CN114914376A - Display panel, manufacturing method thereof and display device - Google Patents

Abstract

The embodiment of the invention provides a display panel, a manufacturing method thereof and a display device. The display panel comprises a substrate and a plurality of pixel units positioned on the substrate, wherein each pixel unit comprises a first electrode positioned on the substrate and a pixel definition layer, and a plurality of openings are formed in positions, opposite to the first electrodes, of the pixel definition layer. And the hole transport layer is arranged on one side of the first electrode, which is far away from the substrate base plate, and is opposite to the opening. A light emitting layer on the hole transport layer; an electron transport layer covering the light emitting layer; and the second electrode is arranged on one side of the electron transmission layer, which is far away from the substrate base plate. Wherein the hole transport layer is formed of a first material and a second material, the hole mobility of the first material is greater than the hole mobility of the second material, and the absolute value of the HOMO level of the first material is smaller than the absolute value of the HOMO level of the second material.

Description

Display panel, manufacturing method thereof and display device

Technical Field

The invention relates to the technical field of display, in particular to a display panel, a manufacturing method of the display panel and a display device.

Background

Currently, with the development of display manufacturing technology, the display technology is rapidly developed, such as lcd (liquid Crystal display) display, OLED (Organic Light-Emitting Diode) display, and the like.

The OLED display utilizes the organic electric self-luminous diode to form colors, and does not need to be additionally provided with a light source. It has the advantages of high contrast, thin thickness, wide viewing angle, etc., and is more and more popular with consumers.

However, in the current OLED display manufacturing process, since there may be overlapping of the light emitting materials with different colors during evaporation, when one individual sub-pixel is driven, the current may be conducted laterally through the overlapping layer material, so that crosstalk of display colors may be generated between adjacent sub-pixel units. Meanwhile, due to the existence of the above conditions, the display panel may also have color cast conditions, thereby affecting the display effect.

Disclosure of Invention

Embodiments of the present invention provide a display panel, a manufacturing method thereof, and a display device, so as to reduce color crosstalk and color shift of a display, and further improve a display effect.

The first aspect of the present application provides a display panel, including a substrate base plate and a plurality of pixel units located on the substrate base plate, the pixel units include a first electrode located on the substrate base plate and a pixel definition layer, and a plurality of openings are provided at positions of the pixel definition layer opposite to the first electrode. The hole transport layer is arranged on one side, far away from the substrate base plate, of the first electrode, and the hole transport layer is arranged opposite to the opening. A light-emitting layer on the hole transport layer; an electron transport layer covering the light emitting layer; and the second electrode is arranged on one side of the electron transmission layer, which is far away from the substrate base plate. Wherein the hole transport layer is formed of a first material and a second material, a hole mobility of the first material is greater than a hole mobility of the second material, and an absolute value of a HOMO level of the first material is smaller than an absolute value of a HOMO level of the second material.

In the present application, the first material is a low-capacitance material, and has a large hole transport rate, and accordingly, the absolute value of the HOMO level of the first material is smaller than the absolute value of the HOMO level of the second material. When the first material is independently used as the material of the hole transport layer, the whole picture is uniform in performance, the color gray scale is normal, the phenomenon of color cast is not easy to occur, color crosstalk can not occur during low-gray-scale display, and color cast can occur after high-temperature reliability operation. The second material is a high-capacitance material, and has a longitudinal hole transport rate smaller than that of the first material. When the second material is used alone as the material of the hole transport layer, after high-temperature reliable operation, the color gray scale is normal, but color crosstalk exists in the low gray scale. Therefore, the second material with the high-capacitance characteristic and the first material with the low-capacitance characteristic are organically combined, the picture display effect is neutralized, the color crosstalk and the color cast under the low gray scale are favorably improved, and the display effect is favorably improved.

The display panel according to the embodiment of the present application may further have the following additional technical features:

in some embodiments of the present application, the hole transport layer includes a red light hole transport layer, a green light hole transport layer, and a blue light hole transport layer disposed in the same layer on a side of the first electrode facing away from the substrate, at least one of the red light hole transport layer, the green light hole transport layer, and the blue light hole transport layer being formed of the first material and the second material;

the light-emitting layer comprises a red light-emitting layer arranged on the red light hole transport layer, a green light-emitting layer arranged on the green light hole transport layer and a blue light-emitting layer arranged on the blue light hole transport layer.

In some embodiments of the present application, at least one of the red light hole transport layer, the green light hole transport layer, and the blue light hole transport layer comprises a first layer comprising the first material and a second layer comprising the second material, the second layer being disposed on a side of the first layer facing away from the substrate base.

