Display panel and display device

Abstract

The application provides a display panel and a display device. The display panel comprises a plurality of light emitting devices, at least one of which comprises an anode, a cathode, at least two light emitting units, a charge generation layer and a functional layer. The at least two light emitting units are located between the anode and the cathode. The charge generation layer comprises metal particles and is located between any two adjacent light emitting units of the at least two light emitting units. The functional layer comprises a hole transport type material and is in contact with the charge generation layer. The arrangement of the functional layer in the display panel improves the problem of lateral crosstalk of the display panel, and in turn improves the phenomenon of display color cast of the display panel.

Description

Technical Field

[0001] This invention relates to the field of display technology, and more specifically to a display panel and a display device having the display panel. Background Technology

[0002] Organic light-emitting diodes (OLEDs) work by adding an organic light-emitting layer between two electrodes. When electrons and holes meet in this organic material, light is emitted. To improve brightness and efficiency, two or more single-layer OLEDs are connected in series. However, lateral leakage between different pixels can easily occur at the connection point between two adjacent OLEDs, causing color shift, color mixing, and other defects. Summary of the Invention

[0003] In view of this, this application provides a display panel that improves the problem of lateral leakage current in the display panel by configuring the functional layer to contact the metal particles of the charge generation layer between two adjacent light-emitting layers, thereby improving the phenomenon of color shift in the display.

[0004] A first aspect of this application provides a display panel. The display panel includes a plurality of light-emitting devices, at least one of which includes an anode, a cathode, at least two light-emitting units, a charge-generating layer, and a functional layer. The at least two light-emitting units are located between the anode and the cathode. The charge-generating layer includes metal particles and is located between any two adjacent light-emitting units. The functional layer includes a hole-transporting material and is in contact with the charge-generating layer.

[0005] In the above scheme, the functional layer of the hole transport material can contact the metal particles in the charge generation layer to form a hole trap, thereby reducing the lateral flow of holes. This increases the lateral resistance between the charge generation layer and the functional layer, improving the display color shift problem caused by lateral leakage in the display panel.

[0006] In conjunction with the first aspect, in some embodiments, each charge generation layer includes a first charge generation layer and a second charge generation layer. The first charge generation layer has P-type doping and is located between the anode and the cathode, the second charge generation layer has N-type doping and contains metal particles, and is located between the first charge generation layer and the anode, and the functional layer is in contact with the second charge generation layer.

[0007] In the above scheme, the functional layer is in direct contact with the second charge generation layer, which is also in direct contact with the metal particles. This generates hole traps more efficiently, thereby reducing the number of holes flowing laterally and improving the lateral crosstalk problem of the display panel. In turn, it effectively improves the poor color shift phenomenon.

[0008] In conjunction with the first aspect, in some embodiments, the functional layer is located between the first charge generation layer and the second charge generation layer.

[0009] In the above scheme, the functional layer only contacts the charge generation layer. While not affecting the luminous efficiency of the light-emitting unit, i.e. the luminous efficiency of the display panel, it effectively improves the color shift phenomenon of the display panel and enhances the user experience.

[0010] In conjunction with the first aspect, in some embodiments, the display panel further includes a pixel defining layer, which includes a plurality of openings for defining light-emitting devices and a plurality of pixel defining regions. The orthographic projection of the functional layer onto the light-emitting surface of the display panel covers the orthographic projections of the plurality of openings onto the light-emitting surface of the display panel and the orthographic projections of the plurality of pixel defining regions onto the light-emitting surface of the display panel.

[0011] In the above scheme, the functional layer fully covers the upper surface of the second charge generation layer away from the pixel boundary layer. On the one hand, this more effectively prevents the lateral movement of holes, thereby improving the color shift phenomenon. On the other hand, the design of this functional layer is simple to manufacture and saves production costs.

