TW201628229A - Organic light emitting diode device and manufacturing method thereof - Google Patents

Abstract

The present invention provides an organic light emitting diode device and a manufacturing method thereof. The organic light emitting diode device comprises a substrate, a transparent conductive layer, an organic light emitting unit and an electrode sequentially disposed from near the substrate to away from the substrate. The transparent conductive layer comprises a first transparent conductor and several second transparent conductors having different refraction indexes. The first transparent conductor has a light output surface facing the substrate and a light input surface facing the organic light emitting unit. The light input surface has a base area and several concave areas which are separated from each other and recessed from the base area toward the light output surface. The second transparent conductors are respectively disposed in the concave areas. Thus, the present invention increases the refraction and reflection interfaces within the transparent conductive layer, so as to improve the light refraction and reflection effects and further effectively enhance the light extraction efficiency.

Description

Organic light emitting diode device and method of manufacturing same

The present invention relates to a light-emitting device and a method of fabricating the same, and more particularly to an organic light-emitting diode device and a method of fabricating the same.

A general organic light emitting diode device generally comprises a transparent substrate, and a transparent conductive layer, an organic light emitting unit and a metal electrode arranged in sequence adjacent to the substrate.

The organic light emitting unit can be driven to project light toward the transparent conductive layer, and finally the light is emitted outward from the transparent substrate for use. However, in terms of the light generated by the organic light-emitting unit, about 80% of the light is trapped on the surface of the metal electrode, and the transparent substrate or transparent conductive layer having a refractive index mismatch, resulting in actually less than 20%. Light can be emitted from the transparent substrate for use. When the proportion of light trapped in the internal components of the organic light-emitting diode device is higher, the amount of light emitted from the internal components of the organic light-emitting diode device is lower, so the existing organic light-emitting The light extraction efficiency of the diode device is low.

In addition, in order to increase the light extraction efficiency to increase the proportion of light that can be emitted from the transparent substrate, the refractive index of the film of the permeable element is changed or the light guiding microstructure and the scattering center are formed, thereby increasing the trapped light. The probability that the line is being exported. The light guiding microstructure is specifically formed by forming a photonic crystal or a grating structure on the transparent conductive layer by a process such as lithography or nano transfer, and then forming an organic light emitting unit on the photonic crystal or the grating structure. Although the foregoing method can improve the light extraction efficiency, the process of the technology is complicated, and the light guiding microstructure prepared must be in contact with the organic light emitting unit, thereby causing insufficient stability of the bonding between the light guiding microstructure and the organic light emitting unit. And reducing the overall reliability of the organic light emitting diode device.

Accordingly, it is an object of the present invention to provide an organic light emitting diode device capable of improving light extraction efficiency and a method of fabricating the same.

Thus, the organic light-emitting diode device of the present invention comprises: a substrate, and a transparent conductive layer, an organic light-emitting unit and an electrode arranged in sequence from adjacent to the substrate. The transparent conductive layer comprises: a first transparent conductor and a plurality of second transparent conductors.

The first transparent conductor has a light-emitting surface facing the substrate and a light-incident surface facing the organic light-emitting unit. The light incident surface has a base region, and a plurality of recessed regions spaced apart from each other and recessed from the base region toward the light exiting surface, respectively. The second transparent conductors are respectively disposed in the recessed regions, and the second transparent conductors have a refractive index different from that of the first transparent conductors.

A method of fabricating an organic light-emitting diode device of the present invention comprises: forming a first transparent conductor on a substrate, the first transparent conductor having a light-emitting surface facing the substrate, and a back surface a light incident surface of the plate; etching the light incident surface of the first transparent conductor such that the light incident surface forms a base region, and a plurality of concave regions spaced apart from each other and recessed from the base region toward the light exit surface; Forming a plurality of second transparent conductors having a refractive index different from the first transparent conductors in the recessed regions; forming an organic light emitting unit on the first transparent conductors and the second transparent conductors; An electrode is formed on the base light emitting unit.

The effect of the present invention is that the concave portions are formed on the light incident surface of the first transparent conductor, and the second transparent conductors are respectively formed in the recessed regions, and then the The refractive index of the second transparent conductor is different from the refractive index of the first transparent conductor. By the improved design of the foregoing innovation, the interface of refraction and reflection of light in the transparent conductive layer can be increased, and the refraction effect and reflection effect of the light in the transparent conductive layer can be improved, thereby effectively improving the light extraction efficiency.

