An organic light emitting diode structure and a method of fabricating the same

Abstract

The application discloses an organic light emitting diode structure and a preparation method thereof. The organic light emitting diode structure comprises a substrate, a first electrode, a light emitting layer, a second electrode and a thin film encapsulation layer which are sequentially stacked; and further comprises at least one aluminum oxide layer arranged between the second electrode and the thin film encapsulation layer, wherein the aluminum oxide layer covers at least a preset surface of the second electrode, and the preset surface is a surface of the second electrode away from the substrate in a thickness direction of the substrate. The application can improve the encapsulation reliability of the organic light emitting diode structure.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic electroluminescence, in particular to an organic light-emitting diode structure and a preparation method thereof. BACKGROUND

[0002] An organic light-emitting diode (OLED) is a kind of optoelectronic device that emits light through carrier injection and recombination. The specific process is that electrons are injected through the cathode, transported to the light-emitting layer through the electron transport material, holes are injected through the anode, transported to the light-emitting layer through the hole transport material, and the electrons and holes are recombined in the light-emitting layer to form excitons. OLED has the characteristics of good light-emitting uniformity, lightness, flexibility, stretchability, etc., and is concerned.

[0003] OLED is extremely sensitive to water and oxygen, so it is necessary to encapsulate the OLED, and the existing OLED encapsulation has poor reliability. SUMMARY

[0004] The present application provides an organic light-emitting diode structure and a preparation method thereof to improve the encapsulation reliability of the organic light-emitting diode structure.

[0005] According to an aspect of the present application, an organic light-emitting diode structure is provided, comprising:

[0006] a substrate, a first electrode, a light-emitting layer, a second electrode and a thin film encapsulation layer which are sequentially stacked;

[0007] Further comprising at least one aluminum oxide layer arranged between the second electrode and the thin film encapsulation layer, wherein the aluminum oxide layer covers at least a preset surface of the second electrode, and the preset surface is a surface of the second electrode away from the substrate in the thickness direction of the substrate.

[0008] Optionally, the oxygen content of the at least one aluminum oxide layer is a constant value.

[0009] Alternatively, the oxygen content of the at least one aluminum oxide layer gradually increases in a direction away from the second electrode.

[0010] Alternatively, the organic light-emitting diode structure comprises at least two aluminum oxide layers, and the oxygen content of the aluminum oxide layer farthest from the second electrode gradually increases in a direction away from the second electrode, and the oxygen content of the other aluminum oxide layers first increases and then decreases.

[0011] Optionally, when the oxygen content of the at least one aluminum oxide layer gradually increases in a direction away from the second electrode:

[0012] The oxygen content of each aluminum oxide layer linearly increases in a direction away from the second electrode.

[0013] Alternatively, the organic light emitting diode structure comprises at least two aluminum oxide layers, and the oxygen content of the at least two aluminum oxide layers increases in a direction away from the second electrode.

[0014] Optionally, the light emitting layer comprises a first surface and a second surface connected to each other, the first surface being a surface of the light emitting layer away from the substrate, and the second surface surrounding the first surface;

[0015] The second electrode comprises a first part and a second part connected to each other;

[0016] The first part is arranged on the first surface, and the second part is arranged on the second surface;

[0017] The aluminum oxide layer covers surfaces of the first part and the second part.

[0018] Optionally, the total thickness of the at least one aluminum oxide layer is greater than or equal to 5 nm.

[0019] Optionally, the material of the second electrode comprises aluminum or aluminum-silver alloy.

[0020] Optionally, the organic light emitting diode structure further comprises:

[0021] A water-oxygen barrier layer arranged between the substrate and the first electrode.

[0022] According to another aspect of the present application, a method for manufacturing an organic light emitting diode is provided, comprising:

[0023] Arranging a first electrode on a surface of a substrate;

[0024] Arranging a light emitting layer on the first electrode;

[0025] Arranging a second electrode on the light emitting layer;

[0026] Arranging at least one aluminum oxide layer on the second electrode; wherein the aluminum oxide layer covers at least a preset surface of the second electrode, and the preset surface is a surface of the second electrode away from the substrate in a thickness direction of the substrate;

[0027] Arranging a thin film encapsulation layer on the aluminum oxide layer.

