Preparation method of organic electroluminescent panel and organic electroluminescent panel

Abstract

An isolation wall is formed on the side, away from a first electrode layer, of a pixel definition dam, and the first end face, close to the pixel definition layer, of the isolation wall is in the vertical projection of the second end face, away from the pixel definition layer, of the isolation wall in the pixel definition layer. Due to the shielding of the second end face of the isolation wall, the second electrode layer is not deposited on the side wall of the isolation wall, so that the second electrode layer is disconnected at the side wall of the isolation wall, and a conductive connection layer is formed subsequently to electrically connect the second electrode layer which is not continuous originally. The thickness of the conductive connection layer at the side wall of the isolation wall is smaller than the thickness of the conductive connection layer at other areas, when a certain organic light-emitting device is short-circuited, short-circuit current enables the conductive connection layer to be fused at the side wall of the isolation wall, so that the organic light-emitting device is isolated, large-area damage of the organic light-emitting panel is avoided, and the service life of the organic light-emitting panel is prolonged. The maintenance rate and the maintenance cost are reduced, and the user experience is improved.

Description

Technical Field

[0001] The present invention relates to organic electroluminescent technology, and in particular to an organic electroluminescent panel preparation method and an organic electroluminescent panel. Background Art

[0002] In an organic light-emitting diode (OLED), an electric field causes holes generated at the anode and electrons generated at the cathode to migrate, injecting into the hole-transport layer and electron-transport layer, respectively, before migrating to the light-emitting layer. When these two molecules meet in the light-emitting layer, they generate energy excitons, which in turn excite the luminescent molecules, ultimately producing visible light. OLEDs offer advantages such as high luminous efficiency, high brightness, long life, and environmental friendliness, making them widely used in display and lighting applications.

[0003] In large-area monochrome or white organic electroluminescent panels, all OLEDs share a common anode and cathode, meaning they utilize a full-surface structure. When a local short circuit occurs in the OLED panel, the short-circuit current concentrates at the short-circuit location and rapidly spreads. The heat generated then diffuses laterally through the anode or cathode, causing extensive damage to the OLED panel or even complete burnout. This increases the repair rate and costs, and results in a poor user experience. Summary of the Invention

[0004] The present invention provides an organic electroluminescent panel preparation method and an organic electroluminescent panel, which can avoid large-area damage of the organic electroluminescent panel caused by local short circuit, reduce the maintenance rate and maintenance cost, and improve user experience.

[0005] In a first aspect, the present invention provides a method for preparing an organic electroluminescent panel, comprising:

[0006] An organic electroluminescent panel precursor is prepared, the organic electroluminescent panel precursor comprising a carrier substrate, a first electrode layer, and a pixel definition layer, wherein the first electrode layer is disposed on one side of the carrier substrate, the pixel definition layer is disposed on a side of the first electrode layer away from the carrier substrate, and the pixel definition layer comprises a plurality of intersecting pixel definition dams, wherein the plurality of intersecting pixel definition dams form a plurality of openings;

[0007] forming an isolation layer on a side of the pixel definition layer away from the first electrode layer, the isolation layer comprising a plurality of intersecting isolation walls, the isolation walls being formed on the pixel definition dam, a first end surface of the isolation wall close to the pixel definition layer and a second end surface of the isolation wall away from the pixel definition layer being within a vertical projection of the pixel definition layer;

[0008] forming a light-emitting functional layer in the opening;

[0009] forming a second electrode layer on a side of the light-emitting functional layer away from the first electrode layer and on a side of the isolation wall away from the pixel definition layer, wherein the second electrode layer on the side of the isolation wall away from the pixel definition layer and the second electrode layer on the side of the light-emitting functional layer away from the first electrode layer are disconnected at a sidewall of the isolation wall;

[0010] forming a conductive connection layer on a side of the second electrode layer away from the first electrode layer, the conductive connection layer being used to connect the second electrode layer on a side of the isolation wall away from the pixel definition layer and the second electrode layer on a side of the light-emitting functional layer away from the first electrode layer, and a thickness of the conductive connection layer at a sidewall of the isolation wall being less than a thickness of the conductive connection layer in other areas;

[0011] An encapsulation layer is formed on a side of the conductive connection layer away from the second electrode layer to obtain an organic electroluminescent panel.

[0012] Optionally, preparing an organic electroluminescent panel precursor includes:

[0013] providing a carrier substrate;

[0014] forming a first electrode layer on one side of the carrier substrate;

[0015] A pixel definition layer is formed on a side of the first electrode layer away from the carrier substrate.

[0016] Optionally, the first electrode layer is divided into a light-emitting area and a non-light-emitting area, and the non-light-emitting area surrounds the light-emitting area. After the first electrode layer is formed on one side of the carrier substrate, the method further includes:

[0017] performing patterning on the first electrode layer to form a second electrode overlapping region in the non-luminescent region, wherein the second electrode overlapping region is insulated and isolated from the rest of the first electrode layer;

[0018] Accordingly, a pixel definition layer is formed on a side of the first electrode layer away from the carrier substrate, comprising:

[0019] A pixel definition layer is formed in the light emitting area on a side of the first electrode layer away from the carrier substrate.

[0020] Optionally, in the process of forming the isolation layer on the side of the pixel definition layer away from the first electrode layer, no isolation wall is formed on the pixel definition dam close to the non-luminous area.

[0021] Optionally, while a second electrode layer is formed on a side of the light-emitting functional layer away from the first electrode layer and a side of the isolation wall away from the pixel definition layer, a overlapping electrode is formed between the light-emitting area and the second electrode overlapping area, and the overlapping electrode is used to connect the second electrode layer and the second electrode overlapping area.

[0022] Optionally, after patterning the first electrode layer, the method further includes:

[0023] A metal grid is formed in the light emitting region on a side of the first electrode layer away from the carrier substrate.

[0024] Optionally, the cross-section of the isolation wall is an inverted trapezoid, and both bottom angles of the inverted trapezoid are less than 90°.