[0012] In conjunction with the first aspect, in some embodiments, each light-emitting unit includes a hole transport layer located between the anode and the cathode. The absolute value of the HOMO energy level of the material of the functional layer is less than or equal to the absolute value of the HOMO energy level of the material of the hole transport layer, and the mobility of the material of the functional layer is greater than or equal to the mobility of the material of the hole transport layer.

[0013] In the above scheme, the material of the functional layer is set according to the above requirements, which can not only reduce the number of holes transported laterally, thereby improving the color deviation problem of the display panel, but also increase the transmission efficiency of electrons between the two light-emitting units, thereby improving the luminous efficiency of the display panel.

[0014] In conjunction with the first aspect, in some embodiments, the material of the functional layer is an aromatic amine derivative. For example, further, the material of the functional layer is any one of 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] and N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine.

[0015] In the above scheme, by using existing aromatic amine derivatives to prepare the functional layer, the functional layer can reduce the number of lateral holes while not affecting the longitudinal electron transport. Therefore, based on existing materials, no additional processing design is required for the functional layer material, simplifying the display panel manufacturing process and thus saving production costs.

[0016] In conjunction with the first aspect, in some embodiments, the functional layer is located between the second charge-generating layer and the anode and is in contact with the second charge-generating layer.

[0017] In the above scheme, the functional layer is in direct contact with the second charge generation layer containing metal particles, which increases the number of hole traps generated on the functional layer, thereby reducing the lateral transmission of holes and effectively improving the display color shift phenomenon in the display panel.

[0018] In conjunction with the first aspect, in some embodiments, the display panel further includes a pixel defining layer, which includes a plurality of openings for defining light-emitting devices and a plurality of pixel defining regions. The orthographic projection of the functional layer onto the light-emitting surface of the display panel coincides with the orthographic projection of the plurality of pixel defining regions onto the light-emitting surface of the display panel.

[0019] In the above scheme, the functional layer only covers the area below the multiple pixel-defined regions corresponding to the charge generation layer. This reduces the impact on the luminous efficiency and lifespan of the display panel while alleviating the problem of color shift caused by lateral leakage.

[0020] In conjunction with the first aspect, in some embodiments, the lateral resistance of the material of the functional layer is greater than the lateral resistance of the material of the second charge generation layer, and the mobility of the material of the functional layer is less than the mobility of the material of the second charge generation layer.

[0021] In the above scheme, the material design of the functional layer can be selected from existing hole transport materials according to the requirements of the above scheme, without the need for research and development of new materials, which simplifies the production process of the display panel and saves production costs.

[0022] In conjunction with the first aspect, in some embodiments, the material of the functional layer is an aromatic amine derivative with a lateral resistivity greater than 1E+10Ω / □. For example, further, the material of the functional layer is either 4,4',4”-tris(carbazole-9-yl)triphenylamine or 4,4',-di(9-carbazole)biphenyl.

[0023] In conjunction with the first aspect, in some embodiments, each light-emitting unit includes a hole injection layer and a hole transport layer located between the anode and the cathode, and an electron transport layer located between the hole transport layer and the cathode. The first charge-generating layer is composed of a first substrate layer doped with a p-type semiconductor material, and the material of the first substrate layer is the same as the material of the hole transport layer. The second charge-generating layer is composed of a second substrate layer doped with a metal material, and the material of the second substrate layer is an electron-type material. Further, the material of the second substrate layer is the same as the material of the electron transport layer.

[0024] In the above scheme, the selection of materials for the first charge generation layer and the second charge generation layer not only further reduces the generation of transverse current, but also improves the efficiency of the light-emitting unit and effectively reduces the driving voltage.

[0025] In conjunction with the first aspect, in some embodiments, the material of the first charge generation layer is the same as the material of the hole injection layer.

[0026] A second aspect of this application provides a display device. This display device includes any of the display panels provided in the first aspect described above. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of at least one light-emitting device in a display panel according to an embodiment of this application.

[0028] Figure 2 This is a schematic diagram of the structure of at least one light-emitting device in a display panel according to another embodiment of this application.

