KR102339080B1 - Organic light emitting device - Google Patents

Abstract

The organic light emitting diode according to an embodiment of the present invention is positioned between an anode and a cathode, a first light emitting part including a first light emitting layer, a second light emitting part disposed on the first light emitting part, and including a second light emitting layer a light emitting unit, and a third light emitting unit positioned on the second light emitting unit and including a third light emitting layer and a fourth light emitting layer, wherein the third light emitting layer is a red light emitting layer and the fourth light emitting layer is a blue light emitting layer; 3 The light emitting layer includes a host, and the host includes an anthracene derivative.

Description

Organic light emitting device {ORGANIC LIGHT EMITTING DEVICE}

The present invention relates to an organic electroluminescent device, and more particularly, to an organic electroluminescent device capable of improving efficiency and lifespan.

A video display device that implements various information on a screen is a key technology in the information and communication era, and is developing in the direction of thinner, lighter, more portable and high-performance. In recent years, with the development of the information society, as the demand for various types of display devices increases, LCD (Liquid Crystal Display), PDP (Plasma Display Panel), ELD (Electro Luminescent Display), FED (Field Emission Display), OLED ( Organic Light Emitting Diode) and other flat panel display devices are being actively researched.

Among them, the organic light emitting device is a device that emits light while electrons and holes are paired and then disappear when charge is injected into the organic light emitting layer formed between the anode and the cathode. The organic electroluminescent device can be formed on a flexible transparent substrate such as plastic, and can be driven at a lower voltage than a plasma display panel or an inorganic electroluminescent (EL) display and consume relatively little power. It has the advantage of being small and the color is excellent. In particular, the organic light emitting diode that realizes white color is a device used for various purposes, such as not only for lighting, but also for a thin light source, a backlight of a liquid crystal display, or a full-color display employing a color filter.

In the development of white organic light emitting diodes, research and development are in progress according to each method because high efficiency and long lifespan, as well as color purity, color stability according to changes in current and voltage, and easiness of device manufacturing are important. The structure of the white organic light emitting device can be largely divided into a single layer light emitting structure, a multilayer light emitting structure, and the like. Among them, a multilayer light emitting structure in which a fluorescent blue light emitting layer and a phosphorescent yellow light emitting layer are stacked (tandem) is mainly adopted for a white organic light emitting diode having a long lifespan.

Specifically, a phosphorescent light emitting unit structure in which a first light emitting unit using a blue fluorescent element as a light emitting layer and a second light emitting unit structure using a yellow phosphorescent element as a light emitting layer are stacked is used. In such a white organic light emitting device, white light is realized by a mixing effect of blue light emitted from a blue fluorescent device and yellow light emitted from a yellow phosphorescent device. A charge generation layer is provided between the first light emitting unit and the second light emitting unit to double the efficiency of the current generated in the light emitting layer and to facilitate charge distribution.

However, in the device having the above-described multilayer light emitting structure, the driving voltage of the entire device having the multilayer light emitting structure is greater than the sum of the driving voltages of the respective light emitting units, or the efficiency of the device compared to the single layer light emitting device is decreased.

The present invention provides an organic electroluminescent device capable of improving efficiency and lifespan.

In order to achieve the above object, the organic electroluminescent device according to an embodiment of the present invention is positioned between the anode and the cathode, the first light emitting unit including a first light emitting layer, located on the first light emitting unit, a second light emitting part including a second light emitting layer, and a third light emitting part positioned on the second light emitting part and including a third light emitting layer and a fourth light emitting layer, wherein the third light emitting layer is a red light emitting layer and the fourth light emitting layer The light emitting layer is a blue light emitting layer, the third light emitting layer includes a host, and the host includes an anthracene derivative.

The third light-emitting layer and the fourth light-emitting layer are adjacent to each other, and the third light-emitting layer is located closer to the anode than the fourth light-emitting layer.

The anthracene derivative is characterized in that it consists of any one selected from the following Chemical Formulas 1 to 3.

