CN102024912B - Light-emitting unit of electroluminescence device and manufacturing method thereof - Google Patents

Abstract

A light emitting unit of an electroluminescent device includes a power line, a first electrode layer, a light emitting layer, and a second electrode layer. The power line is located on the substrate. The first electrode layer is located on the substrate and electrically connected with the power line, wherein the oxygen content of the top of the first electrode layer is higher than that of the bottom of the first electrode layer. The light emitting layer is positioned on the first electrode layer. The second electrode layer is located on the light emitting layer. The invention can increase the whole aperture ratio of the electroluminescent device.

Description

Light-emitting unit of electroluminescence device and manufacturing method thereof

technical field

The invention relates to a light-emitting unit of an electroluminescent device and a manufacturing method thereof, in particular to a light-emitting unit of an organic electroluminescent device and a manufacturing method thereof.

Background technique

Organic electroluminescent devices have excellent characteristics such as thinness, self-luminescence, low power consumption, no need for backlight, no viewing angle limitation, and high response rate. They have been regarded as the rising stars of flat-panel displays. In addition, passive organic light-emitting devices can form an array structure on a thin, flexible substrate, so they are also very suitable for lighting applications. It is generally estimated that the luminous efficiency of organic light-emitting devices will increase to more than 100Lm/W, and the color rendering When the luminance is higher than 80, it has the opportunity to replace the general lighting source, so the organic light-emitting device will play a very important role in the lighting equipment.

In a large-area organic electroluminescent device, if a single foreign object exists, it may cause a short circuit in the entire organic light-emitting device. Therefore, generally, a large-area organic light-emitting device is divided into a plurality of light-emitting units of small-area blocks, and a resistor line is connected to each light-emitting unit. The resistance wire can limit the amount of current passing through the light-emitting unit when the light-emitting unit is short-circuited so that other light-emitting units will not be affected. However, the arrangement of the above resistance wires will reduce the overall aperture ratio of the organic light emitting device.

Contents of the invention

The invention provides a light-emitting unit of an electroluminescent device and a manufacturing method thereof, which can solve the known problem that arranging resistance wires in an organic electroluminescent device will reduce the overall aperture ratio of the organic light-emitting device.

The invention provides a light-emitting unit of an electroluminescence device, which includes a power line, a first electrode layer, a light-emitting layer, and a second electrode layer. The power wires are located on the base board. The first electrode layer is located on the substrate, and the first electrode layer is electrically connected to the power line, wherein the oxygen content of the top of the first electrode layer is higher than the oxygen content of the bottom of the first electrode layer. The light emitting layer is located on the first electrode layer. The second electrode layer is located on the light emitting layer.

The invention provides a method for manufacturing a light emitting unit of an electroluminescence device. The method includes forming power lines on a substrate. Forming the first electrode layer on the substrate, wherein the first electrode layer is electrically connected to the power line, and forming the first electrode layer includes performing a deposition process, the deposition process includes feeding oxygen, and the amount of the oxygen gas that is fed varies with the increases with the time of the deposition process. A light emitting layer is formed on the first electrode layer. A second electrode layer is formed on the light emitting layer.

Based on the above, since the oxygen content of the top of the first electrode layer of the light-emitting unit of the electroluminescent device of the present invention is higher than the oxygen content of the bottom of the first electrode layer, the place where the first electrode layer contacts the light-emitting layer have a larger resistance value. In this way, when a short-circuit occurs in a certain light-emitting unit, the current through the light-emitting unit can be limited because of the high resistance value of the top of the first electrode layer, so that other light-emitting units will not be affected. In other words, the present invention uses the first electrode layer with a higher oxygen content at the top to omit the traditional resistance lines, thereby increasing the overall aperture ratio of the electroluminescent device.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail together with the accompanying drawings.

Description of drawings

FIG. 1 is a schematic partial top view of an electroluminescent device according to an embodiment of the present invention.

Fig. 2 is a schematic cross-sectional view of Fig. 1 along the section line A-A'.

