KR20160017241A - Heterocyclic compounds and organic light emitting diode device comprising the same - Google Patents

Abstract

A heterocyclic compound according to an embodiment of the present invention can be represented by chemical formula 1. In chemical formula 1, R1 to R6 respectively and independently refer to hydrogen, deuterium, halogen, cyano group, trifluoromethyl group, nitro group, alkyl group with 1 to 6 carbons, alkoxy group with 1 to 6 carbons, cycloalkyl group with 3 to 6 carbons, aryl group with 6 to 30 carbons, and heteroaryl group with 5 to 30 carbons, wherein some of R1 to R6 are neighboring, the neighboring elements can be bonded to form a ring; A refers to CH or N; X1 and X2 respectively and independently refer to one selected from compounds represented by compound 1, wherein Ar refers to either an aryl group with 6 to 30 carbons or a heteroaryl group with 5 to 30 carbons. According to the present invention, the heterocyclic compound has superior thermal stability and thus the electric charge transport efficiency of the organic electroluminescent device including the same can be improved.

Description

TECHNICAL FIELD [0001] The present invention relates to a heterocyclic compound and an organic electroluminescent device including the heterocyclic compound and an organic electroluminescent device including the same.

The present invention relates to a heterocyclic compound and an organic electroluminescent device including the same, and more particularly, to a heterocyclic compound capable of lowering the driving voltage of an organic electroluminescent device and an organic electroluminescent device including the same.

The image display device that realizes various information on the screen is a core technology of the information communication age and it is becoming thinner, lighter, more portable and higher performance. (LCD), a plasma display panel (PDP), an electro luminescent display (ELD), a field emission display (FED), and an organic light emitting diode (OLED) display device, Organic Light Emitting Diode) have been actively studied.

Among these organic electroluminescent devices, electrons and holes are paired when an electric charge is injected into the organic light emitting layer formed between the anode and the cathode, and then the light is emitted while disappearing. The organic electroluminescent device can be formed not only on a flexible transparent substrate such as a plastic but also can be driven at a lower voltage than a plasma display panel (plasma display panel) or an inorganic electroluminescence (EL) display, It has the advantage of being excellent in color. In particular, an organic electroluminescent device that implements white light is used for various purposes such as a thin light source, a backlight of a liquid crystal display device, or a full color display device employing a color filter.

A tandem organic electroluminescent device has a structure in which a plurality of light emitting portions of a hole injecting layer / a hole transporting layer / a light emitting layer / an electron transporting layer / an electron injecting layer are formed between an anode and a cathode, There is a charge generation layer that helps to move. Particularly, the charge generation layer is composed of a P-type and an N-type charge generation layer, and the P-type charge generation layer is involved in charge generation, injection and migration, and the N-type charge generation layer is involved in injection and migration of generated electrons do. Among them, the P-type charge generation layer is composed of a layer made of a single material or a structure composed of a P-type dopant in a matrix.

The P-type charge generation layer having a strong electron-withdrawing substituent receives electrons from the HOMO of the matrix or the adjacent hole injection layer or hole transport layer to the LUMO of the P-type charge generation layer to form a hole transport path. As a result, a P-type charge generation layer material having a strong electron withdrawing substituent is required because efficient charge generation is possible only when the LUMO of the P-type charge generation layer and the HOMO of the matrix have a similar energy value. Typical P-type charge generating layer materials include quinone derivatives, oxocarbon derivatives, radialene derivatives, heterocyclic derivatives, and lewis acids having electron withdrawing substituents.

However, most of the P-type charge generation layer materials known so far are unstable electrochemically or have insufficient sublimation stability in the fabrication process of the organic electroluminescent device, so that it is difficult to apply them to mass production. Particularly, in the case of F4-TCNQ, sublimation occurs at a relatively low temperature due to a low molecular weight of the material, which makes it difficult to deposit the material stably and causes contamination of the vacuum deposition equipment and the substrate of the device during the fabrication of the organic electroluminescent device. There is a problem.

The present invention relates to a heterocyclic compound capable of improving the charge transport efficiency and lowering the driving voltage of an organic electroluminescent device by proposing a heterocyclic compound having a novel structure having an excellent thermal stability and charge transporting property and an organic electroluminescent device Lt; / RTI >

In order to accomplish the above object, a heterocyclic compound according to an embodiment of the present invention is represented by the following general formula (1).

[Chemical Formula 1]

R 1 to R 6 are each independently selected from the group consisting of hydrogen, deuterium, halogen, cyano, trifluoromethyl, nitro, alkyl having 1 to 6 carbon atoms, alkoxy having 1 to 6 carbon atoms, An aryl group having 6 to 30 carbon atoms, and a heteroaryl group having 5 to 30 carbon atoms, which may be connected to each other to form a ring, and A is CH Or N, and X1 and X2 are each independently selected from among the compounds shown below, wherein Ar is an aryl group having 6 to 30 carbon atoms or a heteroaryl group having 5 to 30 carbon atoms.

The heterocyclic compound is characterized by being represented by the following general formula (2) or (3).

(2)

(3)

In addition, the organic electroluminescent device according to an embodiment of the present invention includes at least one organic layer between the anode and the light emitting layer, and between the anode and the light emitting layer, wherein the organic layer includes the heterocyclic compound do.

Wherein the organic layer is at least one selected from the group consisting of a hole injection layer, a hole transport layer and a hole buffer layer.

