KR101785724B1 - Compound For Electron Transporting And Organic Light Emitting Diode Device Comprising The Same - Google Patents

Abstract

The present invention relates to an electron transport compound represented by the following general formula (1) or (2).

Wherein R1 and R2 each independently represent a substituted or unsubstituted aromatic ring group having 6 to 20 carbon atoms, R3 represents at least one nitrogen, sulfur or oxygen atom, And an unsubstituted or substituted ring group having 5 to 19 carbon atoms.

Organic electroluminescent device

Description

[0001] The present invention relates to an electron transport compound and an organic electroluminescent device including the same. ≪ RTI ID = 0.0 > [0002]

The present invention relates to an organic electroluminescent device, and more particularly, to an organic electroluminescent device including a novel hole transporting compound.

2. Description of the Related Art In recent years, the importance of flat panel displays (FPDs) has been increasing with the development of multimedia. In response to this, various kinds of devices such as a liquid crystal display (LCD), a plasma display panel (PDP), a field emission display (FED), an organic light emitting device A flat display of a flat panel display has been put into practical use.

Particularly, the organic electroluminescent device has a response speed of 1 ms or less, a high response speed, low power consumption, and self-emission. In addition, there is no problem in the viewing angle, which is advantageous as a moving picture display medium regardless of the size of the apparatus. In addition, since it can be manufactured at a low temperature and the manufacturing process is simple based on the existing semiconductor process technology, it is attracting attention as a next generation flat panel display device.

The organic electroluminescent device may have a structure in which an anode, a hole injecting layer, a hole transporting layer, a light emitting layer, an electron transporting layer, an electron injecting layer, and a cathode are sequentially stacked. Therefore, the holes supplied from the anode and the electrons received from the cathode combine in the light emitting layer to form an exciton, which is a hole-electron pair, and emit light by energy generated when the exciton returns to the ground state.

However, the conventional organic electroluminescent device has a problem in that the moving speed of electrons is slower than the moving speed of holes, and the ratio of electrons and holes meeting in the emitting layer is low, resulting in a decrease in luminous efficiency. In addition, since the energy band does not match between the light emitting layer and the electron transporting layer, there is a problem that electron injection into the light emitting layer is not easy.

The present invention provides an electron transport compound capable of improving the luminous efficiency and an organic electroluminescent device including the same.

In order to achieve the above object, an electron transport compound according to an embodiment of the present invention may be represented by the following formula (1) or (2).

[Chemical Formula 1]

(2)

Wherein R1 and R2 each independently represent a substituted or unsubstituted aromatic ring group having 6 to 20 carbon atoms, R3 represents at least one nitrogen, sulfur or oxygen atom, And an unsubstituted or substituted ring group having 5 to 19 carbon atoms.

The aromatic ring group may be any one selected from the group consisting of phenyl, biphenyl, naphthyl, terphenyl, anthracene, phenanthrene, pyrene and fluorocene.

When the aromatic ring group is substituted, the substituent of the aromatic ring group may be any one selected from the group consisting of methyl, ethyl, isopropyl, tetrabutyl, cyclohexyl, methoxy, ethoxy, fluoride and cyano.

The modified ring group may be any one selected from the group consisting of pyridyl, quinoline, isoquinoline, phenanthroline and quinoxaline.

When the above-mentioned heterocyclic group is substituted, the substituent of the above-mentioned heterocyclic group may be a methyl group.

Each of R 1 and R 2 may independently be selected from any of the following materials.

The R3 may be any one selected from the following materials.

The organic electroluminescent device according to one embodiment of the present invention includes an anode, a hole injecting layer, a hole transporting layer, a light emitting layer, an electron transporting layer, an electron injecting layer, and a cathode, And an electron transport compound according to any of claims 1 to 7.

The electron transport compound and the organic electroluminescent device including the same of the present invention have an advantage that the luminance of the organic electroluminescent device can be improved and the driving voltage can be lowered. Therefore, there is an advantage that the luminous efficiency of the organic electroluminescent device can be improved.

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

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

1, an organic electroluminescent device 100 according to an embodiment of the present invention includes an anode 110, a hole injection layer 120, a hole transport layer 130, a light emitting layer 140, an electron transport layer 150, An electron injecting layer 160, and a cathode 170. [0033]

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 may be formed of cupper phthalocyanine (CuPc), poly (3,4) -ethylenedioxythiophene (PEDOT) polyaniline and NPD (N, N-dinaphthyl-N, N'-diphenyl benzidine), but the present invention is not limited thereto.

