Display panel and display apparatus

Abstract

Disclosed in the present application are a display panel and a display apparatus. A light-emitting device layer comprises an n-type charge generation layer and a p-type charge generation layer; the light-emitting device layer has a first operating voltage at a preset current density, and the light-emitting device layer has a second operating voltage after operating at the preset current density and a first preset temperature for a preset time, wherein the absolute value of the difference value of the first operating voltage and the second operating voltage is a1, a1 is less than or equal to 1V, and the first preset temperature is greater than or equal to 50℃.

Description

Display panel and display device Technical Field

[0001] The present application relates to the field of display technology, and in particular to a display panel and a display device. Background Art

[0002] Compared with inorganic semiconductor materials, organic semiconductor materials have low preparation costs, good controllability and excellent optoelectronic properties. Organic light-emitting diodes (OLEDs) have great potential in the application of optoelectronic devices in display, lighting and other aspects.

[0003] With the development of flat-panel display technology, customer requirements for display stability have gradually increased. In recent years, OLED displays have experienced rapid global growth, and OLED display technology has also been continuously refined. With the improvement of OLED technology capabilities and process improvements, the application of OLED displays has gradually expanded to medium and large sizes. In the medium and large-sized OLED display market, the stability requirements for displays are even higher, especially in terms of lifespan and temperature stability.

[0004] Although OLED devices have great advantages in terms of efficiency and lifespan, medium and large-sized products generate severe heat and face significant heat dissipation issues in module forms that compress product stacking space. If the high-temperature stability of OLED devices is insufficient, it can easily lead to unstable display and poor display effects. Technical Solutions

[0005] The embodiments of the present application provide a display panel and a display device, which can improve the high-temperature stability of the light-emitting device layer and improve the display stability and display effect of the display panel.

[0006] An embodiment of the present application provides a display panel, comprising a light-emitting device layer, wherein the light-emitting device layer comprises:

[0007] anode;

[0008] A first light-emitting layer is provided on one side of the anode;

[0009] An n-type charge generation layer is provided on a side of the first light-emitting layer away from the anode, the n-type charge generation layer comprising: an electron transport material and an n-type doping material;

[0010] A p-type charge generation layer is provided on a side of the n-type charge generation layer away from the first light-emitting layer, the p-type charge generation layer comprising: a hole transport material and a p-type doping material;

[0011] a second light-emitting layer, disposed on a side of the p-type charge generation layer away from the n-type charge generation layer;

[0012] a cathode, disposed on a side of the second light-emitting layer away from the p-type charge generation layer;

[0013] In which, the light-emitting device layer has a first operating voltage at a preset current density, and the light-emitting device layer has a second operating voltage at the preset current density and after working for a preset time at a first preset temperature. The absolute value of the difference between the first operating voltage and the second operating voltage is a1, a1 is less than or equal to 1V, and the first preset temperature is greater than or equal to 50°C.

[0014] According to the above-mentioned purpose of the present application, an embodiment of the present application further provides a display device, wherein the display device includes a display panel, wherein the display panel includes a light-emitting device layer, wherein the light-emitting device layer includes:

[0015] anode;

[0016] A first light-emitting layer is provided on one side of the anode;

[0017] An n-type charge generation layer is provided on a side of the first light-emitting layer away from the anode, the n-type charge generation layer comprising: an electron transport material and an n-type doping material;

[0018] A p-type charge generation layer is provided on a side of the n-type charge generation layer away from the first light-emitting layer, the p-type charge generation layer comprising: a hole transport material and a p-type doping material;

[0019] a second light-emitting layer, disposed on a side of the p-type charge generation layer away from the n-type charge generation layer;

[0020] a cathode, disposed on a side of the second light-emitting layer away from the p-type charge generation layer;

[0021] In which, the light-emitting device layer has a first operating voltage at a preset current density, and the light-emitting device layer has a second operating voltage at the preset current density and after working for a preset time at a first preset temperature. The absolute value of the difference between the first operating voltage and the second operating voltage is a1, a1 is less than or equal to 1V, and the first preset temperature is greater than or equal to 50°C.

[0022] Beneficial effects of the present application: In the display panel provided by the present application, after the light-emitting device layer operates at a high temperature greater than or equal to 50°C and a preset current density for a preset time, the absolute value of the difference between its second operating voltage and the first operating voltage at the preset current density is less than or equal to 1V, thereby making the light-emitting device layer have better stability at high temperatures, thereby improving the stability and display effect of the display panel. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG1 is a schematic structural diagram of a light-emitting device layer in a display panel provided in an embodiment of the present application;

[0024] FIG2 is a schematic structural diagram of a display panel provided in an embodiment of the present application;

[0025] FIG3 is another schematic diagram of the structure of a light-emitting device layer in a display panel provided in an embodiment of the present application;

[0026] FIG4 is another schematic diagram of the structure of the light-emitting device layer in the display panel provided in an embodiment of the present application;

[0027] FIG5 is a schematic diagram of the structure of a reactive device provided in an embodiment of the present application;

[0028] FIG6 is another schematic diagram of the structure of the light-emitting device layer in the display panel provided in an embodiment of the present application. Modes for Carrying Out the Invention

[0029] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0030] The disclosure below provides many different embodiments or examples for realizing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or reference letters in different examples, and such repetition is for the purpose of simplicity and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those of ordinary skill in the art will appreciate the application of other processes and / or the use of other materials.

[0031] 1 and 2 , the display panel provided in the embodiment of the present application includes a light-emitting device layer 10 , and the light-emitting device layer 10 includes an anode 11 , a first light-emitting layer 12 , an n-type charge generation layer 13 , a p-type charge formation layer 14 , a second light-emitting layer 15 and a cathode 16 .

[0032] Among them, the first light-emitting layer 12 is arranged on one side of the anode 11; the n-type charge generation layer 13 is arranged on the side of the first light-emitting layer 12 away from the anode 11, and the n-type charge generation layer 13 includes an electron transport material and an n-type dopant material 131; the p-type charge generation layer 14 is arranged on the side of the n-type charge generation layer 13 away from the first light-emitting layer 12, and the p-type charge generation layer 14 includes a hole transport material and a p-type dopant material 141; the second light-emitting layer 15 is arranged on the side of the p-type charge generation layer 14 away from the n-type charge generation layer 13; and the cathode 16 is arranged on the side of the second light-emitting layer 15 away from the p-type charge generation layer 14.

