KR20110120108A - Blue fluorescent material and organic light emitting device using the same - Google Patents

Abstract

The present invention relates to a blue fluorescent material and an organic light emitting device using the same.
In the present invention, the diphenylamine derivative is substituted with 1,6-pyrene, and at least one C6 or more aryl group is substituted in the phenyl group, thereby improving luminous efficiency and lifespan.

Description

Blue fluorescent compound and organic electroluminescent device using the same

The present invention relates to a blue fluorescent material and an organic light emitting device using the same. More specifically, the present invention relates to a blue fluorescent material having a high luminous efficiency and an improved lifespan, and an organic light emitting device comprising the same.

Recently, as the size of the display device increases, the demand for a flat display device having less space is increasing. As one of the flat display devices, an organic light emitting diode (OLED) technology, also called an organic light emitting diode (OLED), has a high speed. It has been developed and several prototypes have already been announced.

An organic electroluminescent device is a device that emits light by injecting charge into a light emitting material layer formed between an electron injection electrode (cathode) and a hole injection electrode (anode) and then disappears after pairing electrons and holes. Not only can the device be formed on a flexible transparent substrate such as plastic, but it can also be driven at a lower voltage (less than 10V) compared to a plasma display panel or an inorganic electroluminescent (EL) display. In addition, the power consumption is relatively low, there is an advantage that the color is excellent. In addition, the organic electroluminescent (EL) device can display three colors of green, blue, and red, and thus, has become a subject of much interest as a next-generation rich color display device. Here is a brief look at the process of manufacturing an organic light emitting device,

(1) First, a material such as indium tin oxide (ITO) is deposited on a transparent substrate to form an anode.

(2) forming a hole injecting layer (HIL) on the anode; The hole injection layer is mainly N, N'-diphenyl-N, N'-bis- [4- (phenyl-m-tolyl-amino) -phenyl] -biphenyl-4,4'- It is formed by depositing diamine (DNTPD) to a thickness of 10nm to 60nm.

(3) Next, a hole transport layer (HTL) is formed on the hole injection layer. The hole transport layer is formed by depositing 4,4'-bis [N- (1-naphthyl) -N-phenylamino] -biphenyl (NPD) represented by Chemical Formula 1-2 below about 20 nm to 60 nm.

(4) Next, an emitting material layer (EML) is formed on the hole transport layer. The light emitting material layer is formed of a host and a dopant, and deposits about 20 to 60 nm of 9,10-Bis (1-naphthyl) anthracene (ADN) represented by Chemical Formula 1-3, and a dopant 4,4'-bis [2- (4- (N, N-diphenylamino) phenyl) vinyl] biphenyl (DPAVBi) represented by the following Chemical Formula 1-4 is used at a concentration of 1 to 10%.

(5) Next, an electron transport layer (ETL) and an electron injecting layer (EIL) are successively formed on the light emitting material layer. For example, the electron transport layer is composed of tris (8-hydroxy-quinolate) aluminum (Alq3) represented by the following Chemical Formula 1-5.

(6) Next, a cathode is formed on the electron injection layer, and finally a protective film is formed on the cathode.

Chemical Structural Formula 1-1

Chemical Structural Formula 1-2

Chemical Structural Formula

Chemical Structural Formulas 1-4

Chemical Structural Formula

In the structure as described above, the light emitting material layer implements blue, green, and red to realize full color images.

Various organic compounds have been introduced for forming organic light emitting layers of organic light emitting diodes. However, there was a problem that the lifetime, luminous efficiency and luminance are not sufficient. This is because, as shown in FIG. 1, since the color purity of blue is low, it is difficult to implement dark blue, and there is a problem in implementing a full-color display of natural colors. In order to obtain a high current luminous efficiency (Cd / A), the internal quantum efficiency should be excellent, but there is a problem that it is difficult to obtain a high-purity blue (smaller CIE color coordinate y value) material.

The present invention is to provide a blue fluorescent material for an organic light emitting device that implements high color purity, high luminous efficiency, improved luminous lifetime and low voltage driving.

In addition, the present invention is to provide an organic light emitting display device which can realize high color purity and high brightness image by using the blue fluorescent material and has an improved product life.

