KR20130070771A - Organic light emitting diodes - Google Patents

Abstract

PURPOSE: An organic light emitting diode is provided to improve color stability, by arranging phosphor material and fluorescent material in one stack with a hybrid structure. CONSTITUTION: A first hole transport layer (221a) is located on top of a first electrode. A first light emitting film (223a) is located on top of the first hole transport layer A first electron transport layer (224a) is located on top of the first light emitting film. A charge generation film is located on top of the first electron transport layer. A second electrode is located on top of a second electron transport layer.

Description

[0001] The present invention relates to organic light emitting diodes

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting device, and more particularly, to an organic light emitting device having improved color reproducibility, luminous efficiency, and lifetime.

Until recently, CRT (cathode ray tube) was mainly used as a display device. However, a flat panel display device such as a plasma display panel (PDP), a liquid crystal display device (LCD), and an organic light emitting diode (OLED) Have been widely studied and used.

Among the above flat panel display devices, an organic light emitting element (hereinafter referred to as OLED) is a self-light emitting element, and a backlight used in a liquid crystal display device which is a non-light emitting element is not required.

In addition, it has a better viewing angle and contrast ratio than liquid crystal display devices, is advantageous in terms of power consumption, can be driven by DC low voltage, has a fast response speed, is resistant to external impacts due to its solid internal components, It has advantages.

Particularly, since the manufacturing process is simple, it is advantageous in that the production cost can be saved more than the conventional liquid crystal display device.

The OLED is a self-luminous element that emits light through the organic electroluminescent diode, and the organic electroluminescent diode emits light through the organic electroluminescent phenomenon.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a band diagram of an organic light emitting diode having an emission principle based on a general organic light emitting phenomenon.

As shown in the figure, the organic light emitting diode 10 includes an anode and a cathode 21, a hole transport layer (HTL) 33 located therebetween, and an electron transport layer And an emission material layer (EML) 40 interposed between the hole transport film 33 and the electron transport film 35.

A hole injecting layer (HIL) 37 is interposed between the anode electrode 21 and the hole transporting layer 33 to improve the luminous efficiency. The cathode electrode 25 and the electron transporting layer 35 are interposed between the anode electrode 21 and the hole transporting layer 33, An electron injection layer (EIL) 39 is interposed therebetween.

When the positive and negative voltages are applied to the anode electrode 21 and the cathode electrode 25, the organic light emitting diode 10 has the positive holes of the anode electrode 21 and the positive electrode of the cathode electrode 25, Electrons are transported to the light-emitting film 40 to form excitons. When the excitons are transited from the excited state to the ground state, light is generated and is emitted by the light-emitting film 40 in the form of visible light.

Recently, the organic light emitting diode 10 has been developed a hybrid type white organic light emitting diode 10 using a fluorescent material and a phosphor at the same time, the hybrid type white organic light emitting diode 10 is a light emitting film ( 40), blue (B) fluorescent material and yellow (Y) and green (G) phosphors are mixed to realize white light emission.

However, in order to realize white light, the light emission method of mixing three wavelengths of blue (B), green (G), and red (R) is ideal, so yellow (Y) and green (G) are used instead of red (R). Since white is implemented by using, the transmittance of light in the red (R) wavelength band after the color filter is low, and thus the color reproduction rate is low.

Therefore, in recent years, OLEDs have been proposed to realize white (W) emission through phosphors mixed with blue (B) type supermaterials, red (R) dopants, and green (G) dopants, but dopants have their own characteristics. As a result, the red (R) dopant and the green (G) dopant have different lifespans, and color shifts occur during continuous use.

SUMMARY OF THE INVENTION It is a first object of the present invention to provide an OLED capable of significantly increasing lifetime and efficiency and satisfying a color reproduction rate.

The second object is to improve the efficiency of the process.

In order to achieve the above-mentioned object, the present invention provides a plasma display panel comprising: a first electrode; A first hole transport layer located above the first electrode; A first light emitting film on the first hole transport film; A first electron transport film located above the first light emitting film; A charge generation film located above the first electron transport film; A second hole transport film, a second light emitting film, a third light emitting film, and a second electron transport film sequentially positioned on the charge generation film; And a second electrode disposed on the second electron transport layer, wherein each of the first to third light emitting films has a light emission characteristic of blue, yellow green, and red. Provided is an element.