[Formula 1]

[Formula 2]

[Formula 3]

In Formula 1, R ₁ to R ₄ are each independently a substituted or unsubstituted aromatic group having 6 to 40 carbon atoms, and in Formulas 2 and 3, R ₁ to R ₅ are each independently, having 6 to 40 carbon atoms. is a substituted or unsubstituted aromatic group of

The anthracene derivative is characterized in that it is any one selected from the compounds shown below.

In addition, the organic light emitting diode according to an embodiment of the present invention is positioned between the anode and the cathode, the first light emitting part including the first light emitting layer, and located on the first light emitting part, the second light emitting layer and the second light emitting layer a second light-emitting part comprising three light-emitting layers, wherein the second light-emitting layer is a red light-emitting layer, the third light-emitting layer is a blue light-emitting layer, the second light-emitting layer comprises a host, and the host comprises an anthracene derivative. do.

The second light-emitting layer and the third light-emitting layer are adjacent to each other, and the second light-emitting layer is located closer to the anode than the third light-emitting layer.

The anthracene derivative is characterized in that it consists of any one selected from the following Chemical Formulas 1 to 3.

[Formula 1]

[Formula 2]

[Formula 3]

In Formula 1, R ₁ to R ₄ are each independently a substituted or unsubstituted aromatic group having 6 to 40 carbon atoms, and in Formulas 2 and 3, R ₁ to R ₅ are each independently, having 6 to 40 carbon atoms. is a substituted or unsubstituted aromatic group of

The anthracene derivative is characterized in that it is any one selected from the compounds shown below.

The present invention facilitates the transfer of holes from the red light emitting layer to the blue light emitting layer by configuring the anthracene derivative in the red light emitting layer adjacent to the blue light emitting layer included in the light emitting part. In the anthracene derivative, the amines bound to both sides of the anthracene have hole properties, so that hole transport is facilitated. Accordingly, since the red light emitting layer and the blue light emitting layer can emit light at the same time, there is an effect that the efficiency of the red light emitting layer and the blue light emitting layer can be increased.

In addition, in the present invention, by using an anthracene derivative as a host for the red light emitting layer, the light emitting efficiency of the blue light emitting layer can be improved by smoothly transferring holes to the adjacent blue light emitting layer. Accordingly, since the efficiency of the blue light emitting layer is improved, the efficiency of the device and the lifetime of the device can be improved.

1 is a view showing an organic electroluminescent device according to a first embodiment of the present invention.
2 is a view showing an organic electroluminescent device according to a second embodiment of the present invention.
3 is a graph showing the intensity of light according to the wavelength of devices manufactured according to Comparative Examples and Examples of the present invention.
4 is a graph showing current density according to voltage of devices manufactured according to Comparative Examples and Examples of the present invention.
5 is a graph showing efficiency according to luminance of devices manufactured according to Comparative Examples and Examples of the present invention;
6 is a graph showing a decrease in luminance over time of devices manufactured according to Comparative Examples and Examples of the present invention;

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

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

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

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

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

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

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

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing an organic electroluminescent device according to a first embodiment of the present invention.

Referring to FIG. 1 , in the organic light emitting device 100 of the present invention, the light emitting units ST1 and ST2 positioned between the anode 110 and the cathode 220 and the electric charge positioned between the light emitting units ST1 and ST2 A generation layer 160 is included. The anode 110 is an electrode for injecting holes and may be any one of indium tin oxide (ITO), indium zinc oxide (IZO), and zinc oxide (ZnO) having a high work function. In addition, when the anode 110 is a reflective electrode, the anode 110 includes a reflective layer made of any one of aluminum (Al), silver (Ag), or nickel (Ni) under a layer made of any one of ITO, IZO, or ZnO. may include more.

The first light emitting part ST1 constitutes one light emitting device unit, and includes a first hole injection layer 120 , a first hole transport layer 130 , a red light emitting layer 140 , a blue light emitting layer 145 , and a first electron. and a transport layer 150 .