And the hole injection layer is composed of the heterocyclic compound only.

The hole buffer layer is disposed between the hole injection layer and the hole transport layer and is in contact with the anode.

And the hole buffer layer is positioned between the hole injection layer and the hole transport layer.

The hole buffer layer may be composed of the heterocyclic compound alone or may be composed of a matrix material and the heterocyclic compound.

And the matrix material is the hole transport layer material.

The hole transport layer is located on the hole injection layer, and is formed of the hole transport layer material and the heterocyclic compound.

In addition, the organic electroluminescent device according to an embodiment of the present invention includes the first light emitting portion including a first light emitting layer between an anode and a cathode, the second light emitting portion including a second light emitting layer on the first light emitting portion, And a charge generation layer positioned between the first light emitting portion and the second light emitting portion, wherein the charge generation layer includes an N-type charge generation layer and a P-type charge generation layer, wherein the P-type charge generation layer Is characterized by including the above-mentioned heterocyclic compound.

The first light emitting portion includes at least one organic layer positioned between the anode and the first light emitting layer, wherein the organic layer is at least one of a hole injection layer, a first hole transport layer, and a hole buffer layer.

The first light emitting portion may include a first hole transporting layer, and the P-type charge generating layer may be formed of the heterocyclic compound alone or may be formed of a matrix material and the heterocyclic compound.

And the matrix material is the hole transport layer material.

And the second light emitting portion includes a second hole transporting layer positioned between the P-type charge generating layer and the second light emitting layer.

And the P-type charge generation layer is in contact with the second light emitting layer.

And a third light emitting unit including a third light emitting layer on the second light emitting unit.

The first light emitting portion and the third light emitting portion are blue light emitting layers, and the second light emitting portion is a yellow or yellow light emitting layer.

The present invention has an advantage of improving the charge transport efficiency of an organic electroluminescent device and lowering a driving voltage by including a heterocyclic compound having a novel structure having excellent thermal stability and charge transporting properties.

1 to 3 are views showing an organic electroluminescent device according to a first embodiment of the present invention.
4 to 6 are views showing an organic electroluminescent device according to a second embodiment of the present invention.
7 and 8 are views illustrating an organic electroluminescent device according to a third embodiment of the present invention.
9 is a graph showing the results of differential scanning calorimetry of the compound B of the present invention.
10 is a graph showing the result of thermogravimetric analysis of the compound B of the present invention.
11 is a graph showing the relationship between voltage and current density of an organic electroluminescent device fabricated according to Examples 1 and 2 and Comparative Example of the present invention.
12 is a graph showing the relationship between current efficiency and luminance efficiency of an organic electroluminescent device fabricated according to Examples 1 and 2 and Comparative Example of the present invention.
13 is a graph showing the relationship between current density and luminance of an organic electroluminescent device fabricated according to Examples 1 and 2 and Comparative Example of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

The shapes, sizes, ratios, angles, numbers, and the like disclosed in the drawings for describing the embodiments of the present invention are illustrative, and thus the present invention is not limited thereto. Like reference numerals refer to like elements throughout the specification. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. In the case where the word 'includes', 'having', 'done', etc. are used in this specification, other parts can be added unless '~ only' is used. Unless the context clearly dictates otherwise, including the plural unless the context clearly dictates otherwise.

In interpreting the constituent elements, it is construed to include the error range even if there is no separate description.

In the case of a description of the positional relationship, for example, if the positional relationship between two parts is described as 'on', 'on top', 'under', and 'next to' Or " direct " is not used, one or more other portions may be located between the two portions.

In the case of a description of a temporal relationship, for example, if the temporal relationship is described by 'after', 'after', 'after', 'before', etc., May not be continuous unless they are not used.

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

It is to be understood that each of the features of the various embodiments of the present invention may be combined or combined with each other, partially or wholly, technically various interlocking and driving, and that the embodiments may be practiced independently of each other, It is possible.

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

1 to 3 are views showing an organic electroluminescent device according to a first embodiment of the present invention.

1, an organic electroluminescent device 100 according to a first embodiment of the present invention includes an anode 110, a hole injecting layer 120, a hole transporting layer 130, a light emitting layer 140, an electron transporting layer 150 ), An electron injection layer 160, and a cathode 170.

The anode 110 may be any one of indium tin oxide (ITO), indium zinc oxide (IZO), and zinc oxide (ZnO). When the anode 110 is a reflective electrode, the anode 110 may have a reflective layer made of any one of aluminum (Al), silver (Ag), and nickel (Ni) under the layer made of any one of ITO, IZO, .

The hole injection layer 120 may function to smoothly inject holes from the anode 110 into the light emitting layer 140. The hole injection layer 120 of the present embodiment may use a heterocyclic compound represented by the following formula (1).

[Chemical Formula 1]

R 1 to R 6 are each independently selected from the group consisting of hydrogen, deuterium, halogen, cyano, trifluoromethyl, nitro, alkyl having 1 to 6 carbon atoms, alkoxy having 1 to 6 carbon atoms, An aryl group having 6 to 30 carbon atoms, and a heteroaryl group having 5 to 30 carbon atoms, which may be connected to each other to form a ring, and A is CH Or N, and X1 and X2 are each independently selected from among the compounds shown below, wherein Ar is an aryl group having 6 to 30 carbon atoms or a heteroaryl group having 5 to 30 carbon atoms.

