Organic light emitting device and display panel thereof

Abstract

The application provides an organic light-emitting device and a display panel thereof. The organic light-emitting device comprises a light-emitting layer and an electron blocking layer and a hole blocking layer located on opposite sides of the light-emitting layer; wherein the light-emitting layer is composed of a host material, a guest material and a co-doping agent; and the absolute value of the highest occupied molecular orbital energy level of the co-doping agent is between the absolute value of the highest occupied molecular orbital energy level of the electron blocking layer and the absolute value of the highest occupied molecular orbital energy level of the host material. Specifically, by setting the absolute value of the highest occupied molecular orbital energy level of the co-doping agent in the light-emitting layer between the absolute value of the highest occupied molecular orbital energy level of the electron blocking layer and the absolute value of the highest occupied molecular orbital energy level of the host material, the co-doping agent can assist the hole to enter the light-emitting layer as a hole transmission ladder and capture part of the hole, thereby reducing the accumulation of holes at the interface between the electron blocking layer and the light-emitting layer, reducing the capacitance of the organic light-emitting device, and further improving the problem of ghosting color cast.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to an organic light-emitting device and its display panel. Background Technology

[0002] Organic light-emitting diodes (OLEDs) have advantages such as high response speed, high color purity, and flexibility, and therefore have been widely used in the display field.

[0003] In the existing technology, due to the different capacitance (CV) values ​​of the R / G / B devices, the larger CV charges more slowly and has a lower proportion in the first frame; while the smaller CV charges more quickly and has a higher proportion in the first frame. Therefore, the difference in the proportion of the first frame of the R / G / B devices during the lighting process leads to the ghosting and color distortion. Summary of the Invention

[0004] This application provides an organic light-emitting device and its display panel, which can improve the problems of ghosting and color distortion.

[0005] To solve the above-mentioned technical problems, the first technical solution provided in this application is: to provide an organic light-emitting device, the organic light-emitting device including a light-emitting layer and an electron blocking layer and a hole blocking layer located on opposite sides of the light-emitting layer;

[0006] The light-emitting layer is composed of a host material, a guest material, and a co-doperb; and the absolute value of the highest occupied molecular orbital energy level of the co-doperb is located between the absolute value of the highest occupied molecular orbital energy level of the electron blocking layer and the absolute value of the highest occupied molecular orbital energy level of the host material.

[0007] In one embodiment, the absolute value of the highest occupied molecular orbital energy level of the co-doperant is located between the absolute value of the highest occupied molecular orbital energy level of the guest material and the absolute value of the highest occupied molecular orbital energy level of the host material.

[0008] Furthermore, the absolute value of the highest occupied molecular orbital energy level of the guest material is greater than the absolute value of the highest occupied molecular orbital energy level of the electron blocking layer.

[0009] In one embodiment, the absolute value of the lowest unoccupied molecular orbital energy level of the co-doperant is less than the absolute value of the lowest unoccupied molecular orbital energy level of the host material and less than the absolute value of the lowest unoccupied molecular orbital energy level of the guest material.

[0010] In one embodiment, the absolute value of the lowest unoccupied molecular orbital energy level of the host and guest materials and the co-doper is greater than the absolute value of the lowest unoccupied molecular orbital energy level of the electron blocking layer; and the absolute value of the highest occupied molecular orbital energy level of the host and guest materials and the co-doper is less than the absolute value of the highest occupied molecular orbital energy level of the hole blocking layer.

[0011] In one embodiment, the absolute value of the triplet energy level of the co-doper is greater than the absolute value of the triplet energy level of the host material.

[0012] In one embodiment, the doping ratio of the co-dopermeable is 0.4 wt% to 1 wt%.

[0013] In one embodiment, the doping ratio of the guest material is 5wt%-12wt%.

[0014] In one embodiment, the co-doperic agent and the guest material are uniformly distributed in the luminescent layer.

