KR20120075272A - Organic light emitting device of manufacturing method and display device of manufacturing method - Google Patents

Abstract

PURPOSE: A method for manufacturing an organic light-emitting device and a method for manufacturing a display device using the organic light-emitting device are provided to prevent the damage of an organic layer when forming an electrode with a sputtering method. CONSTITUTION: A reflective film(110) and a first electrode(112) are formed on a substrate(100). An organic layer is formed on the substrate in which the first electrode is formed. The organic layer comprises a hole injection layer(114), a hole-transport layer(116), a light-emitting layer(122), and a buffer layer(120). The buffer layer is composed of a material layer of a lanthanide system. A second electrode(128) is formed on the substrate in which the organic layer is formed.

Description

A manufacturing method of an organic light emitting element and a manufacturing method of a display device using the organic light emitting element {ORGANIC LIGHT EMITTING DEVICE OF MANUFACTURING METHOD AND DISPLAY DEVICE OF MANUFACTURING METHOD}

The present invention relates to an organic light emitting device, and more particularly, to a method of manufacturing an organic light emitting device and a method of manufacturing a display device, which can prevent damage to an organic layer when forming an electrode by a sputtering method.

In the organic light emitting device, an organic thin film layer is formed between an anode and a cathode. Holes are injected at the anode and electrons are injected at the cathode. The injected holes and electrons are combined in the organic thin film layer, which is an emission layer, to generate excitons, and the generated excitons are diffused to generate light. The generated light is emitted in the direction of the anode and the substrate to display luminance. On the other hand, in the organic EL device, the brightness is adjusted according to the amount of current injected into the cathode and the anode.

The organic light emitting diode is formed on the substrate in the order of an anode, an organic layer, and a cathode. As described above, since the cathode is formed on the substrate on which the organic layer is formed through the sputtering method, damage to the organic layer is seriously generated. At this time, the organic layer is damaged by sputtering ions.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a method of manufacturing an organic light emitting device and a method of manufacturing a display device, which can prevent damage to an organic layer when forming an electrode by a sputtering method.

To this end, the method of manufacturing an organic light emitting device according to the present invention comprises the steps of forming a reflective film and a first electrode on the substrate, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer on the substrate on which the reflective film and the first electrode is formed And forming an organic layer including a buffer layer, and forming a second electrode on the substrate on which the organic layer is formed, wherein the buffer layer is formed of a lanthanide-based material layer or an electron transport layer and a lanthanide-based material. The layer is formed by co-deposition.

The lanthanide series may include ytterbium (Yb), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), and gadolinium ( Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), and thulium (Tm).

The buffer layer may be formed of ytterbium (Yb) in the lanthanide series.

When the electron transport layer and the lanthanide-based material layer are bonded to each other to form a buffer layer, the lanthanide-based material layer is doped at 1 to 50% based on the thickness of the buffer layer.

In addition, the buffer layer is characterized in that formed to a thickness of 30 ~ 400Å.

A method of manufacturing a display device using an organic light emitting diode according to an exemplary embodiment of the present invention includes forming a thin film transistor on a substrate, forming a reflective film and a first electrode to be connected to a drain electrode of the thin film transistor, Forming an organic layer including a hole injection layer, a hole transporting layer, a light emitting layer, an electron transporting layer, and a buffer layer on the first electrode, and forming a second electrode on the substrate on which the organic layer is formed, wherein the buffer layer is lanthanum. It is formed by forming a group-based material layer or by co-depositing the electron transport layer and the lanthanide-based material layer.

The lanthanide series may include ytterbium (Yb), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), and gadolinium ( Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), and thulium (Tm).

The buffer layer may be formed of iridium in the lanthanide series.

When the electron transport layer and the lanthanide-based material layer are bonded to each other to form a buffer layer, the lanthanide-based material layer is doped at 1 to 50% based on the thickness of the buffer layer.

In addition, the buffer layer is characterized in that formed to a thickness of 30 ~ 400Å.

