KR101950827B1 - Organic Light Emitting Device and Method for Manufacturing the Same - Google Patents

Abstract

The present invention relates to an organic light emitting device having a structure in which color mixing of regions where overlapping light emitting layers of different colors are prevented from overlapping, improving color purity of pixels of each color, and improving efficiency of a device, and a method of manufacturing the same, A first electrode formed on the substrate, a second electrode facing the first electrode and spaced apart from the first electrode, and a second electrode spaced apart from the first electrode, A first color light emitting layer formed on the first color pixel and a second color light emitting layer formed on the second color pixel; A first electron transport layer, a light extraction enhancement layer, and a second electron transport layer, which are sequentially stacked, between the light emitting layer and the second electrode; And a common layer between the first electrode and the light emitting layer.

Description

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

The present invention relates to an organic light emitting device, and more particularly, to an organic light emitting device having a structure in which color mixing of regions where overlapping light emitting layers of different colors are prevented to improve color purity of pixels for each color, .

The image display device that realizes various information on the screen is a core technology of the information communication age and it is becoming thinner, lighter, more portable and higher performance. Accordingly, an organic light emitting display device for displaying an image by controlling the amount of light emitted from the organic light emitting layer by using a flat panel display capable of reducing weight and volume, which is a disadvantage of a cathode ray tube (CRT)

The organic light emitting display device is a self-light emitting device using a thin light emitting layer between electrodes and has an advantage that it can be made thin like a paper. The organic light emitting display device is divided into an active matrix capable of being selectively driven by the individual cell driver for each pixel and a passive matrix capable of being controlled on a line-by-line basis.

At this time, the active matrix organic light emitting display device (AMOLED) displays images by arranging pixels composed of three color (R, G, B) pixels in a matrix form. Each pixel includes an organic light emitting diode and a cell driver for driving the organic light emitting diode. The cell driver is composed of at least two thin film transistors connected between a gate line for supplying a scan signal, a data line for supplying a video data signal, and a common power supply line for supplying a common power supply signal so as to drive the anode of the organic light emitting diode do.

The organic light emitting device includes an anode, a hole injection layer (HIL), a hole transport layer (HTL), a light emitting layer, an electron transport layer (ETL), an electron injection layer (ETL) EIL), and a cathode.

It has been suggested that the organic light emitting device is formed by vacuum deposition for each layer. This is a method of vaporizing the material of the layer to be formed in a vacuum chamber and depositing the material on the substrate.

However, when a vacuum chamber is used, the size of the chamber must be at least larger than the size of the substrate on which the vacuum deposition is performed, and it is difficult to ensure sufficient space in the lateral and vertical directions for the substrate in the chamber. It is difficult to keep the chamber in a vacuum condition.

For example, there is a method in which a solution layer is formed on a substrate without a chamber requiring a separate vacuum condition through a soluble process.

However, there is a problem in that each layer of the organic light emitting device is poor in material stability and can not be subjected to a solution process. Particularly, in the case of a blue light emitting material, A method of separating the light emitting material from the red / green light emitting layer and applying the forming process has been proposed.

Such conventional organic light emitting devices have the following problems.

As a hybrid type organic light emitting device, a structure in which a red light emitting layer and a green light emitting layer are formed separately for each pixel, and a blue light emitting layer is commonly formed over all the pixels is known.

However, in this structure, since the blue light emitting layer is formed over all the pixels (BCL (Blue Common Layer Structure) structure), there exists a region overlapping the red light emitting layer and the green light emitting layer, There is a problem of falling.

That is, in a recently-known hybrid type organic light emitting device, a blue light emitting layer overlaps a light emitting layer of a different color, and there is a color mixing effect of light emission at this portion.

Various types of structures have been proposed for lowering the color purity. However, there is a problem that the driving voltage increases when the color purity is improved. Thus, in the hybrid organic light emitting device, a structure in which the driving voltage is lowered and the color purity is improved has been developed I did.

DISCLOSURE Technical Problem The present invention has been devised to solve the problems described above, and it is an object of the present invention to provide an organic light emitting device having a structure in which color mixing of regions overlapping with light emitting layers of different colors is prevented, And a manufacturing method thereof.