The first hole injection layer 120 may serve to smoothly inject holes from the anode 110 to the red light emitting layer 140 , and may include cupper phthalocyanine (CuPc) and poly(3,4)-ethylenedioxythiophene (PEDOT). , PANI (polyaniline) and NPD (N,N-dinaphthyl-N,N'-diphenyl benzidine) may consist of any one or more selected from the group consisting of, but is not limited thereto. The thickness of the first hole injection layer 120 may be 1 to 150 nm. Here, when the thickness of the first hole injection layer 120 is 1 nm or more, the hole injection characteristics can be improved, and when it is 150 nm or less, the increase in the thickness of the first hole injection layer 120 is prevented to prevent an increase in the driving voltage. can do. The first hole injection layer 120 may not be included in the configuration of the organic light emitting device depending on the structure or characteristics of the device.

The first hole transport layer 130 serves to facilitate hole transport, and NPD (N,N-dinaphthyl-N,N'-diphenyl benzidine), TPD (N,N'-bis-(3-methylphenyl) )-N,N'-bis-(phenyl)-benzidine), s-TAD and MTDATA(4,4',4"-Tris(N-3-methylphenyl-N-phenyl-amino)-triphenylamine) The thickness of the first hole transport layer 130 may be in the range of 1 to 150 nm, but when the thickness of the first hole transport layer 130 is 1 nm or more, hole transport is not limited thereto. Characteristics may be improved, and if it is 150 nm or less, an increase in the thickness of the first hole transport layer 130 may be prevented, thereby preventing an increase in the driving voltage.

The red light emitting layer 140 includes a host and a dopant, and the host serves to transfer energy to the dopant. Some of the holes injected from the anode 110 meet electrons in the red light emitting layer 140 to be excited, and some of the holes injected from the anode 110 are injected into the blue light emitting layer 145 through the red light emitting layer 140 . In addition, when the red light emitting layer 140 and the blue light emitting layer 145 are configured, there is a problem that only the red efficiency is increased and the blue efficiency is low. This is because the host included in the red light emitting layer lacks hole transport properties and thus cannot transfer holes to the blue light emitting layer, so that the luminous efficiency of the blue light emitting layer is lowered. Accordingly, both the red light emitting layer 140 and the blue light emitting layer can contribute to light emission only when holes are easily transferred to the blue light emitting layer 145 . Accordingly, the present inventors introduced an anthracene derivative into the host in order to improve hole transport properties of the red light emitting layer 140 . In the anthracene derivative, the amines bound to both sides of the anthracene have hole characteristics, so that holes are smoothly transferred to the light emitting layer. In the present invention, by using an anthracene derivative that facilitates hole transfer as a host of the red light-emitting layer 140 , the light-emitting efficiency of the blue light-emitting layer 145 can be improved by smoothly transferring holes to the adjacent blue light-emitting layer 145 . have.

Accordingly, the host of the red light emitting layer 140 of the present invention is made of any one selected from the following Chemical Formulas 1 to 3.

[Formula 1]

[Formula 2]

[Formula 3]

In Formula 1, R ₁ to R ₄ are each independently a substituted or unsubstituted aromatic group having 6 to 40 carbon atoms, and in Formulas 2 and 3, R ₁ to R ₅ are each independently, having 6 to 40 carbon atoms. is a substituted or unsubstituted aromatic group of

The anthracene derivative is any one selected from the compounds shown below.

The blue light emitting layer 145 includes one of a blue light emitting layer, a dark blue light emitting layer, or a sky blue light emitting layer. The blue light emitting layer 145 includes a host material including CBP or mCP, and may be formed of a phosphor material including a dopant material including _{(4,6-F 2} ppy) _{2 Irpic. Unlike this, spiro-DPVBi} , spiro-6P, distylbenzene (DSB), distrylarylene (DSA), may be made of a fluorescent material including any one selected from the group consisting of PFO-based polymers and PPV-based polymers, but is not limited thereto.