In some embodiments of the present application, the green hole transport layer comprises a first layer and a second layer.

In some embodiments of the present application, at least one of the red, green, and blue hole transport layers is formed by doping the first and second materials.

In some embodiments of the present application, the doping ratio of the first material and the second material is 1: 1.

In some embodiments of the present application, the proportion of the first material is greater than the proportion of the second material.

In some embodiments of the present application, the first material and the second material are small molecules of a monoarylamine type, the spatial arrangement orientation of the first material and the second material is different, the first material is a planar structure, and the second material is a longitudinal structure.

In some embodiments of the present application, at least one protrusion is disposed on the pixel defining layer between two adjacent openings.

In some embodiments of the present application, at least one groove is disposed on the pixel defining layer between two adjacent openings.

In a second aspect of the present application, a method for manufacturing a display panel is provided, including:

forming a substrate base plate;

forming a first electrode and a pixel defining layer on the substrate, wherein a plurality of openings are arranged at positions of the pixel defining layer opposite to the first electrode;

forming a hole transport layer on the first electrode, the hole transport layer being disposed opposite to the opening, the hole transport layer being formed of a first material and a second material, the first material having a hole mobility greater than that of the second material, the first material having a HOMO level having an absolute value smaller than that of the second material;

forming a light emitting layer on the hole transport layer;

forming an electron transport layer on the light emitting layer;

and forming a second electrode on the electron transport layer.

In some embodiments of the present application, the step of forming a hole transport layer on the first electrode comprises:

forming a common layer on the first electrode;

forming a blue light hole transport layer opposite to the opening on the common layer, and forming a blue light emitting layer on the blue light hole transport layer;

forming a red light hole transport layer opposite to the opening on the common layer, and forming a red light emitting layer on the red light hole transport layer;

and forming a green light hole transport layer opposite to the opening on the common layer, and forming a green light emitting layer on the green light hole transport layer, wherein at least one of the red light hole transport layer, the green light hole transport layer and the blue light hole transport layer is formed by a first material and a second material, the hole mobility of the first material is greater than that of the second material, and the absolute value of the HOMO level of the first material is smaller than that of the second material.

In some embodiments of the present application, the step of forming a green light emitting layer on the green hole transport layer, the green hole transport layer being disposed opposite to the opening, on the common layer, includes: forming a first layer on the common layer, the first layer comprising the first material;

forming a second layer on the first layer, the second layer comprising the second material;

the green light emitting layer is formed on the second layer.

In some embodiments of the present application, the step of forming a green light emitting layer on the green hole transport layer, the green hole transport layer being disposed opposite to the opening, on the common layer, includes:

and forming the green light hole transport layer formed by doping the first material and the second material on the common layer, and forming a green light emitting layer on the green light hole transport layer.

A third aspect of the application provides a display device comprising the display panel of the first aspect.

Of course, not all of the advantages described above need to be achieved at the same time in the practice of any one product or method of the invention.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other embodiments can be obtained by those skilled in the art according to the drawings.

Fig. 1 is a schematic structural diagram of a display panel according to an embodiment of the present application;

FIG. 2 is a schematic diagram of the capacitive characteristics of a first material and a second material in accordance with an embodiment of the present application;

FIG. 3 is a schematic structural diagram of a display panel according to an embodiment of the present disclosure;

FIG. 4 is a schematic structural diagram of a display panel according to an embodiment of the present disclosure;

FIG. 5 is a schematic spectrum of a first material alone as a green hole transport layer in accordance with an embodiment of the present application;

FIG. 6 is a schematic spectrum of a second material alone as a green hole transport layer in an embodiment of the present application;

FIG. 7 is a schematic spectrum diagram of a green light hole transport layer formed from a first material and a second material in an embodiment of the present application;

FIG. 8 is a schematic diagram of a groove structure according to an embodiment of the present application;

FIG. 9 is a schematic view of a bump according to an embodiment of the present application;

FIG. 10 is a flowchart illustrating a method for fabricating a display panel according to an embodiment of the present disclosure;

FIG. 11 is a flowchart illustrating another method of fabricating a display panel according to an embodiment of the present disclosure;

FIG. 12 is a flowchart illustrating a method of fabricating a display panel according to an embodiment of the present disclosure;

fig. 13 is a flowchart of a method for manufacturing a display panel according to an embodiment of the present disclosure.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived from the embodiments of the present invention by those skilled in the art based on the description, are within the scope of the present invention.

