TWI614928B - Organic light emitting device - Google Patents

Abstract

The present invention relates to an organic light-emitting device, and includes a first cathode; a second cathode; and an anode disposed between the first cathode and the second cathode, wherein the first light-emitting unit is disposed at the first cathode A second light emitting unit is disposed between the second cathode and the anode, and the first light emitting unit and the second light emitting unit are connected in parallel with each other, and the first light emitting unit includes a first light emitting layer. And an organic material layer comprising a compound as shown in Formula 1 is disposed between the first light-emitting layer and the anode, the second light-emitting unit includes a second light-emitting layer, and comprises an organic material of a compound as shown in Formula 1. A layer is disposed between the second luminescent layer and the anode.

Description

Organic light emitting device

The present invention relates to an organic light-emitting device.

The organic light-emitting device converts current into visible light by injecting electrons and holes from the two electrodes into the organic material layer. The organic light-emitting device may have a multi-layer structure including two or more organic material layers. For example, the organic light-emitting device may further include an electron or hole injection layer, an electron or a hole, in addition to the light-emitting layer. A barrier layer, or an electron or hole transport layer.

Recently, the organic light-emitting device has been used for a variety of purposes, and has been actively studied for materials which can improve the performance of the organic light-emitting device.

The present invention provides an organic light-emitting device having a novel structure.

An exemplary embodiment of the present invention includes: a first cathode; a second cathode; and an anode disposed between the first cathode and the second cathode, wherein the first light emitting unit is disposed on the first cathode and the anode Anode a second light emitting unit is disposed between the second cathode and the anode, and the first light emitting unit and the second light emitting unit are connected in parallel with each other, the first light emitting unit includes a first light emitting layer, and includes the following An organic material layer of the compound of Formula 1 is disposed between the first light-emitting layer and the anode, and the second light-emitting unit includes a second light-emitting layer and includes an organic material layer of a compound represented by Formula 1 below The system is disposed between the second luminescent layer and the anode.

In Formula 1, R ¹ to R ⁶ are the same or different from each other, and are each independently hydrogen, a halogen atom, a nitrile group (-CN), a nitro group (-NO ₂ ), a sulfonyl group (-SO ₂ R), Athene (-SOR), sulfonamide (-SO ₂ NR), sulfonate (-SO ₃ R), trifluoromethyl (-CF ₃ ), ester (-COOR), guanamine (-CONHR) Or -CONRR'), a substituted or unsubstituted linear or branched C ₁ to C ₁₂ alkoxy group, a substituted or unsubstituted linear or branched C ₁ to C ₁₂ alkyl group, once substituted Or unsubstituted linear or branched C ₂ to C ₁₂ alkenyl, substituted or unsubstituted aromatic or non-aromatic heterocyclic ring, substituted or unsubstituted aryl group, substituted or unsubstituted a substituted mono- or diarylamine, or a substituted or unsubstituted arylalkylamine, wherein each of R and R' is a substituted or unsubstituted C ₁ to C ₆₀ alkyl group, once substituted or not Substituted aryl, or substituted or unsubstituted 5- to 7-membered heterocyclic ring.

The organic light-emitting device according to the present invention can be applied to a two-emission type organic light-emitting device by symmetrically connecting the two light-emitting units to the upper and lower sides of the anode (which is a common electrode). Further, according to the organic light-emitting device of the present invention, an electrode material having various work functions can be used by passing a compound including the compound of the formula 1 in the organic material layer.

1 is a schematic view showing a stacked structure of an organic light-emitting device according to the related art.

2 is a schematic view showing a stacked structure of an organic light-emitting device according to an exemplary embodiment of the present invention.

3 is a schematic view showing a stacked structure of an organic light-emitting device according to an exemplary embodiment of the present invention.

Hereinafter, the embodiments of the present invention will be described in detail.

In general, an organic light-emitting device in the related art has a structure in which light is emitted only in a single direction. In this structure, when the anode and cathode are transparent A dual light-emitting organic light-emitting device can be realized when the electrode is used. However, when light is emitted from both sides, the brightness of the device will be reduced by half compared to the brightness of the single side.

