KR102595242B1 - White organic light emitting device - Google Patents

Abstract

The present invention provides a white organic light emitting device that can improve device lifespan. The white organic light emitting device according to an embodiment of the present invention is located between a first electrode and a second electrode and has a peak wavelength of 440 nm to 480 nm. a first light-emitting layer comprising a first light-emitting layer, a second light-emitting layer over the first light-emitting section and 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. a second light emitting unit including a 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 organic light-emitting devices, and more specifically, to white organic light-emitting devices that can improve device lifespan.

Recently, as we have entered the information age, the field of displays that visually express electrical information signals has developed rapidly, and in response to this, various flat display devices with excellent performance such as thinness, lightness, and low power consumption have been developed. Device) is being developed.

Specific examples of such flat panel displays include Liquid Crystal Display devices (LCD), Plasma Display Panel devices (PDP), Field Emission Display devices (FED), and organic light emitting display devices. (Organic Light Emitting Device: OLED), etc.

In particular, organic light emitting display devices are self-emitting devices and have the advantages of fast response speed, high luminous efficiency, brightness, 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 injected from two electrodes, respectively, into the organic light-emitting layer to generate excitons due to the combination of electrons and holes. Additionally, it is a device that uses the principle that light is generated when the generated excitons fall from the excited state to the ground state.

A conventional organic light emitting display device includes a blue light emitting layer made of a blue fluorescent material to realize white color. However, a 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. Because of this, the blue light-emitting layer made of a fluorescent material has a problem in that it does not produce sufficient brightness compared to the phosphorescent material.

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

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

One way is to use the light emitting layer as a single layer. This method can produce a white organic light-emitting device 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 by adding red, green, and blue dopants to a host material with 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 corresponding light-emitting layer due to the characteristics of the dopant itself. In addition, when mixing each emitting layer, the focus is on realizing white light, so it exhibits wavelength characteristics with an emitting peak value at a wavelength other than red, green, and blue. do. Therefore, there was a problem in that the color reproduction rate was lowered when a color filter was included. In addition, the lifespan of the dopant material is different, so color shift occurs during continuous use.

As another method, two light-emitting layers of complementary colors can be stacked to create a structure that emits white light. However, in this structure, when white light passes through the color filter, a difference occurs between the peak wavelength area of each light-emitting layer and the transmission area of the color filter. Therefore, the range of colors that can be expressed is narrowed, which may lead to difficulties in realizing the desired color reproduction rate.

For example, when a blue light emitting layer and a yellow light emitting layer are stacked, white light is emitted as peak wavelengths are formed in the blue wavelength region and the yellow wavelength region. When this white light passes through red, green, and blue color filters, the transmittance of the blue wavelength region is lowered compared to the red or green wavelength region, resulting in lower luminous efficiency and color reproduction rate.

In addition, the luminous efficiency of the yellow phosphorescent light-emitting layer is relatively higher than that of the blue fluorescent light-emitting layer, thereby reducing panel efficiency and color gamut due to the difference in efficiency between the phosphorescent light-emitting layer and the fluorescent light-emitting layer. Additionally, 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 emitting layer and a green-red phosphorescent 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, several methods have been proposed to improve the lifespan of the device. However, a structure that increases the number of light-emitting parts constituting the light-emitting layers causes an increase in manufacturing cost due to an increase in processing and an increase in driving voltage as the thickness of the device increases.

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

Accordingly, through various experiments, the inventors of the present invention invented a white organic light-emitting device with a new structure that can improve device lifespan by forming two or more light-emitting layers within one light-emitting part.

The problem to be solved according to an embodiment of the present invention is to construct a white organic light emitting layer that can improve device lifespan by configuring two or more light emitting layers in one light emitting unit and further constructing a light emitting area control layer that can evenly distribute the light emitting area. 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 an emission area control layer, thereby providing a white organic light emitting device capable of improving device lifespan.

A white organic light emitting device according to another embodiment of the present invention includes a first light emitting unit between the first electrode and the second electrode, a second light emitting unit on the first light emitting unit, and a third light emitting unit on the second light emitting unit. It is composed. 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 that can improve device lifespan.

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

By constructing a light emitting area control layer that can evenly distribute the light emitting area of the light emitting unit according to an embodiment of the present invention, there is an effect of improving device lifespan.