According to an aspect of the present invention, there is provided an organic light emitting diode comprising a substrate divided into first to third color pixels, a first electrode formed on the substrate, A first color light emitting layer formed between the first electrode and the second electrode, the first color light emitting layer formed in the first color pixel, and the second color light emitting layer formed in the second color pixel, And a second layer of a third color-light-emitting layer formed on the first color pixel to the third color pixel; and a second electron-transport layer, a light-extraction enhancement layer, and a second An electron transport layer; And a common layer between the first electrode and the light emitting layer.

Here, the light extracting enhancement layer is formed by doping an n-type impurity into the material of the first electron transporting layer and the second electron transporting layer.

The n-type impurity may be an alkali metal, or the n-type impurity may be a substance that enhances electron mobility of the first and second electron transporting layers.

The first electron transporting layer and the second electron transporting layer may be made of the same material or made of different materials.

On the other hand, the second layer, the first electron transporting layer, the light extracting enhancement layer, and the second electron transporting layer of the light emitting layer may be formed as a whole between the first and second electrodes without any region separation.

The light emitting layer may further include a hybrid connection layer between the first layer and the second layer.

The common layer includes a hole transporting layer. In some cases, the common layer may further include a hole injection layer.

It is preferable that the third color light emitting layer is a blue light emitting layer, and the first color light emitting layer and the second color light emitting layer are a color combination light emitting layer that emits white light by mixing with the third color light emitting layer.

In addition, it is preferable that the first layer of the common layer and the light emitting layer is made of a solution material, and the third color light emitting layer, the first electron transporting layer, the light extracting enhancement layer and the second electron transporting layer are made of a low molecular material.

Meanwhile, the substrate may include a thin film transistor array connected to the first electrode.

According to another aspect of the present invention, there is provided an organic light emitting device including a substrate having red, green, and blue pixels defined therein, a first electrode formed on the substrate, A green light emitting layer formed between the first electrode and the second electrode, the red light emitting layer formed on the red pixel, and the green light emitting layer formed on the green pixel; A blue light emitting layer formed in common between the blue light emitting layer and the second electrode, a first electron transporting layer, a light extracting enhancement layer, and a second electron transporting layer sequentially stacked between the blue light emitting layer and the second electrode; And a common layer between the first electrode and the light emitting layer.

Here, the common layer, the red light emitting layer, and the green light emitting layer may be made of a solution material, and the blue light emitting layer, the first electron transporting layer, the light extracting enhancement layer, and the second electron transporting layer may be made of a low molecular material.

According to another aspect of the present invention, there is provided a method of fabricating an organic light emitting diode, comprising: preparing a substrate having first to third color pixels divided therein; forming a first electrode on the substrate, Forming a common layer by a solution process on the first electrode, a first color light-emitting layer in the first color pixel and a second color light-emitting layer in the second color pixel, Forming a third color light emitting layer over the first color pixel to the third color pixel, covering the first color light emitting layer and the second color light emitting layer through a deposition process; Forming a first electron transporting layer, a light extracting enhancement layer, and a second electron transporting layer on the third color light emitting layer sequentially through a deposition process; And forming a second electrode on the second electron transporting layer.

Here, the step of forming the light extraction enhancing layer may be performed by mixing the first electron transporting layer material and the second electron transporting layer material with an n-type impurity and depositing the mixture on the first electron transporting layer.

The solution process for forming the common layer, the first color-light-emitting layer, and the second color-light-emitting layer may be performed by various methods such as inkjet printing, nozzle printing, transferring method, slit coating, gravia printing and thermal jet printing It can be made of any one of them.

The method may further include the step of forming a hybrid connection layer between the layers of the first and second color light-emitting layers and the third color light-emitting layer.

The organic light emitting device of the present invention and the method of manufacturing the same have the following effects.

First, even if the thickness of the common layer between the light emitting layer and the electrode is increased to some extent by the provision of the light extraction enhancement layer, the light extraction efficiency can be improved without increasing the driving voltage of the device.

