KR20200051468A - Organic compound and organic electroluminescent device comprising the same - Google Patents

Abstract

The present invention provides an organic electroluminescent device having improved driving voltage, efficiency, and lifespan. The organic electroluminescent device includes: an anode; a cathode; and at least one organic film disposed between the anode and the cathode, wherein the one organic film includes a light emitting layer and a compound which is disposed between the anode and the light emitting layer and represented by the following chemical formula 1.

Description

Organic compounds and organic electroluminescent devices comprising the same {ORGANIC COMPOUND AND ORGANIC ELECTROLUMINESCENT DEVICE COMPRISING THE SAME}

The present invention relates to a novel organic compound and an organic electroluminescent device comprising the same.

Recently, with the enlargement of the display device, interest in a flat display device having little space is increasing. As one of such flat panel display devices, the technology of organic light emitting display devices including organic light emitting diodes (OLEDs) is rapidly developing.

The organic light emitting diode is a device that emits exciton energy as light after electrons and holes are paired to form excitons (excitons) when a charge is injected into the light emitting layer formed between the first electrode and the second electrode. Organic light-emitting diodes have the advantage of being capable of low-voltage driving, relatively low power consumption, excellent color, and flexible application as they are applicable to conventional display technologies.

An object of the present invention is to provide an organic light emitting device having improved driving voltage, efficiency and life.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention not mentioned can be understood by the following description, and will be more clearly understood by embodiments of the present invention. In addition, it will be readily appreciated that the objects and advantages of the present invention can be realized by means of the appended claims and combinations thereof.

The organic light emitting device according to the present invention is an organic light emitting device including an anode, a cathode, and at least one or more organic films between the anode and the cathode, wherein the organic film includes a light emitting layer, and the following formula between the anode and the light emitting layer It includes an organic film containing a compound represented by 1.

[Formula 1]

In Chemical Formula 1,

L ₁ and L ₂ are each independently a substituted or unsubstituted C ₆ -C ₃₀ arylene group, a substituted or unsubstituted C ₃ -C ₃₀ heteroarylene group, a substituted or unsubstituted C ₁ -C ₂₀ alkyl A alkylene group, a substituted or unsubstituted C ₃ -C ₂₀ cycloalkylene group, a substituted or unsubstituted C ₁ -C ₂₀ alkenylene group, a substituted or unsubstituted C ₃ -C ₂₀ cycloalkenylene group, a substituted or Unsubstituted C ₁ -C ₂₀ heteroalkylene group, substituted or unsubstituted C ₃ -C ₂₀ heterocycloalkylene group, substituted or unsubstituted C ₁ -C ₂₀ heteroalkenylene group, and substituted or unsubstituted Selected from the group consisting of C ₃ -C ₂₀ heterocycloalkenylene groups, Ar ₁ is a substituted or unsubstituted C ₇ -C ₃₀ arylene group or heteroarylene group, and Ar ₂ is a substituted or unsubstituted C _8- C ₃₀ is a condensed polycyclic group, and R ₁ to R ₄ are each independently the same as or different from each other, and hydrogen, deuterium, and substitution. Or an unsubstituted C ₁ -C ₂₀ alkyl group, an unsubstituted C ₃ -C ₃₀ cycloalkyl group, a substituted or unsubstituted C ₁ -C ₂₀ alkenyl group, a substituted or unsubstituted C ₁ -C ₂₀ alky. Nyl group, substituted or unsubstituted C ₁ -C ₂₀ heteroalkyl group, substituted or unsubstituted C ₃ -C ₂₀ aralkyl group, substituted or unsubstituted C ₆ -C ₃₀ aryl group, substituted or unsubstituted C ₃ -C ₃₀ heteroaryl group, and a substituted or unsubstituted C ₃ -C ₂₀ heteroaralkyl group is selected from the group consisting of, k, l, m, and n are each independently an integer of 0 to 4.

The driving voltage, efficiency and life of the organic light emitting device according to the present invention are improved.

