EML) 124 of the second light-emitting part 120 constitutes yellow-green. (Yellow-Green) It constitutes the light emitting layer.

At least two light emitting layers are formed in the second light emitting part 120 by further configuring a red light emitting layer with the second light emitting layer (EML) 125 of the second light emitting part 120 . In addition, an emission area control layer (EACL) 390 is formed on the second light emitting unit 120 . The light emitting area control layer 390 is composed of a yellow-green light emitting layer.

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

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

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

A peak wavelength of the light emitting region of the yellow-green light emitting layer of the light emitting area control layer (EACL) 390 may be in the range of 510 nm to 580 nm.

A blue light emitting layer made of a fluorescent material has a theoretical quantum efficiency of about 25% compared to a light emitting layer made of a phosphorescent material. Due to this, 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, in order to improve the lifespan of the blue light emitting layer by improving the light emitting efficiency, the first light emitting layer (EML) 134 is further formed in the third light emitting part 130.

Therefore, 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 part 110 constitutes a blue light emitting layer, and the second light emitting part The third light emitting unit 130 is additionally configured in the light emitting unit comprising the yellow-green light emitting layer with 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.

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

At least two light-emitting layers are provided in the second light-emitting unit 120 as an example, but it is also possible to include at least two or more light-emitting layers in the second light-emitting unit 120 depending on the structure or characteristics of the device. In addition, it is also possible to configure at least two or more light-emitting layers in the first light-emitting part 110 according to the structure 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 part 130 according to the structure 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 In the case of configuring two hosts with one dopant, the efficiency or lifetime of the light emitting layer can be improved, but is not necessarily limited thereto.

The light emitting area control layer (EACL) 390 may be composed of one dopant and one host, or may be composed of two hosts composed of a hole host and an electron host in one dopant. In the case of configuring two hosts with one dopant, the efficiency or lifetime of the light emitting layer can be improved, but is not necessarily limited thereto.

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

Exciton generated in the first light emitting layer (EML) 124 and the second light emitting layer (EML) 125 of the second light emitting part 120 by the light emitting area control layer (EACL) 390 to lower the density. As a result, the exciton distribution of the first light emitting layer (EML) 124 is moved away from the second light emitting layer (EML) 125 by the light emitting area control layer 390 . Therefore, the light emitting regions of the first light emitting layer (EML) 124 and the second light emitting layer (EML) 125 are spaced apart to improve the agglomeration phenomenon of the light emitting region, and deterioration within the second light emitting part 120 is to slow down

Therefore, since the light emitting area is evenly distributed in the second light emitting part 120, the deterioration phenomenon in the second light emitting part 120 is reduced, and the lifetime of the device is increased by inducing an increase in life.

Since the first light emitting part 110 and the second light emitting part 120 are the same as or corresponding to those of 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 injecting 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 consist of NPB (N,N'-di(naphthalen-1-yl)-N,N'-diphenyl-benzidine) or the like, 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. 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 light emitting layer (EML) 134 may include a blue light emitting layer or a red-blue light emitting layer. A peak wavelength of the light emitting region of the blue light emitting layer may be in the range of 440 nm to 480 nm. A peak wavelength of a light emitting region of the red-blue light emitting 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 part 120 and the third light emitting part 130 . The second charge generating layer 150 adjusts the charge balance between the second and third light emitting parts 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 generating layer (N-CGL) serves to inject electrons into the second light emitting part 120, and the P-type charge generating layer (P-CGL) serves to inject electrons into the third light emitting part 130. It serves to inject holes. The second charge generating layer (CGL) 150 may be formed as a single layer without being limited thereto.

The N-type charge generating 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 must be It is not limited.

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

In addition, the white organic light emitting device according to another embodiment of the present invention has been described for bottom emission, but it is also possible to apply it to top emission or positive emission.

8 is a graph showing emission intensity of white organic light emitting diodes according to 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, a first light emitting unit, a second light emitting unit, and a third light emitting unit are configured, and at least two light emitting layers and a light emitting area control layer are configured in the second light emitting unit. The first light emitting layer (EML) 114 of the first light emitting part is composed 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 area 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 composed of a blue light emitting layer.

