KR101108156B1 - White organic light emitting device - Google Patents

Abstract

A white organic light emitting device is disclosed. The disclosed white organic light emitting device comprises a first light emitting layer comprising a first hole transporting host material, a second light emitting layer comprising a second hole transporting host material, or a first light emitting layer comprising a first hole transporting host material and a second The light emitting layer comprises a second hole transport host material.

Description

White organic light emitting device

A white organic light emitting device is provided. The white organic light emitting device has improved white balance characteristics and excellent luminous efficiency by adjusting the type and content of the host material of the light emitting layer.

Organic Light Emitting Device (OLED) is an active light emitting device in which holes supplied from an anode and electrons supplied from a cathode are combined in an organic light emitting layer formed between the anode and the cathode to emit light. It is a light emitting element. Such an organic light emitting device is capable of driving a low voltage, it is possible to implement a high luminance surface emission, has a very fast response speed, there is an advantage that can be manufactured in a thin thickness. Furthermore, due to its excellent color reproducibility, fast response speed, spontaneous emission, thin thickness, high contrast ratio, wide viewing angle and low power consumption, it can be used not only for TV, PC monitor, mobile communication terminal, MP3 player and car navigation, but also for indoor and outdoor. It can also be widely used as lighting or signage.

The driving principle of the organic light emitting device is as follows.

When a voltage is applied between the anode and the cathode, holes injected from the anode move to the light emitting layer via the hole transport layer, and electrons injected from the cathode move to the light emitting layer via the electron transport layer. Carriers such as holes and electrons recombine in the emission layer to generate excitons, and light is generated as the excitons change from an excited state to a ground state.

Recently, development of organic light emitting diodes for displays has been actively conducted, and particularly, development of white light emitting diodes has been actively performed. The white organic light emitting diode is an organic light emitting diode that emits white light, and can be used for a thin light source, a backlight of a liquid crystal display, or a full color display employing a color filter.

The white organic light emitting device has a structure in which light emitting layers having a predetermined color are stacked therein, and since the materials constituting the light emitting layers of each color are different from each other, it is difficult to realize stable colors when the injected current changes. In addition, since the white organic light emitting device emits light from the light emitting layer of each color, the luminous efficiency is lower than that of the organic light emitting device having a single light emitting layer. In particular, in the case of the white organic light emitting device having the blue, green, and red light emitting layers, the red light emitting layer is excellent in light emitting efficiency, but the remaining green and blue light emitting layers do not obtain satisfactory light emitting efficiency.

It is to provide a white organic light emitting device having improved luminous efficiency.

In order to achieve the above technical problem, according to an aspect of the present invention,

Board; A first electrode; A second electrode facing the first electrode; An organic layer interposed between the first electrode and the second electrode,

The first electrode is a hole injection electrode and the second electrode is an electron injection electrode,

The organic layer has a structure laminated in the order of the first light emitting layer, the second light emitting layer and the third light emitting layer from the first electrode side,

a) the first light emitting layer comprises a first hole transport host material

b) the second light emitting layer comprises a second hole transport host material or

c) A white organic light emitting device is provided wherein the first light emitting layer comprises a first hole transporting host material and the second light emitting layer comprises a second hole transporting host material.

The first light emitting layer may include a first hole transporting host material and the second light emitting layer may include a second hole transporting host material.

The first light emitting layer may further include a first electron transporting host material, the second light emitting layer may further include a second electron transporting host material, and the third light emitting layer may include a third electron transporting host material.

The first light emitting layer may be a blue light emitting layer, the second light emitting layer may be a green light emitting layer, and the third light emitting layer may be a red light emitting layer.

The first hole transporting host material and the second hole transporting host material are independently of each other N, N'-bis (1-naphthyl) -N, N'-bis (phenyl) benzidine (NPB), 4,4 ' , 4′-tris (N-carbazolyl) triphenylamine (TCTA) and 4,4′-bis (carbazol-9-yl) biphenyl (CBP).

The first electron transporting host material, the second electron transporting host material, and the third electron transporting host material are independently of each other 9,10-di (naph-2-tyl) anthracene (ADN), tris (8-hydroxyquinoline) Aluminum (Alq3), 10-benzo [h] quinolinol-beryllium complex (Bebq2), ZnPBO, and bis- (2-methyl-8-quinolinolate) -4- (phenylphenolrato) -aluminum (BAlq It may be one or more selected from the group consisting of.