The OLED display utilizes the organic electric self-luminous diode to form colors, and does not need to be additionally provided with a light source. It has the advantages of high contrast, thin thickness, wide viewing angle, etc., and is more and more popular with consumers.

However, in the current OLED display manufacturing process, since there may be overlapping of the light emitting materials with different colors during evaporation, when a single pixel is driven, the current may be conducted laterally through the overlapping layer of material, so that crosstalk of display colors may occur between adjacent sub-pixel units. Meanwhile, due to the existence of the above conditions, the display panel may also have color cast conditions, thereby affecting the display effect.

Based on the above situation, the present application provides a display panel, a manufacturing method thereof, and a display device, so as to facilitate reducing the situations of color crosstalk and color cast of a display, and further facilitate improving the display effect.

As shown in fig. 1, a first aspect of the present application provides a display panel 10, which includes a substrate 100 and a plurality of pixel units located on the substrate 100. The pixel unit includes a first electrode 110, a pixel defining layer 120, a hole transport layer 140, a light emitting layer 150 on the hole transport layer 140, an electron transport layer 160, and a second electrode 170 on a substrate 100. The pixel defining layer 120 is provided with a plurality of openings 121 at positions opposite to the first electrode 110. The hole transport layer 140 is disposed on a side of the first electrode 110 away from the substrate 100, and the hole transport layer 140 is disposed opposite to the opening 121. The electron transport layer 160 covers the light emitting layer 150, and the second electrode 170 is disposed on a side of the electron transport layer 160 facing away from the substrate 100. Wherein the hole transport layer 140 is formed of a first material 200 and a second material 300, the hole mobility of the first material 200 is greater than the hole mobility of the second material 300, and the absolute value of the HOMO level of the first material 200 is smaller than the absolute value of the HOMO level of the second material 300.

The embodiment of the application improves the hole transport layer 140 of the OLED display panel 10, thereby being beneficial to reducing the color crosstalk and color cast of the display image. The display panel 10 includes a substrate 100 and a plurality of pixel units. The pixel units are used for emitting light with different colors. The first electrode 110 may be a transparent electrode layer serving as an anode for supplying holes. The first electrode may be formed using a transparent conductive material having a relatively large work function, such as Indium Tin Oxide (ITO), Zinc Tin Oxide (ZTO), Indium Zinc Oxide (IZO), zinc oxide, Gallium Indium Zinc Oxide (GIZO), or the like. In the embodiment of the present application, the first electrode 110 may also be a composite layer formed of a transparent conductive material and a metal, for example, an indium tin oxide/silver/indium tin oxide composite layer, i.e., an ITO/Ag/ITO composite layer.

The pixel defining layer 120 is disposed on the same layer as the first electrode 110, and openings 121 are disposed at positions of the pixel defining layer 120 corresponding to the first electrode 110, each opening 121 defining a light emitting sub-pixel. Generally, a pixel unit includes three sub-pixel units, namely, three sub-pixel units of red, green and blue. In other embodiments, a pixel unit may further include four sub-pixel units, such as four sub-pixel units of red, green, blue, and white. Of course, a pixel unit may also include other arrangement rules of sub-pixels with different colors, and the application is not limited thereto.

In some embodiments, as shown in FIG. 1, the display panel 10 further includes a common layer 130. The common layer 130 may further include a hole injection layer, which is advantageous for reducing a barrier for injecting holes from the anode, so that holes can be efficiently injected from the anode into the light emitting layer. In other embodiments, the common layer 130 may also serve as a common hole transport layer, which is advantageous for using less FFM (fine metal mask) process, so that the process flow is simplified.

The hole transport layer 140 serves to facilitate transport of holes into the light emitting layer 150. The hole transport layer 140 matches the work function between its corresponding electrode and light emitting layer. The light emitting layer 150 is a site where electrons and holes are combined to emit specific light in the OLED. The light emitting layer 150 may be obtained by a transfer process including an inkjet, a spin or printing process, by heat or laser using a host substrate, or the like. The electron transport layer 160 serves to facilitate the transport of electrons into the light emitting layer 150, and is generally composed of organic material molecules.