The above-mentioned heterocyclic compound may be represented by the following general formula (2) or (3).

(2)

(3)

The heterocyclic compound represented by the above formula (1) binds functional groups X1 and X2 to fluorenes located on both sides of the heterocyclic compound to impart charge transport properties to the heterocyclic compound. Therefore, there is an advantage that the charge transport efficiency of the organic electroluminescent device can be improved and the driving voltage can be lowered.

The thickness of the hole injection layer 120 may be 1 to 150 nm. If the thickness of the hole injection layer 120 is 1 nm or more, the hole injection characteristics can be prevented from being degraded. If the thickness is 150 nm or less, the thickness of the hole injection layer 120 is too thick, There is an advantage that it is possible to prevent the drive voltage from rising.

The hole transport layer 130 plays a role of facilitating the transport of holes and may be formed by using NPD (N, N-dinaphthyl-N, N'-diphenyl benzidine), TPD (N, N'- N, N'-bis- (phenyl) -benzidine), s-TAD, and MTDATA (4,4 ', 4 "-tris (N-3-methylphenyl-N-phenylamino) -triphenylamine) The thickness of the hole transport layer 130 may be 1 to 150 nm. If the thickness of the hole transport layer 130 is 1 nm or more, the hole transport property may be deteriorated When the thickness is 150 nm or less, the thickness of the hole transport layer 130 is too thick, which is advantageous in preventing the driving voltage from rising to improve the movement of holes.

The light emitting layer 140 may emit red (R), green (G), or blue (B) light, and may be formed of a phosphor or a fluorescent material.

When the light emitting layer 140 is red, it includes a host material including CBP (carbazole biphenyl) or mCP (1,3-bis (carbazol-9-yl) wherein the dopant comprises at least one selected from the group consisting of iridium, iridium, PQIr (acac) (bis (1-phenylquinoline) acetylacetonate iridium), PQIr (tris (1-phenylquinoline) iridium) and PtOEP (octaethylporphyrin platinum) Or PBD: Eu (DBM) ₃ (Phen) or Perylene. However, the present invention is not limited thereto.

When the light emitting layer 140 is green, it may be composed of a phosphorescent material including a dopant material including a host material including CBP or mCP and containing Ir (ppy) 3 (fac tris (2-phenylpyridine) iridium) Alternatively, it may be made of a fluorescent material including Alq3 (tris (8-hydroxyquinolino) aluminum), but is not limited thereto.

When the light emitting layer 140 is blue, it may be made of a phosphorescent material including a host material including CBP or mCP and including a dopant material including (4,6-F ₂ ppy) ₂ Irpic, but is not limited to, a fluorescent material including any one selected from the group consisting of spiro-DPVBi, spiro-6P, distyrylbenzene (DSB), distyrylarylene (DSA), PFO polymer, and PPV polymer .

The electron transport layer 150 serves to smooth the transport of electrons and is made of at least one selected from the group consisting of Alq3 (tris (8-hydroxyquinolino) aluminum), PBD, TAZ, spiro-PBD, BAlq, But is not limited thereto. The thickness of the electron transport layer 150 may be 1 to 50 nm. If the thickness of the electron transporting layer 150 is 1 nm or more, the electron transporting property can be prevented from being degraded. If the thickness is 50 nm or less, the thickness of the electron transporting layer 150 is too thick, There is an advantage that the driving voltage can be prevented from rising.

The electron injection layer 160 serves to smooth the injection of electrons and may include Alq3 (tris (8-hydroxyquinolino) aluminum), PBD, TAZ, spiro-PBD, BAlq or SAlq. On the other hand, the electron injection layer 160 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 , but the present invention is not limited thereto. The thickness of the electron injection layer 160 may be 1 to 50 nm. If the thickness of the electron injection layer 160 is 1 nm or more, there is an advantage that the electron injection characteristics can be prevented from being degraded. If the thickness is 50 nm or less, the thickness of the electron injection layer 150 is too thick, There is an advantage that it is possible to prevent the drive voltage from rising.

The cathode 170 is an electron injection electrode and may be made of magnesium (Mg), calcium (Ca), aluminum (Al), silver (Ag), or an alloy thereof having a low work function. Here, when the organic electroluminescent device is a front or both-side light emitting structure, the cathode 170 may be formed to have a thickness thin enough to transmit light, and when the organic electroluminescent device is a back light emitting structure, It can be formed thick enough.

The organic electroluminescent device of FIG. 1 described above has shown and described that the hole injection layer is composed of the heterocyclic compound of the present invention. On the other hand, referring to FIG. 2, the heterocyclic compound 121 of the present invention may be doped in the hole transport layer 130. At this time, the heterocyclic compound (121) is doped with the doping concentration of 0.1 to 50% with respect to the hole transporting layer (130). The hole injection layer 120 may be formed from a group consisting of CuPc (cupper phthalocyanine), PEDOT (poly (3,4) -ethylenedioxythiophene), PANI (polyaniline), and NPD (N, N-dinaphthyl- But the present invention is not limited thereto.