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) But it is not limited thereto.

The thickness of the hole transport layer 130 may be 1 to 150 nm. Here, if the thickness of the hole transport layer 130 is 5 nm or more, the hole transport property can be prevented from being lowered. If the thickness is 150 nm or less, the thickness of the hole transport layer 130 is too thick, There is an advantage that the driving voltage can be prevented from rising.

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) a phosphorescent dopant including 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 may serve to facilitate the injection of electrons from the cathode 170 into the light emitting layer 140, and may include an electron transport compound represented by the following general formula (1) or (2).

[Chemical Formula 1]

(2)

Wherein R1 and R2 each independently represent a substituted or unsubstituted aromatic ring group having 6 to 20 carbon atoms, R3 represents at least one nitrogen, sulfur or oxygen atom, And an unsubstituted or substituted ring group having 5 to 19 carbon atoms.

Here, the aromatic ring group may be any one selected from the group consisting of phenyl, biphenyl, naphthyl, terphenyl, anthracene, phenanthrene, pyrene and fluorocene. When the aromatic ring group is substituted, the substituent of the aromatic ring group may be any one selected from the group consisting of methyl, ethyl, isopropyl, tetrabutyl, cyclohexyl, methoxy, ethoxy, fluoride and cyano .

The modified ring group may be any one selected from the group consisting of pyridyl, quinoline, isoquinoline, phenanthroline and quinoxaline. When the aliphatic cyclic group is substituted, the substituent of the aliphatic cyclic group may be a methyl group.

Each of R 1 and R 2 may independently be selected from any of the following materials.

The R3 may be any one selected from the following materials.

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.

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, the anode 170 may be formed to have a thickness thin enough to transmit light when the organic electroluminescent device is a front or both-side light emitting structure, and when the organic electroluminescent device is a back light emitting structure, It can be formed thick enough.

Hereinafter, the synthesis examples of the electron transport compound of the present invention and the organic electroluminescent device including the compound will be described in detail in Synthesis Examples and Examples below. 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 ETM-01

In a two-necked round bottom flask, 9,10-diphenyl-2,6-dibromoanthracene (10 g, 0.022 mol), pyridylphenylamine (7.65 g, , 0.045 mol), BINAP ([2,2'-Bis (diphenylphosphino) -1,1'-binaphthyl]) (0.010 g, 1 mol%), Pd (OAC) ₂ [Palladium , 1% mol) and NaOtBu [Sodium tert-butoxide] (8.1 g, 0.06 mol) were dissolved in toluene (80 mL) and refluxed for 24 hours. When the reaction is complete, cool the round bottom flask, remove toluene (40 mL) as a reaction solvent, and add methanol (100 mL) to form a precipitate. This was filtered and recrystallized using dichloromethane and methanol to give the final product.

2) Synthesis of ETM-02

In a two-necked round bottom flask, 9,10-diphenyl-2,6-dibromoanthracene (10 g, 0.022 mol), pyridylterphenylamine (N-pyridyl -3,5-diphenyl aniline) (15g, 0.045mol), BINAP ([2,2'-Bis (diphenylphosphino) -1,1'-binaphthyl]) (0.010g, 1% mol), Pd (OAC) 2 [Palladium (II) acetate] (0.040 g, 1 mol%) and NaOtBu [Sodium tert-butoxide] (8.1 g, 0.06 mol) were dissolved in toluene (80 mL) and refluxed for 24 hours. When the reaction is complete, cool the round bottom flask, remove toluene (40 mL) as a reaction solvent, and add methanol (100 mL) to form a precipitate. This was filtered and recrystallized using dichloromethane and methanol to give the final product.

3) Synthesis of ETM-03

In a two-neck round bottom flask, 9,10-dinaphthyl-2-bromoanthracene (12 g, 0.024 mol), pyridylnaphthylamine (6.2 g, 0.029 mol), BINAP ([2,2'- Bis (diphenylphosphino) -1,1'-binaphthyl]) (0.010g, 1% mol), Pd (OAC) 2 [Palladium (II) acetate] (0.040g, 1 % mol) and NaOtBu [Sodium tert-butoxide] (6.8 g, 0.05 mol) were dissolved in toluene (80 mL) and refluxed for 18 hours. When the reaction is complete, cool the round bottom flask, remove toluene (40 mL) as a reaction solvent, and add methanol (100 mL) to form a precipitate. This was filtered and recrystallized using dichloromethane and methanol to give the final product.