The organic light emitting device according to the present invention has a structure in which a reflective film, a first electrode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, a buffer layer, and a second electrode are stacked. In this case, the buffer layer according to the present invention is formed between the electron transport layer and the second electrode, and formed of a lanthanide-based material layer, or formed by co-depositing the electron transport layer and the lanthanide-based material layer.

The buffer layer serves as an electron injection layer and protects the organic layer during the sputtering process. That is, even if the second electrode is formed by sputtering on the substrate on which the organic layer is formed, damage can be prevented by the buffer layer.

1A to 1C are perspective views illustrating an organic light emitting diode according to an exemplary embodiment of the present invention.
2A to 2E are cross-sectional views illustrating a method of manufacturing an organic light emitting diode according to the present invention.
3 is an equivalent circuit diagram of an R, G, and B pixel of a display device using an organic light emitting diode according to an exemplary embodiment of the present invention.
4 is a cross-sectional view of a display device using the organic light emitting diode illustrated in FIG. 3.
5A through 5D are cross-sectional views illustrating a method of manufacturing a display device according to an exemplary embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The configuration of the present invention and the operation and effect thereof will be clearly understood through the following detailed description. Before describing the present invention in detail, the same components are denoted by the same reference symbols as possible even if they are displayed on different drawings. In the case where it is judged that the gist of the present invention may be blurred to a known configuration, do.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 1A to 5D.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 1A to 5D.

1 is a perspective view illustrating a white organic light emitting diode according to an exemplary embodiment of the present invention.

Referring to FIG. 1, an organic light emitting diode according to an exemplary embodiment includes a reflective layer 110, an organic layer including a first electrode 112, and an emission layer 122, and a second electrode 128. In the organic light emitting diode, when a voltage is applied between the first electrode 112 and the second electrode 128, holes are injected from the first electrode 112 and electrons are injected from the second electrode 128. Then, the light emitting layer 120 is recombined, and thus excitons are generated. As the excitons fall to the ground state, light is emitted to the front surface TOP.

The first electrode 112 is a transparent conductive material such as transparent conductive oxide (TCO) as an anode and is formed of indium tin oxide (ITO), indium zinc oxide (IZO), or the like. The reflective film 110 is formed of a reflective material such as aluminum under the first electrode 112.

The second electrode 128 is a conductive film that is transparent to the cathode and is formed of an alloy such as MgAg, MgIn, AlLi, or the like.

The organic layer includes a hole injection layer (HIL) 114, a hole transport layer (HTL) 116, a light emitting layer 122, an electron transport layer (ETL) 118, and a buffer layer 120. ) Are sequentially stacked and formed.

The hole injection layer 114 is a layer that receives holes from the first electrode 112, and the hole transport layer 114 is a layer that transports holes to the light emitting layer 122. In addition, the buffer layer 120 serves to inject electrons from the second electrode 128 and to protect organic layers during the deposition process, and the electron transport layer 118 is a layer for transporting electrons to the light emitting layer 122. As such, the hole injection layer 114, the hole transport layer 116, the buffer layer 120, and the electron transport layer 118 serve to transport and inject electrons and holes to facilitate recombination of electrons and holes.

The buffer layer 120 is formed of a lanthanide-based material layer or is formed by co-deposition of an electron transport layer and a lanthanide-based material layer. The buffer layer 120 serves as an electron injection layer and protects the organic layer during the deposition process.

Lanthanide-based elements include ytterbium (Yb), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), and gadolinium (Gd). ), Terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), and the like, and preferably formed of ytterbium (Yb).

When formed covalently with the material of the lanthanide-based material layer and the electron transport layer, the lanthanide-based material layer is doped at 1 to 50% based on the thickness of the buffer layer. The buffer layer 120 may be formed to have a thickness of 30 μs to 400 μs. As described above, the lanthanide-based material layer may be formed to have a high thickness because of its good permeability. That is, since the thickness of the buffer layer may be formed by using the lanthanide-based material layer, loss of the organic layer may be prevented even through a sputtering deposition process.

