JPH03162483A - Electroluminescent element - Google Patents

Abstract

PURPOSE:To provide an electroluminescent element having a fluorescent light- emitting layer consisting of a fluorescent thin film containing a quinolone compound and enabling an organic fluorescent material to emit light in high efficiency and luminance. CONSTITUTION:The objective luminescent element has a fluorescent light- emitting layer consisting of a fluorescent thin film having a thickness of <=1mum and containing a quinolone compound expressed by formula [R<1> is H or alkyl; R<3> is H, alkyl, carboxyl, alkanoyl, alkoxycarbonyl, cyano or aryl; R<4> is H, alkyl, haloalkyl, carboxyl, alkanoyl, alkoxycarbonyl or alkoxy; R<5> is H, amino or (di)alkylamino; R<6> is H; R<7> is OH, amino, (di)alkylamino or alkoxy; R<8> is H or alkyl]. It is preferable to insert an organic electron-transfer layer between the cathode and the fluorescent material layer.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an electroluminescent device, and more particularly to an electroluminescent device formed using an organic compound as a light emitter.

BACKGROUND ART As shown in FIG. 2, this type of electroluminescent device uses an organic phosphor thin film 3 made of an organic compound and laminated on each other between a metal electrode 1 serving as a cathode and a transparent electrode 2 serving as an anode. Those with a two-layer structure in which a hole transport layer 4 is arranged, and those with a third layer structure.
As shown in the figure, it has a three-layer structure in which an organic electron transport layer 5, an organic phosphor thin film 3, and an organic hole transport layer 4 are stacked between a metal MS electrode 1 and a transparent electrode 2. something is known. Here, the organic hole transport layer 4 has a function of facilitating injection of holes from the anode and a function of blocking electrons, and the organic electron transport layer 5 has a function of facilitating injection of electrons from the cathode. ing.

In these electroluminescent devices, the transparent electroluminescent I! A glass substrate 6 is disposed on the outside of the ffi2, and excitons are generated by recombination of electrons injected from the metal electrode 1 and holes released from the transparent electrode 2, and these excitons are deactivated by radiation. In this process, light is emitted, and this light is emitted to the outside via the transparent electrode 2 and the glass substrate 6.

Furthermore, in the conventional electroluminescent device having the above-mentioned configuration,
Products with specific color fluorescence bands have been developed, but
Furthermore, in order to emit light of various other colors, it is desired to develop electroluminescent devices using more types of organic phosphors.

Summary of the Invention [Object of the Invention] The present invention has been made to satisfy the above-mentioned conventional needs, and it is an object of the present invention to provide an electroluminescent device that can efficiently cause organic phosphors to emit light at high brightness. With the goal.

[Structure of the Invention] The electroluminescent device according to the present invention is an electroluminescent device having a structure in which a phosphor emitting layer and a hole transport layer made of an organic compound and stacked on each other are arranged between a cathode and an anode,
The phosphor light-emitting layer is characterized in that it is made of a phosphor thin film containing a quinolone compound or an azaquinolone compound.

Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 1 is a structural diagram showing one embodiment of the present invention, in which the same parts as in FIGS. 2 and 3 are given the same reference numerals.

In the figure, a thin film of aluminum with a thickness of 1500 mm is used for the metal electrode 1 serving as the cathode. In addition, in the cathode 1,
Metals with a small cutting function, such as aluminum, magnesium, indium, silver, or alloys thereof, having a thickness of about 500 mm or more can be used.

The transparent electrode 2, which is an anode, is made of indium tin oxide (1
．． T. O. ) is used with a thickness of 2000A.

Further, the anode 2 is made of a conductive material with a large work function, for example, an I.D. T. 0.
Alternatively, gold having a thickness of about 800 to 1,500 gold can be used. Note that when gold is used as the electrode material, the electrode 2 becomes translucent.

An organic phosphor thin film 7 and an organic hole transport layer 4 are arranged between the metal electrode 1 and the transparent electrode 2, which are laminated in order from the top in the figure.

