KR20160126262A

KR20160126262A - Silole dirivative for hole transporting material and organic light emitting diodes using the same

Info

Publication number: KR20160126262A
Application number: KR1020150057129A
Authority: KR
Inventors: 채규윤; 김보미; 강태진; 백오현; 고혜민
Original assignee: 원광대학교산학협력단
Priority date: 2015-04-23
Filing date: 2015-04-23
Publication date: 2016-11-02
Also published as: KR101798143B1

Abstract

The present invention relates to a novel silane derivative for a hole transport material and an organic electroluminescent device using the same. More particularly, the present invention relates to a silanol derivative having a carbazole or triphenylamine derivative end- And exhibits excellent thermal stability and photophysical properties from an organic light emitting device to a hole transporting material, and to an organic electroluminescent device using the same.

Description

Technical Field [0001] The present invention relates to a silane derivative for a hole transporting material and an organic electroluminescent device using the same,

The present invention relates to a novel silane derivative for a hole transport material and an organic electroluminescent device using the same. More particularly, the present invention relates to an organic electroluminescent device having a structure in which a carbazole or a triphenylamine derivative is end- A device for the hole transport material, and an organic electroluminescent device using the same.

BACKGROUND OF THE INVENTION [0002] Organic light-emitting diodes (OLEDs) have recently received increased interest due to their advantages such as low power consumption, high contrast and brightness, easy fabrication, and the use of a wide range of emission colors in flat panel displays and solid state lighting . However, improving the efficiency and durability of OLED device performance is still an important challenging issue. In particular, the thermal instability of the organic material in the hole transport layer is considered to be the main cause of the degradation of the stability of the device at high temperature operation. For example, a commonly used hole transported material (HTM) such as N, N'-di (1-naphthyl) -N, N'-diphenyl- (1,1'- 4,4'-diamine (NPB) has a somewhat lower glass transition temperature (Tg) of 95 ° C.

Accordingly, other synthetic approaches based on non-planar molecular structures have been developed to produce high Tg values. Of these, star-shaped molecules, in which several linear arms are joined together in a central core, have received considerable attention due to the bulk structure and the increase in the number of conformers. In addition, star-like molecules have relatively good film-forming properties and high luminous properties because they are composed of multi-conjugated branches elongated in different directions.

On the other hand, silole is a substance which is attracted worldwide attention due to its electrical properties due to the specific structure of the molecule as a silicon analogue. It is an efficient material for electron transport because it has a low LUMO due to the interaction between semi-bonding sigma orbital of silicon and semi-bonding fi bond of butadiene.

It is also recognized that triarylamine and carbazole can be excellent moieties for the development of HTM due to their strong electron-donating properties.

Korean Patent No. 10-1002733

In order to solve the problems of the prior art as described above, the present invention relates to a silanol derivative for a hole transport material of organic electroluminescent device having a structure in which a carbazole or triphenylamine derivative is end- And an object of the present invention is to provide an electroluminescent element.

It is another object of the present invention to provide a silane derivative for an organic electroluminescent device hole transport material and an organic electroluminescent device using the same, which is suitable for application to an organic electroluminescent device requiring high temperature and long lifetime.

In order to accomplish the above object, the present invention provides a celron derivative for a hole transport material of an organic electroluminescent device represented by the following Formula 1:

[Chemical Formula 1]

In Formula 1,

Each R is independently H, halogen, hydroxy, C1-20 alkoxy, C6-30 aryl, C1-100 alkylamine or C6-100 arylamine,

,

or

to be.

In particular, the cilon derivative represented by the formula (1) is preferably a compound represented by the following formula (1a), (1b) or (1c).

[Formula 1a]

[Chemical Formula 1b]

[Chemical Formula 1c]

The present invention also relates to a method for preparing a hole for an organic electroluminescence device represented by the above Chemical Formula 1, characterized in that a residue of any one selected from among carbazole, triphenylamine and triphenylamine derivatives is subjected to a Negishi coupling reaction A method for producing a transport material is provided.

Specifically, the process comprises reacting a compound of formula (2) and a compound of formula (3), (4) or (5) with a Pd catalyst under a solvent. At this time, the reaction is preferably carried out with stirring at 70 to 90 ° C for 10 to 12 hours.

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

In the formulas (3) to (5)

L are each independently -I, -Cl, -Br, -F, -OSO 3 H, -SSO 3 H, -OCO-CH 3, -OPO 3 H 2, -OCO-C 6 H 5, -OSO 2 -C ₁ -C ₄ alkyl or a leaving group of OSO ₂ N (C ₁ -C ₄ alkyl).