In addition to the above-described effects, the concrete effects of the present invention will be described together while describing the specific matters for carrying out the invention.

As used herein, 'unsubstituted' or 'unsubstituted' means that a hydrogen atom is substituted, and in this case, the hydrogen atom includes light hydrogen, deuterium, and tritium.

In the present specification, a substituent in 'substituted' may include, for example, deuterium, an alkyl group having 1 to 20 carbon atoms unsubstituted or substituted with halogen, an alkoxy group having 1 to 20 carbon atoms unsubstituted or substituted with halogen, halogen, or cyano group. , Carboxyl group, carbonyl group, amine group, alkyl amine group having 1 to 20 carbon atoms, nitro group, alkyl silyl group having 1 to 20 carbon atoms, alkoxy silyl group having 1 to 20 carbon atoms, cycloalkyl silyl group having 3 to 30 carbon atoms, carbon number 5 It may be one selected from the group consisting of aryl silyl groups of 30 to 30, aryl groups of 5 to 30 carbon atoms, aryl amine groups of 5 to 20 carbon atoms, heteroaryl groups of 4 to 30 carbon atoms, and combinations thereof. It is not limited.

As used herein, 'alkyl' refers to all alkyl, including straight-chain alkyl and branched-chain alkyl.

In the present specification, 'heteroaromatic ring', 'heterocycloalkylene group', 'heteroarylene group', 'heteroaryl alkylene group', 'hetero oxyarylene group', 'hetero cycloalkyl group', 'heteroaryl group', 'heteroaryl group' The term 'hetero' as used in 'aryl alkyl group', 'hetero oxy aryl group', 'heteroaryl amine group' and the like, is one or more of the carbon atoms constituting these aromatic (alimatic) or alicyclic (alicyclic) ring, for example It means that 1 to 5 carbon atoms are substituted with one or more hetero atoms selected from the group consisting of N, O, S and combinations thereof.

In the present specification, "a combination of these" in the definition of a substituent means that two or more substituents are bonded to a linking group, or two or more substituents are condensed to bond, unless otherwise specified.

Hereinafter, an organic electroluminescent device according to some embodiments of the present invention will be described.

In one embodiment of the present invention, an anode, a cathode, and an organic electroluminescent device comprising at least one organic film between the anode and the cathode, the organic film includes a light emitting layer, the following formula 1 between the anode and the light emitting layer It provides an organic electroluminescent device comprising an organic film containing a compound represented by.

[Formula 1]

In Chemical Formula 1,

L ₁ and L ₂ are each independently a substituted or unsubstituted C ₆ -C ₃₀ arylene group, a substituted or unsubstituted C ₃ -C ₃₀ heteroarylene group, a substituted or unsubstituted C ₁ -C ₂₀ alkyl A alkylene group, a substituted or unsubstituted C ₃ -C ₂₀ cycloalkylene group, a substituted or unsubstituted C ₁ -C ₂₀ alkenylene group, a substituted or unsubstituted C ₃ -C ₂₀ cycloalkenylene group, a substituted or Unsubstituted C ₁ -C ₂₀ heteroalkylene group, substituted or unsubstituted C ₃ -C ₂₀ heterocycloalkylene group, substituted or unsubstituted C ₁ -C ₂₀ heteroalkenylene group, and substituted or unsubstituted Selected from the group consisting of C ₃ -C ₂₀ heterocycloalkenylene groups, Ar ₁ is a substituted or unsubstituted C ₇ -C ₃₀ arylene group or heteroarylene group, and Ar ₂ is a substituted or unsubstituted C _8- C ₃₀ is a condensed polycyclic group, and R ₁ to R ₄ are each independently the same as or different from each other, and hydrogen, deuterium, and substitution. Or an unsubstituted C ₁ -C ₂₀ alkyl group, an unsubstituted C ₃ -C ₃₀ cycloalkyl group, a substituted or unsubstituted C ₁ -C ₂₀ alkenyl group, a substituted or unsubstituted C ₁ -C ₂₀ alky. Nyl group, substituted or unsubstituted C ₁ -C ₂₀ heteroalkyl group, substituted or unsubstituted C ₃ -C ₂₀ aralkyl group, substituted or unsubstituted C ₆ -C ₃₀ aryl group, substituted or unsubstituted C ₃ -C ₃₀ heteroaryl group, and a substituted or unsubstituted C ₃ -C ₂₀ heteroaralkyl group is selected from the group consisting of, k, l, m, and n are each independently an integer of 0 to 4.