1‧‧‧Substrate

2‧‧‧Transparent conductive layer

21‧‧‧First transparent conductor

211‧‧‧Glossy

212‧‧‧Into the glossy surface

213‧‧‧ base area

214‧‧‧ recessed area

215‧‧‧ Groove

22‧‧‧Second transparent conductor

221‧‧‧ arc convex

222‧‧‧flat surface

29‧‧‧Transparent conductive material

3‧‧‧Organic lighting unit

4‧‧‧Electrode

5‧‧‧mask layer

51‧‧‧Opening

D‧‧‧ Depth of depression

81~85‧‧‧Steps

Other features and advantages of the present invention will be apparent from the embodiments of the present invention. FIG. 1 is a partial cross-sectional view of an embodiment of the organic light emitting diode device of the present invention; A schematic flow chart of a step of an embodiment of a method for fabricating an organic light-emitting diode device; FIG. 3 is a block diagram of a step of the manufacturing method; Figure 4 is a plot of voltage versus current efficiency.

Before the present invention is described in detail, it should be noted that in the following description, similar elements are denoted by the same reference numerals.

Referring to FIG. 1 , an embodiment of an organic light emitting diode device of the present invention comprises: a substrate 1 and a transparent conductive layer 2 , an organic light emitting unit 3 and an electrode 4 disposed adjacent to and away from the substrate 1 . .

The substrate 1 is made of a light transmissive material, specifically glass or plastic.

The transparent conductive layer 2 includes a layered first transparent conductor 21 and a plurality of second transparent conductors 22 embedded in the first transparent conductor 21.

The first transparent conductor 21 has a light-emitting surface 211 facing the substrate 1 and a light-incident surface 212 facing the organic light-emitting unit 3. The light incident surface 212 has a flat base region 213 and a plurality of concave regions 214 spaced apart from each other and recessed by the base region 213 toward the light exit surface 211, respectively.

In this embodiment, the recessed depth d of the recessed regions 214 is 50-200 nm, and the recessed depth d is a depth recessed from the base region 213 toward the light-emitting surface 211 along a direction perpendicular to the base region 213. The area of the concave area 214 projected onto the light-emitting surface 211 is 7 to 30% of the area projected by the light-incident surface 212 onto the light-emitting surface 211. As for the meaning of the above numerical definition, it will be described later.

The second transparent conductors 22 are respectively disposed in the recessed regions 214, and each of the second transparent conductors 22 has an arcuate surface 221 that fits the corresponding recessed region 214, and a tangent region 213 Flat face 222.

The refractive indices of the second transparent conductors 22 are different from the refractive indices of the first transparent conductors 21. In practice, the material of the first transparent conductor 21 may specifically be indium tin oxide (ITO); the material of the second transparent conductor 22 may specifically be aluminum zinc oxide (AZO), indium zinc oxide (IZO) or Manganese oxide zinc oxide (MZO), these materials have a higher refractive index than indium tin oxide.

The organic light emitting unit 3 is disposed on the base region 213 and the flat surfaces 222, and can be driven to emit light toward the transparent conductive layer 2. The electrode 4 cooperates with the transparent conductive layer 2, thereby outputting electric energy to the organic light emitting unit 3 to drive the organic light emitting unit 3.

In practice, the organic light emitting unit 3 may include an anode buffer layer, a hole transport layer (HTL), and an emitter layer (the emitter layer) sequentially arranged from the transparent conductive layer 2 toward the electrode 4. Layer) with an electron transport layer (ETL). The emitter layer is made of an organic material, and the material of the electrode 4 is a metal. Since the substrate 1, the organic light-emitting unit 3 and the electrode 4 are conventional materials and structures, and are not the focus of improvement of the present invention, they will not be described in detail herein.

1 , 2, and 3, an embodiment of the organic light-emitting diode device of the present invention includes the following steps: Step 81: forming the first transparent conductive body 21 on the substrate 1 to make the first transparent conductive body 21 The light emitting surface 211 faces the substrate 1 The light incident surface 212 faces away from the substrate 1. In practice, the first transparent conductor 21 can be formed by, for example, physical or chemical vapor deposition.

Step 82: etching the light incident surface of the first transparent conductor 21 212, the light incident surface 212 is formed into the base region 213 and the concave regions 214 which are separated from each other and are respectively recessed from the base region 213 toward the light exit surface 211.