[0025] Optionally, forming a conductive connection layer on a side of the second electrode layer away from the first electrode layer includes:

[0026] The conductive connection layer is prepared by magnetron sputtering or atomic layer deposition. During the magnetron sputtering process, the target material and the substrate form an angle of 20°-60°, and the substrate rotates at a constant speed of 5rpm-15rpm. The substrate includes the organic electroluminescent panel precursor, the isolation layer, the light-emitting functional layer and the second electrode layer.

[0027] Optionally, after forming the encapsulation layer on the side of the conductive connection layer away from the second electrode layer, the method further includes:

[0028] A light extraction layer is formed on a side of the carrier substrate away from the first electrode layer.

[0029] In a second aspect, the present invention further provides an organic electroluminescent panel, which is prepared using the organic electroluminescent panel preparation method provided in the first aspect of the present invention, comprising:

[0030] a carrier substrate;

[0031] a first electrode layer, the first electrode layer being disposed on one side of the carrier substrate;

[0032] a pixel definition layer, the pixel definition layer being disposed on a side of the first electrode layer away from the carrier substrate, the pixel definition layer comprising a plurality of intersecting pixel definition dams, the plurality of intersecting pixel definition dams forming a plurality of openings;

[0033] a light-emitting functional layer, wherein the light-emitting functional layer is disposed in the opening;

[0034] an isolation layer, the isolation layer being disposed on a side of the pixel definition layer away from the first electrode layer, the isolation layer comprising a plurality of intersecting isolation walls, the isolation walls being formed on the pixel definition dam, a first end surface of the isolation wall close to the pixel definition layer and a second end surface of the isolation wall away from the pixel definition layer being within a vertical projection of the pixel definition layer;

[0035] a second electrode layer, the second electrode layer being disposed on a side of the light-emitting functional layer away from the first electrode layer and a side of the isolation wall away from the pixel definition layer, wherein the second electrode layer on the side of the isolation wall away from the pixel definition layer and the second electrode layer on the side of the light-emitting functional layer away from the first electrode layer are disconnected at a sidewall of the isolation wall;

[0036] a conductive connection layer, the conductive connection layer being disposed on a side of the second electrode layer away from the first electrode layer, the conductive connection layer being used to connect the second electrode layer on a side of the isolation wall away from the pixel definition layer and the second electrode layer on a side of the light-emitting functional layer away from the first electrode layer, and the thickness of the conductive connection layer at the sidewall of the isolation wall being less than the thickness of the conductive connection layer in other areas;

[0037] The encapsulation layer is arranged on a side of the conductive connection layer away from the second electrode layer.

[0038] The present invention provides a method for preparing an organic electroluminescent panel, which forms an isolation wall on a side of a pixel definition dam away from a first electrode layer, and a first end face of the isolation wall close to the pixel definition layer is within a vertical projection of the pixel definition layer, and a second end face of the isolation wall away from the pixel definition layer is within a vertical projection of the pixel definition layer. When forming the first electrode layer, due to the obstruction of the second end face of the isolation wall, the second electrode layer will not be deposited on the side wall of the isolation wall. Therefore, the second electrode layer is not continuous, but is disconnected at the side wall of the isolation wall. Then, a conductive connection layer is formed on a side of the second electrode layer away from the first electrode layer to electrically connect the originally discontinuous second electrode layer. The thickness of the conductive connection layer at the side wall of the isolation wall is less than the thickness of the conductive connection layer in other areas. The resistance of the conductive connection layer at the side wall of the isolation wall is relatively large. When a short circuit occurs in an organic electroluminescent device, the short-circuit current will generate a large amount of heat in the conductive connection layer at the side wall of the isolation wall, causing the location to fuse, thereby isolating the organic electroluminescent device from other organic electroluminescent devices, avoiding large-scale damage to the organic electroluminescent panel, reducing the maintenance rate and maintenance cost, and improving user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0040] Figure 1A flow chart of a method for preparing an organic electroluminescent panel provided by the present invention;

[0041] Figure 2 A flow chart of the preparation process of an organic electroluminescent panel provided by the present invention;

[0042] Figure 3 The present invention provides a process flow for preparing an organic electroluminescent panel precursor;

[0043] Figure 4 is a front view of the first electrode layer of the present invention;

[0044] Figure 5 A schematic structural diagram of a tandem organic electroluminescent device provided by the present invention;

[0045] Figure 6 This is a schematic structural diagram of an organic electroluminescent panel provided by the present invention. DETAILED DESCRIPTION

[0046] To make the technical problems solved, the technical solutions adopted, and the technical effects achieved by the present invention more clearly understood, the technical solutions of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. It is apparent that the described embodiments are only some of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0047] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0048] In the present invention, unless otherwise expressly specified and limited, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, the first feature being "above", "above" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature includes the first feature being directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature. In addition, the terms "first" and "second" are only used to distinguish in description and have no special meaning.

[0049] Figure 1 This is a flow chart of a method for preparing an organic electroluminescent panel provided by the present invention. Figure 2 The present invention provides a flow chart of a process for preparing an organic electroluminescent panel. It should be noted that: Figure 2 A partial area of ​​the organic electroluminescent panel is shown, not the entire area, e.g. Figure 1 、 2 As shown, the method for preparing an organic electroluminescent panel includes the following steps:

[0050] S101, preparing an organic electroluminescent panel precursor.

[0051] In some embodiments of the present invention, Figure 2 As shown, the organic electroluminescent panel precursor includes a carrier substrate 110, a first electrode layer 120 and a pixel definition layer 130. The carrier substrate 110 can be a transparent substrate with high light transmittance, including a glass substrate and a substrate made of organic materials, which is not limited in the present invention. The first electrode layer 120 is arranged on one side of the carrier substrate 110. In some embodiments of the present invention, the first electrode layer 120 can be an anode layer, and the material can be indium tin oxide (ITO). In other embodiments of the present invention, the first electrode layer 120 can also be a cathode layer, which is not limited in the present invention. The pixel definition layer 130 is arranged on the side of the first electrode layer 120 away from the carrier substrate 110. The pixel definition layer 130 includes a plurality of intersecting (for example, intersecting in a grid-like manner) pixel definition dams 131, and the plurality of intersecting pixel definition dams 131 form a plurality of openings 132. Exemplarily, the pixel definition layer 130 can be made of an insulating material.