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 described above do 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 showing a white organic light-emitting device according to an embodiment of the present invention.
Figure 2 is a diagram showing an energy band diagram of a light emitting unit according to an embodiment of the present invention.
Figure 3 is a diagram showing a white organic light-emitting device according to another embodiment of the present invention.
Figure 4 is a diagram showing an energy band diagram of a light emitting unit according to another embodiment of the present invention.
FIG. 5A is a diagram showing the light emission intensity of the light emitting unit according to another embodiment of the present invention, and FIG. 5B is a diagram showing the light emitting area of the light emitting unit according to another embodiment of the present invention.
Figure 6 is a diagram showing a white organic light emitting device according to another embodiment of the present invention.
Figure 7 is a diagram showing a white organic light-emitting device according to another embodiment of the present invention.
Figure 8 is a diagram showing the emission intensity of white organic light-emitting devices according to comparative examples and examples of the present invention.
Figure 9 is a diagram showing a white organic light-emitting device according to another embodiment of the present invention.
Figure 10 is a diagram showing a white organic light emitting device according to another embodiment of the present invention.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and will be implemented in various different forms. These embodiments only serve to ensure that the disclosure of the present invention is complete and that common knowledge in the technical field to which the present invention pertains is not limited. It is provided to fully inform those who have 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 embodiments of the present invention are illustrative, and the present invention is not limited to the matters shown. Like reference numerals refer to like elements throughout the specification. Additionally, in describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. When 'includes', 'has', 'consists of', etc. mentioned in this specification are used, other parts may be added unless 'only' is used. When a component is expressed in the singular, the plural is included unless specifically stated otherwise.

When interpreting a component, it is interpreted to include the margin of error even if there is no separate explicit description.

In the case of a description of a positional relationship, for example, if the positional relationship of two parts is described as 'on top', 'on the top', 'on the bottom', 'next to', etc., 'immediately' Alternatively, there may be one or more other parts placed between the two parts, unless 'directly' is used.

In the case of a description of a temporal relationship, for example, if a temporal relationship is described as 'after', 'successfully after', 'after', 'before', etc., 'immediately' or 'directly' Unless used, non-consecutive cases may also be included.

Although first, second, etc. are used to describe various components, these components are not limited by these terms. These terms are merely used to distinguish one component from another. Accordingly, 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 combined or combined with each other, partially or entirely, and various technological interconnections and operations are possible, and each embodiment can be implemented independently of each other or together in a related relationship. It may be possible.

Hereinafter, embodiments of the present invention will be examined in detail through the attached drawings and examples.

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

The white organic light emitting device 100 shown 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. It is provided with unit 120.

The first electrode 102 is an anode that supplies holes, and may be formed of a transparent conductive material such as TCO (Transparent Conductive Oxide), such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide), but it must be It is not limited.

The second electrode 104 is a cathode that supplies electrons and is made of metallic materials such as gold (Au), silver (Ag), aluminum (Al), molybdenum (Mo), magnesium (Mg), or one of these. 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 transparent electrode, and the second electrode 104 may be a reflective electrode. Additionally, 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 transport layer (HTL) 112, a first emitting layer (EML) 114, and a first electron transport layer ( It may be accomplished by including ETL (Electron Transporting Layer) (116).

Although not shown in the drawing, a hole injection layer (HIL) may be additionally configured. The hole injection layer (HIL) is formed on the first electrode 102 and serves to facilitate hole injection 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)). It can be done, but it is not necessarily limited to this.

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, thereby generating 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 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 can be constructed 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. The peak wavelength of the light emitting region of the blue light emitting layer may be in the range of 440 nm to 480 nm. The peak wavelength of the emission region of the red-blue emission layer may be in the 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 composed 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, but must be It is not limited.

The P-type charge generation layer (P-CGL) may each be made of an organic layer containing a P-type dopant, but is not necessarily limited thereto. Additionally, the first charge generation layer (CGL) 140 may be formed as a single layer.

The second light emitting part 120 includes a second hole transport layer (HTL) 122, a second emitting layer (EML) 124, and a second electron transport layer (ETL) 126. ) can be achieved including. Although not shown in the drawing, an electron injection layer (EIL) may be additionally formed on the second electron transport layer (ETL) 126. Additionally, 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 necessarily 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 necessarily limited thereto.

The second electron transport layer (ETL) 126 can 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 composed of a yellow-green light emitting layer. 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.

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 must emit light in both green and red regions, so red The luminous efficiency of the (Red) emitting layer is lower than that of the green (Green). Therefore, in order to improve the light emitting efficiency of the red light emitting layer, a red light emitting layer is further formed as a second light emitting layer (EML) 125.

Figure 2 is a diagram showing 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 displayed.

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

In this configuration, the peak wavelength of the emitting region of the red emitting layer is in the range of 600 nm to 650 nm, and the peak wavelength of the emitting region of the yellow-green emitting layer is within the range of 600 nm to 650 nm. It ranges from 510 nm to 580 nm. Since the emission areas of the red and yellow-green emission layers are close to each other, agglomeration of the emission areas of the red and yellow-green emission layers occurs. 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 lifespan is reduced. In addition, a problem arises in which the desired color cannot be realized at the peak wavelength of the desired emission region.