The first light emitting layer includes 20 to 150 parts by weight of the first hole transporting host material per 100 parts by weight of the first electron transporting host material, and the second light emitting layer comprises the second hole per 100 parts by weight of the second electron transporting host material. And 20 to 150 parts by weight of the transportable host material.

The first hole transporting host material may be NPB, and the second hole transporting host material may be TCTA.

The first electron transport host may be a fluorescent host and the second electron transport host and the third electron transport host may be phosphorescent hosts.

In the white organic light emitting diode, a light emitting zone spreads over an entire region of the light emitting layer and white balance is improved.

Hereinafter, a white organic light emitting diode according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals refer to the same components, and it should be noted that the size of each component may be exaggerated for explanation.

1 schematically illustrates a cross-sectional view of a white organic light emitting diode 100 according to an embodiment of the present invention.

Referring to FIG. 1, the white organic light emitting diode 100 may include a substrate 110; First electrode 120; A second electrode 130 facing the first electrode; The organic layer 140 is interposed between the first electrode and the second electrode, and the organic layer 140 includes the first light emitting layer 141, the second light emitting layer 143, and the third light emitting layer 145 from the first electrode side. Laminated in order). The electron transport layer 160 may be formed between the first electrode 120 and the first light emitting layer 141 or between the third light emitting layer 145 and the second electrode 130, but may be omitted. . The first electrode 120 is a hole injection electrode and the second electrode 130 is an electron injection electrode.

In one embodiment of the present invention, the white organic light emitting device 100 includes a substrate 110; First electrode 120; A second electrode 130 facing the first electrode; An organic layer 140 interposed between the first electrode and the second electrode, wherein the first electrode is a hole injection electrode, the second electrode is an electron injection electrode, and the organic layer is a first electrode from the first electrode side. The light emitting layer 141, the second light emitting layer 143, and the third light emitting layer 145 are stacked in the order of: a) the first light emitting layer 141 includes a first hole transporting host material; b) the second light emitting layer 143 comprises a second hole transport host material; Alternatively, c) the first light emitting layer 141 may include a first hole transporting host material, and the second light emitting layer 143 may include a second hole transporting host material.

As the substrate 110, a glass substrate, a quartz substrate, or a plastic substrate used in a conventional organic light emitting device may be used. A glass substrate or transparent plastic having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and waterproofness may be used. Substrates can be used.

The first electrode 120 may be formed by providing a material for the first electrode on the substrate 110 by a deposition method or a sputtering method. The first electrode 120 may be a reflective electrode or a transmissive electrode. The first electrode 120 is a hole injection electrode that injects holes. Therefore, the first electrode 120 may be formed of a material having high conductivity and work function to facilitate hole injection. Specifically, the material for the first electrode may be selected from materials having a work function of about 4.7 eV or more. As the material for the first electrode, for example, transparent indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO 2), zinc oxide (ZnO), or the like may be used. The first electrode 120 includes magnesium (Mg), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), or the like. It may be used to form a reflective electrode. The first electrode 120 may be made of a metal having a low work function. For example, it may be made of a metal such as aluminum (Al), silver (Ag), magnesium (Mg), lithium (Li) or calcium (Ca), or an alloy thereof. But it is not limited thereto.

The organic layer 140 may be formed on the first electrode 120 by using a vacuum deposition method, a spin coating method, a cast method, an LB method, or the like.

The organic layer 140 may be laminated with one or more light emitting layers to emit white light, and may optionally include any one or more of a hole transport layer 150 and an electron transport layer 160.

First, the hole transport layer 150 may be selectively formed on the first electrode by using various methods such as vacuum deposition, spin coating, casting, and LB. When the hole transport layer 150 is formed by vacuum deposition, deposition conditions vary depending on the compound used as the material of the hole transport layer, the structure and thermal properties of the desired hole transport layer, and the deposition temperature is generally 100 to 500 ° C. and vacuum degree 10. ^It can select suitably from ^-8 to 10 ^-3 torr and a deposition rate of 0.01 to 100 mW / sec.

When the hole transport layer 150 is formed by spin coating, coating conditions vary depending on the compound used as the material of the hole transport layer, the structure and thermal properties of the desired hole transport layer, and a coating speed of about 2000 to 5000 rpm, The heat treatment temperature for solvent removal after coating may be appropriately selected in the range of about 80 to 200 ° C.