2A to 2E are cross-sectional views illustrating a method of manufacturing an organic light emitting diode according to the present invention.

Referring to FIG. 2A, the reflective film 110 and the first electrode 112 are formed on the substrate 100 through a deposition method such as a sputtering method. The reflective film 110 is formed of a reflective material such as aluminum, and the first electrode 112 is made of transparent conductive material such as TCO (Indum Tin Oxide; ITO), It is formed of IZO (Indum Zinc Oxide).

Referring to FIG. 2B, the hole injection layer 114, the hole transport layer 116, the light emitting layer 122, the electron transport layer 118, and the buffer layer are formed on the substrate 100 on which the reflective film 110 and the first electrode 112 are formed. 120 is formed sequentially.

Specifically, as shown in FIG. 2C, the substrate 100 in which the first electrode 112 and the reflective film 110 are formed, and the organic layer 114a of the material of the hole injection layer 114 are formed in the vacuum chamber 126. A third evaporation source (a second evaporation source (114a '), a second evaporation source (116b') containing an organic layer 116b of the material of the hole transport layer 116, and a third evaporation source containing an organic layer (122c) of the material of the light emitting layer 122 ( 122c '), a fourth evaporation source 118e' containing the organic layer 118e of the material of the electron transport layer 118, and a fifth evaporation source 119f 'containing the lanthanide series 119 material layer. Each of the first to fifth evaporation sources 114a ', 116b', 122c ', 118d', and 119e 'includes a shutter 126a.

As shown in FIG. 2C, the first evaporation source 114a ′ is a hole injection layer in which the organic layer 114a contained in the first evaporation source 114a ′ is vaporized by resistance heating, and evaporated from the first evaporation source 114a ′. A material of 114a is deposited on the substrate 100 to form a hole injection layer 114. Thereafter, as shown in FIG. 2D, the organic layer 116b in which the second evaporation source 116b 'is contained in the second evaporation source 116b' by resistance heating is vaporized, and holes evaporated from the second evaporation source 116b '. The material of the transport layer 116 is deposited on the substrate 100 to form the hole transport layer 116. In this manner, the light emitting layer 122 and the electron transporting layer 118 are sequentially formed.

As shown in FIG. 2E, the material layers 118d and 119e contained in each of the fourth and fifth evaporation sources 118d 'and 119e' are co-deposited on the substrate 100 on which the electron transport layer 118 is formed. The buffer layer may be formed by a deposition process, and the buffer layer may be formed by forming only the lanthanide-based material layer 110e contained in the fifth evaporation source 119e '. In this case, the material of the material layer 119e contained in the fifth evaporation source 119e 'is a liquid of lanthanide series elements, and includes iridium (Ir), lanthanum (La), cerium (Ce), praseodymium (Pr), and neodymium ( Nd, Promethium (Pm), Samarium (Sm), Europium (Eu), Gadolinium (Gd), Terbium (Tb), Dysprosium (Dy), Holmium (Ho), Erbium (Er), Thulium (Tm), Ytterbium ( Yt) and the like, and preferably, iridium (Ir). When the material of the electron transport layer and the lanthanide-based material layer are bonded to each other to form the buffer layer 120, the lanthanide-based material layer is doped at 1 to 50% based on the thickness of the buffer layer 120. Such a buffer layer 120 may be formed to a thickness of 30 ~ 400Å. As described above, the lanthanide series element may have a high thickness because of its good permeability.

Referring to FIG. 2F, a sputtering method and the like on the substrate 100 including the hole injection layer 114, the hole transport layer 116, the light emitting layer 122, the electron transport layer 118, and the buffer layer 120 are formed. Through the deposition method of the second electrode 128 is formed. The second electrode 128 is a conductive film having a permeability and is formed of an alloy such as MgAg, MgIn, AlLi, or the like. As described above, even when the second electrode 128 is formed by the sputtering method, the loss of the organic layer may be prevented by the buffer layer 120. The effect of the present invention on this will be described in detail with reference to [Table 1].