3, the heterocyclic compound 121 may be included in the hole buffer layer 125 located between the hole injection layer 120 and the hole transport layer 130. Referring to FIG. The hole buffer layer 125 may be formed of only the heterocyclic compound 121 or may be doped with the heterocyclic compound 121. At this time, the matrix material of the hole buffer layer 125 may be, for example, a hole transport layer material, but is not limited thereto. The hole buffer layer 125 is located in the hole injection layer 120 and the hole transport layer 130 and functions as a buffer layer. Although not shown, the hole buffer layer 125 is in contact with the anode 110 between the anode 110 and the hole transport layer 130, and the hole injection layer 120 may be omitted.

As described above, the heterocyclic compound of the present invention is applied to at least one of a hole injection layer, a hole transporting layer doping and a hole buffer layer so that functional groups are bonded to fluorenes located on both sides of the heterocyclic compound to form a heterocyclic compound Thereby imparting a hole injection characteristic. Therefore, there is an advantage that the charge transport efficiency of the organic electroluminescent device can be improved and the driving voltage can be lowered.

4 to 6 are views showing an organic electroluminescent device according to a second embodiment of the present invention. In the following, description of the same components as those of the first embodiment will be omitted.

4, the organic electroluminescent device 200 includes a plurality of light emitting units ST1 and ST2 disposed between the anode 210 and the cathode 310 and a plurality of light emitting units ST1 and ST2 disposed between the plurality of light emitting units ST1 and ST2. And a charge generating layer 260 located in the charge generating layer 260.

In more detail, the first light emitting portion ST1 constitutes one light emitting element unit and includes a first light emitting layer 240. [ The first light emitting layer 240 may emit light of any one of red, green, and blue. In this embodiment, the first light emitting layer 240 may be a blue light emitting layer emitting blue light. The first light emitting portion ST1 further includes a hole injection layer 220 and a first hole transport layer 230 between the anode 210 and the first light emitting layer 240. [ The hole injection layer 220 may function to smoothly inject holes from the anode 210 into the first light emitting layer 240 and may be formed of cupper phthalocyanine (CuPc), poly (3,4) -ethylenedioxythiophene (PEDOT) , PANI (polyaniline) and NPD (N, N-dinaphthyl-N, N'-diphenyl benzidine).

The first hole transport layer 230 has the same structure as the hole transport layer of the first embodiment described above. The first light emitting portion ST1 further includes a first electron transport layer 250 on the first light emitting layer 240. [ The first electron transporting layer 250 has the same structure as the electron transporting layer of the first embodiment described above. The first light emitting portion ST1 including the hole injection layer 220, the first hole transport layer 230, the first light emitting layer 240 and the first electron transport layer 250 is formed on the anode 210 .

A charge generation layer (CGL) 260 is disposed on the first light emitting portion ST1. The charge generation layer 260 may be a PN junction charge generation layer in which an N-type charge generation layer 260N and a P-type charge generation layer 260P are bonded. At this time, the PN junction charge generation layer 260 generates charges or separates them into holes and electrons, and injects charges into the respective light emitting layers. That is, the N-type charge generation layer 260N supplies electrons to the first light emitting layer 240 adjacent to the anode, and the P-type charge generation layer 260P supplies electrons to the second light emitting layer 290 of the second light emitting portion ST2. The luminous efficiency of the organic electroluminescent device having a plurality of light emitting layers can be further increased and the driving voltage can be lowered.

Here, the P-type charge generation layer 260P is composed of the heterocyclic compound represented by the above-mentioned formula (1). The heterocyclic compound of the present invention binds functional groups on fluorine at both sides of the heterocyclic compound to impart charge transport properties to the heterocyclic compound. Therefore, by including the heterocyclic compound in the P-type charge generation layer 260P, the charge transport efficiency of the P-type charge generation layer 260P can be improved and the driving voltage of the organic electroluminescence device can be lowered.

The N-type charge generation layer 260N may be formed of a metal or an N-type doped organic material. 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. The N-type dopant used for the organic material doped with the N-type material and the host material may be a commonly used material. 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 selected from the group consisting of Cs, K, Rb, Mg, Na, Ca, Sr, Eu and Yb. The host material may be an organic material having a hetero ring containing a nitrogen atom and having from 20 to 60 carbon atoms, and examples thereof include tris (8-hydroxyquinoline) aluminum, triazine, hydroxyquinoline derivatives, and benzazole Derivatives, and silole derivatives.

On the other hand, the second light emitting portion ST2 including the second light emitting layer 290 is located on the charge generating layer 260. [ The second light emitting layer 290 may emit light of one of red, green, and blue. For example, the second light emitting layer 290 may be a yellow light emitting layer that emits yellow light in this embodiment. The yellow luminescent layer may have a multilayer structure of a luminescent layer emitting yellow-green or a luminescent layer emitting yellow and a green luminescent layer. In this embodiment, a single layer structure of a yellow light emitting layer for emitting yellow green is described as an example. The second light emitting layer 290 may be formed of CBP (4,4'-N, N'-dicarbazolebiphenyl) or Balq (Bis (2-methyl-8-quinlinolato-N1, O8) - (1,1'-Biphenyl- ) aluminum). The phosphorescent yellow green dopant may emit yellow green.

The second light emitting portion ST2 further includes a second hole transporting layer 270 and an electron blocking layer 280 between the charge generating layer 260 and the second light emitting layer 290. The second hole transport layer 270 has the same structure as the first hole transport layer 230 described above. The electron block layer 280 is formed of a material of the hole transporting layer and a metal or a metal compound so as to prevent electrons generated in the light emitting layer from flowing to the hole transporting layer. Therefore, the LUMO level of the electronic block layer becomes high, and the electrons can not fall over.