In this case, the first light emitting film is a light emitting film doped with a yellow green (YG) phosphorescent dopant, the second light emitting film is a light emitting film doped with a blue (B) fluorescent dopant, and the third light emitting film is a red (R) fluorescent dopant Is a doped light emitting film, wherein the first light emitting film is a light emitting film doped with a blue (B) fluorescent dopant, and the second light emitting film is a light emitting film doped with a yellow green (YG) phosphorescent dopant. The film consists of a light emitting film doped with a red (R) fluorescent dopant.

The red has a spectral wavelength band of 550 nm to 650 nm, and the energy level of the second hole transport layer is higher than the triplet excited state energy level of the second emission layer.

The third emission layer may include a first region in which a red (R) dopant and a host are mixed and deposited, and second and third regions in which a host is deposited on both sides of the first region. The host of the second light emitting layer overlaps with the deposited region.

A hole injection film is interposed between the first electrode and the first hole transport film, and an electron injection film is interposed between the second electrode and the second electron transport film.

As described above, according to the present invention, a first stack including a first light emitting film including a dopant of a blue (B) fluorescent component, a second light emitting film including a dopant of a yellow green (YG) phosphorescent component, and red By forming a second stack including a third light emitting film containing a dopant of the fluorescent component (R), the light emitting characteristics of blue (B), yellow green (YG) and red (R) can be realized while having a two stack structure. In addition, there is an effect that can improve the color reproduction rate when applying the color filter.

In addition, the white OLED of the present invention is arranged in a hybrid structure in which phosphors and fluorescent materials are located in one stack, thereby improving color stability, lowering power consumption, and organic electroluminescence Since the internal quantum efficiency of the triplet state of the diode is 75%, it is possible to improve the luminous efficiency and lifetime of the white OLED.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a band diagram of an organic light emitting diode having an emission principle by a general organic light emitting phenomenon. FIG.
Figure 2 schematically illustrates a cross-section of an OLED according to an embodiment of the present invention.
3 is a simplified cross-sectional view of an organic light emitting diode according to a second embodiment of the present invention.
FIG. 4 is a band diagram of the organic light emitting diode of FIG. 3; FIG.
5 is a simplified cross-sectional view of an organic light emitting diode according to a second embodiment of the present invention.
FIG. 6 is a band diagram of the organic light emitting diode of FIG. 5. FIG.
Figure 7 is a graph measuring the emission spectrum according to the wavelength change of the organic light emitting diode according to the embodiment of the present invention.
8A is a cross-sectional view schematically illustrating a process of depositing a third light emitting film according to a second embodiment of the present invention;
FIG. 8B is a simplified cross-sectional view of an organic light emitting diode including a third light emitting film formed by FIG. 8A.
9 is a simplified view showing a cross-sectional structure of an organic light emitting diode including a third light emitting film according to an embodiment of the present invention.
10A is a cross-sectional view schematically illustrating a process of depositing a second light emitting film and a third light emitting film according to a second embodiment of the present invention;
FIG. 10B is a simplified cross-sectional view of the organic light emitting diode formed by FIG. 10A.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.

2 schematically shows a cross section of an OLED.

As shown in the figure, a plurality of driving thin film transistors DTr and organic electroluminescent diodes E are formed in the pixel region P of the OLED 100 according to the present invention.

In more detail, the semiconductor layer 103 is formed on the pixel region P of the first substrate 101 of the OLED 100, and the semiconductor layer 103 is made of silicon, and the center portion thereof is an active channel forming a channel. The source and drain regions 103a and 103c doped with a high concentration of impurities on both sides of the region 103b and the active region 103b.

The gate insulating layer 105 is formed on the semiconductor layer 103.

The gate electrode 107 and the gate wiring extending in one direction are formed on the gate insulating film 105 in correspondence with the active region 103b of the semiconductor layer 103 and not shown in the drawing.

The first interlayer insulating film 109a and the gate insulating film 105 under the first interlayer insulating film 109a are formed on the upper surface of the gate electrode 107 and the gate wiring (not shown) And first and second semiconductor layer contact holes 111a and 111b that respectively expose source and drain regions 103a and 103c located on both sides of the semiconductor layer 103b.

Next, upper portions of the first interlayer insulating film 109a including the first and second semiconductor layer contact holes 111a and 111b are separated from each other by a source exposed through the first and second semiconductor layer contact holes 111a and 111b, And source and drain electrodes 113 and 115 which are in contact with the source and drain regions 103a and 103c, respectively.

And a drain contact hole 117 exposing the drain electrode 115 to the upper portion of the first interlayer insulating film 109a exposed between the source and drain electrodes 113 and 115 and the two electrodes 113 and 115, An insulating film 109b is formed.