Preferably, in the compound represented by Chemical Formula 1, Ar ₁ is a substituted or unsubstituted C ₇ -C ₁₅ arylene group or heteroarylene group, for example, biphenyl, naphthyl, phenanthrene, dibenzofuran, di Benzothiophene, or fluorene.

In addition, preferably, in the compound represented by Chemical Formula 1, L ₁ and L ₂ may be substituted or unsubstituted phenylene.

Specifically, the compound represented by Formula 1 may be represented by the following compounds 1 to 166, which is not limited.

The organic electroluminescent device includes a compound represented by Chemical Formula 1, as described above.

Specifically, the organic light emitting device includes a first electrode, a second electrode, and an organic material layer formed between the first electrode and the second electrode, and the organic material layer includes a hole transport layer and a hole between the first electrode and the light emitting layer. It includes a transport auxiliary layer, the hole transport auxiliary layer may include a compound represented by the formula (1).

The hole transport auxiliary layer plays a role of reducing the accumulation of holes at the interface of the light emitting layer due to the difference in the HOMO level between the hole transport layer and the light emitting layer. To this end, the difference in HOMO energy from the light emitting layer is smaller than the difference in HOMO energy from the hole injection layer. It is preferred. In addition, in order to minimize the leakage of electrons from the light emitting layer to the hole transport layer, it must have a higher LUMO energy level than the light emitting layer.

In one example, the compound that can be used in the hole transport auxiliary layer is as follows.

[Compound A]

       [Compound B]

       [Compound C]

        [Compound D]

        [Compound 7]

The energy levels of compounds A, B, and 7 among the compounds are calculated and are shown in Table 1 below.

HOMO (calculation) LUMO (calculation) Compound A -5.00 -0.88 Compound B -5.02 -1.14 Compound 7 -5.08 -1.14

     As can be seen in Table 1, 9-carbazole is a compound 7, the 9-carbazole is meta-positioned in the meta position compared to the para-bonded position, the HOMO energy level shows a lower value, and accordingly It can be seen that the difference in the HOMO level from the light emitting layer is small. That is, the compound in which 9-carbazole is bonded to the meta position has reduced hole accumulation at the interface of the light emitting layer, so that the efficiency and lifetime characteristics of the organic light emitting device can be improved.

In addition, the electron density distribution of HOMO and LUMO states of the compounds is shown in Table 2 below.

rescue HOMO
Electron density distribution LUMO
Electron density distribution Compound A

Compound B

Compound C

Compound D

Compound 7

As can be seen from Table 2, it can be seen that the compound A having only biphenyl attached to the amine and the compound D having the naphthyl directly attached to the amine overlap the electron density positions of the HOMO state and the LUMO state. In contrast, compounds B, C, and 7 in which naphthyl or phenanthrene is bonded to an amine through a phenyl linker are distributed around naphthyl or phenanthrene (condensed compound) with an electron density of LUMO at a distance from the amine. It can be seen that the electron density of the HOMO state and the LUMO state is distributed at different positions. Due to this, compounds B, C, and 7 have electrons from the light-emitting layer confined to naphthyl or phenanthrene, and exhibit different electron densities from the hole-transporting layer, which affects hole-transporting less, and exhibits stable bonding, resulting in the lifetime of the organic light emitting device. The properties can be improved.

That is, in the compound represented by Chemical Formula 1 according to the present invention, 9-carbazole is bonded to the meta position, and hole accumulation at the interface of the light emitting layer is reduced, so that efficiency and lifespan characteristics of the organic light emitting device can be improved.