The second light emitting portion ST2 further includes a second electron transport layer 300 on the second light emitting layer 290 and the second electron transport layer 300 includes the first light emitting portion ST1, And has the same structure as the electron transport layer 250. Therefore, the second light emitting portion ST2 including the second hole transporting layer 270, the electron blocking layer 280, the second light emitting layer 290, and the second electron transporting layer 300 is formed on the charge generating layer 260 . And a cathode 310 is provided on the second light emitting portion ST2 to constitute an organic electroluminescent device according to the second embodiment of the present invention.

The organic electroluminescent device of FIG. 4 described above has shown and described that the P-type charge generation layer 260P is composed of the heterocyclic compound of the present invention. On the other hand, referring to FIG. 5, the heterocyclic compound 121 of the present invention may be doped into a P-type charge generation layer 260P made of a matrix material. That is, the P-type charge generation layer 260P may be composed of the matrix material and the heterocyclic compound 121. Since the matrix material has been described in the first embodiment, it is omitted. At this time, the heterocyclic compound 121 is doped with a doping concentration of 0.1 to 50% with respect to the P-type charge generation layer 260P. Referring to FIG. 6, the heterocyclic compound 121 of the present invention is doped to the P-type charge generation layer 260P and is used between the P-type charge generation layer 260P and the second light emitting layer 290 The hole transporting layer may be omitted.

On the other hand, in the second embodiment of the present invention, the use of the heterocyclic compound of the present invention in the P-type charge generation layer of the organic electroluminescent device is disclosed. In the hole injection layer formed in the first light emitting portion of the second embodiment, As in the first embodiment, a heterocyclic compound may further be used. That is, the configuration of the first embodiment described above in the second embodiment of the present invention may be appropriately mixed and used.

As described above, the heterocyclic compound of the present invention has an advantage of improving the charge transport efficiency and lowering the driving voltage of the organic electroluminescent device by applying the heterocyclic compound to the P-type charge generation layer.

7 and 8 are views showing an organic electroluminescent device according to a third embodiment of the present invention. In the following description, the same constituent elements as those of the second embodiment are denoted by the same reference numerals, and a description thereof will be omitted.

7, the organic electroluminescent device 200 includes a plurality of light emitting units ST1, ST2, and ST3 disposed between the anode 210 and the cathode 310, and a plurality of light emitting units ST1 and ST2 , And ST3), and a second charge generation layer (320). Although three light emitting portions are shown between the anode 210 and the cathode 310 in the present embodiment, the present invention is not limited thereto and four or more light emitting portions may be disposed between the anode 210 and the cathode 310 .

In more detail, the first light emitting portion ST1 constitutes one light emitting element unit and includes a first light emitting layer 240. [ The first light emitting layer 240 may emit light of any one of red, green, and blue. In this embodiment, the first light emitting layer 240 may be a blue light emitting layer emitting blue light. The first light emitting portion ST1 further includes a hole injection layer 220 and a first hole transport layer 230 between the anode 210 and the first light emitting layer 240. [ The first light emitting portion ST1 further includes a first electron transport layer 250 on the first light emitting layer 240. [ The first light emitting portion ST1 including the hole injection layer 220, the first hole transport layer 230, the first light emitting layer 240 and the first electron transport layer 250 is formed on the anode 210 .

A first charge generating layer 260 is positioned on the first light emitting portion ST1. The first charge generation layer 260 is a PN junction charge generation layer in which an N-type charge generation layer 260N and a P-type charge generation layer 260P are bonded to each other to generate charges or separate them into holes and electrons, Charge the charge. Here, the P-type charge generation layer 260P is composed of a heterocyclic compound represented by the general formula (1) as in the second embodiment described above. The heterocyclic compound of the present invention binds functional groups on fluorine at both sides of the heterocyclic compound to impart charge transport properties to the heterocyclic compound. Therefore, by including the heterocyclic compound in the P-type charge generation layer 260P, the charge transport efficiency of the P-type charge generation layer 260P can be improved and the driving voltage of the organic electroluminescence device can be lowered. The N-type charge generation layer 260N is configured in the same manner as in the second embodiment described above.

On the other hand, a second light emitting portion ST2 including a second light emitting layer 290 is located on the first charge generating layer 260. The second light emitting layer 290 may emit light of one of red, green, and blue colors. For example, the second light emitting layer 290 may be a yellow light emitting layer that emits yellow light in this embodiment. The second light emitting portion ST2 further includes a second hole transporting layer 270 and an electron blocking layer 280 between the first charge generating layer 260 and the second light emitting layer 290, 290). ≪ / RTI > The second light emitting portion ST2 including the second hole transporting layer 270, the electron blocking layer 280, the second light emitting layer 290 and the second electron transporting layer 300 is formed on the first charge generating layer 260, ).

And the second charge generating layer 320 is positioned on the second light emitting portion ST2. The second charge generating layer 320 is a PN junction charge generating layer in which an N-type charge generating layer 320N and a P-type charge generating layer 320P are bonded to each other. Charge is generated or separated into holes and electrons, Charge the charge. Here, the P-type charge generation layer 320P is composed of the heterocyclic compound represented by the above formula (1) in the same manner as the P-type charge generation layer 260P of the first charge generation layer 260 described above. The N-type charge generation layer 320N is formed in the same manner as the N-type charge generation layer 260N of the first charge generation layer 260.