In order to solve the above problems, the inventors of the present invention improved the agglomeration phenomenon of the light-emitting area that occurs in a structure including at least two light-emitting layers in one light-emitting part, maximized the light-emitting area, and distributed the light-emitting area evenly. A structure was invented.

In other words, a structure that can improve device lifespan was invented by configuring at least two light-emitting layers in one light-emitting part and further constructing a light-emitting area control layer that can evenly distribute the light-emitting area.

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

In describing this embodiment, description of components that are the same as or correspond to the previous embodiment will be omitted.

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

The second light emitting unit 120 includes two light emitting layers and an emission area control layer (EACL) 190. The first light emitting layer (EML) 124 of the second 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. . And, a yellow-green light-emitting layer is formed with the light-emitting area control layer (EACL) 190.

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

The peak wavelength of the emission area of the yellow-green emission layer, which is the emission area control layer (EACL) 190, may be in the range of 510 nm to 580 nm.

Additionally, the white organic light emitting device according to another embodiment of the present invention can be applied to a bottom emission method, a top emission method, or a positive emission method.

Figure 4 is a diagram showing 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 unit 120 are shown as one dopant and one host, but one dopant contains a hole. ) It can be composed of two hosts, a host and an electron host. When one dopant is composed of two hosts, the efficiency and lifespan of the light emitting layer can be improved, but it is not necessarily limited to this.

In the drawing, the emission area control layer (EACL) 190 is shown as one dopant and one host, but it can be made of one dopant and two hosts consisting of a hole host and an electron host. there is. When one dopant is composed of two hosts, the efficiency and lifespan of the light emitting layer can be improved, but it is not necessarily limited to this.

The first light emitting layer (EML) 124 and the light emitting area control layer (EACL) 190 of the second light emitting unit 120 will be described by taking the case of one dopant and two hosts as an example. Holes move from the hole host of the first emission layer (EML) 124 to the hole host of the emission area control layer (EACL) 190. Electrons move from the electron host of the first emitting layer (EML) 124 to the electron host of the emitting area control layer (EACL) 190, and the moved holes and electrons become excitons combined to form the light emitting unit. Light is generated within.

A dopant constituting the yellow-green emitting layer that is the first emitting layer (EML) 124 and a dopant constituting the yellow-green emitting layer that is the emitting area control layer (EACL) 190. can be configured in the same way. And the host constituting the yellow-green emitting layer, which is the first emitting layer (EML) 124, is the host constituting the yellow-green emitting layer, which is the emitting area control layer (EACL) 190. can be configured differently. However, it is not necessarily limited to this. The host may be composed of two hosts, 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 in 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 cm2/Vs. This causes the generation of excitons in the emission area control layer (EACL) 190 faster than the excitons generated in the first emission layer (EML) 124, so that the first emission layer (EML) 124 Exciton can be moved 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 area control layer (EACL) 190. It is ordered. As a result, the exciton distribution of the first emitting layer (EML) 124 is moved away from the second emitting layer (EML) 125 by the emitting area control layer (EACL) 190. Accordingly, the light emitting areas 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 areas, and deterioration within the second light emitting layer (EML) 120. It's about slowing down.

Accordingly, 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 can be reduced and the lifespan can be increased, thereby improving the device lifespan.

FIG. 5A is a diagram showing the light emission intensity of the light emitting unit according to another embodiment of the present invention, and FIG. 5B is a diagram 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 light emission 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 confirm whether the light emitting area control layer (EACL) 190 of the present invention contributes to improving the 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 configuring at least two light-emitting layers in one light-emitting part is effective in improving the lifespan without affecting device characteristics.

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

In this experiment, the device must be composed of the first emitting layer (EML) 124, the second emitting layer (EML) 125, and the emitting area control layer (EACL) 190 of the second emitting portion 120. First, as shown in Table 1, an arbitrary light-emitting layer is formed between the first light-emitting layers (EML) 124 except for the second light-emitting layer (EML) 125. 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 energy is high. This is because it is displayed in red. Therefore, in order to check the emission area and emission intensity of the emission area control layer 190, the device is configured as shown in Table 1 above. In addition, the emission area and emission intensity of the red emission layer, which is an arbitrary emission layer, were confirmed.

In Table 1, devices 1 to 3 are composed of a first emission layer, an emission layer, and an emission area control layer. The first light-emitting layer is expressed as a first light-emitting layer (1) to a first light-emitting layer (4) depending on its thickness.

