KR101617877B1 - Organic light emitting diode - Google Patents

Abstract

The present invention provides an organic light emitting diode including a host / dopant type light emitting layer containing a dopant having an improved horizontal orientation. One embodiment of an organic light emitting diode according to an aspect of the present invention includes: an anode layer; A light emitting layer comprising a dopant including a host including a hole transporting material and an electron transporting material forming an exciplex and an Ir (mphmq) ₂ tmd based phosphorescent material located on the anode layer; And a cathode layer disposed on the light emitting layer.

Description

[0001] The present invention relates to an organic light emitting diode

The present invention relates to an organic light emitting diode (OLED), and more particularly, to an organic light emitting diode employing a light emitting layer (EML) including a host and a phosphorescent dopant.

Typical examples of the organic light emitting diode include a cathode layer, an electron transporting layer, a light emitting layer, a hole transporting layer, and a cathode layer. In organic light emitting diodes, an electron transporting layer, a light emitting layer and a hole transporting layer are usually based on organic compounds. When a voltage is applied between the cathode layer and the anode layer, holes are injected from the anode layer to the light emitting layer through the hole transporting layer. The electrons are injected from the cathode layer to the light emitting layer through the electron transporting layer. The holes and electrons supplied to the light emitting layer recombine in the light emitting layer to form an exciton. The excitons dissipate and release energy. The energy emitted from the excitons excites the luminescent material in the luminescent layer. The excited luminescent material changes to a ground state and generates light.

The light emitting material of the light emitting layer of the organic light emitting diode may be a phosphor excited by singlet excitons or a phosphor excited by triplet excitons. The statistical production ratio of singlet excitons to triplet excitons in the luminescent layer is known to be 1: 3. When the luminescent material present in the luminescent layer is a fluorescent material, the triplet exciton does not contribute to the generation of light and is wasted. When the luminescent material present in the luminescent layer is a phosphorescent material, both singlet excitons and triplet excitons can contribute to the generation of light, so that the internal quantum efficiency of the luminescent layer can reach 100%.

The light emitting layer may include an undoped host. Alternatively, the light emitting layer may include a host and a dopant. The host serves as a matrix that forms the physical form of the light emitting layer. The dopant is dispersed in the matrix. When the light emitting layer includes a host that is not doped, the host itself may be a light emitting material. When the light emitting layer includes a host and a dopant, the dopant is a luminescent material, and the host may or may not be a luminescent material.

When the light emitting layer includes a host that is not doped, the host may form an excimer, thereby reducing color purity and degrading efficiency. The light emitting layer including the host and the dopant has an improved color purity and can also attain an increase in efficiency through energy transfer as compared with the light emitting layer including the undoped host.

The luminous efficiency of the organic light emitting diode has been increased by employing a phosphorescent material and a light emitting layer employing a host / dopant method. For example, some of the actually fabricated organic light emitting diodes have reached an external quantum efficiency of 29%. In particular, the external quantum efficiency of the red organic light emitting diode reached 26%. However, the emission efficiency of organic light emitting diodes is still unsatisfactory.

The external quantum efficiency of the organic light emitting diode is determined by "external light efficiency x internal quantum efficiency x charge balance ". Therefore, by increasing the external light efficiency of the light emitting layer, the external quantum efficiency of the organic light emitting diode can be improved.

In a light emitting layer employing a host / dopant system, theoretical calculations show that the external light efficiency of the light emitting layer can not exceed 30% unless the dopant is oriented in the host matrix. On the other hand, it is known that, if the dopant can be oriented horizontally in the host matrix, the external light efficiency of the light emitting layer can be increased to some extent. However, there is no example in which a host / dopant type light emitting layer including a horizontally oriented dopant is implemented. Furthermore, there are no cases in which an organic light emitting diode device having an external quantum efficiency of 30% or more is implemented.

The present invention provides an organic light emitting diode including a host / dopant type light emitting layer containing a dopant having an improved horizontal orientation.