[0033] Furthermore, the light-emitting device layer 10 has a first operating voltage at a preset current density, and the light-emitting device layer 10 has a second operating voltage at a preset current density and at a first preset temperature after operating for a preset time. The absolute value of the difference between the first operating voltage and the second operating voltage is a1, a1 is less than or equal to 1V, and the first preset temperature is greater than or equal to 50°C.

[0034] During the application process, since the n-type charge generation layer 13 and the p-type charge generation layer 14 are adjacent, under high temperature conditions, the n-type dopant material 131 in the n-type charge generation layer 13 and the n-type dopant material 131 in the p-type charge generation layer 14 will undergo an electrochemical reaction at the interface, thereby damaging the p-type dopant material 141, causing structural defects in the p-type charge generation layer 14, and thus causing a sharp increase in the operating voltage of the light-emitting device layer 10. In the display panel provided in the embodiment of the present application, after the light-emitting device layer 10 operates at a high temperature of greater than or equal to 50°C and a preset current density for a preset time, the absolute value of the difference between its second operating voltage and the first operating voltage at the preset current density is less than or equal to 1V, thereby making the light-emitting device layer have good stability at high temperatures, effectively reducing the reactivity at the interface between the n-type charge generation layer 13 and the p-type charge generation layer 14 at high temperatures, and improving the stability and display effect of the display panel.

[0035] In one embodiment of the present application, the light-emitting device layer has a third operating voltage after operating at the preset current density and the second preset temperature for the preset time, the absolute value of the difference between the first operating voltage and the third operating voltage is a2, a2 ​​is less than a1, and the second preset temperature is less than 50°C.

[0036] In one embodiment of the present application, the second operating voltage is greater than the first operating voltage, and the third operating voltage is greater than the first operating voltage.

[0037] In one embodiment of the present application, the preset time is greater than 0 and less than or equal to 120 hours, and the preset current density is greater than or equal to 5 mA / cm 2 .

[0038] In one embodiment of the present application, the absolute value of the difference between the second operating voltage and the first operating voltage is less than or equal to 0.5V.

[0039] In one embodiment of the present application, the absolute value of the difference between the second operating voltage and the first operating voltage decreases as the doping concentration of the p-type doping material in the p-type charge generation layer decreases.

[0040] In one embodiment of the present application, the light-emitting device layer further includes a hole injection layer disposed between the anode and the first light-emitting layer, wherein a first doping material is distributed in the hole injection layer, and the first doping material is different from the p-type doping material.

[0041] In one embodiment of the present application, the light-emitting device layer also includes a hole injection layer arranged between the anode and the first light-emitting layer, and a first doping material is distributed in the hole injection layer. The first doping material is the same as the p-type doping material, and the doping concentration of the first doping material in the hole injection layer is different from the doping concentration of the p-type doping material in the p-type charge generation layer.

[0042] In one embodiment of the present application, the mass percentage of the p-type doping material in the p-type charge generation layer is greater than or equal to 0.1% and less than or equal to 20%.

[0043] In one embodiment of the present application, the light-emitting device layer further includes a first hole transport layer disposed between the p-type charge generation layer and the second light-emitting layer, the lowest unoccupied orbital energy level of the p-type doping material is greater than -5.5 eV, and the highest occupied orbital energy level of the material of the first hole transport layer is greater than -6.5 eV.

[0044] In one embodiment of the present application, a difference between the lowest unoccupied orbital energy level of the p-type doping material and the highest occupied orbital energy level of the material of the first hole transport layer is less than 1 eV.

[0045] In one embodiment of the present application, the reddest absorption peak wavelength of the p-type doping material is greater than 400 nm, and the fluorescence emission peak wavelength of the p-type doping material is greater than 500 nm.

[0046] In one embodiment of the present application, the light-emitting device layer further includes a buffer layer disposed between the n-type charge generation layer and the p-type charge generation layer, and a material of the buffer layer includes at least one of an organic material and a metal material.

[0047] Specifically, in one embodiment, please continue to combine Figures 1 and 2. The display panel provided in the embodiment of the present application includes a substrate 20, a thin film transistor layer 30 arranged on the substrate 20, and a light-emitting device layer 10 arranged on the side of the thin film transistor layer 30 away from the substrate 20.

[0048] The thin film transistor layer 30 is provided with a plurality of thin film transistors, and the light emitting device layer 10 can be connected to the thin film transistors. The thin film transistors can be used as switches to control the on and off of signals input into the light emitting device layer 10 .

[0049] Specifically, the light-emitting device layer 10 includes an anode 11, a first light-emitting layer 12 arranged on one side of the anode 11, an n-type charge generation layer 13 arranged on the side of the first light-emitting layer 12 away from the anode 11, a p-type charge generation layer 14 arranged on the side of the n-type charge generation layer 13 away from the first light-emitting layer 12, and a second light-emitting layer 15 arranged on the side of the p-type charge generation layer 14 away from the n-type charge generation layer 13, and a cathode 16 arranged on the side of the second light-emitting layer 15 away from the p-type charge generation layer 14.

[0050] The anode 11 is disposed on a side of the light emitting device layer 10 close to the thin film transistor layer 30 , and the anode 11 can be connected to the thin film transistor in the thin film transistor layer 30 to access signals.

[0051] In one embodiment, please refer to Figures 1 and 3, the light-emitting device layer 10 also includes a hole injection layer 171 arranged on the side of the anode 11 close to the first light-emitting layer 12, and a second hole transport layer 172 arranged between the hole injection layer 171 and the first light-emitting layer 12, a first electron transport layer 181 arranged between the first light-emitting layer 12 and the n-type charge generation layer 13, a first hole transport layer 173 arranged between the p-type charge generation layer 14 and the second light-emitting layer 15, a second electron transport layer 182 arranged on the side of the second light-emitting layer 15 close to the cathode 16, and an electron injection layer 183 arranged between the second electron transport layer 182 and the cathode 16.