At this time, the semiconductor layer 103 including the source and drain electrodes 113 and 115 and the source and drain regions 103a and 103c contacting the electrodes 113 and 115 and the gate insulating film The gate electrode 105 and the gate electrode 107 constitute a driving thin film transistor DTr.

At this time, although not shown in the drawing, data lines (not shown) are formed which cross the gate wiring (not shown) and define the pixel region P. The switching thin film transistor (not shown) has the same structure as the driving thin film transistor DTr and is connected to the driving thin film transistor DTr.

The switching and driving thin film transistor (not shown) DTr is shown as an example of a top gate type in which the semiconductor layer 103 is a polysilicon semiconductor layer. As a variation thereof, the amorphous Or may be formed of a bottom gate type made of silicon nitride.

The first electrode 211, the organic light emitting layer 213, and the second electrode 215 constituting the organic electroluminescent diode E are sequentially formed on the second interlayer insulating film 109b, Respectively.

Here, the first electrode 211 is connected to the drain electrode 115 of the driving thin film transistor DTr through the drain contact hole 117 of the second interlayer insulating film 109b.

In this case, the first electrode 211 is formed of indium-tin-oxide (ITO), which is a relatively high work function value, to serve as an anode electrode, and the second electrode 215 is formed of a cathode cathode is made of a metal material having a relatively low work function value.

Here, the organic light emitting layer 213 is a hole transport film (221a, 221b in Figure 3), a hole injection film (222 in Figure 3), a light emitting film (223a, 223b, 223c in Figure 3), an electron transport film (in Figure 3 224a, 224b) and an electron injection film (225 in FIG. 3).

In addition, since the light emitted from the organic light emitting layer 213 must pass through the second electrode 215, the second electrode 215 has a thick transparent conductive material on the semitransparent metal film on which a thin metal material having a low work function is deposited. It may be made of a double layer structure to be deposited.

When a predetermined voltage is applied to the first electrode 211 and the second electrode 215 in accordance with a selected color signal, the OLED 100 emits light from the holes injected from the first electrode 211 and the holes injected from the second electrode 215 The excited electrons are transported to the organic light emitting layer 213 to form an exciton. When the excitons transit from the excited state to the ground state, light is emitted and emitted in the form of visible light.

At this time, since the light emitted from the organic light emission is passed through the second electrode 215 to the outside, the OLED 100 implements an image by the top emission method.

The first electrode 211 is formed for each pixel region P and a bank 119 is located between the first electrodes 211 formed for each pixel region P. [

The OLED 100 of the present invention is improved in color reproducibility compared to the conventional, and also the luminous efficiency and lifetime of the OLED 100 is also improved compared to the conventional, which is the organic light emitting layer (213) of the organic light emitting diode (E) This is because the luminous efficiency is improved.

3 is a simplified cross-sectional view of an organic light emitting diode according to a second embodiment of the present invention, and FIG. 4 is a band diagram of the organic light emitting diode of FIG. 3.

As shown in detail, the organic light emitting layer 213 according to the first embodiment of the present invention will be described in more detail. The organic light emitting diode E may have a first electrode 211 as an anode and a second electrode as a cathode. 215 and a first stack 229a, a charge generation layer CGL 227, and a second stack 229b stacked between the first electrode 211 and the second electrode 215. The organic light emitting layer 213 is formed.

Here, holes and electrons are formed by the charge generation film 227 through the adjacent second hole transport film 221b and the first electron transport film 224a of the first and second stacks 229a and 229b, respectively. 223a, 223b, and 223c.

At this time, the charges generated in the charge generation film 227 are combined with the holes and electrons injected from the first electrode 211 and the second electrode 215 to emit light.

At this time, the charge generating film 227 can use various organic materials having strong electron donor and electron acceptor characteristics. Basically all materials used for P-type and N-type bonding are available.

The charge generation film 227 is preferably formed of P-type and N-type organic semiconductors in order to facilitate the deposition and improve the interfacial characteristics.

A P-type organic semiconductor is a donor capable of absorbing light to form an exciton and to separate electrons into holes and electrons at junctions with N-type organic semiconductors. At this time, the N type organic semiconductor can be a material that can accept electrons easily, that is, a material that can be easily reduced as an acceptor.

The first stack 229a may include a first hole transport layer (HTL) 221a, a first emission layer 223a, and a first electron between the first electrode 211 and the charge generation layer 227. An electron transport layer (ETL) 224a is stacked in this order, and the second stack 229b is sequentially disposed between the charge generation film 227 and the second electrode 215, and the second hole transport film 221b, The second light emitting film 223b, the third light emitting film 223c, and the second electron transport film 224b are stacked.