[0052] In some embodiments of the present invention, the organic electroluminescent panel precursor further includes a metal grid 140 comprising a plurality of intersecting metal wires 141 arranged in a grid pattern. Metal grid 140 is formed on the side of first electrode layer 120 facing away from carrier substrate 110. Metal grid 140 and first electrode layer 120 form a composite electrode layer, which can improve the conductivity of first electrode layer 120, reduce voltage drop, and enhance the energy efficiency of the organic electroluminescent panel. Exemplarily, metal grid 140 can be made of a highly conductive metal material, such as silver, copper, molybdenum, or aluminum, although this is not a limitation of the present invention.

[0053] Figure 3 The process flow for preparing the organic electroluminescent panel precursor provided by the present invention needs to be explained as follows: Figure 3 A partial area of ​​the organic electroluminescent panel is shown, not the entire area, e.g. Figure 3 As shown, in some embodiments of the present invention, the preparation process of the organic electroluminescent panel precursor is as follows:

[0054] 1. Provide a carrier substrate.

[0055] In the embodiment of the present invention, the carrier substrate 110 may be pre-processed (eg, cleaned, irradiated with ultraviolet light, dried, etc.) to remove foreign matter from the carrier substrate 110 .

[0056] 2. Form a first electrode layer on one side of the carrier substrate.

[0057] For example, the first electrode layer 120 may be formed on one side of the carrier substrate 110 by magnetron sputtering. The thickness of the first electrode layer 120 is in the range of 80 nm to 150 nm.

[0058] 3. Form a metal layer on the side of the first electrode layer away from the carrier substrate.

[0059] In some embodiments of the present invention, a metal layer 140 ′ may be formed on a side of the first electrode layer 120 away from the carrier substrate 110 by magnetron sputtering. The thickness of the metal layer 140 ′ is in a range of 200 nm to 500 nm.

[0060] 4. Patterning the metal layer to obtain a metal grid.

[0061] Figure 4 is a front view of the first electrode layer of the present invention, illustratively, as Figure 3 、 4As shown, the first electrode layer is divided into a light-emitting area AA and a non-light-emitting area BA, and the non-light-emitting area BA surrounds the light-emitting area AA. Exemplarily, the light-emitting area AA corresponds to the area where the organic electroluminescent panel can emit light, for example, most of the central area, and the non-light-emitting area BA corresponds to the area where the organic electroluminescent panel cannot emit light, for example, the edge area around it. In some embodiments of the present invention, the metal layer 140' can be patterned by exposure, development, and wet etching processes to form a metal grid 140 in the light-emitting area AA. Exemplarily, the line width of the metal lines 141 in the metal grid 140 is 10μm-20μm, and the spacing between two adjacent metal lines 141 is 300μm-1000μm. For example, in a specific embodiment of the present invention, the metal layer 140' is a composite laminate structure of molybdenum-aluminum-molybdenum, wherein the thickness of the molybdenum layer is 100 nm and the thickness of the aluminum layer is 500 nm. The metal layer 140' is patterned using a standard yellow light process, and the etching solution is a nitric acid-based etching solution (HNO3:H3PO4:CH3COOH=4:5:1) at a temperature of 40-50°C.

[0062] It should be noted that, in some embodiments of the present invention, the organic electroluminescent panel precursor may not be provided with a metal grid, and the above process steps 3 and 4 may be omitted.

[0063] 5. Patterning the first electrode layer to form a second electrode overlapping region in the non-luminescent region, wherein the second electrode overlapping region is insulated from the rest of the first electrode layer.

[0064] In an embodiment of the present invention, the first electrode layer 120 is patterned to form a second electrode overlapping region 121 within the non-luminescent area BA. The second electrode overlapping region 121 is insulated and isolated from the rest of the first electrode layer 120. In a specific embodiment of the present invention, the first electrode layer 120 is an ITO layer, and the first electrode layer 120 is patterned using a standard yellow light process. The etching is performed using a 50:3:50 hydrochloric acid-nitric acid system for 1-5 minutes.

[0065] 6. Form a pixel definition layer on the side of the first electrode layer away from the carrier substrate.

[0066] In the embodiment of the present invention, the pixel definition layer 130 is formed on the side of the first electrode layer 120 away from the carrier substrate 110. Exemplarily, the pixel definition layer 130 is formed in the light emitting area AA on the side of the first electrode layer 120 away from the carrier substrate 110.

[0067] In the embodiment of the present invention, if the organic electroluminescent panel precursor is provided with a metal grid 140 , the pixel definition dam 131 formed will cover the metal wire 141 and play a role of insulation protection.

[0068] For example, in a specific embodiment of the present invention, a spin coating process is used to spin-coat an epoxy resin (SU-8 3005) photoresist 130' on the side of the first electrode layer 120 away from the carrier substrate 110, with a spin coating thickness of 1.5-3 μm (rotation speed 1500-3000 rpm), and pre-baked in stages (first at 65°C for 2 minutes, then at 95°C for 5 minutes) to eliminate the solvent and stabilize the film; a 365nm i-line light source is used, and the exposure dose is 150-200mJ / cm 2 , define micron-level openings through the mask; development and post-curing: use PGMEA developer for 30-60 seconds to remove the unexposed areas, followed by gradient curing (first drying at 120°C for 10 minutes, then drying at 200°C for 30 minutes).

[0069] S102 , forming an isolation layer on a side of the pixel definition layer away from the first electrode layer.