[0028] Optionally, arranging the at least one aluminum oxide layer on the second electrode comprises:

[0029] Using a device for manufacturing the thin film encapsulation layer to manufacture the at least one aluminum oxide layer.

[0030] Optionally, arranging the at least one aluminum oxide layer on the second electrode comprises:

[0031] During or after evaporation of aluminum on the surface of the second electrode, oxygen is introduced to form the aluminum oxide layer;

[0032] Or, in the process of evaporating aluminum on the surface of the second electrode, oxygen is introduced, and the amount of oxygen introduced is linearly increased, forming an aluminum oxide layer with linearly increased oxygen content in the direction away from the second electrode;

[0033] Or, in the process of evaporating aluminum on the surface of the second electrode, oxygen is introduced, and the amount of oxygen introduced is linearly increased, forming an aluminum oxide layer with linearly increased oxygen content in the direction away from the second electrode;

[0034] Or, in the process of evaporating aluminum on the surface of the second electrode, oxygen is introduced, and the amount of oxygen introduced is linearly increased, forming an aluminum oxide layer with linearly increased oxygen content in the direction away from the second electrode;

[0035] The organic light-emitting diode structure provided by the technical scheme of the embodiment of the present application sets at least one aluminum oxide layer between the second electrode and the thin film packaging layer. Since the aluminum oxide layer has insulation and good water vapor blocking performance, by setting the aluminum oxide layer on the surface of the second electrode, not only can the second electrode and the light-emitting layer be prevented from being damaged in the process of manufacturing the thin film packaging layer, but also water vapor can be blocked, and the packaging reliability of the organic light-emitting structure is improved.

[0036] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present application, nor is it used to limit the scope of the present application. Other features of the present application will become apparent through the following description. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical scheme in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0038] Figure 1 is a schematic diagram of an organic light-emitting diode structure provided by the first embodiment of the present application;

[0039] Figure 2 is a schematic diagram of another organic light-emitting diode structure provided by the first embodiment of the present application;

[0040] Figure 3 is a schematic diagram of another organic light-emitting diode structure provided by the first embodiment of the present application;

[0041] Figure 4 is a schematic diagram of another organic light-emitting diode structure provided by the first embodiment of the present application;

[0042] Figure 5is a flow chart of a preparation method of an organic light emitting diode provided by Embodiment Two of the present application. DETAILED DESCRIPTION

[0043] In order for those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should fall within the scope of protection of the present application.

[0044] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to only those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0045] It is well known that OLED devices are extremely sensitive to water and oxygen, so they need to be packaged. One of the mainstream OLED packaging structures for mass production at present is thin film packaging, and plasma enhanced chemical vapor deposition (PECVD) is used in thin film packaging. When making a thin film packaging layer, PECVD needs to use a relatively high power, usually greater than 1000W. Under such power, the plasma generated in PECVD can easily damage the OLED electrode, which can easily lead to abnormal discharge of PECVD, further damaging the OLED. To solve the problem of damage to the OLED electrode, a thin layer of organic or inorganic material is usually evaporated on the OLED electrode as an electrode protection layer to insulate the OLED electrode and prevent plasma from damaging the electrode. However, the thin organic or inorganic material evaporated in the existing OLED structure does not have the performance of blocking water and oxygen, but has the function of guiding water vapor, which is not conducive to the packaging reliability of the OLED. To solve the above problems, the present application provides the following solutions:

[0046] Embodiment One

[0047] The present application provides an organic light emitting diode structure, Figure 1 is a schematic diagram of an organic light emitting diode structure provided by Embodiment One of the present application, referring toFigure 1 The organic light emitting diode structure comprises: a substrate 10, a first electrode 20, a light emitting layer 30, a second electrode 40 and a thin film encapsulation layer 60 which are sequentially stacked; and further comprises at least one aluminum oxide layer 50 arranged between the second electrode 40 and the thin film encapsulation layer 60, wherein the aluminum oxide layer 50 covers at least a preset surface of the second electrode 40, and the preset surface is a surface of the second electrode 40 away from the substrate 10 in a thickness direction of the substrate 10.

