KR102016564B1 - Organic light emitting diode device and method for manufacturing of the same - Google Patents

Abstract

An organic light emitting display device according to an embodiment of the present invention is a substrate, a first electrode located on the substrate, a light emitting layer located on the first electrode, a buffer layer on the light emitting layer, a non-polar organic compound, And a second electrode on the buffer layer.

Description

Organic light emitting device and its manufacturing method {ORGANIC LIGHT EMITTING DIODE DEVICE AND METHOD FOR MANUFACTURING OF THE SAME}

The present invention relates to an organic light emitting device, and to an organic light emitting device capable of preventing damage to the light emitting layer by a photo process, and a manufacturing method thereof.

Recently, the importance of flat panel displays (FPDs) has increased with the development of multimedia. In response to this, a variety of liquid crystal displays (LCDs), plasma display panels (PDPs), field emission displays (FEDs), organic light emitting devices (Organic Light Emitting Devices), etc. Flat panel displays have been put into practical use.

In particular, the organic light emitting display device has a high response time with a response speed of 1 ms or less, low power consumption, and self-luminous light. In addition, there is no problem in viewing angle, which is advantageous as a moving image display medium regardless of the size of the device. In addition, low-temperature manufacturing is possible, and the manufacturing process is simple based on the existing semiconductor process technology has attracted attention as a next-generation flat panel display device in the future.

The organic light emitting device includes a light emitting layer between the anode electrode and the cathode electrode, so that holes supplied from the anode electrode and electrons received from the cathode electrode combine in the light emitting layer to form an exciton, a hole-electron pair, and then the exciton is bottomed. The light emitted by the energy generated when returning to the state.

The light emitting layer described above is formed by a vacuum evaporation method formed by evaporating a light emitting material to a substrate in a vacuum chamber. A metal mask, such as a fine metal mask (FMM), is disposed on the substrate in the vacuum chamber to partition the emission layer for each of a plurality of pixels. However, metal masks are applicable to high resolution but are difficult to large area. Therefore, techniques for patterning the light emitting layer using the photolithography method have been developed. However, organic layers of organic light emitting diodes, such as a light emitting layer, are made of organic materials, and thus are easily damaged by chemical solutions during a photolithography process, thereby deteriorating device characteristics.

The present invention provides an organic electroluminescent device and a method of manufacturing the same, which can prevent the damage of the light emitting layer during the photo process by forming a buffer layer on the light emitting layer.

In order to achieve the above object, an organic light emitting display device according to an embodiment of the present invention is located on a substrate, a first electrode located on the substrate, a light emitting layer located on the first electrode, the light emitting layer, And a second electrode positioned on the buffer layer, the buffer layer made of a nonpolar organic compound.

The nonpolar organic compound is characterized in that non-fluorine (Non-Fluorine).

The non-polar organic compound is characterized in that it is made of any one selected from the group consisting of TCTA, CBP, NPB, UGH2, SiCa, 4CZPBP and CzSi.

The buffer layer is characterized by consisting of a thickness of 10 to 100 내지.

The nonpolar organic compound is characterized in that it serves as at least one host of the light emitting layer.

At least one of a hole injection layer or a hole transport layer between the first electrode and the light emitting layer, characterized in that it comprises at least one of an electron transport layer or an electron injection layer between the buffer layer and the second electrode.

In addition, the method of manufacturing an organic light emitting display device according to an embodiment of the present invention comprises the steps of forming a first electrode on a substrate, forming a PR pattern on the first electrode, on the substrate on which the PR pattern is formed Depositing a light emitting material layer by co-depositing a first host, a second host, and a dopant of a non-polar organic compound, and depositing only the first host on the light emitting material layer to form a buffer material layer; Stripping with a fluorine-based strip liquid to form a light emitting layer and a buffer layer, and forming a second electrode on the buffer layer, wherein the second host is made of a nonpolar organic compound.

The forming of the light emitting material layer and the buffer material layer may include mounting a substrate on which the PR pattern is formed in a deposition chamber and preparing the first host, the second host, and the dopant deposition source, and the first host. Depositing the second host and the dopant deposition source on the substrate to form a light emitting material layer, and blocking the second host and the dopant deposition sources and depositing only the first host to form a buffer material layer. Characterized in that it comprises a.