An embodiment of an organic light emitting diode according to an aspect of the present invention includes:

An anode layer;

A light emitting layer comprising a dopant including a host including a hole transporting material and an electron transporting material forming an exciplex and an Ir (mphmq) ₂ tmd based phosphorescent material located on the anode layer; And

And a cathode layer disposed on the light emitting layer.

According to the present invention, when a hole transporting material and an electron transporting material which form an exciplex as a host are used in combination in a light emitting layer and an Ir (mphmq) 2tmd based phosphorescent material is used as a dopant, The horizontal orientation ratio of the dopant increases sharply.

Although not limited to a particular mechanism, it is believed that this is due to the interaction between the host comprising the hole transport material and the electron transport material forming the exciplex and the Ir (mphmq) 2tmd phosphorescent material. For example, the refractive index of the host including the NPB-based hole transporting material and the B3PYMPM-based electron transporting material forming the exciplex shows optically anisotropy, and the Ir (mphmq) 2tmd-based phosphorescent material exhibits a chemical structural asymmetry . The fact that the refractive index of the host material has optical anisotropy means that the host material has an orientation in a specific direction. Therefore, it is presumed that the orientation of the host material induces the horizontal orientation of the dopant material. It is also assumed that the horizontal orientation of the Ir (mphmq) 2tmd phosphorescent dopant is promoted by the asymmetry in the chemical structure of the Ir (mphmq) 2tmd phosphorescent dopant.

Since the horizontal orientation ratio of the dopant in the light emitting layer of the present invention is very high, the light emitting layer of the present invention can exhibit greatly improved external light efficiency. Accordingly, the organic light emitting diode including the light emitting layer of the present invention can have a greatly improved external quantum efficiency.

1 is an emission spectrum of the organic light emitting diode of Example 1. Fig.
Fig. 2 shows the result of measurement of the horizontal orientation ratio of the Ir (mphmq) ₂ tmd phosphor in the light emitting layer of the organic light emitting diode of Example 1. Fig.
3 is a graph showing a result of measuring the horizontal orientation ratio of the Ir (ppy) ₂ acac phosphor in the light emitting layer of the organic light emitting diode of Comparative Example 1. FIG.
4 is a graph showing the relationship between the voltage-current density and the light emission luminance for the organic light emitting diode of Example 1. Fig.
5 is a graph showing the relationship between the luminance and the external quantum efficiency for the organic light emitting diode of Example 1. Fig.
6 is a graph showing the relationship between the luminance and the power efficiency for the organic light emitting diode of Example 1. Fig.
7 is a graph showing the relation between the voltage-current density and the light emission luminance for the organic light emitting diode of Comparative Example 1. Fig.
8 is external quantum efficiency and power efficiency for the organic light emitting diode of Comparative Example 1. Fig.

Hereinafter, the organic light emitting diode according to one aspect of the present invention will be described in more detail. An embodiment of an organic light emitting diode according to an aspect of the present invention includes:

An anode layer;

A light emitting layer comprising a dopant including a host including a hole transporting material and an electron transporting material forming an exciplex and an Ir (mphmq) ₂ tmd based phosphorescent material located on the anode layer; And

And a cathode layer disposed on the light emitting layer.

Exciplex refers to excited state charge transfer complexes. In the present invention, the host of the light emitting layer comprises a hole transporting material and an electron transporting material, and the hole transporting material and the electron transporting material form a pair of materials forming an exciplex. The hole transport material forming the exciplex: electron transport material pair includes, but is not limited to, NPB: B3PYMPM, TCTA: B3PYMPM, TCTA: TPBi, TCTA: 3TPYMB, TCTA: BmPyPB, TCTA: BSFM, CBP: B3PYMPM, Or NPB: BSFM.

<Hole transport material>

<Electron transport material>

Ir (mphmq) ₂ tmd phosphorescent material is Ir (mphmq) ₂ tmd wherein mphmq = 2- (3,5-dimethylphenyl) -4-methylquinoline, tmd = 2,2,6,6-tetramethylheptane-3,5 -dionate) and derivatives thereof.