[0048] The substrate 10 can be a rigid substrate or a flexible substrate. The rigid substrate can be made of glass. The flexible substrate can be made of at least one of polyimide, polyester, polyethylene naphthalate glycol. The first electrode 20 can be a light-transmitting electrode, and the second electrode 40 can be a reflective electrode. The light emitting layer 30 emits light through the first electrode 20 and the substrate 10. The material of the first electrode 20 can include indium tin oxide, indium zinc oxide, or a combination of indium tin oxide and indium zinc oxide. The first electrode 20 can also have a stacked structure of indium tin oxide / silver / indium tin oxide. The material of the second electrode 40 can be a metal material, for example, aluminum or aluminum-silver alloy. The first electrode 20 and the second electrode 40 can be one of an anode and a cathode. The light emitting layer 30 and the cathode can further comprise a hole injection layer, a hole transport layer and an electron blocking layer. The light emitting layer 30 and the anode can further comprise a hole blocking layer, an electron transport layer and an electron injection layer.

[0049] The thin film encapsulation layer 60 has a water and oxygen blocking effect, and is used to protect the first electrode 20, the light emitting layer 30 and the second electrode 40. The material of the thin film encapsulation layer 60 can include silicon nitride and / or silicon oxide. The thin film encapsulation layer 60 can be formed by a process such as plasma enhanced chemical vapor deposition. The aluminum oxide layer 50 can be one layer, two layers or multiple layers arranged between the second electrode 40 and the thin film encapsulation layer 60. The oxygen content of the one layer, two layers or multiple layers of aluminum oxide layer 50 can be the same or different. For example, the oxygen content of the at least one aluminum oxide layer 50 gradually increases in a direction away from the second electrode 40.

[0050] The aluminum oxide layer 50 has insulation and good water vapor blocking performance. By arranging the aluminum oxide layer 50 on the surface of the second electrode 40, the second electrode 40 and the light emitting layer 30 can be protected from damage during the manufacturing process of the thin film encapsulation layer 60, and water vapor can be blocked, thereby improving the encapsulation reliability of the organic light emitting structure.

[0051] The organic light emitting diode structure provided by the technical scheme of the embodiment of the present application is provided with at least one aluminum oxide layer 50 between the second electrode 40 and the thin film packaging layer 60. Since the aluminum oxide layer 50 has insulation and good water vapor blocking performance, by arranging the aluminum oxide layer 50 on the surface of the second electrode 40, the second electrode 40 and the light emitting layer 30 can be prevented from being damaged during the manufacturing process of the thin film packaging layer 60, and water vapor can be blocked, thereby improving the packaging reliability of the organic light emitting structure.

[0052] Optionally, the material of the second electrode comprises aluminum or aluminum-silver alloy.

[0053] When the material of the second electrode comprises aluminum or aluminum-silver alloy, the aluminum oxide layer can be prepared during the process of forming the second electrode, or after the second electrode is formed, the aluminum layer is formed on the surface of the second electrode by using the process of forming the second electrode, and then the aluminum layer is treated to form the aluminum oxide layer. That is, the aluminum oxide layer can be directly formed by using the material and process of forming the second electrode, thereby simplifying the process steps.

[0054] Optionally, the aluminum oxide layer can be formed by introducing oxygen to oxidize the surface of the aluminum layer or the aluminum-silver alloy layer after forming the aluminum layer or the aluminum-silver alloy layer with a certain thickness during the process of forming the second electrode. Alternatively, the aluminum oxide layer can be formed by introducing oxygen to oxidize the aluminum layer after forming the aluminum layer on the surface of the second electrode after forming the second electrode.

[0055] Optionally, the oxygen content of the at least one aluminum oxide layer 50 is a constant value; or the oxygen content of the at least one aluminum oxide layer 50 gradually increases in the direction away from the second electrode 40; or the organic light emitting diode structure comprises at least two aluminum oxide layers 50, and the oxygen content of the aluminum oxide layer 50 farthest from the second electrode 40 gradually increases in the direction away from the second electrode 40, and the oxygen content of the other aluminum oxide layers 50 first increases and then decreases.