In order to solve the above problems, the present invention is represented by the following formula, R1, R2, R3 is hydrogen, deuterium, substituted or unsubstituted C1-C6 alkyl group, substituted or unsubstituted C6 or more aryl group, fluorine, It is selected from cyanine, trifluoromethyl, trimethylsilyl, wherein one or two of R1, R2, R3 provides a blue fluorescent material characterized in that selected from the substituted or unsubstituted C6 or more aryl group.

The other one of the R1, R2, R3 is characterized in that it is selected from florin, cyanine, trifluoromethyl, trimethylsilyl.

The C6 or more aryl group is phenyl, phenyl substituted with deuterium, biphenyl, biphenyl, naphthyl, phenanthrene, terphenyl, fluorenyl ) Is any one of the features.

The alkyl group of C1 ~ C6 is methyl (methyl), ethyl (ethyl), n-propyl (n-propyl), i-propyl (i-propyl), n-butyl (n-butyl), i-butyl (i- butyl) and t-butyl (t-butyl).

In another aspect, the present invention includes a first electrode; A second electrode facing the first electrode; A light emitting material layer is disposed between the first and second electrodes, and the light emitting material layer includes a blue fluorescent material represented by the following chemical formula, and in the following chemical formula, R1, R2, and R3 represent hydrogen, deuterium, and substitution. Or an unsubstituted C1-C6 alkyl group, a substituted or unsubstituted C6 or more aryl group, florin, cyanine, trifluoromethyl, trimethylsilyl, and one or two of R1, R2, and R3 are the substituted or unsubstituted Provided is an organic electroluminescent device characterized by being selected from aryl groups of at least C6.

The other one of the R1, R2, R3 is characterized in that it is selected from florin, cyanine, trifluoromethyl, trimethylsilyl.

The C6 or more aryl group is phenyl, phenyl substituted with deuterium, biphenyl, biphenyl, naphthyl, phenanthrene, terphenyl, fluorenyl ) Is any one of the features.

The alkyl group of C1 ~ C6 is methyl (methyl), ethyl (ethyl), n-propyl (n-propyl), i-propyl (i-propyl), n-butyl (n-butyl), i-butyl (i- butyl) and t-butyl (t-butyl).

The light emitting material layer may include a host capable of transferring electrons or holes, and the blue fluorescent material may include 0.1-20 wt% of the host.

A hole injection layer between the first electrodes; A hole transport layer disposed between the hole injection layer and the light emitting material layer; An electron transport layer on the light emitting material layer; It characterized in that it comprises an electron injection layer located between the electron transport layer and the second electrode.

The blue fluorescent material of the present invention is implemented with high color purity and high luminous efficiency and has an effect of improving the emission life. In particular, by introducing at least one aryl group to the phenyl group, it is characterized in that to satisfy both the luminous efficiency and lifetime.

In addition, the organic light emitting device using the blue fluorescent material can realize a high color purity and high brightness image under low voltage and has an effect of improving product life.

1 is a graph showing a relationship between color purity and visibility (relative sensitivity) of an organic light emitting display device.
2 is a schematic cross-sectional view of an organic light emitting diode of an organic light emitting diode according to an embodiment of the present invention.

Hereinafter, a structure of a blue fluorescent substance according to the present invention, a synthesis example thereof, and an organic light emitting display device using the same will be described.

The blue fluorescent substance according to the embodiment of the present invention is a structure in which a diphenylamine derivative is substituted with 1,6-pyrene, and at least one C6 or more aryl group is substituted for the phenyl group, thereby improving luminous efficiency and lifespan. It is represented by the following formula (2).

Formula 2

That is, in Formula 2, R1, R2, and R3 are selected from hydrogen, deuterium, substituted or unsubstituted C1-C6 alkyl group, substituted or unsubstituted C6 or more aryl group, florin, cyanine, trifluoromethyl, trimethylsilyl One or two of R 1, R 2, and R 3 are selected from the substituted or unsubstituted C 6 or more aryl group.

In addition, the other of the R1, R2, R3 is selected from the above-mentioned florin, cyanine, trifluoromethyl, trimethylsilyl, thereby improving color purity.

For example, the alkyl groups of C1 to C6 are methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl (i-butyl) and t-butyl (t-butyl) can be any one, C6 or more aryl group is phenyl (phenyl), deuterium substituted phenyl (deuterium substituted phenyl), biphenyl (biphenyl), naphthyl ( naphthyl), phenanthrene, phenyl (terphenyl), fluorenyl (fluorenyl) can be any one.