The hole transport layer material can be formed using a known hole transport material, for example, carbazole derivatives such as N-phenylcarbazole, polyvinylcarbazole, N, N'-bis (3-methylphenyl) -N , N'-diphenyl- [1,1-biphenyl] -4,4'-diamine (TPD), N, N'-di (naphthalen-1-yl) -N, N'-diphenyl benzidine (α Amine derivatives having an aromatic condensed ring such as -NPD), and triphenylamine-based materials such as TCTA (4,4 ', 4'-tris (N-carbazolyl) triphenylamine). In the case of TCTA, in addition to the hole transport role, it may also play a role of preventing the diffusion of excitons from the light emitting layer described later.

The hole transport layer 150 may have a thickness of about 50 to 1000 mm 3, for example, 100 to 800 mm 3. When the thickness of the hole transport layer satisfies this range, a satisfactory level of hole transport characteristics can be obtained without a substantial increase in driving voltage.

A first light emitting layer 141 is formed on the hole transport layer 150, a second light emitting layer 143 is formed on the first light emitting layer 141, and a first light emitting layer 143 is formed on the second light emitting layer 143. Three light emitting layers 145 may be formed.

The first light emitting layer 141 may include a first hole transporting host material, the second light emitting layer 143 may include a second hole transporting host material, or the first light emitting layer 141 may be a first hole transporting host material. It may include a material and the second light emitting layer 143 may include a second hole transport host material.

Since the first light emitting layer 141 is adjacent to or close to the first electrode 120 which is the hole injection electrode, the characteristics of the light emitting layer are stronger than other light emitting layers. The third light emitting layer 145 far from the first electrode 120 has no problem in light emitting efficiency, but the first light emitting layer 141 located near the first electrode 120 may not obtain satisfactory light emitting efficiency. For example, in the case where the first light emitting layer 141, the second light emitting layer 143, and the third light emitting layer 145 are blue, green, and red light emitting layers, red is excellent in luminous efficiency but blue is inferior in luminous efficiency. In order to correct this phenomenon and maintain white balance, the light emitting area should be widely spread over the light emitting layer. To this end, the first light emitting layer 141 may include a first hole transporting host material having better hole transfer characteristics than electron transfer characteristics, which may smoothly transfer holes toward the third light emitting layer 143.

The first hole transporting host material is N, N′-bis (1-naphthyl) -N, N′-bis (phenyl) benzidine (NPB), 4,4 ′, 4′-tris (N-carbazolyl) tree Phenylamine (TCTA) and 4,4′-bis (carbazol-9-yl) biphenyl (CBP). However, it is not limited thereto. The first light emitting layer 141 may be formed to a thickness of about 1 to 20nm.

The second light emitting layer 143 may include a second hole transport host material. Like the first light emitting layer 141, the second light emitting layer 143 is close to the first electrode 120, and thus exhibits strong light emitting layer characteristics. Therefore, the second light emitting layer 143 has better hole transfer characteristics than electron transfer characteristics in order to spread the light emitting region widely. It may include a host material that can be delivered to the third light emitting layer 145 smoothly.

The second hole transporting host material is N, N′-bis (1-naphthyl) -N, N′-bis (phenyl) benzidine (NPB), 4,4 ′, 4′-tris (N-carbazolyl) tree Phenylamine (TCTA) and 4,4′-bis (carbazol-9-yl) biphenyl (CBP). But it is not limited thereto. The second light emitting layer 143 may be formed to a thickness of about 1 to 20nm.

The third light emitting layer 145 uses a portion of electrons injected from the second electrode 130 to emit light, and the remaining electrons are transferred to the first light emitting layer 141 and the second light emitting layer by a phosphorescent host material having excellent electron transfer characteristics. 143). The third light emitting layer 145 may be formed to a thickness of about 1 to 20nm.

In one embodiment of the present invention, the first light emitting layer 141 further includes a first electron transporting host material, the second light emitting layer 143 further includes a second electron transporting host material, and the third light emitting layer 145 may comprise a third electron transport host material.

The first electron transporting host material, the second electron transporting host material and the third electron transporting host material are independently 9,10-di (naph-2-tyl) anthracene (AND), tris (8-hydroxyquinoline) aluminum (Alq3), 10-benzo [h] quinolinol-beryllium complex (Bebq2), ZnPBO, and bis- (2-methyl-8-quinolinolate) -4- (phenylphenolrato) -aluminum (BAlq) It may be selected from the group consisting of. But it is not limited thereto.