The first electron transport layer 150 serves to facilitate the transport of electrons, and affects the lifespan and efficiency of the organic light emitting diode. The first electron transport layer 150 may be formed of at least one selected from the group consisting of tris(8-hydroxyquinolino)aluminum (Alq3), PBD, TAZ, spiro-PBD, BAlq, and SAlq, but is not limited thereto. The thickness of the first electron transport layer 150 may be 1 to 150 nm. Here, if the thickness of the first electron transport layer 150 is 1 nm or more, it is possible to prevent deterioration of the electron transport characteristics, and if it is 150 nm or less, the increase in the thickness of the first electron transport layer 150 is prevented to prevent an increase in the driving voltage. can do.

A charge generation layer (CGL) 160 is positioned on the first light emitting part ST1 . The first light emitting part ST1 and the second light emitting part ST2 have a structure connected by the charge generation layer 160 . The charge generation layer 160 may be a PN junction charge generation layer in which an N-type charge generation layer 160N and a P-type charge generation layer 160P are joined. At this time, the PN junction charge generation layer 160 generates charges or separates them into holes and electrons to inject charges into the respective light emitting layers. That is, the N-type charge generation layer 160N supplies electrons to the red light-emitting layer 140 and the blue light-emitting layer 145 adjacent to the anode, and the P-type charge generation layer 160P is the light-emitting layer of the second light-emitting part ST2. By supplying holes to the light emitting layer, it is possible to further increase the luminous efficiency of the organic electroluminescent device having a plurality of light emitting layers, and to lower the driving voltage.

The N-type charge generation layer 160N may be formed of a metal or an organic material doped with an N-type. Here, the metal may be one selected from the group consisting of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, La, Ce, Sm, Eu, Tb, Dy and Yb. In addition, as the N-type dopant and the host material used in the N-type doped organic material, a commonly used material may be used. For example, the N-type dopant may be an alkali metal, an alkali metal compound, an alkaline earth metal, or an alkaline earth metal compound. In detail, the N-type dopant may be one selected from the group consisting of Li, Cs, K, Rb, Mg, Na, Ca, Sr, Eu and Yb. The proportion of the dopant is mixed at 1 to 8% with respect to 100% of the entire host. Here, the work function of the dopant is preferably 2.5 eV or more. The host material may be an organic material having 20 or more and 60 or less carbon atoms having a heterocycle including a nitrogen atom, for example, tris(8-hydroxyquinoline)aluminum, triazine, hydroxyquinoline derivatives, and benzazole It may be one material selected from the group consisting of derivatives and silol derivatives.

Meanwhile, the P-type charge generation layer 160P may be formed of a metal or an organic material doped with P-type. Here, the metal may be made of one or two or more alloys selected from the group consisting of Al, Cu, Fe, Pb, Zn, Au, Pt, W, In, Mo, Ni and Ti. In addition, as the material of the P-type dopant and the host used in the P-type doped organic material, a commonly used material may be used. For example, the P-type dopant may include 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), a derivative of tetracyanoquinodimethane, iodine , FeCl ₃ , FeF ₃ and SbCl _{5 It} may be one material selected from the group consisting of. In addition, the host is N,N'-di(naphthalen-1-yl)-N,N-diphenyl-benzidine (NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl) It may be one material selected from the group consisting of -1,1-biphenyl-4,4'-diamine (TPD) and N,N',N'-tetranaphthyl-benzidine (TNB).

Meanwhile, a second hole injection layer 170 , a second hole transport layer 180 , a yellow light emitting layer 190 , a second electron transport layer 200 and an electron injection layer 210 are included on the charge generation layer 160 . A second light emitting unit ST2 that The second hole injection layer 170 , the second hole transport layer 180 , and the second electron transport layer 200 are the first hole injection layer 120 and the first hole transport layer 130 of the first light emitting part ST1 described above. ) and the configuration of the first electron transport layer 150 may be the same as or different from those of the first electron transport layer 150 .