[0070] In an embodiment of the present invention, an isolation layer 150 is formed on a side of the pixel definition layer 130 away from the first electrode layer 120. The isolation layer 150 includes a plurality of intersecting isolation walls 151. The isolation walls 151 are formed on the pixel definition dam 131. The first end surface of the isolation wall 151 close to the pixel definition layer 130 (the lower end surface of the isolation wall 151 in the figure) and the second end surface of the isolation wall 151 away from the pixel definition layer 130 (the upper end surface of the isolation wall 151 in the figure) are within the vertical projection of the pixel definition layer 130. Exemplarily, the thickness of the isolation layer 150 ranges from 1 μm to 5 μm.

[0071] For example, in some embodiments of the present invention, the cross-section of the isolation wall 151 is an inverted trapezoid, and the two base angles of the inverted trapezoid (i.e., the angles between the upper end surface and the side wall in the figure) are both less than 90°. For example, the two base angles of the inverted trapezoid are 50°-70°.

[0072] For example, in one embodiment of the present invention, a layer of negative photoresist 150' (JSR THB-151N) can be pre-spin-coated on the side of the pixel definition layer 130 away from the first electrode layer 120. The spin-coating process is performed at a rotation speed of 1000-6000 r / min, with a photoresist thickness of 3 μm-10 μm, a pre-bake temperature of 85°C-100°C, and a drying time of 1-3 minutes. Development is then performed using a 0.8%-1.2% KOH solution for 30-60 seconds to remove insufficiently cross-linked areas. After development, the bottom line width of the inverted trapezoid is 5 μm-10 μm, and the bottom width (i.e., the width of the upper end face in the figure) is greater than the top width by 15-30%. Subsequently, hard baking is performed at a baking temperature of 115-130°C for 3-10 minutes to enhance the mechanical strength of the photoresist and reduce the risk of structural collapse in subsequent processes.

[0073] It should be noted that, in the embodiment of the present invention, when forming the isolation layer 150 on the side of the pixel definition layer 130 away from the first electrode layer 120 , no isolation wall is formed on the pixel definition dam 131 near the non-luminous area BA.

[0074] In some embodiments of the present invention, after preparing the isolation layer 150, the substrate is ultrasonically cleaned in sequence using acetone, isopropyl alcohol, and deionized water to remove surface contaminants, and then oxygen plasma activation treatment is performed on the surface of the isolation layer 150 (power 50W-100W, time 30-60 seconds) to increase the surface hydroxyl density. The oxygen plasma activation treatment can enhance the bonding strength between the subsequent conductive connection layer and the side wall of the isolation wall 151, thereby avoiding the breakage of the conductive connection layer caused by the hydrophobicity of the photoresist surface.

[0075] S103 , forming a light-emitting functional layer in the opening.

[0076] In an embodiment of the present invention, the stacked structure prepared in the above step 102 is transferred to a vacuum evaporation chamber for evaporation to form a light-emitting functional layer 160 in the opening 132. Exemplarily, the light-emitting functional layer 160 may include an electron injection layer, an electron transport layer, a light-emitting layer, a hole transport layer, a hole injection layer, etc., which are not limited in the present invention. Exemplarily, in a specific embodiment of the present invention, an open mask is used in the process of evaporating the light-emitting functional layer. Therefore, the light-emitting functional layer 160 will not only fill the opening 132, but also cover the upper surface of the isolation wall 151. However, since the first end face of the isolation wall 151 close to the pixel definition layer 130 is within the vertical projection of the pixel definition layer 130 and the second end face of the isolation wall 151 away from the pixel definition layer 130 is within the vertical projection of the pixel definition layer 130, the light-emitting functional layer 160 will not be deposited on the side wall of the isolation wall 151. The light-emitting functional layer 160 is discontinuous, but is disconnected at the side wall of the isolation wall 151. In other embodiments of the present invention, a fine mask may also be used to block the area outside the opening 132 and form the light-emitting functional layer 160 only within the opening 132 .

[0077] S104 , forming a second electrode layer on a side of the light-emitting functional layer away from the first electrode layer and on a side of the isolation wall away from the pixel definition layer.

[0078] In an embodiment of the present invention, the stacked structure prepared in step S103 can be transferred to a magnetron sputtering chamber to form a second electrode layer 170 on a side of the light-emitting functional layer 160 away from the first electrode layer 120 and on a side of the isolation wall 151 away from the pixel definition layer 130. The second electrode layer 170 on the side of the isolation wall 151 away from the pixel definition layer 130 and the second electrode layer 170 on the side of the light-emitting functional layer 160 away from the first electrode layer 120 are disconnected at the sidewall of the isolation wall 151. Since an open mask is used when preparing the light-emitting functional layer 160, the light-emitting functional layer 160 is also formed on the upper surface of the isolation wall 151. Therefore, the second electrode layer 170 formed in this step actually covers the light-emitting functional layer 160 in the opening 132 and the light-emitting functional layer 160 on the isolation wall 151. Due to the obstruction of the upper end surface of the isolation wall 151, the second electrode layer 170 is not deposited on the sidewall of the isolation wall 151. Therefore, the second electrode layer 170 is not continuous but is interrupted at the sidewall of the isolation wall 151. Exemplarily, the second electrode layer 170 can be a cathode, made of aluminum, and having a thickness of approximately 200 nm.

[0079] In the embodiment of the present invention, while preparing the second electrode layer 170, a bonding electrode 171 is formed between the light-emitting area AA and the second electrode bonding area 121. One end of the bonding electrode 171 is connected to the second electrode layer 170, and the other end is connected to the second electrode bonding area 121, thereby connecting the second electrode layer 170 and the second electrode bonding area 121. The second electrode bonding area 121 is used to input a second electrode signal, such as a ground signal.