[0015] In one embodiment, the organic light-emitting device further includes:

[0016] A hole transport layer is disposed on the side of the electron blocking layer opposite to the light-emitting layer;

[0017] A hole injection layer is disposed on the side of the hole transport layer opposite to the light-emitting layer;

[0018] An electron transport layer is positioned on the side of the hole blocking layer opposite to the light-emitting layer.

[0019] An electron injection layer is placed on the side of the electron transport layer opposite to the light-emitting layer.

[0020] To solve the above-mentioned technical problems, the first technical solution provided by this application is: to provide a display panel, wherein the display panel includes the organic light-emitting device described in any of the above-mentioned claims.

[0021] The beneficial effects of this application, unlike the prior art, are as follows: the organic light-emitting device and its display panel provided in this application include an emitting layer and an electron blocking layer and a hole blocking layer located on opposite sides of the emitting layer; wherein, the emitting layer is composed of a host material, a guest material, and a co-doperb; and the absolute value of the highest occupied molecular orbital energy level of the co-doperb is located between the absolute value of the highest occupied molecular orbital energy level of the electron blocking layer and the absolute value of the highest occupied molecular orbital energy level of the host material. Specifically, by setting the absolute value of the highest occupied molecular orbital energy level of the co-doperb in the emitting layer to be located between the absolute value of the highest occupied molecular orbital energy level of the electron blocking layer and the absolute value of the highest occupied molecular orbital energy level of the host material, the co-doperb can act as a hole transport ladder to assist holes in entering the emitting layer and trapping some holes, thereby reducing the amount of holes accumulated at the interface between the electron blocking layer and the emitting layer, reducing the capacitance of the organic light-emitting device, and thus improving the problem of ghosting and color distortion. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0023] Figure 1 A partial structural schematic diagram of an embodiment of the organic light-emitting device provided in this application;

[0024] Figure 2 for Figure 1 The diagram shows the energy levels of an organic light-emitting device.

[0025] Figure 3 A partial structural schematic diagram of another embodiment of the organic light-emitting device provided in this application;

[0026] Figure 4 for Figure 3 The diagram shows the energy levels of an organic light-emitting device.

[0027] Figure 5 A schematic diagram of the structure of an embodiment of the display panel provided in this application;

[0028] Figure 6 A partial structural schematic diagram of an embodiment of the display panel provided in this application;

[0029] Figure 7 This is a schematic diagram of the film layer structure of an embodiment of the display panel provided in this application. Detailed Implementation

[0030] The terms "first," "second," and "third" in this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationships and movements between components in a specific orientation (as shown in the figures). If the specific orientation changes, the directional indications also change accordingly. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0031] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0032] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0033] See Figure 1 and Figure 2 , Figure 1 A partial structural schematic diagram of an embodiment of the organic light-emitting device provided in this application; Figure 2 for Figure 1 The diagram shows the energy levels of an organic light-emitting device.

[0034] This application provides an organic light-emitting device, which includes a light-emitting layer 10 and an electron blocking layer 20 and a hole blocking layer 30 located on opposite sides of the light-emitting layer 10.

[0035] The electron blocking layer 20 prevents electrons from being directly injected from the cathode of the display panel into the hole transport layer 40, thereby reducing the outward expansion of the effective recombination area of ​​electron-hole pairs, avoiding unnecessary current leakage at the edge of the device or in the non-light-emitting area, and improving luminous efficiency and color purity.

[0036] The hole blocking layer 30 is positioned and functions opposite to the electron blocking layer 20. The hole blocking layer 30 prevents holes from diffusing from the anode side of the display panel to the electron transport layer 60, and prevents holes and electrons from recombinating prematurely in the non-light-emitting area, thereby improving the luminous efficiency and color stability of the device.