In this case, a first hole injection layer (HIL) 222 is interposed between the first electrode 211 and the first hole transport layer 221a to improve the luminous efficiency, and the second electrode 215 and the first electrode are interposed therebetween. A second electron injection layer EIL 225 is interposed between the two hole transport films 224b.

Here, the first light emitting film 223a is formed of a single light emitting film formed by doping phosphorescent yellow green (YG) dopant (YG) dopant on one host, and the second light emitting film 223b is blue on one host. (B) A light emitting film including a dopant of a fluorescent component, and the third light emitting film 223c includes a light emitting film including a dopant of a red (R) fluorescent component in one host.

That is, the organic light emitting diode E of the present invention has light emission characteristics of blue (B), yellow green (YG), and red (R).

Therefore, the first light emitting film 223a, the second light emitting film 223b, and the third light emitting film 223c when the white OLED (100 in FIG. 2) including the organic light emitting diode E of the present invention is driven. White light is realized by mixing the light emitted.

In this case, since the red (R) fluorescent component has a spectral wavelength band of 550 to 650 nm, the white light implemented through the white OLED 100 of the present invention has a wavelength band of blue (B), red (R), and green (G). To implement white light having a wide wavelength range of 450 ~ 650nm including.

In addition, the yellow green (YG) light emitting characteristics are high luminous characteristics, it is possible to improve the luminous characteristics of the white light implemented from the white OLED 100 according to an embodiment of the present invention.

On the other hand, the organic electroluminescent diode (E) of the present invention can be arranged in a hybrid structure in which phosphors and fluorescent materials are located in one stack (229a, 229b), it is possible to improve color stability and lower power consumption. .

In particular, since the internal quantum efficiency of the triplet state of the organic light emitting diode E may be 75%, the luminous efficiency and lifespan of the white OLED 100 may be improved.

5 is a simplified cross-sectional view of an organic light emitting diode according to a second embodiment of the present invention, and FIG. 6 is a band diagram of the organic light emitting diode of FIG. 5.

As shown in detail, the organic light emitting layer 213 according to the second embodiment of the present invention will be described in more detail. The organic light emitting diode E may have a first electrode 211 as an anode and a second electrode as a cathode. 215 and a first stack 229a, a charge generation layer CGL 227, and a second stack 229b stacked between the first electrode 211 and the second electrode 215. The organic light emitting layer 213 is formed.

Here, holes and electrons are formed by the charge generation film 227 through the adjacent second hole transport film 221b and the first electron transport layer 224a of the first and second stacks 229a and 229b, respectively. , 223b, 223c).

At this time, the charges generated in the charge generation film 227 are combined with the holes and electrons injected from the first electrode 211 and the second electrode 215 to emit light.

At this time, the charge generating film 227 can use various organic materials having strong electron donor and electron acceptor characteristics. Basically all materials used for P-type and N-type bonding are available.

In order to facilitate deposition and to improve interfacial properties, the charge generation film is preferably formed of P-type and N-type organic semiconductors.

P-type organic semiconductor absorbs light to form an exciton (exciton), and is a donor (donor) can be good electrons are separated into holes and electrons at the junction (junction) with the N-type organic semiconductor. . At this time, the N type organic semiconductor can be a material that can accept electrons easily, that is, a material that can be easily reduced as an acceptor.

The first stack 229a includes a first hole transport film 221a, a second light emitting film 223b, and a first electron transport film 224a between the first electrode 211 and the charge generation film 227. The second stack 229b is sequentially stacked, and the second hole transport film 221b, the first light emitting film 223a, and the third light emitting film are sequentially disposed between the charge generation film 227 and the second electrode 215. The second electron transport film 224b is stacked.

At this time, the first hole injection film 222 is interposed between the first electrode 211 and the first hole transport film 221a to improve the luminous efficiency, and the second electrode 215 and the second hole transport film ( A second electron injection film 225 is interposed between 224b.

Here, a second light emitting film 223b including a light emitting film including a dopant of blue (B) fluorescent material in one host is included in the first stack 229a, and phosphorescent yellow green dopant (phosphorescence yellow) in one host is included. The second stack 229b includes a first light emitting film 223a formed by doping green and a third light emitting film 223c including a dopant of a red (R) fluorescent component in one host.

That is, the organic light emitting diode E of the present invention has light emission characteristics of blue (B), yellow green (YG), and red (R).

Therefore, the first light emitting film 223a, the second light emitting film 223b, and the third light emitting film 223c when the white OLED (100 in FIG. 2) including the organic light emitting diode E of the present invention is driven. White light is realized by mixing the light emitted.