The present invention also provides an organic electroluminescent device including the hole transporting material represented by Formula 1 in a hole transporting layer.

The novel hole transporting material for an organic electroluminescence device according to the present invention has a structure in which a carbazole or triphenylamine derivative is capped at the end of a silole core and has excellent color purity and optical efficiency, Stability and photophysical properties and is suitable for application to organic electroluminescent devices requiring high temperature and long lifetime.

Hereinafter, the present invention will be described in detail.

The inventors of the present invention discovered that a silole derivative prepared by capping a carbazole or a triarylamine derivative on a silole core has excellent color purity and optical efficiency and is a hole transport material in an organic light- And exhibits excellent thermal stability and photophysical properties, thus completing the present invention.

Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Repeated descriptions of the same technical constitution and operation as those of the conventional art will be omitted.

The present invention provides a silole derivative for a hole transport material of an organic electroluminescent device represented by the following general formula (1).

[Chemical Formula 1]

In Formula 1,

,

or

to be.

Specifically, the hole transporting material for an organic electroluminescence device represented by Formula 1 may be a compound represented by Formula 1a, 1b or 1c.

[Formula 1a]

[Chemical Formula 1b]

[Chemical Formula 1c]

The silole derivative for the hole transport material of the organic electroluminescent device represented by the above-mentioned formula (1) can be prepared by reacting a silanol core with a carbazole, triphenylamine, triphenylamine derivative or the like The residue has a terminally capped structure.

Specifically, the residue of the carbazole, triphenylamine, triphenylamine derivative or the like is

,

or

.

The silole derivative for a hole transport material of the present invention represented by Formula 1 of the present invention as described above can be obtained by reacting a silane derivative with any one selected from carbazole, triphenylamine, and triphenylamine derivatives as Negishi, Coupling reaction.

Specifically, the silole derivative may be prepared by subjecting a compound of the following formula (2) and a compound of the following formula (3), (4) or (5)

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

In the formulas (3) to (5)

The ness reaction can be carried out with stirring the Pd catalyst at room temperature under a solvent. More specifically, the compound of Formula 2 and the compound of Formula 3, Formula 4 or Formula 5 are mixed with a Pd catalyst in a solvent and stirred at 70 to 90 ° C for 10 to 12 hours to obtain a silole derivative of Formula 1 .

Examples of the solvent include distilled water, tetrachloroethane, dimethylacetamide, triethylamine, dimethylformamide, chloroform, methylene chloride, ethyl acetate, methanol, hexane, acetonitrile, toluene, benzene, carbon tetrachloride, pentane, acetone, dimethyl Sulfoxide, tetrahydrofuran, dimethylformaldehyde, and the like, but not limited thereto.

In addition, the Pd catalyst is _{PD (PPH 3) 2 Cl 2} , Pd (ll) acetate, Pd (OAc) 2, PdCl 2 Pd 2 (dab) r, Pd (PPh 3) 4 and the like may be used, in particular PD (PPH ₃ ) ₂ Cl ₂ is preferably used.

Specifically, the novel silanol derivative for a hole transport material of the present invention as described above can be prepared according to the following Reaction Schemes 1 to 3.

[Reaction Scheme 1]

[Reaction Scheme 2]

[Reaction Scheme 3]

The present invention also provides an organic electroluminescent device including the hole transporting material represented by Formula 1 of the present invention as described above as a hole transporting layer. The hole transport material represented by Formula 1 may be used in a hole transport layer of an organic electroluminescent device to improve current efficiency, power efficiency, and lifetime characteristics.

The organic electroluminescent device includes a first electrode, a second electrode, and at least one organic material layer interposed between the first electrode and the second electrode. The organic material layer includes the electron transporting material represented by Formula 1 of the present invention Lt; / RTI > electron transport layer.

The organic material layer may include a hole injection layer, a hole transport layer, a light emitting layer, and an electron injection layer.

Specifically, the organic electroluminescent device is formed by coating an anode material as a first electrode on an upper portion of a lower substrate.

The substrate may be a glass, an organic substrate, or a transparent plastic substrate having excellent transparency, surface smoothness, ease of handling, and waterproofness, which is used in a conventional organic electroluminescent device.

The anode material used as the first electrode is a metal film that is a reflective film in the case of a top emission structure, and a transparent and highly conductive indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide ₂ ), zinc oxide (ZnO) or the like is used. Thereafter, an insulating film (PDL) defining a pixel region is formed.