In addition, FIG. 1 is a schematic diagram of a stacked structure of an organic light-emitting device according to the related art. Specifically, the related art organic light-emitting device may include an anode, a cathode, and an organic material layer including a light-emitting layer disposed between the anode and the cathode. In particular, the related art organic light-emitting device may include two light-emitting layers in the organic material layer to emit white light, but the cavity lengths of the light-emitting layers may be different from each other, and the colors of the light emitted from the two sides may be different from each other. Therefore, it has a problem that it is difficult to achieve a desired color.

Therefore, in the present invention, the structure of two or more light-emitting units which are connected in parallel in the vertical direction is introduced, and in particular, in the organic light-emitting device, the electrode structure is further simplified by using the anode as a common electrode. Developed.

An organic light-emitting device according to an exemplary embodiment of the present invention includes: a first cathode; a second cathode; and an anode disposed between the first cathode and the second cathode, wherein the first light-emitting unit is disposed in the first Between a cathode and the anode, a second light emitting unit is disposed between the second cathode and the anode, and the first light emitting unit and the second light emitting unit are connected in parallel with each other, and the first light emitting unit includes a first light emitting unit a layer, and an organic material layer including a compound as shown in Formula 1 is disposed between the first light-emitting layer and the anode, and the second light-emitting unit includes a second light-emitting layer, and includes a compound as shown in Formula 1. The organic material layer is disposed between the second light emitting layer and the anode.

In the present invention, the at least one includes a compound as shown in Formula 1. The organic material layer is in contact with the anode. In addition, the organic material layer including the compound shown in Formula 1 between the first light-emitting layer and the anode, and the between the second light-emitting layer and the anode are included as shown in Formula 1. The organic material layer of the compound can be in contact with the anode.

In the present invention, the compound of the formula 1 can be exemplified by the following compounds of the formula 1-6, but is not limited thereto.

[Equation 1-6]

Other examples of Formula 1, or methods of synthesis, and various features are described in U.S. Patent Application No. 2002-0158242, and U.S. Patent Nos. 6,436,559 and 4,780,536, the entire contents of each of which are incorporated herein.

Hereinafter, each layer constituting the organic light-emitting device according to an exemplary embodiment of the present invention will be described in detail. The material of each of the following layers may be a single material or a combination of two or more materials.

In the present invention, n-type means n-type semiconductor characteristics. In other words, an n-type semiconductor is an organic material layer having electrons injected or transferred in a LUMO energy level, and the organic material layer has characteristics of a material having an electron mobility higher than a hole mobility. Conversely, p-type means p-type semiconductor characteristics. In other words, a p-type semiconductor is an organic material layer having the characteristics of a hole in the highest occupied molecular orbital (HOMO) energy level injection or transmission, and the organic material layer has the characteristics of a material having a hole mobility higher than the electron mobility. . In the present invention, "an organic material layer transporting charge at HOMO energy level" has the same meaning as a p-type organic material layer; and "an organic material layer transports charge at LUMO energy level" and an n-type organic material layer Can have the same meaning Righteousness.

In the present invention, the energy level refers to the magnitude of energy. According to this, even when the energy level is expressed by the negative direction of the degree of vacuum (negative (-) direction), the energy level is interpreted as an absolute value with respect to one of the energy values. For example, the HOMO energy level refers to the distance from the unoccupied vacuum level to the highest occupied molecular orbital. Also, the LUMO energy level refers to the distance from the unoccupied vacuum level to the lowest unoccupied molecular orbital.

In the present invention, a charge refers to an electron or a hole.

anode

The anode includes a metal, a metal oxide, or a conductive polymer. The conductive polymer can include a conductive polymer. For example, the anode can have a work function value of from about 3.5 eV to about 5.5 eV. Examples of conductive materials include carbon, aluminum, vanadium, chromium, copper, zinc, silver, gold, other metals, or alloys thereof; zinc oxide, indium oxide, tin oxide, indium tin oxide (ITO), and others Similar to metal oxides; mixtures of oxides and metals, such as ZnO:Al and SnO ₂ :Sb, and the like. Regarding the material as the anode, a transparent or opaque material can be used. In the case of a structure in which light is emitted toward the anode, a transparent anode can be formed. Here, as long as the light emitted from the organic light-emitting layer can be transmitted with sufficient transparency, the transmittance of the light is not particularly limited.

In particular, the organic light-emitting device of the present invention can be more effectively applied to a dual-emissive organic light-emitting device by including the anode as a common electrode.