[0052] It should be noted that the display panel provided in the embodiment of the present application is a stacked OLED display panel, that is, the light-emitting device layer 10 has multiple light-emitting layers, and the embodiment of the present application takes two light-emitting layers as an example for explanation, and an n-type charge generation layer and a p-type charge generation layer are provided between the two adjacent light-emitting layers.

[0053] In addition, an electron blocking layer can be provided on the side of the first light-emitting layer 12 close to the anode 11, and a hole blocking layer can be provided on the side close to the cathode 16. Similarly, an electron blocking layer can be provided on the side of the second light-emitting layer 15 close to the anode 11, and a hole blocking layer can be provided on the side close to the cathode 16.

[0054] In one embodiment, the material of the anode 11 may include ITO material, and the material of the cathode 16 may include at least one of Mg and Ag.

[0055] Furthermore, n-type charge generation layer 13 can be formed by doping an electron transport material with an n-type dopant material 131, while p-type charge generation layer 14 can be formed by doping a hole transport material with a p-type dopant material 141. In one embodiment, n-type dopant material 131 can include active alkali metals, alkaline earth metals, and salts thereof, such as lithium, sodium, potassium, cesium, magnesium, calcium, strontium, barium, ytterbium, lithium fluoride, sodium fluoride, lithium carbonate, cesium carbonate, lithium nitride, etc., while p-type dopant material 141 can include at least one of a metal material and an organic material. Thus, n-type dopant material 131 is distributed in at least n-type charge generation layer 13, while p-type dopant material 141 is distributed in p-type charge generation layer 14.

[0056] In one embodiment, the mass percentage of the p-type dopant material 141 in the p-type charge generation layer 14 is greater than or equal to 0.1% and less than or equal to 20%, for example, it can be 0.1%, 2%, 4%, 6%, 8%, 12%, 14%, 16%, 18%, or 20%; the mass percentage of the n-type dopant material 131 in the n-type charge generation layer 13 is greater than or equal to 0.1% and less than or equal to 20%, for example, it can be 0.1%, 2%, 4%, 6%, 8%, 12%, 14%, 16%, 18%, or 20%.

[0057] Furthermore, the light-emitting device layer 10 has a first operating voltage at a preset current density, and the light-emitting device layer 10 has a second operating voltage after operating at a preset current density and a first preset temperature for a preset time, and the absolute value of the difference between the first operating voltage and the second operating voltage is a1, a1 is less than or equal to 1V, and the first preset temperature is greater than or equal to 50°C; thereby, the light-emitting device layer has better stability at high temperatures, effectively reducing the reaction activity at the interface between the n-type charge generation layer 13 and the p-type charge generation layer 14 at high temperatures, and improving the stability and display effect of the display panel.

[0058] In one embodiment, the light-emitting device layer 10 has a third operating voltage after operating at a preset current density and a second preset temperature for a preset time, the absolute value of the difference between the first operating voltage and the third operating voltage is a2, a2 ​​is less than a1, and the second preset temperature is less than 50°C; that is, the display panel provided in the embodiment of the present application has good stability also at non-high temperatures, and the reaction activity at the interface between the n-type charge generation layer 13 and the p-type charge generation layer 14 at high temperatures below 50°C is low, and the stability of the display panel is good.

[0059] It should be noted that, as the temperature and operating time increase, the operating voltage of the light-emitting device layer 10 will also increase. Therefore, the second operating voltage is greater than the first operating voltage, and the third operating voltage is greater than the first operating voltage.

[0060] In one embodiment, the preset current density may be greater than or equal to 5 mA / cm 2 The preset temperature can be greater than or equal to 50°C, the preset power-on time can be greater than 1 and less than or equal to 120h; further, the preset current density can also be less than or equal to 10mA / cm 2 , for example, 5 mA / cm 2 , 6mA / cm 2 , 7mA / cm 2 , 8mA / cm 2 , 9mA / cm 2 , or 10mA / cm 2 ; The preset temperature can be greater than or equal to 110℃.

[0061] In an embodiment of the present application, the difference between the second operating voltage and the first operating voltage is less than or equal to 1V, that is, under the same preset current density, the difference between the operating voltage of the light-emitting device layer 10 at a preset temperature and a preset power-on time and the initial operating voltage needs to be less than or equal to 1V, thereby avoiding the operating voltage of the light-emitting device layer 10 from rising sharply due to high temperature, that is, the present application can improve the high-temperature stability of the light-emitting device layer 10 and improve the display stability and display effect of the display panel.

[0062] Further preferably, the difference between the second operating voltage and the first operating voltage is less than or equal to 0.5V.

[0063] It should be noted that p-type doping material 141 is distributed in the p-type charge generation layer 14. After verification, the embodiment of the present application found that the difference between the second operating voltage and the first operating voltage decreases with the decrease of the doping concentration of the p-type doping material 141 in the p-type charge generation layer 14. That is, the embodiment of the present application can reduce the doping concentration of the p-type doping material 141 in the p-type charge generation layer 14 to reduce the reaction activity between the n-type doping material 131 and the p-type doping material 141 at high temperature, thereby improving the high-temperature stability of the light-emitting device layer 10 and improving the stability and display effect of the display panel.

[0064] In the embodiment of the present application, the hole injection layer 171 may be a hole transport material doped with a first doping material, and the electron injection layer 183 may be an electron transport material doped with a second doping material, and the first doping material may be the same as or different from the p-type doping material 141, and the second doping material may be the same as or different from the n-type doping material 131.

[0065] Among them, when the first doping material is different from the p-type doping material 141, the reaction activity between the n-type doping material 131 and the p-type doping material 141 at high temperature can be controlled by controlling the material selection of the p-type doping material 141; when the first doping material is different from the p-type doping material 141, the doping concentration of the p-type doping material 141 in the p-type charge generation layer 14 can be controlled to control the reaction activity between the n-type doping material 131 and the p-type doping material 141 at high temperature.

[0066] In one embodiment, the doping concentration of the first doping material in the hole injection layer 171 is different from the doping concentration of the p-type doping material 141 in the p-type charge generation layer 14. For example, the doping concentration of the first doping material in the hole injection layer 171 may be 3%, while the doping concentration of the p-type doping material 141 in the p-type charge generation layer 14 may be 5%.