The yellow light-emitting layer 190 may have a yellow-green light-emitting layer, a red light-emitting layer, or a multilayer structure of a yellow-green light-emitting layer and a green light-emitting layer. Here, the yellow light emitting layer 190 includes a yellow-green light emitting layer or a red light emitting layer or a multilayer structure of a red light emitting layer and a green light emitting layer. In this embodiment, a single-layer structure of a yellow light emitting layer emitting yellow green will be described as an example. The yellow light emitting layer 190 is CBP (4,4'-N,N'-dicarbazolebiphenyl) or Balq (Bis(2-methyl-8-quinlinolato-N1,O8)-(1,1'-Biphenyl-4-olato) aluminum) and may be made of a phosphorescent yellow-green dopant that emits yellow green to at least one host selected from among them.

The electron injection layer 210 serves to facilitate electron transport, and Alq ₃ (tris(8-hydroxyquinolino)aluminum), PBD, TAZ, spiro-PBD, BAlq, or SAlq may be used, but is not limited thereto. . On the other hand, the electron injection layer 210 may be formed of a metal compound, a metal compound, for example LiQ, LiF, NaF, KF, RbF, CsF, FrF, BeF _2, MgF _2, CaF _2, SrF _2, BaF ₂ And RaF _{2 It} may be any one or more selected from the group consisting of, but is not limited thereto. The electron injection layer 210 may have a thickness of 1 to 50 nm. Here, when the thickness of the electron injection layer 210 is 1 nm or more, there is an advantage in that the electron injection characteristic can be prevented from being deteriorated, and when it is 50 nm or less, an increase in the thickness of the electron injection layer 210 is prevented to increase the driving voltage. rise can be prevented. Accordingly, the second hole injection layer 170, the second hole transport layer 180, the yellow light emitting layer 190, the second electron transport layer 200 and the electron injection layer 210 on the charge generation layer 160, including The second light emitting unit ST2 is formed. The electron injection layer 210 may be omitted depending on the configuration of the device.

The cathode 220 is positioned on the second light emitting part ST2. The cathode 220 is an electron injection electrode, and may be formed of magnesium (Mg), calcium (Ca), aluminum (Al), silver (Ag), or an alloy thereof having a low work function. Here, the cathode 220 may be formed to be thin enough to transmit light when the organic light emitting device has a front or double-sided light emitting structure, and reflects light when the organic light emitting device has a rear light emitting structure. It can be formed as thick as possible.

As described above, the present invention facilitates the transfer of holes from the red light emitting layer to the blue light emitting layer by using an anthracene derivative in the red light emitting layer adjacent to the blue light emitting layer included in the light emitting part. In the anthracene derivative, the amines bound to both sides of the anthracene have hole properties, so that hole transport is facilitated. According to the present invention, by using an anthracene derivative as a host of the red light emitting layer, it is possible to improve the luminous efficiency of the blue light emitting layer by smoothly transferring holes to the adjacent blue light emitting layer. Accordingly, the transfer of holes to the light emitting layer is facilitated, so that the efficiency of the blue light emitting layer is improved, and the efficiency and lifespan of the device can be improved.

2 is a view showing an organic electroluminescent device according to a second embodiment of the present invention. Hereinafter, the same reference numerals are assigned to the same components as those of the first embodiment, and descriptions thereof will be omitted.

Referring to FIG. 2 , the organic light emitting device 100 of the present invention includes a plurality of light emitting units ST1 , ST2 , ST3 and a plurality of light emitting units ST1 and ST2 positioned between the anode 110 and the cathode 220 . , ST3) and a first charge generation layer 160 and a second charge generation layer 230 positioned between. In the present embodiment, it has been illustrated and described that three light emitting units are positioned between the anode 110 and the cathode 220 , but the present invention is not limited thereto and four or more light emitting units are provided between the anode 110 and the cathode 220 . may include