Case 1 shown in Table 1 shows the result of the organic light emitting device having no buffer layer between the electron transport layer and the second electrode, and Case 2 shows organic light emission in which the buffer layer is formed of LiF and Al between the electron transport layer and the second electrode. The results of the device are shown, and Case 3 shows the results of the organic light emitting device having a buffer layer formed of a material layer of ytterbium (lanthanide series) between the electron transport layer and the second electrode.

V cd / A Im / W CIEx CIEy Case 1 8.3 0.3 0.1 0.475 0.515 Case 2 8.3 1.4 0.5 0.464 0.526 Case 3 4.6 21.2 14.4 0.381 0.604

As shown in Table 1, the results of the organic light emitting device of Case 1 without the buffer layer and the organic light emitting device having the buffer layer formed of LiF and Al do not appear to be different from each other. That is, even if the buffer layer is formed of LiF and Al it can be seen that the damage to the organic layer does not actually prevent.

However, in the case of the organic light emitting device having the buffer layer formed of ytterbium (Yb) according to the present invention, as shown in [Table 1], the driving voltage is about twice lower than in Case 1 and Case 2, and in the case of current efficiency. Is 21 times higher. In addition, the power efficiency is also very high, and the color purity is also improved as the value of the color coordinate.

As such, by forming the buffer layer according to the conditions of the present invention, it is possible to exhibit low driving voltage, high current efficiency, power efficiency, and improved color. That is, even when the second electrode is deposited by the sputtering method, it can be seen that the organic layer is not damaged.

3 is an equivalent circuit diagram of an R, G, and B pixel of a display device using an organic light emitting diode according to an exemplary embodiment of the present invention, and FIG. 4 is a cross-sectional view of the display device using the organic light emitting diode illustrated in FIG. 3.

3 and 4, each of the R, G, and B pixels of the display device using the organic light emitting diode according to the exemplary embodiment includes a cell driver and an organic light emitting diode connected to the cell driver. In detail, an R cell driver connected to the gate line GL, the data line DL, and the power supply line PL is connected to the R pixel, a first organic light emitting device connected to the R cell driver, and a gate line is connected to the G pixel. The G cell driver connected to the GL, the data line DL, and the power supply line PL, the second organic light emitting element connected to the G cell driver, and the gate line GL, the data line DL, The B cell driver connected to the power supply line PL and the third organic light emitting device connected to the B cell driver are included. Such a display device may include red (R) light emitted from the light emitting layer of the first organic light emitting element of the R pixel, and green (G) light emitted from the light emitting layer of the organic light emitting element of the second organic light emitting element of the G pixel. The blue (B) light emitted from the light emitting layer of the organic light emitting device of the organic light emitting device is mixed to realize white light. The organic light emitting device according to the embodiment emits full light.

The R cell driver includes a first switch thin film transistor TS1 connected to a gate line GL and a data line DL, a first switch thin film transistor TS1, a power supply line PL, and a first organic light emitting element. A first driving thin film transistor TD1 connected to the first electrode 112, and a storage capacitor C1 connected between the power supply line PL and the drain electrode 138 of the first switch thin film transistor TS1. .

The G cell driver includes a second switch thin film transistor TS2 connected to the gate line GL and the data line DL, a second switch thin film transistor TS2, a power supply line PL, and a second organic light emitting element. A second driving thin film transistor TD2 connected to the first electrode 112, and a storage capacitor C2 connected between the power supply line PL and the drain electrode 158 of the second switch thin film transistor TS2. .

The B cell driver includes a third switch thin film transistor TS3 connected to the gate line GL and the data line DL, a third switch thin film transistor TS3, a power supply line PL, and a third organic light emitting element. A third driving thin film transistor TD3 connected to the first electrode 158, and a storage capacitor C3 connected between the power supply line PL and the drain electrode 178 of the third switch thin film transistor TS3. .