The PR pattern is formed by fluorine-based PR.

The organic electroluminescent device according to an embodiment of the present invention has an advantage that the light emitting layer can be patterned by photolithography by using an organic compound that is not damaged by the stripping liquid as a host or buffer layer of the light emitting layer. In addition, since the light emitting layer is not damaged by the stripping liquid, there is an advantage that the characteristics of the organic light emitting display device can be prevented from being lowered.

1 is a view showing an organic light emitting display device according to an embodiment of the present invention.
2A to 2F are diagrams illustrating processes for manufacturing an organic light emitting display device according to one embodiment of the present invention.
Figure 3a is an image showing the surface of the substrate according to Comparative Example 1, Figure 3b is an image showing the surface of the substrate according to Example 1.
4A is an image showing the surface of the light emitting layer according to Comparative Example 3 by AFM, and FIG. 4B is an image showing the surface of the light emitting layer according to Example 3 by AFM.

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

1 is a view showing an organic light emitting display device according to an embodiment of the present invention.

Referring to FIG. 1, an organic light emitting display device 100 according to an exemplary embodiment of the present invention may include a substrate 110, a first electrode 120, a hole injection layer 130, a hole transport layer 140, and a light emitting layer 150. ), A buffer layer 160, an electron transport layer 170, an electron injection layer 180, and a second electrode 190.

The substrate 110 may be made of glass, plastic, or metal, and may further include a semiconductor layer, a gate electrode, a source electrode, and a drain electrode.

The first electrode 120 is an anode that injects holes, and may be a transparent electrode or a reflective electrode. When the first electrode 120 is a transparent electrode, the first electrode 120 may be formed of any one of indium tin oxide (ITO), indium zinc oxide (IZO), or zinc oxide (ZnO). In addition, when the first electrode 120 is a reflective electrode, the first electrode 120 is formed of any one of aluminum (Al), silver (Ag), or nickel (Ni) under a layer made of any one of ITO, IZO, or ZnO. The reflective layer may further include a reflective layer, and in addition, the reflective layer may be included between two layers made of any one of ITO, IZO, or ZnO.

The first electrode 120 may be formed using a sputtering method, an evaporation method, a vapor phase deposition method, or an electron beam deposition method.

The hole injection layer 130 may play a role of smoothly injecting holes from the first electrode 120 to the light emitting layer 150, and may include cupper phthalocyanine (CuPc) and poly (3,4) -ethylenedioxythiophene (PEDOT). , PANI (polyaniline) and NPD (N, N-dinaphthyl-N, N'-diphenyl benzidine) may be made of any one or more selected from the group consisting of, but is not limited thereto. The hole injection layer 130 may be formed using an evaporation method or a spin coating method, and the thickness of the hole injection layer 130 may be 1 to 150 nm.

The hole transport layer 140 serves to facilitate the transport of holes, NPD (N, N-dinaphthyl-N, N'-diphenyl benzidine), TPD (N, N'-bis- (3-methylphenyl)- N, N'-bis- (phenyl) -benzidine), s-TAD and MTDATA (4,4 ', 4 "-Tris (N-3-methylphenyl-N-phenyl-amino) -triphenylamine) The hole transport layer 140 may be formed using an evaporation method or a spin coating method, and the thickness of the hole transport layer 140 may be 5 to 150 nm.

The emission layer 150 may be formed of a material emitting red, green, and blue, and may be formed using phosphorescent or fluorescent materials.

For example, when the light emitting layer 150 is red, it includes a host including CBP (carbazole biphenyl) or mCP (1,3-bis (carbazol-9-yl), and PIQIr (acac) (bis (1- a dopant comprising any one or more selected from the group consisting of phenylisoquinoline) acetylacetonate iridium, PQIr (acac) (bis (1-phenylquinoline) acetylacetonate iridium), PQIr (tris (1-phenylquinoline) iridium) and PtOEP (octaethylporphyrin platinum) It may be made of a phosphor containing, alternatively may be made of a fluorescent material including PBD: Eu (DBM) ₃ (Phen) or Perylene, but is not limited thereto.