FIG. 3 is a schematic partial top view of an electroluminescent device according to another embodiment of the present invention.

Fig. 4 is a schematic cross-sectional view of Fig. 3 along the section line B-B'.

Wherein, the reference signs are explained as follows:

100: Substrate

108: insulation layer

106: first electrode layer

106a: Bottom

106b: top

110: organic light-emitting layer

112: Second electrode layer

U: light emitting unit

PL: power cord

Detailed ways

FIG. 1 is a schematic partial top view of an electroluminescent device according to an embodiment of the present invention. Fig. 2 is a schematic cross-sectional view of Fig. 1 along the section line A-A'. In order to illustrate this embodiment clearly, FIG. 1 shows some light emitting units of an electroluminescent device. Generally speaking, an electroluminescent device is composed of a plurality of light emitting units U. In addition, FIG. 1 only shows the power line and the first electrode layer of a part of the light-emitting unit. In fact, the film layers of the light-emitting unit of the electroluminescent device are shown in FIG. 2 .

Please refer to FIG. 1 and FIG. 2 , the manufacturing method of the electroluminescence device of this embodiment firstly provides a substrate 100 . The material of the substrate 100 can be glass, quartz, organic polymer, plastic, flexible plastic or opaque/reflective material and the like. Next, a power line PL is formed on the substrate 100 . The method of forming the power lines PL is, for example, to first perform a deposition process to form a conductive layer (not shown) on the substrate 100 , and then pattern the conductive layer by photolithography and etching processes to form a plurality of power lines. The power line PL mainly provides the power required by each light-emitting unit U, so the power line PL is electrically connected to the power supply device when it extends to the edge of the substrate 100 . Based on the consideration of electrical conductivity, the power line PL is generally made of metal materials, such as copper, aluminum, silver, gold, titanium, molybdenum, tungsten, chromium and alloys or laminates thereof. However, the present invention is not limited thereto. According to other embodiments, the power line PL can also use other conductive materials, such as alloys, nitrides of metal materials, oxides of metal materials, oxynitrides of metal materials, or other suitable materials), or metal materials and other stacked layers of conductive material.

Afterwards, a first electrode layer 106 is formed on the substrate 100 , wherein the first electrode layer 106 is electrically connected to the power line PL, and the first electrode layer 106 is, for example, an anode. In this embodiment, the first electrode layer 106 is directly connected to the power line PL. According to this embodiment, the formed edge of the first electrode layer 106 and the edge of the PL power line can be directly connected together, so that the first electrode layer 106 can be electrically connected with the PL power line. In addition, the first electrode layer 106 includes metal oxides, such as indium tin oxide, indium zinc oxide, aluminum tin oxide, aluminum zinc oxide, indium germanium zinc oxide, indium oxide, germanium oxide gallium oxide, zinc oxide (zinc oixde), tin oxide (tin oxide), molybdenum oxide (molybdenum oxide), vanadium oxide (vanadium oxide), antimony oxide (antimony oxide), bismuth oxide ( bismuth oxide), rhenium oxide, tantalum oxide, tungsten oxide, niobium oxide, nickel oxide or other suitable metal oxides, Or a stacked layer of at least two of the above.

In particular, the method for forming the first electrode layer 106 includes performing a deposition procedure, and the deposition procedure includes injecting oxygen gas, and the amount of the injected oxygen gas increases with the time of the deposition procedure. According to the present embodiment, the above-mentioned deposition procedure includes feeding inert gas, and the flow ratio of oxygen to inert gas increases from 1:10 to 1:1 with the time of the deposition procedure. The aforementioned inert gas includes argon, helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn) or combinations thereof.

The oxygen content of the top 106b of the first electrode layer 106 formed by the above deposition process is higher than that of the bottom 106a. Preferably, the oxygen content in the first electrode layer 106 gradually increases from the bottom 106a to the top 106b. That is, the oxygen content in the first electrode layer 106 gradually increases from the bottom 106a to the top 106b. The present invention is not limited in what kind of gradient form the oxygen content in the first electrode layer 106 increases from the bottom 106 a to the top 106 b. In other words, the oxygen content in the first electrode layer 106 can increase from the bottom 106 a to the top 106 b in a stepwise, linear or curved manner. According to this embodiment, the oxygen content of the first electrode layer 106 varies from 50 mol% to 70 mol% from the bottom 106a to the top 106b.