[0080] The light-emitting functional layer 160 in each opening 132 and the first electrode layer 120 and the second electrode layer 170 on both sides thereof constitute an organic electroluminescent device. In an embodiment of the present invention, the first electrode layer 120 is an anode and the second electrode layer 170 is a cathode. In some embodiments of the present invention, the organic electroluminescent device may be a single organic electroluminescent device or a tandem organic electroluminescent device, which is not limited in the present invention. In a specific embodiment of the present invention, the organic electroluminescent device is a tandem organic electroluminescent device (Tandem OLED), which is a display technology formed by stacking two OLED devices together. Its working principle is based on the basic structure of OLED, and the two OLED light-emitting layers are connected in series through a carrier generation layer (CGL). After the holes and electrons in the first light-emitting layer recombine to emit light, the remaining holes and electrons pass through the carrier generation layer and recombine again in the second light-emitting layer to emit light.

[0081] Figure 5 A schematic diagram of the structure of a tandem organic electroluminescent device provided by the present invention is shown in FIG. Figure 5As shown, the tandem organic electroluminescent device comprises:

[0082] The carrier generation layer includes an N-type material layer and a P-type material layer. For example, the N-type material layer is Bphen (4,7-diphenyl-1,10-phenanthroline) doped with Liq (8-hydroxyquinoline lithium) with a doping ratio of 70% and a thickness of 30 nm. The P-type material layer is NPB (N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine) doped with F4-TCNQ (2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone) with a doping ratio of 4% and a thickness of 50 nm.

[0083] The first light-emitting layer is disposed on the side of the N-type material layer away from the P-type material layer. Electrons generated by the carrier generation layer migrate toward the first light-emitting layer, where they recombine with holes, generating photons and emitting light. Exemplarily, the material of the first light-emitting layer can be Bepp2-doped Ir(ppy)3, with a doping ratio of 5% and a thickness of 30nm. Bepp2 is bis(2-(2-phenylpyridinium)pyridine)beryllium, and Ir(ppy)3 is tris(2-phenylpyridinium)iridium.

[0084] A first hole transport layer is disposed on the side of the first light-emitting layer away from the carrier generation layer. The first hole transport layer is used to transport holes from the hole injection layer to the first light-emitting layer, where they recombine with electrons in the first light-emitting layer to emit light. Exemplarily, the material of the first hole transport layer can be NPB, with a thickness of 20 nm.

[0085] A hole injection layer is disposed on the side of the first hole transport layer away from the first light-emitting layer. The hole injection layer facilitates the smooth entry of holes from the anode into the first hole transport layer. Exemplarily, the hole injection layer can be made of NPB-doped F4-TCNQ with a doping ratio of 4% and a thickness of 50 nm.

[0086] The anode is disposed on a side of the hole injection layer away from the first hole transport layer. The anode is used to inject holes into the hole injection layer. Exemplarily, the anode material can be ITO (indium tin oxide) with a thickness of 100 nm.

[0087] A second hole transport layer is disposed on the side of the P-type material layer facing away from the N-type material layer. During operation of the tandem organic light-emitting device, carriers are generated and separated at the interface between the P-type material layer and the second hole transport layer. The second hole transport layer is used to transport the generated holes to the second light-emitting layer. Exemplarily, the material of the second hole transport layer can be NPB, with a thickness of 20 nm.

[0088] A second light-emitting layer is disposed on the side of the second hole-transport layer away from the carrier-generating layer. Holes from the carrier-generating layer recombine with electrons in the second light-emitting layer to produce light. Exemplarily, the second light-emitting layer can be made of Bepp2-doped Ir(ppy)3 with a doping ratio of 5% and a thickness of 50 nm.

[0089] An electron transport layer (ETL) is positioned on the side of the second light-emitting layer away from the second hole transport layer. The ETL is used to transport electrons generated by the cathode to the second light-emitting layer, where they recombine with holes to emit light. For example, the ETL can be made of Bphen-doped Liq with a doping ratio of 70% and a thickness of 30 nm.

[0090] The cathode is disposed on the side of the electron transport layer away from the second light-emitting layer. The cathode is used to generate electrons. Exemplarily, the cathode is made of Al and has a thickness of 200 nm.

[0091] S105 , forming a conductive connection layer on a side of the second electrode layer away from the first electrode layer.

[0092] In an embodiment of the present invention, a conductive connection layer 180 is formed on a side of the second electrode layer 170 away from the first electrode layer 120. The conductive connection layer 180 is used to connect the second electrode layer 170 on the side of the isolation wall 151 away from the pixel definition layer 130 and the second electrode layer 170 on the side of the light-emitting functional layer 160 away from the first electrode layer 120. That is, the conductive connection layer 180 electrically connects the originally discontinuous second electrode layer 170, and the thickness of the conductive connection layer 180 at the sidewall of the isolation wall 151 is less than the thickness of the conductive connection layer 180 in other areas. The material of the conductive connection layer 180 can be AZO (aluminum-doped zinc oxide) or aluminum-doped In2O3, with a thickness ranging from 20nm to 100nm.

[0093] In the embodiment of the present invention, the conductive connection layer 180 may be prepared by atomic layer deposition or magnetron sputtering.

[0094] The process parameters of the atomic layer deposition method are as follows: using a mixture of DEZ (diethyl zinc), TMA (trimethyl aluminum) and deionized water as a precursor, controlling the deposition temperature at 80°C-100°C, a growth rate of 0.1-0.15 nm / cycle per cycle, a total deposition cycle of 200-1000 times, and a final thickness of 20 nm-100 nm; after the deposition is completed, annealing is performed in a nitrogen atmosphere (800-100°C, time 10-30 minutes) to make the resistivity of the conductive connection layer 180 less than 10 -3 Ω·cm, the square resistance is stable at <100Ω / sq, and the contact resistance with the second electrode layer 170 is <0.5Ω·cm 2The doping ratio of aluminum in the second electrode layer 170 can be controlled by the number of pulses.