In the present invention, the p-type organic material layers may each be set at the first Between the luminescent layer or the second luminescent layer and the anode. The p-type organic material layer may be a hole injection layer (HIL) or a hole transport layer (HTL).

As the material of the p-type organic material layer, an arylamine compound can be used. As an example of an arylamine compound, it is a compound of the following formula 2.

In Formula 2, Ar ₁ , Ar ₂ , and Ar ₃ are each independently hydrogen or a hydrocarbon group, and at least one of Ar ₁ , Ar ₂ , and Ar ₃ may include an aromatic hydrocarbon substituent, and each of them is substituted. The groups may be identical to each other or may be composed of different substituents.

Specific examples of Formula 2 include the following chemical formulas, and the exemplary embodiments of the present invention are not always limited thereto.

The p-type organic material layer is different from the layer having the p-type semiconductor property of the organic material doped with the p-type dopant in the related art. The p-type organic material layer does not exhibit p-type semiconductor characteristics by the p-type dopant, however the p-type organic material layer itself includes an organic material having p-type semiconductor characteristics.

Light-emitting layer (EML)

Since the hole transmission and the electron transmission occur simultaneously in the first light-emitting layer and the second light-emitting layer of the present invention, the first light-emitting layer and the second light-emitting layer can have both n-type characteristics and p-type characteristics. For convenience, when the electron transport is faster than the hole transport, the light-emitting layer can be defined as an n-type light-emitting layer; and when the hole transport is faster than the electron transport, the light-emitting layer can be defined as a p-type light-emitting layer.

The n-type light-emitting layer includes: tris-(8-hydroxyquinoline)aluminum (Alq ₃ ); 8-hydroxyquinolinium (BAlq); a benzoxazole-based compound; a benzothiazole compound ( Benzthiazole-based compound or benzimidazole-based compound; polyfluorene-based compound; sila cyclopentadiene (silole)-based compound, and the like However, the invention is not limited thereto.

The p-type light-emitting layer includes: a carbazole-based compound; an anthracene-based compound; a polyphenylenevinylene (PPV)-based polymer; or a spiro compound (spiro) Compound), and the like, but the invention is not limited thereto.

Electron Transport Layer (ETL) and Hole Transport Layer (EIL)

In the present invention, the n-type organic material layer may be respectively disposed between the first light-emitting layer or the second light-emitting layer and the cathode. The n-type organic material layer may be an electron injection layer (EIL) or an electron transport layer (ETL).

The material for the n-type organic material layer is preferably a material having a high electron mobility to transport electrons. The electron transport layer comprises: tris-(8-hydroxyquinoline)aluminum (Alq ₃ ); an organic compound including an Alq ₃ structure; a hydroxyflavone-metal complex; or a heterocyclic pentane A sila cyclopentadiene (silole)-based compound; similar thereto, but is not limited thereto.

Further, as a material of the n-type organic material layer, a material conventionally used for the n-type organic material layer can be utilized as an electron injecting or transporting material. For example, materials as described below may be used, but are not limited thereto. For example, as a specific example of the material of the n-type organic material layer, a compound having an epoxy group selected from the group consisting of an imidazole group, an oxazole group, a thiazole group, and a quinolyl group can be used. (quinoline group) and phenanthroline group.

Having a compound selected from the group consisting of imidazolyl, oxazolyl, and thiazolyl A specific example is a compound of the following formula 3 or 4.

