KR100673753B1 - Organic Emission Light Device - Google Patents

Abstract

The present invention relates to an organic light emitting device comprising an anode electrode formed on a substrate, a light emitting layer formed on the anode electrode, and a cathode electrode formed on the light emitting layer. The anode electrode is one selected from the group consisting of a first reflective conductive layer coated with a metal selected from the group consisting of aluminum and aluminum alloy on the substrate, and lanthanide and actinium-based elements on the first reflective conductive layer And a second reflective conductive layer formed of silver (silver alloy) alloyed with the above metals, and an upper conductive layer formed of a conductive metal oxide on the second reflective conductive layer.

As such, by forming a multilayer anode electrode including the first reflective conductive layer having good adhesion and the second reflective conductive layer having good reflectivity, not only can the productivity of the anode electrode be improved but also the reflectance can be increased to increase the luminance of light emitted. have.

Anode, first reflective conductive layer, second reflective conductive layer, lanthanum series, actinium series, organic light emitting device

Description

Organic Emission Light Device

1 is a schematic side cross-sectional view of an organic light emitting diode including an anode according to an embodiment of the present invention.

2 is a schematic block diagram for forming an anode electrode according to the present invention.

3A to 3C are manufacturing process diagrams of the anode electrode according to FIG. 2.

4 is a graph showing reflectances of a single layer anode electrode and a multilayer anode electrode.

5A is a diagram illustrating the adhesion of silver coated on a substrate according to JIS standards, and FIG. 5B is a diagram illustrating the adhesion of ATD alloys coated on a substrate according to JIS standards.

♣ Explanation of symbols for the main parts of the drawing ♣

100 organic light emitting device 110 substrate

120: anode electrode 121: first reflective conductive layer

122: second reflective conductive layer 123: upper conductive layer

130: hole injection layer 140: hole transport layer

150: light emitting layer 160: electron transport layer

170: electron injection layer 180: cathode

The present invention relates to an organic light emitting device, and more particularly, to an organic light emitting device including an anode electrode which improves productivity by increasing contact force with a substrate and employs a reflective conductive material having high reflectance to improve luminous efficiency. .

In general, an organic light emitting device includes a pair of electrodes consisting of an anode and a cathode, a hole injection layer, a hole transport layer, a light emitting layer, an electron injection layer, It is a structure including an electron transport layer. The organic light emitting device having such a structure emits light as electrons and holes from the anode electrode and the cathode electrode are injected into the light emitting layer. More specifically, holes are injected into the hole injection layer from the anode, and holes injected into the hole injection layer are transported to the light emitting layer by the hole transport layer. In the electron injection layer, electrons are injected from the cathode electrode, and electrons injected into the electron injection layer are transported to the light emitting layer by the electron transport layer. Holes and electrons carried in the light emitting layer combine with each other to form excitation electrons, whereby light is generated in the light emitting layer.

The anode electrode constituting the organic light emitting device described above is formed in a single layer using a reflective conductive material. For example, the anode has a high work function in the direction of light emission and is an electrode formed of transparent conductive metal oxides (ITO, IZO, etc.). Anodes formed of ITO and IZO can emit light generated in the light emitting layer to the outside due to their transparency.

However, such a conductive metal oxide has a disadvantage in that luminous efficiency is lowered because the work function decreases with time. In order to solve this problem, it has been proposed to form an anode electrode using a reflective metal material, for example, aluminum, silver, and an alloy mainly composed of them. However, when the anode electrode is formed of aluminum or aluminum alloy, since the reflectance of aluminum is about 90%, it is not easy to reflect all the light emitted from the light emitting layer, which causes a problem of low luminous efficiency. On the other hand, when the anode is formed using silver or silver alloy having a reflectance of 98% or more, the reflectance is better than that of other metals, but the ionized metal is melted or transferred because of its poor water resistance. Moreover, since silver has poor adhesion, there is a problem that it is not easy to form on a specific substrate, for example, a substrate such as acrylic or oxide oxide.

As an invention devised to solve the conventional problems of the present invention, a first object of the present invention is to provide an organic light-emitting device comprising an anode electrode which can improve the reflectance and light utilization by forming the anode electrode in multiple layers. .

In addition, a second object of the present invention is to provide an organic light emitting device capable of improving productivity of an anode electrode by using a conductive metal material capable of improving water resistance or adhesion.

According to an aspect of the present invention for achieving the above object, the present invention is an organic material comprising an anode electrode formed on the substrate, a light emitting layer formed on the anode electrode, and a cathode electrode formed on the light emitting layer It relates to a light emitting device. The anode of the organic light emitting device includes a first reflective conductive layer coated with a metal selected from the group consisting of aluminum and an aluminum alloy on the substrate, and lanthanide and actinium based elements on the first reflective conductive layer. And a second reflective conductive layer formed of silver (silver alloy) alloyed by adding one or more metals selected from the group consisting of, and an upper conductive layer formed of a conductive metal oxide on the second reflective conductive layer. The silver alloy may contain samarium at 0.1 to 0.6 at% (atomic percent), and may further include terbium, and may be added at 0.4 to 1 at% (atomic percent) to the silver alloy of terbium. Do.