After forming an insulating film, a hole injecting layer and / or a hole transporting layer are stacked over the entire substrate with an organic film.

The hole injection layer material may be selectively deposited on the anode by vacuum thermal deposition or spin coating to form a hole injection layer (HIL). The hole injection layer material is not particularly limited, and copper phthalocyanine (CuPc) or Starburst type amines such as TCTA, m-MTDATA, and IDE406 (Idemitsu Materials) can be used.

A hole transport layer (HTL) is formed on the hole injection layer by vacuum thermal deposition or spin coating to form a hole transport layer (HTL). At this time, it is more preferable that the hole transporting layer is formed to have a thickness of about 50 to 1,500 angstroms in terms of hole transporting characteristics and driving voltage characteristics.

Then, a red light emitting material, a green light emitting material, and a blue light emitting material are patterned in the R and G regions of the pixel region to form a light emitting layer (EML) as a pixel region. The light emitting layer forming method is not particularly limited, but a vacuum deposition method, an ink jet printing method, a laser transfer method, and a photolithography method may be used.

An electron injection layer (EIL) may be selectively deposited on the electron transport layer. The electron injection layer material is not particularly limited, and materials such as LiF, NaCl, CsF, Li2O, BaO, and Liq can be used.

Subsequently, a metal for a cathode, which is a second electrode, is deposited on the electron injection layer by vacuum thermal deposition, and the cathode, which is the second electrode, is coated over the entire surface of the substrate and sealed to complete the organic electroluminescent device. The cathode metal may be Li, Mg, Al, Al-Li, Ca, Mg-In, Mg-Ag, ) May be used.

Hereinafter, the present invention will be described in more detail with reference to examples. These embodiments are for purposes of illustration only and are not intended to limit the scope of protection of the present invention.

The reagents and solvents used in the following examples were purchased from Aldrich and TCI Chem., And used without purification.

In addition, ¹ H and ¹³ C NMR spectra were measured using a JEON JNM-ECP FT-NMR spectrometer operating at 500 MHz and 125 MHz, respectively. The UV-vis absorption spectrum was measured using a Scinco S-3100 spectrophotometer, and the photoluminescence (PL) spectrum was measured using a CARY Eclipse Varian fluorescence spectrophotometer. The HOMO value was calculated from the oxidation potential and the LUMO value was calculated based on the lowest energy absorption limit of the HOMO value and the UV-vis absorption spectrum. Thermogravimetric analysis (TGA) was performed on a thermal analysis system TG 209F1 (NET-ZSCH) at a heating rate of 20 ° C min ^-1 .

Example 1. Synthesis of 9- (4- (5- (4- (9H-carbazol-9-yl) phenyl) -1,1,3,4-tetraphenyl- Preparation of 9H-carbazole (Formula 1a)

2.6 g (2.08 mmol) of naphthalene was dissolved in 10 mL of THF in a one-neck round flask. In another reaction vessel, 0.07 g (1.04 mmol) of lithium was dissolved in 5 mL of THF and transferred to a one-neck flask in which naphthalene was dissolved by using a syringe. At this time, an argon gas balloon was inserted to protect the reaction vessel. Then, the reaction was allowed to proceed at 0 캜 for 12 hours until room temperature was reached to synthesize deep blue-green LiNp. In another reaction vessel, 1 g (2.60 mmol) of diphenylbis (phenylethylnyl) -silane was dissolved in 10 mL of THF, and this solution was treated with a syringe to remove one -nech flask and stirred for 3 hours at 0 < 0 > C until room temperature. Then, to a new round flask was added 2.60 g of dichloro (N, N ', N'-tetramethyl-ethylenediamine) zinc (N, N', N'- The temperature of the reaction vessel was dropped to -10 ° C using an ICE bath, and the prepared zinc solution was added thereto for 1 hour to give a pale yellowish silane derivative (Formula 2) Prepared.

The argon gas balloon of the reaction vessel containing the silane derivative was removed, and 1 g (3.1 mmol) of 9- (4-bromophenyl) -9H-carbazole, ) And 0.1% mol of PD (PPH ₃ ) ₂ Cl ₂ as a palladium catalyst. THF was added as a solvent and reacted at 80 ° C for 12 hours under reflux. The resulting product solution was extracted with MC (methylene chloride) solution, and the organic layer was separated and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using MC: Hex = 4: 1 as an eluent to obtain 9- (4- (5- (4- (9H-carbazol-9-yl) phenyl) -1,1,3,4-tetraphenyl-H-silol-2-yl) phenyl) -9H-carbazole.