In Formula 3, R1 to R4 may be the same or different, and each independently hydrogen; a C ₁ to C ₃₀ alkyl, which is substituted by one or more lines of substituted or unsubstituted, selected from the group consisting of: Halogen, amino group, nitrile group, nitro group, C ₁ to C ₃₀ alkyl group, C ₂ to C ₃₀ alkenyl group, C ₁ to C ₃₀ alkoxy group, C ₃ to a group consisting of a C ₃₀ cycloalkyl group, a C ₃ to C ₃₀ heterocycloalkyl group, a C ₅ to C ₃₀ aryl group, and a C ₂ to C ₃₀ heteroaryl group; a C ₃ to C ₃₀ cycloalkyl group, Substituted or unsubstituted by one or more groups selected from the group consisting of: halogen, amino, nitrile, nitro, C ₁ to C ₃₀ alkyl, C ₂ to C ₃₀ alkenyl, C ₁ to C ₃₀ group consisting of alkoxy, C ₃ to C ₃₀ cycloalkyl, C ₃ to C ₃₀ heterocycloalkyl group, C ₅ to C ₃₀ aryl, and C ₂ to C ₃₀ heteroaryl group; a C ₅ a C ₃₀ aryl group substituted or unsubstituted with one or more groups selected from the group consisting of halogen, amino, nitrile, nitro, C ₁ to C ₃₀ alkyl, C ₂ to C ₃₀ Alkenyl, C ₁ to C ₃₀ alkoxy, C ₃ to C ₃₀ cycloalkyl, C ₃ to C ₃₀ heterocycloalkyl, C ₅ to C ₃₀ aryl, and C ₂ to C ₃₀ a group consisting of heteroaryl groups; or a C ₂ to C ₃₀ heteroaryl group substituted or unsubstituted with one or more groups selected from the group consisting of halogen, amino, nitrile, nitro , C ₁ to C ₃₀ alkyl, C ₂ to C ₃₀ alkenyl, C ₁ to C ₃₀ alkoxy, C ₃ to C ₃₀ cycloalkyl, C ₃ to C ₃₀ heterocycloalkyl, C ₅ to C ₃₀ a group consisting of an aryl group and a C ₂ to C ₃₀ heteroaryl group; and may form an aliphatic, aromatic, aliphatic heterocyclic ring, or an aromatic heterocyclic fused ring or a spiro ring bonding adjacent group Ar ¹ is a hydrogen atom, a substituted or unsubstituted aromatic ring, or a substituted or unsubstituted aromatic heterocyclic ring; X is O, S, or NR ^a ; and R ^a can be hydrogen, a C _{a 1} to C ₇ aliphatic hydrocarbon, an aromatic ring, or an aromatic heterocyclic ring.

In Formula 4, X is O, S, NR ^b or a C ₁ to C ₇ divalent hydrocarbon group; each of A, D, and R ^b is hydrogen, a nitrile group (-CN), a nitro group (-NO _{2 )} a C ₁ to C ₂₄ alkyl group, a substituted aromatic ring comprising a C ₅ to C ₂₀ aromatic ring or a hetero atom, a halogen, or an alkylene group or an alkyl group including a hetero atom, which may Combines with adjacent rings to form a fused ring; A and D may be bonded to each other to form an aromatic ring or a heteroaryl ring; when n is 2 or more, B is substituted or unsubstituted alkyl or aromatic a group which is conjugated or non-conjugated to a plurality of heterocyclic rings as a linking unit, and when n is 1, B is a substituted or unsubstituted alkyl or aryl group; and n is an integer from 1 to 8. .

Examples of the compound of Chemical Formula 3 include Korean Patent Application Compounds of the type disclosed in U.S. Patent No. 5,645,948 and WO 05/097756. All of the above documents have been incorporated in the specification of the present invention.

Specifically, the compound of Formula 3 also includes a compound of Formula 5 below.

In Formula 5, R ⁵ to R ⁷ are the same or different from each other, and are each independently hydrogen, a C ₁ to C ₂₀ aliphatic hydrocarbon, an aromatic ring, an aromatic heterocyclic ring, or an aliphatic or aromatic group. a fused ring; an Ar-bond-direct bond, an aromatic ring or an aromatic heterocycle; X-form O, S, or NR ^a ; and R ^a is a hydrogen atom, a C ₁ to C ₇ aliphatic hydrocarbon, An aromatic ring or an aromatic heterocyclic ring; however, the case where both R ⁵ and R ^{6 are} simultaneously hydrogen is excluded.

Further, the compound of Formula 4 also includes a compound of the following Formula 6.

In Formula 6, Z is O, S, or NR ^b ; and R ⁸ and R ^b are hydrogen, a C ₁ to C ₂₄ alkyl group, a substituted aromatic ring, which includes a C ₅ to C ₂₀ aromatic group. a ring or a hetero atom, a halogen, or an alkyl group or a hetero atom may be bonded to a benzazole ring to form a fused ring of one alkyl group; when n is 2 or more, B is an alkyl group, An arylene group, a substituted alkylene group, or a substituted arylene group, which is conjugated or non-conjugated to a benzoxazole ring as a linking unit, and when n is 1, the B system is substituted or not Substituted alkyl or aryl; and n is an integer from 1 to 8.