Since the first light emitting layer 141 and the second light emitting layer 143 include fluorescent host materials having excellent hole transport characteristics and electron transport characteristics, and the third light emitting layer 145 includes phosphorescent host materials having excellent electron transfer characteristics, The light emitting region of the first light emitting layer 141 may be further moved toward the third light emitting layer 145 so that the light emitting zone may be spread throughout the light emitting layer, and as a result, the white balance may be further improved.

In one embodiment of the present invention, the first light emitting layer comprises 20 to 150 parts by weight, for example 30 to 100 parts by weight, of the first hole transporting host material per 100 parts by weight of the first electron transporting host material, and the second The emission layer may include 20 to 150 parts by weight, for example, 30 to 100 parts by weight, of the second hole transporting host material per 100 parts by weight of the second electron transporting host material. When the layer contains less than 20 parts by weight of the hole transporting host material, the electron transporting capacity may be deteriorated when the layer does not have the hole transporting capacity properly and includes more than 150 parts by weight of the hole transporting host material.

In the white organic light emitting device including the electron transporting host material and the hole transporting host material within the above range, the first light emitting layer adjacent to the first electrode or the hole transporting layer has a strong hole transporting property, and the second light emitting layer has an original property. The third light emitting layer adjacent to the two electrodes or the electron transporting layer has electron transporting properties. The second light emitting layer may optionally have strong hole transport characteristics.

In one embodiment of the present invention, the first electron transporting host material may be a fluorescent host material and the second electron transporting host material and the third electron transporting host material may be phosphorescent host materials. But it is not limited thereto.

In one embodiment of the present invention, the first light emitting layer 141 may be a blue light emitting layer, the second light emitting layer 143 may be a green light emitting layer, and the third light emitting layer 145 may be a red light emitting layer.

The first light emitting layer 141 may be a blue light emitting layer emitting blue light. The first light emitting layer 141 may be formed by using, for example, a blue dopant in a predetermined host material. As a blue dopant, F2Irpic, (F2ppy) 2Ir (tmd), Ir (dfppz) 3, ter-fluorene, 4,4'-bis (4-diphenylaminostaryl) biphenyl (DPAVBi), 2,5, 8,11-tetra-ti-butyl perylene (TBPe) and the like can be used, but is not limited thereto.

DPAVBi TBPe

The second light emitting layer 143 may be a green light emitting layer emitting green light. The second light emitting layer 143 may be formed by using, for example, a green dopant in a predetermined host material. As green dopant, Ir (ppy) 3 (ppy = phenylpyridine), Ir (ppy) 2 (acac), Ir (mpyp) 3, C545T (10- (2-benzothiazolyl) -2,3,6,7 Tetrahydro-1,1,7,7-tetramethyl-1H, 5H, 11H- (1) -benzopyrano (6,7,8-ij) quinolizine-11-one) It is not limited to this.

The third light emitting layer 145 may be, for example, a red light emitting layer emitting red light. The third light emitting layer 145 may be formed by using, for example, a red dopant in a predetermined host material. PtOEP, Ir (piq) 3, Btp2Ir (acac), DCJTB (4- (dicyanomethylene) -2-tert-butyl-6- (1,1,7,7-tetramethyleurolidine-4 as red dopant -Yl-vinyl) -4H-pyran) and the like, but is not limited thereto.

When the dopant and the host are used together, the doping concentration of the dopant is not particularly limited but is usually 0.01 to 15 parts by weight based on 100 parts by weight of the host.

The thickness of the light emitting layer may be about 100 to 1000 kPa, for example, 200 to 600 kPa. When the thickness of the light emitting layer satisfies the aforementioned range, the light emitting layer may exhibit excellent light emission characteristics without substantially increasing the driving voltage.

The electron transport layer 160 is formed on the third light emitting layer 145 using various methods such as vacuum deposition, spin coating, and casting. When the electron transport layer 160 is formed by vacuum deposition, deposition conditions vary depending on the compound used as the material of the electron transport layer, the structure and thermal properties of the desired electron transport layer, and the deposition temperature is generally 100 to 500 ° C. and vacuum degree 10. ^It can select suitably from ^-8 to 10 ^-3 torr and a deposition rate of 0.01 to 100 mW / sec.