The second electrode 170 may be a cathode, which covers the electron transport layer 160. The second electrode 170 may be formed of a metal material, such as Ag, Al, Pt, Au, Cr, W, Mo, Ti, Pd, or the like, or an alloy of these materials. The second electrode layer may be obtained by a sputtering process, a Chemical Vapor Deposition (CVD) process, an Atomic Layer Deposition (ALD) process, a vacuum deposition process, a printing process, or the like. Generally, an electron injection layer may be further disposed between the second electrode 170 and the electron transport layer 160. The electron injection layer can be formed using an alkali metal, an alkaline earth metal, a fluoride of these metals, an oxide of these metals, or the like. The light emitting principle of the OLED display panel is as follows: under the driving of an applied voltage, electrons enter the electron transport layer 160 from the second electrode 170, holes enter the hole transport layer 140 from the first electrode 110, the holes and the electrons recombine in the light emitting layer to generate excitons, and the excitons radiatively transition back to the ground state and emit visible light.

In the present application, the hole transport layer 140 is formed of a first material 200 and a second material 300. The hole mobility of the first material 200 is greater than the hole mobility of the second material 300, and the absolute value of the HOMO level of the first material 200 is smaller than the absolute value of the HOMO level of the second material 300. Fig. 2 is a schematic diagram comparing the capacitance characteristics of the first material 200 and the second material 300. The first material 200 is a low capacitance material with a high longitudinal hole transport rate. When the first material 200 is used alone as the material of the hole transport layer 140, the overall picture is uniform in appearance, the color gray scale is normal, the color cast phenomenon is not easy to occur, the color crosstalk does not occur during the low gray scale display, but the color cast occurs after the high-temperature reliable operation. The second material 300 is a high capacitance material having a longitudinal hole transport rate less than the hole transport rate of the first material 200. When the second material 300 is used alone as the material of the hole transport layer 140, the color gradation is normal after high-temperature reliability operation, but color crosstalk occurs at a low gradation. Therefore, in the embodiment of the present application, the second material 300 with high capacitance characteristics and the first material 200 with low capacitance characteristics are organically combined, so as to neutralize the image display effect, which is beneficial to improving the color crosstalk and the color cast under low gray scale, and is further beneficial to improving the display effect.

As shown in fig. 3, in some embodiments of the present application, the hole transport layer 140 includes a red light hole transport layer 141, a green light hole transport layer 142, and a blue light hole transport layer 143 disposed in the same layer on a side of the first electrode 110 facing away from the substrate 100, and at least one of the red light hole transport layer 141, the green light hole transport layer 142, and the blue light hole transport layer 143 is formed of a first material 200 and a second material 300. The light emitting layer 150 includes a red light emitting layer 151 disposed on the red light hole transport layer 141, a green light emitting layer 152 disposed on the green light hole transport layer 142, and a blue light emitting layer 153 disposed on the blue light hole transport layer 143.

In this embodiment, each pixel unit includes three sub-pixels, i.e., red, green, and blue sub-pixel units. Each color sub-pixel unit comprises a light-emitting layer and a hole transport layer of the color. That is, the light emitting layer of each color is provided with an independent hole transport layer corresponding to the color of the light emitting layer thereof. The independent hole transport layers described in this embodiment can be understood as being dedicated to the hole transport layers of the different color light emitting layers, i.e., the red light hole transport layer 141 under the red light emitting layer 151, the green light hole transport layer 142 under the green light emitting layer 152, and the blue light hole transport layer 143 under the blue light emitting layer 153. The hole transport layer corresponding to each color light emitting layer can supplement the microcavity effect due to the difference of pixels by adjusting the thickness. For example, the red light emitting layer 151 may have a longer hole transport distance and the red light hole transport layer 141 may have a larger thickness. For the thickness of the hole transport layer of the light emitting layer of different colors, one skilled in the art can design the thickness of the red light transmission path to be 2 times of the wavelength of red light according to the pixel of the light emitting layer of the color.

In this embodiment, at least one of the red, green, and blue hole transport layers 141, 142, and 143 is formed of the first and second materials 200 and 300. The second material 300 with high capacitance characteristic and the first material 200 with low capacitance characteristic are organically combined, thereby being beneficial to neutralizing the picture display effect, improving the color crosstalk and the color cast condition under low gray scale, and further being beneficial to improving the display effect.