[0029] Figure 3 This is a schematic diagram of the structure of at least one light-emitting device in a display panel according to another embodiment of this application.

[0030] Figure 4 This is a cross-sectional view of at least one light-emitting device in a display panel according to an embodiment of this application.

[0031] Figure 5 This is a cross-sectional view of at least one light-emitting device in a display panel according to another embodiment of this application.

[0032] Figure 6 This is a cross-sectional view of at least one light-emitting device in a display panel according to another embodiment of this application.

[0033] Figure 7 This is a schematic diagram of the structure of at least one light-emitting device in a display panel according to an embodiment of this application, which does not include a functional layer.

[0034] Figure 8 This is a schematic diagram of the structure of at least one light-emitting device in a display panel according to an embodiment of this application, which includes a functional layer.

[0035] Figure 9 These are voltage-current density curves of a light-emitting device with and without a functional layer according to an embodiment of this application.

[0036] Figure 10 These are the current density-current efficiency curves of a light-emitting device with and without a functional layer according to an embodiment of this application. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0038] With increasing demands for brightness, efficiency, and lifespan of organic light-emitting diodes (OLEDs), stacked organic light-emitting diodes (TOLEDs) have emerged. These are OLEDs that connect multiple light-emitting units in series through a charge generation layer (CGL). The charge generation layer not only connects the individual light-emitting units but, more importantly, generates electrical charges and rapidly transfers and injects these charges into the light-emitting units. Therefore, the charge generation layer has a significant impact on the performance of stacked devices.

[0039] Currently, the most commonly used charge generation layers are n-type doped organic layers / p-type doped organic layers. However, the CGL materials used in mass production, i.e., p-doped or n-doped, have high lateral conductivity and exhibit strong lateral leakage. For example, the Li doped in Alq3:Li / NPB:FeCl3 and the existing hole injection layer materials used in mass production have low lateral resistance, which easily leads to lateral transport of charge carriers in the CGL layer. This results in lateral leakage between sub-pixels of different colors, causing color shift, color mixing, and other defects in the multilayer organic light-emitting diode display.

[0040] This application provides a display panel. At least two adjacent light-emitting units in the display panel are provided with a charge-generating layer containing metal particles. A functional layer of hole-transporting material contacts the metal particles in the charge-generating layer to form a hole-trapping trap, thereby reducing lateral hole transport and alleviating the color shift phenomenon caused by lateral leakage in the display panel.

[0041] The display panel and display device according to at least one embodiment of the present application will now be described in detail with reference to the accompanying drawings.

[0042] like Figure 1As shown, in some embodiments, the display panel includes multiple light-emitting devices. At least one light-emitting device includes an anode 1, a cathode 2, at least two light-emitting units (e.g., a first light-emitting unit 31 and a second light-emitting unit 32), a charge-generating layer (e.g., a first charge-generating layer 4 and a second charge-generating layer 5), and a functional layer 6. The at least two light-emitting units are located between the anode 1 and the cathode 2. The charge-generating layer includes metal particles and is located between any two adjacent light-emitting units. The functional layer 6 includes a hole-transporting material and is in contact with the charge-generating layer. The hole-transporting material in the functional layer can contact the metal particles in the charge-generating layer, forming hole traps, thereby preventing lateral hole flow and reducing the number of lateral holes. This increases the lateral resistance between the charge-generating layer and the functional layer, improving the color shift problem caused by lateral crosstalk in the display panel.

[0043] It should be understood that the functional layer only needs to be in contact with the metal particles in the charge generation layer. It can be set horizontally relative to the sub-pixels of the display panel on the surface or inside the charge generation layer. The specific design can be made according to the functional requirements of the display panel and the limitations of the manufacturing process.