For the organic hole transport layer 4, a thin film of a triphenylamine derivative, for example, a compound of the following formula (I) is used.

In addition, the organic hole transport layer 4 further includes the following formulas (II) to (
XII) CTM (Carrier Trans
Compounds known as slLing Materials) can be used.

As the organic phosphor thin film 7, a phosphor thin film containing a quinolone compound or an azaquinolone compound is used. The thickness of the organic phosphor thin film 7 is set to 1 μm or less.

As the organic phosphor thin film of a quinolone compound, one represented by the following structural formula (A1) is used.

However, in the above structural formula (A1), Rl is hydrogen or an alkyl group, R3 is hydrogen, an alkyl group, a carboxyl group, an alkanoyl group, an alkoxycarbonyl group, a cyano group, or an aryl group, and R4 is hydrogen or an alkyl group. group, haloalkyl group, carboxyl group, alkanoyl group, alkoxy carbonyl group, or alkoxy group, and R5 is hydrogen, amino group. It is an alkylamino group or a dialkylamino group, R6 is hydrogen, and R7 is a hydroxyl group, an amino group, etc. Alkylamino group. A functional group in which R8 is a dialkylamino group or an alkoxy group, and R8 is hydrogen or an alkyl group (However, in R l and R II, the alkyl component preferably has 1 to 5 carbon atoms, but may have 6 or more carbon atoms. The aryl component preferably has 6 to 14 carbon atoms, but may have 18 or more carbon atoms.

The quinolone compound (A1) that forms this phosphor thin film is
No. of functional groups in Table 1. l-No. l5, No. 2
0~No. 25 and no. Those having 28 combinations are preferred.

Furthermore, in the above structural formula (A1), R3, R5 and R8 are hydrogen, and R6 and R7 together form a fused carbocycle or a heterocycle, a quinolone compound of the following formula (A1a) (
However, the alkyl component preferably has 1 to 5 carbon atoms.
(6 or more) may also be used.

For example, the following (AI-26), (Al-27), (A
1-16) and (Alb) quinolone compounds.

When forming a phosphor thin film using this quinolone compound of formula (Alb), the number of functional groups X, Y, and R in Table 2 is determined. 1
7~No. Those having 19 combinations are preferred.

Table 2 (Me-CHs) As the organic phosphor thin film of an azaquinolone compound, one represented by the following structural formula (A2) can also be used.

However, Rl is hydrogen or an alkyl group, and R3 is hydrogen. Alkyl group. Carboxyl group. It is an alkanoyl group, an alkoxycarbonyl group, a cyano group, or an aryl group, and R' is hydrogen. It is an alkyl group, a haloalkyl group, a carboxyl group, an alkanoyl group, an alkoxycarbonyl group, or an alkoxy group, and R7 is a hydroxyl group or an amino group. A functional group that is an alkylamino group, a dialkylamino group, or an alkoxy group (however, in R l and R 7, alkyl preferably has 1 to 5 carbon atoms, but 6
Aryl carbon atoms preferably have 6 to 14 carbon atoms, but may have 18 or more carbon atoms.

Quinolone compound (A2) forming this phosphor thin film teeth, No. of functional groups in Table 3. 29 ~No. 44 pairs It is preferable to have a combination.

As the organic phosphor thin film of an azaquinolone compound, one represented by the following structural formula (A 3 -4 5) can also be used.

In addition, the electroluminescent device described above has a two-layer structure in which the organic phosphor thin film 7 and the organic hole transport layer 4 are arranged between the cathode 1 and the anode 2. A three-layer structure in which an organic electronic transport layer 5 made of a berylenetetracarpoxyl derivative of the formula (XX) is also provided has the same effect.

Effects of the Invention As explained above, the electroluminescent device according to the present invention has a structure in which a phosphor emitting layer and a hole transport layer made of an organic compound and stacked on each other are arranged between a cathode and an anode. Since the phosphor emitting layer is made of a phosphor thin film containing a quinolone compound or an azaquinolone compound, it is possible to efficiently emit light with high brightness at a low voltage.