Preferably, the silver alloy further comprises at least one metal of gold or copper. The metal material constituting the first reflective conductive layer is a metal material having better adhesion than the silver alloy forming the second reflective conductive layer. Most preferably, the first reflective conductive layer is aluminum or an alloy mainly composed of aluminum. The thickness of the second reflective conductive layer is formed to be thinner or the same as the thickness of the first reflective conductive layer. The one selected from the group consisting of the gold, copper, and a mixture of gold and copper added to the silver alloy is preferably included in 0.4 to 1 at% (atomic percent).

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

1 is a schematic side cross-sectional view of an organic light emitting device including an anode according to an embodiment of the present invention. Referring to FIG. 1, the organic light emitting diode 100 includes a substrate 110, an anode electrode 120 formed on the substrate 110, and a hole injection layer 130 formed on the anode electrode 120. And a hole transport layer 140, a light emitting layer 150, an electron transport layer 160, an electron injection layer 170, and a cathode electrode 180.

The organic light emitting diode 100 having the above-described configuration emits light based on the following principle. First, holes are injected from the anode electrode 120 into the hole injection layer 130, and holes injected into the hole injection layer 130 are transported to the light emitting layer 150 by the hole transport layer 140. Next, electrons are injected from the cathode electrode 180 into the electron injection layer 170, and electrons injected into the electron injection layer 170 are transported to the light emitting layer 150 by the electron transport layer 160. Holes and electrons transported to the light emitting layer 150 combine with each other to form excitation electrons, and thus light is generated in the light emitting layer 150.

More specifically, the anode electrode 120 includes a first reflective conductive layer 121 formed on the substrate 110, a second reflective conductive layer 122 formed on the first reflective conductive layer, and a second The upper conductive layer 123 is formed on the reflective conductive layer 122.

2 is a schematic block diagram for forming an anode electrode according to the present invention, Figures 3a to 3c is a process chart for manufacturing an anode electrode according to the present invention.

Referring to FIG. 2, the process of forming the anode electrode 120 of the present invention starts at step S21 of preparing a substrate 110 made of glass or organic material. In a next step (S22), the first reflective conductive layer 121 is formed on the substrate 110 through an arbitrary deposition process such as a sputtering process (see FIG. 2A). In this embodiment, the first reflective conductive layer 121 may be formed of aluminum or an alloy mainly composed of aluminum. Aluminum (Al) has a relatively high reflectance (approximately 90% or more), and since adhesive strength is also relatively good compared to other metals, it is easy to form directly on the substrate 110.

In step S23, a second reflective conductive layer 122 is formed on the first reflective conductive layer 121 (see FIG. 2B). The second reflective conductive layer 122 includes lanthanum series (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) and actinium series (Ac, Th, It is formed of a silver alloy containing at least one metal of the elements of Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, Lr). In addition, the silver alloy forming the second reflective conductive layer 122 further includes at least one metal of gold or copper in at least one metal selected from lanthanum and actinium. Since the second reflective conductive layer 122 is formed to be the same as or thinner than the first reflective conductive layer 121, the amount of silver used may be reduced as compared with the conventional anode electrode.

Hereinafter, the silver alloy having the above-described configuration, that is, a silver alloy formed of a metal selected from the lanthanum series and the actinium series, gold and copper, is called an ATD alloy. In the present exemplary embodiment, the second reflective conductive layer 122 uses an ATD alloy including samarium (Sm), terbium (Tb), gold (Au), and copper (Cu) selected from lanthanum and actinium. At this time, it is preferable that samarium is added in an amount of 0.1 to 0.6 at% (at: atomic percent), terbium, gold, and copper in 0.4 to 1 at%, respectively. Most preferably, samarium is added at 0.3 at%.

In a next step S24 in which the second reflective conductive layer 122 is formed, the upper conductive layer 123 is provided on the second reflective conductive layer 122 (see FIG. 2C). The upper conductive layer 123 is preferably formed on the entire surface of the second reflective conductive layer 122 for uniformity of the entire anode electrode 120. The upper conductive layer 123 has a certain degree of transparency and can be sufficiently used as long as it is a conductive material sufficient to be used as an electrode for an electro-optic material. However, in the present embodiment, the upper conductive layer 123 is formed of a semi-transparent conductive metal oxide such as ITO and IZO. Form. In addition, the upper conductive layer 123 may be formed of amorphous-ITO, and the upper conductive layer formed of amorphous-ITO also has excellent adhesion and thermal characteristics. The upper conductive layer 123 is preferably formed relatively thinner than the thicknesses of the first and second reflective conductive layers 121 and 122 in order to prevent the original color purity of the light emitted from the light emitting layer 150 from dropping.

4 is a graph (a) showing the reflectance of the single layer anode electrode and (b) showing the reflectance of the multilayer anode electrode.