[0067] It should be noted that in the embodiment of the present application, the reaction activity between the n-type doping material 131 and the p-type doping material 141 at high temperature can be reduced by selecting the p-type doping material 141, so that the difference between the second operating voltage and the first operating voltage is less than or equal to 1V.

[0068] Furthermore, the embodiment of the present application can also verify the energy level and other properties of the p-type doping material 141 to obtain a suitable material that meets the requirement of low high-temperature reactivity.

[0069] In one embodiment, the lowest unoccupied orbital energy level of the p-type dopant material 141 is greater than -5.5 eV, the highest occupied orbital energy level of the material of the first hole transport layer is greater than -6.5 eV, and the difference between the lowest unoccupied orbital energy level of the p-type dopant material 141 and the highest occupied orbital energy level of the material of the first hole transport layer is less than 1 eV to facilitate charge separation.

[0070] In one embodiment, the reddest absorption peak wavelength of the p-type dopant material 141 is greater than 400 nm, the fluorescence emission peak wavelength of the p-type dopant material 141 is greater than 500 nm, and the refractive index of the p-type dopant material 141 is greater than or equal to 1.5 and less than or equal to 1.8.

[0071] In one embodiment, the p-type doping material 141 may include a dicyanomethane compound, and the dicyanomethane compound contains at least one dicyanomethylene group.

[0072] Specifically, the p-type doping material 141 may be selected from at least one compound having a structure described by the following formula (1):

[0073] wherein n is an integer greater than 0, and ring Ca can be selected from a substituted or unsubstituted aryl group having 3 to 60 carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 60 carbon atoms, or a group consisting of a plurality of the above substituted or unsubstituted aryl groups having 3 to 60 carbon atoms or substituted or unsubstituted heteroaryl groups having 2 to 60 carbon atoms connected to each other.

[0074] Furthermore, the compound represented by formula (1) may further include the following formulas (1-1), (1-2), (1-3), and (1-4):

[0075] Wherein, formula (1-1) may include compounds represented by the following formulas (1-1a) to (1-1e):

[0076] Among them, X101 to X104 in formula (1-1a), X111 to X116 in formula (1-1b), X121 to X128 in formula (1-1c), X131 to X136 in formula (1-1d), and X141 to X148 in formula (1-1e) can each independently be N or CRa; when X101 to X148 are each independently CRa, each CRa can be the same or different. Each CRa is independently selected from hydrogen, deuterium, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 50 carbon atoms, a substituted or unsubstituted alkylsilyl group having 1 to 30 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 50 carbon atoms, a cyano group, a nitro group, and a halogen group. If the above substituents are in adjacent positions, for example, when X101 and X102 are both CRa, their Ra groups may be further bonded to form a ring structure.

[0077] Formula (1-2) may include compounds represented by the following formulas (1-2a) to (1-2g):

[0078] Among them, X201 to X204 in formula (1-2a), X211 to X216 in formula (1-2b), X221 to X226 in formula (1-2c), X231 to X238 in formula (1-2d), X241 to X248 in formula (1-2e), X251 to X254 in formula (1-2f), and X261 to X264 in formula (1-2g) can each independently be N or CRa; when X201 to X264 are each independently CRa, each CRa can be the same or different. Each CRa is independently selected from hydrogen, deuterium, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 50 carbon atoms, a substituted or unsubstituted alkylsilyl group having 1 to 30 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 50 carbon atoms, a cyano group, a nitro group, and a halogen group. If the above substituents are in adjacent positions, their Ra groups may be further bonded to form a ring structure.

[0079] In formula (1-2f), Y251 and Y252, and in formula (1-2g), Y261 may be independently O or S or NRb or CRcRd; and when they are independently NRb or CRcRd, each Rb, Rc and Rd may be the same or different. Each Rb, Rc and Rd are independently selected from hydrogen, deuterium, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 50 carbon atoms, a substituted or unsubstituted alkylsilyl group having 1 to 30 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 50 carbon atoms, a cyano group, a nitro group, or a halogen group. If the above substituents are in adjacent positions, their Rb, Rc and Rd, as well as adjacent Ra groups, can be bonded to each other to form a ring structure.

[0080] Formula (1-3) may further include compounds represented by the following formulas (1-3a) and (1-3b):

[0081] Wherein, X301 to X304 in formula (1-3a) and X311 to X316 in formula (1-3b) can each independently be N or CRa; when X201 to X264 are each independently CRa, each CRa can be the same or different. Each CRa is independently selected from hydrogen, deuterium, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 50 carbon atoms, a substituted or unsubstituted alkylsilyl group having 1 to 30 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 50 carbon atoms, a cyano group, a nitro group, and a halogen group. If the above substituents are in adjacent positions, their Ra groups can be bonded to each other to form a ring structure.

[0082] Formula (1-4) may further include compounds represented by the following formulas (1-4a) to (1-4b):

[0083] In formula (1-4a), X301 to X306, and in formula (1-4b), X411 to X416 can each independently be N or CRa; when X201 to X264 are each independently CRa, each CRa can be the same or different. Each CRa is independently selected from hydrogen, deuterium, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 50 carbon atoms, a substituted or unsubstituted alkylsilyl group having 1 to 30 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 50 carbon atoms, a cyano group, a nitro group, and a halogen group. If the above substituents are in adjacent positions, their Ra groups can be bonded to each other to form a ring structure.

[0084] As mentioned above, the p-type doping material 141 provided in the embodiment of the present application can be selected from at least one of PD-01 to PD-141:

[0085] In one embodiment, the hole transport material in the p-type charge generation layer 14 provided in the embodiment of the present application may include an aromatic amine compound and contain at least one aromatic amine group, and the hole transport material may include at least one of the compounds of the following formula (2):

[0086] R201 to R207 are independently selected from hydrogen, deuterium, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 50 carbon atoms, a substituted or unsubstituted alkylsilyl group having 1 to 30 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 50 carbon atoms, a cyano group, a nitro group, and a halogen group. If the above substituents are in adjacent positions, such as R203 and R204, they may be bonded to form a ring structure.