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

Embodiments A and B apply different thicknesses of the first light emitting layer, the second light emitting layer, and the light emitting region control layer. In Example A, the sum of the thicknesses of the first light emitting layer and the light emitting region control layer was equal to the thickness of the first light emitting layer of Comparative Example. Example B is thicker than 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.

As shown in FIG. 8, it can be seen that the emission intensities of Comparative Example, Example A and Example B are almost unchanged in the peak wavelength range of 440 nm to 480 nm of the light emitting region of the blue light emitting layer. can It can be seen that this does not affect the lifetime of the light emitting layer, which occurs when two or more light emitting layers are formed 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 is in the range of 510 nm to 580 nm, and the emission intensity of Example B is higher than that of the comparative example. It can be seen that the lifespan of the device can be improved because the luminous efficiency of the blue light emitting layer is not lowered and the luminous efficiency of the blue light emitting layer is increased. In addition, when Example A and Example B are compared, it can be seen that Example B has an increased luminous intensity than Example A. This seems to be because, in Example B, excitons in the light emitting layer move to the electron transport layer as the thickness of the device increases, so that the exciton destroys the hole transport layer less.

It can be said that 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 light emitting intensities of Examples A and B are higher than those of Comparative Example. It can be seen that the lifespan of the device can be improved because the luminous efficiency of the red emitting layer is increased without decreasing the luminous efficiency of the red emitting layer. In addition, it is possible to solve the problem of lowering the luminous efficiency of the red light emitting layer that occurs during device configuration.

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

In addition, Table 2 below compares 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 in FIG. 7 above. That is, in an embodiment of the present invention, a first light emitting unit, a second light emitting unit, and a third light emitting unit are configured, and at least two light emitting layers and a light emitting area control layer are configured in the second light emitting unit. The first light emitting layer (EML) 114 of the first light emitting part is composed 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 area control layer on the first light emitting layer (EML) 124 . The first light emitting layer (EML) 134 of the third light emitting part is composed 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, Example A and Example B. When configuring two light emitting layers in one light emitting part of the present invention, it can be seen that there is no effect in terms of efficiency compared to the comparative example. It can be seen that this does not affect device characteristics that occur when two or more light emitting layers are formed in one light emitting unit, and the light emitting efficiency is maintained.

Also, in terms of device characteristics, it can be seen that there is no increase in the driving voltage (V) that occurs when two or more light emitting layers are included in one light emitting unit.

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

And, it can be seen that the lifetime of the light emitting layers is improved by about 10% to 50% compared to the comparative example. That is, in contrast to the comparative example, the lifespan of the red light emitting layer, the green light emitting layer, and the blue light emitting layer is improved without the decrease in lifespan that occurs when two or more light emitting layers are configured in one light emitting unit. . Therefore, it can be seen that the lifespan of white (White) is improved by 20% to 40% compared to the comparative example.

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

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 part with at least two or more light emitting layers in addition to the second light emitting part according to the structure or characteristics of the device. In addition, it is also possible to configure the third light emitting part with at least two or more light emitting layers in addition to the second light emitting part according to the structure or characteristics of the device.

9 is a view showing a white organic light emitting device according to another embodiment of the present invention. In describing the present embodiment, descriptions of elements identical to or corresponding to those of the previous embodiment will be omitted.

A white organic light emitting device 500, which is another embodiment of the present invention, includes a first light emitting unit 110 between a first electrode 102 and a second electrode 104, and 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 part 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 part 120 is composed of a blue light emitting layer, and the first light emitting layer (EML) 134 of the third light emitting part 130 is a blue light emitting layer. ) composed of a light emitting layer.

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

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

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

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

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

Depending on the structure or characteristics of the device, the first light emitting layer (EML) 124 of the second light emitting part 110 may be configured as a red-blue light emitting layer. The peak wavelength of the light emitting region of the red-blue light emitting layer may be in the range of 600 nm to 650 nm.