[0095] The process parameters of the magnetron sputtering method are: the target material and the substrate form an angle of 20°-60°, and the substrate rotates at a constant speed of 5rpm-15rpm, so that the conductive material preferentially fills the bottom and sides of the high aspect ratio structure (i.e., the bottom and side walls of the isolation wall 151), avoiding the "eaves effect" of vertical sputtering, and ensuring that the side walls of the isolation wall 151 can also be deposited with a conductive connection layer 180, which electrically connects the originally discontinuous second electrode layer 170. Among them, the substrate is the stacked structure prepared in the above step S104, including an organic electroluminescent panel precursor, an isolation layer, a light-emitting functional layer and a second electrode layer. In addition, the sputtering voltage is reduced to 400V to reduce ion bombardment damage. The RF power is controlled at 300W and the sputtering time is 2min.

[0096] S106 , forming an encapsulation layer on a side of the conductive connection layer away from the second electrode layer to obtain an organic electroluminescent panel.

[0097] In the embodiment of the present invention, an encapsulation layer 191 is formed on a side of the conductive connection layer 180 away from the second electrode layer 170 to obtain an organic electroluminescent panel. Exemplarily, the encapsulation layer 191 may also cover the sidewalls of the stacked structure.

[0098] In some embodiments of the present invention, after preparing the encapsulation layer 191, the method further includes:

[0099] A light extraction layer 192 is formed on the side of the carrier substrate 110 away from the first electrode layer 120 (the light-emitting side). The light extraction layer 192 can improve the light uniformity of the organic electroluminescent panel. For example, in one embodiment of the present invention, a mixed film of TiO2 nanoparticles (particle size 50-100nm) and PDMS (polydimethylsiloxane) can be formed on the side of the carrier substrate 110 away from the first electrode layer 120 by a coating method, and the mixed film is cured to obtain the light extraction layer 192. The mass fraction of TiO2 is 10-20%, the film thickness is 2-10μm, and the surface of TiO2 is modified with a silane coupling agent (APTES) to improve the dispersion uniformity. In another embodiment of the present invention, the light extraction layer 192 can also be a mixed film of SiO2 micron particles (particle size 1-2um) and PDMS or PMMA (polymethyl methacrylate).

[0100] The present invention provides a method for preparing an organic electroluminescent panel, which forms an isolation wall on a side of a pixel definition dam away from a first electrode layer, and a first end face of the isolation wall close to the pixel definition layer is within a vertical projection of the pixel definition layer, and a second end face of the isolation wall away from the pixel definition layer is within a vertical projection of the pixel definition layer. When forming the first electrode layer, due to the obstruction of the second end face of the isolation wall, the second electrode layer will not be deposited on the side wall of the isolation wall. Therefore, the second electrode layer is not continuous, but is disconnected at the side wall of the isolation wall. Then, a conductive connection layer is formed on a side of the second electrode layer away from the first electrode layer to electrically connect the originally discontinuous second electrode layer. The thickness of the conductive connection layer at the side wall of the isolation wall is less than the thickness of the conductive connection layer in other areas. The resistance of the conductive connection layer at the side wall of the isolation wall is relatively large. When a short circuit occurs in an organic electroluminescent device, the short-circuit current will generate a large amount of heat in the conductive connection layer at the side wall of the isolation wall, causing the location to fuse, thereby isolating the organic electroluminescent device from other organic electroluminescent devices, avoiding large-scale damage to the organic electroluminescent panel, reducing the maintenance rate and maintenance cost, and improving user experience.

[0101] The present invention further provides an organic electroluminescent panel, which is prepared by the organic electroluminescent panel preparation method provided by any of the aforementioned embodiments of the present invention. Figure 6 This is a schematic diagram of the structure of an organic electroluminescent panel provided by the present invention. It should be noted that: Figure 6 Shows a partial area of ​​the organic electroluminescent panel, not all, for example, Figure 6 As shown, the organic electroluminescent panel includes:

[0102] a carrier substrate 110;

[0103] The first electrode layer 120 is disposed on one side of the carrier substrate 110 .

[0104] The pixel definition layer 130 is disposed on a side of the first electrode layer 120 away from the carrier substrate 110 . The pixel definition layer 130 includes a plurality of intersecting pixel definition dams 131 . The plurality of intersecting pixel definition dams 131 form a plurality of openings.

[0105] The light-emitting functional layer 160 is disposed in the opening.

[0106] The isolation layer 150 is arranged on the side of the pixel definition layer 130 away from the first electrode layer 120. The isolation layer 150 includes a plurality of crossed isolation walls 151. The isolation walls 151 are formed on the pixel definition dam 131. The first end surface of the isolation wall 151 close to the pixel definition layer 130 (the lower end surface of the isolation wall 151 in the figure) is within the vertical projection of the pixel definition layer 130, and the second end surface of the isolation wall 151 away from the pixel definition layer 130 (the upper end surface of the isolation wall 151 in the figure) is within the vertical projection of the pixel definition layer 130.

[0107] The second electrode layer 170 is arranged on the side of the light-emitting functional layer 160 away from the first electrode layer 120 and the side of the isolation wall 151 away from the pixel definition layer 130, wherein the second electrode layer 170 on the side of the isolation wall 151 away from the pixel definition layer 130 and the second electrode layer 170 on the side of the light-emitting functional layer 160 away from the first electrode layer 120 are disconnected at the side wall of the isolation wall 151.

[0108] The conductive connection layer 180 is arranged on the side of the second electrode layer 170 away from the first electrode layer 120. The conductive connection layer 180 is used to connect the second electrode layer 170 on the side of the isolation wall 151 away from the pixel definition layer 130 and the second electrode layer 170 on the side of the light-emitting functional layer 160 away from the first electrode layer 120, that is, the conductive connection layer 180 electrically connects the originally discontinuous second electrode layer 170, and the thickness of the conductive connection layer 180 at the side wall of the isolation wall 151 is less than the thickness of the conductive connection layer 180 in other areas.

[0109] The encapsulation layer 191 is disposed on a side of the conductive connection layer 180 away from the second electrode layer 170 . Exemplarily, the encapsulation layer 191 may also cover the sidewalls of the stacked structure.