[0037] Among them, the light-emitting layer 10 is "G-EML (Green-EML)". Compared with EML that simply uses self-luminous small molecules or polymers, G-EML takes advantage of the guest-host doping system, which improves the stability of doping concentration, enhances light extraction efficiency, and improves device lifespan.

[0038] In this embodiment, compared with the prior art where the light-emitting layer 10 includes a host material GH and a guest material GD, the light-emitting layer 10 also includes a co-doper CD. That is, the light-emitting layer 10 is composed of the host material GH, the guest material GD and the co-doper CD. The absolute value of the highest occupied molecular orbital energy level (i.e., HOMO energy level) of the co-doper CD is located between the absolute value of the highest occupied molecular orbital energy level of the electron blocking layer 20 and the absolute value of the highest occupied molecular orbital energy level of the host material GH.

[0039] Specifically, by setting the absolute value of the highest occupied molecular orbital energy level of the co-doper CD in the light-emitting layer 10 to be between the absolute value of the highest occupied molecular orbital energy level of the electron blocking layer 20 and the absolute value of the highest occupied molecular orbital energy level of the host material GH, specifically, the absolute value of the highest occupied molecular orbital energy level of the co-doper CD is greater than the absolute value of the highest occupied molecular orbital energy level of the electron blocking layer 20 and less than the absolute value of the highest occupied molecular orbital energy level of the host material GH, the co-doper CD can act as a hole transport ladder to assist holes in entering the light-emitting layer 10 and trapping some holes, thereby reducing the amount of holes accumulated at the interface between the electron blocking layer 20 and the light-emitting layer 10, reducing the capacitance of the organic light-emitting device, and thus improving the problem of ghosting and color distortion.

[0040] Taking existing organic light-emitting devices (OLEDs) as examples, which are categorized into red, green, and blue OLEDs, the capacitances of these three types of OLEDs differ. Red and blue OLEDs have smaller capacitances, resulting in faster charging and a higher frame rate. In contrast, green OLEDs have larger capacitances, leading to slower charging and a lower frame rate. Consequently, the first frame percentage varies depending on the color of the OLED. Specifically, in the first frame, the brightness of green OLEDs is lower than in a stable frame, while the brightness of red and blue OLEDs is relatively higher. This results in a reddish tint to the first frame. Consequently, when dragging low-grayscale images, the subjective visual effect appears reddish, which is highly perceptible to the human eye but results in a poor subjective visual effect, a phenomenon known as motion blur or color cast.

[0041] To address the aforementioned issues, this application further incorporates a co-dopericylase CD into the emitting layer 10, for example, in the emitting layer 10 of a green organic light-emitting device. This co-dopericylase CD can act as a hole transport ladder in the green organic light-emitting device, assisting holes in entering the emitting layer 10 and capturing some holes. This reduces the amount of holes accumulated at the interface between the electron blocking layer 20 and the emitting layer 10, thereby reducing the capacitance of the green organic light-emitting device. Consequently, the capacitance difference among the red, green, and blue organic light-emitting devices is reduced, thus improving the luminous uniformity of the red, green, and blue organic light-emitting devices in the first frame and mitigating the problem of motion blur and color distortion.

[0042] In other embodiments, co-dopericylase CD can be added to the light-emitting layer 10 of the red, green and blue organic light-emitting devices. By adjusting the doping ratio of co-dopericylase CD in the light-emitting layers 10 of different colors, the capacitance of the organic light-emitting devices of different colors can be made to be basically the same, thereby avoiding the problem of different proportions of the first frame during the lighting process of the organic light-emitting devices of different colors, which would lead to ghosting and color distortion.

[0043] For ease of description, the embodiments of this application use green organic light-emitting devices as an example.