¹ H NMR (500 MHz, CDCl ₃ )? 7.21-7.28 (m, 15H), 7.33 (m, 3H), 7.45 (m, 4H), 7.58-7.67 ), 8.02 (m, 5H);

¹³ C NMR (125 MHz, CDCl ₃ )? 111.1, 118.0, 119.0, 120.1, 121.5, 1222.2, 126.4, 128.4, 130.1, 132.6, 138.0, 139.7, 142.9.

Example 2. Synthesis of 9-phenyl-3- (1,1,3,4-tetraphenyl) -5- (9-phenyl-9H-carbazol-6-yl) -Carbazole (Formula Ib)

The argon gas balloon of the reaction vessel containing the silane derivative prepared in Example 1 was removed and 1 g (3.1 mmol) of 3-bromo-9-phenyl-9H-carbazole (Formula 3) ₃ ) ₂ Cl ₂ 0.1% mol was added, THF was added as a solvent, and the mixture was reacted at 80 ° C for 12 hours while refluxing. The obtained product solution was extracted with MC (methylene chloride) solution, and the organic layer was separated and concentrated under reduced pressure to give 9-phenyl-3- (1 (9-phenyl-9H-carbazol-6-yl) -lH-silol-2- yl) -9H-carbazole (Formula Ib).

^{1 H NMR (500 MHz, CDCl} 3) δ 6.86 (m, 5H), 7.01-7.05 (m, 4H), 7.22-7.41 (m, 15H), 7.53 (m, 5H), 7.63-7.69 (m, 8H ), 7.75 (m, 4H), 8.03 (m, 6H), 8.16-8.20 (m, 5H);

^{13 C NMR (125 MHz, CDCl} 3) δ 111.6, 118.0, 120.1, 121.6, 126.4, 126.9, 128.4, 129.4, 130.1, 132.6, 138.0, 143.7, 145.0.

Example 3. Synthesis of N- (3- (5- (4- (diphenolamino) phenyl) -1,1,3,4-tetraphenyl 1H-silol- 1c) Manufacturing

The argon gas balloon of the reaction vessel containing the silane derivative prepared in Example 1 was removed, and N- (4-bromophenyl) -N-phenylbenzenamine 4) and 0.1% mol of PD (PPH ₃ ) ₂ Cl ₂ as a palladium catalyst, THF was added as a solvent, and the mixture was reacted at 80 ° C for 12 hours under reflux. The resulting product solution was extracted with MC (methylene chloride) solution, and the organic layer was separated and concentrated under reduced pressure to give N- (3- (5- Yl) phenyl-N-phenylbenzene amine (formula (Ic)).

^{1 H NMR (500 MHz, CDCl} 3) δ 6.67-6.76 (m, 8H), 6.69-7.06 (m, 10H), 7.25 (m, 9H), 7.33 (m, 3H), 7.53 (m, 4H), 7.63 (m, 4H), 7.73-7.77 (m, 3H), 8.01 (m, 3H), 8.16-8.19 (m, 4H);

¹³ C NMR (125 MHz, CDCl ₃ )? 118.0, 122.7, 126.4, 128.4, 129.7, 132.6, 138.0, 140.2, 141.0.

Example 4. Fabrication of OLED device

The glass substrate covered with indium tin oxide (ITO having a sheet resistance of 10 OMEGA / m < ² >) was washed with an ultrasonic washing machine containing acetone and 2-propanol, and then rinsed with deionized water. The substrate was dried in a nitrogen atmosphere, and UV-ozone treatment was carried out. All organic and cathode metal layers were deposited by vacuum deposition techniques at ~ 1 x 10 < ^-7 > Torr. At this time, the deposition rate of the organic layer was 0.5 Å / s. The LiF and Al layers were then deposited in another vacuum deposition system without interruption of the vacuum state. At this time, the deposition rates of the LiF and Al layers were 0.1 Å / s and 0.5 Å / s, respectively. After deposition, the device was immediately encapsulated under a nitrogen atmosphere.

The current density-voltage (J-V) and luminance-voltage (L-V) characteristics of the device were measured using a Keithley 2635A Source Meter Unit (SMU) and Konica Minolta CS-100A. Electroluminescence (EL) spectra and CIE color coordinates were measured using a Konica Minolta CS-2000 spectrophotometer.