On the other hand, a third light emitting portion ST3 including a third light emitting layer 340 is disposed on the second charge generating layer 320. [ The third light emitting layer 340 may emit light of one of red, green, and blue colors. For example, the third light emitting layer 340 may be a blue light emitting layer that emits blue light in this embodiment. The third light emitting portion ST3 further includes a third hole transporting layer 330 between the second charge generating layer 320 and the third light emitting layer 340, Transport layer 350 and an electron injection layer 360. [ The third light emitting portion ST3 including the third hole transporting layer 330, the third light emitting layer 340, the third electron transporting layer 350 and the electron injection layer 360 is formed on the second charge generating layer 320, ). And a cathode 310 is provided on the third light emitting portion ST3 to constitute an organic electroluminescent device according to the third embodiment of the present invention.

The organic electroluminescent device of FIG. 7 described above has shown and described that the P-type charge generation layers 260P and 320P are composed of the heterocyclic compound of the present invention. On the other hand, referring to FIG. 8, the heterocyclic compound 121 of the present invention may be doped into P-type charge generation layers 260P and 320P made of a matrix material. That is, the P-type charge generation layers 260P and 320P may be composed of the matrix material and the heterocyclic compound 121. Since the matrix material has been described in the first embodiment, it is omitted. At this time, the heterocyclic compound 121 is doped with a doping concentration of 0.1 to 50% with respect to the P-type charge generation layers 260P and 320P. Although not shown, the heterocyclic compound 121 of the present invention is doped to the P-type charge generation layers 260P and 320P, and the P-type charge generation layer 260P of the first charge generation layer 260 The hole transport layer may be omitted between the second emission layer 290 and the P-type charge generation layer 320P of the second charge generation layer 320 and the third emission layer 340.

Meanwhile, in the third embodiment of the present invention, the use of the heterocyclic compound of the present invention in the P-type charge generation layers of the first charge generation layer and the second charge generation layer of the organic electroluminescent device has been disclosed. However, And the heterocyclic compound may be contained in only one of the P-type charge generating layer of the first charge generating layer and the second charge generating layer. Further, in the present invention, a heterocyclic compound may be further added to the hole injection layer formed in the first light emitting portion of the third embodiment, as in the first embodiment described above. That is, the configuration of the first embodiment described above in the third embodiment of the present invention may be appropriately mixed and used.

As described above, the heterocyclic compound of the present invention can be applied to a P-type charge generation layer, whereby an organic electroluminescent device capable of lowering a driving voltage by inducing an increase in efficiency of a device by a heterocyclic compound having charge- There is an advantage that can be provided.

Examples of the synthesis of the heterocyclic compound of the present invention and the organic electroluminescent device including the same will be described below in the following Synthesis Examples and Examples. However, the following examples are illustrative of the present invention, but the present invention is not limited to the following examples.

Synthetic example

1) Synthesis of Compound A

To a 250 ml round bottom flask was added 2-bromo-9H-fluoren-9-one (5.0 g, 19.3 mmol), 2- (4,4,5,5- 2- (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) -9H- 2-yl) -9H-fluoren-9-one (6.5 g, 21.2 mmol) was dissolved in 150 ml of tetrahydrofuran (THF). Tetrakis (triphenylphosphine) palladium _{(PPh 3) 4) (0.45g} , 0.39mmol), 2M potassium carbonate (K ₂ CO ₃₎ put as a solution 30ml and the mixture was stirred under reflux for 15 hours under an argon atmosphere. After completion of the reaction, the solution was distilled under reduced pressure to remove tetrahydrofuran, extracted with ethyl acetate, and the organic matter was distilled off under reduced pressure. Compound A-1 was isolated from the residue by column chromatography.

Compound A-1 (5.0 g, 14.0 mmol), malononitrile (3.7 g, 56.0 mmol) and 200 ml of chlorobenzene were placed in a 500 ml round bottom flask and stirred under a nitrogen atmosphere for 30 minutes. Titanium tetrachloride (TiCl ₄ ) (1M in CH ₂ Cl ₂ , 56.0 ml) was slowly added dropwise thereto, and 10 ml of pyridine was further added thereto, followed by stirring for 10 hours to complete the reaction. 20 ml of distilled water was added to the reaction solution, and the mixture was stirred for 30 minutes. Then, the volatiles were removed by distillation under reduced pressure, and the remaining solid was washed with dichloromethane and filtered. The filtered solid was sublimed under vacuum to obtain Compound A.

2) Synthesis of compound B

2-bromo-5-chlorobenzoic acid (4.0 g, 17.0 mmol) and 4- (trifluoromethyl) phenylboronic acid were added to a 250 ml round bottom flask. ) phenylboronic acid) (3.9g, 20.4mmol ) under the tetrahydrofuran is dissolved into a 150ml, where the _{Pd (PPh 3) 4 (0.39g} , 0.34mmol), 2M K 2 CO 3 aqueous solution into the atmosphere, such as argon 30ml 48 Lt; / RTI > The solution was then acid treated, extracted with ethyl acetate, and distilled under reduced pressure to remove the solvent and volatiles. The compound B-4 was isolated from the residue by column chromatography.