In the present invention, by introducing an amine group containing a phenyl group in which at least one substituted or unsubstituted aryl group is substituted at 1,6 position of pyrene, a blue fluorescent compound having improved luminous efficiency and lifespan was developed. . In addition, since fluorine, cyanine, trifluoromethyl, trimethylsilyl are further substituted with the phenyl group, color purity is improved.

In Formula 2, C6 or more aryl groups which may be selected from one or two of R1, R2, and R3 may be selected from Formula 3 below.

(3)

For example, Chemical Formula 2 is any one of a plurality of substances represented by Chemical Formula 4 below. For convenience of description, each material is numbered A-1 to A-137.

Formula 4

Hereinafter, of the blue fluorescent material for an organic light emitting device according to an embodiment of the present invention, N1, N1, N6, N6-tetra (3,5-diphenylbenzyl) pyrene-1, which is a material represented by A-49 in Chemical Formula 4 The example of the synthesis | combination of the blue fluorescent substance of this invention is demonstrated using, 6-diamine as an example.

Synthetic example

(1) Preparation of bis (3,5-diphenylbenz-1-yl) amine

The bis (3,5-diphenylbenz-1-yl) amine is obtained by the following Scheme 1.

Scheme 1

Specifically, in a two-necked round bottom flask, 1-bromo-3,5-diphenylbenzene (10mmol), 1-amino-3,5, -diphenylbenzene (11mmol), tris (dibenzylideneacetone) dipalladium (0) (0.2mmol), ( ±) -2,2'-bis (diphenylphosphino) -1,1'-binaphthalene (0.3 mmol) and sodium tert-butoxide (14 mmol) are dissolved in toluene (50 mL) and stirred in a 100 ° C bath for 24 hours. . After completion of the reaction, toluene is removed and extracted with dichloromethane and water. After distillation under reduced pressure, the solvent was distilled off under reduced pressure after silica gel column and recrystallized with dichloromethane and petroleum ether. Subsequently, 2.1 g of bis (3,5-diphenylbenz-1-yl) amine crystals were obtained by filtering.

(2) Preparation of N1, N1, N6, N6-tetra (3,5-diphenylbenzyl) pyrene-1,6-diamine

N1, N1, N6, N6-tetra (3,5-diphenylbenzyl) pyrene-1,6-diamine represented by A-49 in Chemical Formula 4 is obtained by the following Scheme 2.

Scheme 2

Bis (3,5-diphenylbenz-1-yl) amine (6.3mmol), 1,6-dibromopyrene (3mmol), tris (dibenzylideneacetone) dipalladium (0) (0.15mmol), tri-tert-butylphosphine (0.1 mol) and sodium tert-butoxide (10 mmol) are dissolved in toluene (30 mL) and stirred in a 100 ° C. bath for 24 hours. After completion of the reaction, toluene is removed and extracted with dichloromethane and water. After distillation under reduced pressure, the solvent was distilled off under reduced pressure after silica gel column and recrystallized using dichloromethane and acetone. Thereafter, the resultant was filtrated, and a passion agent was carried out to obtain compound A-49.

Hereinafter, Experimental Examples 1 to 4, which fabricate an organic light emitting device using a blue fluorescent material according to the embodiment of the present invention, and Comparative Examples of manufacturing an organic light emitting device using a conventional blue fluorescent material By comparing the performance of the blue fluorescent substance and the organic light emitting device using the same according to the present invention.

Experimental Example 1

The light emitting area of the indium tin oxide (ITO) layer on the substrate was patterned to have a size of 3 mm x 3 mm and then washed. After mounting the substrate in a vacuum chamber, the process pressure was 1 × 10 −6 torr, and about 700 kPa of DNTPD, about 300 kPa of NPD, and the host material AND were represented by A-1 in the formula (4) on the ITO layer. 4% was added and sequentially laminated to a thickness of about 250 kPa, Alq3 about 350 kPa, LiF about 5 kPa and Al about 1000 kPa.

The experimental results showed 553cd / m2 (4.3V) at 10mA / cm2 with CIEx = 0.153 and y = 0.106. The half life is 1320 hr at 3000 cd / m2.