[0087] For example, the hole transport material in the p-type charge generation layer 14 may be selected from at least one of the following compounds:

[0088] It is understood that, in the embodiment of the present application, the hole transport material in the first hole transport layer 173 and the second hole transport layer 172 may also be the same as the hole transport material in the P-type charge generation layer 14 .

[0089] In one embodiment, both the first light-emitting layer 12 and the second light-emitting layer 15 may be formed by doping a blue light shell material into a blue light host material, wherein the blue light host material may include at least one of the following compounds:

[0090] The blue light guest material may include at least one of the following compounds:

[0091] In one embodiment, the electron transport material in the first electron transport layer 181 , the second electron transport layer 182 , and the electron injection layer 183 may include at least one of the following compounds:

[0092] In one embodiment, the electron transport material in the n-type charge generation layer 13 may include at least one of the following compounds: .

[0093] In another embodiment of the present application, referring to Figures 1 and 4 , this embodiment differs from the embodiment shown in Figure 3 in that a buffer layer 19 is provided between n-type charge generation layer 13 and p-type charge generation layer 14. The material of buffer layer 19 may include at least one of an organic material and a metallic material. In this embodiment of the present application, buffer layer 19 serves to separate n-type charge generation layer 13 and p-type charge generation layer 14, thereby reducing the reactivity between n-type dopant material 131 and p-type dopant material 141 at high temperatures.

[0094] In one embodiment, the material of the buffer layer 19 may include at least one of a hole transport layer material, an electron transport layer material, an organic material used in the n-type charge generation layer 13 , aluminum, silver, and zinc oxide.

[0095] To sum up, in the embodiment of the present application, the difference between the second operating voltage and the first operating voltage of the light-emitting device layer 10 can be controlled to reduce the reaction activity between the n-type doping material 131 and the p-type doping material 141 at high temperature, thereby improving the high-temperature stability of the light-emitting device layer 10 and improving the stability of the display panel and the display effect.

[0096] Furthermore, to verify the effect of the embodiment of the present application on reducing the reactivity between the n-type doping material 131 and the p-type doping material 141 at high temperature, the embodiment of the present application provides a reactive device to verify the operating voltage under different conditions.

[0097] It can be understood that the reactive device is not a functional device in the display panel, but a device provided in the embodiment of the present application to verify the high-temperature reactive activity.

[0098] Please refer to Figure 5, the reactive device includes a first electron transport layer 181, an n-type charge generation layer 13, a p-type charge generation layer 14, a first hole transport layer 173, an electron injection layer 183 and a cathode 16 arranged in sequence on the anode 11, that is, the reactive device removes the first light-emitting layer 12, the second light-emitting layer 15 and the second electron transport layer 182 and the second hole transport layer 172 and the hole injection layer 171 adjacent to the above-mentioned light-emitting layers relative to the light-emitting device layer 10 shown in Figure 3.

[0099] Specifically, the embodiments of the present application provide comparative example 1, comparative example 2, embodiment 1 and embodiment 2.

[0100] Among them, in comparative example 1, the anode 11 is prepared using ITO material; the material of the first electron transport layer 181 includes Liq and ET5, wherein the mass proportion of Liq is 50%, and the thickness of the first electron transport layer 181 is 10nm; the material of the n-type charge generation layer 13 includes Yb and E19, the mass proportion of Yb is 5%, and the thickness of the n-type charge generation layer 13 is 10nm, the material of the p-type charge generation layer 14 includes PD-a1 and TAPC, the mass proportion of PD-a1 is 5%, and the thickness of the p-type charge generation layer 14 is 10nm; the material of the first hole transport layer 173 includes TAPC, and the thickness of the first hole transport layer 173 is 10nm; the material of the electron injection layer 183 includes Yb, and the thickness of the electron injection layer 183 is 1nm; the material of the cathode 16 includes Mg and Ag, the mass proportion of Mg is 10%, and the thickness of the cathode 16 is 20nm.

[0101] In the second comparative document, the anode 11 is made of ITO material; the material of the first electron transport layer 181 includes Liq and ET5, wherein the mass proportion of Liq is 50%, and the thickness of the first electron transport layer 181 is 10nm; the material of the n-type charge generation layer 13 includes Yb and E19, the mass proportion of Yb is 5%, and the thickness of the n-type charge generation layer 13 is 10nm, the material of the p-type charge generation layer 14 includes PD-a2 and TAPC, the mass proportion of PD-a2 is 5%, and the thickness of the p-type charge generation layer 14 is 10nm; the material of the first hole transport layer 173 includes TAPC, and the thickness of the first hole transport layer 173 is 10nm; the material of the electron injection layer 183 includes Yb, and the thickness of the electron injection layer 183 is 1nm; the material of the cathode 16 includes Mg and Ag, the mass proportion of Mg is 10%, and the thickness of the cathode 16 is 20nm.

[0102] In Example 1, the anode 11 is made of ITO material; the material of the first electron transport layer 181 includes Liq and ET5, wherein the mass proportion of Liq is 50%, and the thickness of the first electron transport layer 181 is 10 nm; the material of the n-type charge generation layer 13 includes Yb and E19, the mass proportion of Yb is 5%, and the thickness of the n-type charge generation layer 13 is 10 nm, the material of the p-type charge generation layer 14 includes PD-113 and TAPC, the mass proportion of PD-113 is 5%, and the thickness of the p-type charge generation layer 14 is 10 nm; the material of the first hole transport layer 173 includes TAPC, and the thickness of the first hole transport layer 173 is 10 nm; the material of the electron injection layer 183 includes Yb, and the thickness of the electron injection layer 183 is 1 nm; the material of the cathode 16 includes Mg and Ag, the mass proportion of Mg is 10%, and the thickness of the cathode 16 is 20 nm.

