CN111146256B

CN111146256B - High-stability organic light-emitting diode

Info

Publication number: CN111146256B
Application number: CN201911286327.9A
Authority: CN
Inventors: 鲁天星; 吴海燕; 朱映光; 张国辉; 胡永岚; 李栋栋
Original assignee: Guan Yeolight Technology Co Ltd
Current assignee: Guan Yeolight Technology Co Ltd
Priority date: 2019-12-13
Filing date: 2019-12-13
Publication date: 2023-08-22
Anticipated expiration: 2039-12-13
Also published as: CN111146256A

Abstract

The invention discloses a high-stability organic light-emitting diode, which sequentially comprises a first electrode layer, an organic functional layer and a second electrode layer from bottom to top, wherein the organic functional layer and the second electrode layer form an organic film layer, pixel limiting layers distributed in an array are arranged between the first electrode layer and the organic functional layer, and the pixel limiting layers are higher than the upper plane of the organic film layer between two adjacent pixel limiting layers; the outer side surface of the pixel limiting layer forms a lap joint area and a disconnection area, and an organic film layer positioned above the pixel limiting layer at the lap joint area forms lap joint with an organic film layer positioned between the two pixel limiting layers; the organic film layer located above the pixel defining layer at the break area is broken from the organic film layer located between the two pixel defining layers. Harmful gas generated in the organic light emitting diode can be directly discharged through the disconnection area around the pixel limiting layer without permeation through the organic functional layer and the second electrode layer, so that the service life and the stability are greatly improved.

Description

High-stability organic light-emitting diode

Technical Field

The invention relates to the technical field of organic semiconductor illumination, in particular to a high-stability organic light-emitting diode.

Background

A Pixel Defining Layer (PDL) is an organic light emitting diode for defining a light emitting region and insulating function, and generally, a photosensitive polyimide (PSPI) can fulfill the above requirements. However, in severe environments, such as high temperature, high humidity, and sunlight, PSPI typically releases impurities or gases, which are detrimental to the organic light emitting diode and may lead to a reduced lifetime. The main reason is that PSPI contains some pi conjugated functional groups, electrons of these functional groups can be excited under the condition of light, electricity or heat, and chemical reaction occurs between the functional groups, so that some impurities or gases are released, and permeate out directly through the organic functional layer and the second electrode layer, so that pixels shrink, and the reliability of the organic light emitting diode is affected, as shown in fig. 1 and 2.

Disclosure of Invention

In order to solve the adverse effect of photosensitive polyimide (PSPI) on the reliability of an OLED in severe environments such as high temperature, high humidity, ambient light and the like in the prior art, the invention designs the screen structure so that the gas released by PDL can be released, the erosion of the gas release on the OLED is reduced, and the reliability of the OLED is improved.

The invention adopts the following technical scheme:

the organic light-emitting diode with high stability comprises a first electrode layer, an organic functional layer and a second electrode layer from bottom to top in sequence, wherein the organic functional layer and the second electrode layer form an organic film layer; the outer side surface of the pixel limiting layer forms a lap joint area and a disconnection area, and an organic film layer positioned above the pixel limiting layer at the lap joint area forms lap joint with an organic film layer positioned between the two pixel limiting layers; an organic film layer located above the pixel defining layers at the break area is broken from an organic film layer located between the two pixel defining layers.

The outer side surface of the pixel limiting layer corresponding to the position of the breaking area is gradually contracted inwards in the direction approaching to the first electrode layer, and a ventilation gap is formed between the outer side surface of the pixel limiting layer and the organic film layer outside the pixel limiting layer.

Preferably, an included angle of 90-120 degrees is formed between the outer side surface of the pixel limiting layer corresponding to the position of the disconnection region and the first electrode layer.

The outer side surface of the pixel limiting layer corresponding to the lap joint area is gradually outwards expanded in the direction approaching the first electrode layer.

Preferably, an included angle of 0-60 degrees is formed between the outer side surface of the pixel limiting layer corresponding to the position of the overlap region and the first electrode layer.

And forming a breaking area with a right angle or obtuse angle dip angle and a lapping area with an acute angle dip angle on the outer side surface of the pixel defining layer through a photoetching process.

The height h of the pixel limiting layer is more than or equal to 1um, and the pixel limiting layer is 0.1-5 mu m higher than the organic film layer between two adjacent pixel limiting layers.

The cross section of the pixel limiting layer is of a polygonal structure, and the lap joint area is arranged at the edge position or the corner position of the pixel limiting layer.

The overlap length of the overlap region formed at the edge position above the pixel defining layer is 10% or more of the length of the break region (20).

The pixel defining layer is one of phenolic resin, siloxane polymer, acrylic resin, epoxy resin, silicon oxide and silicon nitride.