&Lt; Ir (mphmq) ₂ tmd >

When the content of the electron transporting material is too small relative to the content of the hole transporting material in the light emitting layer, the electron transporting property is dominant, while the hole transporting is relatively high.

In the light emitting layer, if the content of the Ir (mphmq) ₂ tmd-based phosphor is too small, the efficiency may decrease. In the light emitting layer, if the content of the Ir (mphmq) ₂ tmd-based phosphor is too large, the dopant excitons may self-destruct themselves and the efficiency may decrease.

For example, in the light emitting layer, the content of the electron transporting material may be about 50 to about 150 moles, based on 100 moles of the hole transporting material.

For example, in a light emitting layer, by the Ir (mphmq) ₂ content of tmd-based phosphors, based on the total weight of 100 wt% of the hole transport material, electron transport material and Ir (mphmq) ₂ tmd-based phosphor, about 1 wt% to about 20 wt%.

The horizontal alignment transition dipole ratio of the dopant in the light emitting layer means the ratio of the dopant molecules positioned in parallel with the main surface of the light emitting layer and the transition dipole direction among all the dopant molecules in the light emitting layer.

The higher the horizontal orientation ratio of the transition dipole moments of the dopant in the light emitting layer, the more the external light efficiency of the light emitting layer is increased. The dopant having a vertically aligned transition dipole moment emits an electric field mainly in a direction perpendicular to the plane of the light emitting layer. The emitted light propagates in a waveguide mode propagating into the light emitting layer and the transparent electrode layer, a surface plasmon polaritons (SPP) ). On the contrary, the dopant having the horizontal alignment transition dipole moment emits an electric field in a horizontal direction on the main surface of the light emitting layer, and the light emitted in such a manner has a large rate of progressing to the outside of the device. Therefore, the higher the horizontal alignment transition dipole ratio than the vertical alignment transition dipole, the more the external light efficiency increases and the external quantum efficiency increases.

In the present invention, the horizontal orientation ratio of the Ir (mphmq) ₂ tmd dopant in the light emitting layer is very high. In the host, when the dopant is randomly oriented, the horizontal orientation rate of the dopant is about 67%. According to the theoretical calculation, when the horizontal orientation ratio of the dopant is about 67%, the external light efficiency of the light emitting layer is only about 25.7%. On the other hand, in the light emitting layer of the present invention, the horizontal orientation ratio of the Ir (mphmq) ₂ tmd dopant may be, for example, about 83% to about 89%. According to the theoretical calculation, when the horizontal orientation ratio of the dopant is about 89%, the external light efficiency of the light emitting layer can be about 35.8%.

In the organic light emitting diode of the present invention, each of the anode layer and the cathode layer may be an opaque electrode, a transparent electrode, or a reflective electrode. In operation of the organic light emitting diode of the present invention, a positive voltage is applied to the anode layer and a negative voltage is applied to the cathode layer. Examples of the opaque electrode include alkali metals such as lithium, sodium, potassium, rubidium and cesium; alkaline earth metals such as beryllium, magnesium, calcium, strontium and barium; Metals such as aluminum, scandium, vanadium, zinc, yttrium, indium, cerium, samarium, europium, terbium and ytterbium; Two or more of these alloys; Or an alloy of one or more of these metals with at least one of gold, silver, platinum, copper, manganese, titanium, cobalt, nickel, tungsten and tin; And a structure including at least two of them. The transparent electrode may be, for example, ITO, IZO, ZnO or graphene. The reflective electrode may be formed by forming a reflective film of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr or a compound thereof, As shown in FIG.

