CN1988203B - Organic luminescence display device and method of manufacturing the same - Google Patents

Abstract

An organic light emitting display device having an emission layer between a first electrode and a second electrode is disclosed. One embodiment of the device includes: a first hole injection layer and a second hole injection layer between the first electrode and the emissive layer; and between the first hole injection layer and the second hole injection layer A charge generation layer doped with a p-type dopant. The device has reduced drive voltage and enhanced efficiency and lifetime.

Description

Organic light emitting display device and manufacturing method thereof

Cross References to Related Applications

This application claims the benefit of Korean Patent Applications No. 10-2005-0126101 filed December 20, 2005 and No. 10-2005-0129922 filed December 26, 2005 at the Korean Intellectual Property Office, which are incorporated herein in their entirety The public content of .

technical field

The present disclosure relates to an organic light emitting display device and a method of manufacturing the same, and more particularly, to an organic light emitting display device having a charge generation layer and a method of manufacturing the same.

Background technique

Electroluminescence (EL) devices are self-emissive display devices that have attracted much attention due to their advantages such as wide viewing angle, high contrast and short response time. EL devices are classified into inorganic EL devices and organic EL devices according to the material used to form the emission layer of the EL device. Organic EL devices have good luminance and driving voltage and short response time. Organic EL devices can also display color images.

Generally, an organic light emitting display device has an anode formed on a substrate. The organic EL device also includes a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL), and a cathode sequentially stacked on the anode. Here, HTL, EML, and ETL include organic thin films formed of organic compounds.

The organic EL device described above works as follows. A voltage is applied between the anode and cathode. Then, holes are injected from the anode to the emissive layer through the hole transport layer. Electrons are injected from the cathode to the emissive layer through the electron transport layer. The electrons and holes recombine with each other in the emission layer, thereby forming excitons having an excited energy state. The excitons cause the fluorescent molecules in the emissive layer to emit light when they return from the excited state to the ground state.

In top-emission organic light emitting display devices, the thicker the device profile, the better the microcavity effect. The microcavity effect refers to a phenomenon in which the wavelength of light emitted from a display device depends on the path the light travels within the device. Additionally, a device with a thick profile minimizes particle-induced image defects.

However, when the overall thickness of the device increases, there will be an increase in drive voltage, which can be a problem. In order to maximize its efficiency, it is necessary to provide a suitable light path that allows light to have a wavelength closest to its original wavelength. The light path can be tuned by varying the thickness of the organic layers of the device. In general, the thicker the organic layer, the longer the wavelength of light. The thickest part of the organic layer is the red (R) emitting layer, and the thinnest part of the organic layer is the blue (B) emitting layer. The thickness range has a preferable periodic thickness and can obtain the maximum light extraction efficiency. One period thickness is too thin to prevent poor emission due to particles. The two-period thickness is too thick to prevent an increase in driving voltage even though the two-period thickness prevents poor emission due to particles.

Contents of the invention

One aspect of the present invention provides an organic light emitting display device, comprising: a first electrode; a second electrode; an emission layer interposed between the first and second electrodes; a first electrode interposed between the first electrode and the emission layer. A hole injection layer; a second hole injection layer inserted between the first hole injection layer and the emission layer; a charge generation layer inserted between the first hole injection layer and the second hole injection layer, the charge generation The layer is doped with a p-type dopant.

The charge generation layer may include a compound represented by Formula 1:

Formula 1

Where R is a nitrile group (-CN), a sulfone group (-SO ₂ R'), a sulfoxide group (-SOR'), a sulfone amide group (-SO ₂ NR' ₂ ), a sulfonic acid group (-SO ₃ R' ), nitro (-NO ₂ ) or trifluoromethyl (-CF ₃ ); and wherein R' is an alkyl group having 1-60 carbon atoms and is unsubstituted or substituted by amine, amide, ether or ester, aryl or heterocyclyl.