For example, an imidazole compound having the following structure can be used:

Examples of the compound having a quinolyl group include compounds represented by the following Chemical Formulas 7 to 13.

In Formulas 7 to 13, n is an integer from 0 to 9, and m is an integer of 2 or more, and R ⁹ is selected from the group consisting of: a cyclic structure having hydrogen; an alkyl group such as a methyl group and an ethyl group. a cycloalkyl group such as a cyclohexyl group and a norbornyl group; an aralkyl group such as a benzyl group; an alkenyl group such as a vinyl group and an allyl group; a cycloalkenyl group such as a cyclopentadienyl group and a cyclohexenyl group; an alkoxy group such as a methoxy group; an alkylthio group; Wherein the oxygen atom of the ether bond of the alkoxy group is substituted by a sulfur atom; an aryl ether group such as a phenoxy group; an aryl thioether group, wherein the aryl ether The oxygen atom of the ether bond is substituted by a sulfur atom; an aryl group such as a phenyl group, a naphthyl group, and a biphenyl group; a heterocyclic group such as Furyl group, thienyl group, oxazolyl group, pryridyl group, quinolyl group, And carbazolyl group; halogen; cyano group; aldehyde group; carbonyl group; carboxyl group; ester group; carbamate Group); amino group; nitro group; silyl group, such as trimethylsilyl group; siloxanyl group, which is ether-bonded a group having an anthracene; and an adjacent substituent; and the substituent may be substituted or unsubstituted, and when n is 2, the substituents may be the same or different from each other; and the Y system is one or two Or an R ⁹ group of the above group.

The compounds of Chemical Formulas 7 to 13 have been described in Korean Patent Application Publication No. 2007-0118711, the entire contents of which are hereby incorporated by reference.

The compound having a phenanthroline group includes a compound of the following formulas 14 to 24, but is not limited thereto.

[Formula 14]

In Formulas 14 to 17, m is an integer of 1 or more, n and p are integers, and n+p is 8 or less, and when m is 1, R ¹⁰ and R ¹¹ are selected from: a ring having hydrogen Structure; alkyl such as methyl and ethyl; cycloalkyl such as cyclohexyl and norbornyl; aralkyl group, such as benzyl group; alkenyl, such as vinyl group And allyl groups; cycloalkenyl groups such as cyclopentadienyl groups and cyclohexenyl groups; alkoxy groups such as methoxy groups; An alkylthio group in which an oxygen atom of an ether bond of an alkoxy group is substituted with a sulfur atom; an aryl ether group such as a phenoxy group; an aryl sulfide group ( Aryl thioether group), wherein the oxygen atom of the ether bond of the aryl ether group is substituted by a sulfur atom; an aryl group such as a phenyl group, a naphthyl group, and a biphenyl group; A heterocyclic group, such as a furyl group, a thiryl group, an oxazolyl group, a pryridyl group, a quinolyl group (q) Uinolyl group), and carbazolyl group; halogen; cyano group; aldehyde group; carbonyl group; carboxyl group; ester group; Carbamoyl group; amino group; nitro group; silyl group, such as trimethylsilyl group; siloxanyl group, a group having an anthracene through an ether bond; and an adjacent substituent; when m is 2 or more, R ¹⁰ is a direct bond or a divalent or higher group, and when m is 1 R ¹¹ is the same, the substituent may be substituted or unsubstituted, and when n or p is 2 or more, the substituents may be the same or different from each other.

The compounds of Chemical Formulas 14 to 17 have been described in Korean Patent Application The disclosures of which are incorporated herein by reference.