In another embodiment of the organic light emitting diode of the present invention, at least one of a hole transport layer and a hole injection layer may be further interposed between the anode layer and the light emitting layer. The hole transporting layer may preferably include a hole transporting material used in the light emitting layer. The hole-injecting layer may be formed of, for example, a phthalocyanine compound such as copper phthalocyanine, m-MTDATA (4,4 ', 4 "-tris (3-methylphenylphenylamino) triphenylamine), TDATA (4,4' , N-diphenylamino) triphenylamine), TAPC (1,1-bis- (4-bis (4-methylphenylamino-phenyl) -cyclohexane), 2-TNATA (4,4,4- PEDOT / PSS (poly (3,4-ethylenedioxythiophene) / poly (4-styrene) / poly Sulfonate), Pani / CSA (polyaniline / camphorsulfonic acid), Pani / PSS (polyaniline / poly (4-styrenesulfonate)), or mixtures thereof. When both the hole transporting layer and the hole injecting layer are used, a hole injecting layer may be positioned between the anode layer and the hole transporting layer.

In another embodiment of the organic light emitting diode of the present invention, at least one of an electron transport layer and an electron injection layer may be further included between the cathode layer and the light emitting layer. The electron transporting layer may preferably include an electron transporting material used in the light emitting layer. The electron injection layer may include, for example, LiF, NaCl, CsF, Li ₂ O, BaO, or a mixture thereof. When both the electron transporting layer and the electron injecting layer are used, the electron injecting layer may be positioned between the cathode layer and the electron transporting layer.

In another embodiment of the organic light emitting diode of the present invention, the electron transporting layer may further include n dopant. The n-dopant may be, for example, Rb ₂ CO ₃ , Cs ₂ CO ₃ , LiF, or a mixture thereof. By further including an n-dopant in the electron transporting layer, the charge balance between the electron transporting layer and the hole transporting layer can be induced. The charge balance between the electron transporting layer and the hole transporting layer can further improve the external quantum efficiency of the organic light emitting diode.

Hereinafter, an example of a method of manufacturing the organic light emitting diode of the present invention will be described in detail (an embodiment in which the anode layer is located at the bottom) will be described.

First, a positive electrode layer is formed on a substrate. As the substrate, a substrate used for a common organic light emitting device can be used, and a glass substrate or a transparent plastic substrate excellent in mechanical strength, thermal stability, transparency, surface smoothness, ease of handling and waterproofness can be used. For example, the substrate can be formed of a transparent glass material containing SiO ₂ as a main component. The anode layer may be formed by various known methods, for example, a vapor deposition method, a sputtering method, a spin coating method, or the like. A hole injection layer is formed on the anode layer. The hole injection layer may be formed on the anode layer by various methods such as a vacuum deposition method, a spin coating method, a casting method, or a Langmuir-Blodgett (LB) method. A hole transport layer is formed on the hole injection layer. The hole transport layer can be formed by various methods such as a vacuum deposition method, a spin coating method, a casting method, or an LB method. A light emitting layer is formed on the hole transporting layer. The light emitting layer may be formed using various methods such as a vacuum evaporation method, a spin coating method, a casting method, or an LB method. An electron transporting layer is formed on the light emitting layer. Various methods such as a vacuum vapor deposition method, a spin coating method, a casting method, and an LB method can be used for forming the electron transporting layer. And an electron injection layer is formed on the electron transport layer. The electron injection layer may be formed by various methods such as a vacuum evaporation method, a spin coating method, a casting method, or an LB method. A cathode layer is formed on the electron injection layer. The cathode layer may be formed by various known methods, for example, a vapor deposition method, a sputtering method, a spin coating method, or the like.

According to another aspect of the present invention, there is provided an illumination comprising an organic light emitting diode of the present invention. The illumination includes an anode layer; A light emitting layer comprising a dopant including a host including a hole transporting material and an electron transporting material forming an exciplex and an Ir (mphmq) ₂ tmd based phosphorescent material located on the anode layer; And a cathode layer disposed on the light emitting layer.

According to still another aspect of the present invention, there is provided a display device including the organic light emitting diode of the present invention. The display device includes a transistor including a source, a drain, a gate, and an active layer; And an anode layer, a light-emitting layer disposed on the anode layer, the light-emitting layer including a host including a hole transporting material and an electron transporting material forming an exciplex and a dopant including an Ir (mphmq) ₂ tmd based phosphorescent material, A cathode layer or an anode layer of the organic light emitting diode may be electrically connected to one of the source and the drain.