The p-type dopant may include hexanitrile hexaazatriphenylene (hexanitrilehexaazatriphenylene), tetrafluoro-tetracyanoquinodimethane (tetrafluoro-tetracyanoquinodimethane, F ₄ -TCNQ), FeCl ₃ , F ₁₆ at least one of CuPc and metal oxides. The metal oxide may include at least one selected from vanadium oxide (V ₂ O ₅ ), rhenium oxide (Re ₂ O ₇ ), and indium tin oxide (ITO). A p-type dopant may have a lowest unoccupied molecular orbital (LUMO) energy level. At least one of the first and second hole injection layers may include a material having a highest occupied molecular orbital (HOMO) energy level. The difference between the lowest unoccupied molecular orbital (LUMO) energy level of the p-type dopant and the highest occupied molecular orbital (HOMO) energy level of the material of at least one of the first and second hole injection layers may be about - Between 2eV and about +2eV.

的厚度。电荷产生层可具有约

-约

的厚度。The device may comprise a large number of pixels, and the charge generation layer may form a common layer for at least two pixels. The charge generation layer can have about -about

thickness of. The charge generation layer can have about

-about

thickness of.

The organic light emitting display device may further include a hole transport layer interposed between the first electrode and the emission layer, and at least one of the hole blocking layer, the electron transport layer, and the electron injection layer interposed between the emission layer and the second electrode. one. The organic light emitting display device may further include an electron transport layer interposed between the second electrode and the emission layer. The organic light emitting display device may further include a substrate on which the first electrode is formed. The organic light emitting display device may further include an electron injection layer interposed between the electron transport layer and the second electrode. The organic light emitting display device may further include a hole blocking layer interposed between the electron transport layer and the emission layer.

Another aspect of the present invention provides an electronic device including the above organic light emitting display device.

Still another aspect of the present invention provides a method of manufacturing an organic light-emitting display device, the method comprising: forming a first hole injection layer on the first electrode; forming a charge generation layer on the first hole injection layer, and the charge generation layer doped with a p-type dopant; and forming a second hole injection layer on the charge generation layer.

The method may further include: forming an emission layer on the second hole injection layer; and forming a second electrode on the emission layer. The method may further include: forming a hole transport layer after forming the second hole injection layer and before forming the emission layer; and forming a hole blocking layer, an electron transport layer, and an electron injection layer after forming the emission layer and before forming the second electrode. At least one of the layers.

The charge generation layer may include a compound represented by Formula 1:

Formula 1

Where R is a nitrile group (-CN), a sulfone group (-SO ₂ R'), a sulfoxide group (-SOR'), a sulfone amide group (-SO ₂ NR' ₂ ), a sulfonic acid group (-SO ₃ R' ), nitro (-NO ₂ ) or trifluoromethyl (-CF ₃ ); and wherein R' is an alkyl group having 1-60 carbon atoms and is unsubstituted or substituted by amine, amide, ether or ester, aryl or heterocyclyl.

The p-type dopant may include hexacyanylhexaazatriphenylene, tetrafluoro-tetracyanoquinodimethane (F ₄ -TCNQ), FeCl ₃ , F ₁₆ CuPc and metal oxides at least one. The metal oxide may be at least one selected from vanadium oxide (V ₂ O ₅ ), rhenium oxide (Re ₂ O ₇ ), and indium tin oxide (ITO). A p-type dopant may have a lowest unoccupied molecular orbital (LUMO) energy level. At least one of the first and second hole injection layers may include a material having a highest occupied molecular orbital (HOMO) energy level. The difference between the lowest unoccupied molecular orbital (LUMO) energy level of the p-type dopant and the highest occupied molecular orbital (HOMO) energy level of the material of at least one of the first and second hole injection layers may be about - Between 2eV and about +2eV.

-约

的厚度。Forming the charge generation layer may include vapor deposition using resistance heating, electron beam vapor deposition, laser beam vapor deposition, or sputtering deposition. The charge generation layer can have about

-about

thickness of.

Another aspect of the present invention provides an organic light emitting display device having a reduced driving voltage and a method of manufacturing the same.

Still another aspect of the present invention provides an organic light emitting display device having an emission layer between a first electrode and a second electrode, the device comprising: a first hole injection layer and a second hole injection layer between the first electrode and the emission layer two hole injection layers; and a charge generation layer doped with a p-type dopant between the first hole injection layer and the second hole injection layer.