[0110] The organic electroluminescent panel provided by the present invention has a first end face of the isolation wall close to the pixel definition layer and a second end face of the isolation wall away from the pixel definition layer within a vertical projection of the pixel definition layer. Due to the obstruction of the second end face of the isolation wall, the second electrode layer will not be deposited on the side wall of the isolation wall. Therefore, the second electrode layer is not continuous, but is disconnected at the side wall of the isolation wall. The conductive connection layer electrically connects the originally discontinuous second electrode layer, and the thickness of the conductive connection layer at the side wall of the isolation wall is less than the thickness of the conductive connection layer in other areas. The resistance of the conductive connection layer at the side wall of the isolation wall is relatively large. When a short circuit occurs in an organic electroluminescent device, the short-circuit current will generate a large amount of heat in the conductive connection layer at the side wall of the isolation wall, causing the position to fuse, thereby isolating the organic electroluminescent device from other organic electroluminescent devices, avoiding large-scale damage to the organic electroluminescent panel, reducing the maintenance rate and maintenance cost, and improving user experience.

[0111] In some embodiments of the present invention, the organic electroluminescent panel is divided into a light-emitting area AA and a non-light-emitting area BA. The non-light-emitting area BA surrounds the light-emitting area AA. Exemplarily, the light-emitting area AA corresponds to the area where the organic electroluminescent panel can emit light, such as most of the central area, and the non-light-emitting area BA corresponds to the area where the organic electroluminescent panel cannot emit light, such as the edge area around it. A metal grid 140 is also provided in the light-emitting area AA on the side of the first electrode layer 120 away from the carrier substrate 110. The metal grid 140 includes a plurality of metal wires 141 that cross in a grid shape. The pixel definition dam 131 covers the metal wires 141 and serves as an insulating protection. The metal grid 140 is formed on the side of the first electrode layer 120 away from the carrier substrate 110. The metal grid 140 and the first electrode layer 120 form a composite electrode layer, which can improve the conductivity of the first electrode layer 120, reduce the voltage drop, and improve the energy efficiency of the organic electroluminescent panel.

[0112] In some embodiments of the present invention, a second electrode overlapping region 121 is provided in the non-luminous region BA of the first electrode layer 120 . The second electrode overlapping region 121 is patterned by the first electrode layer 120 and is insulated and isolated from the rest of the first electrode layer 120 .

[0113] In some embodiments of the present invention, no isolation wall is disposed on the pixel definition dam 131 near the non-emission area BA.

[0114] In some embodiments of the present invention, the cross-section of the isolation wall 151 is an inverted trapezoid, and both base angles of the inverted trapezoid (i.e., the angles between the upper end surface and the sidewall in the figure) are less than 90°. For example, the base angles of the inverted trapezoid are 50°-70°. The bottom line width of the inverted trapezoid is 5μm-10μm, and the bottom width (i.e., the width of the upper end surface in the figure) is 15-30% greater than the top width.

[0115] In some embodiments of the present invention, the light-emitting functional layer 160 will not only fill the opening 132, but also cover the upper surface of the isolation wall 151. However, since the first end surface of the isolation wall 151 close to the pixel definition layer 130 and the second end surface of the isolation wall 151 away from the pixel definition layer 130 are within the vertical projection of the pixel definition layer 130, the light-emitting functional layer 160 will not be deposited on the side wall of the isolation wall 151. The light-emitting functional layer 160 is discontinuous, but is disconnected at the side wall of the isolation wall 151.

[0116] In some embodiments of the present invention, the second electrode layer 170 covers the light-emitting functional layer 160 in the opening 132 and the light-emitting functional layer 160 on the isolation wall 151. Due to the obstruction of the upper end surface of the isolation wall 151, the second electrode layer 170 is not deposited on the sidewall of the isolation wall 151. Therefore, the second electrode layer 170 is not continuous but is interrupted at the sidewall of the isolation wall 151.

[0117] In some embodiments of the present invention, a bonding electrode 171 is formed between the light-emitting area AA and the second electrode bonding area 121. One end of the bonding electrode 171 is connected to the second electrode layer 170, and the other end is connected to the second electrode bonding area 121, thereby connecting the second electrode layer 170 and the second electrode bonding area 121. The second electrode bonding area 121 is used to input a second electrode signal, such as a ground signal. The bonding electrode 171 and the second electrode layer 170 are formed in the same process.

[0118] In some embodiments of the present invention, the organic electroluminescent panel further includes a light extraction layer 192 , which is disposed on a side of the carrier substrate 110 away from the first electrode layer 120 (the light extraction side). The light extraction layer 192 can improve the light extraction uniformity of the organic electroluminescent panel.

[0119] It should be noted that the materials, dimensions and other features of each layer in the organic electroluminescent panel have been described in detail in the aforementioned embodiments, and will not be repeated herein.

[0120] The present invention further provides a light-emitting device, which includes the organic electroluminescent panel provided by any of the aforementioned embodiments of the present invention. The light-emitting device can be used for lighting or backlighting, etc., and the present invention does not limit this.

[0121] In the description of this document, it should be understood that the terms "up", "down", "left", "right", and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0122] In this specification, reference to terms such as "one embodiment" or "example" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example.

[0123] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0124] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are intended solely to illustrate the principles of the present invention and are not to be construed in any way as limiting the scope of protection of the present invention. Based on the explanations herein, those skilled in the art will readily conceive of other specific embodiments of the present invention without inventive effort, and such embodiments will fall within the scope of protection of the present invention.