As shown in FIG. 4, the first to third driving thin film transistors TD1 to TD3 include gate electrodes 132, 152, and 172 formed on the insulating substrate 101, gate insulating layers covering the gate electrodes 132, 152, and 172. The source regions 136S, of the semiconductor layers 136, 156, 176 through the semiconductor layers 136, 156, 176 formed on the gate insulating film, the interlayer insulating films covering the semiconductor layers 136, 156, 176, and the first and second contact holes 130, 119, 150, 139, 170, 159 passing through the interlayer insulating films. Source electrodes 134, 154, 174 and drain electrodes 138, 158, 178 connected to the 156S, 176S and drain regions 136D, 156D, 176D, respectively. The semiconductor layers 136, 156, and 176 are formed of an LTPS thin film and overlap the gate electrodes 132, 152, and 172 with the channel regions 136C, 156C, and 176C, and the gate electrodes 132 with the channel regions 136C, 156C, and 176C therebetween. And 152 and 172, which are non-overlapping with impurities, and source regions 136S, 156S and 176S implanted with impurities, and drain regions 136D, 156D and 176D. The present invention has been exemplified that the semiconductor layer is formed of an LTPS thin film, but is not limited thereto.

The first organic light emitting diode includes a bank insulating layer 142 having a reflective film 110 formed on a passivation layer covering the first driving thin film transistor, a first electrode 112, and a pixel hole exposing the first electrode 112. The hole injection layer 114, the hole transport layer 116, the red light emitting layer 122R, the electron transport layer 118, the buffer layer 120, and the second electrode 128 formed on the first electrode 112 exposed through the first electrode 112 are formed. do.

The second organic light emitting diode includes a bank insulating layer 142 having a reflective film 110 formed on a passivation layer covering the second driving thin film transistor, a first electrode 112, and a pixel hole exposing the first electrode 112, and a pixel hole. The hole injection layer 114, the hole transport layer 116, the green light emitting layer 122G, the electron transport layer 118, the buffer layer 120, and the second electrode 128 formed on the first electrode 112 exposed through the first electrode 112 are formed. do.

The third organic light emitting diode includes a bank insulating layer 142 having a reflective film 110 formed on a passivation layer covering the third driving thin film transistor, a first electrode 112, and a pixel hole exposing the first electrode 112, and a pixel hole. The hole injection layer 114, the hole transport layer 116, the blue light emitting layer 122B, the electron transport layer 118, the buffer layer 120, and the second electrode 128 formed on the first electrode 112 exposed through the first electrode 112 are formed. do.

The buffer layer 120 included in the first to third organic light emitting diodes may be formed of a lanthanide-based material layer or co-deposition of an electron transport layer and a lanthanide-based material layer. The buffer layer 120 serves as an electron injection layer and protects the organic layer during the deposition process.

Lanthanide-based elements include ytterbium (Yb), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), and gadolinium (Gd). ), Terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), and the like, and preferably formed of ytterbium (Yb).

When formed covalently with the material of the lanthanide-based material layer and the electron transport layer, the lanthanide-based material layer is doped at 1 to 50% based on the thickness of the buffer layer. The buffer layer 120 may be formed to have a thickness of 30 μs to 400 μs. As described above, the lanthanide-based material layer may be formed to have a high thickness because of its good permeability. That is, since the thickness of the buffer layer may be formed by using the lanthanide-based material layer, loss of the organic layer may be prevented even through a sputtering deposition process.

5A through 5D are cross-sectional views illustrating a method of manufacturing a display device according to an exemplary embodiment of the present invention illustrated in FIG. 4.

Referring to FIG. 5A, inorganic and organic passivation layers including gate electrodes 132, 152, 172, gate insulating layers, semiconductor layers 136, 156, 176, source electrodes 134, 154, 174, drain electrodes 138, 158, 178, and pixel holes are formed on the substrate 101. The thin film transistor, the reflective film 110 and the first electrode 112 connected to the drain electrodes 138, 158, and 178 of the thin film transistor are formed.