When the light emitting layer 150 is green, it may include a host including CBP or mCP, and may be made of a phosphor including a dopant including Ir (ppy) 3 (fac tris (2-phenylpyridine) iridium). Alternatively, it may be made of a fluorescent material including Alq3 (tris (8-hydroxyquinolino) aluminum), but is not limited thereto.

When the light emitting layer 150 is blue, it may be made of a phosphor including a host including CBP or mCP and including a dopant including (4,6-F ₂ ppy) ₂ Irpic. It may be made of a fluorescent material including any one selected from the group consisting of DPVBi, spiro-6P, distilbenzene (DSB), distriarylene (DSA), PFO-based polymer and PPV-based polymer, but is not limited thereto.

In particular, in the present embodiment, the light emitting layer 150 is composed of two hosts and one dopant material. The first host of the two host materials is made of a non polar organic compound. Among the nonpolar organic compounds, non-fluorine organic compounds containing no fluorine (F) are preferable. Non-fluorinated organic compounds exhibiting such a polarity include, for example, tris (4-carbazoyl-9-ylphenyl) amine (TCTA), CBP (4,4'-bis (N-carbazolyl) -1,1'- biphenyl), NPB (N, N'-bis (1-naphthyl) -N, N'-diphenyl-1,1'-biphenyl-4,4'-diamine), UGH2 (1,4-phenylene bis (triphenylsilane) , SiCa (diphenyldi (4- (9-carbazolyl) phenyl) silane), 4CZPBP (2,2'-bis (4-carbazolylphenyl) -1,1'-biphenyl) and CzSi (9- (4-tert-butylphenyl) -3,6-bis (triphenylsilyl) -9H-carbazole), and the second of the two host materials is a material that does not overlap with the material used as the first host described above. Any organic compound usable as a host may be used, and the dopant may be any known dopant in addition to the above-described materials.

On the other hand, the buffer layer 160 is to prevent the light emitting layer 150 from being damaged by the stripping liquid during the process described later, and is made of a non-polar organic compound. Among the nonpolar organic compounds, non-fluorine organic compounds containing no fluorine (F) are particularly preferable. That is, the buffer layer 160 is made of the same material as the first host of the light emitting layer 150 described above.

The buffer layer 160 has a thickness of about 10 to about 100 microns. Here, when the thickness of the buffer layer 160 is 10 GPa or more, there is an advantage that the light emitting layer can be protected from the stripping liquid during the patterning process of the light emitting layer. When the thickness of the buffer layer 160 is 100 GPa or less, the thickness of the device becomes thick and the luminous efficiency is lowered. There is an advantage that can be prevented.

On the other hand, in another embodiment of the present invention, the light emitting layer 150 may be made of one host and one dopant. In this case, one host includes the first host described above. Therefore, by using a material having the same characteristics as the above-described buffer layer as a host of the light emitting layer, the light emitting layer itself has a property that is not damaged by the stripping liquid. In this case, the buffer layer 160 may be omitted. That is, the light emitting layer of the present invention may have a buffer layer when it is composed of two hosts and one dopant, and may not have a buffer layer when it is composed of one host and one dopant.

However, in the present invention, the light emitting layer formed of two hosts and one dopant or the light emitting layer formed of one host and one dopant may be selected in consideration of characteristics such as luminous efficiency of the light emitting layer and is not particularly limited.

On the other hand, the electron transport layer 170 serves to facilitate the transport of electrons, at least one selected from the group consisting of Alq3 (tris (8-hydroxyquinolino) aluminum), PBD, TAZ, spiro-PBD, BAlq and SAlq It may be made of but is not limited thereto. The electron transport layer 170 may be formed using an evaporation method or a spin coating method, and the thickness of the electron transport layer 170 may be 1 to 50 nm. In addition, the electron transport layer 170 may also prevent the holes injected from the first electrode 120 from passing through the emission layer 150 to the second electrode 190. In other words, it serves as a hole blocking layer to effectively bond holes and electrons in the emission layer 150.