When the electron transport layer 160 is formed by spin coating, coating conditions vary depending on the compound used as the material of the electron transport layer, the structure and thermal properties of the desired electron transport layer, and a coating speed of about 2000 to 5000 rpm, The heat treatment temperature for solvent removal after coating may be appropriately selected in the range of about 80 to 200 ° C.

As the electron transporting material, the electron transporting material can be used as a function of stably transporting the electrons injected from the second electrode. Examples thereof may include, but are not limited to, quinoline derivatives, in particular tris (8-quinolinorate) aluminum (Alq 3), TAZ, Balq, and the like.

TAZ

The thickness of the electron transport layer may be about 100 to 1000 kPa, for example 150 to 500 kPa. When the thickness of the electron transporting layer satisfies the above-described range, satisfactory electron transporting characteristics can be obtained without a substantial increase in driving voltage.

Although not shown in the drawing, a hole suppression layer may be formed between the third light emitting layer 145 and the electron transport layer 160 as necessary.

The hole suppression layer may be formed on the third light emitting layer 145 by using various methods such as vacuum deposition, spin coating, casting, and LB before the electron transport layer 160 is formed.

In the case of forming the hole suppression layer by the vacuum deposition method, the deposition conditions vary depending on the compound used as the material of the hole suppression layer, the structure and thermal properties of the desired hole suppression layer, and the like. ^It can select suitably from ^-8 to 10 ^-3 torr and a deposition rate of 0.01 to 100 mW / sec.

In the case of forming the hole suppression layer by spin coating, the coating conditions vary depending on the compound used as the material of the hole suppression layer, the structure and thermal properties of the desired hole suppression layer, and generally a coating speed of about 2000 to 5000 rpm, The heat treatment temperature for solvent removal after coating may be appropriately selected in the range of about 80 to 200 ° C.

Examples of the material for the hole suppression layer include oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, and the like.

The hole suppression layer may have a thickness of about 50 to 1000 kPa, for example, 100 to 300 kPa. When the thickness of the hole suppression layer satisfies the above-described range, excellent hole suppression characteristics may be obtained without a substantial increase in driving voltage.

Although not shown in the drawings, a hole injection layer may be formed between the first electrode 120 and the hole transport layer 150 or an electron injection layer may be formed between the electron transport layer 160 and the second electrode 130 as necessary. Can be.

The hole injection layer may be formed on the first electrode 120 using various methods such as vacuum deposition, spin coating, cast, LB, and the like.

When the hole injection layer is formed by vacuum deposition, the deposition conditions vary depending on the compound used as the material of the hole injection layer and the structure and thermal characteristics of the desired hole injection layer. ^It can select suitably in the range of ^-8 to 10 ^-3 torr and a deposition rate of 0.01 to 100 mW / sec.

In the case of forming the hole injection layer by spin coating, the coating conditions are different depending on the structure and thermal properties of the compound used as the hole injection layer material and the desired hole injection layer, but the coating speed of about 2000 to 5000 rpm, the coating It may be appropriately selected in the heat treatment temperature range of about 80 to 200 ℃ for the solvent removal after.

Examples of the hole injection layer material include phthalocyanine compounds such as copper phthalocyanine, m-MTDATA [4,4 ', 4'-tris (3-methylphenylphenylamino) triphenylamine], NPB (N, N'-di ( 1-naphthyl) -N, N'-diphenylbenzidine), TDATA, 2T-NATA, Pani / DBSA (polyaniline / dodecylbenzenesulfonic acid), PEDOT / PSS (poly (3,4-ethylenedioxythiophene) / Poly (4-styrenesulfonate)), Pani / CSA (polyaniline / camphorsulfonic acid) or PANI / PSS ((polyaniline) / poly (4-styrenesulfonate)), and the like, may be used, but is not limited thereto.

The hole injection layer may have a thickness of about 100 to 10000 mm 3, for example, 100 to 1000 mm 3. When the thickness of the hole injection layer satisfies the above range, a satisfactory hole injection characteristic may be obtained without a substantial increase in driving voltage.

An electron injection layer may be stacked on the electron transport layer 160 to facilitate the injection of electrons from the cathode, which does not particularly limit the material.

As the electron injection layer forming material, a material such as LiF, NaCl, CsF, Li 2 O, BaO, or the like may be used. Although the deposition conditions of the electron injection layer are different depending on the compound used, they are generally selected in the same range of conditions as the formation of the hole injection layer.