In this embodiment, specifically, the light lithography is first transmitted. In the (Photolithography) method, a mask layer 5 is formed on the light incident surface 212 of the first transparent conductor 21, and the mask layer 5 is formed into a plurality of openings 51 through which the light incident surface 212 is exposed. Next, the light incident surface 212 of the first transparent conductor 21 is etched by wet etching. The portion of the light incident surface 212 corresponding to the opening 51 is etched and recessed toward the light exit surface 211 to form the concave regions 214. The portion of the light incident surface 212 covered by the mask layer 5 can be protected. This base region 213 is flat. Finally, etching to the recessed regions 214 is such that the recess depth d is 50 to 200 nm, and the mask layer 5 is removed. At this time, each of the recessed areas 214 defines a recess 215.

Step 83: respectively in the recess 215 of the recessed area 214 The second transparent conductors 22 having a refractive index different from that of the first transparent conductor 21 are formed.

In this embodiment, specifically, for example, physical or chemical a transparent conductive material 29 is formed on the light incident surface 212 by a vapor deposition method, and the transparent conductive material 29 is simultaneously placed against the base region 213 and protrudes into the recesses 215 to be placed in the same manner. Recessed area 214. Then, the portion of the transparent conductive material 29 that abuts against the base region 213 is removed by a chemical mechanical polishing (CMP) method. At this time, the transparent conductive material 29 protrudes into the grooves 215 and is attached. The second transparent conductors 22 are formed by the recessed regions 214.

In addition, the transparent conductive material 29 is removed from the base region 213. In some cases, the second transparent conductors 22 are aligned to the base region 213, so that each of the second transparent conductors 22 forms the arcuate surface 221 of the corresponding recessed region 214 and the base region 213 is cut. The flat surface 222.

Step 84: at the first transparent conductor 21 and the second The organic light emitting unit 3 is formed on the transparent conductor 22.

Step 85: forming the electrode on the organic light emitting unit 3 4.

Since the organic light emission can be formed by a conventional means during implementation The unit 3 and the electrode 4, and the foregoing means are not the focus of the improvement of the present invention, and therefore will not be described in detail herein.

Referring to FIG. 1, in use, when the organic light emitting unit 3 is When the light is projected toward the transparent conductive layer 2, part of the light enters from the base region 213 of the light incident surface 212 of the first transparent conductive body 21. Among the light rays, some of the light passes vertically through the first portion. The transparent conductive body 21 and the substrate 1 can be emitted outwardly, and some light enters the first transparent conductive body 21 at an angle with the base region 213, and when projected into the concave regions 214, The refractive index of the second transparent conductor 22 is different from the refractive index of the first transparent conductor 21, thereby generating a reflection effect, so that the light can be folded toward the middle and emitted outward toward the substrate 1, reducing the first transparent conductor. The total reflection between the substrate 21 and the substrate 1 can thereby improve the light extraction efficiency.

On the other hand, when the organic light emitting unit 3 is driven toward the When the transparent conductive layer 2 projects light, another portion of the light enters from the flat surface 222 of the second transparent conductor 22, and the light from the portion is emitted from the arcuate surface 221 of the second transparent conductor 22 and enters. When the concave portion 214 of the first transparent conductor 21 is used, the refractive index of the second transparent conductor 22 is different from the refractive index of the first transparent conductor 21, so that some light has a refraction effect and some light has a reflection effect. More light is scattered between the interface of the second transparent conductor 22 and the first transparent conductor 21 (ie, the arcuate surface 221, the concave regions 214), so that the light is folded toward the middle and can be directed toward The substrate 1 is emitted outward to reduce total reflection between the first transparent conductor 21 and the substrate 1, so that light extraction efficiency can be improved.

As can be seen from the above description, the first transparent conductor 21 is transmitted through the first transparent conductor 21 The concave surface 214 is formed on the light incident surface 212, and the second transparent conductive bodies 22 are respectively formed in the recesses 215 defined by the concave regions 214, and the second transparent conductors are matched. The refractive index of the electrical conductor 22 is different from the refractive index of the first transparent electrical conductor 21. By the improved design of the foregoing innovation, the interface of the refraction and reflection of light in the transparent conductive layer 2 can be increased, and the refraction and reflection effect of the light in the transparent conductive layer 2 can be improved, so that the light can be directed toward the substrate 1. It is shot out, which effectively improves the light extraction efficiency.