Hereinafter, examples and comparative examples of the present invention will be described. The following examples are only examples of the present invention, and the present invention is not limited to the following examples.

(Example)

Hereinafter, the compounds used in Examples and Comparative Examples were synthesized as follows.

Synthetic example  1: Preparation of compound 1

[Scheme 1]

3 '-(9H-carbazol-9-yl) -N- (4- (naphthalen-1-yl) phenyl)-[1,1'-biphenyl] -4-amine ( 8.0 g, 14.91 mmol) and 4-bromo-1,1 ': 4', 1 ''-terphenyl (5.07 g, 16.40 mmol) were mixed, sodium tert butoxide (2.62 g, 27.27 mmol), Pd ₂ (dba) ₃ (0.25 g, 0.27 mmol), 2-dicyclohexylphosphino-2 ', 6'-dimethoxybiphenyl (0.22 g, 0.54 mmol) is added, 100 mL of toluene is added and stirred to reflux Ordered.

After completion of the reaction, a toluene layer was extracted using 50 mL of water. The extracted solution was treated with MgSO ₄ to remove residual moisture, concentrated under reduced pressure, and purified using a column chromatography method. Then, recrystallization with dichloromethane / methanol gave 5.96 g of compound 1 in 52.3% yield.

Synthetic example  2: Preparation of compound 7

[Scheme 2]

3 '-(9H-carbazole-9-yl)-[1,1'-biphenyl] -4-amine (8.0 g, 14.91 mmol) and 1- (4-bromophenyl) naphthalene (9.29 g, 32.79 mmol) was used in the same manner as in Synthesis Example 1 to obtain 6.03 g of Compound 7 in a yield of 54.8%.

Synthetic example  3: Preparation of compound 13

[Scheme 3]

3 '-(9H-carbazol-9-yl) -N- (4- (naphthalen-1-yl) phenyl)-[1,1'-biphenyl] -4-amine (8.0 g, 14.91 mmol) 5.47 g of Compound 13 was obtained in a yield of 49.7% using the same method as in Synthesis Example 1, except that 2- (4-bromophenyl) naphthalene (4.64 g, 16.40 mmol) was used.

Synthetic example  4: Preparation of compound 31

[Reaction Scheme 4]

Compound 5.2 5.2 g using the same method as in Synthesis Example 1, except that 1- (4-bromophenyl) naphthalene (4.25 g, 15.00 mmol) was used instead of 4-bromo-1,1′-biphenyl. Was obtained in 48.3% yield.

Synthetic example  5: Preparation of compound 32

       [Scheme 5]

3 '-(9H-carbazole-9-yl) -N- (3- (phenanthrene-9-yl) phenyl)-[1,1'-biphenyl] -4-amine (8.0 g, 13.63 mmol) mmol) and 1- (4-bromophenyl) naphthalene (4.25 g, 15.00 mmol) were obtained in the same manner as in Synthesis Example 1 to obtain 5.1 g of Compound 32 in a yield of 47.4%.

Synthetic example  6: Preparation of compound 66

[Scheme 6]

3 '-(9H-carbazol-9-yl) -N- (4- (naphthalen-1-yl) phenyl)-[1,1'-biphenyl] -4-amine (8.0 g, 14.91 mmol) 6.66 g of Compound 66 was obtained in 52.6% yield using the same method as in Synthesis Example 1, except that 4- (4-bromophenyl) dibenzofuran (5.30 g, 16.40 mmol) was used.

Synthetic example  7: Preparation of compound 91

[Scheme 7]

3 '-(9H-carbazole-9-yl)-[1,1'-biphenyl] -4-amine (8.0 g, 14.91 mmol) and 2- (4-bromophenyl) naphthalene (9.29 g, 32.79 mmol), except that 6.12 g of Compound 91 was obtained in a 55.6% yield using the same method as in Synthesis Example 1.