Specifically, as shown in fig. 4, in some embodiments of the present application, at least one of the red, green, and blue hole transport layers 141, 142, 143 comprises a first layer 1401 and a second layer 1402, the first layer 1401 comprising the first material 200, the second layer 1402 comprising the second material 300, the second layer 1402 being disposed on a side of the first layer 1401 facing away from the substrate 100. In this embodiment, the second material 300 and the first material 200 are combined in the following manner: the first material 200 and the second material 300 form a first layer 1401 and a second layer 1402, respectively, and are sequentially stacked onto the base substrate 100. Also, the first layer 1401 formed of the first material 200 of the low capacitance characteristic is closer to the base substrate 100 than the second layer 1402 formed of the second material 300 of the high capacitance characteristic. With this arrangement, the energy level matching between the first electrode 110 and the light emitting layer 150 is more uniform, which is beneficial to improving the hole transport property in the longitudinal direction of the interface, i.e., the thickness direction of the display panel. The longitudinal hole transmission rate of the first material 200 is relatively large, so that holes can quickly enter the second material 300 with the high capacitance characteristic from the first material 200 with the low capacitance characteristic, the probability of current transverse transmission is reduced, the color crosstalk condition and the low gray scale color cast condition can be improved, and the display effect is improved.

Further, as shown in fig. 4, the green hole transport layer 142 includes a first layer 1401 and a second layer 1402. That is, in the present embodiment, the green hole transport layer 142 is composed of two film layers of the first layer 1401 and the second layer 1402. As shown in fig. 5, is a spectrum diagram of the first material 200 alone as the material of the green hole transporting layer 142 under the green light emitting layer 152. It can be seen that the green spectrum is single at low gray levels and no crosstalk phenomenon occurs (no light intensity display of the wavelengths of other colors of light occurs). However, after high temperature reliability operation, the overall picture is very dark and the gray scale brightness is very high. As shown in fig. 6, which is a spectrum diagram when the second material 300 alone is used as the material of the green hole transporting layer 142 under the green light emitting layer 152. It can be seen that a red spectrum exists in the green spectrum of the low gray scale display, and the ratio of the intensity of the two is about 80%. However, the color gradation was normal after high-temperature reliability operation. Therefore, in this embodiment, the first material 200 and the second material 300 are respectively formed into two film structures, namely, the first layer 1401 and the second layer 1402, of the green light hole transport layer 142, which is further beneficial to improving the hole transport property in the longitudinal direction of the green light hole transport layer 142, that is, the thickness direction of the display panel 10, so that holes can quickly enter the second material 300 with a high capacitance property from the first material 200 with a low capacitance property, thereby reducing the probability of current transverse transport, and further being beneficial to improving the display effect.

In some embodiments of the present application, as shown in fig. 3, at least one of the red, green, and blue hole transport layers 141, 142, 143 is formed by doping the first and second materials 200, 300. In this embodiment, the first material 200 and the second material 300 are combined in the following manner: the first material 200 and the second material 300 form at least one of the red light hole transport layer 141, the green light hole transport layer 142, and the blue light hole transport layer 143 by doping. Therefore, the method is beneficial to neutralizing the picture display effect when the first material 200 or the second material 300 is independently used as a hole transport layer, and further beneficial to improving the color cast and the color crosstalk condition and improving the display effect.

In some embodiments, green hole transport layer 142 is formed from first material 200 and second material 300 doped. As shown in fig. 7, a spectrum effect diagram of forming a green light hole transport layer 142 by doping a first material 200 and a second material 300 or forming a green light hole transport layer 142 by forming the first layer 1401 and the second layer 1402 of the green light hole transport layer 142 by forming the first material 200 and the second material 300, respectively. Therefore, after the first material 200 and the second material 300 are mixed to form the green hole transport layer 142, the color shift and the color crosstalk can be improved, and the display effect can be improved.

Further, the doping ratio of the first material 200 and the second material 300 is 1: 1. The arrangement is favorable for balancing the color crosstalk condition and the low gray scale color cast condition, and the image display effect is improved to the maximum extent.

In other embodiments, the doping ratio of the two materials can be flexibly changed. For example, when it is desired to reduce the picture color crosstalk, the proportion of the first material 200 may be increased appropriately so that the proportion of the first material 200 is greater than the proportion of the second material.

In some embodiments of the present application, the first material 200 and the second material 300 are small molecules of monoarylamine type, the spatial arrangement orientation of the first material 200 and the second material 300 is different, the first material 200 is a planar structure, and the second material 300 is a longitudinal structure. This example illustrates the difference in the spatial molecular arrangement of the first material 200 and the second material 300. The first material 200 is a planar structure and the second material 300 is a longitudinal structure.

In some embodiments of the present application, as shown in fig. 9, at least one protrusion 122 is disposed on the pixel defining layer 120 between two adjacent openings 121. The present embodiment also reduces the probability of lateral cross talk of the current by a scheme of physical blocking. Specifically, the pixel defining layer 120 has a plurality of openings 121, and each opening 121 defines one sub-pixel unit. The protrusion 122 is disposed on the pixel defining layer 120 between two adjacent openings 121, so that the lateral transmission resistance of the material can be increased, and the color crosstalk condition and the low gray scale color cast condition between two sub-pixel units can be improved, thereby improving the display effect. The protrusion 122 may be formed by a technique such as exposure etching.