[Formula 20]

In the formulae 18 to 21, R ^1a to R ^8a and R ^1b to R ^10b are each a hydrogen atom, a substituted or unsubstituted aryl group having 5 to 60 nuclear atoms, a substituted or unsubstituted pyridine. Pyridyl group, a substituted or unsubstituted quinolyl group, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted group having 3 to 50 a cycloalkyl group of one carbon atom, a substituted or unsubstituted aralkyl group having 6 to 50 nuclear atoms, a substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, a substituted or unsubstituted aryloxy group having 5 to 50 nuclear atoms, a substituted or unsubstituted arylthio group having 5 to 50 nuclear atoms, once substituted or not Substituting an alkoxycarbonyl group having 1 to 50 carbon atoms, an amino group substituted by a substituted or unsubstituted aryl group having 5 to 50 nuclear atoms, a halogen atom, a cyano group, a mononitro group, a monohydroxy group, or a monocarboxy group, and may be bonded to each other to form a a family ring, and L is a substituted or unsubstituted arylene group having 6 to 60 carbon atoms, a substituted or unsubstituted pyridinylene group, a substituted or unsubstituted quinoxaline A quinolynylene group, or a substituted or unsubstituted fluorenylene group. The compounds of the formulae 18 to 21 have been described in Japanese Patent Application Publication No. 2007-39405, the entire contents of which are hereby incorporated by reference.

In Chemical Formulas 22 and 23, d ¹ , d ³ to d ¹⁰ and g ¹ are each hydrogen or an aromatic or aliphatic hydrocarbon group, m and n are integers of 0 to 2, and p is an integer of 0 to 3. The compounds of the formulae 22 and 23 are described in U.S. Patent Publication No. 2007/0122656, the disclosure of which is incorporated herein in its entirety by reference.

In the formula 24, R ^1c to R ^6c are each a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a substituted or An unsubstituted heterocyclic group or a halogen atom, and each of Ar ^1c and Ar ^2c is selected from the following structural formulae.

In the above formula, R ₁₇ to R ₂₃ are each a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, and a substituted one. Or an unsubstituted heterocyclic group or a halogen atom. The compound of the formula 24 has been described in Japanese Patent Application Publication No. 2004-107263, the entire contents of which are hereby incorporated by reference.

cathode

In the present invention, the cathode material may be selected from materials having various work functions. The cathode material is preferably a material having a small work function to facilitate electron injection. However, in the present invention, a material having a large work function can also be used. Specifically, in the present invention, as the cathode material, a material having a work function equal to or greater than the HOMO energy level of the p-type organic material layer as described above can be used. For example, in the present invention, a material having a work function of 2 eV to 5 eV can be used as a cathode material. The cathode material comprises: a metal such as magnesium, calcium, sodium, potassium, titanium, indium, lanthanum, lithium, lanthanum, aluminum, silver, tin, and lead, or an alloy thereof; a multilayer structural material such as LiF/Al or LiO ₂ /Al and the like.

The cathode can be formed using the same material as the anode. Additionally, the cathode or anode can comprise a transparent material.

In the present invention, the anode may be opaque, and the first cathode and the second cathode may be transparent. At this time, the anode includes a metal, and the cathode may have a thickness of 50 nm to 200 nm. Further, the first cathode and the second cathode each independently comprise a metal or a metal oxide, and may each independently have a thickness of 5 nm to 200 nm.

Further, in the present invention, the anode, the first cathode, and the second cathode may both be opaque. Here, the anode, the first cathode, and the second cathode each independently comprise a metal or a metal oxide, and may each independently have a thickness of 5 nm to 200 nm.

In the present invention, the first light emitting unit may further include a third light emitting layer. Here, the organic material layer as shown in Formula 1 may further be included between the first light emitting layer and the third light emitting layer.

Further, in the present invention, the second light emitting unit may further include a fourth light emitting layer. Here, the organic material layer as shown in Formula 1 may further be included between the second light emitting layer and the fourth light emitting layer.

In an organic light emitting device according to an exemplary embodiment of the present invention, the organic light emitting device further includes the third light emitting layer and the fourth The luminescent layer is shown in the schematic diagram of FIG.

In the present invention, the first luminescent layer, the second luminescent layer, the third luminescent layer and the fourth luminescent layer may emit light having the same or different colors.

In particular, the organic light-emitting device according to the present invention has a structure in which the first light-emitting unit and the second light-emitting unit are symmetrical to each other with respect to the anode.

Meanwhile, in the organic light-emitting device, a method of controlling the cavity of the device according to the color of the light can be utilized as one of methods for improving the light-emitting efficiency. The luminous efficiency can be further transmitted through the resonant cavity of the control device to enhance its application to the wavelength of the luminescent color. Here, the resonant cavity of the device means the length of light that can be resonated in the device.