[0044] Please continue reading Figure 2In one embodiment, in the light-emitting layer 10, the absolute value of the highest occupied molecular orbital energy level of the co-doperant CD is located between the absolute value of the highest occupied molecular orbital energy level of the guest material GD and the absolute value of the highest occupied molecular orbital energy level of the host material GH. Specifically, the absolute value of the highest occupied molecular orbital energy level of the co-doperant CD is less than the absolute value of the highest occupied molecular orbital energy level of the host material GH, but greater than the absolute value of the highest occupied molecular orbital energy level of the guest material GD, and the absolute value of the highest occupied molecular orbital energy level of the guest material GD is greater than the absolute value of the highest occupied molecular orbital energy level of the electron blocking layer 20. Thus, the co-doperant can trap a small number of holes without excessively trapping them, and will not affect the recombination of holes with electrons within the light-emitting layer.

[0045] Please continue reading Figure 2 In one embodiment, the absolute value of the lowest unoccupied molecular orbital (LUMO) energy level of the co-doper CD is less than the absolute value of the lowest unoccupied molecular orbital (LUMO) energy level of the host material GH, and less than the absolute value of the lowest unoccupied molecular orbital (LUMO) energy level of the guest material GD. Specifically, by setting the absolute value of the lowest unoccupied molecular orbital (LUMO) energy level of the co-doper CD to be less than the absolute value of the lowest unoccupied molecular orbital (LUMO) energy level of the host material GH, and simultaneously less than the absolute value of the lowest unoccupied molecular orbital (LUMO) energy level of the guest material GD, electrons can be prevented from being captured by the co-doper CD, thus avoiding affecting the electron capture of the host and guest materials, and consequently avoiding affecting the device efficiency.

[0046] Please continue reading Figure 2 In one embodiment, the absolute values ​​of the lowest unoccupied molecular orbital energy levels of the host, guest, and co-doperic materials CD are greater than the absolute values ​​of the lowest unoccupied molecular orbital energy levels of the electron blocking layer 20; and the absolute values ​​of the highest occupied molecular orbital energy levels of the host, guest, and co-doperic materials are less than the absolute values ​​of the highest occupied molecular orbital energy levels of the hole blocking layer 30. This confines electrons and holes within the luminescent layer, increasing the probability of electron-hole recombination.

[0047] Furthermore, in one embodiment, the absolute value of the triplet energy level of the co-doper CD is greater than the absolute value of the triplet energy level of the host material GH. This prevents energy from being transferred from the host material GH to the co-doper CD, thus affecting the process of energy transfer from the host material GH to the guest material GD, which would lead to a deterioration in device efficiency.

[0048] In the above embodiments, the host material GH is used to support the guest material GD and assist it in luminescence. The selection of the host material GH directly affects the key performance characteristics of the device, such as luminous efficiency, color purity, and operating life. Specifically, the types of host material GH include, but are not limited to, aromatic amine compounds; carbazole derivatives; fluorene compounds; pyridine, pyrazoline, and oxadiazole derivatives; and fused-ring aromatic compounds. In the embodiments of this application, the types of host material GH include, but are not limited to, one or more of mCBPP (3,3'-bis(9H-carbazole-9-yl)-1,1'-biphenyl), mCP (9,9'-biscarbazole-3,5-diphenyl), TCTA (4,4',4”-tris(carbazole-9-yl)triphenylamine), DMQA (N,N'-dimethylquinacridone), and TPA (tri-n-propylamine).

[0049] In this process, guest materials (GDs) play a crucial role in luminescence. They are doped into the host material (GH) to modulate and enhance the luminescence characteristics of the device. Specifically, guest materials (GDs) include fluorescent or phosphorescent materials. In the embodiments of this application, the types of guest materials (GDs) include, but are not limited to, one or more of 4CzIPNN (2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile), 4CzTPN (2,3,5,6-tetrakis(9-carbazolyl)-terephthalonitrile), TADF (thermally excited delayed fluorescence), ADN (9,10-bis(1-naphthyl)anthracene), and DPVBi (4,4'-bis(2,2-stilbene)-1,1'-biphenyl).