Still another aspect of the present invention provides a method of manufacturing an organic light emitting display device having an emission layer between a first electrode and a second electrode, the method comprising: forming a first hole injection layer on the first electrode; A charge generation layer doped with a p-type dopant is formed on the hole injection layer; and a second hole injection layer is formed on the charge generation layer.

Description of drawings

The above and other aspects of the invention will become more apparent by describing in detail exemplary embodiments with reference to the accompanying drawings, in which:

1 is a cross-sectional view of an organic light emitting display device; and

2A to 2C are cross-sectional views illustrating a method of manufacturing an organic light emitting display device according to an embodiment.

Detailed ways

Hereinafter, the present disclosure will be described in detail by illustrating certain inventive embodiments with reference to the accompanying drawings.

An organic electroluminescence (EL) display device having an emission layer between a first electrode and a second electrode according to an embodiment includes a first hole injection layer and a second hole injection layer between the first electrode and the emission layer. Cave injection layer. The organic EL device may include a charge generation layer between the first hole injection layer and the second hole injection layer. The charge generation layer may be doped with a p-type dopant.

The charge generation layer according to this embodiment may include a compound represented by Formula 1:

Formula 1

In Formula 1, R is a nitrile group (-CN), a sulfone group (-SO ₂ R'), a sulfoxide group (-SOR'), a sulfone amide group (-SO ₂ NR' ₂ ), a sulfonic acid group (- SO ₃ R'), nitro (-NO ₂ ) or trifluoromethyl (-CF ₃ ) (wherein R' is unsubstituted or substituted with amine, amide, ether or ester having 1-60 carbon atoms alkyl, aryl or heterocyclyl). Examples of compounds of formula 1 include, but are not limited to, compounds represented by the following formula:

In the above formula, R' is an alkyl, aryl or heterocyclic ring having 1 to 60 carbon atoms and being unsubstituted or substituted with amine, amide, ether or ester. The organic material forming the charge generation layer represented by the above formula is for illustrative purposes only and is not limited thereto.

The p-type dopant in the charge generation layer may be selected from the group consisting of hexacyanylhexaazatriphenylene, tetrafluoro-tetracyanoquinodimethane (F ₄ -TCNQ), FeCl ₃ , F ₁₆ CuPc and One of the metal oxides. The metal oxide may be vanadium oxide (V ₂ O ₅ ), rhenium oxide (Re ₂ O ₇ ), or indium tin oxide (ITO).

The p-type dopant material may be a material having an energy level different from that of the first and/or second hole injection layer material. The difference between the lowest unoccupied molecular orbital (LUMO) energy level of the p-type dopant material and the highest occupied molecular orbital (HOMO) energy level of the first hole injection layer and/or second hole injection layer material can be From about -2eV to about +2eV.

For example, hexaazatriphenylene has a HOMO level of about 9.6 eV to about 9.7 eV, and a LUMO level of about 5.5 eV. In addition, tetrafluoro-tetracyanoquinodimethane (F ₄ -TCNQ) has a HOMO energy level of about 8.53 eV, and a LUMO energy level of about 6.23 eV. The first and second hole injection layer materials used in the organic light emitting display device according to the present embodiment have a HOMO energy level of about 4.5 eV to about 5.5 eV. Therefore, when hexaazatriphenylene is used as the p-type dopant material, the difference between the LUMO energy level of the charge generation layer and the HOMO energy level of the first hole injection layer material or the second hole injection layer material The difference is about -1.0eV to 0eV. In addition, when tetrafluoro-tetracyanoquinodimethane (F ₄ -TCNQ) is used as the p-type dopant material in the charge generation layer, the LUMO energy level of the charge generation layer and the first hole injection layer Or the difference between the HOMO levels of the second hole injection layer is about −0.73 to about 1.73 eV.

By forming a charge generation layer between the first hole injection layer and the second hole injection layer using a charge generation material, the driving voltage of the organic light emitting display device can be reduced.