[0103] In Example 2, the anode 11 is made of ITO material; the material of the first electron transport layer 181 includes Liq and ET5, wherein the mass proportion of Liq is 50%, and the thickness of the first electron transport layer 181 is 10 nm; the material of the n-type charge generation layer 13 includes Yb and E19, the mass proportion of Yb is 5%, and the thickness of the n-type charge generation layer 13 is 10 nm, the material of the p-type charge generation layer 14 includes PD-114 and TAPC, the mass proportion of PD-114 is 5%, and the thickness of the p-type charge generation layer 14 is 10 nm; the material of the first hole transport layer 173 includes TAPC, and the thickness of the first hole transport layer 173 is 10 nm; the material of the electron injection layer 183 includes Yb, and the thickness of the electron injection layer 183 is 1 nm; the material of the cathode 16 includes Mg and Ag, the mass proportion of Mg is 10%, and the thickness of the cathode 16 is 20 nm.

[0104] The structural formulas of PD-a1 and PD-a2 are as follows:

[0105] Under high vacuum conditions, the reactive devices shown in Comparative Example 1, Comparative Example 2, Example 1, and Example 2 were respectively formed. The specific test verification process includes:

[0106] First, at room temperature, the reactive device was charged at 10 mA / cm 2 The first working voltage V1 was measured at a current density of 10 mA / cm2, and then the working voltage V1 was measured at 110 °C and 10 mA / cm2. 2 After operating continuously for 120 hours at the current density, the second operating voltage V2 is measured. ΔV(V2-V1) is positively correlated with the reaction activity between the n-type dopant material 131 and the p-type dopant material 141 at high temperature. The data are shown in Table 1 below.

[0107] Table 1 Working voltage data table

[0108] It can be seen from Table 1 above that Example 1 and Example 2 use the materials PD-113 and PD114 of the p-type charge generation layer 14 provided in the embodiments of the present application. Compared with the comparative example, △V is significantly reduced and is less than or equal to 3V, that is, the difference between the second operating voltage and the first operating voltage is reduced, which further indicates that the reaction activity between the n-type doping material 131 and the p-type doping material 141 at high temperature in Example 1 and Example 2 can be effectively reduced.

[0109] Furthermore, the embodiments of the present application further provide comparative example three, comparative example four, embodiment three and embodiment four to verify the effect of reducing the reaction activity between the n-type doping material 131 and the p-type doping material 141 at high temperature when the above materials are applied to the light-emitting device layer shown in Figure 6.

[0110] Among them, in comparative example 3, the anode 11 is made of ITO; the material of the hole injection layer 171 includes PD-a2 and TAPC, and the mass percentage content of PD-a2 is 3%; and the thickness of the hole injection layer 171 is 10nm; the material of the second hole transport layer 172 includes TAPC, and the thickness of the second hole transport layer 172 is 25nm; the material of the first electron blocking layer 184 includes TCTA, and the thickness of the first electron blocking layer 184 is 5nm; the material of the first light-emitting layer 12 includes BD3 and BH16, B The mass percentage content of D3 is 2%, and the thickness of the first light-emitting layer 12 is 20nm; the material of the first hole blocking layer 174 is ET6, and the thickness of the first hole blocking layer 174 is 5nm; the material of the first electron transport layer 181 includes Liq and ET5, the mass percentage content of Liq is 50%, and the thickness of the first electron transport layer 181 is 20nm; the material of the n-type charge generation layer 13 includes Yb and E19, the mass percentage content of Yb is 5%, and the thickness of the n-type charge generation layer 13 is 10nm; The material of the p-type charge generation layer 14 includes PD-a1 and TAPC, the mass percentage content of PD-a1 is 5%, and the thickness of the p-type charge generation layer 14 is 10nm; the material of the second hole transport layer 172 includes TAPC, and the thickness of the second hole transport layer 172 is 30nm; the material of the second electron blocking layer 185 includes TCTA, and the thickness of the second electron blocking layer 185 is 5nm; the material of the second light-emitting layer 15 includes BD3 and BH16, the mass percentage content of BD3 is 2%, and the second light-emitting layer 1 5 has a thickness of 20 nm; the material of the second hole blocking layer 175 includes ET6, and the thickness of the second hole blocking layer 175 is 5 nm; the material of the second electron transport layer 182 includes Liq and ET5, the mass percentage content of Liq is 50%, and the thickness of the second electron transport layer 182 is 30 nm; the material of the electron injection layer 183 includes Yb, and the thickness of the electron injection layer 183 is 1 nm; the material of the cathode 16 includes Mg and Ag, the mass percentage content of Mg is 10%, and the thickness of the cathode 16 is 15 nm.

[0111] In comparative example 4, the anode 11 is made of ITO; the material of the hole injection layer 171 includes PD-a2 and TAPC, the mass percentage content of PD-a2 is 3%; and the thickness of the hole injection layer 171 is 10nm; the material of the second hole transport layer 172 includes TAPC, and the thickness of the second hole transport layer 172 is 25nm; the material of the first electron blocking layer 184 includes TCTA, and the thickness of the first electron blocking layer 184 is 5nm; the material of the first light-emitting layer 12 includes BD3 and BH16, BD3 The mass percentage content is 2%, and the thickness of the first light-emitting layer 12 is 20nm; the material of the first hole blocking layer 174 is ET6, and the thickness of the first hole blocking layer 174 is 5nm; the material of the first electron transport layer 181 includes Liq and ET5, the mass percentage content of Liq is 50%, and the thickness of the first electron transport layer 181 is 20nm; the material of the n-type charge generation layer 13 includes Yb and E19, the mass percentage content of Yb is 5%, and the thickness of the n-type charge generation layer 13 is 10nm; the material of the p-type The material of the charge generation layer 14 includes PD-a2 and TAPC, the mass percentage content of PD-a2 is 5%, and the thickness of the p-type charge generation layer 14 is 10nm; the material of the second hole transport layer 172 includes TAPC, and the thickness of the second hole transport layer 172 is 30nm; the material of the second electron blocking layer 185 includes TCTA, and the thickness of the second electron blocking layer 185 is 5nm; the material of the second light-emitting layer 15 includes BD3 and BH16, the mass percentage content of BD3 is 2%, and the second light-emitting layer 1 5 has a thickness of 20 nm; the material of the second hole blocking layer 175 includes ET6, and the thickness of the second hole blocking layer 175 is 5 nm; the material of the second electron transport layer 182 includes Liq and ET5, the mass percentage content of Liq is 50%, and the thickness of the second electron transport layer 182 is 30 nm; the material of the electron injection layer 183 includes Yb, and the thickness of the electron injection layer 183 is 1 nm; the material of the cathode 16 includes Mg and Ag, the mass percentage content of Mg is 10%, and the thickness of the cathode 16 is 15 nm.