Synthetic example  8: Preparation of compound 109

[Scheme 8]

5.5 g of compound 109 was prepared using the same method as in Synthesis Example 1, except that 2- (4-bromophenyl) naphthalene (4.25 g, 15.00 mmol) was used instead of 4-bromo-1,1'-biphenyl. Was obtained in 51.1% yield.

[Example 1: Preparation of organic electroluminescent device]

An anode was formed of ITO on the substrate on which the reflective layer was formed, and the surface was treated with N ₂ plasma or UV-ozone. HAT-CN was deposited on the hole injection layer (HIL) to a thickness of 10 nm. Subsequently, N4, N4, N4 ', N4'-tetra ([1,1'-biphenyl] -4-yl)-[1,1'-biphenyl] -4,4'-diamine was deposited to a thickness of 110 nm. A hole transport layer (HTL) was formed.

9,10-Bis (2-naphthyl) capable of forming a blue EML as an emission layer (EML) on the hole transport auxiliary layer by forming a hole transport auxiliary layer by vacuum-depositing Compound 1 on the hole transport layer to a thickness of 15 nm. ) While depositing 25 nm of anthraces (ADN), dopants were doped with N1, N1, N6, N6-tetrakis (4- (1-silyl) phenyl) pyrene-1,6-diamine about 3 wt%.

Anthracene derivative and LiQ were mixed at a mass ratio of 1: 1 to deposit an electron transport layer (ETL) with a thickness of 30 nm, and LiQ was deposited with an electron injection layer (EIL) to a thickness of 1 nm. Then, a mixture of magnesium and silver (Ag) 9: 1 as a negative electrode was deposited to a thickness of 15 nm, and N4, N4'-bis [4- [bis () as a capping layer on the negative electrode. 3-methylphenyl) amino] phenyl] -N4, N4'-diphenyl- [1,1'-biphenyl] -4,4'-diamine (DNTPD) was deposited to a thickness of 60 nm. On top of that, an organic light emitting device was manufactured by bonding a seal cap containing a moisture absorbent with a UV curable adhesive to protect the organic light emitting device from O ₂ or moisture in the air.

[Examples 2 to 8]

Organic in the same manner as in Example 1, except that Compound 7, 13, 31, 32, 66, 91 and 109 synthesized in Synthesis Examples 2 to 8 were used instead of the hole transport auxiliary layer Compound 1 in Example 1. An electroluminescent device was manufactured.

[Comparative Examples 1 to 5]

An organic electroluminescent device was manufactured in the same manner as in Example 1, except that Compound A to Compound E were used instead of Compound 1 as the hole transport auxiliary layer in Example 1.

[Compound A]

[Compound B]

[Compound C]

[Compound D]

[Compound E]

[Experimental Example 1: Device performance analysis]

Analyzes all-optical properties of the device in the condition of a constant current 10mA / cm ² for the organic electroluminescent device manufactured in Examples and Comparative Examples above and measuring the lifetime in the drive condition of 20mA / cm ² and the results are shown in Table 1 Shown. As shown in the results of Table 3, it can be seen that the organic electroluminescent devices containing the compounds of Examples 1 to 8 are improved in driving voltage, efficiency and lifespan compared to the organic electroluminescent devices containing the compounds of Comparative Examples 1 to 5. have.

Hole transport auxiliary layer V Cd / A lm / W CIEx CIEy T95 (hrs) Example 1 Compound 1 3.97 6.5 5.1 0.141 0.047 300 Example 2 Compound 7 3.93 6 4.8 0.139 0.051 320 Example 3 Compound 13 3.94 6.6 5.3 0.138 0.05 315 Example 4 Compound 31 4.12 6.2 4.7 0.139 0.052 310 Example 5 Compound 32 3.9 6 4.8 0.139 0.051 280 Example 6 Compound 66 3.92 5.8 4.6 0.14 0.045 240 Example 7 Compound 91 3.9 5.6 4.5 0.141 0.044 290 Example 8 Compound 109 3.99 5.9 4.6 0.144 0.042 210 Comparative Example 1 Compound A 3.99 5.9 4.6 0.144 0.044 120 Comparative Example 2 Compound B 3.9 5.8 4.7 0.141 0.049 135 Comparative Example 3 Compound C 4.1 6.0 4.6 0.142 0.046 150 Comparative Example 4 Compound D 3.99 5.9 4.6 0.139 0.051 115 Comparative Example 5 Compound E 4.11 5.6 4.3 0.142 0.047 120