The electron injection layer 180 serves to facilitate the injection of electrons, may be made of any one selected from the group consisting of MgF ₂ , LiF, NaF, KF, RbF, CsF, FrF and CaF ₂ . The electron injection layer 180 may be formed to a thickness of 10 to 30 Å.

The second electrode 190 may be made of magnesium (Mg), calcium (Ca), aluminum (Al), silver (Ag), or an alloy thereof having a low work function. Here, the second electrode 190 may be formed to a thickness thin enough to transmit light when the organic light emitting diode is a front or double-side light emitting structure, and when the organic light emitting diode is the bottom light emitting structure, It can be formed thick enough to reflect.

As described above, the organic electroluminescent device according to the exemplary embodiment of the present invention has an advantage that the light emitting layer can be patterned by photolithography by using an organic compound that is not damaged by the stripping liquid as a host or buffer layer of the light emitting layer. In addition, since the light emitting layer is not damaged by the stripping liquid, there is an advantage that the characteristics of the organic light emitting display device can be prevented from being lowered.

Hereinafter, a manufacturing method according to the structure of the organic light emitting device described above will be described in detail with reference to the following drawings.

2A to 2F are diagrams illustrating processes for manufacturing an organic light emitting display device according to one embodiment of the present invention. In FIGS. 2A to 2F, a method of manufacturing a plurality of light emitting layers is illustrated differently from FIG. 1, but FIG. 1 is a view showing only one patterned light emitting layer to explain each configuration of an organic light emitting diode. do. In addition, in the following description to be repeated with respect to the description related to FIG. 1 will be omitted, and the same reference numerals for the same configuration to help the convenience of understanding.

Referring to FIG. 2A, the first electrode 120 is formed on the substrate 110. The substrate 110 is divided into a plurality of pixels in which at least one thin film transistor is formed, and the first electrode 120 is formed in each of the plurality of pixels. The hole injection layer 120 and the hole transport layer 130 are sequentially deposited on the first electrode 120. A photoresist (PR) layer 142 is formed on the hole transport layer 130. The PR layer 142 uses fluorine based PR which minimizes the reactivity with the organic material. More specifically, the fluorine-based PR uses a substance represented by the following formula as FDMA-MAMA.

After aligning the mask M partially opened on the PR layer 142, ultraviolet rays are exposed to UV light.

Next, referring to FIG. 2B, the exposed PR layer 142 is developed using a developer to form a plurality of PR patterns 143. At this time, the PR layer 142 in the region where ultraviolet rays are exposed is not developed by the developer, but the PR layer 142 in the region masked by the mask M is developed and removed by the developer. The developer is a fluorine-based developer, for example, using HFE (hydrofluoroether) represented by the following formula.

Next, referring to FIG. 2C, a substrate 110 in which the above-described PR pattern 143 is formed is mounted in the vacuum chamber VC, and a first host evaporation source S1 containing a first host and a second host are included. 2 Prepare a dopant evaporation source S3 containing a host evaporation source S2 and a dopant. Subsequently, deposition of the first host, the second host, and the dopant evaporation sources S1, S2, and S3 is started in a vacuum atmosphere to form a light emitting material layer on the substrate 110. At this time, the amount of the dopant is adjusted through the shutter of the dopant evaporation source (S3). Subsequently, when a light emitting material layer having a desired thickness is formed, deposition is stopped by closing shutters of the second host and dopant evaporation sources S2 and S3, and deposition of the first host evaporation source S1 is continued on the light emitting material layer. A buffer material layer is formed.

Accordingly, as illustrated in FIG. 2D, the light emitting material layer 152 and the buffer material layer 162 are formed on the substrate 110. In this case, the light emitting material layer 152 and the buffer material layer 162 are formed on the surface of the plurality of PR patterns 143 and the hole transport layer 140 between the PR patterns 143. Accordingly, the light emitting material layer 152 and the buffer material layer 162 are divided by the PR patterns 143.