[0056] Specifically, oxygen can be introduced during the process of evaporating aluminum or after evaporating the aluminum layer. If the amount of oxygen introduced is constant, the aluminum oxide layer 50 with a constant oxygen content can be formed. If oxygen is introduced during the process of evaporating aluminum, and the amount of oxygen introduced during the process of evaporating aluminum gradually increases, the aluminum oxide layer 50 with gradually increasing oxygen content can be formed. If the amount of oxygen introduced during the process of evaporating aluminum first increases and then decreases, the aluminum oxide layer 50 with oxygen content first increasing and then decreasing can be formed.

[0057] The oxygen content of the at least one aluminum oxide layer 50 gradually increases, the oxygen content of the at least one aluminum oxide layer 50 linearly increases, or the oxygen content of the at least one aluminum oxide layer 50 gradually increases in a gradient manner, or the oxygen content of part of the film layers linearly increases, or the oxygen content of part of the film layers gradually increases in a gradient manner, which is not specifically limited in the embodiment. For example, the organic light-emitting diode structure includes two aluminum oxide layers 50, the oxygen content of the first aluminum oxide layer 50 linearly increases, the oxygen content of the second aluminum oxide layer 50 is constant, and the oxygen content of the second aluminum oxide layer 50 is greater than the oxygen content of the first aluminum oxide layer 50.

[0058] When the oxygen content of the at least one aluminum oxide layer 50 is constant, the manufacturing process of the aluminum oxide layer 50 is relatively simple.

[0059] Since the lower the oxygen content of the aluminum oxide layer 50, the stronger the adhesion between the aluminum oxide layer 50 and the second electrode 40, and the better the interface water-oxygen blocking performance, the higher the oxygen content of the aluminum oxide layer 50, the better the insulation and water blocking performance, the oxygen content of the at least one aluminum oxide layer 50 gradually increases in a direction away from the second electrode 40, the aluminum oxide layer 50 can better protect the second electrode 40 and the light-emitting layer 30 while ensuring that the aluminum oxide layer 50 has good water blocking and insulation performance, and the adhesion between the aluminum oxide layer 50 and the second electrode 40 can be improved, the interface water-oxygen blocking performance between the second electrode 40 and the aluminum oxide layer 50 can be improved, and the reliability of the organic light-emitting diode structure can be improved.

[0060] In addition, when the oxygen content of the aluminum oxide layer 50 is low, the adhesion between the adjacent two aluminum oxide layers 50 is strong, by setting that the organic light-emitting diode structure includes at least two aluminum oxide layers 50, the oxygen content of the aluminum oxide layer 50 farthest from the second electrode 40 gradually increases in a direction away from the second electrode 40, and the oxygen content of the other aluminum oxide layers 50 first increases and then decreases, the aluminum oxide layer 50 closest to the second electrode 40 has good adhesion with the second electrode 40, and the adjacent aluminum oxide layers 50 have good adhesion, the interface water-oxygen blocking performance between the adjacent two film layers is improved, and each aluminum oxide layer 50 has good water blocking and insulation performance, which can better protect the second electrode 40 and the light-emitting layer 30, better block water vapor from entering, and improve the packaging reliability of the organic light-emitting structure.

[0061] It should be noted that when the organic light-emitting diode structure includes at least two aluminum oxide layers 50, the oxygen content of the aluminum oxide layer 50 farthest from the second electrode 40 gradually increases in a direction away from the second electrode 40, and the oxygen content of the other aluminum oxide layers 50 first increases and then decreases, the oxygen content of the aluminum oxide at the adjacent interface of the adjacent two aluminum oxide layers 50 can be the same, for example Figure 2 is another schematic diagram of an organic light-emitting diode structure provided by Embodiment One of the present application, which is described with reference to Figure 2The OLED structure includes two aluminum oxide layers 50, i.e. a first aluminum oxide layer 51 and a second aluminum oxide layer 52. The oxygen content of the first aluminum oxide layer 51 increases from a to b and then decreases from b to c in the direction away from the second electrode 40. The oxygen content of the second aluminum oxide layer 52 increases from c to d in the direction away from the second electrode 40, where a, b, c and d are positive numbers. The oxygen content of the aluminum oxide at the interface between the first aluminum oxide layer 51 and the second aluminum oxide layer 52 is c, and the adhesion between the two layers is better.