Compound B-4 (5.0 g, 16.6 mmol) and sulfuric acid (H ₂ SO ₄ ) (50 ml) were added to a 100 ml round bottom flask and stirred for 10 hours. The precipitate, compound B-3, was obtained by gradually dropping the reaction solution into a 500 ml beaker containing ice water, and the precipitate was filtered and washed with water to carry out the next reaction without further purification.

(Dibenzylideneacetone) palladium (0) (Pd (dba) ₂ ) (0.49 g, 0.85 mmol) and tricyclohexyl phosphine (0.57 g, 2.0 mmol) were placed in a 100 ml round- After dissolving in 40 ml of dioxane, nitrogen gas was blown into the solution for 20 minutes. (4.0g, 14.2mmol), bis (pinacolato) diboron (4.0g, 15.6mmol) and KOAc (2.1g, 21.2mmol) were added to the solution, and 20ml of dioxane The mixture was further stirred and then stirred at 80 DEG C for 15 hours. After completion of the reaction, the solution was distilled under reduced pressure to remove the solvent. The reaction mixture was extracted with ethyl acetate, and the organic matter was distilled off under reduced pressure. Compound B-2 was isolated from the residue by column chromatography.

Tris (dibenzylideneacetone) dipalladium (0) (Pd ₂ (dba) ₃ ) (0.49 g, 0.53 mmol) and tricyclohexylphosphine (0.36 g, 1.3 mmol) were placed in a 100 ml round bottom flask and 40 ml of dioxane , And then nitrogen gas was blown into the solution for 20 minutes. Here reflux and stirred for a compound B-3 (3.0g, 10.6mmol) , into a compound B-2 (4.4g, 11.7mmol) , then gave 1M potassium phosphate (K ₃ PO ₄₎ put as a solution 16 15ml sigan . After the completion of the reaction, the solution was distilled under reduced pressure to remove the solvent, which was filtered through silica using dichloromethane and tetrahydrofuran. The target compound B-1 was obtained through recrystallization with a filtered solvent.

Compound B-1 (3.0 g, 6.1 mmol), malononitrile (1.6 g, 24.3 mmol) and 150 ml of chlorobenzene were placed in a 250 ml round bottom flask and stirred under a nitrogen atmosphere for 30 minutes. Titanium tetrachloride (1M in CH ₂ Cl ₂ , 24.3 ml) was slowly added dropwise thereto, and 4 ml of pyridine was further added thereto, followed by stirring for 8 hours to complete the reaction. 20 ml of distilled water was added to the reaction solution, and the mixture was stirred for 30 minutes. Then, the volatiles were removed by distillation under reduced pressure, and the remaining solid was washed with dichloromethane and filtered. The filtered solid was sublimed under vacuum to give the final compound B.

The differential scanning calorimetry (DSC) of the prepared compound B was performed. The results are shown in FIG. 9, and thermogravimetric analysis (TGA) was performed. The results are shown in FIG. 10 . The results of DSC and TGA of the compound B of the present invention were obtained by raising the temperature from 25 ° C to 500 ° C.

Referring to FIG. 9, DSC measurement of the compound B of the present invention confirmed that it remained thermally stable until it was decomposed at around 400 ° C. Referring to FIG. 10, it was confirmed that the TGA of the compound B of the present invention maintained a thermally stable state until the molecular weight decreased around 360 degrees. That is, it was confirmed that the compound B of the present invention exhibits a thermal stability of at least 360 degrees.

Hereinafter, embodiments in which an organic electroluminescent device including the compound B prepared in the above-mentioned synthesis example is produced are disclosed. The thickness and formation conditions of the organic layers below do not limit the scope of the present invention.

≪ Example 1 >

The ITO substrate was patterned to have a light emitting area of 2 mm x 2 mm, and then cleaned with UV ozone. After the substrate was mounted in a vacuum chamber, the base pressure was adjusted to 5 to 7 x 10 < ^-8 > torr, and the following layers were deposited by evaporation from the heating boat in the following order.

(1) Compound B was doped in NPD at a concentration of 5% to form a hole injection layer having a thickness of 100 ANGSTROM,

(2) NPD was formed to a thickness of 800 ANGSTROM as a hole transport layer,

(3) a blue light emitting layer was doped with a blue dopant to a blue host at a doping concentration of 5% to a thickness of 200 ANGSTROM,

(4) ETM: Liq was co-deposited as an electron transport layer at a thickness of 120 ANGSTROM by co-

(5) LiF was formed to a thickness of 5 A as an electron injection layer,

(6) Al was formed to a thickness of 1000 Å as a cathode.

After deposition of these layers, an organic electroluminescent device was fabricated by transferring the film from the deposition chamber into a dry box for subsequent film formation and subsequently encapsulating the film using a UV curing epoxy and a moisture getter.

≪ Example 2 >

An organic electroluminescent device was fabricated by differentiating NPD with compound B at a concentration of 10% to form a hole injection layer with a thickness of 100 Å under the same process conditions as in Example 1 described above.

<Comparative Example>

Except that a hole injecting layer and a hole transporting layer were deposited to a thickness of 900 Å in NPD to form a single layer under the same process conditions as in Example 1 described above to fabricate an organic electroluminescent device.

The driving voltage, the current density, the current efficiency, the external quantum efficiency and the color coordinates of the organic electroluminescent device fabricated according to Examples 1 and 2 and Comparative Examples were measured and shown in Table 1 below. The relationship between the voltage and the current density was FIG. 11 shows the relationship between the current efficiency and the luminance efficiency, and FIG. 13 shows the relationship between the current density and the luminance.