This is because the refractive indices of the second transparent conductors 22 are different. The refractive index of the first transparent conductor 21 is such that the light emitted by the organic light-emitting unit 3 in the second transparent conductor 22 is folded in the middle, and is utilized in the first transparent conductor 21 and the first The scattering effect of the interface of the two transparent conductors 22 makes it easier to derive light from the substrate 1. On the other hand, when the transparent conductive layer 2 is not provided with the second transparent conductors 22 When the incident angle of the light entering the first transparent conductor 21 is greater than the total reflection angle of the interface between the first transparent conductor 21 and the substrate 1, total reflection will occur. For this reason, the present embodiment transmits the first The second transparent conductive body 22 is embedded in the transparent conductive body 21, so that part of the light is reflected by the interface between the first transparent conductive body 21 and the second transparent conductive body 22, thereby changing the light path and being derived from the substrate 1. Therefore, the light extraction efficiency can be improved.

The light extraction rate according to the present invention means the organic light emitting unit 3 of all the light emitted by the light, which can be projected through the transparent conductive layer 2 and the substrate 1 for use. The higher the light extraction rate, the higher the amount of light that is emitted outwardly from the internal components of the organic light-emitting diode device.

Referring to Figures 1, 2, and 3, preferably, this embodiment also enables such The flat surface 222 of the second transparent conductor 22 is aligned with the base region 213 of the first transparent conductor 21, thereby forming the transparent conductive layer 2 as a whole to form a flat surface, which may facilitate the organic light emitting unit 3 in step 84. The arrangement can improve the bonding stability between the two and improve the reliability of the organic light-emitting diode device as a whole.

Preferably, the recess depth d of the recessed regions 214 is 50~200nm. When the recess depth d of the recessed regions 214 is less than 50 nm, the recessed regions 214 are insufficiently recessed, which will reduce the refraction effect and the reflection effect, and the improved light extraction efficiency is limited. When the recess depth d of the recessed regions 214 is greater than 100 nm, the recessed portions 214 are excessively recessed, which causes the cross section of the first transparent conductor 21 to be too small, and the resistivity is high. The volume of the two transparent conductors 22 increases, Thereby, the electrical resistance of the entire transparent conductive layer 2 is increased.

Preferably, the concave regions 214 are projected onto the light exit surface 211 The area of the light incident surface 212 is 7 to 30% of the area projected onto the light exit surface 211. When the ratio of the area of the concave portion 214 projected to the light-emitting surface 211 is less than 7%, the proportion of the light-incident surface 212 forming the concave regions 214 is insufficient, so that the refractive effect and the reflection effect are reduced, thereby Can not effectively improve the efficiency of light extraction. When the ratio of the area of the concave portion 214 projected to the light-emitting surface 211 is greater than 30%, the ratio of the light-incident surface 212 forming the concave regions 214 is too high, which will result in a higher resistivity. The two transparent conductors 22 increase in volume, thereby increasing the overall electrical resistance of the transparent conductive layer 2.

The effects of the present invention are further illustrated by experiments below.

The layer structure of the organic light-emitting diode device of the experimental examples 1 to 4 is as shown in FIG. 1. The difference between the experimental examples 1 and 4 is that the area of the concave portion 214 projected onto the light-emitting surface 211 accounts for the light entering the light. The ratio of the area 212 projected to the area of the light exit surface 211. Experimental Example 1 was 7.9%, and Experimental Example 2 was 14.1%, 20.9%, and 27.7%.

On the other hand, the transparent conductive layer 2 of the comparative example has only the first transparent conductive body 21, and the second transparent conductive body 22 as in the present case is not embedded on the first transparent conductive body 21, which is also a general organic light-emitting diode 2. The structure of the polar body device. In other words, since the light incident surface 212 of the first transparent conductor 21 of the comparative example does not form the concave regions 214, the proportion of the light incident surface 212 of the comparative example forming the concave regions 214 is 0%.

Referring to Figures 1, 4, Figure 4 is a voltage (unit: V) and current The relationship diagram of the efficiency (unit cd/A) mainly applies different voltages to the experimental examples 1 to 4 and the comparative examples, thereby observing the current efficiency. The other structures are the same except that the structure of the transparent conductive layer 2 is different, and the addition of the second transparent conductive body 22 causes an increase in the overall resistance of the transparent conductive layer 2. Therefore, the higher the current efficiency, the same. Under the internal luminous efficiency, the higher the brightness of the external light, the higher the light extraction efficiency.

It can be seen from the experimental results that when the voltage is raised to 2V or higher After that, Experimental Examples 1 to 4 generally exhibited higher current efficiencies, and the current efficiencies of Experimental Examples 1 to 4 were higher than those of Comparative Examples when the voltage was raised to 3.3 V or higher.