In some embodiments of the present application, as shown in fig. 8, at least one groove 123 is disposed on the pixel defining layer 120 between two adjacent openings 121. The embodiment of the present application proposes another physical blocking scheme, that is, a groove 123 is disposed on the pixel defining layer 120 between two adjacent openings 121. Therefore, materials among the sub-pixel units with different colors are separated, the capability of current transverse transmission is further reduced, the color crosstalk condition between the two sub-pixel units and the color cast condition under low gray scale are further improved, and the display effect is improved. The recess 123 may be formed by a technique such as exposure etching.

Further, a part of the groove 123 is located on the substrate base 100. The depth of the groove 123 can be flexibly set. In this embodiment, the groove 123 may penetrate through the pixel defining layer 120 and further penetrate into the substrate 100. Therefore, the overlapping condition of the materials of the light emitting layers 150 with different colors can be cut off from the film layer where the substrate 100 is located, so that the capability of further blocking the transverse transmission of current is facilitated, the color crosstalk condition and the low gray scale color cast condition between two sub-pixel units are further facilitated to be improved, and the display effect is improved.

In some embodiments of the present application, as shown in fig. 1, display panel 10 further includes a thin-film transistor layer 102 located between substrate 100 and first electrode 110, where thin-film transistor layer 102 is used to drive a plurality of pixel units. The substrate base plate 100 may be a glass base plate. Thin-film transistor layer 102 typically includes a gate electrode, a gate insulating layer, an active layer, a source drain metal layer, and the like. By providing thin-film transistor layer 102, the switching of the pixel cells may be controlled, thereby driving the color display of each pixel cell. In some embodiments, thin-film-transistor layer 102 may be a top-gate structure, and in other embodiments, thin-film-transistor layer 102 may be a bottom-gate structure.

In some embodiments, the display panel 10 further includes a thin film encapsulation layer covering the second electrode 170, which is beneficial to isolate external moisture and improve the lifespan of the OLED display panel 10.

As shown in fig. 10, a second aspect of the present application provides a method for manufacturing a display panel, including:

forming a base substrate 100;

forming a first electrode 110 and a pixel definition layer 120 on a substrate 100, wherein a plurality of openings 121 are formed at positions of the pixel definition layer 120 opposite to the first electrode 110;

forming a hole transport layer 140 on the first electrode 110, the hole transport layer 140 being disposed opposite to the opening 121, the hole transport layer 140 being formed of a first material 200 and a second material 300, the first material 200 having a hole mobility greater than that of the second material 300, the first material 200 having an HOMO level having an absolute value smaller than that of the second material 300;

forming a light emitting layer 150 on the hole transport layer 140;

forming an electron transport layer 160 on the light emitting layer 150;

a second electrode 170 is formed on the electron transport layer 160.

The display panel 10 manufactured by the method for manufacturing a display panel according to the embodiment of the present application has a relatively excellent display effect. Specifically, the hole transport layer 140 and the light emitting layer 150 may be formed through an evaporation process. The hole transport layer 140 is formed of a first material 200 and a second material 300. The hole mobility of the first material 200 is greater than the hole mobility of the second material 300, and the absolute value of the HOMO level of the first material 200 is less than the absolute value of the HOMO level of the second material 300. The first material 200 is a low capacitance material with a high longitudinal hole transport rate. When the first material 200 is used alone as a material of the hole transport layer 140, the overall picture is uniform in appearance, the color gray scale is normal, the phenomenon of color cast is not easy to occur, color crosstalk does not occur during low-gray-scale display, but color cast occurs after high-temperature reliable operation. The second material 300 is a high capacitance material having a longitudinal hole transport rate less than the hole transport rate of the first material 200. When the second material 300 is used alone as the material of the hole transport layer 140, the color gradation is normal after high-temperature reliability operation, but color crosstalk occurs at a low gradation. Therefore, in the manufacturing method of the embodiment of the application, the second material 300 with the high capacitance characteristic and the first material 200 with the low capacitance characteristic are organically combined, so that the effect of image display is neutralized, the conditions of color cast and color crosstalk are favorably improved, and the display effect is favorably improved.