Second, by providing a hybrid connection layer between the light extraction enhancement layer and the second layer of the blue light emitting layer and the first layer of the red / green light emitting layer at the center of the electron transport layer, the red light emitting layer or the blue light emitting layer, When pure red / green luminescence is performed, the electron / hole recombination ratio of the blue luminescent layer can be limited to prevent the deterioration of color purity.

1 is a cross-sectional view illustrating an organic light emitting device according to a first embodiment of the present invention;
2 is a cross-sectional view illustrating an active matrix organic light emitting display device to which an organic light emitting diode according to a modification of the first embodiment is applied
3 is a cross-sectional view illustrating an organic light emitting device according to a second embodiment of the present invention
4 is a cross-sectional view illustrating an organic light emitting device according to a comparative example
5A and 5B are graphs showing the intensities of light according to the driving voltages applied to the red light emitting layer portion and the green light emitting layer portion in the organic light emitting device of FIG.
6 is a cross-sectional view illustrating an organic light emitting device according to a modification of the first embodiment of the present invention
7A and 7B are graphs showing the intensities of light according to the driving voltages applied to the red light emitting layer portion and the green light emitting layer portion in the organic light emitting device of FIG.

Hereinafter, an organic light emitting device and a method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view illustrating an organic light emitting diode according to a first embodiment of the present invention.

1, the organic light emitting device according to the first embodiment of the present invention includes a TFT substrate 100 in which first to third color pixels are defined in a divided manner, a first electrode (not shown) formed on the TFT substrate 100, A second electrode 148 facing the first electrode 132 and spaced apart from the first electrode 132 and a second electrode 148 formed between the first electrode 132 and the second electrode 148, A first layer of the second color light emitting layer 137 formed on the second color pixel and a second layer of the third color light emitting layer 144 formed on the first color pixel to the third color pixel, A light emitting layer (EML) composed of two layers and a first electron transport layer 1461, a light extraction enhancement layer 1462, and a second electron transport layer (not shown) are sequentially stacked between the light emitting layer (EML) And a first common layer 134 between the first electrode 132 and the light emitting layer (EML).

Here, the TFT substrate 100 is formed with a cell driver including a TFT (thin film transistor) for each pixel.

The first to third color pixels are regularly and repeatedly formed. This regularity can be line-by-line or diagonal.

In the illustrated example, the first color pixel represents a red pixel, the second color pixel represents a green pixel, the third color pixel represents a blue pixel, and the red light emitting layer 136 and the green light emitting layer 137 represent first, And the blue light emitting layer 144 is formed over all the pixels. However, the organic electroluminescent device of the present invention is not limited to such a color combination, but may be changed to other combinations of colors as long as white can be realized by mixing colors of the respective light emitting layers. For example, the third color pixel may be a blue pixel, and the first and second color pixels may be a yellow pixel and a green pixel, respectively.

The red light emitting layer 136 and the green light emitting layer 137 are divided into different color pixels. The red light emitting layer 136 and the green light emitting layer 137 are selectively formed on the first common layer 134, Coating. Here, the red light emitting layer 136 and the green light emitting layer 137 may be a fluorescent light emitting material or a phosphorescent light emitting material, respectively. Theoretically, the phosphorescence emission has an efficiency of about three times as much as that of fluorescent emission, but the material can be selected in consideration of the degree of color mixing with other light emission layers and the lifetime.

Such a solution process may be, for example, any one of inkjet printing, nozzle printing, transferring process, and thermal jet printing. This solution process can be done on a substrate without a separate mask or chamber.

Only the blue light emitting layer 144 of the above-described light emitting layer is formed by a vapor deposition method using a low molecular material. This is because when the blue light emitting layer 144 is formed by a solution process, sufficient efficiency can not be obtained compared with other light emitting layers, It falls. If a blue light emitting layer having improved efficiency and stability is developed by a solution process, the blue light emitting layer may also be formed by a solution process. In the organic light emitting device according to the illustrated first embodiment, the blue light emitting layer is formed of a low molecular material which is applied to a vacuum deposition method.