An auxiliary electrode layer is further arranged between the first electrode layer and a corresponding region right below the pixel limiting layer.

The technical scheme of the invention has the following advantages:

A. the organic light-emitting diode is internally provided with the pixel limiting layers distributed in a matrix, the heights of the pixel limiting layers are higher than the upper surface of the second electrode between two adjacent pixel limiting layers, meanwhile, the organic functional layers and the second electrode layers above the pixel limiting layers are electrically conducted up and down through the lap joint areas and the organic functional layers and the second electrode layers with lower heights outside the pixel limiting layers, and harmful gases such as water vapor, acid gas, outgas and the like generated in the organic light-emitting diode can be directly discharged through the disconnection areas around the pixel limiting layers, and the service life and the stability can be improved without permeation through the organic functional layers and the second electrode layers.

B. The invention adopts the pixel limiting layer with the cross section gradually shrinking inwards from top to bottom, so that a gap for guiding out harmful gas is formed between the film layer formed by the organic functional layer above the pixel limiting layer and the second electrode layer and the film layer at other positions, and the pixel limiting layers with different dip angles can be set according to specific conditions, thereby greatly improving the guiding-out efficiency of the harmful gas.

C. The invention processes the outer side surface of the pixel limiting layer through a photoetching process, for example, a first wet etching process is used for forming a break area on the pixel limiting layer, the outer side surface of the pixel limiting layer corresponding to the break area and the first electrode layer form an obtuse angle structure which is right-angled or contracted from top to bottom, and on the basis, the same photoresist or different photoresist is used for forming a lap joint area with lap joint structure patterns through a second wet etching process, namely, the inclination angle of the formed pixel limiting layer and the first electrode layer is an acute angle, and the membrane layer is separated through arranging a continuous organic membrane layer and arranging different inclination angle structures of the pixel limiting layer, so that the defect that the release of water vapor is realized mainly through separating metal cathode aluminum in the prior art is overcome, and the invention has important significance for prolonging the service life and improving the stability of the organic diode.

Drawings

In order to more clearly illustrate the embodiments of the present invention, the drawings that are required for the embodiments will be briefly described, and it will be apparent that the drawings in the following description are some embodiments of the present invention and that other drawings may be obtained according to the drawings without inventive effort for a person skilled in the art.

Fig. 1 is a plan view structural diagram of a related art organic light emitting diode;

FIG. 2 is a schematic view of section A-A of FIG. 1;

FIG. 3 is a plan view of an OLED according to the present invention;

FIG. 4 is a schematic view in section B-B of FIG. 3;

FIG. 5 is a schematic view in section C-C of FIG. 3;

FIG. 6 is a schematic view of section D-D of FIG. 3;

fig. 7a, 7b, and 7c are enlarged views of the E portion of the three structures of fig. 3;

FIG. 8 is a schematic view of a lapping film layer formed over a pixel defining layer according to the present invention;

FIG. 9 is a schematic plan view of a photolithography process according to the present invention;

FIG. 10a is a first schematic view of the E-E cross-section of FIG. 9;

FIG. 10b is a second schematic view of the E-E cross-section of FIG. 9;

the figures are identified as follows:

1-a first electrode layer; 2-an organic functional layer; 3-a second electrode layer; a 4-pixel defining layer; 5-an auxiliary electrode layer; 6-a substrate; 7-photoresist A; 8-photoresist B.

10-lap zone; 20-break zone.

Detailed Description

The following description of the embodiments of the present invention will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are directions or positional relationships based on the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements to be referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; the mechanical connection and the electrical connection can be adopted; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.

As shown in fig. 3 and 8, the high-stability organic light-emitting diode provided by the invention sequentially comprises a first electrode layer 1, an organic functional layer 2 and a second electrode layer 3 from bottom to top, wherein pixel limiting layers 4 distributed in an array are arranged between the first electrode layer 1 and the organic functional layer 2, the organic functional layer and the second electrode layer form an organic film layer of the diode, and the pixel limiting layers 4 are higher than the upper plane of the second electrode layer 3 between two adjacent pixel limiting layers 4, as shown in fig. 4; a lap joint region 10 and a break-off region 20 are formed on the outer side surface of the pixel defining layer 4, and the organic functional layer and the second electrode layer at the position of the lap joint region 10 are respectively lap-jointed with the organic functional layer 2 and the second electrode layer 3 on the outer side thereof, as shown in fig. 5. The organic functional layer and the second electrode layer above the corresponding pixel defining layer at the break area 20 form corresponding faults with the organic functional layer and the second electrode layer outside thereof, respectively, as shown in fig. 4 and 6, since the pixel defining layer 4 is higher than the second electrode layer and the organic functional layer at the periphery thereof, the pixel defining layer is exposed at the break area position, forming a channel for the harmful gas to be directly discharged therefrom. In normal operation, the generated harmful gases (including moisture) will be directly discharged through the pixel defining layer at a position higher than the peripheral second electrode layer thereof, as shown in fig. 6. Under the environments of high temperature, high humidity, sunlight and the like, water vapor and harmful gas are released in time, and pixels cannot shrink, so that the reliability of the whole OLED is improved, and the application environment is wider.