Since the oxygen content in the first electrode layer 106 gradually increases from the bottom 106a to the top 106b, the resistance of the first electrode layer 106 gradually increases from the bottom 106a to the top 106b. In this embodiment, the resistivity of the first electrode layer 106 varies from 1.5×10 ⁻⁴ Ω·cm to 5000 Ω·cm from the bottom 106 a to the top 106 b.

It is worth mentioning that in the manufacturing process of the traditional electroluminescence device, after the first electrode layer is formed on the substrate, the surface of the first electrode layer will be treated with ultraviolet light-ozone, so that the first electrode layer Have an appropriate work function. However, in this embodiment, because the top of the first electrode layer 106 has a relatively high oxygen content, the first electrode layer 106 already possesses proper properties of a work function, so this embodiment is formed after forming the first electrode layer 106. After an electrode layer 106, the above-mentioned UV-ozone treatment procedure is not required. In addition, in general, metal oxides with high oxygen content have higher penetration rates. Since the top of the first electrode layer 106 in this embodiment has a higher oxygen content, the first electrode layer 106 in this embodiment has a higher transmittance than ordinary metal oxides.

After the first electrode layer 106 is formed, the light emitting layer 110 is then formed on the first electrode layer 106 . In this embodiment, in order to locate the light emitting layer 110 of each light emitting unit U at a specific position, before forming the light emitting layer 110 , an insulating layer 108 is formed on the first electrode layer 106 first. The insulating layer 108 exposes the first electrode layer 106 in each light emitting unit U. Afterwards, the light emitting layer 110 can be formed on the exposed surface of the first electrode layer 108 by spraying. However, the present invention does not limit that the insulating layer 108 must be formed. In other embodiments, the fabrication of the insulating layer 108 may also be omitted, and the light-emitting layer 110 may be formed by a precise inkjet process or other fabrication methods.

According to an embodiment of the present invention, the light-emitting layer 110 may be a single-layer light-emitting layer or a combination of a light-emitting layer plus an electron transport layer, an electron injection layer, a hole transport layer, and a hole injection layer. The light-emitting layer is, for example, a white light-emitting material layer or a light-emitting material layer of other specific colors (such as red, green, blue, etc.). In addition, at least one of the electron transport layer, electron injection layer, hole transport layer and hole injection layer can be selected to match with the light-emitting layer to form a stacked layer of two, three, four or five layers, thereby enhancing The luminous efficiency of the light emitting layer 110. The detailed material and structure of the light-emitting layer 110 are well known to those skilled in the art, so details will not be repeated here.

It is worth mentioning that since the oxygen content in the first electrode layer 106 gradually increases from the bottom 106 a to the top 106 b, and the light emitting layer 110 is formed on the first electrode layer 106 . Therefore, the oxygen content of the first electrode layer 106 near the light emitting layer 110 is greater than the oxygen content of the first electrode layer 106 near the substrate 100 .

Next, the second electrode layer 112 is formed on the light emitting layer 110 . In this embodiment, the second electrode layer 112 may be a strip-shaped conductive layer, so the second electrode layer 112 of each light emitting unit U is arranged approximately perpendicular to the power line PL. Similarly, the second electrode layer 112 is, for example, a transparent electrode layer, such as a metal oxide layer, such as indium tin oxide, indium zinc oxide, aluminum tin oxide, aluminum zinc oxide, indium germanium zinc oxide , or other suitable metal oxides, or a stacked layer of at least two of the above; or a thin metal layer or thin metal stack with high light transmittance. Certainly, according to other embodiments, the second electrode layer 112 may be an opaque electrode layer.