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

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

The second light-emitting layer (EML) 115 of the first light-emitting part 110 and the light-emitting area control layer 490 may have the same dopant and different hosts, but are limited to this. it is not going to be

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

The density of excitons generated in the first light emitting layer (EML) 114 and the second light emitting layer (EML) 115 is reduced by the light emitting area control layer (EACL) 490 . As a result, the exciton distribution of the second light emitting layer (EML) 115 is moved away from the first light emitting layer (EML) 114 by the light emitting area control layer (EACL) 490 . Therefore, the light emitting regions of the first light emitting layer (EML) 114 and the second light emitting layer (EML) 115 are spaced apart to improve the agglomeration phenomenon of the light emitting region, and deterioration in the first light emitting part 110 is to slow down

Therefore, since the light emitting area is evenly distributed in the first light emitting part 110, the deterioration phenomenon in the first light emitting part 110 is reduced, and the lifetime of the device is increased by inducing an increase in life.

The white organic light emitting device 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 diagram illustrating a white organic light emitting device according to another exemplary embodiment of the present invention. In describing the present embodiment, descriptions of elements identical to or corresponding to those of the previous embodiment will be omitted.

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

The first light emitting layer (EML) 114 of the first light emitting part 110 is composed of a blue light emitting layer, and the first light emitting layer (EML) 124 of the second light emitting part 120 is a blue light emitting layer. ) 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 light emitting area control layer (EACL) 590 is composed of a yellow-green light emitting layer.

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

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

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

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

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

The host may be composed of two hosts other than one, a hole host and a charge host. It is preferable that the hole mobility of the host included in the light emitting area control layer (EACL) 590 is faster than that of the host of the second light emitting layer (EML) 135 . For example, the hole mobility of the light emitting 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 area control layer (EACL) 590 faster than the excitons generated in the second light emitting layer (EML) 135, so that the second light emitting layer (EML) 135 It is possible to move the excitons of (Exciton) away from the first light emitting layer (EML) 134.

The density of excitons generated in the first light emitting layer (EML) 134 and the second light emitting layer (EML) 135 is reduced by the light emitting area control layer (EACL) 590 . As a result, the exciton distribution of the second light emitting layer (EML) 135 is moved away from the first light emitting layer (EML) 134 by the light emitting area control layer (EACL) 590 . Therefore, the light emitting regions of the first light emitting layer (EML) 134 and the second light emitting layer (EML) 135 are spaced apart to improve the agglomeration phenomenon of the light emitting region, and deterioration within the third light emitting layer 130 is to slow down

Therefore, since the light emitting area is evenly distributed in the third light emitting part 130, the deterioration phenomenon in the third light emitting part 130 is reduced, and the lifetime of the device is increased by inducing an increase in life.

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

In addition, the first light emitting layer (EML) 124 of the second light emitting part 110 may be configured as a red-blue light emitting layer according to the configuration or characteristics of the device. The peak wavelength of the light emitting region of the red-blue light emitting layer may be in the 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 in terms of a bottom emission method, it is also possible to apply it to a top emission method or a positive emission method.

As described in the present invention, when configuring two light emitting layers in one light emitting unit, the light emitting area adjusting layer separates the light emitting areas of the two light emitting layers, thereby preventing the agglomeration of the light emitting areas between the two light emitting layers. it can be known that As a result, it can be seen that the light emitting area is increased by uniformly distributing the light emitting area, and the light emitting intensity is also increased in a desired wavelength region.

Therefore, since the light emitting area is evenly distributed in the light emitting part, it is possible to reduce the deterioration phenomenon in the light emitting part and increase the lifespan of the device, thereby improving the lifespan of the device.

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 area control layer may be formed 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 or the second light emitting part may have the same dopant, and the host may be configured differently.

The hole mobility of the host of the light emitting region control layer may be higher 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 unit including the at least two light emitting layers is a second light emitting unit, the first light emitting unit 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 area control layer may be formed 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.

Dopants 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 have the same dopant and different hosts.