Experimental Example 1. Analysis of thermal and optical physical properties

The UV-vis, PL spectroscopies and HOMO-LUMO energy levels were measured using the compounds represented by the formulas (1a), (1b) and (1c) prepared in Examples 1 to 3, Respectively.

division T _d
(° C) T _g
(° C) UV? _Max
(nm) PL λ _max
(nm) HOMO
(eV) LUMO
(eV) T ₁
(eV) E _g
(eV) Formula 1a 300 130 293 422 5.41 2.24 2.53 3.17 1b 410 109 350 442 5.44 2.38 2.38 3.06 Formula 1c 500 181 380 424 5.39 2.44 2.33 2.95

As shown in Table 1, the UV-vis absorption peaks of the compounds represented by the formulas (1a), (1b) and (1c) prepared in Examples 1 to 3 were observed at 293, 350 and 380 nm, respectively. The Tg values of the compounds represented by the formulas (1a), (1b) and (1c) prepared in Examples 1 to 3 were high at 130 ° C and 181 ° C, respectively, It was confirmed that they exhibited high characteristics at 300 ° C, 410 ° C and 500 ° C, respectively. The HOMO and LUMO energy levels of the formulas (1a), (1b) and (1c) were 5.5 ± 0.1 eV and 2.2 ± 0.1 eV, respectively. In addition, the T₁ value was 2.4 ± 0.1 eV, indicating that it is suitable for use as an organic material for hole transport.

From the above results, it can be seen that according to the present invention, the compounds of formulas (1a), (1b) and (1c) prepared in Examples 1 to 3 can be easily prepared using Negishi coupling reaction and excellent thermal and optical Which is suitable for use as an organic material for hole transport.

Although the present invention has been described in terms of the preferred embodiments mentioned above, it is possible to make various modifications and variations without departing from the spirit and scope of the invention. It is also to be understood that the appended claims are intended to cover such modifications and changes as fall within the scope of the invention.

Claims

CELLON DERIVATIVES FOR ORGANIC ELECTROLUMINESCENT ELEMENT HOLE TRANSPORT MATERIALS,
[Chemical Formula 1]

In Formula 1,
Each R is independently H, halogen, hydroxy, C1-20 alkoxy, C6-30 aryl, C1-100 alkylamine or C6-100 arylamine,

,

or

to be.

The method according to claim 1,
The celon derivative represented by the above formula (1) is a compound represented by the following formula (1a), (1b) or (1c)
[Formula 1a]

[Chemical Formula 1b]

[Chemical Formula 1c]

A process for producing a hole transporting material for an organic electroluminescence device, which is represented by the following Chemical Formula 1, characterized in that a residue of any one selected from carbazole, triphenylamine and triphenylamine derivatives is subjected to a Negishi coupling reaction Way:
[Chemical Formula 1]

,

or

to be.

The method of claim 3,
The method comprises the steps of reacting a compound represented by the following formula (2) and a compound represented by the following formula (3), (4) or (5) with a Pd catalyst under a solvent:
(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

In the formulas (3) to (5)
L are each independently -I, -Cl, -Br, -F, -OSO 3 H, -SSO 3 H, -OCO-CH 3, -OPO 3 H 2, -OCO-C 6 H 5, -OSO 2 -C ₁ -C ₄ alkyl or a leaving group of OSO ₂ N (C ₁ -C ₄ alkyl).

5. The method of claim 4,
Wherein the reaction is carried out with stirring at 70 to 90 ° C for 10 to 12 hours.

5. The method of claim 4,
The solvent may be selected from the group consisting of distilled water, tetrachloroethane, dimethylacetamide, triethylamine, dimethylformamide, chloroform, methylene chloride, ethyl acetate, methanol, hexane, acetonitrile, toluene, benzene, carbon tetrachloride, pentane, acetone, Wherein the hole transporting material is at least one selected from the group consisting of tetrahydrofuran and dimethyl formaldehyde.

5. The method of claim 4,
The Pd catalyst _{PD (PPH 3) 2 Cl 2} , Pd (ll) acetate, Pd (OAc) 2, PdCl 2 Pd 2 (dab) r , and Pd (PPh ₃₎ organic, characterized in that any selected one of _four A method for manufacturing a hole transporting material for an electroluminescent device.

An organic electroluminescent device comprising a hole transporting material represented by the following formula (1) in a hole transporting layer:
[Chemical Formula 1]

,

or

to be.

9. The method of claim 8,
Wherein the hole transporting material is a compound represented by the following formula (1a), (1b) or (1c):
[Formula 1a]

[Chemical Formula 1b]

[Chemical Formula 1c]