Next, the PR patterns 143 are stripped on the substrate 110 using stripping liquid. That is, as the PR patterns 143 are stripped by the stripping liquid, the light emitting material layer 152 and the buffer material layer 162 formed on the PR pattern 143 are simultaneously removed. The stripping solution uses a stripping solution containing 5% of HMDS (hexamethyldisilazane) in the above-described HFE. In this case, the stripping liquid uses a fluorine-based stripping liquid, and the buffer material layer made of a nonpolar organic compound does not react with the stripping liquid to prevent the lower light emitting material layer from being damaged by the stripping liquid. Thus, as shown in FIG. 2E, the patterned light emitting layer 150 and the buffer layer 160 are formed on the hole transport layer 140.

Next, referring to FIG. 2F, the electron transport layer 170, the electron injection layer 180, and the second electrode 190 are sequentially stacked on the substrate 110 on which the buffer layer 160 is formed. To manufacture an organic light emitting device according to.

As described above, in the method of manufacturing an organic light emitting display device according to an embodiment of the present invention, by using a fluorine-based PR and a fluorine-based strip liquid, by forming a buffer material layer that does not react with the fluorine-based strip liquid on the light emitting layer, There is an advantage of preventing the light emitting layer from being damaged by the stripping liquid.

Hereinafter, the organic light emitting display device of the present invention will be described in detail in the following Examples. However, the following examples are merely to illustrate the present invention is not limited to the following examples.

Example  One

The light emitting area was patterned to a size of 3 mm x 3 mm on the glass substrate and then washed. ITO, an anode electrode, was formed to a thickness of 500 kPa on the substrate, CuPc, a hole injection layer, was formed to a thickness of 1000 kPa, and PDMA-MAMA, a fluorine-based PR, was coated.

Comparative example  One

Non-fluorine based PR was coated with PR under the same conditions as in Example 1 above.

The surfaces of the substrates prepared according to Example 1 and Comparative Example 1 described above were observed. 3A is an image showing the surface of a substrate according to Comparative Example 1, and FIG. 3B is an image showing the surface of the substrate according to Example 1. FIG.

Referring to FIG. 3A, when the non-fluorine-based PR is coated on the hole injection layer, the organic material of the hole injection layer reacts with PR to generate cracks and bubbles on the PR surface. On the other hand, referring to Figure 3b, when the fluorine-based PR coating the hole injection layer and PR did not react to show a clean surface.

Example  2

The light emitting area was patterned to a size of 3 mm x 3 mm on the glass substrate and then washed. ITO, which is an anode electrode, was formed on the substrate at a thickness of 500 kPa, CuPc, which was a hole injection layer, was formed at a thickness of 1000 kPa, and TPD, which was a hole transport layer, was formed at a thickness of 1000 kPa. Then, using a FFM mask, the first host TCTA, the second host TPBI (benzimidazole derivative), and the dopant (4,6-F ₂ ppy) ₂ Irpic (doping concentration of 15%) were deposited to a thickness of 340 Å. The light emitting layer was formed, and only the TCTA as the first host was further deposited to a thickness of 50 GPa to form a buffer layer. Next, spiro-PBD, which is an electron transport layer, was formed to a thickness of 356 GPa, LiF was formed to an electron injection layer having a thickness of 5 GPa, and Al, a cathode electrode, was formed to a thickness of 800 GPa to fabricate an organic light emitting device.

Example  3

Under the same conditions as in Example 2, a PR pattern was formed on the hole transport layer by photolithography, and the first host TCTA, the second host TPBI (benzimidazole derivative), and the dopant (4,6- F ₂ ppy) ₂ Irpic (doping concentration of 15% of dopant) was deposited to a thickness of 340 을 to form a light emitting material layer, and only the first host TCTA was further deposited to a thickness of 50 을 to form a buffer material layer. The organic light emitting device was manufactured by varying only that the light emitting layer and the buffer layer were formed by stripping.

Comparative example  2

Under the same conditions as in Example 2, the organic light emitting diode was manufactured by forming the light emitting layer not including the first host and only not forming the buffer layer.

Comparative example  3

Under the same conditions as those of Comparative Example 2 described above, the organic light emitting diode was manufactured by using only the light emitting layer using the PR pattern as in Example 3 without using the FMM mask.

The driving voltage, luminous efficiency and power efficiency of the organic light emitting diodes manufactured according to Examples 2 and 3, Comparative Examples 2 and 3 were measured and shown in Table 1 below, and the surfaces of the light emitting layers of Comparative Examples 3 and 3 were measured. Was measured by AFM and the images are shown in FIGS. 4A and 4B.