[0044] The formation of hole traps depends on the contact between the functional layer and metal particles, and the structure of the charge-generating layer and the distribution of metal particles directly affect the configuration of the functional layer. For example... Figure 1 As shown, in some embodiments, each charge generation layer 4, 5 includes a first charge generation layer 4 and a second charge generation layer 5. The first charge generation layer 4 is P-type doped and located between the anode 1 and the cathode 2. The second charge generation layer 5 is N-type doped and contains metal particles, located between the first charge generation layer 4 and the anode 1, and the functional layer 6 is in contact with the second charge generation layer 5. Specifically, the N-type doped second charge generation layer 5 in the multilayer charge generation layers contains a metallic material, which may include metals, metal oxides, metal halides, metal silicides, or combinations thereof. The functional layer 6 is in direct contact with the second charge generation layer 5 containing metal particles, allowing more metal particles to directly contact the hole transport material, thereby increasing the number of hole traps formed on the contact surface between the functional layer 6 and the second charge generation layer 5, more effectively reducing the lateral flow of holes, thus effectively improving the lateral leakage problem of the display panel, and further more effectively improving the poor color shift phenomenon.

[0045] It should be understood that the specific structure and number of layers of the charge generation layer are not limited to the two-layer structure in the above embodiments. It can be a single-layer structure or a multi-layer structure with more than two layers, such as a three-layer or four-layer functional layer structure. This can be selected according to the functional requirements of the display panel. Furthermore, the design of the charge generation layer is not limited to the two-layer structure in the above embodiments. It can be a single-layer, three-layer, four-layer, or more-layer structure design. Also, there are no limitations on the concentration and material selection of P-type and / or N-type doping in the charge generation; these can all be specifically designed according to the functional requirements of the display panel.

[0046] When the functional layer comes into contact with metal particles, it can form a hole trap, thereby reducing the number of holes transported laterally. The metal particles are mainly distributed in the second charge generation layer. Considering the impact of the functional layer's configuration on the luminous efficiency and lifespan of the display panel, the position of the functional layer relative to the second charge generation layer was designed as follows.

[0047] like Figure 1 As shown, in some embodiments, the display panel includes at least one functional layer, namely a first functional layer 6, which is disposed between the first charge generation layer 4 and the second charge generation layer 5. In this case, the first functional layer 6 only contacts the charge generation layer and does not directly contact the functional film layers in the light-emitting units 31 and 32, namely the electron transport layer and the hole transport layer. While not affecting the luminous efficiency of the light-emitting units 31 and 32, i.e., the luminous efficiency of the display panel, it effectively improves the color shift phenomenon of the display panel and enhances the user experience.

[0048] like Figure 2 As shown, in some embodiments, the display panel includes at least one functional layer, namely a second functional layer 7, which is located between the second light-emitting unit 32 and the second charge-generating layer 5 and is in contact with the lower end face of the second charge-generating layer 5 facing the second light-emitting unit 32. In this way, metal particles in the second charge-generating layer 5 diffuse into the second functional layer 7, and the contact between the second functional layer 7 and the metal particles forms a hole-trapping trap, thereby reducing lateral hole transport and improving the problem of lateral crosstalk between different sub-pixels in the display panel, thus improving the color shift phenomenon observed in the display panel.

[0049] like Figure 3As shown, in some embodiments, the display panel includes at least two functional layers: a first functional layer 6 located between the first charge generation layer 4 and the second charge generation layer 5, and a second functional layer 7 located between the second charge generation layer 5 and the second light-emitting unit 32, and in contact with the lower end surface of the second charge generation layer 5 facing the second light-emitting unit 32. The two functional layers 6 and 7 respectively contact the upper and lower lateral surfaces of the second charge generation layer 5, enabling them to form more hole traps with the metal particles therein, thereby more effectively improving the problem of lateral crosstalk, and further more effectively improving the color shift problem of the display panel.