Driving voltage
(V)
Current density
(mA / cm 2) Current efficiency
(cd / A)
External quantum efficiency (%)
Color coordinates CIE_x CIE_y Comparative Example 4.67 10 3.8 4.3 0.145 0.095 Example 1 4.03 10 3.8 4.3 0.145 0.096 Example 2 4.05 10 3.8 4.3 0.145 0.096

Referring to Table 1, in Examples 1 and 2 in which the compound B is contained in the hole injection layer, the driving voltage is lowered while showing the same level of current density, current efficiency, color coordinates and external quantum efficiency as compared with the comparative example appear.

Referring to FIG. 11, in Examples 1 and 2, the current density according to the driving voltage was improved as compared with the comparative example, and Example 1 in which the compound B was included in the hole injection layer at 5% It was found that the current density according to the driving voltage was further improved than in Example 2.

12, the luminance efficiency according to the current density was improved in Examples 1 and 2 compared to the comparative example, and the luminance efficiency according to Example 2 in which the compound B was contained in 10% in the hole injection layer was 5% The luminance efficiency according to the current density was further improved.

Referring to FIG. 13, in Examples 1 and 2, the luminance according to the current density was improved as compared with the comparative example, and in Example 5 where 5% of the compound 2 was contained in the hole injection layer at 10% 1, the luminance was more improved according to the current density.

As described above, the present invention has an advantage of improving the charge transport efficiency of an organic electroluminescent device and lowering a driving voltage by including a heterocyclic compound having a novel structure having excellent thermal stability and charge transporting characteristics.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be practiced. It is therefore to be understood that the embodiments described above are to be considered in all respects only as illustrative and not restrictive. In addition, the scope of the present invention is indicated by the following claims rather than the detailed description. Also, all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

100: organic electroluminescent device 110: anode
120: Hole injection layer 130: Hole transport layer
140: light emitting layer 150: electron transporting layer
160: electron injection layer 170: cathode

Claims (18)

A heterocyclic compound represented by the following formula (1).
[Chemical Formula 1]

In Formula 1,
Each of R1 to R6 independently represents hydrogen, deuterium, halogen, cyano, trifluoromethyl, nitro, alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 6 carbon atoms, A cycloalkyl group, an aryl group having 6 to 30 carbon atoms, and a heteroaryl group having 5 to 30 carbon atoms, which may be connected to each other to form a ring,
A is CH or N,
X1 and X2 are each independently selected from among the compounds shown below, wherein Ar is an aryl group having 6 to 30 carbon atoms or a heteroaryl group having 5 to 30 carbon atoms.

The method according to claim 1,
The heterocyclic compound is represented by the following general formula (2) or (3).
(2)

(3)

A light emitting layer between the anode and the cathode, and at least one organic layer between the anode and the light emitting layer,
Wherein the organic layer comprises the heterocyclic compound according to any one of claims 1 and 2.
The method according to claim 1,
Wherein the organic layer is at least one selected from the group consisting of a hole injection layer, a hole transport layer and a hole buffer layer.
5. The method of claim 4,
Wherein the hole injection layer comprises only the heterocyclic compound.
5. The method of claim 4,
Wherein the hole buffer layer is disposed between the hole injection layer and the hole transport layer and is in contact with the anode.
5. The method of claim 4,
Wherein the hole buffer layer is positioned between the hole injection layer and the hole transport layer.
8. The method according to claim 6 or 7,
Wherein the hole buffer layer comprises only the heterocyclic compound, or is composed of a matrix material and the heterocyclic compound.
9. The method of claim 8,
Wherein the matrix material is the hole transport layer material.
5. The method of claim 4,
Wherein the hole transport layer is located on the hole injection layer, and the hole transport layer is composed of the hole transport layer material and the heterocyclic compound.
The first light emitting portion including a first light emitting layer between an anode and a cathode;
The second light emitting portion including a second light emitting layer on the first light emitting portion; And
And a charge generation layer disposed between the first light emitting portion and the second light emitting portion,
Wherein the charge generation layer comprises an N-type charge generation layer and a P-type charge generation layer,
Wherein the P-type charge generation layer comprises the heterocyclic compound according to any one of claims 1 and 2.
12. The method of claim 11,
Wherein the first light emitting portion includes at least one organic layer positioned between the anode and the first light emitting layer, wherein the organic layer is at least one of a hole injection layer, a first hole transport layer, and a hole buffer layer. .
13. The method according to claim 11 or 12,
Wherein the first light emitting portion comprises a first hole transporting layer, and the P-type charge generating layer comprises only the heterocyclic compound, or is composed of a matrix material and the heterocyclic compound.
14. The method of claim 13,
Wherein the matrix material is the hole transport layer material.
14. The method of claim 13,
And the second light emitting portion includes a second hole transporting layer positioned between the P-type charge generating layer and the second light emitting layer.
14. The method of claim 13,
And the P-type charge generation layer is in contact with the second light emitting layer.
12. The method of claim 11,
And a third light emitting portion including a third light emitting layer is further formed on the second light emitting portion.
18. The method of claim 17,
Wherein the first light emitting portion and the third light emitting portion are a blue light emitting layer, and the second light emitting portion is a yellow or yellow green light emitting layer.

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