The optical enhancement layer 1462 located at the center of the second common layer 146 is basically composed of an electron transporting organic material 1460 constituting the first electron transporting layer 1461 and the second electron transporting layer 1463, Doped with n-type impurity which increases the mobility of electrons. This may be applicable to the case where the first and second electron transporting layers 1461 and 1463 are made of the same material or different materials. In the former case, the electron transporting material is continuously supplied in the same chamber, and the first electron transport layer 1461, the light extraction enhancement layer 1462, and the second electron transport layer 1463 are continuously formed, Lt; RTI ID = 0.0 > (1462). ≪ / RTI > In the latter case, the first electron transporting material is first supplied in the chamber to form the first electron transporting layer 1461, then the first electron transporting material and the second electron transporting material are supplied simultaneously, and the n-type impurity The light extraction enhancing layer 1462 is formed by co-deposition to form the second electron transporting layer 1463, and then only the second electron transporting material is supplied to form the second electron transporting layer 1463.

The n-type impurity may be an alkali metal, an alkaline earth metal or other n-type organic dopant. For example, it may be lithium (Li), calcium (Ca), cesium (Cs), or magnesium (Mg) and is doped to an electron transporting material of the light extracting enhancement layer 1462 by about 10% or less.

In addition, the n-type impurity may be an organic material or an inorganic material capable of increasing electron mobility of the first and second electron transporting layers 1461 and 1463.

Meanwhile, the blue light emitting layer 144, the first electron transport layer 1461, the light extraction enhancement layer 1462, and the second electron transport layer 1463 are formed between the first and second electrodes 132 and 138 Layer formed as a whole and formed by a vacuum deposition method. These layers are formed without a mask and without region separation.

The mobility of electrons is improved by the provision of the light extracting enhancement layer 1462 doped with the n-type impurity to improve the hole / electron recombination ratio in the light emitting layer. Even when the red light emitting layer and the green light emitting layer are selectively driven, It is easy to transfer electrons to the red light emitting layer or the green light emitting layer where light emission is to be performed, and the recombination rate is improved in the light emitting layer of the corresponding color, so that the color mixing of the light emitting color is hardly observed.

Further, even if the thickness of the second common layer 146 is increased as compared with that of the general hybrid type organic light emitting device due to the provision of the light extracting enhancement layer 1462 doped with the n-type impurity, The device efficiency is improved.

The first electron transport layer 1461 and the second electron transport layer 1463 are formed of the same material. The first and second electron transport layers 1461 and 1463 may have the same thickness or different thicknesses.

The first common layer 134 includes a hole transport layer (HTL) 1342. In some cases, the first common layer 134 may further include a hole injection layer 1341 under the hole transport layer 1342, as shown in FIG. The first common layer 134 may be formed as a single layer including a hole transporting material and a hole injecting material, or may be formed by dividing the first common layer 134 into a plurality of layers. In either case, the first common layer 134 is a layer that transmits holes from the first electrode 132 to the light emitting layer (EML).

In addition, the first electrode 132 and the second electrode 148 are defined by a transparent electrode on one side and a reflective electrode on the other side, and a light emission direction is defined. For example, the first electrode 132 is made of a transparent electrode such as ITO (Indium Tin Oxide), and the second electrode 148 is made of a reflective metal such as Al, The first electrode 143 includes a laminate including a reflective metal such as Ag / ITO, and a metal laminate is disposed on the second electrode 148 to have a thickness of 20 nm or less of Mg: Ag The top emission can be achieved.

Here, one of the first electrode 132 and the second electrode 148 may be patterned for each pixel, and the patterned electrode is connected to the thin film transistor included in the cell driving unit of the TFT substrate for voltage application .

Hereinafter, an example in which the organic light emitting diode according to the first embodiment of the present invention is applied to the active matrix system will be described.

FIG. 2 is a cross-sectional view illustrating an active matrix organic light emitting display device to which an organic light emitting diode according to a modification of the first embodiment is applied. The example shown in Fig. 2 shows only one pixel made up of a red pixel, a green pixel, and a blue pixel, and this shape is continuous in left and right and up and down.

As shown in FIG. 2, the active matrix type organic light emitting display includes a TFT substrate 100 including a driving thin film transistor, and an organic light emitting element connected to the driving thin film transistor.