In more detail, the first light emitting unit ST1 constitutes one light emitting device unit and includes the first light emitting layer 140 . The first light emitting layer 140 may emit any one of red, green, and blue, and in the present embodiment may be a blue light emitting layer that emits blue. The first light emitting part ST1 further includes a first hole injection layer 120 and a first hole transport layer 130 between the anode 110 and the first light emitting layer 140 . In addition, the first light emitting part ST1 further includes a first electron transport layer 150 on the first light emitting layer 140 . Accordingly, the first light emitting part ST1 including the first hole injection layer 120 , the first hole transport layer 130 , the first light emitting layer 140 , and the first electron transport layer 150 on the anode 110 is formed make up The first hole injection layer 120 and the first hole transport layer 130 may not be included in the configuration of the first light emitting part ST1 depending on the structure or characteristics of the device.

A first charge generation layer 160 is positioned on the first light emitting part ST1. The first charge generation layer 160 is a PN junction charge generation layer in which an N-type charge generation layer 160N and a P-type charge generation layer 160P are joined, and generates charges or separates them into holes and electrons in each of the light emitting layers. inject an electric charge

Meanwhile, the second light emitting part ST2 including the second light emitting layer 190 is positioned on the first charge generating layer 160 . The second light emitting layer 190 may emit one color among red, green, and blue. For example, in the present embodiment, the second light emitting layer 190 may be a yellow light emitting layer that emits yellow. The yellow light-emitting layer may have a yellow-green light-emitting layer, a green light-emitting layer, or a multilayer structure of a yellow-green light-emitting layer and a green light-emitting layer. The second light emitting part ST2 further includes a second hole injection layer 170 and a second hole transport layer 180 between the first charge generating layer 160 and the second light emitting layer 190 , and the second A second electron transport layer 200 is further included on the light emitting layer 190 . Since the second electron transport layer 200 is formed in the same manner as the first electron transport layer 150 , a description thereof will be omitted. Accordingly, the second light emitting unit including the second hole injection layer 170 , the second hole transport layer 180 , the second emission layer 190 , and the second electron transport layer 200 on the first charge generation layer 160 . (ST2) is constructed.

A second charge generation layer 230 is positioned on the second light emitting part ST2. The second charge generation layer 230 is a PN junction charge generation layer in which an N-type charge generation layer 230N and a P-type charge generation layer 230P are joined, and generates charges or separates them into holes and electrons in each light emitting layer. inject an electric charge Here, since the N-type charge generation layer 230N is formed in the same manner as the N-type charge generation layer 160N of the first charge generation layer 160 , a description thereof will be omitted. In addition, the P-type charge generation layer 230P has the same configuration as the P-type charge generation layer 160P of the first charge generation layer 160 described above.

A third light emitting part ST3 including a third light emitting layer 250 and a fourth light emitting layer 255 is positioned on the second charge generation layer 230 . The third light emitting layer 250 may emit one color among red, green, and blue. For example, in the present embodiment, the third light emitting layer 250 may be a red light emitting layer that emits red. In order to improve the hole transport property of the red light emitting layer, an anthracene derivative is included in the host. In the anthracene derivative, the amines bonded to both sides of the anthracene have hole characteristics, so that holes are smoothly transferred to the light emitting layer. In the present invention, by using an anthracene derivative that facilitates hole transfer as a host of the red light emitting layer, the light emitting efficiency of the blue light emitting layer can be improved by smoothing the transfer of holes to the adjacent blue light emitting layer.

The fourth light emitting layer 255 may emit one color among red, green, and blue, for example, a blue light emitting layer that emits blue in the present embodiment. The blue light emitting layer includes one of a blue light emitting layer, a dark blue light emitting layer, or a sky blue light emitting layer. The third light emitting part ST3 further includes a third hole transport layer 240 between the second charge generating layer 230 and the third light emitting layer 250 , and the third electrons on the third light emitting layer 250 . It further includes a transport layer 260 and an electron injection layer 210 . Accordingly, a third hole transport layer 240 , a third emission layer 250 , a fourth emission layer 255 , a third electron transport layer 260 and an electron injection layer 210 are included on the second charge generation layer 230 . to constitute a third light emitting unit ST3. The cathode 220 is provided on the third light emitting part ST3 to configure the organic electroluminescent device according to the second embodiment of the present invention. The electron injection layer 210 may be omitted depending on the configuration of the device.