[0050] like Figure 4 , Figure 5 and Figure 6 As shown, the display panel also includes a pixel defining layer 8 on a substrate 9, the pixel defining layer 8 including a plurality of openings 81 for defining light-emitting devices and a plurality of pixel defining regions. A first charge generating layer 4 and a second charge generating layer 5 sequentially cover the pixel defining layer 8. And as... Figure 4 , Figure 5 and Figure 6 The diagram only shows a structural schematic of the second light-emitting unit 32 located within the opening 81; the structure of the first light-emitting unit is not shown in the diagram. Figure 4 , Figure 5 and Figure 6 As shown in the figure, the structural relationship between the first light-emitting unit and the second light-emitting unit 32 can be referred to Figure 7 and Figure 8 In order to reduce the amount of holes transported laterally at the contact surface of functional layers 6 and 7 and the second charge generation layer 5, while reducing the impact on the luminous efficiency of the display panel, the specific configuration of functional layers 6 and 7 is designed.

[0051] like Figure 4As shown, in some embodiments, the first functional layer 6 is disposed between the first charge generation layer 4 and the second charge generation layer 5, and it does not directly contact the functional film layers of the light-emitting units 31 and 32, that is, it does not participate in the carrier transport between the charge generation layer and the light-emitting units 31 and 32. Therefore, in order to simplify the processing technology of the first functional layer 6, the first functional layer 6 completely covers the pixel defining layer 8, that is, the orthographic projection of the first functional layer 6 on the light-emitting surface of the display panel coincides with the orthographic projection of the multiple openings 81 and the multiple pixel defining areas on the light-emitting surface of the display panel, respectively. The above functional layer design scheme achieves maximum contact area with metal particles, thereby generating more hole traps and more effectively preventing the lateral movement of holes, thereby more effectively improving the problem of lateral leakage between different sub-pixels in the display panel and improving the phenomenon of color shift. On the other hand, the technical solution in which the first functional layer 6 completely covers the pixel defining layer 8 has a simple manufacturing process and saves production costs. For example, the first functional layer 6 can be directly deposited on the common film layer of the second charge generation layer 5.

[0052] It should be understood that the design of the first functional layer 6 is not limited to the scheme of fully covering the pixel defining layer 8. It can also be that the first functional layer 6 covers only the top of at least some of the multiple openings 81, or the first functional layer 6 covers only the top of at least some of the multiple pixel defining areas.

[0053] like Figure 5 As shown, in some other embodiments, when the second functional layer 7 is located between the second charge generation layer 5 and the second light-emitting unit 4 and is in contact with the second charge generation layer 5, the second functional layer 7 covers the area below the second charge generation layer 5 corresponding to the plurality of pixel-defined areas, but does not cover the area above the second charge generation layer 5 corresponding to the plurality of openings 81. That is, the second functional layer 7 does not participate in the longitudinal transmission of electrons between the charge generation layers, for example, the first charge generation layer 4 and the second charge generation layer 5, and the adjacent light-emitting units 31, 32, thereby not affecting the luminous efficiency of the display panel.

[0054] like Figure 6As shown, in some other embodiments, when the display panel includes at least two functional layers, such as a first functional layer 6 and a second functional layer 7, with the first functional layer 6 located between the first charge generation layer 4 and the second charge generation layer 5, and the second functional layer 6 located between the second charge generation layer 5 and the second light-emitting unit 32 and in contact with the second light-emitting unit 32, the first functional layer 6 covers the second charge generation layer 5 above the multiple pixel defining areas 7 and above the multiple openings, thus completely covering the pixel defining layer 8; the second functional layer 7 covers the second charge generation layer 5 below the multiple pixel defining areas. This arrangement of functional layers can more efficiently reduce the lateral flow of holes, thereby more effectively improving the lateral leakage problem in the display panel, thus alleviating the phenomenon of color unevenness in the display and improving the user experience.

[0055] It should be understood that the functional layer is not limited to designs where the functional layer is located between the first and second charge generation layers and / or between the second charge generation layer and the second light-emitting unit. Other designs are also possible, such as placing it between the first charge generation layer and the first light-emitting unit and in contact with the first charge generation layer, or using a separate metal film layer to create more hole-trapping traps through contact with the functional layer. Furthermore, the functional layer is not limited to single-layer or double-layer designs; designs with multiple layers, such as three or four layers, are also possible. The design of the functional layer can be tailored to the specific functional requirements of the display panel.