The driving thin film transistor includes an active layer 114, a source electrode 108 and a drain electrode 110 connected to the source / drain regions 114s and 114d on both sides of the active layer 114, And a gate electrode 106 overlapped with the channel region 114c of the gate electrode 114c. Here, the source / drain regions 114s and 114d are doped with n-type impurities, respectively.

The TFT substrate 100 includes a buffer film 116, a driving thin film transistor formed on a predetermined portion of the buffer film 116, and an organic insulating film (not shown) 119).

Specifically, the TFT substrate 100 will be described as follows.

A front buffer layer 116 is formed on the substrate 101 and an active layer 114 is formed on a predetermined portion of the buffer layer 116.

The gate electrode 106 is formed to overlap with the channel region 114c of the active layer via the gate insulating film 112. The source electrode 108 and the drain electrode 110 are formed to be insulated with the gate electrode 106 and the interlayer insulating film 126 therebetween.

The source electrode 108 and the drain electrode 110 are electrically connected to the source region 114s and the drain region 114c of the active layer 114 into which the n + impurity is implanted through the interlayer insulating layer 126 and the contact holes passing through the gate insulating layer 112 And 114d, respectively.

The active layer 114 includes a lightly doped drain (LDD) region (not shown) in which an n-impurity is injected between the channel region 114c and the source and drain regions 114s and 114d to reduce an off current, There are also more.

The organic passivation layer 119 includes an inorganic passivation layer formed directly on the interlayer insulating layer 126 and the source and drain electrodes 108 and 110 and formed of an inorganic insulating material, Layer. ≪ / RTI >

The first electrode 132 is connected to each drain electrode 110 and is formed for each color pixel.

The organic light emitting device includes a first electrode 132 connected to the drain electrode 110 of the driving thin film transistor and a second electrode 132 connected to the first common layer 134, the red light emitting layer 136, the green light emitting layer 137, The second common layer 146, and the second electrode 148. The blue light emitting layer 144, the second common layer 146,

In some cases, banks may be further provided between the first common layers 134 so as to divide each color pixel, but the banks are omitted in the illustrated example. In this case, the bank when the bank is provided may be formed between the red light emitting layer 136 and the green light emitting layer 137, and also between the light emitting layers 136 and 137 and the blue sub pixel.

When a voltage is applied to the first electrode 132 and the second electrode 148 to form an electric field between the first and second electrodes 132 and 148, electrons are injected from the second electrode to recombine at the light emitting layers 136, 137 and 144 to generate exits. The excitons drop to the ground state and light is emitted to the bottom.

As shown in FIG. 2, a hybrid connecting layer (layer) is formed between the first layer of the red light emitting layer 136 and the green light emitting layer 137 and the second layer of the blue light emitting layer 144, (HCL) 142 may be further formed to control the charge balance between the red and green light emitting layers 136 and 137 and the blue light emitting layer 144. In this case, the hybrid connection layer 142 overlaps the red light emitting layer 136 or the green light emitting layer 137 with the blue light emitting layer in the red pixel and the green pixel, so that pure red light and green light are not emitted from the corresponding pixel, To prevent part from occurring and to improve color purity. For example, when the hybrid connection layer 142 performs only red light emission or green light emission, the hybrid connection layer 142 functions to prevent the hole / electron recombination in the blue light emission layer.

Hereinafter, another embodiment of the organic light emitting device of the present invention will be described.

3 is a cross-sectional view illustrating an organic light emitting diode according to a second embodiment of the present invention.

As shown in FIG. 3, the organic light emitting device according to the second embodiment of the present invention has different materials for the first electron transporting layer 261 and the second electron transporting layer 263. In this case, the light extraction enhancing layer 262 is formed by mixing the first electron transporting material and the second electron transporting material and injecting n-type impurity into the mixture.

Other configurations are the same as those of the above-described first embodiment, and the same reference numerals are not repeated.

The following is a comparison of the characteristics of the organic light emitting device of the present invention and the organic light emitting device of the comparative example.

4 is a cross-sectional view illustrating an organic light emitting device according to a comparative example.