[0050] The co-doper CD can be selected from one or more of the host material GH or the guest material GD, as long as the absolute value of the highest occupied molecular orbital energy level of the co-doper CD is located between the absolute value of the highest occupied molecular orbital energy level of the electron blocking layer 20 and the absolute value of the highest occupied molecular orbital energy level of the host material GH. As a hole transport ladder, it assists holes in entering the light-emitting layer 10 and captures some holes, thereby reducing the amount of holes accumulated at the interface between the electron blocking layer 20 and the light-emitting layer 10 and reducing the capacitance of the organic light-emitting device. There are no restrictions on this.

[0051] In one embodiment, the doping ratio of the co-doper cyanide (CD) is 0.4 wt% to 1 wt%. For example, the doping ratio of the CD can be 0.4 wt%, 0.6 wt%, 0.8 wt%, or 1 wt%. It is understood that the doping ratio of the CD is related to reducing the capacitance of the organic light-emitting device (OLED). In this application, as long as the specific doping ratio of the CD can reduce the capacitance of the OLED using the CD, thereby making the capacitance of OLEDs of different colors substantially the same, it is not limited here.

[0052] Furthermore, in this embodiment, the co-dopericylant CD and the guest material GD are uniformly distributed in the light-emitting layer 10 to avoid affecting the luminous efficiency of the device.

[0053] Specifically, experiments have shown that if the doping concentrations of co-doperamide (CD) and guest material (GD) in the light-emitting layer 10 are not uniform, although hole injection will be improved to some extent, the luminous efficiency of the device will also be reduced.

[0054] In one embodiment, the doping ratio of the guest material GD is 5 wt%-12 wt%. For example, the doping ratio of the guest material GD can be 5 wt%, 7 wt%, 9 wt%, or 12 wt%. Specifically, the doping ratio of the guest material GD is related to the type of guest material GD. In some high-efficiency phosphorescent organic light-emitting devices, a lower doping ratio of the guest material GD is often used to reduce self-quenching effects while ensuring efficient utilization of triplet excitons. For some fluorescent organic light-emitting devices, the doping ratio of the guest material GD may be higher because there is spin statistical confinement in the fluorescence process, requiring more luminescent centers to improve quantum efficiency.

[0055] Specifically, the organic light-emitting device provided in this application, by setting the absolute value of the highest occupied molecular orbital energy level of the co-doperic (CD) in the light-emitting layer 10 to be between the absolute value of the highest occupied molecular orbital energy level of the electron blocking layer 20 and the absolute value of the highest occupied molecular orbital energy level of the host material GH, allows the co-doperic (CD) to act as a hole transport ladder to assist holes in entering the light-emitting layer 10 and trapping some holes, thereby reducing the amount of holes accumulated at the interface between the electron blocking layer 20 and the light-emitting layer 10, reducing the capacitance of the organic light-emitting device, and thus improving the problem of ghosting and color distortion.

[0056] See Figure 3 and Figure 4 , Figure 3 A partial structural schematic diagram of another embodiment of the organic light-emitting device provided in this application; Figure 4 for Figure 3 The diagram shows the energy levels of an organic light-emitting device.

[0057] In some embodiments, the organic light-emitting device further includes a hole transport layer 40, a hole injection layer 50, an electron transport layer 60, and an electron injection layer 70.

[0058] The hole transport layer 40 is disposed on the side of the electron blocking layer 20 away from the light-emitting layer 10; the hole injection layer 50 is disposed on the side of the hole transport layer 40 away from the light-emitting layer 10; the electron transport layer 60 is disposed on the side of the hole blocking layer 30 away from the light-emitting layer 10; and the electron injection layer 70 is disposed on the side of the electron transport layer 60 away from the light-emitting layer 10.

[0059] Among them, the absolute values ​​of the highest occupied molecular orbital energy levels of hole injection layer 50, hole transport layer 40, electron blocking layer 20, luminescent layer 10, hole blocking layer 30, electron transport layer 60 and electron injection layer 70 increase sequentially.