It is worth mentioning that if both the first electrode layer 106 and the second electrode layer 112 are transparent electrode layers, then the formed electroluminescent device is a double-sided light emitting device. If the first electrode layer 106 is a transparent electrode layer and the second electrode layer 112 is an opaque electrode layer, then the formed electroluminescent device is a bottom emission type light emitting device. If the first electrode layer 106 is an opaque electrode layer and the second electrode layer 112 is a transparent electrode layer, then the formed electroluminescent device is a top emission type light emitting device.

The light emitting unit U of the electroluminescent device formed according to the above method includes a power line PL, a first electrode layer 106 , a light emitting layer 110 and a second electrode layer 112 . The power line PL is located on the substrate 100 . The first electrode layer 106 is located on the substrate 100, and the first electrode layer 106 is electrically connected to the power line PL, wherein the oxygen content of the top 106b of the first electrode layer 106 is higher than the oxygen content of the bottom 106a of the first electrode layer 106 quantity. The light emitting layer 110 is located on the first electrode layer 106 . The second electrode layer 112 is located on the light emitting layer 110 .

According to an embodiment of the present invention, the oxygen content in the first electrode layer 106 gradually increases from the bottom 106 a to the top 106 b. The present invention does not limit the oxygen content in the first electrode layer 106 in which kind of gradual increase from the bottom 106 a to the top 106 b. In other words, the oxygen content in the first electrode layer 106 can increase from the bottom 106 a to the top 106 b in a stepwise, linear or curved manner. According to this embodiment, the oxygen content of the first electrode layer 106 varies from 50 mol% to 70 mol% from the bottom 106a to the top 106b. Since the oxygen content in the first electrode layer 106 gradually increases from the bottom 106a to the top 106b, the resistivity of the first electrode layer 106 gradually increases from the bottom 106a to the top 106b. In this embodiment, the resistivity of the first electrode layer 106 varies from 1.5×10 ⁻⁴ Ω·cm to 5000 Ω·cm from the bottom 106 a to the top 106 b.

As mentioned above, since the oxygen content of the top 106 b of the first electrode layer 106 of the light emitting unit U of the electroluminescent device of this embodiment is higher than the oxygen content of the bottom 106 a of the first electrode layer 106 . In other words, the first electrode layer 106 closer to the light emitting layer 110 has a larger resistivity. Therefore, the first electrode layer 106 still has a sufficiently low resistivity in the lateral direction, and the high oxygen content on the top 106b of the first electrode layer 106 is equivalent to connecting the light emitting unit U with a resistor in series. Therefore, when a light-emitting unit U is short-circuited, the high resistance at the top of the first electrode layer 106 can limit the amount of current passing through the light-emitting unit, so that other light-emitting units will not be affected. In other words, this embodiment can omit the traditional resistance wires to increase the overall aperture ratio of the electroluminescent device.

FIG. 3 is a schematic partial top view of an electroluminescent device according to another embodiment of the present invention. Fig. 4 is a schematic cross-sectional view of Fig. 3 along the section line B-B'. The embodiment in FIG. 3 ( FIG. 4 ) is similar to the embodiment in FIG. 1 ( FIG. 2 ), so the same elements as those in FIG. 1 ( FIG. 2 ) are denoted by the same symbols and will not be repeated here. The embodiment of FIG. 3 ( FIG. 4 ) is different from the embodiment of FIG. 1 ( FIG. 2 ) in that the edge of the first electrode layer 106 overlaps the edge of the power line PL. In this embodiment, as shown in FIG. 4 , the first electrode layer 106 directly covers the power line PL, so that the first electrode layer 106 is electrically connected to the power line PL.

Similarly, in this embodiment, the oxygen content in the first electrode layer 106 gradually increases from the bottom 106a to the top 106b. The oxygen content in the first electrode layer 106 can increase from the bottom 106 a to the top 106 b in a stepwise, linear or curved manner. According to this embodiment, the oxygen content of the first electrode layer 106 varies from 50 mol% to 70 mol% from the bottom 106a to the top 106b. Since the oxygen content in the first electrode layer 106 gradually increases from the bottom 106a to the top 106b, the resistance of the first electrode layer 106 gradually increases from the bottom 106a to the top 106b. In this embodiment, the resistance value of the first electrode layer 106 varies from 1.5×10 ⁻⁴ Ω·cm to 5000 Ω·cm from the bottom 106 a to the top 106 b.