As described above, the present invention is not limited by the embodiments disclosed herein, and it is obvious that various modifications can be made by those skilled in the art within the scope of the technical idea of the present invention. In addition, although the operation and effect according to the configuration of the present invention has not been explicitly described while describing the embodiments of the present invention, it is natural that the predictable effect by the configuration should also be recognized.

Claims (6)

An organic electroluminescent device comprising an anode, a cathode, and at least one organic layer between the anode and the cathode,
The organic layer includes a light emitting layer,
An organic electroluminescent device comprising an organic film comprising a compound represented by Formula 1 below between the anode and the light emitting layer:
[Formula 1]

In Chemical Formula 1,
L ₁ and L ₂ are each independently a substituted or unsubstituted C ₆ -C ₃₀ arylene group, a substituted or unsubstituted C ₃ -C ₃₀ heteroarylene group, a substituted or unsubstituted C ₁ -C ₂₀ alkyl A alkylene group, a substituted or unsubstituted C ₃ -C ₂₀ cycloalkylene group, a substituted or unsubstituted C ₁ -C ₂₀ alkenylene group, a substituted or unsubstituted C ₃ -C ₂₀ cycloalkenylene group, a substituted or Unsubstituted C ₁ -C ₂₀ heteroalkylene group, substituted or unsubstituted C ₃ -C ₂₀ heterocycloalkylene group, substituted or unsubstituted C ₁ -C ₂₀ heteroalkenylene group, and substituted or unsubstituted C ₃ -C _{20 It} is selected from the group consisting of a heterocycloalkenylene group,
Ar ₁ is a substituted or unsubstituted C ₇ -C ₃₀ arylene group or heteroarylene group,
Ar ₂ is a substituted or unsubstituted C ₈ -C ₃₀ condensed polycyclic group,
R ₁ to R ₄ are each independently the same or different from each other, and hydrogen, deuterium, a substituted or unsubstituted C ₁ -C ₂₀ alkyl group, an unsubstituted C ₃ -C ₃₀ cycloalkyl group, a substituted or unsubstituted C, ₁ -C ₂₀ alkenyl group, substituted or unsubstituted C ₁ -C ₂₀ alkynyl group, substituted or unsubstituted C ₁ -C ₂₀ heteroalkyl group, substituted or unsubstituted C ₃ -C ₂₀ aralkyl group, Selected from the group consisting of a substituted or unsubstituted C ₆ -C ₃₀ aryl group, a substituted or unsubstituted C ₃ -C ₃₀ heteroaryl group, and a substituted or unsubstituted C ₃ -C ₂₀ heteroaralkyl group; ,
k, l, m, and n are each independently an integer from 0 to 4.
According to claim 1,
The L ₁ and L ₂ are substituted or unsubstituted phenylene organic electroluminescent device.
According to claim 1,
Ar ₁ Is a substituted or unsubstituted C ₇ -C ₁₅ aryl group
Organic electroluminescent device.
According to claim 1,
Ar ₂ is substituted or unsubstituted naphthyl.
Organic electroluminescent device.
According to claim 1,
The organic layer includes a hole transport auxiliary layer containing the compound represented by Formula 1
Organic electroluminescent device.
According to claim 1,
The organic layer includes at least one layer selected from the group consisting of a hole injection layer, a hole transport layer, a hole transport auxiliary layer, a light emitting layer, an electron transport auxiliary layer, an electron transport layer and an electron injection layer
Organic electroluminescent device.