As shown in FIG. 4, the organic light emitting device according to the comparative example includes a red light emitting layer 13 and a green light emitting layer (not shown) formed between the first electrode 10 and the second electrode 17, A blue light emitting layer 15 which overlaps with the red light emitting layer 13 and the green light emitting layer 14 and is formed over the red / green and blue pixels; A layer 11 and a hole transport layer 12 and an electron transport layer 16 formed between the blue light emitting layer 15 and the second electrode 17.

FIGS. 5A and 5B are graphs showing the intensities of light according to the driving voltages applied to the red light emitting layer portion and the green light emitting layer portion in the organic light emitting device of FIG.

As shown in FIG. 5A, the organic light emitting device according to the comparative example exhibits blue light emission peak characteristics even when pure red light is emitted, and some blue light emission peak characteristics are exhibited even when pure green light is emitted, as shown in FIG. 5B. In this case, if the driving voltage is increased, such blue light emission peak characteristics are further mitigated, but this causes the driving voltage to be increased when the red light or the green light is emitted.

As shown in Table 1, when the red light emission and the green light emission are respectively about 1000 nits illuminance, the luminance values for current are 7.6Cd / A and 23.6Cd / A, the driving voltages are 5.3V and 5.0V, respectively, Under these driving conditions, it can be expected that the blue emission peak characteristic appears.

The color coordinates CIEx and CIEy at the time of red emission are 0.613 and 0.374, respectively, and it is difficult to realize a pure red color.

In addition, the color coordinates CIEx and CIEy at the time of green light emission are 0.368 and 0.603, respectively, and it is difficult to realize pure green.

This means that the color purity is reduced in the red pixel and the green pixel, respectively. In the present invention, the color purity is improved without increasing the driving voltage.

6 is a cross-sectional view illustrating an organic light emitting device according to a modification of the first embodiment of the present invention.

6, the organic light emitting device according to the modification of the first embodiment of the present invention includes a red light emitting layer 136, a first layer of the green light emitting layer 137, and a blue light emitting layer 144 formed commonly over all the pixels. A hybrid connection layer 142 is further formed between the second layer of the first electron transport layer 1461 and the second electron transport layer 1463, and the electron transport layer is formed of a three-layer laminate of the first electron transport layer 1461, the light extraction enhancement layer 1462, , Which is different from the above-described comparative example.

That is, the hole injection layer 1342, the hole transport layer 1342 on the first electrode 132, and the second electrode 148 on the second electron transport layer 1463 are the same as those in the comparative example.

Here, the organic light emitting device according to the modified example of the first embodiment of the present invention is an experiment in which the materials of the first electron transport layer 1461 and the second electron transport layer 1463 are the same electron transport material, The enhancement layer 1462 is formed by doping an n-type impurity into the material of the first electron transport layer 1461.

FIGS. 7A and 7B are graphs showing the intensities of light according to wavelengths of driving voltage application of the red light emitting layer portion and the green light emitting layer portion in the organic light emitting device of FIG.

As shown in FIG. 7A, the organic light emitting device according to the modification of the first embodiment of the present invention exhibits red emission peak characteristics only when pure red emission is performed regardless of the driving voltage. As shown in FIG. 7B, It can be seen that only the green luminescence peak characteristic appears, and it can be understood that it has color purity.

As shown in Table 2, when the red light emission and the green light emission were respectively adjusted to about 1000 nits, the luminance values of the currents were 8.3 Cd / A and 27.1 Cd / A, respectively, The driving voltages are 5.7V and 5.5V, respectively, and there is a slight increase, but it can be confirmed that there is almost no driving voltage increase within 10%.

Particularly, it is confirmed that the color coordinates CIEx and CIEy at the time of emitting red light are 0.670 and 0.326, respectively, and it is possible to realize a pure red color, and the color coordinates CIEx and CIEy at the time of green light emission are 0.330 and 0.620, respectively, It can be confirmed that the efficiency and color purity are improved when the organic light emitting device is applied.