Light emitting layer pattern method Driving voltage (V) efficiency Luminous Efficiency (cd / A) Power efficiency (lm / W) Comparative Example 2 Mask 3.9 35.5 28.6 100% Comparative Example 3 Photolithography 5.0 30.6 19.3 67% Example 2 Mask 4.3 33.3 24.0 100% Example 3 Photolithography 4.3 32.6 23.7 99%

First, referring to FIGS. 4A and 4B, in Comparative Example 3 in which the buffer layer is not formed, the light emitting layer is damaged by the stripping liquid, and thus the surface of the light emitting layer may be unevenly formed. On the other hand, in Example 3 in which the buffer layer is formed, it is understood that the surface of the light emitting layer is smooth because damage of the light emitting layer is not generated by the stripping liquid.

In addition, referring to Table 1, in the case of Comparative Examples 2 and 3, the power efficiency when the light emitting layer was patterned with the FMM mask was 100%. However, in Examples 2 and 3, when the light emitting layer was patterned by the FMM mask at 100%, the light emitting layer was patterned by the photolithography method to show 99%, indicating the same level of efficiency.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical configuration of the present invention described above may be modified in other specific forms by those skilled in the art to which the present invention pertains without changing its technical spirit or essential features. It will be appreciated that it may be practiced. Therefore, the embodiments described above are to be understood as illustrative and not restrictive in all aspects. In addition, the scope of the present invention is shown by the claims below, rather than the above detailed description. Also, it is to be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts are included in the scope of the present invention.

100 organic light emitting device 110 substrate
120: first electrode 130: hole injection layer
140: hole transport layer 150: light emitting layer
160: buffer layer 170: electron transport layer
180: electron injection layer 190: second electrode

Claims (13)

Board;
A first electrode on the substrate;
A light emitting layer on the first electrode;
A buffer layer on the light emitting layer, the buffer layer comprising a nonpolar organic compound; And
A second electrode on the buffer layer;
The non-polar organic compound is non-fluorine, and an organic light emitting diode, characterized in that any one selected from the group consisting of TCTA, NPB, UGH2, SiCa, 4CZPBP and CzSi.
delete delete According to claim 1,
The buffer layer is an organic light emitting device, characterized in that consisting of a thickness of 10 to 100Å.
According to claim 1,
The non-polar organic compound is an organic light emitting device, characterized in that acts as at least one host of the light emitting layer.
According to claim 1,
At least one of a hole injection layer or a hole transport layer between the first electrode and the light emitting layer,
An organic light emitting display device comprising at least one of an electron transport layer and an electron injection layer between the buffer layer and the second electrode.
Forming a first electrode on the substrate;
Forming a PR pattern on the first electrode;
A light emitting material layer is formed by co-depositing a first host, a second host, and a dopant of a nonpolar organic compound on the substrate on which the PR pattern is formed, and depositing only the first host on the light emitting material layer to form a buffer material layer. Forming;
Stripping the PR pattern with a fluorine strip liquid to form a light emitting layer and a buffer layer;
Forming a second electrode on the buffer layer; manufacturing method of an organic light emitting device comprising a.
The method of claim 7, wherein
Forming the light emitting material layer and the buffer material layer,
Mounting a substrate on which the PR pattern is formed in a deposition chamber and preparing the first host, the second host, and the dopant deposition source;
Depositing the first host, the second host, and the dopant deposition source on the substrate to form a light emitting material layer; And
Blocking the second host and the dopant deposition sources and depositing only the first host to form a buffer material layer.
The method of claim 8,
The PR pattern is a manufacturing method of an organic light emitting device, characterized in that formed with fluorine-based PR. According to claim 1,
And the buffer layer is made of the same material as the host of the light emitting layer.
According to claim 1,
The light emitting layer is an organic light emitting device comprising a first host, a second host and a dopant.
The method of claim 11, wherein
The buffer layer is an organic light emitting device, characterized in that made of the same material as the first host.
The method of claim 11, wherein
And the first host and the second host have different materials from each other.

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