According to one embodiment, the charge generation layer may be formed using resistance heating vapor deposition, electron beam vapor deposition, laser beam vapor deposition, sputter deposition, or the like. The charge generating layer may be formed of a compound represented by Formula 1, wherein R' in Formula 1 is a C ₅ -C ₆₀ alkyl group which is unsubstituted or substituted with amine, amide, ether or ester. The charge generation layer can be formed by inkjet printing, spin coating, blade coating, roll coating, or the like. In these methods, a solution is used instead of using a vapor deposition method to form the charge generation layer.

-约

的厚度，任选地约

-约当电荷产生层的厚度小于

时，电荷产生作用较低。当产生层的厚度大于时，由于会出现泄漏电流而导致驱动电压增加或串扰。In one embodiment, the charge generation layer may form a common layer for each of the plurality of pixels. The charge generation layer can have about

-about

thickness, optionally approx.

-about When the thickness of the charge generation layer is less than

, the charge generation effect is low. When the resulting layer thickness is greater than , an increase in drive voltage or crosstalk may occur due to leakage current.

The organic light emitting display device according to the current embodiment may further include a hole transport layer between the first electrode and the emission layer. The device may further include at least one of a hole blocking layer, an electron transport layer, and an electron injection layer between the emission layer and the second electrode.

According to another embodiment, there is provided a method of manufacturing an organic light emitting display device having an emission layer between a first electrode and a second electrode, the method comprising: forming a first hole injection layer on the first electrode; A charge generation layer doped with a p-type dopant is formed on the hole injection layer; and a second hole injection layer is formed on the charge generation layer. A method of manufacturing an organic light emitting display device according to the present embodiment will now be described in detail.

2A to 2C illustrate a method of manufacturing an organic light emitting display device according to one embodiment. First, an anode (first electrode) material is deposited on a substrate to form the anode. Here, any substrate suitable for an organic light emitting display device may be used as the substrate. Examples of substrates may include, but are not limited to, glass or transparent plastic substrates with good transparency, surface smoothness, ease of handling, and water resistance. Anode materials may include high work function metals (≥about 4.5eV) or transparent and highly conductive indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO ₂ ), zinc oxide (ZnO), and the like.

A first hole injection (HIL) layer may be formed on the anode. The first hole injection layer may be formed by thermally evaporating the hole injection layer material in a high vacuum. In other embodiments, the material may be used in solution. In these embodiments, the layers may be formed by spin coating, dip coating, blade coating, inkjet printing or thermal transfer, organic vapor phase deposition (OVPD), and the like.

当第一空穴注入层的厚度小于

时，空穴注入特性下降。当第一空穴注入层的厚度大于时，驱动电压增加。在顶部发射型有机发光显示设备的一种实施方案中，第一空穴注入层的厚度可在约1000-约

的范围内。As described above, the first hole injection layer (HIL) may be formed using vacuum thermal deposition, spin coating, or the like. The thickness of the first hole injection layer can be about -about

When the thickness of the first hole injection layer is less than

, the hole injection characteristics deteriorate. When the thickness of the first hole injection layer is greater than , the driving voltage increases. In one embodiment of the top emission organic light emitting display device, the thickness of the first hole injection layer may be in the range of about 1000 to about

In the range.

Examples of materials for the first hole injection layer include but are not limited to copper phthalocyanine (CuPc) or starburst amine series such as TCTA, m-MTDATA, IDE406 (available from Idemitsu Kosan, Tokyo, Japan) and the like. Below are the chemical formulas of CuPc, TCTA and m-MTDATA.

A charge generation layer may be formed on the first hole injection layer. The material forming the charge generation layer may be, but not limited to, a compound represented by the following formula 1:

Formula 1

In Formula 1, R is a nitrile group (-CN), a sulfone group (-SO ₂ R'), a sulfoxide group (-SOR'), a sulfone amide group (-SO ₂ NR' ₂ ), a sulfonic acid group ( -SO ₃ R'), nitro (-NO ₂ ) or trifluoromethyl (-CF ₃ ). R' is an alkyl, aryl or heterocyclic group having 1-60 carbon atoms and being unsubstituted or substituted with amine, amide, ether or ester.