The electron injection layer may have a thickness of about 1 to 100 kPa, for example, 5 to 90 kPa. When the thickness of the electron injection layer satisfies this range, satisfactory electron injection characteristics may be obtained without a substantial increase in driving voltage.

The second electrode 130 is provided on the organic layer 140. As the metal for forming the second electrode, a metal, an alloy, an electrically conductive compound having a low work function, and a mixture thereof may be used. Specific examples include lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), and the like. It can be formed into a thin film to obtain an electrode. On the other hand, various modifications are possible, such as to form a transmissive electrode using ITO, IZO to obtain a top light emitting device.

Hereinafter, the production method of the present invention will be described in more detail with reference to Examples. However, this is only to illustrate the manufacturing method of the present invention as a matter of course that the scope of the present invention is not limited by this embodiment.

Example 1

As an anode on the top of the substrate, Corning's 15Ω / ㎠ (1200Å) ITO glass substrate was cut into 50mm ㅧ 50mm 크기 0.7mm and ultrasonically cleaned for 5 minutes in isopropyl alcohol and pure water, followed by UV ozone cleaning for 30 minutes. It was. A-NPD was vacuum deposited on the anode to form a hole transport layer having a thickness of 150 kHz.

ADN as a first electron transporting host material, NPB as a first hole transporting host material, and F2Irpic as a blue dopant were co-deposited at a weight ratio of 1: 1: 0.1 to form a first light emitting layer having a thickness of 10 nm on the hole transporting layer.

Alq3 and green dopant Ir (ppy) 3 are co-deposited at a weight ratio of 1: 0.1 as a second electron transporting host material on the first light emitting layer to form a second light emitting layer having a thickness of 10 nm, and an upper portion of the second light emitting layer. Bebq2 and red dopant Ir (piq) 3 were co-deposited at a weight ratio of 1: 0.05 as a third electron transporting host material to form a third light emitting layer having a thickness of 10 nm.

Alq3 was vacuum deposited on the third light emitting layer to form an electron transport layer having a thickness of 200 μs, and Al was vacuum deposited to form a cathode having a thickness of 3000 μm.

The spectrum of the obtained organic light emitting device using the Spectrometer PR650 is shown in Figure 2 the results.

Example 2

As an anode on the top of the substrate, Corning's 15Ω / ㎠ (1200Å) ITO glass substrate was cut into 50mm ㅧ 50mm 크기 0.7mm and ultrasonically cleaned for 5 minutes in isopropyl alcohol and pure water, followed by UV ozone cleaning for 30 minutes. It was. M-MTDATA was vacuum deposited on the anode to form a hole injection layer having a thickness of 750 mm3. A-NPD was vacuum deposited on the hole injection layer to form a hole transport layer having a thickness of 150 kHz.

ADN as a first electron transporting host material, NPB as a first hole transporting host material, and F2Irpic as a blue dopant were co-deposited at a weight ratio of 2: 1: 0.1 on the hole transport layer to form a first light emitting layer having a thickness of 10 nm.

Alq3 and green dopant Ir (ppy) 3 are co-deposited at a weight ratio of 1: 0.1 as a second electron transporting host material on the first light emitting layer to form a second light emitting layer having a thickness of 10 nm, and an upper portion of the second light emitting layer. Bebq2 and red dopant Ir (piq) 3 were co-deposited at a weight ratio of 1: 0.05 as a third electron transporting host material to form a third light emitting layer having a thickness of 10 nm.

Alq3 was vacuum deposited on the third light emitting layer to form an electron transport layer having a thickness of 200 μs, and Al was vacuum deposited to form a cathode having a thickness of 3000 μm.

The spectrum of the obtained organic light emitting device using the Spectrometer PR650 is shown in Figure 3 the results.

Comparative Example 1

As an anode on the top of the substrate, Corning's 15Ω / ㎠ (1200 I) ITO glass substrate was cut into 50mm ㅧ 50mm 크기 0.7mm and ultrasonically cleaned for 5 minutes in isopropyl alcohol and pure water, followed by UV ozone cleaning for 30 minutes. It was. A-NPD was vacuum deposited on the anode to form a hole transport layer having a thickness of 150 kHz.