As described above, when the related art organic light-emitting device is as shown in Fig. 1, it includes two light-emitting layers whose cavity lengths are different from each other, thus causing a problem that it is difficult to achieve a desired color.

However, the present invention has a feature that, in the structures of FIGS. 1 and 2, the lengths of the cavities can be controlled to be identical to each other by including an anode as an intermediate electrode and connecting two parallel light-emitting units, and thus can be realized. The desired color.

Hereinafter, specific examples of the above exemplary embodiments will be described in detail. However, the following examples are for illustrative purposes only and are not intended to limit the scope of the exemplary embodiments of the invention.

<Example 1>

Forming a 1,500 Å IZO on a substrate It is the first cathode. Next, on top of this, an electron transporting layer having a thickness of 50 Å is formed by doping an electron transporting material of the following formula with 10% by weight of Ca, and then an electron transporting material of the following formula is used to form an organic material layer having a thickness of 250 Å. .

Above it, a BCP of the following formula is used to form a hole barrier layer having a thickness of 75 Å. Next, a CBP of the following formula was doped with 20 wt% of Ir(ppy) _{3 of the} following formula to form an organic material layer having a thickness of 300 Å.

Above it, a NPB of the following formula is vacuum deposited to form a p-type hole transport layer having a thickness of 300 Å, and then a HAT of the following formula is thermally deposited thereon to form an n-type hole transport layer having a thickness of 300 Å. Thereby, the first light-emitting portion is produced.

Next, a common electrode is formed using Al, and has a thickness of 700 Å.

Subsequently, HAT was deposited as an n-type hole injection layer with a thickness of 300 Å; and NPB was used as a p-type hole transport layer with a thickness of 300 Å.

A light-emitting layer having a thickness of 300 Å was formed by doping CBP of the following formula with 10 wt% of Ir(ppy) _{3 of the} following formula.

Subsequently, BCP was used as a hole barrier layer having a thickness of 50 Å, and an electron transporting material of the following formula was used to form an organic material layer having a thickness of 250 Å. Subsequently, an electron injecting layer was formed by doping an electron transporting material of the following formula with 10% by weight of Ca, thereby producing a second light emitting portion.

Finally, by forming Ag as the second cathode, the thickness is 100Å to produce a pair of light-emitting organic light-emitting devices.

The quantum efficiency (@10 mA/cm ² ) of the device produced, the efficiency of the surface of the electrode of the first cathode is 15%, and the efficiency of the surface of the electrode of the second cathode is 12%, and the two surfaces thereof High light efficiency is achieved. The difference in efficiency between the light emitted on the two surfaces is approximately 1.25:1. At this time, the driving voltage of the device was measured to be 8.5V.

[Electronic Transmission Materials] [BCP]

<Example 2>

A double-emitting organic light-emitting device was fabricated in the same manner as in Example 1, except that the electrode as the intermediate common electrode was composed of Ag and had a thickness of 100 Å as a transparent electrode.

The quantum efficiency (@10 mA/cm ² ) of the device produced was such that the efficiency of the surface of the electrode of the first cathode was 9%, and the efficiency of the surface of the electrode of the second cathode was 7%. The efficiency of light on both surfaces is about 1.3:1. At this time, the driving voltage of the device was measured to be 8.5V.

<Comparative Example 1>

A double-emitting type organic light-emitting device was obtained in the same manner as in Example 1, except that the HAT layer which was in contact with the common electrode as the intermediate electrode in the top and bottom directions was not formed. In the device produced, the hole could not be smoothly injected from the Al as the anode to the NPB as the hole transport layer, so that the normal light-emitting operation could not be performed.

<Comparative Example 2>

On a substrate, an IZO having a thickness of 1,500 Å was formed as a cathode.

Next, HAT is deposited as an n-type hole injection layer, which is thick The degree is 300 Å; and NPB is used as the p-type hole transport layer, and its thickness is 300 Å.

The light-emitting layer was formed to have a thickness of 300 Å by doping CBP with 10 weight percent of Ir(ppy) ₃ of the above formula.

Next, BCP was used to form a hole barrier layer having a thickness of 50 Å, and an organic material layer having a thickness of 250 Å was formed using the electron transport material of the above formula. Subsequently, an electron injecting layer was formed by doping an electron transporting material of the above formula with 10% by weight of Ca, thereby producing a second light emitting portion.