The charge generation layer may be doped with a p-type dopant. The p-type dopant may be selected from hexacyanylhexaazatriphenylene, tetrafluoro-tetracyanoquinodimethane (F ₄ -TCNQ), FeCl ₃ , F ₁₆ CuPc and metal oxides at least one. The metal oxide may be vanadium oxide (V ₂ O ₅ ), rhenium oxide (Re ₂ O ₇ ), or indium tin oxide (ITO).

约

的厚度，任选地约

-约

当电荷产生层的厚度小于

时，电荷产生作用降低。当电荷产生层的厚度大于

时，驱动电压增加。The charge generation layer can be formed by depositing a charge generation layer material on the first hole injection layer using resistance heating vapor deposition, electron beam vapor deposition, laser beam vapor deposition, sputtering, or the like. The charge generation layer may form a common layer for a plurality of pixels. The charge generation layer can have about-

about

thickness, optionally approx.

-about

When the thickness of the charge generation layer is less than

, the effect of charge generation decreases. When the thickness of the charge generation layer is greater than

, the driving voltage increases.

-约

A second hole injection layer (HIL) may be formed by depositing a second hole injection layer material on the charge generation layer. The second HIL may be formed using various methods such as vacuum thermal deposition, spin coating, and the like. The material of the second hole injection layer is not particularly limited, but may be the same as that used for the first hole injection layer. The thickness of the second hole injection layer can be about

-about

时，空穴传递特性下降。当第二空穴注入层的厚度大于

时，驱动电压增加。When the thickness of the second hole injection layer is less than

, the hole transport properties are degraded. When the thickness of the second hole injection layer is greater than

, the driving voltage increases.

A hole transport layer (HTL) may optionally be formed by depositing a hole transport layer material on the second hole injection layer. The HTL can be formed using various methods such as vacuum thermal deposition, spin coating, and the like. Examples of hole transport layer materials include, but are not limited to, N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1-biphenyl]-4,4'- Diamine (TPD), N,N'-bis(naphthalen-1-yl)-N,N'-diphenylbenzidine (α-NPD), IDE 320 (available from Idemitsu Kosan Corporation), and the like. The thickness of the hole transport layer can be about -about

时，空穴传递特性下降。当空穴传递层的厚度大于

时，驱动电压增加。When the thickness of the hole transport layer is less than

, the hole transport properties are degraded. When the thickness of the hole transport layer is greater than

, the driving voltage increases.

An emission layer (EML) may be formed on the hole transport layer. There is no particular limitation on the method of forming the emissive layer, and various methods such as vacuum deposition, inkjet printing, laser-induced thermal imaging, photolithography, organic vapor phase deposition (OVPD), etc. can be used to form the emissive layer. The thickness of the emitting layer can be about 100 to about

时，其效率和寿命降低。当发射层的厚度大于时，驱动电压增加。可通过使用如上所述的真空沉积或旋涂在发射层上沉积形成空穴阻挡层(HBL)的材料来任选地形成HBL。对形成HBL的材料没有特殊限制，但可为具有电子传递能力和电离势比发射化合物高的材料。形成HBL的材料的例子包括Balq、BCP、TPBI等。空穴阻挡层的厚度可为约-约

When the thickness of the emitting layer is less than

, its efficiency and life are reduced. When the thickness of the emitting layer is greater than , the driving voltage increases. The HBL may optionally be formed by depositing a hole blocking layer (HBL) forming material on the emissive layer using vacuum deposition or spin coating as described above. The material forming the HBL is not particularly limited, but may be a material having electron transport capability and higher ionization potential than the emissive compound. Examples of materials forming the HBL include Balq, BCP, TPBI, and the like. The thickness of the hole blocking layer can be about -about

时，空穴阻挡特性差，导致效率降低。当空穴阻挡层的厚度大于时，驱动电压增加。When the thickness of the hole blocking layer is less than

When , the hole-blocking properties are poor, resulting in a decrease in efficiency. When the thickness of the hole blocking layer is greater than , the driving voltage increases.