<Examples>

Example  1 --- Fabrication of Organic Light Emitting Diodes The light-  : NPB , B3PYMPM and Ir ( mphmq ) ₂ tmd )

TAPC was deposited on the glass substrate on which ITO 100 nm was deposited by vacuum thermal evaporation at a deposition rate of 1 Å / s under a vacuum of 5 × 10 ^-7 torr or less to form a 75 nm thick hole injection layer.

NPB was deposited on the hole injection layer at a deposition rate of 1 Å / s at a vacuum degree of 5 × 10 ^-7 torr or less by vacuum thermal evaporation to form a hole transport layer having a thickness of 10 nm.

A hole transport layer, a vacuum thermal evaporation in vacuum level of less than 5 x 10 ^-7 torr NPB, B3PYMPM and Ir (mphmq) simultaneously depositing at a deposition rate of ₂ tmd each 0.49 Å / s, 0.46 Å / s, 0.05 Å / s To form a light emitting layer having a thickness of 30 nm. The molar ratio of NPB: B3PYMPM was 1: 1, and the content of tmd of Ir (mphmq) ₂ was 5 wt% based on the total weight of 100 wt% of NPB, B3PYMPM and Ir (mphmq) ₂ tmd.

B3PYMPM was deposited on the light emitting layer at a deposition rate of 1 Å / s at a vacuum of 5 × 10 ^-7 torr or less to form an electron transport layer having a thickness of 10 nm.

B3PYMPM and RB ₂ CO ₃ as n dopants were co-deposited on the electron transport layer at a deposition rate of 0.98 Å / s and 0.02 Å / s, respectively, at a vacuum degree of 5 × 10 ^-7 torr or less, nm thick electron transporting layer for charge balancing was formed. In the electron transport layer for charge balance, RB ₂ CO ₃ is the dose, based on the total weight B3PYMPM and 100 wt% of the RB ₂ CO _3, was 2 wt%.

Al was deposited on the electron transport layer for charge balancing at a deposition rate of 4 A / s at a degree of vacuum of 5 x 10 &lt; ^-7 &gt; torr or less by vacuum thermal evaporation to form an upper electrode of 100 nm thick, .

For the organic light emitting diode of Example 1, a luminescence spectrum was obtained using a spectrophotometer (Spectrascan PR 650, Photoresearch). 1 is an emission spectrum of the organic light emitting diode of Example 1. Fig. As shown in FIG. 1, the organic light emitting diode of Example 1 showed a peak at 612 nm and can be suitably used as a red light element.

Comparative Example  1 --- Fabrication of Organic Light Emitting Diodes The light-  : TCTA , B3PYMPM and Ir ( ppy ) ₂ acac )

TAPC was deposited on the glass substrate on which ITO 100 nm was deposited by vacuum thermal evaporation at a deposition rate of 1 Å / s at a degree of vacuum of 5 × 10 ^-7 torr or less to form a 60 nm thick hole injection layer.

TCTA was deposited on the hole injection layer at a deposition rate of 1 Å / s at a vacuum degree of 5 × 10 ^-7 torr or less by vacuum thermal evaporation to form a hole transport layer having a thickness of 10 nm.

A hole transport layer, a vacuum heat in vacuum of less than 5 x 10 ^-7 torr Deposition, TCTA, B3PYMPM and Ir (ppy) 2acac simultaneously depositing at a deposition rate of 0.52 Å / s, 0.4 Å / s, 0.08 Å / s , respectively To form a light emitting layer having a thickness of 30 nm. The molar ratio of TCTA: B3PYMPM was 1: 1, and the content of Ir (ppy) 2acac was 8 wt% based on the total weight of 100 wt% of TCTA, B3PYMPM and Ir (ppy) 2acac.

TCTA: 4,4 ', 4' '- tris (N-carbazolyl) -triphenylamine

Ir (ppy) 2acac: bis (2-phenylpyridine) iridium (III) acetylacetonate

B3PYMPM was deposited on the light emitting layer by a vacuum thermal evaporation method at a deposition rate of 1 Å / s at a vacuum degree of 5 × 10 ^-7 torr or less to form an electron transport layer having a thickness of 40 nm.