Finally, a pair of light-emitting organic light-emitting devices was produced by forming Ag as a second cathode and having a thickness of 100 Å. The quantum efficiency (@10 mA/cm ² ) of the device produced was such that the efficiency of the surface of the electrode of the first cathode was 9%, and the efficiency of the surface of the electrode of the second cathode was 3%. The light efficiency ratio on both surfaces is approximately 3:1.

As shown in the above results, the organic light-emitting device according to the present invention is applied to a two-emission type organic light-emitting device by symmetrically connecting two light-emitting units to above and below the anode (which is a common electrode). Further, according to the organic light-emitting device of the present invention, the electrode material including the compound represented by Formula 1 is included in the organic material layer, and thus an electrode material having various work functions can be used.

Claims (13)

An organic light-emitting device comprising: a first cathode; a second cathode; and an anode disposed between the first cathode and the second cathode, wherein a first light-emitting unit is disposed at the first Between the cathode and the anode, a second light emitting unit is disposed between the second cathode and the anode, and the first light emitting unit and the second light emitting unit are connected in parallel with each other, and the first light emitting unit includes a first a light-emitting layer, and an organic material layer including a compound represented by the following formula 1 is disposed between the first light-emitting layer and the anode, and the second light-emitting unit includes a second light-emitting layer, and includes the following formula An organic material layer of one of the compounds shown in FIG. 1 is disposed between the second light-emitting layer and the anode, wherein the organic material layers including the compound of Formula 1 are respectively in contact with both sides of the anode, and The first cathode and the second cathode each independently have a thickness of 5 nm to 200 nm: In Formula 1, R ¹ to R ⁶ are the same or different from each other, and are each independently hydrogen, a halogen atom, a nitrile group (-CN), a nitro group (-NO ₂ ), a sulfonyl group (-SO ₂ R), Athene (-SOR), sulfonamide (-SO ₂ NR), sulfonate (-SO ₃ R), trifluoromethyl (-CF ₃ ), ester (-COOR), guanamine (-CONHR) Or -CONRR'), a substituted or unsubstituted linear or branched C ₁ to C ₁₂ alkoxy group, a substituted or unsubstituted linear or branched C ₁ to C ₁₂ alkyl group, once substituted Or unsubstituted linear or branched C ₂ to C ₁₂ alkenyl, substituted or unsubstituted aromatic or non-aromatic heterocyclic ring, substituted or unsubstituted aryl group, substituted or unsubstituted a substituted mono- or diarylamine, or a substituted or unsubstituted arylalkylamine, wherein each of R and R' is a substituted or unsubstituted C ₁ to C ₆₀ alkyl group, once substituted or not Substituted aryl, or substituted or unsubstituted 5- to 7-membered heterocyclic ring. The organic light-emitting device of claim 1, wherein the organic light-emitting device is a double-emission type. The organic light-emitting device of claim 1, wherein the anode is opaque, and the first cathode and the second cathode are transparent. The organic light-emitting device of claim 3, wherein the anode comprises a metal and has a thickness of 50 nm to 200 nm. The organic light-emitting device of claim 3, wherein the first cathode and the second cathode each independently comprise a metal or a metal oxide. The organic light-emitting device of claim 1, wherein the anode, the first cathode, and the second cathode are all transparent. The organic light-emitting device of claim 6, wherein the anode comprises a metal or a metal oxide and has a thickness of 5 nm to 200 nm. The organic light-emitting device of claim 1, wherein the first light-emitting unit further comprises a third light-emitting layer. The organic light-emitting device of claim 8, further comprising: the organic material layer of the compound of formula 1 disposed between the first light-emitting layer and the third light-emitting layer. The organic light-emitting device of claim 1, wherein the second light-emitting unit further comprises a fourth light-emitting layer. The organic light-emitting device of claim 10, further comprising: the organic material layer of the compound of formula 1 disposed between the second light-emitting layer and the fourth light-emitting layer. The organic light-emitting device of claim 1, wherein the first light-emitting layer and the second light-emitting layer have the same or different colors. The organic light-emitting device of claim 1, wherein the organic light-emitting device has a structure, wherein the first light-emitting unit and the second light-emitting unit are symmetric with each other with respect to the anode.