[0062] Optionally, when the oxygen content of at least one aluminum oxide layer 50 gradually increases in the direction away from the second electrode 40: the oxygen content of each aluminum oxide layer 50 linearly increases in the direction away from the second electrode 40; or, referring to Figure 2 The OLED structure includes at least two aluminum oxide layers 50, and the oxygen content of the at least two aluminum oxide layers 50 increases in the direction away from the second electrode 40.

[0063] Wherein, referring to Figure 1 The OLED structure can include one aluminum oxide layer 50, and the oxygen content of the aluminum oxide layer 50 linearly increases in the direction from the second electrode 40 to the thin film encapsulation layer 60. In addition, the OLED structure can also include two or more aluminum oxide layers 50, and the oxygen content of each aluminum oxide layer 50 linearly increases. The amount of oxygen introduced during the process of evaporating aluminum on the surface of the second electrode 40 linearly increases, forming an aluminum oxide layer 50 with linearly increasing oxygen content.

[0064] In addition, referring to Figure 2 The oxygen content of the at least two aluminum oxide layers 50 increases in the direction away from the second electrode 40. Specifically, the oxygen content of each aluminum oxide layer 50 can remain unchanged, and the oxygen content of each aluminum oxide layer 50 gradually increases in the direction away from the second electrode 40. Specifically, the amount of oxygen introduced during the process of evaporating aluminum can be adjusted to increase the amount of oxygen introduced, forming at least two aluminum oxide layers 50 with increasing oxygen content.

[0065] For example, referring to Figure 2 The OLED structure can include a first aluminum oxide layer 51 and a second aluminum oxide layer 52. The oxygen content of the first aluminum oxide layer 51 is a first constant value, and the oxygen content of the second aluminum oxide layer 52 is a second constant value, which is greater than the first constant value.

[0066] When forming an aluminum oxide layer 50 with linearly increasing oxygen content, or forming at least two aluminum oxide layers 50 with increasing oxygen content, the oxygen content of the aluminum oxide layer 50 adjacent to the second electrode 40 is relatively low, which allows the aluminum oxide layer 50 and the second electrode 40 to have good adhesion. In addition, when forming an aluminum oxide layer 50 with linearly increasing or increasing oxygen content, the adjustment process of the amount of oxygen during the manufacturing process is relatively simple, and the manufacturing process is relatively easy.

[0067] Optionally, Figure 3 is a schematic diagram of still another organic light emitting diode structure provided by Embodiment One of the present application, referring to Figure 3 The light emitting layer 30 comprises a first surface 31 and a second surface 32 connected to each other, the first surface 31 is the surface of the light emitting layer 30 away from the substrate 10, and the second surface 32 surrounds the first surface 31; the second electrode 40 comprises a first part 41 and a second part 42 connected to each other; the first part 41 is arranged on the first surface 31, and the second part 42 is arranged on the second surface 32; and the aluminum oxide layer 50 covers the surfaces of the first part 41 and the second part 42.

[0068] The second surface 32 is the side surface of the light emitting layer 30, the second part 42 covers the side surface of the light emitting layer 30, and the aluminum oxide layer 50 covers the surfaces of the first part 41 and the second part 42, so that the upper surface and the side surface of the entire light emitting layer 30 are covered by the second electrode 40 and the aluminum oxide layer 50. Since the aluminum oxide layer 50 has insulation and good water vapor blocking properties, by arranging the aluminum oxide layer 50 on the surfaces of the first part 41 and the second part 42 of the second electrode 40, the damage to the second electrode 40 and the light emitting layer 30 during the manufacturing process of the thin film encapsulation layer 60 can be further avoided, and the aluminum oxide layer 50 can also block the water vapor from entering, thereby improving the interface encapsulation effect and the side surface encapsulation effect of the organic light emitting structure.

[0069] Optionally, Figure 4 is a schematic diagram of still another organic light emitting diode structure provided by Embodiment One of the present application, referring to Figure 4 The surface of the second part 42 is provided with at least two layers of aluminum oxide layers 50, and the oxygen content of the at least two layers of aluminum oxide layers 50 increases in the direction away from the second electrode 40, or referring to Figure 3 The oxygen content of the aluminum oxide layer 50 on the surface of the second part 42 linearly increases.