ADN and a blue dopant standing F2 Irpic as a first electron transporting host material were co-deposited at a weight ratio of 1: 0.05 on the hole transport layer to form a first light emitting layer having a thickness of 10 nm, and a second electron transporting host on the first light emitting layer. Alq3 as a material and Ir (ppy) 3 as a green dopant are co-deposited at a weight ratio of 1: 0.1 to form a second light emitting layer having a thickness of 10 nm, and Bebq2 as a third electron transporting host material and a red dopant on the second light emitting layer. Ir (piq) 3 was co-deposited at a weight ratio of 1: 0.05 to form a third light emitting layer having a thickness of 10 nm.

Alq3 was vacuum deposited on the third light emitting layer to form an electron transport layer having a thickness of 200 μs, and Al was vacuum deposited to form a cathode having a thickness of 3000 μm.

The spectrum of the obtained organic light emitting device was measured using a Spectrometer PR650.

Example 3

As an anode on the top of the substrate, Corning's 15Ω / ㎠ (1200Å) ITO glass substrate was cut into 50mm ㅧ 50mm 크기 0.7mm and ultrasonically cleaned for 5 minutes in isopropyl alcohol and pure water, followed by UV ozone cleaning for 30 minutes. It was. M-MTDATA was vacuum deposited on the anode to form a hole injection layer having a thickness of 750 mm3. A-NPD was vacuum deposited on the hole injection layer to form a hole transport layer having a thickness of 150 kHz.

ADN as a first electron transporting host material, NPB as a first hole transporting host material, and F2Irpic as a blue dopant in a weight ratio of 1: 1: 0.1 are co-deposited to form a first light emitting layer having a thickness of 10 nm on the hole transporting layer. 10 nm thick second light emitting layer by co-depositing Alq3 as the second electron transporting host material, TCTA and the green dopant Ir (ppy) 3 in the weight ratio of 1: 1: 0.2 on top of the first light emitting layer Formed.

Bebq2 and red dopant Ir (piq) 3 were co-deposited at a weight ratio of 1: 0.05 as a third electron transporting host material on the second emission layer to form a third emission layer having a thickness of 10 nm.

Alq3 was vacuum deposited on the third light emitting layer to form an electron transport layer having a thickness of 200 μs, and Al was vacuum deposited to form a cathode having a thickness of 3000 μm.

The spectrum of the obtained organic light emitting device using the Spectrometer PR650 is shown in Figure 5 the results.

Example 4

As an anode on the top of the substrate, Corning's 15Ω / ㎠ (1200Å) ITO glass substrate was cut into 50mm ㅧ 50mm 크기 0.7mm and ultrasonically cleaned for 5 minutes in isopropyl alcohol and pure water, followed by UV ozone cleaning for 30 minutes. It was. M-MTDATA was vacuum deposited on the anode to form a hole injection layer having a thickness of 750 mm3. A-NPD was vacuum deposited on the hole injection layer to form a hole transport layer having a thickness of 150 kHz.

ADN as a first electron transporting host material, NPB as a first hole transporting host material, and F2Irpic as a blue dopant material are co-deposited at a weight ratio of 3: 1: 0.2 on the hole transport layer to form a first light emitting layer having a thickness of 10 nm. 10 nm thick second light emitting layer by co-depositing Alq3 as a second electron transporting host material, TCTA and a green dopant Ir (ppy) 3 as a 2: 1: 0.4 weight ratio on top of the first light emitting layer Formed.

Bebq2 and a red dopant Ir (piq) 3 were co-deposited at a weight ratio of 1: 0.05 as a third electron transporting host material on the second emission layer to form a third emission layer having a thickness of 10 nm.

Alq3 was vacuum deposited on the third light emitting layer to form an electron transport layer having a thickness of 200 μs, and Al was vacuum deposited to form a cathode having a thickness of 3000 μm.

The spectrum of the obtained organic light emitting device using the Spectrometer PR650 is shown in Figure 6 the results.

Comparative Example 2

As an anode on the top of the substrate, Corning's 15Ω / ㎠ (1200Å) ITO glass substrate was cut into 50mm ㅧ 50mm 크기 0.7mm and ultrasonically cleaned for 5 minutes in isopropyl alcohol and pure water, followed by UV ozone cleaning for 30 minutes. It was. M-MTDATA was vacuum deposited on the anode to form a hole injection layer having a thickness of 750 mm3. A-NPD was vacuum deposited on the hole injection layer to form a hole transport layer having a thickness of 150 kHz.