The hole mobility of the light emitting region control layer may be higher than that 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 unit including the at least two light emitting layers is the second light emitting unit, one of the first light emitting unit and the third light emitting unit 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 may be variously modified and implemented without departing from the technical spirit of the present invention. . Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain, and the scope of the technical idea of the present invention is not limited by these embodiments. Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting. The protection scope of the present invention should be construed according to the scope of the claims, and all technical ideas within the equivalent range 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 unit
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: first light emitting layer of first light emitting part
115: second light emitting layer of second light emitting part
124: first light emitting layer of second light emitting part
125: second light emitting layer of second light emitting part
134: first light emitting layer of third light emitting part
135: second light emitting layer of third light emitting part
190, 290, 390, 490, 590: emission area control layer

Claims (27)

a first light-emitting unit that is between the first electrode and the second electrode and includes a first light-emitting layer;
a second light emitting unit including a second light emitting layer on the first light emitting unit, a third light emitting layer and a fourth light emitting layer on the second light emitting layer and emitting light of a color different from that of the second light emitting layer; and
A white organic light emitting device comprising a charge generation layer between the first light emitting part and the second light emitting part. According to claim 1,
The first light emitting layer includes a blue light emitting layer, a white organic light emitting device. According to claim 1,
The second light emitting layer includes a red light emitting layer, a white organic light emitting device. According to claim 1,
The third light emitting layer and the fourth light emitting layer include the same peak wavelength, a white organic light emitting device. According to claim 1,
The third light emitting layer and the fourth light emitting layer include a peak wavelength of 510 nm to 580 nm, a white organic light emitting device. According to claim 1,
The third light-emitting layer and the fourth light-emitting layer include a yellow-green light-emitting layer. According to claim 1,
The third light-emitting layer and the fourth light-emitting layer have the same dopants and different hosts, the white organic light-emitting device. According to 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, the white organic light emitting device. According to claim 1,
The second light emitting layer is disposed closer to the first light emitting part than the third light emitting layer. According to claim 1,
The first light emitting unit further includes a first hole transport layer and a first electron transport layer over the first light emitting layer,
The second light emitting unit further comprises a second hole transport layer and a second electron transport layer over the fourth light emitting layer, the white organic light emitting device. According to claim 1,
The white organic light emitting device further comprises a third light emitting portion disposed above the second light emitting portion and including a fifth light emitting layer emitting light of the same color as the first light emitting layer. According to claim 11,
A second charge generation layer between the second light emitting part and the third light emitting part is further included.
, a white organic light emitting device. According to claim 11,
The fifth light emitting layer includes a blue light emitting layer, a white organic light emitting device. According to claim 11,
The third light emitting unit has third electrons on the third hole transport layer and the fifth light emitting layer.
A white organic light emitting device further comprising a transport layer. According to claim 1,
The fourth light emitting layer is disposed adjacent to the third light emitting layer, the white organic light emitting device. a first light-emitting unit that is between the first electrode and the second electrode and includes a first light-emitting layer;
a second light emitting unit including a second light emitting layer on the first light emitting unit, a third light emitting layer and a fourth light emitting layer on the second light emitting layer and emitting light of a color different from that of the second light emitting layer; and
A white organic light emitting device comprising a third light emitting portion disposed on the second light emitting portion and including a fifth light emitting layer emitting light of the same color as 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 and the fourth light emitting layer include the same peak wavelength, a white organic light emitting device. 17. The method of claim 16,
The third light emitting layer and the fourth light emitting layer include a peak wavelength of 510 nm to 580 nm, a white organic light emitting device. 17. The method of claim 16,
The third light-emitting layer and the fourth light-emitting layer include a yellow-green light-emitting layer. 17. The method of claim 16,
The third light-emitting layer and the fourth light-emitting layer have the same dopants and different hosts, the white organic light-emitting device. 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, the white organic light emitting device. 17. The method of claim 16,
The second light emitting layer is disposed closer to the first light emitting part than the third light emitting layer. 17. The method of claim 16,
The fourth light emitting layer is disposed adjacent to the third light emitting layer, the 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
Further comprising a second charge generation layer between the second light emitting part and the third light emitting part, the white organic light emitting device. 17. The method of claim 16,
The first light emitting unit includes a first hole transport layer and a first electron transport layer over the first light emitting layer,
The second light emitting unit includes a second hole transport layer and a second electron transport layer over the fourth light emitting layer,
The third light emitting unit includes a third hole transport layer and a third electron transport layer over the fifth light emitting layer.

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