[0070] In this way, the side surface encapsulation effect can be further improved, and the adhesion between the aluminum oxide layer 50 and the second electrode 40 can be ensured.

[0071] Specifically, the first part 41 and the second part 42 can be provided with one, two or more layers of the aluminum oxide layer 50. The first part 41 and the second part 42 can be provided with the same or different aluminum oxide layer 50. The first part 41 and the second part 42 can be provided with the same or different number of layers, oxygen content and thickness of the aluminum oxide layer 50.

[0072] For example, referring to FIG. 1, the first part 41 is provided with one layer of the fourth aluminum oxide layer 54, and the second part 42 is provided with two layers of the third aluminum oxide layer 53. The two layers of the third aluminum oxide layer 53 have a gradient increase in oxygen content, and the fourth aluminum oxide layer 54 has a constant oxygen content. Figure 4

[0073] Optionally, the total thickness of the at least one layer of the aluminum oxide layer is greater than or equal to 5 nm.

[0074] When the total thickness of the aluminum oxide layer is less than 5 nm, the water resistance of the aluminum oxide layer is insufficient, and the preparation process is difficult. Therefore, the total thickness of the at least one layer of the aluminum oxide layer is greater than or equal to 5 nm, so that the aluminum oxide layer has good insulation and water resistance, and the process is relatively simple.

[0075] Optionally, the organic light-emitting diode structure further comprises a water-oxygen barrier layer 80, which is arranged between the substrate 10 and the first electrode 20.

[0076] The material of the water-oxygen barrier layer 80 includes any one or a combination of at least two of silicon nitride, silicon oxide, silicon oxynitride, epoxy resin or polyolefin. The preparation method of the water-oxygen barrier layer 80 can be one or a combination of at least two of atomic layer deposition (ALD), plasma enhanced chemical vapor deposition (PECVD), inkjet printing technology (IJP), screen printing or sputtering. The water-oxygen barrier layer 80 has a water and oxygen blocking function, which prevents water and oxygen from entering the inside of the organic light-emitting diode structure from the substrate 10, and improves the service life of the organic light-emitting diode structure.

[0077] Embodiment two

[0078] The embodiment of the present application provides a preparation method of an organic light-emitting diode based on the above-mentioned embodiments.​Figure 5 is a flow chart of a preparation method of an organic light emitting diode provided by Embodiment Two of the present application, referring to Figure 5 The method comprises the following steps:

[0079] Step 110: disposing a first electrode on a surface of a substrate.

[0080] Step 120: disposing a light emitting layer on the first electrode.

[0081] Step 130: disposing a second electrode on the light emitting layer.

[0082] Step 140: disposing at least one aluminum oxide layer on the second electrode; wherein the aluminum oxide layer covers at least a preset surface of the second electrode, and the preset surface is a surface of the second electrode away from the surface of the substrate in a thickness direction of the substrate.

[0083] When the second electrode is made of aluminum or aluminum-silver material, at least one aluminum oxide layer can be formed on the surface of the second electrode after an aluminum or aluminum-silver alloy layer of a certain thickness is prepared. Alternatively, an aluminum layer can be prepared on the surface of the second electrode after the second electrode is formed, and the aluminum oxide layer can be formed by processing the aluminum layer.

[0084] Step 150: disposing a thin film encapsulation layer on the aluminum oxide layer.

[0085] The thin film encapsulation layer with high water and oxygen resistance can be prepared by plasma enhanced chemical vapor deposition.

[0086] The preparation method of the organic light emitting diode provided by the technical scheme of the present application sets at least one aluminum oxide layer between the second electrode and the thin film encapsulation layer. Since the aluminum oxide layer has insulation and good water vapor resistance, the aluminum oxide layer set on the second electrode can not only avoid damage to the second electrode and the light emitting layer during the preparation of the thin film encapsulation layer, but also block water vapor from entering, thereby improving the encapsulation reliability of the organic light emitting structure.

[0087] Optionally, disposing at least one aluminum oxide layer on the second electrode comprises: preparing the at least one aluminum oxide layer by using the equipment for preparing the thin film encapsulation layer.