[0056] Similarly, the placement of the functional layer at different locations relative to the charge generation layer also influences the choice of its material. Each light-emitting unit includes a hole transport layer located between the anode and cathode, and the material of the functional layer is selected differently depending on its location.

[0057] like Figure 1 or Figure 3 As shown, in some embodiments, when the first functional layer 6 is located between the first charge generation layer 4 and the second charge generation layer 5, the absolute value of the HOMO energy level of the material of the first functional layer is less than or equal to the absolute value of the HOMO energy level of the material of the hole transport layer, and the mobility of the material of the first functional layer is greater than or equal to the mobility of the material of the hole transport layer. This selection of the first functional layer material, in addition to increasing the resistance of lateral hole transport and improving the color shift problem of the display panel by cooperating with metal particles, also reduces the energy level of electron transport between the first and second charge generation layers, increasing the longitudinal electron transport efficiency, that is, increasing the electron transport efficiency between the two light-emitting units, thereby increasing the luminous efficiency of the display panel.

[0058] Furthermore, the material of the first functional layer is an aromatic amine derivative. For example, the material of the first functional layer is either 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] or N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine.

[0059] like Figure 2 or Figure 3 As shown, in some embodiments, when the second functional layer 7 is located between the second charge generating layer 5 and the second light-emitting unit 32 and is in contact with the second charge generating layer 5, the lateral resistance of the material of the second functional layer 7 is greater than the lateral resistance of the material of the second charge generating layer, and the mobility of the material of the second functional layer is less than the mobility of the material of the second charge generating layer. Further, the material of the second functional layer is an aromatic amine derivative with a lateral resistance greater than 1E+10Ω / □. For example, further, the material of the second functional layer is either 4,4',4”-tris(carbazole-9-yl)triphenylamine or 4,4',-di(9-carbazole)biphenyl.

[0060] The materials for the first and second functional layers can be designed using existing hole-transporting materials according to the requirements of the above scheme, eliminating the need for new material research and development, thus simplifying the production process and saving production costs. It should be understood that the materials for the first and second functional layers are not limited to those in the above scheme; they can also be designed based on hole-transporting materials according to the specific requirements of the display panel for that functional layer, such as through doping or composite processes, to obtain materials that meet the required functional layer requirements.

[0061] In some embodiments, each light-emitting unit includes a hole injection layer and a hole transport layer located between the anode and the cathode, and an electron transport layer located between the hole transport layer and the cathode. The first charge-generating layer is composed of a first substrate layer doped with a p-type semiconductor material, and the material of the first substrate layer is the same as that of the hole transport layer. The second charge-generating layer is composed of a second substrate layer doped with a metallic material, and the material of the second substrate layer is an electron-type material.

[0062] The metal particles contained in the second charge generation layer have positive charges, allowing the polarity of the adjacent first charge generation layer, i.e., the P-type doped layer, to be separated. This enables holes to be transported from the first charge generation layer to the adjacent light-emitting layer without introducing P-type dopants, reducing current leakage caused by the introduction of P-type dopants. On the other hand, the first charge generation layer contains a material similar to the hole transport layer in the adjacent light-emitting unit, and the second charge generation layer contains a material similar to the electron-type material, such as the electron transport layer, in the adjacent light-emitting unit. This can improve the efficiency of the light-emitting unit and effectively reduce the driving voltage.

[0063] In some embodiments, the material of the first charge generation layer is the same as the material of the hole injection layer. In other embodiments, the second charge generation layer is composed of a metal material doped with the material of the electron transport layer as a substrate.