The first light-emitting layer 1 of device 1 is a yellow-green light-emitting layer and has a thickness of 20 Å, and 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 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 purpose of testing the present invention and does not limit the present invention.

The first light-emitting layer 2 of device 2 is a yellow-green light-emitting layer and has a thickness of 90 Å, and 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 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 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 purpose of testing the present invention and does not limit the present invention.

The first light-emitting layer 3 of device 3 is a yellow-green light-emitting layer and has a thickness of 160 Å, and 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 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 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 purpose of testing the present invention and does not limit the present invention.

Device 4 is composed of a first light-emitting layer 4, a light-emitting layer, and a 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, and 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 thickness of the emission area 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 purpose of testing the present invention and does not limit the present invention.

In Table 1, devices 5 to 8 are composed of a first emission layer, an emission area control layer, and an emission layer. The emission area control layer is expressed as a light emission area control layer (1) to a light emission area control layer (4) depending on its thickness.

Device 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, which is an arbitrary light-emitting layer, and has a thickness of 20 Å. The emission area control layer 4 is a yellow-green emission layer and has a thickness of 180Å. The thickness of the light-emitting layers or the light-emitting area control layer is arbitrarily set for the purpose of testing the present invention and does not limit 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 emission area control layer is expressed as a light emission area control layer (1) to a light emission area control layer (3) depending on its thickness.

The thickness of the first light-emitting layer of device 6 is 200 Å, and the light-emitting area 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. Additionally, the thickness of the light-emitting layers or the light-emitting area control layer was arbitrarily set for the purpose of testing the present invention and does not limit the present invention.

The thickness of the first light-emitting layer of device 7 is 200 Å, and the light-emitting area 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 purpose of testing the present invention and does not limit the present invention.

The thickness of the first emission layer of device 8 is 200 Å, and the emission area control layer 3 is a yellow-green emission 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, and 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 purpose of testing the present invention and does not limit the present invention.

As shown in Figure 5a, the light emission intensity is shown 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 was found that the emission intensity of elements 1 to 6 increased at 600 nm to 650 nm, which is the peak wavelength of the emission region of the red emission layer.

That is, elements 1 to 6 have an emission intensity in the emission peak region of the red emission layer due to excitons generated between the emission area control layer 190 and the first emission layer (EML) 124. It increases. On the other hand, the emission intensity of elements 7 and 8 decreases at 600 nm to 650 nm, which is the peak wavelength of the red emission region, so no excitons are generated in elements 7 and 8. You can see the sound. Therefore, it can be confirmed that the emission intensity increased by applying the emission area control layer of the present invention.

As shown in FIG. 5B, the light emitting area of the first light emitting layer (EML) 124 is indicated by “a”. It can be seen that the light emitting area of the second light emitting unit 120 has increased from the light emitting area “a” to the light emitting area “E” due to the light emitting area adjustment layer 190. This confirms that by evenly distributing the light-emitting area within the light-emitting part, the deterioration phenomenon within the light-emitting part can be reduced and the lifespan of the device can be increased, thereby improving the device lifespan.

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 the agglomeration of the light-emitting areas that occurs between the two light-emitting layers is caused by the light-emitting area control layer. It can be seen that this is prevented. As a result, it can be seen that the light-emitting area increases by spreading the distribution of the light-emitting area evenly, and the light-emitting intensity also increases in the desired wavelength range.

Accordingly, 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 can be reduced and the lifespan can be increased, thereby improving the device lifespan.

Figure 6 is a diagram showing a white organic light-emitting device according to another embodiment of the present invention. In describing this embodiment, description of components that are the same as or correspond to the previous embodiment will be omitted.

The white organic light emitting device 300, which is another embodiment of the present invention, includes a first electrode 102 and a second electrode 104, a first light emitting unit 110 between the first electrode and the second electrode 102 and 104, and It is provided with a second light emitting unit 120. 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 forms a yellow-green light emitting layer. (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 in the first light emitting unit 110. The emission area control layer 290 is composed of a yellow-green emission layer.

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

The peak wavelength of the emission area of the yellow-green emission layer, which is the emission 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 unit 120 may be composed of a blue light emitting layer or a red-blue light emitting layer. The peak wavelength of the light emitting region of the blue light emitting layer may be in the range of 440 nm to 480 nm. The peak wavelength of the emission region of the red-blue emission layer may be in the range of 600 nm to 650 nm.

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

The host may be composed of two hosts, 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 in 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 cm2/Vs. This causes the exciton generation of the emission area control layer (EACL) 290 to be faster than the exciton generation in the second emission layer (EML) 115, so that the second emission layer (EML) 115 Exciton can be moved 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 area control layer (EACL) 290. As a result, the exciton distribution 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 areas of the first light-emitting layer (EML) 114 and the second light-emitting layer (EML) 115 are spaced apart to improve the aggregation phenomenon of the light-emitting areas, and deterioration within the first light-emitting layer (EML) 110. It's about slowing down.