An electron transport layer (ETL) may be formed on the hole blocking layer using vacuum deposition or spin coating. The material of the electron transport layer is not particularly limited, and may be Alq3. The thickness of the electron transport layer can be about -about

时，设备寿命减少。当电子传递层的厚度大于

时，驱动电压增加。When the thickness of the electron transport layer is less than

, the life of the equipment is reduced. When the thickness of the electron transport layer is greater than

, the driving voltage increases.

-约

In addition, an electron injection layer (EIL) may optionally be formed on the electron transport layer. The material forming the electron injection layer may be LiF, NaCl, CsF, Li ₂ O, BaO, Liq and the like. The thickness of the electron injection layer can be about

-about

时，不能有效地用作电子注入层。当电子注入层的厚度大于

时，其用作绝缘层，从而具有高的驱动电压。When the thickness of the electron injection layer is less than

, it cannot be effectively used as an electron injection layer. When the thickness of the electron injection layer is greater than

, it acts as an insulating layer, thereby having a high driving voltage.

Subsequently, a cathode (or a second electrode) may be formed by depositing a metal for forming the cathode on the electron injection layer. The cathode can be formed using vacuum thermal deposition, sputtering, metal-organic chemical vapor deposition, and the like. Examples of metals used to form the cathode include, but are not limited to, lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), and Magnesium-silver (Mg-Ag).

As described above, the organic light emitting display device according to the present embodiment includes an anode, a first hole injection layer, a charge generation layer, a second hole injection layer, a hole transport layer, an emission layer, an electron transport layer, an electron injection layer, and cathode. The device may also comprise an intermediate layer between the two above-mentioned layers. The device may also include an electron blocking layer between the emissive layer and the hole transport layer.

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

Example 1

15Ω/cm ² ( ) Corning ITO glass substrates (available from Corning, Inc., Corning, NY) were cut to 50 mm × 50 mm × 0.7 mm, and were ultrasonically cleaned in isopropanol and pure water for 5 minutes each, and then cleaned with UV and ozone 30 minutes.

厚的第一空穴注入层。使用电阻热气相沉积在第一空穴注入层上沉积作为形成电荷产生层的材料的六氮杂三苯撑至的厚度。在电荷产生层上真空沉积铜m-MTDATA形成厚的第二空穴注入层。在第二空穴注入层上真空沉积N，N’-二(1-萘基)-N，N’-二苯基联苯胺(α-NPD)形成

厚的空穴传递层。Vacuum deposition of m-MTDATA on the substrate to form

thick first hole injection layer. Hexaazatriphenylene as a material for forming the charge generation layer was deposited on the first hole injection layer using resistive thermal vapor deposition to thickness of. Formation of vacuum-deposited copper m-MTDATA on the charge generation layer thick second hole injection layer. Vacuum-deposit N, N'-di(1-naphthyl)-N, N'-diphenylbenzidine (α-NPD) on the second hole injection layer to form

thick hole transport layer.

厚的电子传递层。在电子传递层上依次真空沉积

的LiF(电子注入层)和

的Mg-Ag合金(阴极)形成LiF/Al电极，这样就完成了有机发光显示设备。Using organic vapor phase deposition (OVPD) to form a thickness of about the emission layer. Deposit the electron transport material Alq3 on the emissive layer to form

Thick electron transport layer. Sequential vacuum deposition on the electron transport layer

LiF (electron injection layer) and

The Mg-Ag alloy (cathode) of the LiF/Al electrode is formed, thus completing the organic light-emitting display device.

Example 2

An organic light-emitting display device was manufactured in the same manner as in Example 1, except that the thickness of the charge generation layer was

Example 3

An organic light-emitting display device was manufactured in the same manner as in Example 1, except that the thickness of the charge generation layer was

Comparative Example 1

15Ω/cm ² ( ) Corning ITO glass substrate cut to 50 mm × 50 mm × 0.7 mm, and ultrasonic cleaning in isopropanol and pure water respectively for 5 minutes, and then cleaning with UV and ozone for 30 minutes.