Referring to FIG. 4, the graph (a) shows the reflectivity of a single layer anode electrode formed of aluminum alloy with a thickness of 1000 mW. Graph (b) shows the reflectance of the anode electrode comprising a first reflective conductive layer formed of aluminum alloy with a thickness of 500 mV and a second reflective conductive layer formed of ATD alloy with a thickness of 500 mW over the first reflective conductive layer. In other words, in the case of a single layer anode electrode formed of an aluminum alloy, light emitted from the light emitting layer reflects the reflectance of aluminum. On the other hand, in the case of a multilayer anode electrode formed of an aluminum alloy / ATD alloy, the first reflection is performed by the reflectance of the ATD alloy and then the second reflection is performed by the reflectance of the aluminum alloy. In conclusion, as shown in graphs (a) and (b), the reflectance of the multilayer anode electrode is about 10% higher than that of the single layer anode electrode. As such, when the reflectance of the anode electrode is improved by 10% or more, the organic light emitting device can provide an improvement in luminance of light emitted over the improved reflectance at the anode electrode.

5A and 5B are diagrams illustrating the adhesion between the silver alloy and the ATD alloy according to JIS standards. 5A is a JIS test when silver alloy is applied onto a substrate, and FIG. 5B is a JIS test when ATD alloy is applied onto a substrate. JIS adhesion test means that a reflective conductive layer is applied onto a substrate, and then adhered to the upper surface of the substrate on which the reflective conductive layer is applied, using an adhesive tape or the like, and the tape is removed after a predetermined time elapses. It is an experiment showing the degree of removal of the conductive layer. Referring to FIG. 5A, all of the silver applied on the substrate is buried in the tape and does not remain on the substrate (area ⓐ). Referring to FIG. 5B, the ATD alloy remains on the substrate even after the JIS standard test (area ⓑ).

In the present exemplary embodiment, an anode electrode having different thicknesses of the first reflective conductive layer and the second reflective conductive layer is disclosed, but a multilayer anode electrode having the same thickness of the first reflective conductive layer and the second reflective conductive layer may be formed. In particular, the second reflective conductive layer may be formed relatively thinner than the first reflective conductive layer.

In addition, the present embodiment discloses an anode electrode including an aluminum alloy / ATD alloy, but an anode electrode including an aluminum / ATD alloy may be used, and also has a relatively good reflectivity compared to other metals other than aluminum. An anode electrode may be formed using a metal material.

In the present embodiment, only the process of forming the anode electrode of the organic light emitting device is disclosed, but in order to manufacture the organic light emitting device, a process of forming a hole injection layer and a hole transport layer after the anode electrode is formed, the process of forming a light emitting layer, A process of forming an electron transport layer and an electron injection layer and a process of forming a cathode are followed.

As mentioned above, although preferred embodiment of this invention was described in detail, this invention is not limited to the said embodiment, A various deformation | transformation by a person of ordinary skill in the art within the scope of the technical idea of this invention is carried out. This is possible.

As described above, according to the present invention, by forming the anode electrode to include the first reflective conductive layer and the second reflective conductive layer, it is possible to improve the reflectance compared to the single layer anode electrode, thereby improving the light emission luminance. Provide the effect.

In addition, the present invention can solve the problem of adhesion of the reflective conductive layer by forming an anode using a first reflective conductive layer containing aluminum and a second reflective conductive layer of ATD alloy having a high reflectance. The productivity of the anode electrode can be improved.

In addition, the present invention can provide the effect of reducing the material cost compared to the anode electrode formed using the conventional silver by forming the first reflective conductive layer, and then the second reflective conductive layer of the ATD alloy. have.

Claims (11)

An organic light emitting device comprising an anode electrode formed on a substrate, a light emitting layer formed on the anode electrode, and a cathode electrode formed on the light emitting layer. The anode electrode, A first reflective conductive layer formed of a metallic material capable of reflecting light emitted from the light emitting layer on the substrate; A second reflective conductive layer formed of silver (silver alloy) alloyed by adding at least one metal selected from the group consisting of lanthanide and actinium series elements on the first reflective conductive layer; An upper conductive layer formed of a conductive metal oxide on the second reflective conductive layer Organic light emitting device comprising a. The method of claim 1, The silver alloy further comprises one selected from the group consisting of gold, copper, and a mixture of gold and copper. The method of claim 1, And the first reflective conductive layer has higher adhesion to the substrate than the second reflective conductive layer. The method of claim 3, The metal material is an organic light emitting device which is aluminum or an alloy mainly composed of aluminum. The method of claim 1, The thickness of the second reflective conductive layer is formed to be thinner or the same as the thickness of the first reflective conductive layer. The method of claim 1, The silver alloy is an organic light emitting device containing samarium (samarium). The method of claim 6, The silver alloy is an organic light emitting device containing the samarium in 0.1 to 0.6 at% (atomic percent). The method of claim 6, The silver alloy further comprises terbium (Terbium). The method of claim 8, The silver alloy is an organic light emitting device containing the terbium 0.4 to 1 at% (atomic percent). The method of claim 2, The silver alloy is an organic light emitting device containing one selected from the group consisting of gold, copper, and a mixture of gold and copper in 0.4 to 1 at% (atomic percent). The method of claim 1, And an electron injection layer and an electron transport layer formed on the anode electrode, and a hole injection layer and a hole transport layer formed on the light emitting layer.

Images