The pixel defining layer can be made of resin materials, such as phenolic resin, siloxane polymer, acrylic resin and epoxy resin, and can also be made of inorganic silicon oxide and silicon nitride, so that the reliability of the OLED screen body can be improved. The invention can improve the service life and the stability of the organic light-emitting diode by introducing the pixel limiting layer into the organic light-emitting diode.

In order to improve the conductivity of the first electrode layer, the present invention further includes an auxiliary electrode layer 5 between the first electrode layer 1 and a region corresponding to the region immediately below each pixel defining layer 4, and the pixel defining layer is superimposed on the auxiliary electrode layer.

As shown in fig. 4, the outer side surface of the pixel defining layer 4 corresponding to the position of the breaking area 20 is gradually shrunk inwards from top to bottom, so as to break the organic film layer (including the organic functional layer and the second electrode layer) on the pixel defining layer, that is, the organic film layer on the pixel defining layer is broken in the breaking area (that is, the non-overlapping area), and a ventilation gap is generated between the outer side of the pixel defining layer 4 and the peripheral organic film layer, so that the outgas is released on the organic film layer, rather than permeated along the organic film layer to cause the pixel to shrink.

In the present invention, preferably, in the break-off region, the pixel defining layer has an inverted structure, that is, the photoresist forms an inclination angle α of a right angle or an obtuse angle on the substrate, and the inclination angle α is preferably used to be 90 ° to 120 °.

As shown in fig. 5, a lap joint structure is formed in the lap joint area, so that the organic film layer on the pixel limiting layer is continuous, and the upper and lower conduction of the organic film layer of the OLED is realized; the outer side surface of the pixel limiting layer 4 corresponding to the position of the lap joint area 10 is gradually outwards expanded from top to bottom. Preferably, in the overlap region, the pixel defining layer has a positive trapezoid structure compared to the substrate, i.e. the photoresist forms an acute angle α of less than 90 ° on the substrate, preferably with α+.60°.

The tilt angle formed for the landing and break regions may be formed by a photolithographic process, as shown in fig. 9. For example, the photoresist is manufactured by a two-time wet etching process, and the structure pattern (or called non-lap joint structure) of the break area is formed by a first-time wet etching process, namely, the inclination angle of the formed photoresist is a right angle or an obtuse angle, and the structure pattern of the lap joint area is formed by the same photoresist or different photoresists on the basis through a second-time wet etching process, namely, the inclination angle formed by the photoresist is an acute angle. Because of the maturation process, no further description is given here. Considering the interface problem of the landing and break areas, since the photoresist generally has leveling property, the landing and break areas may be formed to have the same height as shown in fig. 10 a; of course, as long as the continuity of the subsequent organic film layer of the overlap region is not affected, different heights may be formed at the interface of the overlap region and the break region, as shown in fig. 10b, for example, a gentle slope, a slope angle of an acute angle (< 90 °).

The photoresist A7 used in the lap joint area can be positive photoresist, such as phenolic resin photoresist; the photoresist B8 used in the non-lap joint region can be negative photoresist, such as PMMA photoresist. Of course, other types of materials may be used, such as silicon oxide, silicon nitride, and the like. The photolithography process may be wet or dry. Because the photolithography process is a mature solution in the industry, it is not described in detail herein. The height h of the pixel defining layer 4 used in the present invention is 1um or more, as h=2μm in fig. 4, and the height of the pixel defining layer 4 is 0.1-1.5 μm, preferably 0.5 μm, higher than the second electrode layer outside thereof.

As shown in fig. 7a, 7b and 7c, the cross section of the pixel defining layer 4 is preferably a rectangular structure, but may also have other structural shapes, such as a square, trapezoid, or other polygonal structure, and when the cross section is a square structure, the overlap region 10 is disposed at a middle position or four corner positions of four outer sides of the pixel defining layer 4, and the overlap region may be in a concave or convex structure, so that the overlap between the pixel defining layer and the peripheral organic film layer is achieved through the overlap region.

The overlap length of the overlap region 10 formed at the edge position above the pixel defining layer 4 is 10% or more of the length of the break region 20.

Comparative examples:

the same OLED device structure is used.

Traditional OLED PSPI (PDL) lap joint structure, PSPI dip angle is 30 degrees;

by adopting the structure, PSPI is adopted, the angle formed by the pixel limiting layers at the fault area is 120 degrees, and the overlap angle formed by the pixel limiting layers at the overlap area is 30 degrees.