厚的空穴注入层。在空穴注入层上真空沉积N，N’-二(1-萘基)-N，N’-二苯基联苯胺(α-NPD)形成

厚的空穴传递层。Vacuum deposition of m-MTDATA on the substrate to form

thick hole injection layer. Vacuum deposition of N,N'-bis(1-naphthyl)-N,N'-diphenylbenzidine (α-NPD) on the hole injection layer to form

thick hole transport layer.

的发射层。在发射层上沉积电子传递材料Alq3形成厚的电子传递层。在电子传递层上依次真空沉积

的LiF(电子注入层)和

的Mg-Ag合金(阴极)形成LiF/Al电极，这样就制造了如图1所示的有机发光显示设备。Using organic vapor phase deposition (OVPD) to form a thickness of about

the emission layer. Deposit the electron transport material Alq3 on the emissive layer to form Thick electron transport layer. Sequential vacuum deposition on the electron transport layer

LiF (electron injection layer) and

The Mg-Ag alloy (cathode) of the LiF/Al electrode is formed, and thus the organic light-emitting display device as shown in FIG. 1 is manufactured.

The driving voltage, efficiency, and lifetime of the organic light emitting display devices manufactured according to Examples 1 to 3 and Comparative Example 1 were measured, and the results are shown in Table 1 below.

Table 1

Driving voltage (V) Efficiency (cd/A) lifespan (hours) Example 1 5.73 27.18 1,500 Example 2 5.71 26.90 1,500 Example 3 5.60 26.85 1,500 Comparative Example 1 7.59 26.79 1,000

In Examples 1 to 3, the driving voltage was 5.73-5.60V, and in Comparative Example 1, the driving voltage was 7.59V. In addition, in Examples 1 to 3, the efficiency at a brightness of 1900cd/ ^m2 was 27.18-26.90cd/A, and in Comparative Example 1, the efficiency at a brightness of 1900cd/ ^m2 was 26.85cd/A .

In addition, the lifetime is defined as the time required for the luminance to decrease to 50% of the initial luminance. In Examples 1 to 3, the lifetime at 9,500 cd/m ² was about 1,500 hours, and in Comparative Example 1, the lifetime at 9,500 cd/m ² was about 1,000 hours. Therefore, it can be seen that the lifetime of Examples 1-3 is about 1.5 times that of Comparative Example 1.

An organic light emitting display device according to the present disclosure includes a charge generation layer, thereby reducing a driving voltage of the organic light emitting display device and improving efficiency and lifetime thereof.

While the present disclosure has been particularly illustrated and described with reference to exemplary embodiments, those of ordinary skill in the art will recognize that changes may be made in form and without departing from the spirit and scope of the invention as defined in the following claims. Various changes in details.

Claims (23)

1. An organic light-emitting display device, comprising: first electrode; second electrode; an emissive layer interposed between the first and second electrodes; a first hole injection layer interposed between the first electrode and the emissive layer; a charge generation layer formed on the first hole injection layer, the charge generation layer doped with a p-type dopant; and A second hole injection layer is formed on the charge generation layer. 2. The organic light emitting display device of claim 1, wherein the charge generation layer comprises a compound represented by Formula 1: Formula 1 Where R is a nitrile group (-CN), a sulfone group (-SO ₂ R'), a sulfoxide group (-SOR'), a sulfone amide group (-SO ₂ NR' ₂ ), a sulfonic acid group (-SO ₃ R' ), nitro (-NO ₂ ) or trifluoromethyl (-CF ₃ ); and wherein R' is an alkyl, aryl or heterocyclic group having 1-60 carbon atoms and being unsubstituted or substituted by amine, amide, ether or ester. 3. The organic light emitting display device of claim 1, wherein the p-type dopant comprises hexacyanylhexaazatriphenylene, tetrafluoro-tetracyanoquinodimethane (F ₄ -TCNQ), FeCl _3. At least one of F ₁₆ CuPc and metal oxides. 4. The organic light emitting display device of claim 3, wherein the metal oxide includes at least one selected from vanadium oxide (V ₂ O ₅ ), rhenium oxide (Re ₂ O ₇ ), and indium tin oxide (ITO). 5. The organic light-emitting display device of claim 1 , wherein the p-type dopant has the lowest unoccupied molecular orbital (LUMO) energy level, wherein at least one of the first and second hole injection layers comprises the highest occupied molecular orbital (HOMO) level material, and wherein the lowest unoccupied molecular orbital (LUMO) energy level of the p-type dopant is the highest occupied molecular orbital (HOMO) level of the material of at least one of the first and second hole injection layers The difference between the energy levels is between -2eV and +2eV. 6. The organic light emitting display device of claim 1, wherein the device comprises a large number of pixels, and wherein the charge generation layer forms a common layer for at least two pixels. 7. The organic light emitting display device of claim 1, wherein the charge generation layer has