Experimental Example 2

The light emitting area of the indium tin oxide (ITO) layer on the substrate was patterned to have a size of 3 mm x 3 mm and then washed. After mounting the substrate in a vacuum chamber, the process pressure was 1X10-6torr, and then about 700 kPa of DNTPD, about 300 kPa of NPD, and the host material AND were represented by A-13 in Chemical Formula 4 as a dopant. 4% was added and sequentially laminated to a thickness of about 250 kPa, Alq3 about 350 kPa, LiF about 5 kPa and Al about 1000 kPa.

Experimental results showed that 598cd / m2 (4.1V) at 10mA / cm2, CIEx = 0.151, y = 0.110. The half life is 1980 hr at 3000 cd / m2.

Experimental Example 3

The light emitting area of the indium tin oxide (ITO) layer on the substrate was patterned to have a size of 3 mm x 3 mm and then washed. After mounting the substrate in a vacuum chamber, the process pressure was 1 × 10 −6 torr, and then about 700 kPa of DNTPD, about 300 kPa of NPD, and the host material AND were represented by A-49 in Chemical Formula 4 as a dopant. 4% was added and sequentially laminated to a thickness of about 250 kPa, Alq3 about 350 kPa, LiF about 5 kPa and Al about 1000 kPa.

As a result, 728 cd / m 2 (4.3 V) was shown at 10 mA / cm 2, with CIEx = 0.135 and y = 0.145. The half life is 2700 hr at 3000 cd / m2.

Experimental Example 4

The light emitting area of the indium tin oxide (ITO) layer on the substrate was patterned to have a size of 3 mm x 3 mm and then washed. After mounting the substrate in a vacuum chamber, the process pressure was 1X10-6torr, and about 700 kPa of DNTPD, about 300 kPa of NPD, and the host material AND were represented by A-58 in Chemical Formula 4 as a dopant. 4% was added and sequentially laminated to a thickness of about 250 kPa, Alq3 about 350 kPa, LiF about 5 kPa and Al about 1000 kPa.

As a result, 674 cd / m 2 (4.2 V) was shown at 10 mA / cm 2, and CIEx = 0.136 and y = 0.124. The half life is 2300 hr at 3000 cd / m2.

Comparative example

The light emitting area of the indium tin oxide (ITO) layer on the substrate was patterned to have a size of 3 mm x 3 mm and then washed. After mounting the substrate in a vacuum chamber, the process pressure was 1X10-6torr, and DNPPD about 500Å, NPD about 300Å, and DPAVBi was added as a dopant to the host material AND about 250 펀, Alq3 about It laminated | stacked sequentially by the thickness of 350 kW, LiF about 5 kPa, and Al about 1000 kPa.

Experimental results showed that 724cd / m2 (5.4V) at 10mA / cm2, CIEx = 0.144, y = 0.205. The half life is 650 hr at 3000 cd / m2.

Here, each of the DNTPD, the NPD, the AND, the DPVBi, and the Alq3 is represented by Formulas 1-1 to 1-5.

Comparative results of the above Experimental Examples 1 to 4 and Comparative Example are shown in Table 1 below. The unit of voltage is V, the unit of current is mA / cm2, the unit of luminance is cd / m2, and the unit of life is time (h).

As can be seen from Table 1, in Experimental Examples 1 to 4 it can be seen that the internal quantum efficiency and life is improved. In addition, when compared with the comparative example, it can be seen that the driving is possible at a low voltage and the CIE (Y) value is lowered to improve the color purity.

Voltage electric current Luminance Internal Quantum Efficiency CIE (X) CIE (Y) life span Experimental Example 1 4.3 0.9 553 6.7 0.153 0.106 1320 Experimental Example 2 4.1 0.9 598 6.5 0.151 0.110 1980 Experimental Example 3 4.3 0.9 728 6.8 0.135 0.145 2700 Experimental Example 4 4.2 0.9 674 6.6 0.136 0.124 2300 Comparative example 5.4 0.9 724 5.1 0.144 0.205 650

An embodiment of an organic light emitting diode of the organic light emitting diode including the blue fluorescent material is shown in FIG. 2.

As illustrated, the organic light emitting diode includes first and second substrates (not shown) facing each other and an organic light emitting diode (E) formed between the first and second substrates (not shown). .