Accordingly, since the light-emitting area in the first light-emitting part 110 is evenly distributed, the deterioration phenomenon in the first light-emitting part 110 can be reduced and the lifespan can be increased, thereby improving the device lifespan.

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

Figure 7 is a diagram showing a white organic light-emitting device according to another embodiment of the present invention. In describing this embodiment, description of components that are the same as or correspond to the previous embodiment will be omitted.

A white organic light emitting device 400, which is another embodiment of the present invention, includes a first electrode 102 and a second electrode 104, a first light emitting portion 110 between the first electrodes 102 and the second electrodes 102 and 104, It is provided with a second light emitting unit 120 and a third light emitting unit 130. 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 forms a yellow-green light emitting layer. (Yellow-Green) It consists of a light emitting layer.

A red light-emitting layer is further formed as the second light-emitting layer (EML) 125 of the second light-emitting part 120, thereby forming at least two light-emitting layers within the second light-emitting part 120. In addition, an emission area control layer (EACL) 390 is formed in the second light emitting unit 120. The emission area control layer 390 is composed of a yellow-green emission layer.

The peak wavelength of the light emitting region of the blue light emitting layer, which 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.

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

The peak wavelength of the light emitting region of the red light emitting layer, which is the second light emitting layer (EML) 125 of the second light emitting unit 120, may be in the range of 600 nm to 650 nm.

The peak wavelength of the emission area of the yellow-green emission layer, which is the emission 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. Because of this, the blue light-emitting layer made of a fluorescent material has a problem in that it does not produce sufficient brightness compared to other phosphorescent materials. Accordingly, in order to improve the light emitting efficiency of the blue light emitting layer and thereby improve its lifespan, a first light emitting layer (EML) 134 is further formed in the third light emitting unit 130.

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

Even in a structure in which the number of light emitting units is increased as described above, when the light emitting area control layer of the present invention is applied, the light emitting efficiency is maintained and the lifespan is improved. This will be described later in Figure 8 and Table 2.

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

The first light emitting layer (EML) 124 of the second light emitting unit 120 may be composed of one dopant and one host, or may be composed of one dopant and two hosts composed of a hole host and an electron host. You can. When one dopant is composed of two hosts, the efficiency and lifespan of the light emitting layer can be improved, but it is not necessarily limited to this.

The emission area control layer (EACL) 390 can be composed of one dopant and one host, or can be composed of one dopant and two hosts composed of a hole host and an electron host. When one dopant is composed of two hosts, the efficiency and lifespan of the light emitting layer can be improved, but it is not necessarily limited to this.

The yellow-green light emitting layer is the first light emitting layer (EML) 124 of the second light emitting part 120, and the yellow-green light emitting layer is the light emitting area control layer (EACL) 390. The dopant constituting the light emitting layer is the same, and the host is configured differently. The host may be composed of two hosts, a hole host and a charge host. It is preferable that the hole mobility of the host included in the emission area control layer 390 is faster than that of the host in the first emission layer (EML) 124. For example, the hole mobility of the emission area control layer 390 is preferably faster than 1×10-5 cm2/Vs. This causes the exciton generation of the emission area control layer 390 to be faster than the exciton generation in the first emission layer (EML) 124, and the exciton of the first emission layer (EML) 124 ( Exciton) can be moved away from the second light emitting layer (EML) 125.

Exciton generated in the first emission layer (EML) 124 and the second emission layer (EML) 125 of the second emission part 120 by the emission area control layer (EACL) 390. This lowers the density. As a result, the exciton distribution of the first emitting layer (EML) 124 is moved away from the second emitting layer (EML) 125 by the emitting area control layer 390. Accordingly, the light emitting areas 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 areas, and deterioration within the second light emitting layer (EML) 120. It's about slowing down.

Accordingly, 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 can be reduced and the lifespan can be increased, thereby improving the device lifespan.

Since the description of the first light emitting unit 110 and the second light emitting unit 120 is the same as or corresponds to the previous embodiment, it will be omitted.

The third light emitting unit 130 includes a third electron transport layer (ETL) 136, a first emitting layer (EML) 134, and a third hole transport layer below the second electrode 104. (HTL; Hole Transporting Layer) (132). Although not shown in the drawing, an electron injection layer (EIL) may be additionally formed on the third electron transport layer (ETL) 136. Additionally, 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 composed 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. It is not necessarily limited to this.