As shown in fig. 11, in some embodiments of the present application, the step of forming a hole transport layer 140 on the first electrode 110 includes:

forming a common layer 130 on the first electrode 110;

forming a blue hole transport layer 143 disposed opposite to the opening 121 on the common layer 130, and forming a blue light emitting layer 153 on the blue hole transport layer 143;

forming a red light hole transport layer 141 disposed opposite to the opening 121 on the common layer 130, and forming a red light emitting layer 151 on the red light hole transport layer 141;

a green hole transport layer 142 disposed opposite to the opening 121 is formed on the common layer 130, and a green light emitting layer 152 is formed on the green hole transport layer 142, wherein at least one of the red, green, and blue hole transport layers 141, 142, and 143 is formed of a first material 200 and a second material 300, the first material 200 has a hole mobility greater than that of the second material 300, and an absolute value of a HOMO level of the first material 200 is smaller than that of the second material 300.

In this embodiment, each pixel unit includes three sub-pixels, i.e., red, green, and blue sub-pixel units. At least one of the red, green, and blue hole transport layers 141, 142, and 143 is formed of a first material 200 and a second material 300. The second material 300 with high capacitance characteristic and the first material 200 with low capacitance characteristic are organically combined, thereby being beneficial to neutralizing the picture display effect, improving the color crosstalk and the color cast condition under low gray scale, and further being beneficial to improving the display effect.

As shown in fig. 12, in some embodiments of the present application, the step of forming a green hole transport layer 142 disposed opposite to the opening 121 on the common layer 130, and forming a green light emitting layer 152 on the green hole transport layer 142, includes:

forming a first layer 1401 over the common layer 130, the first layer 1401 comprising a first material 200;

forming a second layer 1402 on the first layer 1401, the second layer 1402 comprising the second material 300;

the green light emitting layer 152 is formed on the second layer 1402.

In the present embodiment, the green hole transport layer 142 includes a first layer 1401 formed of the first material 200 and a second layer 1402 formed of the second material 300, and is sequentially stacked onto the common layer 130. Also, the first layer 1401 is closer to the common layer 130 than the second layer 1402. By such arrangement, the energy level matching between the first electrode 110 and the green light emitting layer 150 is more uniform, which is further beneficial to improving the transmission of holes in the longitudinal direction of the interface, i.e., the thickness direction of the display panel, so that the holes quickly enter the second material 300 with high capacitance from the first material 200 with low capacitance, thereby reducing the probability of current transverse transmission, further being beneficial to improving the color crosstalk condition and the low gray scale color cast condition, and improving the display effect.

As shown in fig. 13, in some embodiments of the present application, the step of forming a green hole transport layer 142 disposed opposite to the opening 121 on the common layer 130, and forming a green light emitting layer 152 on the green hole transport layer 142, includes:

a green hole transport layer 142 doped with the first material 200 and the second material 300 is formed on the common layer 130, and a green light emitting layer 152 is formed on the green hole transport layer 142.

In this embodiment, the green hole transport layer 142 is formed by doping the first material 200 and the second material 300, which is favorable for neutralizing the image display effect when the first material 200 or the second material 300 is used as the green hole transport layer alone, and further favorable for improving the color shift and the color crosstalk and improving the display effect, as shown in fig. 7.

A third aspect of the present application provides a display device comprising the display panel 10 of the first aspect. The display device of the embodiment of the application has excellent display effect. Specifically, the hole transport layer 140 in the display panel 10 is formed of the first material 200 and the second material 300. The first material 200 is a low-capacitance characteristic material, the second material 300 is a high-capacitance characteristic material, the hole mobility of the first material 200 is greater than that of the second material 300, and the absolute value of the HOMO level of the first material 200 is smaller than that of the HOMO level of the second material 300. The embodiment of the application organically combines two materials with different characteristics, thereby neutralizing the image display effect, being beneficial to improving the color cast and the color crosstalk condition and further being beneficial to improving the display effect.

It is noted that in the drawings, the sizes of layers and regions may be exaggerated for clarity of illustration. Also, it will be understood that when an element or layer is referred to as being "on" another element or layer, it can be directly on the other element or layer or intervening layers may also be present. In addition, it will be understood that when an element or layer is referred to as being "under" another element or layer, it can be directly under the other element or intervening layers or elements may also be present. In addition, it will also be understood that when a layer or element is referred to as being "between" two layers or elements, it can be the only layer between the two layers or elements, or more than one intermediate layer or element may also be present. Like reference numerals refer to like elements throughout.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

All the embodiments in the present specification are described in a related manner, and the same and similar parts among the embodiments may be referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the system embodiment, since it is substantially similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.