The organic light emitting diode E is an organic light emitting layer 120 formed between the first electrode 110 serving as an anode, the second electrode 130 serving as a cathode, and the first and second electrodes 110 and 130. )

The first electrode 110 is formed of a material having a relatively high work function, for example, indium tin oxide (ITO), and the second electrode 130 is formed of a material having a relatively low work function, for example. For example, it is made of aluminum (Al) or aluminum alloy (AlNd). In addition, the organic light emitting layer 130 includes red, green, and blue organic light emitting patterns.

The organic light emitting layer 130 has a multilayer structure, that is, a hole injection layer (HTL) 121 and a hole transporting layer (hole transporting layer; HIL) sequentially from the first electrode 110 in order to maximize luminous efficiency. ) 122, an emitting material layer (EML) 123, an electron transporting layer 124, and an electron injection layer 125.

Here, the light emitting material layer 123 includes a blue fluorescent material represented by Chemical Formula 2. The blue light emitting pattern of the light emitting material layer 123 is formed by adding a blue fluorescent material represented by Chemical Formula 2 as a dopant to a host which is a material capable of transferring electrons and holes. Here the dopant is added at about 0.1-20 wt%. For example, the host may be AND represented by Formula 1-3.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art various modifications and changes of the present invention without departing from the spirit and scope of the present invention described in the claims below I can understand that you can.

110: first substrate
120: organic light emitting layer
123: light emitting material layer
130: second substrate

Claims (10)

Represented by the following formula, R1, R2, R3 is selected from hydrogen, deuterium, substituted or unsubstituted C1-C6 alkyl group, substituted or unsubstituted C6 or more aryl group, florin, cyanine, trifluoromethyl, trimethylsilyl Wherein one or two of R1, R2, and R3 are selected from the substituted or unsubstituted C6 or more aryl groups.

The method of claim 1,
The other one of R1, R2, R3 is blue fluorescent material, characterized in that selected from the florin, cyanine, trifluoromethyl, trimethylsilyl.
The method of claim 1,
The C6 or more aryl group is phenyl, phenyl substituted by deuterium, biphenyl, biphenyl, naphthyl, phenanthrene, terphenyl, fluorenyl Blue fluorescent material characterized in that any one of).
The method of claim 1,
The alkyl group of C1 ~ C6 is methyl (methyl), ethyl (ethyl), n-propyl (n-propyl), i-propyl (i-propyl), n-butyl (n-butyl), i-butyl (i- butyl) and t-butyl (t-butyl) characterized in that the blue fluorescent substance.
A first electrode;
A second electrode facing the first electrode;
A light emitting material layer positioned between the first and second electrodes,
The light emitting material layer includes a blue fluorescent material represented by the following formula, wherein R1, R2, R3 is hydrogen, deuterium, substituted or unsubstituted C1 ~ C6 alkyl group, substituted or unsubstituted C6 or more aryl Group, florin, cyanine, trifluoromethyl, trimethylsilyl, and one or two of R1, R2, and R3 are selected from the substituted or unsubstituted C6 or more aryl group.

The method of claim 5, wherein
The other one of the R1, R2, R3 is characterized in that the organic electroluminescent device is selected from among the florin, cyanine, trifluoromethyl, trimethylsilyl.
The method of claim 5, wherein
The C6 or more aryl group is phenyl, phenyl substituted by deuterium, biphenyl, biphenyl, naphthyl, phenanthrene, terphenyl, fluorenyl An organic light emitting device, characterized in that any one of).
The method of claim 5, wherein
The alkyl group of C1 ~ C6 is methyl (methyl), ethyl (ethyl), n-propyl (n-propyl), i-propyl (i-propyl), n-butyl (n-butyl), i-butyl (i- An organic electroluminescent device characterized by any one of butyl) and t-butyl (t-butyl).
The method of claim 5, wherein
The light emitting material layer includes a host capable of transferring electrons or holes, and the blue fluorescent material is characterized in that 0.1 to 20% by weight of the host.
The method of claim 5, wherein
A hole injection layer between the first electrodes;
A hole transport layer disposed between the hole injection layer and the light emitting material layer;
An electron transport layer on the light emitting material layer;
And an electron injection layer disposed between the electron transport layer and the second electrode.

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