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

The first emitting layer (EML) 134 may be composed of a blue emitting layer or a red-blue emitting layer. The peak wavelength of the light emitting region of the blue light emitting layer may be in the range of 440 nm to 480 nm. The peak wavelength of the emission region of the red-blue emission layer may be in the 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. This 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 part 120, and the P-type charge generation layer (P-CGL) serves to inject electrons into the third light emitting part 130. It serves to inject holes. Without being limited thereto, the second charge generation layer (CGL) 150 may be formed as a single layer.

The N-type charge generation layer (N-CGL) may be composed 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, but must be It is not limited.

The P-type charge generation layer (P-CGL) may each be made of an organic layer containing a P-type dopant, but is not necessarily limited thereto. The first charge generation layer (CGL) 140 is made of the same material as the N-type charge generation layer (N-CGL) and the P-type charge generation layer (P-CGL) of the second charge generation layer (CGL) 150. It may consist of, but is not necessarily limited to this.

In addition, the white organic light emitting device according to another embodiment of the present invention has been described in terms of bottom emission, but it can also be applied to top emission or positive emission methods.

Figure 8 is a diagram showing the emission intensity of white organic light-emitting devices according to comparative examples and examples of the present invention.

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

An embodiment of the present invention includes a first light emitting unit, a second light emitting unit, and a third light emitting unit, and the second light emitting unit includes at least two light emitting layers and a light emitting area control layer. 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 unit 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 Figure 8, the horizontal axis represents the wavelength range of light, and the vertical axis represents the intensity of light emission.

Examples A and B apply different thicknesses of the first emitting layer, the second emitting layer, and the emitting area control layer. In Example A, the sum of the thicknesses of the first light-emitting layer and the light-emitting area control layer is equal to the thickness of the first light-emitting layer in the comparative example. Example B is thicker than the sum of the thicknesses of the first light-emitting layer and the light-emitting area control layer and the thickness of the first light-emitting layer in the comparative example.

As shown in Figure 8, it can be seen that there is almost no change in the emission intensity of Comparative Examples, Examples A and Example B in the peak wavelength range of 440 nm to 480 nm in the emission region of the blue emitting layer. You can. It can be seen that this does not affect the lifespan of the light-emitting layer, which occurs when two or more light-emitting layers are formed in one light-emitting part, and the light emission intensity is maintained.

It can be seen that the peak wavelength of the emission area of the yellow-green emission layer is in the range of 510 nm to 580 nm, and that the emission intensity of Example B increases compared to the comparative example. This shows that the device lifespan can be improved because the luminous efficiency of the blue light-emitting layer increases without decreasing the luminous efficiency of the blue light-emitting layer. And, when comparing Example A and Example B, it can be seen that Example B has an increased luminescence intensity compared to Example A. This appears to be because in Example B, as the thickness of the device becomes thicker, the excitons in the light-emitting layer move to the electron transport layer, so the excitons destroy the hole transport layer less.

The peak wavelength of the emission area of the red emission layer is in the range of 600 nm to 650 nm, and the emission intensity of Examples A and Example B can be increased compared to the comparative example. This shows that the device lifespan can be improved because the luminous efficiency of the red light-emitting layer increases without decreasing the luminous efficiency of the red light-emitting layer. In addition, it is possible to solve the problem that the luminous efficiency of the red light-emitting layer decreases during device construction.

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

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

Comparative Example and Examples A and B are the same as those described in FIG. 7 above. That is, an embodiment of the present invention is composed of a first light emitting unit, a second light emitting unit, and a third light emitting unit, and the second light emitting unit is configured with at least two light emitting layers and a light emission area control layer. 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 composed of a yellow-green light emitting layer and the second light emitting layer (EML) 125, a red light emitting layer. The light emitting area control layer is composed of a yellow-green light emitting 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 formed 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. 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 on efficiency compared to the comparative example. It can be seen that this does not affect the device characteristics that occur when two or more light-emitting layers are formed in one light-emitting part, and the light-emitting efficiency is maintained.

And, looking at the device characteristics, it can be seen that the driving voltage (V) does not increase when composed of two or more light-emitting layers in one light-emitting part.

EQE (External quantum efficiency) is external quantum efficiency, which refers to the luminous efficiency when light goes out of the organic light-emitting device. EQE Also, when compared to the comparative example, it can be seen that there is no change even when two or more light-emitting layers are formed within one light-emitting part. In other words, it can be seen that there is no effect on luminous efficiency.

And, compared to the comparative example, it can be seen that the lifespan of the light emitting layers is improved by about 10% to 50%. In other words, compared to the comparative example, the lifespan reduction that occurs when two or more light-emitting layers are used in one light-emitting part did not occur, and the lifespan of the red, green, and blue light-emitting layers was improved. . Therefore, it can be seen that in white, the lifespan is improved by 20% to 40% compared to the comparative example.