LiF was deposited on the electron transport layer at a deposition rate of 0.01 Å / s at a degree of vacuum of 5 × 10 ^-7 torr or less by vacuum thermal evaporation to form an electron injection layer with a thickness of 0.7 nm.

Al was deposited on the electron injecting layer at a deposition rate of 4 Å / s at a degree of vacuum of 5 × 10 ^-7 torr or less by vacuum thermal evaporation to form an upper electrode having a thickness of 100 nm to manufacture the organic light emitting diode of Comparative Example 1 Respectively.

Reference Example  One --- The light-  formation

NPB, B3PYMPM and Ir (mphmq) 2tmd were deposited on the glass substrate at a deposition rate of 0.49 Å / s, 0.46 Å / s and 0.05 Å / s, respectively, at a vacuum degree of 5 × 10 ^-7 torr or less by vacuum thermal evaporation, B3PYMPM and Ir (mphmq) 2tmd were simultaneously deposited to form a light emitting layer with a thickness of 30 nm. The molar ratio of NPB: B3PYMPM was 1: 1, and the content of Ir (mphmq) 2tmd was 5 wt% based on the total weight of 100 wt% of NPB, B3PYMPM and Ir (mphmq) 2tmd. The light emitting layer of Reference Example 1 is the same as the light emitting layer used for the organic light emitting diode of Example 1.

compare Reference Example  One --- The light-  formation

On a glass substrate, in a vacuum of less than 5 x 10 ^-7 torr in a vacuum thermal deposition method, a deposition rate of TCTA, B3PYMPM and Ir (ppy) 0.52 Å / s for each 2acac, 0.4 Å / s, 0.08 Å / s, TCTA , B3PYMPM and Ir (ppy) 2acac were co-deposited to form a light emitting layer having a thickness of 30 nm. The molar ratio of TCTA: B3PYMPM was 1: 1, and the content of Ir (ppy) 2acac was 8 wt% based on the total weight of 100 wt% of TCTA, B3PYMPM and Ir (ppy) 2acac. The light emitting layer of Comparative Example 1 is the same as the light emitting layer used in the organic light emitting diode of Comparative Example 1.

In the light emitting layer  Phosphorous level Orientation ratio  Measure

A sample deposited on a synthetic quartz substrate is fixed to a semi-cylindrical lens made of synthetic quartz and irradiated with a 325 nm laser to emit light. The emitted light passes through a polarizing film and is measured by a PMT (Photomultiplier tube) and a monochromator (monochromator), and is rotated from -90 to 90 degrees by 1 degree. The p-polarized light emission intensity for each angle and the p-polarized light emission intensity for each angle when the light emitter has a vertical orientation are calculated, and the two values are multiplied by weights respectively, The orientation ratio can be determined.

Fig. 2 shows the result of measuring the horizontal orientation ratio of Ir (mphmq) ₂ tmd phosphorescent material in the light emitting layer of Reference Example 1. Fig. 3 shows the result of measuring the horizontal orientation ratio of Ir (ppy) ₂ acac phosphor in the light emitting layer of Comparative Reference Example 1. As shown in Fig. 2, the horizontal orientation ratio of the Ir (mphmq) ₂ tmd phosphor in the light emitting layer of Reference Example 1 was 89%. On the other hand, as shown in Fig. 3, the horizontal orientation ratio of the Ir (ppy) ₂ acac phosphor in the light emitting layer of Comparative Reference Example 1 was merely 76%. From this, it can be seen that the combination of NPB, B3PYMPM and Ir (mphmq) ₂ tmd exerts an unexpected effect of inducing a horizontal orientation ratio of a very good dopant.

Measurement of external quantum efficiency

The relationship between the voltage-current density and the luminance of the organic light emitting diode of Example 1 and Comparative Example 1 was measured using a photo research spectrophotometer (PR-650) and a power supply (Keithley 2400).