[0060] Specifically, the working principle of the light-emitting layer 10 generally includes four steps: carrier injection, carrier transport, exciton generation, and radiative luminescence. Specifically, driven by an external electric field, the carrier injection stage includes electrons being injected from the cathode into the electron injection layer 70, and holes being injected from the anode into the hole injection layer 50; the carrier transport stage includes electrons being injected from the electron injection layer 70 into the electron transport layer 60 and ultimately transported to the light-emitting layer 10, and holes being injected from the hole injection layer 50 into the hole transport layer 40 and ultimately transported to the light-emitting layer 10; the exciton generation stage occurs within the light-emitting layer 10, where electrons and holes recombine to generate excitons; the radiative luminescence stage includes the excitons in the light-emitting layer 10 radiatively transitioning back to the ground state and emitting light.

[0061] See Figure 5 , Figure 5 This is a schematic diagram of the structure of one embodiment of the display panel provided in this application. This application also provides a display panel 1000, which can be applied to mobile phones, televisions, tablet computers, laptops, smart wearable devices, etc.

[0062] The display panel 1000 includes multiple organic light-emitting devices 100 arranged in an array, wherein the organic light-emitting devices 100 are the organic light-emitting devices provided in any of the above embodiments. Specifically, by including organic light-emitting devices 100 in the display panel 1000, the capacitance of organic light-emitting devices 100 of different colors in the display panel 1000 is made to be basically the same, thereby avoiding the problem of different proportions of organic light-emitting devices 100 of different colors in the first frame during the lighting process, which would lead to ghosting and color distortion. This improves the subjective visual effect of the display panel 1000 and enhances the user experience.

[0063] See Figure 6 , Figure 6 This is a partial structural schematic diagram of an embodiment of the display panel provided in this application. In one embodiment, the display panel 1000 further includes an anode 200 and a cathode 300 located on both sides of the light-emitting layer 10, wherein the anode 200 is located on the side of the hole injection layer 50 opposite to the light-emitting layer 10, and the cathode 300 is located on the side of the electron injection layer 70 opposite to the light-emitting layer 10.

[0064] Specifically, driven by an external electric field, the anode 200 is used to inject holes into the hole injection layer 50; the cathode 300 is used to inject electrons into the electron injection layer 70. The electrons and holes are finally transferred to the light-emitting layer 10 to recombine and generate excitons. The excitons radiatively transition back to the ground state, thereby making the organic light-emitting device 100 emit light.

[0065] See Figure 7 , Figure 7 This is a schematic diagram of the film layer structure of an embodiment of the display panel provided in this application. In one embodiment, the display panel 1000 further includes a substrate 400, a driving circuit layer 500, a pixel definition layer 600, and an encapsulation layer 700.

[0066] The substrate 400 serves a supporting function in the display panel 1000. It can be a flexible substrate or a rigid substrate. When the substrate 400 is a flexible substrate, its material can be polyimide (PI), or it can be a multilayer structure with alternating organic and inorganic layers. When the substrate 400 is a rigid substrate, its material can be glass or metal. This application does not limit the structure of the substrate 400.

[0067] The driving circuit layer 500 includes a pixel driving circuit for driving the organic light-emitting device 100 to emit light. The pixel driving circuit can be, for example, a 2T1C circuit, a 7T1C circuit, a 7T2C circuit, or a 9T1C circuit. This application does not limit its specific structure.

[0068] In this design, multiple organic light-emitting devices 100 arranged in an array are disposed within a pixel definition layer 600. Specifically, the pixel definition layer 600 can be formed of organic materials such as polyimide (PI), polyamide, benzocyclobutene (BCB), acrylic resin, or phenolic resin, or of inorganic materials such as SiNx. In one embodiment, the pixel definition layer 600 is made of a light-absorbing material to prevent crosstalk between light emitted from adjacent organic light-emitting devices 100.