In addition, it can be seen that even if one additional light emitting part is configured in addition to the two light emitting parts, when the light emitting area 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 second light emitting unit is made up of at least two light emitting layers as an example, but in addition to the at least two light emitting layers, it is also possible to configure the second light emitting part with two or more light emitting layers depending on the configuration or characteristics of the device. Additionally, depending on the configuration or characteristics of the device, it is 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. Additionally, depending on the configuration or characteristics of the device, in addition to the second light emitting part, it is possible to configure the third light emitting part with at least two or more light emitting layers.

Figure 9 is a diagram showing a white organic light-emitting device according to another embodiment of the present invention. In describing this embodiment, description of components that are the same as or correspond to the previous embodiment will be omitted.

A white organic light emitting device 500, which is another embodiment of the present invention, includes a first electrode 102 and a second electrode 104, a first light emitting portion 110 between the first electrodes 102 and the second electrodes 102 and 104, It is provided with a second light emitting unit 120 and a third light emitting unit 130.

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 blue (blue). ) It consists 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 emitting area control layer (EACL) 490 is made of a blue light emitting layer.

The peak wavelength of the light emitting region of the red light emitting layer, which 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. The peak wavelength of the emission region of the yellow-green emission layer, which is the second emission layer (EML) 115, may be in the range of 510 nm to 580 nm.

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

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

The peak wavelength of the emission area of the yellow-green emission layer, which is the emission area control layer (EACL) 490, may be in the range of 510 nm to 580 nm.

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

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

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

The second light emitting layer (EML) 115 of the first light emitting unit 110 and the light emitting area control layer 490 may have the same dopant and a different host, but are necessarily limited to this. It doesn't work.

The host may be composed of two hosts, 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 in 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 cm2/Vs. This causes the exciton generation of the emission area control layer (EACL) 490 to be faster than the exciton generation in the second emission layer (EML) 115, so that the second emission layer (EML) 115 Exciton can be moved 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 area control layer (EACL) 490. As a result, the exciton distribution of 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 areas of the first light-emitting layer (EML) 114 and the second light-emitting layer (EML) 115 are spaced apart to improve the aggregation phenomenon of the light-emitting areas, and deterioration within the first light-emitting layer (EML) 110. It's about slowing down.

Accordingly, since the light-emitting area in the first light-emitting part 110 is evenly distributed, the deterioration phenomenon in the first light-emitting part 110 can be reduced and the lifespan can be increased, thereby improving the device lifespan.

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

Figure 10 is a diagram showing a white organic light emitting device according to another embodiment of the present invention. In describing this embodiment, description of components that are the same as or correspond to the previous embodiment will be omitted.

The white organic light emitting device 600, which is another embodiment of the present invention, 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. , and is provided with a second light emitting unit 120 and a third light emitting unit 130.

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 blue (blue). ) It consists 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 in the third light emitting unit 130.

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

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

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

The peak wavelength of the emission region of the first emission layer (EML 134) of the third emission unit 130 may be in the range of 600 nm to 650 nm. The second emission layer The peak wavelength of the emission region of the (EML) (135) yellow-green emission layer may be in the range of 510 nm to 580 nm.

The peak wavelength of the emission area of the yellow-green emission layer, which is the emission area control layer (EACL) 590, may be in the 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 a different host, It is not necessarily limited to this.

The host may be composed of two hosts, 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 in 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 cm2/Vs. This causes the exciton generation of the emission area control layer (EACL) 590 to be faster than the exciton generation in the second emission layer (EML) 135, so that the second emission layer (EML) 135 Exciton can be moved 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 area control layer (EACL) 590. As a result, the exciton distribution of the second emitting layer (EML) 135 is moved away from the first emitting layer (EML) 134 by the emitting area control layer (EACL) 590. Accordingly, the light-emitting areas 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 areas, and deterioration within the third light-emitting layer (EML) 130. It's about slowing down.

Accordingly, since the light emitting area is evenly distributed in the third light emitting unit 130, the deterioration phenomenon in the third light emitting unit 130 can be reduced and the lifespan can be increased, thereby improving the device lifespan.

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

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

Although the white organic light emitting device according to another embodiment of the present invention has been described in terms of bottom emission method, it is also possible to apply it to top emission method or positive emission method.

As explained in the present invention, when two light-emitting layers are configured in one light-emitting part, the light-emitting areas of the two light-emitting layers are spaced apart by the light-emitting area control layer, thereby preventing the aggregation of the light-emitting areas that occurs between the two light-emitting layers. You can see that it is. As a result, it can be seen that by distributing the light emitting area evenly, the light emitting area increases, and the light emission intensity also increases in the desired wavelength range.