Claims (15)

1. A display panel comprising a substrate base and a plurality of pixel cells on the substrate base, the pixel cells comprising:

the pixel structure comprises a first electrode and a pixel defining layer, wherein the first electrode and the pixel defining layer are positioned on the substrate, and a plurality of openings are formed in the positions, opposite to the first electrode, of the pixel defining layer;

the hole transport layer is arranged on one side, far away from the substrate base plate, of the first electrode, and the hole transport layer is arranged opposite to the opening;

a light emitting layer on the hole transport layer;

an electron transport layer covering the light emitting layer; and

the second electrode is arranged on one side of the electron transmission layer, which is far away from the substrate base plate;

wherein the hole transport layer is formed of a first material and a second material, a hole mobility of the first material is greater than a hole mobility of the second material, and an absolute value of a HOMO level of the first material is smaller than an absolute value of a HOMO level of the second material.

2. The display panel according to claim 1, wherein the hole transport layer comprises a red light hole transport layer, a green light hole transport layer, and a blue light hole transport layer which are provided in the same layer on a side of the first electrode facing away from the substrate, and at least one of the red light hole transport layer, the green light hole transport layer, and the blue light hole transport layer is formed of the first material and the second material;

the light-emitting layer comprises a red light-emitting layer arranged on the red light hole transport layer, a green light-emitting layer arranged on the green light hole transport layer and a blue light-emitting layer arranged on the blue light hole transport layer.

3. The display panel of claim 2, wherein at least one of the red, green, and blue hole transport layers comprises a first layer comprising the first material and a second layer comprising the second material, the second layer being disposed on a side of the first layer facing away from the substrate.

4. The display panel of claim 3, wherein the green hole transport layer comprises a first layer and a second layer.

5. The display panel according to claim 2, wherein at least one of the red light hole transport layer, the green light hole transport layer, and the blue light hole transport layer is formed by doping the first material and the second material.

6. The display panel according to claim 5, wherein the doping ratio of the first material to the second material is 1: 1.

7. The display panel according to claim 5, wherein the proportion of the first material is greater than the proportion of the second material.

8. The display panel according to claim 1, wherein the first material and the second material are small molecules of monoarylamine type, the first material and the second material have different spatial arrangement orientations, the first material has a planar structure, and the second material has a longitudinal structure.

9. The display panel according to claim 1, wherein at least one protrusion is disposed on the pixel defining layer between two adjacent openings.

10. The display panel according to claim 1, wherein at least one groove is disposed on the pixel defining layer between two adjacent openings.

11. A method for manufacturing a display panel is characterized by comprising the following steps:

forming a substrate base plate;

forming a first electrode and a pixel defining layer on the substrate, wherein a plurality of openings are arranged at positions of the pixel defining layer opposite to the first electrode;

forming a hole transport layer on the first electrode, the hole transport layer being disposed opposite to the opening, the hole transport layer being formed of a first material and a second material, the first material having a hole mobility greater than that of the second material, the first material having a HOMO level having an absolute value smaller than that of the second material;

forming a light emitting layer on the hole transport layer;

forming an electron transport layer on the light emitting layer;

and forming a second electrode on the electron transport layer.

12. The method of claim 11, wherein the step of forming a hole transport layer on the first electrode comprises:

forming a common layer on the first electrode;

forming a blue light hole transport layer opposite to the opening on the common layer, and forming a blue light emitting layer on the blue light hole transport layer;

forming a red light hole transport layer opposite to the opening on the common layer, and forming a red light emitting layer on the red light hole transport layer;

and forming a green light hole transport layer on the common layer, wherein the green light hole transport layer is opposite to the opening, and forming a green light emitting layer on the green light hole transport layer, wherein at least one of the red light hole transport layer, the green light hole transport layer and the blue light hole transport layer is formed by the first material and the second material, the hole mobility of the first material is greater than that of the second material, and the absolute value of the HOMO level of the first material is smaller than that of the second material.

13. The method according to claim 12, wherein the step of forming a green light hole transport layer on the common layer so as to be opposed to the opening and forming a green light emitting layer on the green light hole transport layer comprises:

forming a first layer on the common layer, the first layer comprising the first material;

forming a second layer on the first layer, the second layer comprising the second material;

the green light emitting layer is formed on the second layer.

14. The method of claim 12, wherein the step of forming a green hole transport layer on the common layer opposite the opening comprises:

and forming a green light hole transport layer doped by the first material and the second material on the common layer.

15. A display device characterized by comprising the display panel according to any one of claims 1 to 10.

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