[0069] The encapsulation layer 700 is used to prevent external moisture and oxygen from affecting the organic light-emitting device 100 and the driving circuit layer 500, among other film layers. The encapsulation layer 700 includes multiple inorganic encapsulation film layers and at least one organic encapsulation film layer stacked together. The at least one organic encapsulation film layer is disposed between the multiple inorganic encapsulation film layers, forming a sealed space that seals the organic encapsulation film layer. In one embodiment, the inorganic and organic encapsulation film layers can be stacked alternately. The inorganic encapsulation film layers can be set as the uppermost and lowermost layers of the encapsulation unit, and the outermost inorganic encapsulation film layer can completely cover the organic encapsulation film layer, thereby forming a barrier space that prevents water and oxygen from entering.

[0070] The above are merely implementation methods of this application and do not limit the patent scope of this application. Any equivalent structural or procedural changes made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. An organic light emitting device, characterized by, The organic light-emitting device is a green organic light-emitting device, which includes a light-emitting layer and an electron blocking layer and a hole blocking layer located on opposite sides of the light-emitting layer. The light-emitting layer is composed of a host material, a guest material, and a co-doperb; and the absolute value of the highest occupied molecular orbital energy level of the co-doperb is located between the absolute value of the highest occupied molecular orbital energy level of the electron blocking layer and the absolute value of the highest occupied molecular orbital energy level of the host material. The absolute value of the highest occupied molecular orbital energy level of the co-doperant lies between the absolute value of the highest occupied molecular orbital energy level of the guest material and the absolute value of the highest occupied molecular orbital energy level of the host material. Furthermore, the absolute value of the highest occupied molecular orbital energy level of the guest material is greater than the absolute value of the highest occupied molecular orbital energy level of the electron blocking layer; The co-doper is used to assist holes in entering the light-emitting layer and to capture a small number of holes, thereby reducing the capacitance of the green organic light-emitting device.

2. The organic light-emitting device according to claim 1, characterized in that, The absolute value of the lowest unoccupied molecular orbital energy level of the co-doper is less than the absolute value of the lowest unoccupied molecular orbital energy level of the host material, and less than the absolute value of the lowest unoccupied molecular orbital energy level of the guest material.

3. The organic light-emitting device according to claim 2, characterized in that, The absolute values ​​of the lowest unoccupied molecular orbital energy levels of the host material, the guest material, and the co-doper are greater than the absolute values ​​of the lowest unoccupied molecular orbital energy levels of the electron blocking layer; and the absolute values ​​of the highest occupied molecular orbital energy levels of the host material, the guest material, and the co-doper are less than the absolute values ​​of the highest occupied molecular orbital energy levels of the hole blocking layer.

4. The organic light-emitting device according to claim 1, characterized in that, The absolute value of the triplet energy level of the co-doper is greater than the absolute value of the triplet energy level of the host material.

5. The organic light-emitting device according to any one of claims 1-4, characterized in that, The doping ratio of the co-dopermeable is 0.4wt%-1wt%.

6. The organic light-emitting device according to claim 5, characterized in that, The doping ratio of the guest material is 5wt%-12wt%.

7. The organic light-emitting device according to claim 5, characterized in that, The co-doper and guest material are uniformly distributed in the luminescent layer.

8. The organic light-emitting device according to claim 1, characterized in that, The organic light-emitting device also includes: A hole transport layer is disposed on the side of the electron blocking layer opposite to the light-emitting layer; A hole injection layer is disposed on the side of the hole transport layer opposite to the light-emitting layer; An electron transport layer is positioned on the side of the hole blocking layer opposite to the light-emitting layer. An electron injection layer is placed on the side of the electron transport layer opposite to the light-emitting layer.

9. A display panel, characterized in that, The display panel includes the organic light-emitting device according to any one of claims 1-8.

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