In this case, since the red (R) fluorescent component has a spectral wavelength band of 550 to 650 nm, the white light implemented through the white OLED 100 of the present invention has a wavelength band of blue (B), red (R), and green (G). To implement white light having a wide wavelength range of 450 ~ 650nm including.

In addition, the yellow green (YG) light emitting characteristics are high luminous characteristics, it is possible to improve the luminous characteristics of the white light implemented from the white OLED 100 according to an embodiment of the present invention.

In the organic light emitting diode (E) of the present invention, the third light emitting film 223c of the second stack 229b is formed of a red (R) light emitting film made of a fluorescent material, and the first light emitting film 223a is yellow. The green (YG) light emitting film is made of a phosphor so that recombination of holes and electrons is performed in the third light emitting film 223c made of the red (R) light emitting film, and the triple generated in the third light emitting film 223c. The anti-exciton is moved to the first light emitting film 223a made up of the phosphor film as much as possible using energy transfer to obtain phosphorescence emission of yellow green (YG), thereby improving luminous efficiency.

That is, when holes and electrons form excitons in the light emitting films 223a and 223c, a singlet state and a triplet state are generated at a ratio of 3: 1. Here singlet excitons can shine and transition to the ground state, called fluorescence. However, it is forbidden that the triplet excitons shine and transition to the singlet ground state.

However, due to perturbation such as spin-orbit coupling, triplet excitons can also transition to light, which is called phosphorescence.

Here, the phosphorescence is due to the recombination of the holes and the electrons, all excitons formed in either a singlet or triplet excited state can participate in the light emission.

In comparison, only about 25% of excitons in fluorescent elements can produce fluorescent luminescence resulting from a singlet excited state. The remaining excitons produced in the lowest triplet excited state in the fluorescent device cannot be converted to the higher energy singlet excited states in which fluorescence is generated.

Accordingly, the organic light emitting diode E of the present invention moves the triplet excitons generated from the third light emitting film 223c made of the fluorescent light emitting film to the first light emitting film 223a made of the phosphorescent film, thereby producing yellow green (YG). By obtaining phosphorescence emission, the luminous efficiency of the organic light emitting diode E can be improved.

At this time, the second hole transport film 221b and the second electron transport film 224b of the present invention are set to have an energy level higher than the energy level of the excited state of the triplet exciton of the first emission film 223a. The second hole transport film 221b is preferably set to be about 0.001 to 0.5 eV higher than the energy level of the excited state of the triplet exciton of the first light emitting film 223a.

Since the energy level of the second hole transport film 221b and the second electron transport film 224b is higher than that of the first light emitting film 223a, the triplet excitons of the first light emitting film 223a are the second hole transport film ( 221b and the second electron transport film 224b may be prevented from falling in luminous efficiency.

The first electron transport film 224a and the first hole transport film 221a are set to an energy level of 0.001 to 0.5 eV higher than the energy level of the excited state of the triplet triplet exciton of the first emission film 223a. It is preferable.

As described above, the first and second hole transport films 221a and 221b and the first and second electron transport films 224a and 224b on the upper and lower interface sides of the first and third light emitting films 223a and 223c, respectively. By raising the energy level, the singlet excitons and triplet excitons are prevented from being moved to the upper and lower interfaces of the first and third light emitting films 223a and 223c, so that they can be used for light emission as much as possible.

Accordingly, the first and second hole transport films 221a and 221b and the first and second electron transport films 224a and 224b have high triplet energy, thereby eliminating triplet excitons. It is destroyed by triplet-triplet collision annihilation.

Thus, delayed fluorescence by singlet excitons has a much longer lifetime than the fluorescence lifetime of directly excited singlet excitons. By such delayed fluorescence, the luminous efficiency of the organic light emitting diode E can be further improved.

Therefore, in the present invention, the organic light emitting diode (E) is 20% or more improved in luminous efficiency compared to the conventional, and the lifetime is also increased by 50% or more within the same luminance.

In particular, the organic light emitting diode (E) of the present invention includes blue (B), yellow green (YG), which are emitted from the first light emitting film 223a, the second light emitting film 223b, and the third light emitting film 223c. By implementing the white light by mixing the light of the red (R), the color reproducibility is improved.

7 is a graph illustrating emission spectra according to wavelength changes of the organic light emitting diode according to the exemplary embodiment of the present invention.