As described above, the present invention facilitates the transfer of holes from the red light emitting layer to the blue light emitting layer by using an anthracene derivative in the red light emitting layer adjacent to the blue light emitting layer included in the light emitting part. In the anthracene derivative, the amines bound to both sides have hole characteristics, so that holes are smoothly transferred to the light emitting layer. According to the present invention, by using an anthracene derivative as a host of the red light emitting layer, it is possible to improve the luminous efficiency of the blue light emitting layer by smoothly transferring holes to the adjacent blue light emitting layer. Accordingly, the transfer of holes to the light emitting layer is facilitated, so that the efficiency of the blue light emitting layer is improved, and the efficiency and lifespan of the device can be improved.

Hereinafter, an embodiment in which the organic electroluminescent device of the present invention is manufactured is disclosed. The following materials for the light emitting layer and the like do not limit the scope of the present invention.

<Comparative example>

An organic electroluminescent device was manufactured by forming a hole injection layer, a hole transport layer, a red emission layer, a blue emission layer, an electron transport layer, an electron injection layer, and a cathode on the ITO substrate. Here, the red light emitting layer was formed of a rubrene derivative.

<Example>

In the same configuration as in the aforementioned comparative example, the red light emitting layer was formed of the following RH-03 compound.

The materials of the light emitting layer in the above comparative examples and examples do not limit the content of the present invention.

The driving voltage, efficiency, and lifespan of the devices manufactured according to the aforementioned Comparative Examples and Examples were measured and shown in Table 1 below. In addition, the intensity of light according to the wavelength of the device was measured and shown in FIG. 3, the current density according to the voltage of the device was measured and shown in FIG. 4, and the efficiency according to the luminance was measured and shown in FIG. The luminance reduction rate was measured and shown in FIG. 6 . (The lifespan of the comparative example is 100% and the lifespan of the example is expressed as a percentage, and the driving current of the device is 10mA/cm2.)

Driving voltage (V) Efficiency (cd/A) life span(%) comparative example 3.8 8.6 100 Example 3.8 9.1 110

Referring to FIG. 3 , in the example in which the anthracene derivative is used for the red light emitting layer, the intensity of blue light appearing in the 440 nm to 450 nm wavelength band is increased, compared to the comparative example in which the rubrene derivative is used in the red light emitting layer, and the red light appearing in the 600 nm to 650 nm wavelength band is increased. light intensity decreased. That is, it can be seen that the intensity of blue light is increased in the device using the anthracene derivative of the present invention for the red light emitting layer.

In addition, referring to Table 1 and FIG. 4 , the device according to the embodiment of the present invention exhibits a driving voltage equivalent to that of the comparative example. In addition, referring to Table 1 and FIG. 5 , the efficiency of the device according to the embodiment of the present invention was increased by 0.5 cd/A compared to that of the comparative example. In addition, referring to Table 1 and FIG. 6 , it can be seen that the lifespan of the device according to the embodiment of the present invention is increased by 10% compared to that of the comparative example.

As described above, the present invention facilitates the transfer of holes from the red light emitting layer to the blue light emitting layer by using the anthracene derivative in the red light emitting layer adjacent to the blue light emitting layer included in the light emitting part. In the anthracene derivative, the amines bonded to both sides of the anthracene have hole characteristics, so that holes are smoothly transferred to the light emitting layer. Accordingly, since the red light emitting layer and the blue light emitting layer can emit light at the same time, there is an effect that the efficiency of the red light emitting layer and the blue light emitting layer can be increased.