In the structure of FIG. 6, when the electron transport layer is formed as a single layer without the light extraction enhancement layer and only the hybrid connection layer is provided only between the second layer of the blue light emitting layer and the first layer of the red / green light emitting layer, The voltage was increased by 1.5 V or more from the red light emission and the green light emission, respectively, and the driving voltage tended to increase by about 30% as compared with the comparative example. This is caused by the fact that when only the hybrid connection layer is provided, the injection of holes and electrons into the light emitting layer is partially restricted and the performance is deteriorated.

That is, in the organic light emitting device of the present invention, it can be seen that the light extraction enhancement layer located at the center of the electron transport layer plays an important role in increasing the color purity and improving the efficiency. Also, it can be seen that when only the hybrid connection layer is provided, the contrast driving voltage is reduced and the efficiency is improved.

Hereinafter, a method of manufacturing an organic light emitting diode of the present invention will be briefly described with reference to FIG. 1 through a cross-sectional view.

A method of manufacturing an organic light emitting device of the present invention is performed in the following order.

First, the TFT substrate 100 in which the first to third color pixels (which will be described as red pixels, green pixels, and blue pixels in the following examples) is defined in advance is prepared. Here, a color filter of each color may be formed in each color pixel, or light emission of a corresponding color pixel may be defined by the provision of a light emitting layer of each color to be formed later without a color filter layer. In the former case, the light emitting layer for each color can be driven simultaneously.

Next, a first electrode 132 is formed on the TFT substrate 100 by sputtering or the like.

Then, a first common layer 134 is formed by coating a low molecular material or a polymer material having a hole injecting property and / or a hole transporting property on the first electrode 132 by a solution process. As shown in the figure, the hole injection layer 1341 and the hole transport layer 1342 may be formed separately or may be formed as a single layer on the first electrode 132.

Next, a red light emitting layer 136 is formed on the red pixel and a green light emitting layer 137 is formed on the green pixel through a solution process on the first common layer 134, respectively.

The blue light emitting layer 144 and the first electron transport layer 1461 are successively formed on the red, green and blue light emitting layers 136 and 137, respectively, through a deposition process, The light extraction enhancement layer 1462, and the second electron transport layer 1463 are formed.

Next, a second electrode 148 is formed on the second electron transporting layer by a method such as sputtering.

As described above, the method of manufacturing an organic light emitting diode of the present invention includes a hybrid type organic light emitting device in which a soluble process method and an evaporation method are combined, and an n-type doped light extraction By applying the enhancement layer, the color purity corresponding to the regions of the red light emitting layer and the green light emitting layer formed in the individual pixels can be improved and the light extraction efficiency can be improved.

The foregoing description is merely illustrative of the present invention, and various modifications may be made by those skilled in the art without departing from the spirit of the present invention. Accordingly, the embodiments disclosed in the specification of the present invention are not intended to limit the present invention. The scope of the present invention should be construed according to the following claims, and all the techniques within the scope of equivalents should be construed as being included in the scope of the present invention.

100: TFT substrate 101: substrate
132: first electrode 134: first common layer
136: red luminescent layer 137: green luminescent layer
142: hybrid connection layer EML: light emitting layer
144: blue light emitting layer 146: second common layer
148: Second electrode 1341: Hole injection layer
1342: hole transport layer 1461: first electron transport layer
1462: light extraction enhancement layer 1463: second electron transport layer

Claims (21)