Here, C1 represents a wavelength spectrum of an organic light emitting diode which emits white (W) light by mixing a blue (B) phosphor and yellow (Y) and green (YG) phosphors, and C2 denotes the present invention. According to the embodiment of the wavelength spectrum of the organic light emitting diode (E of FIG. 5) of the blue (B) and red (R) phosphor and the yellow green (YG) phosphor to achieve a white (W) emission to implement Indicated.

Referring to FIG. 7, it can be seen that C1 does not implement the spectrum of the red (R) wavelength band.

When white light emitted from the organic light emitting diode passes through the red (R), green (G), and blue (B) color filters (not shown), the transmittance of the light passing through the red (R) color filter is low. The color of red (R) is lost a lot.

Therefore, color reproduction rate is low.

On the other hand, by further including the red (R) fluorescent material as in the embodiment of the present invention of C2, it can be seen that the blue (B), yellow green (YG) and red (R) wavelength bands have even and high peak values Can be.

Therefore, the color reproducibility in the color filter (not shown) is improved.

In particular, since the red (R) fluorescent component according to the embodiment of the present invention has a spectral wavelength band of 550 to 650 nm, the white light implemented through the white OLED (100 of FIG. 2) according to the embodiment of the present invention is blue ( B), white light having a broad wavelength range of 450 to 650 nm including all wavelengths of red (R) and green (G).

Meanwhile, the first to third light emitting films 223a, 223b, and 223c according to the embodiment of the present invention are formed through a vacuum thermal evaporation process. In the vacuum thermal evaporation process, an organic material having a desired color is deposited with an outlet. After being placed in a circle (not shown), the evaporation source (not shown) is heated in a chamber (not shown) where a vacuum is maintained to release the evaporated organic material through an outlet (not shown), whereby the released organic material is transferred to a substrate. By being deposited on (not shown), the first to third light emitting films 223a, 223b, and 223c are formed.

In this case, the first to third light emitting films 223a, 223b, and 223c are usually configured as a host-dopant system. In general, the host has a high energy gap and the excitons formed in the host undergo energy transfer to dopants having a lower energy gap.

That is, the first light emitting film 223a is formed by doping phosphorescent yellow green (YG) dopant (YG) dopant together in one host, and the second light emitting film 223b implements the blue (B) light emitting property. For example, one host includes a dopant of a blue (B) fluorescent component, and the third emission layer 223c includes a dopant of a red (R) fluorescent component in one host.

At this time, the host of the first light emitting film 223a and the third light emitting film 223b may be different species, or may be of the same species.

8A is a cross-sectional view schematically illustrating a deposition process of a third light emitting film according to a second embodiment of the present invention. FIG. 8B is a simplified cross-sectional structure of an organic light emitting diode including a third light emitting film formed by FIG. 8A. Figure is shown.

Here, the vacuum thermal deposition method is installed in the crucibles (310a, 310b, 310c) containing the organic matter (330a, 330b, 340) of the powder state, and a heater (heater) for heating sublimation of the organic matter is installed in the crucibles (310a, 310b, 310c) It is carried out by the vacuum deposition equipment (not shown).

As shown in Figure 8a, the vacuum deposition equipment is an essential component of the chamber 300 defining the closed reaction zone (A), the crucible unit 310 is provided therein.

Here, the crucible unit 310 is composed of first to third crucibles (310a, 310b, 310c), the second crucible (310b) located in the center contains a dopant 340 of the red (R) fluorescent component, The first and third crucibles 310a and 310c positioned at both sides of the second crucible 310b contain first and second hosts 330a and 330b, respectively.

Sides of each of the first to third crucibles 310a, 310b, and 310c are provided with a heater (not shown) for heating and subliming the dopant 340 of the red (R) fluorescent component and the hosts 330a and 330b. do.

Here, the reaction region A is always provided in a vacuum state and is provided with a substrate 101 on which a first electrode (211 of FIG. 5), etc., which is an anode electrode, is disposed to face the crucible unit 310.

In addition, a mask M having an opening G is provided in a region corresponding to a region where the dopant 340 and the hosts 330a and 330b are to be deposited on the substrate 101.

At this time, the substrate 101 is fixed by the substrate holder 350, and moves in the horizontal direction.

That is, the vacuum deposition apparatus of the present invention is a scan type in which the substrate 101 is horizontally moved and deposition is performed while the first to third crucibles 310a, 310b, and 310c are fixed.

Accordingly, the dopant 340 of the red (R) fluorescent component vaporized from the first to third crucibles 310a, 310b, and 310c and the first and second hosts 330a and 330b have different deposition regions D1. , D2, D3).

The dopant 340 of the red (R) fluorescent component evaporated from the second crucible 310b has a first deposition region D1, and the first host 330a evaporated from the first crucible 310a is a second deposition. The second host 330b having the region D2 and evaporated from the third crucible 310c has the third deposition region D3.