Claims

1. A method for preparing an organic electroluminescent panel, characterized in that: include: An organic electroluminescent panel precursor is prepared, the organic electroluminescent panel precursor comprising a carrier substrate, a first electrode layer, and a pixel definition layer, wherein the first electrode layer is disposed on one side of the carrier substrate, the pixel definition layer is disposed on a side of the first electrode layer away from the carrier substrate, and the pixel definition layer comprises a plurality of intersecting pixel definition dams, wherein the plurality of intersecting pixel definition dams form a plurality of openings; forming an isolation layer on a side of the pixel definition layer away from the first electrode layer, the isolation layer comprising a plurality of intersecting isolation walls, the isolation walls being formed on the pixel definition dam, a first end surface of the isolation wall close to the pixel definition layer and a second end surface of the isolation wall away from the pixel definition layer being within a vertical projection of the pixel definition layer; forming a light-emitting functional layer in the opening; forming a second electrode layer on a side of the light-emitting functional layer away from the first electrode layer and on a side of the isolation wall away from the pixel definition layer, wherein the second electrode layer on the side of the isolation wall away from the pixel definition layer and the second electrode layer on the side of the light-emitting functional layer away from the first electrode layer are disconnected at a sidewall of the isolation wall; forming a conductive connection layer on a side of the second electrode layer away from the first electrode layer, the conductive connection layer being used to connect the second electrode layer on a side of the isolation wall away from the pixel definition layer and the second electrode layer on a side of the light-emitting functional layer away from the first electrode layer, and a thickness of the conductive connection layer at a sidewall of the isolation wall being less than a thickness of the conductive connection layer in other areas; An encapsulation layer is formed on a side of the conductive connection layer away from the second electrode layer to obtain an organic electroluminescent panel.

2. The method for preparing an organic electroluminescent panel according to claim 1, wherein: Preparation of an organic electroluminescent panel precursor, comprising: providing a carrier substrate; forming a first electrode layer on one side of the carrier substrate; A pixel definition layer is formed on a side of the first electrode layer away from the carrier substrate.

3. The method for preparing an organic electroluminescent panel according to claim 2, wherein: The first electrode layer is divided into a light-emitting area and a non-light-emitting area, and the non-light-emitting area surrounds the light-emitting area. After the first electrode layer is formed on one side of the carrier substrate, the method further includes: performing patterning on the first electrode layer to form a second electrode overlapping region in the non-luminescent region, wherein the second electrode overlapping region is insulated and isolated from the rest of the first electrode layer; Accordingly, a pixel definition layer is formed on a side of the first electrode layer away from the carrier substrate, comprising: A pixel definition layer is formed in the light emitting area on a side of the first electrode layer away from the carrier substrate.

4. The method for preparing an organic electroluminescent panel according to claim 3, wherein: During the process of forming the isolation layer on the side of the pixel definition layer away from the first electrode layer, no isolation wall is formed on the pixel definition dam close to the non-luminescent area.

5. The method for preparing an organic electroluminescent panel according to claim 3, wherein: While a second electrode layer is formed on a side of the light-emitting functional layer away from the first electrode layer and a side of the isolation wall away from the pixel definition layer, a overlapping electrode is formed between the light-emitting area and the second electrode overlapping area, and the overlapping electrode is used to connect the second electrode layer and the second electrode overlapping area.

6. The method for preparing an organic electroluminescent panel according to claim 3, wherein: After patterning the first electrode layer, the method further includes: A metal grid is formed in the light emitting region on a side of the first electrode layer away from the carrier substrate.

7. The method for preparing an organic electroluminescent panel according to any one of claims 1 to 5, characterized in that: The cross section of the isolation wall is an inverted trapezoid, and both bottom angles of the inverted trapezoid are less than 90°.

8. The method for preparing an organic electroluminescent panel according to any one of claims 1 to 5, characterized in that: A conductive connection layer is formed on a side of the second electrode layer away from the first electrode layer, comprising: The conductive connection layer is prepared by magnetron sputtering or atomic layer deposition. During the magnetron sputtering process, the target material and the substrate form an angle of 20°-60°, and the substrate rotates at a constant speed of 5rpm-15rpm. The substrate includes the organic electroluminescent panel precursor, the isolation layer, the light-emitting functional layer and the second electrode layer.

9. The method for preparing an organic electroluminescent panel according to any one of claims 1 to 5, characterized in that: After forming an encapsulation layer on a side of the conductive connection layer away from the second electrode layer, the method further includes: A light extraction layer is formed on a side of the carrier substrate away from the first electrode layer.

10. An organic electroluminescent panel, characterized in that: The method for preparing an organic electroluminescent panel according to any one of claims 1 to 9 comprises: a carrier substrate; a first electrode layer, the first electrode layer being disposed on one side of the carrier substrate; a pixel definition layer, the pixel definition layer being disposed on a side of the first electrode layer away from the carrier substrate, the pixel definition layer comprising a plurality of intersecting pixel definition dams, the plurality of intersecting pixel definition dams forming a plurality of openings; a light-emitting functional layer, wherein the light-emitting functional layer is disposed in the opening; an isolation layer, the isolation layer being disposed on a side of the pixel definition layer away from the first electrode layer, the isolation layer comprising a plurality of intersecting isolation walls, the isolation walls being formed on the pixel definition dam, a first end surface of the isolation wall close to the pixel definition layer and a second end surface of the isolation wall away from the pixel definition layer being within a vertical projection of the pixel definition layer; a second electrode layer, the second electrode layer being disposed on a side of the light-emitting functional layer away from the first electrode layer and a side of the isolation wall away from the pixel definition layer, wherein the second electrode layer on the side of the isolation wall away from the pixel definition layer and the second electrode layer on the side of the light-emitting functional layer away from the first electrode layer are disconnected at a sidewall of the isolation wall; a conductive connection layer, the conductive connection layer being disposed on a side of the second electrode layer away from the first electrode layer, the conductive connection layer being used to connect the second electrode layer on a side of the isolation wall away from the pixel definition layer and the second electrode layer on a side of the light-emitting functional layer away from the first electrode layer, and the thickness of the conductive connection layer at the sidewall of the isolation wall being less than the thickness of the conductive connection layer in other areas; The encapsulation layer is arranged on a side of the conductive connection layer away from the second electrode layer.

Images