Therefore, since the light-emitting area is evenly distributed in the light-emitting part, the deterioration phenomenon in the light-emitting part can be reduced and the lifespan can be increased, thereby improving the device 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 be composed of 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 emission area control layer may be composed of a yellow-green emission layer.

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

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

When the light emitting part including at least two light emitting layers is a 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 be composed of 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 emission area control layer may be composed of a yellow-green emission layer.

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

When the light emitting part including at least two light emitting layers is a 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 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 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 idea of the present invention, but are for illustrative purposes, 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 in all respects as illustrative and not restrictive. The scope of protection of the present invention should be interpreted in accordance with the claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of rights 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 the first light emitting part
115: second light-emitting layer of the second light-emitting part
124: first light emitting layer of the second light emitting part
125: second light emitting layer of the second light emitting part
134: first light emitting layer of the third light emitting part
135: second light-emitting layer of the third light-emitting part
190, 290, 390, 490, 590: Emission area adjustment layer

Claims (27)

a first light emitting portion located between the first electrode and the second electrode and including a first light emitting layer;
a second light-emitting unit comprising at least three light-emitting layers: a second light-emitting layer on the first light-emitting part, a third light-emitting layer on the second light-emitting layer and emitting a color different from the second light-emitting layer, and a fourth light-emitting layer; and
A white organic light emitting device comprising a charge generation layer between the first light emitting unit and the second light emitting unit. According to claim 1,
A white organic light emitting device wherein the first light emitting layer includes a blue light emitting layer. According to claim 1,
A white organic light emitting device wherein the second light emitting layer includes a red light emitting layer. According to claim 1,
The third light emitting layer and the fourth light emitting layer include the same peak wavelength. 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. 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,
A white organic light emitting device wherein the dopants of the third and fourth emitting layers are the same, and the hosts are configured differently. According to claim 1,
A white organic light-emitting device wherein 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. According to claim 1,
A white organic light-emitting device, wherein 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 on the first light emitting layer,
The second light emitting unit further includes a second hole transport layer and a second electron transport layer on the fourth light emitting layer. According to claim 1,
A white organic light-emitting device further comprising a third light-emitting part located on the second light-emitting part and including a fifth light-emitting layer that emits the same color as the first light-emitting layer. According to claim 11,
It further includes a second charge generation layer between the second light emitting unit and the third light emitting unit.
A white organic light emitting device. According to claim 11,
A white organic light emitting device wherein the fifth light emitting layer includes a blue light emitting layer. According to claim 11,
The third light emitting unit emits 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. a first light emitting portion located between the first electrode and the second electrode and including a first light emitting layer;
a second light-emitting unit comprising at least three light-emitting layers: a second light-emitting layer on the first light-emitting part, a third light-emitting layer on the second light-emitting layer and emitting a color different from the second light-emitting layer, and a fourth light-emitting layer; and
A white organic light-emitting device, comprising a third light-emitting part located on the second light-emitting part and including a fifth light-emitting layer that emits the same color as the first light-emitting layer. According to claim 16,
The first light emitting layer and the fifth light emitting layer include a blue light emitting layer. According to claim 16,
A white organic light emitting device wherein the second light emitting layer includes a red light emitting layer. According to claim 16,
The third light emitting layer and the fourth light emitting layer include the same peak wavelength. According to claim 16,
The third light emitting layer and the fourth light emitting layer include a peak wavelength of 510 nm to 580 nm. According to claim 16,
The third light emitting layer and the fourth light emitting layer include a yellow-green light emitting layer. According to claim 16,
A white organic light emitting device wherein the dopants of the third and fourth emitting layers are the same, and the hosts are configured differently. According to claim 16,
A white organic light-emitting device wherein 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. According to claim 16,
A white organic light-emitting device, wherein the second light-emitting layer is disposed closer to the first light-emitting part than the third light-emitting layer. According to claim 16,
The fourth light-emitting layer is disposed adjacent to the third light-emitting layer. According to claim 16,
a first charge generation layer between the first light emitting part and the second light emitting part; and
A white organic light emitting device further comprising a second charge generation layer between the second light emitting unit and the third light emitting unit. According to claim 16,
The first light emitting unit includes a first hole transport layer and a first electron transport layer on the first light emitting layer,
The second light emitting unit includes a second hole transport layer and a second electron transport layer on the fourth light emitting layer,
A white organic light emitting device wherein the third light emitting unit includes a third hole transport layer and a third electron transport layer on the fifth light emitting layer.