4) Synthesis of ETM-04

In a two-necked round bottom flask, 9,10-dibiphenyl-2-bromoanthracene (8 g, 0.014 mol), quinolylphenylamine (3.74 g, 0.017 mol), BINAP ([2,2'- Bis (diphenylphosphino) -1,1'-binaphthyl]) (0.010g, 1% mol), Pd (OAC) 2 [Palladium (II) acetate] (0.040g, 1 % mol) and NaOtBu [Sodium tert-butoxide] (4 g, 0.03 mol) were dissolved in toluene (80 mL) and refluxed for 18 hours. When the reaction is complete, cool the round bottom flask, remove toluene (40 mL) as a reaction solvent, and add methanol (100 mL) to form a precipitate. This was filtered and recrystallized using dichloromethane and methanol to give the final product.

Example

Hereinafter, embodiments in which an electron transport compound of the present invention represented by ETM-01 to ETM-04 described above are used as an electron transport layer to manufacture an organic electroluminescent device are described.

≪ Example 1 >

The ITO glass was patterned so as to have a light emitting area of 2 mm x 2 mm and then cleaned. After the substrate was mounted in a vacuum chamber, the base pressure was adjusted to 1 × 10 ^-6 torr. Then, DNTPD as a hole injection layer was formed to a thickness of 650 Å on the anode ITO, NPD as a hole transport layer was formed to a thickness of 400 Å, And a dopant, GD-1, at a concentration of 2%. Next, a compound represented by ETM-01 was formed as an electron transport layer to a thickness of 350 Å, an electron injection layer of LiF was formed to a thickness of 5 Å, and an anode of Al to a thickness of 1000 Å to form an organic electroluminescent device .

≪ Example 2 >

An organic electroluminescent device was fabricated under the same conditions as in Example 1 described above except that only the electron transport layer was changed to a compound represented by ETM-02.

≪ Example 3 >

An organic electroluminescent device was fabricated under the same conditions as in Example 1 described above except that the electron transport layer was different from the compound represented by ETM-03.

<Example 4>

An organic electroluminescent device was fabricated under the same conditions as in Example 1, except that the compound represented by ETM-04 was different only in the electron transporting layer.

<Comparative Example>

An organic electroluminescent device was fabricated by differentiating only the electron transporting layer with Alq ₃ under the same conditions as in Example 1 described above.

The current density, luminance, driving voltage and color coordinates of the organic electroluminescent device manufactured according to Examples 1 to 4 and Comparative Examples were measured and are shown in Table 1 below.

Current density
(mA / cm 2) Driving voltage
(V) Luminance
(cd / m 2) Color coordinates CIE (X) CIE (Y) Example 1 10 5.7 2210 0.308 0.621 Example 2 10 5.9 2330 0.310 0.618 Example 3 10 5.6 2216 0.310 0.620 Example 4 10 6.1 2456 0.310 0.618 Comparative Example 1 10 7.3 1350 0.318 0.588

As shown in Table 1, the organic electroluminescent devices manufactured according to Examples 1 to 4 exhibited better color coordinates than the comparative example. The driving voltage was remarkably lowered as compared with the comparative example, Which is significantly improved compared with that of the first embodiment.

Accordingly, the electron transport compound and the organic electroluminescent device including the electron transport compound according to an embodiment of the present invention have an advantage that the luminance can be improved and the driving voltage can be lowered compared with the conventional organic electroluminescent device. Therefore, there is an advantage that an organic electroluminescent device having excellent luminous efficiency can be provided.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments thereof, 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.

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

Claims (8)

An electron transport compound represented by the following formula (2). (2)

In Formula 2, R1 is phenyl, R &lt; 2 &gt; are each independently optionally substituted phenyl or terphenyl, R3 is substituted or unsubstituted pyridyl or quinoline, When R3 is pyridyl, then R2 is terphenyl. delete The method according to claim 1, When the phenyl or terphenyl is substituted, the substituent is any one selected from the group consisting of methyl, ethyl, isopropyl, tertbutyl, cyclohexyl, methoxy, ethoxy, fluoride and cyano. delete The method according to claim 1, Wherein when the pyridyl or quinoline is substituted, the substituent is a methyl group. delete delete In an organic electroluminescent device comprising an anode, a hole injecting layer, a hole transporting layer, a light emitting layer, an electron transporting layer, an electron injecting layer and a cathode, Wherein the electron transporting layer comprises the electron transporting compound of any one of claims 1, 3 and 5.

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