[0064] In some embodiments, the thickness of the functional layer is For example, further for Therefore, taking into account luminous efficiency, product size, and packaging technology, the thickness of the functional layer was designed to improve the cost-effectiveness of the display panel. It should be understood that the thickness of the functional layer is not limited to the above values ​​and can be appropriately increased or decreased according to product requirements to meet the functional needs of the display panel.

[0065] To verify that adding a functional layer to the light-emitting device of the display panel can improve the display color shift caused by lateral leakage, this embodiment also provides a light-emitting device without a functional layer as a comparative example, and a light-emitting device with a functional layer as an experimental example, as detailed below.

[0066] like Figure 7 As shown, in some embodiments, at least one light-emitting device in a display panel is provided as a comparative example. This light-emitting device includes two light-emitting units, such as a first light-emitting unit 31 and a second light-emitting unit 32, sequentially stacked between an anode 1 and a cathode 2, and a charge-generating layer for connecting the two light-emitting units, such as a first charge-generating layer 4 and a second charge-generating layer 5. Specifically, the first light-emitting unit 31 includes an electron injection layer 311, a first electron transport layer 312, a first hole blocking layer 313, a first light-emitting layer 314, a first electron blocking layer 315, and a first hole transport layer 316 sequentially stacked between the cathode 2 and the first charge-generating layer 4, with the electron injection layer 311 located between the cathode 2 and the first light-emitting layer 314. The second light-emitting unit 32 includes a second electron transport layer 321, a second hole blocking layer 322, a second light-emitting layer 323, a second electron blocking layer 324, a second hole transport layer 325, and a hole injection layer 326 sequentially stacked between the second charge-generating layer 5 and the anode 1, with the hole injection layer 326 located between the second light-emitting layer 323 and the anode 1. Charge generation layers 4 and 5 are used for the two light-emitting units 31 and 32 connected in series. Charge generation layers 4 and 5 include a first charge generation layer 4 and a second charge generation layer 5 containing metal particles. The first charge generation layer 4 is located between the anode 1 and the first light-emitting unit 31, and is in contact with the first hole transport layer 316 in the first light-emitting unit 31. The second charge generation layer 5 is located between the first charge generation layer 4 and the anode 1, and is in contact with the second electron transport layer 321 located in the second light-emitting unit 32.

[0067] In other embodiments, such as Figure 8As shown, based on Figure 8 The provided light-emitting device has a functional layer 6 between the first charge generation layer 4 and the second charge generation layer 5.

[0068] right Figure 8 and Figure 9 The sheet resistance of the composite film layer connecting the two light-emitting units is calculated. Figure 8 The composite film layer in the diagram is a composite film layer structure (p-CGL / n-CGL) consisting of a first charge generation layer 4 and a second charge generation layer 5. Figure 9 The composite film layer in the design has a structure where a first functional layer (p-CGL / functional layer / n-CGL) is located between a first charge-generating layer and a second charge-generating layer. Specifically, the sheet resistance of p-CGL / n-CGL is 1.1*10⁻⁶. 10 Ω / □, the sheet resistance of p-CGL / functional layer / n-CGL is 1.3*10 10 Ω / □, thus it can be seen that after a functional layer is set between the first charge generation layer and the second charge generation layer, the sheet resistance between two adjacent light-emitting units of the display panel increases, that is, the impedance of the leakage current channel between two adjacent light-emitting units increases, thereby improving the problem of lateral leakage between adjacent pixel areas of the display panel and improving the inconsistency of the displayed color surface.

[0069] based on Figure 7 and Figure 8 The two light-emitting devices were tested using a Keithley 2400+PR788 testing system. The relationship between the voltage-current density curves and the current density-current efficiency curves of the two light-emitting devices was measured. Specifically, p-CGL / n-CGL represents... Figure 7 Light-emitting devices that do not contain a functional layer, p-CGL / HTL / n-CGL represent Figure 8 It contains light-emitting devices with functional layers.

[0070] like Figure 9 As shown, the current density-voltage curves of light-emitting devices with functional layers are not significantly different from those without functional layers at different voltages. Therefore, it can be concluded that the electrical characteristics of light-emitting devices with functional layers are not significantly different from those without functional layers.