[0088] The aluminum layer on the surface of the second electrode can be processed by introducing laughing gas, oxygen, a mixture of laughing gas and oxygen, a mixture of laughing gas and hydrogen, a mixture of oxygen and hydrogen, or a mixture of laughing gas, oxygen and hydrogen into the plasma enhanced chemical vapor deposition process equipment before the thin film encapsulation layer is prepared by the plasma enhanced chemical vapor deposition process equipment, so as to form the aluminum oxide layer, and then the material required for preparing the thin film encapsulation layer is introduced to prepare the thin film encapsulation layer.

[0089] The embodiment adopts the equipment used for preparing the thin film encapsulation layer to prepare the at least one aluminum oxide layer, without adding new process and equipment for the aluminum oxide layer, thereby reducing the process cost.

[0090] Optionally, the at least one aluminum oxide layer on the second electrode is prepared by: introducing oxygen during the process of evaporating aluminum on the surface of the second electrode to form the aluminum oxide layer; or introducing oxygen during the process of evaporating aluminum on the surface of the second electrode, and linearly increasing the amount of oxygen introduced to form the aluminum oxide layer with linearly increased oxygen content in the direction away from the second electrode; or introducing oxygen during the process of evaporating aluminum on the surface of the second electrode, and linearly increasing the amount of oxygen introduced in a gradient to form the at least two aluminum oxide layers with gradiently increased oxygen content in the direction away from the second electrode; or evaporating at least one aluminum layer on the surface of the second electrode, and treating the aluminum layer by the plasma enhanced chemical vapor deposition process or the plasma treatment process after evaporating each aluminum layer to form the aluminum oxide layer.

[0091] In the process, a fixed amount of oxygen is introduced after evaporating aluminum on the surface of the second electrode to form the aluminum oxide layer with fixed oxygen content, and the process is relatively simple.

[0092] In the process of evaporating aluminum on the surface of the second electrode, the amount of oxygen introduced linearly increases with time, and the aluminum oxide layer with linearly increased oxygen content can be formed. The speed of linearly increasing the amount of oxygen can be adjusted according to the change of oxygen content of the aluminum oxide layer.

[0093] In the process of evaporating aluminum on the surface of the second electrode, a fixed amount of oxygen is introduced in each time period to form one aluminum oxide layer with fixed oxygen content in each time period. In adjacent time periods, the amount of oxygen introduced in the later time period is greater than that in the former time period, and the at least two aluminum oxide layers with gradiently increased oxygen content can be formed.

[0094] When the aluminum oxide layer is formed by the plasma enhanced chemical vapor deposition process or the plasma treatment process, the gas containing laughing gas and / or oxygen can be introduced into the manufacturing chamber to form oxygen ions to treat the aluminum layer and form the aluminum oxide layer. Since the combination speed of oxygen ions and aluminum is faster, the aluminum layer can be treated by the plasma enhanced chemical vapor deposition process or the plasma treatment process to form the aluminum oxide layer faster, thereby shortening the process time.

[0095] In addition, the introduction of hydrogen can reduce the power required for the oxidizing gas to form plasma, thereby preventing damage to the second electrode.

[0096] Specifically, refer to Figure 1When the material of the second electrode 40 includes aluminum or aluminum-silver alloy, the second electrode can be prepared together with the aluminum oxide layer. Specifically, after forming an aluminum or aluminum-silver alloy layer with a certain thickness, the aluminum or aluminum-silver alloy layer can be oxidized by introducing oxygen to form the second electrode 40 and the aluminum oxide layer 50. Alternatively, after forming an aluminum or aluminum-silver alloy layer with a certain thickness, the aluminum or aluminum-silver alloy layer can be treated by a plasma enhanced chemical vapor deposition process or a plasma treatment process to form the aluminum oxide layer 50. Alternatively, after forming an aluminum or aluminum-silver alloy layer with a certain thickness, aluminum can be continuously evaporated, and in the process of evaporating the aluminum, the aluminum can be oxidized by introducing oxygen to form the aluminum oxide layer 50.

[0097] In addition, if a two-layer or multi-layer aluminum oxide layer is to be formed, the aluminum can be continuously evaporated to form the aluminum oxide layer.