4 is a graph showing the relationship between the voltage-current density and the light emission luminance for the organic light emitting diode of Example 1. Fig. Based on the voltage-current density-emission luminance data of FIG. 4, the external quantum efficiency and power efficiency of the organic light emitting diode of Example 1 were calculated. 5 is a graph showing the relationship between the luminance and the external quantum efficiency for the organic light emitting diode of Example 1. Fig. 6 is a graph showing the relationship between the luminance and the power efficiency for the organic light emitting diode of Example 1. Fig.

7 is a graph showing the relation between the voltage-current density and the light emission luminance for the organic light emitting diode of Comparative Example 1. Fig. The external quantum efficiency and power efficiency of the organic light emitting diode of Comparative Example 1 were calculated based on the voltage-current density-light emission luminance data of FIG. 8 is external quantum efficiency and power efficiency for the organic light emitting diode of Comparative Example 1. Fig.

As shown in FIG. 5, the organic light emitting diode of Example 1 exhibited a maximum external quantum efficiency of 37.28%, an external quantum efficiency of 36.92% at a luminance of 1000 nits, and an external quantum efficiency of 31.28% at a luminance of 10,000 nits. The performance of the organic light emitting diode of Example 1, which exhibits an external quantum efficiency of 30% or more even at a high luminance, is the best performance in the world as it is known to date. As is known, the conventional organic light emitting diode device has a maximum external quantum efficiency of 29%, and the conventional red organic light emitting diode device has a maximum external quantum efficiency of only 26%.

As shown in FIG. 8, the organic light emitting diode of Comparative Example 1 had a maximum external quantum efficiency of 29.1% and an external quantum efficiency of 27.8% at a luminance of 10,000 nits. This performance is much lower than that of the organic light emitting diode of Example 1.

From these results, it can be seen that the combination of NPB, B3PYMPM and Ir (mphmq) ₂ tmd for the light emitting layer significantly improves the horizontal orientation rate of the dopant in the light emitting layer and thus the organic light emitting diode has significantly improved external quantum efficiency. The effect can be seen.

Further, a combination of a dopant containing a host and an Ir (mphmq) ₂ tmd-based phosphor including a hole transporting material and an electron transporting material for forming an exciplex for a light emitting layer is characterized in that the horizontal orientation ratio of the dopant in the light emitting layer is greatly improved So that the organic light emitting diode has a significantly improved external quantum efficiency. &Quot;

Claims (9)

An anode layer;
A host including a hole transporting material and an electron transporting material for forming an exciplex as a light emitting layer located on the anode layer; And Ir (mphmq) ₂ tmd-based phosphorescent material; And
And a cathode layer disposed on the light emitting layer,
Organic light emitting diode. 2. The organic electroluminescent device according to claim 1, wherein the host is a hole transport material: electron transport material pair which forms an exciplex, NPB: B3PYMPM, TCTA: B3PYMPM, TCTA: TPBi, TCTA: 3TPYMB, TCTA: BmPyPB, TCTA: BSFM, CBP : B3PYMPM, or NPB: BSFM. The organic light emitting diode according to claim 1, wherein the content of the electron transporting material in the light emitting layer is 50 to 150 mol based on 100 mol of the hole transporting material. The method of claim 1, wherein in the light-emitting layer, the Ir (mphmq) ₂ content of tmd-based phosphors, the hole transport material, a total weight of 100 wt of the electron transport material and the Ir (mphmq) ₂ tmd based phosphor %, Based on the total weight of the organic light-emitting diode. The organic light emitting diode according to claim 1, wherein the organic light emitting diode further comprises at least one of a hole transporting layer and a hole injection layer between the anode layer and the light emitting layer. The organic light emitting diode according to claim 1, wherein the organic light emitting diode further comprises at least one of an electron transport layer and an electron injection layer between the cathode layer and the light emitting layer. The organic light-emitting diode according to claim 6, wherein the electron transport layer further comprises n-dopant. 8. A lighting comprising the organic light emitting diode according to any one of claims 1 to 7. A display device comprising the organic light emitting diode according to any one of claims 1 to 7.

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