In summary, since the oxygen content at the top of the first electrode layer of the light-emitting unit of the electroluminescent device of the present invention is higher than the oxygen content at the bottom of the first electrode layer, the first electrode layer is in contact with the light-emitting layer. have higher resistivity. In this way, when a short-circuit occurs in a certain light-emitting unit of the electroluminescent device, because of the high resistivity of the top of the first electrode layer, the amount of current passing through the light-emitting unit can be limited, so that other light-emitting units can not be short-circuited. will be affected. In other words, the present invention uses the first electrode layer with a higher oxygen content at the top to omit the traditional resistance lines, thereby increasing the overall aperture ratio of the electroluminescent device.

In addition, because the top of the first electrode layer of the light-emitting unit of the electroluminescent device of the present invention has a relatively high oxygen content, the first electrode layer already possesses the properties of a suitable work function (work function), so the present invention can be used in After forming the first electrode layer, no conventional UV-ozone treatment procedure is required. Therefore, the present invention has the advantage of saving cost compared with the traditional electroluminescent device fabrication method.

In addition, metal oxides with high oxygen content generally have higher penetration rates. Since the top of the first electrode layer of the present invention has a higher oxygen content, the first electrode layer of the present invention has a higher transmittance than ordinary metal oxides.

In another embodiment of the present invention, the power line can also be electrically connected to the second electrode layer 112 instead of the first electrode layer 106 according to the needs of the designer, and the rest of the components are similar to the previous embodiment, so no Let me repeat. The second electrode layer 112 has a top and a bottom, wherein the distance between the top and the light-emitting layer is smaller than the distance between the bottom and the light-emitting layer, that is, in this embodiment, the second electrode layer 112 is placed close to the light-emitting layer The part of 110 is defined as the top, and the part of the second electrode layer 112 away from the light emitting layer 110 is defined as the bottom. The oxygen content at the top of the second electrode layer 112 is higher than the oxygen content at the bottom, wherein the oxygen content in the second electrode layer gradually increases from the bottom to the top, wherein the oxygen content in the second electrode layer The amount increases from the bottom to the top in steps, straight lines or curves, wherein the resistivity of the second electrode layer varies from 1.5×10 ^-4 Ω·cm to 5000 Ω·cm from the bottom to the top. In this embodiment, the second electrode layer 112 is, for example, an anode.

Although the present invention has been disclosed above with the embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection should be subject to the scope defined by the appended claims.

Claims (5)

1. the manufacturing approach of the luminescence unit of an el light emitting device comprises:

On a substrate, form a power line;

On this substrate, form one first electrode layer; This first electrode layer and this power line electrically connect; Wherein form this first electrode layer and comprise and carry out a deposition program that this deposition program comprises aerating oxygen, and the amount of the oxygen that is fed increases along with this deposition procedure time;

On this first electrode layer, form a luminescent layer; And

On this luminescent layer, form a second electrode lay;

Wherein should the deposition program also comprise feeding one inert gas, and the flow proportional of oxygen and this inert gas is along with this deposition procedure time increased to 1: 1 from 1: 10.

2. the manufacturing approach of the luminescence unit of el light emitting device as claimed in claim 1, wherein this inert gas comprises helium, neon, argon, krypton, xenon, radon or its combination.

3. the manufacturing approach of the luminescence unit of el light emitting device as claimed in claim 1, wherein the edge of the edge of this first electrode layer and this power line is overlapping or directly links together.

4. the manufacturing approach of the luminescence unit of el light emitting device as claimed in claim 1 wherein need not be carried out one ultraviolet light-ozone treatment program after forming this first electrode layer.

5. the manufacturing approach of the luminescence unit of el light emitting device as claimed in claim 1, wherein this first electrode layer comprises metal oxide.

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