In addition, in the present invention, by using an anthracene derivative as a host for the red light emitting layer, the light emitting efficiency of the blue light emitting layer can be improved by smoothly transferring holes to the adjacent blue light emitting layer. Accordingly, since the efficiency of the blue light emitting layer is improved, the efficiency and lifespan of the device can be improved.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical configuration of the present invention can be changed to other specific forms by those skilled in the art to which the present invention pertains without changing the technical spirit or essential features of the present invention. It will be appreciated that this may be practiced. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. In addition, the scope of the present invention is indicated by the following claims rather than the above detailed description. In addition, all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention.

100: organic light emitting device 110: anode
120: first hole injection layer 130: first hole transport layer
140: red light emitting layer 145: blue light emitting layer
150: first electron transport layer 160: charge generation layer
160N: N-type charge generation layer 160P: P-type charge generation layer
170: second hole injection layer 180: second hole transport layer
190: yellow light emitting layer 200: second electron transport layer
210: electron injection layer 220: cathode

Claims (12)

a first light emitting unit positioned between the anode and the cathode and including a first light emitting layer;
a second light emitting unit positioned on the first light emitting unit and including a second light emitting layer; and
a third light emitting unit positioned on the second light emitting unit and including a third light emitting layer and a fourth light emitting layer; and
The third light-emitting layer is a red light-emitting layer and the fourth light-emitting layer is a blue light-emitting layer,
The third light emitting layer includes a host, the host includes an anthracene derivative, and the anthracene derivative has a structure of Formula 3 below.
[Formula 3]

In Formula 3, R ₁ to R ₆ are each independently a substituted or unsubstituted aromatic group having 6 to 40 carbon atoms.
According to claim 1,
The third emission layer and the fourth emission layer are adjacent to each other, and the third emission layer is located closer to the anode than the fourth emission layer.
delete According to claim 1,
The anthracene derivative is an organic electroluminescent device, characterized in that any one selected from the compounds shown below.

a first light emitting unit positioned between the anode and the cathode and including a first light emitting layer; and
a second light emitting unit positioned on the first light emitting unit and including a second light emitting layer and a third light emitting layer; and
The second light-emitting layer is a red light-emitting layer and the third light-emitting layer is a blue light-emitting layer,
The second emission layer includes a host, the host includes an anthracene derivative, and the anthracene derivative has a structure of Formula 3 below.
[Formula 3]

In Formula 3, R ₁ to R ₆ are each independently a substituted or unsubstituted aromatic group having 6 to 40 carbon atoms.
6. The method of claim 5,
The second emission layer and the third emission layer are adjacent to each other, and the second emission layer is located closer to the anode than the third emission layer.
delete 6. The method of claim 5,
The anthracene derivative is an organic electroluminescent device, characterized in that any one selected from the compounds shown below.

a first light emitting unit positioned between the anode and the cathode and including a first light emitting layer and a second light emitting layer;
a second light emitting unit positioned on the first light emitting unit and including a third light emitting layer;
The first light-emitting layer is a red light-emitting layer, the second light-emitting layer is a blue light-emitting layer,
The first light emitting layer is an organic electroluminescent device including a host that is an anthracene derivative having a structure of the following formula (3).
[Formula 3]

In Formula 3, R ₁ to R ₆ are each independently a substituted or unsubstituted aromatic group having 6 to 40 carbon atoms.
The method of claim 1,
The first light emitting layer is a blue light emitting layer, and the second light emitting layer is a yellow green light emitting layer, a green light emitting layer, and one of a yellow green light emitting layer and a green light emitting layer.
6. The method of claim 5,
An organic light emitting diode positioned on the second light emitting part and further comprising a third light emitting part including a fourth light emitting layer, wherein the first light emitting layer and the fourth light emitting layer are blue light emitting material layers.
10. The method of claim 9,
It is positioned on the second light emitting unit and further includes a third light emitting unit including a fourth light emitting layer, wherein the third light emitting layer is one of a yellow green light emitting layer, a green light emitting layer, and a yellow green light emitting layer and a green light emitting layer, The light emitting layer is an organic electroluminescent device that is a blue light emitting layer.

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