thickness of. 8. The organic light emitting display device of claim 1, wherein the charge generation layer has thickness of. 9. The organic light-emitting display device of claim 1, further comprising a hole transport layer interposed between the first electrode and the emission layer, and a hole blocking layer, an electron transport layer, and an electron transport layer interposed between the emission layer and the second electrode. At least one of the electron injection layers. 10. The organic light emitting display device of claim 1, further comprising an electron transfer layer interposed between the second electrode and the emission layer. 11. The organic light emitting display device of claim 10, further comprising a substrate, wherein the first electrode is formed on the substrate. 12. The organic light emitting display device of claim 11, further comprising an electron injection layer interposed between the electron transport layer and the second electrode. 13. The organic light emitting display device of claim 12, further comprising a hole blocking layer interposed between the electron transport layer and the emission layer. 14. An electronic device comprising the organic light emitting display device of claim 1. 15. A method of manufacturing an organic light emitting display device, the method comprising: forming a first hole injection layer on the first electrode; forming a charge generation layer doped with a p-type dopant on the first hole injection layer; and A second hole injection layer is formed on the charge generation layer. 16. The method of claim 15, further comprising: forming an emissive layer on the second hole injection layer; and A second electrode is formed on the emission layer. 17. The method of claim 16, further comprising: forming the hole transport layer after forming the second hole injection layer and before forming the emissive layer; and At least one of the hole blocking layer, the electron transport layer and the electron injection layer is formed after the emission layer is formed and before the second electrode is formed. 18. The method of claim 15, wherein the charge generation layer comprises a compound represented by Formula 1: Formula 1

Where R is a nitrile group (-CN), a sulfone group (-SO ₂ R'), a sulfoxide group (-SOR'), a sulfone amide group (-SO ₂ NR' ₂ ), a sulfonic acid group (-SO ₃ R' ), nitro (-NO ₂ ) or trifluoromethyl (-CF ₃ ); and wherein R' is an alkyl, aryl or heterocyclic group having 1-60 carbon atoms and being unsubstituted or substituted by amine, amide, ether or ester. 19. The method of claim 15, wherein the p-type dopant comprises hexacyanylhexaazatriphenylene, tetrafluoro-tetracyanoquinodimethane (F ₄ -TCNQ), FeCl ₃ , F ₁₆ At least one of CuPc and metal oxides. 20. The method of claim 19, wherein the metal oxide is at least one selected from the group consisting of vanadium oxide (V ₂ O ₅ ), rhenium oxide (Re ₂ O ₇ ), and indium tin oxide (ITO). 21. The method of claim 15, wherein the p-type dopant has the lowest unoccupied molecular orbital (LUMO) energy level, wherein at least one of the first and second hole injection layers comprises Energy level material, and wherein the lowest unoccupied molecular orbital (LUMO) energy level of the p-type dopant is between the highest occupied molecular orbital (HOMO) energy level of the material of at least one of the first and second hole injection layers The difference between -2 and +2eV. 22. The method of claim 15, wherein forming the charge generation layer comprises vapor deposition using resistance heating, electron beam vapor deposition, laser beam vapor deposition, or sputter deposition. 23. The method of claim 15, wherein the charge generation layer has thickness of.

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