[0098] It should be understood that the various forms of the flow shown above can be reordered, added to, or deleted from without departing from the scope of the present application. For example, the steps recited in the present application can be performed in parallel, in series, or in a different order, and the present application is not limited herein as long as the desired results of the technical solutions of the present application can be achieved.

[0099] The specific embodiments described above do not constitute an limitation on the protection scope of the present application. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An organic light emitting diode structure, characterized in that, The organic light emitting diode structure comprises: a substrate, a first electrode, a light emitting layer, a second electrode and a thin film encapsulation layer which are sequentially stacked; at least one aluminum oxide layer is arranged between the second electrode and the thin film encapsulation layer, wherein the aluminum oxide layer covers at least a preset surface of the second electrode, the preset surface is a surface of the second electrode away from the substrate along a thickness direction of the substrate; an oxygen content of the at least one aluminum oxide layer gradually increases along a direction away from the second electrode; alternatively, the organic light emitting diode structure comprises at least two aluminum oxide layers, an oxygen content of the aluminum oxide layer farthest from the second electrode gradually increases along a direction away from the second electrode, and oxygen contents of the other aluminum oxide layers first increase and then decrease; a material of the second electrode comprises aluminum or aluminum-silver alloy.

2. The organic light emitting diode structure of claim 1, wherein: when the oxygen content of the at least one aluminum oxide layer gradually increases along the direction away from the second electrode: the oxygen content of each aluminum oxide layer linearly increases along the direction away from the second electrode; or the organic light emitting diode structure comprises at least two aluminum oxide layers, and oxygen contents of the at least two aluminum oxide layers gradually increase along the direction away from the second electrode.

3. The organic light emitting diode structure of claim 1, wherein: the light emitting layer comprises a first surface and a second surface connected to each other, the first surface is a surface of the light emitting layer away from the substrate, and the second surface surrounds the first surface; the second electrode comprises a first part and a second part connected to each other; the first part is arranged on the first surface, and the second part is arranged on the second surface; the aluminum oxide layer covers surfaces of the first part and the second part.

4. The organic light emitting diode structure of claim 1, wherein: a total thickness of the at least one aluminum oxide layer is greater than or equal to 5 nm.

5. The organic light emitting diode structure of claim 1, wherein, further comprising: a water and oxygen barrier layer arranged between the substrate and the first electrode.

6. A method of manufacturing an organic light emitting diode, characterized by, The method comprises: arranging a first electrode on a surface of a substrate; arranging a light emitting layer on the first electrode; arranging a second electrode on the light emitting layer; arranging at least one aluminum oxide layer on the second electrode; wherein the aluminum oxide layer covers at least a preset surface of the second electrode, the preset surface is a surface of the second electrode away from the substrate along a thickness direction of the substrate; arranging a thin film encapsulation layer on the aluminum oxide layer; an oxygen content of the at least one aluminum oxide layer gradually increases along a direction away from the second electrode; alternatively, the organic light emitting diode structure comprises at least two aluminum oxide layers, an oxygen content of the aluminum oxide layer farthest from the second electrode gradually increases along a direction away from the second electrode, and oxygen contents of the other aluminum oxide layers first increase and then decrease; a material of the second electrode comprises aluminum or aluminum-silver alloy.

7. The production method according to claim 6, wherein arranging at least one aluminum oxide layer on the second electrode comprises: using a device for preparing the thin film encapsulation layer to prepare the at least one aluminum oxide layer.

8. The preparation method according to claim 6, characterized in that forming at least one aluminum layer on the surface of the second electrode; forming the aluminum layer by evaporating aluminum on the surface of the second electrode, and introducing oxygen during or after the evaporation of the aluminum; or, introducing oxygen during the evaporation of the aluminum on the surface of the second electrode, and linearly increasing the amount of the introduced oxygen, to form an aluminum oxide layer with linearly increased oxygen content in a direction away from the second electrode; or, introducing oxygen during the evaporation of the aluminum on the surface of the second electrode, and gradiently increasing the amount of the introduced oxygen, to form at least two aluminum oxide layers with gradiently increased oxygen content in a direction away from the second electrode; or, forming at least one aluminum layer on the surface of the second electrode, and treating the aluminum layer by a plasma enhanced chemical vapor deposition process or a plasma treatment process after the evaporation of each aluminum layer to form an aluminum oxide layer.

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