A substrate divided into first to third color pixels;
A first electrode formed on the substrate; a second electrode facing and spaced apart from the first electrode;
A first color light emitting layer formed between the first electrode and the second electrode and including a first color light emitting layer formed on the first color pixel and a second color light emitting layer formed on the second color pixel, A light emitting layer formed of a second layer of a third color light emitting layer formed on the pixel;
A first electron transporting layer, a light extracting enhancement layer, and a second electron transporting layer sequentially stacked between the light emitting layer and the second electrode; And
And a common layer between the first electrode and the light emitting layer,
Wherein the first electron transporting layer and the second electron transporting layer are each made of an electron transporting organic material,
Wherein the light extracting enhancement layer comprises electron transporting organic materials that make up the first electron transporting layer and the second electron transporting layer and wherein the electron transporting organic materials are doped with n-type impurities of 10% or less .
delete The method according to claim 1,
Wherein the n-type impurity is an alkali metal. The method according to claim 1,
Wherein the n-type impurity is a substance that increases the electron mobility of the first and second electron transporting layers. The method according to claim 1,
Wherein the first electron transporting layer and the second electron transporting layer are made of the same electron transporting organic material. The method according to claim 1,
Wherein the first electron transporting layer and the second electron transporting layer are made of different electron transporting organic materials. The method according to claim 1,
Wherein the second layer, the first electron transporting layer, the light extracting enhancement layer, and the second electron transporting layer of the light emitting layer are formed as a whole between the first and second electrodes without any region separation. The method according to claim 1,
Wherein the light emitting layer further comprises a hybrid connection layer between the first layer and the second layer. The method according to claim 1,
Wherein the common layer comprises a hole transporting layer. 10. The method of claim 9,
Wherein the common layer further comprises a hole injection layer. The method according to claim 1,
Wherein the third color light emitting layer is a blue light emitting layer, and the first color light emitting layer and the second color light emitting layer are mixed with the third color light emitting layer to emit white light. The method according to claim 1,
Wherein the first layer of the common layer and the light emitting layer is made of a solution material. 13. The method of claim 12,
Wherein the third color light emitting layer, the first electron transporting layer, the light extracting improving layer, and the second electron transporting layer are made of a low molecular material. The method according to claim 1,
Wherein the substrate includes a thin film transistor array connected to the first electrode. A red pixel, a green pixel, and a blue pixel;
A first electrode formed on the substrate; a second electrode facing and spaced apart from the first electrode;
A red light emitting layer formed between the first electrode and the second electrode and formed on the red pixel; a green light emitting layer formed on the green pixel;
A blue light emitting layer overlapping the red light emitting layer and the green light emitting layer and formed in common to the red, green, and blue pixels;
A layer of the red light emitting layer and the green light emitting layer disposed on the same layer, and a hybrid connection layer provided between the layers of the blue light emitting layer;
A first electron transporting layer, a light extracting enhancement layer, and a second electron transporting layer, which are sequentially stacked, between the blue light emitting layer and the second electrode; And
And a common layer between the first electrode and the red light emitting layer and the green light emitting layer located on the same layer,
Wherein the first electron transporting layer and the second electron transporting layer are each made of an electron transporting organic material,
Wherein the light extracting enhancement layer comprises electron transporting organic materials that make up the first electron transporting layer and the second electron transporting layer and wherein the electron transporting organic materials are doped with n-type impurities of 10% or less .
delete 16. The method of claim 15,
The common layer, the red luminescent layer and the green luminescent layer are made of a solution material,
Wherein the blue light emitting layer, the first electron transporting layer, the light extracting enhancement layer, and the second electron transporting layer are made of a low molecular material. Preparing a substrate on which a first color pixel to a third color pixel are divided and defined;
Forming a first electrode on the substrate;
Forming a common layer on the first electrode by a solution process;
Forming a first color light emitting layer on the first color pixel and a second color light emitting layer on the second color pixel, respectively, on the common layer through a solution process;
Forming a third color light emitting layer covering the first color light emitting layer and the second color light emitting layer over the first color pixel to the third color pixel through a deposition process;
Forming a first electron transporting layer on the third color light emitting layer as a first electron transporting organic material through a deposition process;
Doping an n-type impurity in the electron transporting material on the first electron transporting layer to deposit a light extraction enhancing layer;
Depositing a second electron transporting layer on the light extraction enhancing layer with a second electron transporting organic material; And
And forming a second electrode on the second electron transporting layer,
Wherein the electron transporting material of the light extracting enhancement layer comprises the first electron transporting organic material and the second electron transporting organic material,
Wherein the light extraction enhancement layer contains the n-type impurity in an amount of 10% or less.
delete 19. The method of claim 18,
The solution process for forming the common layer, the first color light-emitting layer, and the second color light-
Characterized in that the method comprises any one of inkjet printing, nozzle printing, transferring method, slit coating, gravia printing, and thermal jet printing. 19. The method of claim 18,
And forming a hybrid connection layer between the first color light emitting layer and the second color light emitting layer and between the layer of the third color light emitting layer and the organic light emitting layer.

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