[0071] like Figure 10 As shown, the luminous efficiency of light-emitting devices with and without functional layers increases slowly and synchronously with the slow increase of current density. Therefore, it can be concluded that light-emitting devices with and without functional layers have essentially the same optical performance; that is, adding a functional layer has virtually no impact on the luminous efficiency of the light-emitting device (display panel).

[0072] In summary, the optimized display panel (such as...) Figure 8 The performance of the display panel before optimization (with added functional layer settings) is compared to that before optimization (e.g.) Figure 7 The photoelectric performance of the non-functional layer is not significantly different, but the problem of lateral leakage is improved.

[0073] It should be understood that the functional film layers in the first light-emitting unit 31 and / or the second light-emitting unit 32 are not limited to the designs described above. Some functional film layers can be reduced, such as omitting hole blocking layers 313, 322 and / or electron blocking layers 315, 324. Furthermore, some and / or all of the aforementioned functional film layers can be single or composite layers, which will not be elaborated upon here. Additionally, the first light-emitting unit 31 and the second light-emitting unit 32 can emit light of any color among red, green, and blue, or other colors. In general, the specific design scheme for the functional film layers in the first light-emitting unit 31 and / or the second light-emitting unit 32 can be tailored to the functional requirements of the display panel.

[0074] This application also provides a display device. The display device includes any of the display panels provided in the first aspect described above. The display device can be any product or component with display functionality, such as a mobile phone, tablet computer, television, navigation system, or in-vehicle application.

[0075] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A display panel, characterized by, Comprising: a plurality of light emitting devices, at least one of the light emitting devices comprising: an anode, a cathode, and at least two light emitting units between the anode and the cathode; a charge generation layer comprising metal particles and between any two adjacent ones of the at least two light emitting units; a functional layer comprising a hole transport material and in contact with the charge generation layer; each of the charge generation layers comprising: a first charge generation layer having a P-type doping and between the anode and the cathode; a second charge generation layer having an N-type doping and comprising the metal particles and between the first charge generation layer and the anode; the functional layer in contact with the second charge generation layer, the functional layer between the first charge generation layer and the second charge generation layer.

2. The display panel of claim 1, wherein, Further comprising: a pixel defining layer comprising a plurality of openings and a plurality of pixel defining regions for defining the light emitting devices; a projection of the functional layer on a light exit face of the display panel covering a projection of the plurality of openings on the light exit face of the display panel and a projection of the plurality of pixel defining regions on the light exit face of the display panel.

3. The display panel of claim 1 or 2, wherein, each of the light emitting units comprising a hole transport layer between the anode and the cathode; a material of the functional layer having an absolute value of a HOMO energy level less than or equal to an absolute value of a HOMO energy level of a material of the hole transport layer and a mobility of the material of the functional layer greater than or equal to a mobility of the material of the hole transport layer.

4. The display panel of claim 3, wherein, the material of the functional layer being an aromatic amine derivative.

5. The display panel of claim 4, wherein, the material of the functional layer being any one of 4,4'-cyclohexylidenebis[N,N-bis(4-methylphenyl)aniline], N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine.

6. The display panel of claim 1, wherein, each of the light emitting units comprising a hole injection layer and a hole transport layer between the anode and the cathode, and an electron transport layer between the hole transport layer and the cathode, the first charge generation layer being composed of a first base layer doped with a P-type semiconductor material, a material of the first base layer being the same as a material of the hole transport layer, and the second charge generation layer being composed of a second base layer doped with a metal material, a material of the second base layer being an electron type material.

7. The display panel of claim 6, wherein, the material of the second base layer being the same as a material of the electron transport layer.

8. The display panel of claim 6, wherein, the material of the first charge generation layer being the same as a material of the hole injection layer.

9. A display device, characterized by comprising: comprising the display panel of any one of claims 1-8.

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