It can be seen that compared to the general organic light emitting diode device (i.e., the comparative example), the present invention can indeed improve the light extraction rate, because in the present case, the concave regions 214 are formed on the light incident surface 212 of the first transparent conductor 21, and in the concave regions. The second transparent conductors 22 are respectively formed by the 214, and the refractive index of the second transparent conductors 22 is different from the refractive index of the first transparent conductors 21. Thereby, the interface between the refraction and the reflection of the light in the transparent conductive layer 2 can be increased, and the refraction and reflection effect of the light in the transparent conductive layer 2 can be improved, so that the light can be emitted outward toward the substrate 1. Effectively improve light extraction efficiency.

Further, in the experimental examples 1 to 4, the tables of the experimental examples 3 and 4 were again used. It is the best. This is because the proportion of the concave regions 214 formed at the light incident surface 212 of the experimental examples 3 and 4 is relatively high, and the interface between the refraction and the reflection of the light in the transparent conductive layer 2 can be increased, thereby improving the light refraction effect and The reflection effect effectively increases the light extraction efficiency.

However, the above is only an embodiment of the present invention, when The scope of the present invention is not limited thereto, that is, the simple equivalent changes and modifications made by the present invention in the scope of the invention and the patent specification are still within the scope of the invention.

1‧‧‧Substrate

2‧‧‧Transparent conductive layer

21‧‧‧First transparent conductor

211‧‧‧Glossy

212‧‧‧Into the glossy surface

213‧‧‧ base area

214‧‧‧ recessed area

22‧‧‧Second transparent conductor

221‧‧‧ arc convex

222‧‧‧flat surface

3‧‧‧Organic lighting unit

4‧‧‧Electrode

D‧‧‧ Depth of depression

Claims (10)

An organic light emitting diode device comprising: a substrate; and a transparent conductive layer disposed adjacent to the substrate, an organic light emitting unit and an electrode; the transparent conductive layer comprising: a first transparent conductive body a light-emitting surface facing the substrate, and a light-incident surface facing the organic light-emitting unit; the light-incident surface has a base region, and a plurality of concave portions which are separated from each other and are respectively recessed from the base region toward the light-emitting surface And a plurality of second transparent conductors respectively disposed in the recessed regions, wherein the second transparent conductors have a refractive index different from a refractive index of the first transparent conductors. The organic light-emitting diode device of claim 1, wherein the recessed regions have a recess depth of 50 to 200 nm. The organic light-emitting diode device according to claim 1 or 2, wherein an area of the concave regions projected onto the light-emitting surface accounts for 7 to 30% of an area projected onto the light-emitting surface by the light-incident surface. The organic light emitting diode device of claim 3, wherein the base region of the light incident surface is flat; each of the second transparent conductive bodies has an arc convex surface that fits the corresponding concave region, and one cut a flat surface of the base region; the organic light emitting unit is disposed on the base region and the flat surfaces. The organic light emitting diode device of claim 3, wherein the material of the first transparent conductor is indium tin oxide; the material of the second transparent conductor is aluminum zinc oxide, indium zinc oxide or manganese manganese oxide. . A method of fabricating an organic light emitting diode device, comprising: forming a first transparent conductive body on a substrate, the first transparent conductive body having a light emitting surface facing the substrate, and a light incident surface facing away from the substrate Etching the light incident surface of the first transparent conductor such that the light incident surface forms a base region, and a plurality of recessed regions spaced apart from each other and recessed from the base region toward the light exiting surface; in the recessed regions Forming a plurality of second transparent conductors different in refractive index from the first transparent conductor; forming an organic light emitting unit on the first transparent conductor and the second transparent conductor; and forming an organic light emitting unit on the second transparent conductor An electrode is formed. The method of manufacturing the organic light emitting diode device of claim 6, wherein after etching the light incident surface of the first transparent conductive body, each of the concave regions defines a groove; and then the light incident surface Forming a transparent conductive material such that the transparent conductive material simultaneously abuts the base region and protrudes into the recesses to abut the recessed regions; and then removes the portion of the transparent conductive material that abuts the base region The second transparent conductors are formed. The method of manufacturing an organic light-emitting diode device according to claim 7, wherein the second transparent conductor is cut to the base region when the portion of the transparent conductive material that abuts the base region is removed. The method of manufacturing an organic light emitting diode device according to claim 6, wherein the light incident surface of the first transparent conductive body is etched to form the concave portions. In the case of the region, etching is performed to the recessed regions to have a recess depth of 50 to 200 nm. The method of manufacturing an organic light-emitting diode device according to claim 6, wherein an area of the concave regions projected onto the light-emitting surface accounts for 7 to 30% of an area projected onto the light-emitting surface by the light-incident surface.