The luminous aging experiment is carried out in a high-temperature high-humidity environment, the OLED is lightened by adopting a constant-current power supply, and the OLED is lightenedThe degree is 1000cd/m ² The pixel shrinkage is observed for 1000h as follows:

	traditional PDL structure	The invention is that
			Pixel shrinkage condition	10um	Is not contracted

As can be seen from the table, after the lap joint structure is adopted, the problem of shrinkage of the screen pixels does not occur, the ventilation effect is good, and the comparison service life is as follows: conventional service life of Ni90=500 h, and the service life of Ni90=800 h is prolonged by 300h.

According to the invention, the pixel limiting layer with the cross section gradually shrinking inwards from top to bottom is adopted at the position of the disconnection area, so that a gap for guiding out harmful gas is formed between the organic functional layer above the pixel limiting layer and the film layer formed by the second electrode layer and the organic film layer at the outer side position of the pixel limiting layer, moisture or toxic gas is prevented from remaining, the pixel limiting layers with different inclined angles can be set according to specific conditions, the discharge efficiency of the harmful gas is greatly improved, and the technical problem of pixel shrinkage caused by the release of water vapor and other gases by the insulating layer when the OLED screen body works is solved.

It should be apparent that the above embodiments are merely examples for clarity of illustration and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary or exhaustive of all embodiments. While still being apparent from variations or modifications that may be made by those skilled in the art are within the scope of the present invention.

Claims

1. The high-stability organic light-emitting diode comprises a first electrode layer (1), an organic functional layer (2) and a second electrode layer (3) from bottom to top in sequence, wherein the organic functional layer (2) and the second electrode layer (3) form an organic film layer, and the high-stability organic light-emitting diode is characterized in that pixel limiting layers (4) distributed in an array are arranged between the first electrode layer (1) and the organic functional layer (2), and the pixel limiting layers (4) are higher than the upper plane of the organic film layer between two adjacent pixel limiting layers (4); an overlap region (10) and a break region (20) are formed on the outer side surface of the pixel defining layer (4), an overlap is formed between an organic functional layer located above the pixel defining layer and an organic functional layer located between the two pixel defining layers at the overlap region (10), and an overlap is formed between a second electrode layer located above the pixel defining layer and a second electrode layer located between the two pixel defining layers at the overlap region (10); an organic film layer located above the pixel defining layers at the break-off region (20) is broken off from an organic film layer located between the two pixel defining layers;

the outer side surface of the pixel limiting layer (4) corresponding to the position of the breaking area (20) gradually contracts inwards in the direction approaching the first electrode layer, and a ventilation gap is formed between the outer side surface of the pixel limiting layer (4) and the organic film layer outside the pixel limiting layer.

2. The high-stability organic light-emitting diode according to claim 1, wherein an included angle of 90 ° to 120 ° is formed between the outer side surface of the pixel defining layer (4) corresponding to the position of the breaking region (20) and the first electrode layer (1).

3. The high-stability organic light emitting diode according to claim 1, wherein the outer side surface of the pixel defining layer (4) corresponding to the position of the overlap region (10) is gradually flared in a direction approaching the first electrode layer.

4. A high stability organic light emitting diode according to claim 3, wherein the outer side of the pixel defining layer (4) corresponding to the position of the overlap region (10) forms an angle of 0-60 ° with the first electrode layer (1).

5. The high-stability organic light emitting diode according to any one of claims 1 to 4, wherein the break-off region (20) having a right or obtuse angle inclination and the landing region (10) having an acute angle inclination are formed on the outer side of the pixel defining layer by a photolithography process.

6. The high-stability organic light emitting diode according to claim 1, wherein the height h of the pixel defining layer (4) is not less than 1 μm, and the pixel defining layer (4) is higher than the organic film layer between two adjacent pixel defining layers by 0.1 μm to 5 μm.

7. The high-stability organic light emitting diode according to claim 6, wherein the cross section of the pixel defining layer (4) is a polygonal structure, and the overlap region (10) is disposed at an edge position or a corner position of the pixel defining layer (4).

8. The high-stability organic light emitting diode according to claim 7, wherein a lap joint length of the lap joint region (10) formed at an edge position above the pixel defining layer (4) is 10% or more of a length of the break-off region (20).

9. The high-stability organic light emitting diode according to claim 1, wherein the pixel defining layer (4) is one of a phenolic resin, a siloxane polymer, an acryl resin, an epoxy resin, silicon oxide and silicon nitride.

10. The high-stability organic light emitting diode according to claim 1, wherein an auxiliary electrode layer (5) is further provided between the first electrode layer (1) and a corresponding region directly under the pixel defining layer (4).