Therefore, as shown in FIG. 8B, the organic light emitting diode E according to the embodiment of the present invention has a third emission layer 223c and a second deposition region D2 on which the first host 330a is deposited. The third deposition region D3 on which the second host 330b is deposited and the first deposition region D1 on which the dopant 340 of the red (R) fluorescent component is deposited are deposited.

In this case, since a region in which the first deposition region D1 and the second deposition region D2 and the first deposition region D1 and the third deposition region D3 overlap with each other is generated, the third emission layer 223c Red between the first host region h1 on which the first host 330a is deposited, the second host region h2 on which the second host 330b is deposited, and the first and second host regions h1 and h2. The dopant 340 of the (R) fluorescent component and the first and second hosts 330a and 330b are mixed to form a red (R) dopant and a host region (R_DH).

The third emission layer 223c emits light of the red R through the red R dopant and the host region R_DH.

FIG. 9 is a simplified cross-sectional view of an organic light emitting diode including a third light emitting film according to an embodiment of the present invention.

As shown in FIG. 9, the organic light emitting diode E according to the embodiment of the present invention has a third emission layer 223c of the second deposition region D2 and the red (R) fluorescent component on which the host is deposited. The dopant is formed of a first deposition region D1.

In this case, since a region in which the first deposition region D1 and the second deposition region D2 overlap each other occurs, the third emission layer 223c may include a dopant and a host of the host region h and the red (R) fluorescent component. Is composed of a mixed red (R) dopant and a host region (R_DH).

The third emission layer 223c emits light of the red R through the red R dopant and the host region R_DH.

This can be formed by making the crucible unit 310 of FIG. 8A of the vacuum thermal evaporation apparatus consist of only the first crucible including the dopant of the red (R) fluorescent component and the second crucible including the host.

In addition, the host of the second light emitting film 223b and the third light emitting film 223c of the present invention may be formed of the same species, which will be described in more detail.

FIG. 10A is a cross-sectional view schematically illustrating a process of depositing a second light emitting film and a third light emitting film according to a second embodiment of the present invention, and FIG. 10B is a simplified cross-sectional view of the organic light emitting diode formed by FIG. 10A. One drawing.

As shown in Figure 10a, the vacuum deposition equipment is an essential component of the chamber 300 defining the closed reaction zones (A1, A2), the first and second crucible units (310, 320) therein. ) Is provided.

Here, the reaction zone is divided into first and second reaction zones A1 and A2, and the first and second crucible units 310 and 320 are provided in the first and second reaction zones A1 and A2, respectively. In addition, the first reaction region A1 is provided with a substrate 101 on which a first electrode (211 of FIG. 5) and the like, which are anode electrodes, are provided to face the first crucible unit 310.

In addition, a mask M having an opening G is provided in a region corresponding to a region where the dopants 340a and 340b and the hosts 330a, 330b and 330c are to be deposited on the substrate 101.

Here, the first crucible unit 310 is composed of the first to third crucibles (310a, 310b, 310c), the second crucible unit 320 is composed of the first and second crucibles (320a, 320b), The second crucible 310b located in the center of the first crucible unit 310 located in the first reaction region A1 contains a dopant 340a of a yellow green (YG) phosphorescent component, and the second crucible 310b. The first and third crucibles 310a and 310c located at both sides of the first and second crucibles 310a and 310c respectively contain the first and second hosts 330a and 330b.

In addition, the first crucible 320a of the second crucible unit 320 positioned in the second reaction region A2 contains the dopant 340b of the red (R) fluorescent component, and one side of the first crucible 320a. The second crucible 320b located at includes the third host 330c.

At this time, the substrate 101 is fixed by the substrate holder 350, and moves in the horizontal direction.

That is, in the vacuum deposition apparatus of the present invention, the substrate 101 is horizontally moved in the first and second reaction regions A1 and A2, and the deposition is performed while the first and second crucible units 310 and 320 are fixed. It is a scan type.

Therefore, in the first reaction region A1, the dopant 340a of the yellow green (YG) phosphorescent component evaporated from the second crucible 310b of the first crucible unit 310 on the substrate 101 is formed in the first deposition region. The first host 330a deposited in D1 and evaporated from the first crucible 310a is deposited in the second deposition region D2, and the second host 320b evaporated from the third crucible 310c is It is deposited in the third deposition region D3.