ADN and a blue dopant F2 Irpic as a first electron transporting host material are co-deposited on the hole transport layer in a weight ratio of 1: 0.05 to form a first light emitting layer having a thickness of 10 nm, and a second electron transporting host on the first light emitting layer. Alq3 as a material and Ir (ppy) 3 as a green dopant are co-deposited at a weight ratio of 1: 0.1 to form a second light emitting layer having a thickness of 10 nm, and Bebq2 as a third electron transporting host material and a red dopant on the second light emitting layer. Ir (piq) 3 was co-deposited at a weight ratio of 1: 0.05 to form a third light emitting layer having a thickness of 10 nm.

Alq3 was vacuum deposited on the third light emitting layer to form an electron transport layer having a thickness of 200 μs, and Al was vacuum deposited to form a cathode having a thickness of 3000 μm.

The spectrum of the obtained organic light emitting device was measured using a Spectrometer PR650. The results are shown in FIG. 7.

From 2 to 4 it can be seen that the white organic light emitting device of Examples 1 and 2 has a reduced specific gravity of the blue peak in the first light emitting layer (blue light emitting layer) compared to the white organic light emitting device of Comparative Example 1.

5 to 7, the white organic light emitting diodes of Examples 3 and 4 may reduce the specific gravity of the green peak in the second light emitting layer (green light emitting layer) compared to the white organic light emitting diode of Comparative Example 2.

1 is a view schematically showing a structure of a white organic light emitting diode according to an embodiment of the present invention.

2 is an EL graph of an organic light emitting device obtained according to Example 1 of the present invention.

3 is an EL graph of an organic light emitting device obtained according to Example 2 of the present invention.

4 is an EL graph of an organic light emitting device obtained according to Comparative Example 1 of the present invention.

5 is an EL graph of an organic light emitting device obtained according to Example 3 of the present invention.

6 is an EL graph of an organic light emitting device obtained according to Example 4 of the present invention.

7 is an EL graph of an organic light emitting device obtained according to Comparative Example 2 of the present invention.

Claims (9)

Board; A first electrode; A second electrode facing the first electrode; An organic layer interposed between the first electrode and the second electrode, The first electrode is a hole injection electrode and the second electrode is an electron injection electrode, The organic layer has a structure laminated in the order of the first light emitting layer, the second light emitting layer and the third light emitting layer from the first electrode side, a) the first light emitting layer comprises a first electron transporting host material and a first hole transporting host material, the second light emitting layer comprises a second electron transporting host material and the third light emitting layer comprises a third electron transporting host material do or; or b) the first light emitting layer comprises a first electron transporting host material and a first hole transporting host material and the second light emitting layer comprises a second electron transporting host material and a second hole transporting host material and the third light emitting layer is formed of A tri-electron transporting host material; White organic light emitting device. delete delete The white organic light emitting diode of claim 1, wherein the first light emitting layer is a blue light emitting layer, the second light emitting layer is a green light emitting layer, and the third light emitting layer is a red light emitting layer. The method of claim 1, wherein the first hole transporting host material and the second hole transporting host material are independently of each other N, N'-bis (1-naphthyl) -N, N'-bis (phenyl) benzidine (NPB ), 4,4 ′, 4′-tris (N-carbazolyl) triphenylamine (TCTA) and 4,4′-bis (carbazol-9-yl) biphenyl (CBP) The white organic light emitting element which is above. The method of claim 1, wherein the first electron transporting host material, the second electron transporting host material and the third electron transporting host material are independently of each other ADN (9,10-di (naph-2- yl) anthracene), tris ( 8-hydroxyquinoline) aluminum (Alq3), 10-benzo [h] quinolinol-beryllium complex (Bebq2), ZnPBO, and bis- (2-methyl-8-quinolinolate) -4- (phenylphenol White organic light emitting device, characterized in that at least one selected from the group consisting of: Raito) -aluminum (BAlq). The method of claim 1, wherein the first light emitting layer comprises 20 to 150 parts by weight of the first hole transporting host material per 100 parts by weight of the first electron transporting host material, and the second light emitting layer comprises the second electron transporting host material 100. A white organic light emitting device comprising 20 to 150 parts by weight of the second hole transporting host material per weight part. The white organic light emitting diode of claim 1, wherein the first hole transporting host material is NPB, and the second hole transporting host material is TCTA. The white organic light emitting device of claim 1, wherein the first electron transporting host material is a fluorescent host material and the second electron transporting host material and the third electron transporting host material are phosphorescent host materials.

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