[0112] In Example 3, the anode 11 is made of ITO; the material of the hole injection layer 171 includes PD-a2 and TAPC, and the mass percentage content of PD-a2 is 3%; and the thickness of the hole injection layer 171 is 10nm; the material of the second hole transport layer 172 includes TAPC, and the thickness of the second hole transport layer 172 is 25nm; the material of the first electron blocking layer 184 includes TCTA, and the thickness of the first electron blocking layer 184 is 5nm; the material of the first light-emitting layer 12 includes BD3 and BH16, BD3 The mass percentage content of Liq is 2%, and the thickness of the first light-emitting layer 12 is 20nm; the material of the first hole blocking layer 174 is ET6, and the thickness of the first hole blocking layer 174 is 5nm; the material of the first electron transport layer 181 includes Liq and ET5, the mass percentage content of Liq is 50%, and the thickness of the first electron transport layer 181 is 20nm; the material of the n-type charge generation layer 13 includes Yb and E19, the mass percentage content of Yb is 5%, and the thickness of the n-type charge generation layer 13 is 10nm; the material of the p-type charge generation layer 13 includes Yb and E19, the mass percentage content of Yb is 5%, and the thickness of the n-type charge generation layer 13 is 10nm; The material of the p-type charge generation layer 14 includes PD-113 and TAPC, the mass percentage content of PD-113 is 5%, and the thickness of the p-type charge generation layer 14 is 10nm; the material of the second hole transport layer 172 includes TAPC, and the thickness of the second hole transport layer 172 is 30nm; the material of the second electron blocking layer 185 includes TCTA, and the thickness of the second electron blocking layer 185 is 5nm; the material of the second light-emitting layer 15 includes BD3 and BH16, the mass percentage content of BD3 is 2%, and the second light-emitting layer 1 5 has a thickness of 20 nm; the material of the second hole blocking layer 175 includes ET6, and the thickness of the second hole blocking layer 175 is 5 nm; the material of the second electron transport layer 182 includes Liq and ET5, the mass percentage content of Liq is 50%, and the thickness of the second electron transport layer 182 is 30 nm; the material of the electron injection layer 183 includes Yb, and the thickness of the electron injection layer 183 is 1 nm; the material of the cathode 16 includes Mg and Ag, the mass percentage content of Mg is 10%, and the thickness of the cathode 16 is 15 nm.

[0113] In Example 4, the anode 11 is made of ITO; the material of the hole injection layer 171 includes PD-a2 and TAPC, the mass percentage content of PD-a2 is 3%; and the thickness of the hole injection layer 171 is 10nm; the material of the second hole transport layer 172 includes TAPC, and the thickness of the second hole transport layer 172 is 25nm; the material of the first electron blocking layer 184 includes TCTA, and the thickness of the first electron blocking layer 184 is 5nm; the material of the first light-emitting layer 12 includes BD3 and BH16, BD3 The mass percentage content of Liq is 2%, and the thickness of the first light-emitting layer 12 is 20nm; the material of the first hole blocking layer 174 is ET6, and the thickness of the first hole blocking layer 174 is 5nm; the material of the first electron transport layer 181 includes Liq and ET5, the mass percentage content of Liq is 50%, and the thickness of the first electron transport layer 181 is 20nm; the material of the n-type charge generation layer 13 includes Yb and E19, the mass percentage content of Yb is 5%, and the thickness of the n-type charge generation layer 13 is 10nm; the material of the p-type charge generation layer 13 includes Yb and E19, the mass percentage content of Yb is 5%, and the thickness of the n-type charge generation layer 13 is 10nm; The material of the p-type charge generation layer 14 includes PD-114 and TAPC, the mass percentage content of PD-114 is 5%, and the thickness of the p-type charge generation layer 14 is 10nm; the material of the second hole transport layer 172 includes TAPC, and the thickness of the second hole transport layer 172 is 30nm; the material of the second electron blocking layer 185 includes TCTA, and the thickness of the second electron blocking layer 185 is 5nm; the material of the second light-emitting layer 15 includes BD3 and BH16, the mass percentage content of BD3 is 2%, and the second light-emitting layer 1 5 has a thickness of 20 nm; the material of the second hole blocking layer 175 includes ET6, and the thickness of the second hole blocking layer 175 is 5 nm; the material of the second electron transport layer 182 includes Liq and ET5, the mass percentage content of Liq is 50%, and the thickness of the second electron transport layer 182 is 30 nm; the material of the electron injection layer 183 includes Yb, and the thickness of the electron injection layer 183 is 1 nm; the material of the cathode 16 includes Mg and Ag, the mass percentage content of Mg is 10%, and the thickness of the cathode 16 is 15 nm.

[0114] Under high vacuum conditions, the reactive devices shown in Comparative Example 3, Comparative Example 4, Example 3, and Example 4 were formed respectively. The specific test verification process includes:

[0115] First, at room temperature, the reactive device was charged at 10 mA / cm 2 The first working voltage V1 was measured at a current density of 10 mA / cm2, and then the working voltage V1 was measured at 110 °C and 10 mA / cm2. 2 After continuous operation for 120 hours at the current density, the second operating voltage (i.e. the maximum operating voltage Vmax during continuous operation) is measured, and △V

[0116] There is a positive correlation between (Vmax-V1) and the reaction activity between the n-type dopant material 131 and the p-type dopant material 141 at high temperature, and the obtained data is shown in Table 2 below.

[0117] Table 2 Working voltage data table

[0118] It can be seen from Table 1 above that Example 3 and Example 4 use the materials PD-113 and PD114 of the p-type charge generation layer 14 provided in the embodiments of the present application. Compared with the comparative example, △V is significantly reduced and is less than or equal to 0.5V, that is, the difference between the second operating voltage and the first operating voltage is reduced, which further indicates that the reaction activity between the n-type doping material 131 and the p-type doping material 141 at high temperature in Example 3 and Example 4 can be effectively reduced.