In addition, the substrate 101 is moved to the second reaction region A2 so that the dopant 340b of the red (R) fluorescent component evaporated from the first crucible 320a of the second crucible unit 320 is deposited fourth. The third host 330c deposited in the region D4 and evaporated from the second crucible 320b is deposited in the fifth deposition region D5.

Accordingly, as shown in FIG. 10B, the organic light emitting diode E according to the embodiment of the present invention has a first emission layer 223a and a second deposition region D2 on which the first host 330a is deposited. And a third deposition region D3 on which the second host 330b is deposited, and a first deposition region D1 on which the dopant 340a of the yellow green (YG) phosphorescent component is deposited. The fourth deposition region D4 on which the dopant 340b of the red (R) fluorescent component is deposited and the fifth deposition region D5 on which the third host 330c is deposited are formed on one side of the substrate.

In this case, since a region in which the first deposition region D1 and the second deposition region D2 and the first deposition region D1 and the third deposition region D3 overlap with each other is generated, the first emission layer 223a Yellow between the first host region h1 on which the first host 330a is deposited, the second host region h2 on which the second host 330b is deposited, and the first and second host regions h1 and h2. The dopant 340a of the green (YG) phosphorescent component and the first and second hosts 330a and 330b are mixed to be formed of a yellow green (YG) dopant and a host region (GY_DH).

The first emission layer 223a emits light of the yellow green YG through the yellow green YG dopant and the host region GY_DH.

In addition, the third emission layer 223c includes a red (R) dopant and a host region (R_DH), in which the dopant 340b of the red (R) fluorescent component and the third host 330c are mixed, and the third host ( 330c is formed of the deposited third host region h3.

In this case, the red (R) dopant and the host region (R_DH) of the second host region h2 of the first emission layer 223a and the third emission layer 223c may be deposited to overlap each other.

Accordingly, the second host 330b of the second host region h2 of the first emission layer 223a may be deposited on the red R dopant and the host region R_DH of the third emission layer 223c.

As described above, the white OLED (100 of FIG. 2) of the present invention has a two-stack (229a, 229b) structure and can implement the light emission characteristics of blue (B), yellow green (YG) and red (R), color When the filter is applied, color reproduction can be improved.

In addition, the white OLED (100 of FIG. 2) of the present invention may be disposed in a hybrid structure in which phosphors and fluorescent materials are located in one stack 229b, thereby improving color stability and lowering power consumption. Since the internal quantum efficiency of 75%, which is a triplet state of the organic light emitting diode E, can be used, the luminous efficiency and lifetime of the white OLED (100 of FIG. 2) can be improved.

The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

211: first electrode, 215: second electrode,
213: organic light emitting layer (221a, 221b: first and second hole transport film, 222: hole injection film, 223a, 223b, 223c: first to third light emitting film, 224a, 224b: first and second electron transport, 225: electron injection film)
229a, 229b: first and second stacks
E: Organic light emitting diode

Claims (8)

A first electrode;
A first hole transport layer located above the first electrode;
A first light emitting film on the first hole transport film;
A first electron transport film located above the first light emitting film;
A charge generation film located above the first electron transport film;
A second hole transport film, a second light emitting film, a third light emitting film, and a second electron transport film sequentially positioned on the charge generation film;
The second electrode located on the second electron transport film
And each of the first to third light emitting films has blue, yellow green, and red light emitting characteristics.
The method of claim 1,
The first light emitting layer is a light emitting layer doped with a yellow green (YG) phosphorescent dopant, the second light emitting layer is a light emitting layer doped with a blue (B) fluorescent dopant, and the third light emitting layer is a red (R) fluorescent dopant doped. An organic light emitting device comprising a light emitting film.
The method of claim 1,
The first light emitting film is a light emitting film doped with a blue (B) fluorescent dopant, and the second light emitting film is a light emitting film doped with a yellow green (YG) phosphorescent dopant, and the third light emitting film is doped with a red (R) fluorescent dopant. An organic light emitting device comprising a light emitting film.
The method of claim 1,
The red is an organic light emitting device having a spectral wavelength band of 550 ~ 650nm.
The method of claim 3, wherein
The second hole transport film has an energy level higher than the triplet excited state energy level of the second light emitting layer.
The method of claim 1,
The third emission layer includes an organic light emitting device including a first region in which a red (R) dopant and a host are mixed and deposited, and second and third regions in which a host is deposited on both sides of the first region.
The method according to claim 6,
And the third region overlaps with the region where the host of the second emission layer is deposited.
The method of claim 1,
Wherein a hole injection film is interposed between the first electrode and the first hole transporting film, and an electron injecting film is interposed between the second electrode and the second electron transporting film.

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