Specifically, the first electrode 112 on the substrate 101 on which the thin film transistor is formed is a metal material having a high reflectance such as aluminum (Al), silver (Ag), molybdenum (Mo), and ITO (Indum Tin Oxide; Transparent material such as ITO) is formed by a deposition method such as sputtering or the like. The reflective film 112 is formed of a reflective material such as aluminum. The first electrode 112 is connected to the drain electrodes 138, 158, and 178 of the thin film transistor through the reflective film 110.

Referring to FIG. 5B, a bank insulating layer 142 having pixel holes is formed on the substrate 101 on which the reflective film 110 and the first electrode 112 are formed.

Referring to FIG. 5C, the hole injection layer 114, the hole transport layer 116, the light emitting layers 122R, 122G, and 122B, and the electron transport layer may be formed on the substrate 101 on which the reflective film 110 and the first electrode 112 are formed. 118, the buffer layer 120 is sequentially formed. The method of manufacturing the hole injection layer 114, the hole transport layer 116, the light emitting layers 122R, 122G, and 122B, the electron transport layer 116, and the buffer layer 120 is illustrated in the embodiment of the present invention illustrated in FIGS. 2C to 2E. Since it is the same as the organic light emitting device according to the description will be omitted. The method of forming the buffer layer 120 is also the same as the method of forming the buffer layer shown in FIG. 2E and will be omitted.

Referring to FIG. 5D, a sputtering method may be performed on a substrate on which an organic layer including a hole injection layer 114, a hole transport layer 116, light emitting layers 122R and 122G and 122B, an electron transport layer (not shown), and a buffer layer 120 is formed. The second electrode 128 is formed through the deposition method. The second electrode 128 is a conductive film having a permeability and is formed of an alloy such as MgAg, MgIn, AlLi, or the like. Even when the second electrode 128 is formed through a sputtering method, damage to the organic layer may be prevented by the buffer layer 120.

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: substrate 110: reflecting film
112: first electrode 114: hole injection layer
116 hole transport layer 122 light emitting layer
118: electron transport layer 120: buffer layer
128: second electrode

Claims (10)

Forming a reflective film and a first electrode on the substrate;
Forming an organic layer including a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and a buffer layer on the substrate on which the reflective film and the first electrode are formed;
Forming a second electrode on the substrate on which the organic layer is formed;
The buffer layer may be formed of a lanthanide-based material layer, or may be formed by co-depositing an electron transport layer and a lanthanide-based material layer. The method of claim 1,
The lanthanide series is ytterbium (Yb), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd) And terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), and thulium (Tm). The method of claim 1,
The buffer layer is a method of manufacturing an organic light emitting device, characterized in that formed of ytterbium (Yb) of the lanthanide series. The method of claim 1,
When the electron transport layer and the lanthanide-based material layer are bonded to each other to form a buffer layer, the lanthanide-based material layer is doped at 1 to 50% based on the thickness of the buffer layer. Way. The method of claim 1,
The buffer layer is a method of manufacturing an organic light emitting device, characterized in that formed in a thickness of 30 ~ 400Å. Forming a thin film transistor on the substrate;
Forming a reflective film and a first electrode to be connected to the drain electrode of the thin film transistor;
Forming an organic layer including a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and a buffer layer on the first electrode;
Forming a second electrode on the substrate on which the organic layer is formed;
The buffer layer may be formed of a lanthanide-based material layer or formed by co-depositing an electron transport layer and a lanthanide-based material layer. The method of claim 6,
The lanthanide series is ytterbium (Yb), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd) And terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), and thulium (Tm). The method of claim 6,
And wherein the buffer layer is formed of iridium in the lanthanide series. The method of claim 6,
When the electron transport layer and the lanthanide-based material layer are bonded to each other to form a buffer layer, the lanthanide-based material layer is doped at 1 to 50% based on the thickness of the buffer layer. Method for manufacturing a display device. The method of claim 6,
The buffer layer is a manufacturing method of a display device using an organic light emitting element, characterized in that formed in a thickness of 30 ~ 400Å.

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