[0119] In addition, an embodiment of the present application further provides a display device, which includes the display panel described in the above embodiment.

[0120] In one embodiment, the display device may include a mobile, vehicle-mounted, AR / VR, notebook, monitor, television, or other display.

[0121] It can be understood that, since the display device includes the display panel described in the above embodiment, the display device has the same beneficial effects as the display panel described in the above embodiment, which will not be described in detail here.

[0122] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0123] The above is a detailed introduction to a display panel and a display device provided in the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A display panel, the display panel includes a light-emitting device layer, and the light-emitting device layer includes: Anode; A first light-emitting layer disposed on one side of the anode; An n-type charge generation layer disposed on a side of the first light-emitting layer away from the anode, the n-type charge generation layer comprising: an electron transport material and an n-type doping material; A p-type charge generation layer disposed on a side of the n-type charge generation layer away from the first light-emitting layer, the p-type charge generation layer comprising: a hole transport material and a p-type doping material; A second light-emitting layer disposed on a side of the p-type charge generation layer away from the n-type charge generation layer; A cathode disposed on a side of the second light-emitting layer away from the p-type charge generation layer; Wherein, the light-emitting device layer has a first operating voltage at a preset current density, and has a second operating voltage after operating for a preset time at the preset current density and a first preset temperature, the absolute value of the difference between the first operating voltage and the second operating voltage is a1, a1 is less than or equal to 1V, and the first preset temperature is greater than or equal to 50°C.

2. The display panel according to claim 1, wherein, The light-emitting device layer has a third operating voltage after operating for the preset time at the preset current density and a second preset temperature, the absolute value of the difference between the first operating voltage and the third operating voltage is a2, a2 is less than a1, and the second preset temperature is less than 50°C.

3. The display panel according to claim 2, wherein, The second operating voltage is greater than the first operating voltage, and the third operating voltage is greater than the first operating voltage.

4. The display panel according to claim 2, wherein, The preset time is greater than 0 and less than or equal to 120 h, and the preset current density is greater than or equal to 5 mA / cm 2 .

5. The display panel according to claim 1, wherein, The absolute value of the difference between the second operating voltage and the first operating voltage is less than or equal to 0.5V.

6. The display panel according to claim 1, wherein, The absolute value of the difference between the second operating voltage and the first operating voltage decreases as the doping concentration of the p-type doping material in the p-type charge generation layer decreases.

7. The display panel according to claim 6, wherein, The light-emitting device layer further includes a hole injection layer disposed between the anode and the first light-emitting layer, and a first doping material is distributed in the hole injection layer, and the first doping material is different from the p-type doping material.

8. The display panel according to claim 6, wherein, The light-emitting device layer further includes a hole injection layer disposed between the anode and the first light-emitting layer, and a first doping material is distributed in the hole injection layer, the first doping material is the same as the p-type doping material, and the doping concentration of the first doping material in the hole injection layer is different from the doping concentration of the p-type doping material in the p-type charge generation layer.

9. The display panel according to claim 6, wherein, The mass percentage content of the p-type doping material in the p-type charge generation layer is greater than or equal to 0.1% and less than or equal to 20%.

10. The display panel according to claim 6, wherein, The light-emitting device layer further includes a first hole transport layer disposed between the p-type charge generation layer and the second light-emitting layer, the lowest unoccupied orbital energy level of the p-type doping material > -5.5 eV, and the highest occupied orbital energy level of the material of the first hole transport layer > -6.5 eV.

11. The display panel according to claim 10, wherein, The difference between the lowest unoccupied orbital energy level of the p-type doping material and the highest occupied orbital energy level of the material of the first hole transport layer is less than 1 eV.

12. The display panel according to claim 6, wherein, The longest absorption peak wavelength of the p-type doping material is greater than 400 nm, and the fluorescence emission peak wavelength of the p-type doping material is greater than 500 nm.

13. The display panel according to claim 1, wherein, The light-emitting device layer further includes a buffer layer disposed between the n-type charge generation layer and the p-type charge generation layer, and the material of the buffer layer includes at least one of an organic material and a metal material.

14. A display device, the display device includes a display panel, the display panel includes a light-emitting device layer, and the light-emitting device layer includes: Anode; A first light-emitting layer disposed on one side of the anode; An n-type charge generation layer disposed on a side of the first light-emitting layer away from the anode, the n-type charge generation layer including: an electron transport material and an n-type doping material; A p-type charge generation layer disposed on a side of the n-type charge generation layer away from the first light-emitting layer, the p-type charge generation layer including: a hole transport material and a p-type doping material; A second light-emitting layer disposed on a side of the p-type charge generation layer away from the n-type charge generation layer; A cathode disposed on a side of the second light-emitting layer away from the p-type charge generation layer; Wherein, the light-emitting device layer has a first operating voltage at a preset current density, and has a second operating voltage after operating for a preset time at the preset current density and a first preset temperature. The absolute value of the difference between the first operating voltage and the second operating voltage is a1, a1 is less than or equal to 1V, and the first preset temperature is greater than or equal to 50 °C.

15. The display device according to claim 14, wherein, The light-emitting device layer has a third operating voltage after operating for the preset time at the preset current density and a second preset temperature. The absolute value of the difference between the first operating voltage and the third operating voltage is a2, a2 is less than a1, and the second preset temperature is less than 50 °C.

16. The display device according to claim 15, wherein, The second operating voltage is greater than the first operating voltage, and the third operating voltage is greater than the first operating voltage.

17. The display device according to claim 15, wherein, The preset time is greater than 0 and less than or equal to 120 h, and the preset current density is greater than or equal to 5 mA / cm 2 .

18. The display device according to claim 14, wherein, The absolute value of the difference between the second operating voltage and the first operating voltage is less than or equal to 0.5V.

19. The display device according to claim 14, wherein, The absolute value of the difference between the second operating voltage and the first operating voltage decreases as the doping concentration of the p-type doping material in the p-type charge generation layer decreases.

20. The display device according to claim 19, wherein, The mass percentage content of the p-type doping material in the p-type charge generation layer is greater than or equal to 0.1% and less than or equal to 20%.

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