EXAMPLE An electroluminescent device according to an example of the present invention was prepared and emitted light.

First, a transparent electrode, which is an anode, is placed on a glass substrate. T. 0
．． A film having a thickness of 2000λ was prepared. Aluminum was used for the metal electrode 1 serving as the cathode.

For the organic hole transport layer 4, the triphenylamine derivative of the above formula (1) was used.

As the organic phosphor thin film 7, No. 1 in the above table is used. 4 below (
A quinolone compound of formula AI-4) was used.

The film forming conditions such as degree of vacuum, evaporation rate, and film thickness when forming the hole transport layer, phosphor thin film, and cathode are as shown in Table 4. The luminescence characteristics obtained by applying .

[Brief explanation of the drawing]

FIG. 1 is a structural diagram showing an embodiment of the present invention, and FIG. 3 is a structural diagram showing a conventional example. Explanation of symbols for main parts 1...Metal electrode (cathode) 2...Transparent electrode (anode) 4...Organic hole transport layer 6...Glass Substrate 7...Organic phosphor thin film Fig. 2

Claims (5)

[Claims] (1) An electroluminescent device having a structure in which a phosphor-emitting layer and a hole-transporting layer made of an organic compound and stacked on each other are arranged between a cathode and an anode, and the phosphor-emitting layer has the following structural formula (A1). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ In the above structural formula (A1), R^1 is hydrogen or an alkyl group, and R^3 is hydrogen, an alkyl group, a carboxyl group,
an alkanoyl group, an alkoxycarbonyl group, a cyano group, or an aryl group; R^4 is hydrogen, an alkyl group, a haloalkyl group, a carboxyl group, an alkanoyl group, an alkoxycarbonyl group, or an alkoxy group; R^5
is hydrogen, amino group, alkylamino group or dialkylamino group, R^6 is hydrogen, R^7 is hydroxyl group, amino group, alkylamino group, dialkylamino group or alkoxy group, R^8 is An electroluminescent device comprising a phosphor thin film containing a quinolone compound whose functional group is hydrogen or an alkyl group. (2) An electroluminescent device having a structure in which a phosphor-emitting layer and a hole-transporting layer made of an organic compound and stacked on each other are arranged between a cathode and an anode, wherein the phosphor-emitting layer has the following structural formula (A1a). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ In the above structural formula (A1), R^1 is hydrogen or an alkyl group, R^4 is an alkyl group or a haloalkyl group, and R^6 and R ^7 is an electroluminescent device characterized by comprising a phosphor thin film containing a quinolone compound which is taken together to form a condensed carbocyclic ring or a heterocyclic ring. (3) An electroluminescent element having a structure in which a phosphor-emitting layer and a hole-transporting layer made of an organic compound and stacked on each other are arranged between a cathode and an anode, the phosphor-emitting layer having the following structural formula (
A2), ▲There are mathematical formulas, chemical formulas, tables, etc.▼ In the above structural formula (A2), R^1 is hydrogen or an alkyl group, and R^3 is hydrogen, an alkyl group, a carboxyl group,
It is an alkanoyl group, an alkoxycarbonyl group, a cyano group, or an aryl group, and R^4 is hydrogen, an alkyl group, a haloalkyl group, a carboxyl group, or an alkanoyl group. It is an alkoxycarbonyl group or an alkoxy group, and R^7
An electroluminescent device comprising a phosphor thin film containing an azaquinolone compound whose functional group is a hydroxyl group, an amino group, an alkylamino group, a dialkylamino group, or an alkoxy group. (4) An electroluminescent device having a structure in which a phosphor-emitting layer and a hole-transporting layer made of an organic compound and stacked on each other are arranged between a cathode and an anode, the phosphor-emitting layer having the following structural formula (
A3), ▲There are mathematical formulas, chemical formulas, tables, etc.▼ An electroluminescent device characterized by being made of a phosphor thin film containing a compound represented by the following. (5) The electroluminescent device according to any one of claims 1 to 4, characterized in that an organic electron transport layer is disposed between the cathode and the phosphor layer.