Display panel and display device

Abstract

Provided in the present application are a display panel and a display device. The absolute value of the highest occupied molecular orbital energy level of a green host material in a green light-emitting unit is increased, and / or, the hole mobility of the green host material in the green light-emitting unit is reduced, so as to reduce the charging amount of a light-emitting stack that emits green light, and increase the charging speed of an anode layer for charging the light-emitting stack that emits green light, thereby alleviating the ghosting problem of a display panel.

Description

Display panel and display device TECHNICAL FIELD

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

[0002] With the development of flat panel display technology, the stability requirement of display for users is gradually improved. In recent years, the organic light emitting diode (OLED) display develops rapidly in the world, and the OLED display technology is increasingly refined. With the improvement of OLED technology and process, the application field of OLED display is gradually expanding to medium and large size. In the field of medium and large size OLED display, the performance requirement of display is higher, especially in terms of service life and power consumption. Under this background, the application demand of long service life and high efficiency of stacked OLED devices is increasing, and major display manufacturers have invested resources in technology and product development, and launched various structures of stacked devices. However, compared with single-layer OLED devices, the stacked OLED device structure still has some problems in performance, such as ghosting problem, which needs to be improved. TECHNICAL PROBLEM

[0003] Embodiments of the present application provide a display panel and a display device to improve the ghosting problem of the display panel. TECHNICAL SOLUTION

[0004] In a first aspect, the present application provides a display panel, comprising a light emitting device layer, wherein the light emitting device layer comprises:

[0005] an anode layer;

[0006] a cathode layer, disposed opposite to the anode layer;

[0007] a light emitting stack, disposed between the anode layer and the cathode layer, and the light emitting stack comprises a green light emitting unit, wherein the highest occupied molecular orbital energy level of a green host material in the green light emitting unit is greater than or equal to -5.8 eV and less than or equal to -5.6 eV, and / or the hole mobility of the green host material in the green light emitting unit is greater than or equal to 10 -6 cm 2 Vs and less than or equal to 10 -5 cm 2 Vs.

[0008] In a second aspect, the present application also provides a display panel, comprising a light emitting device layer, wherein the light emitting device layer comprises:

[0009] an anode layer;

[0010] a cathode layer, disposed opposite to the anode layer;

[0011] a light-emitting stack, disposed between the anode layer and the cathode layer, and the light-emitting stack comprises a green light-emitting unit, an electron blocking unit and a hole transport layer; in one of the light-emitting stacks, the green light-emitting unit is located on a side of the electron blocking unit close to the cathode layer, the hole transport layer is located on a side of the electron blocking unit close to the anode layer, a normal projection of the electron blocking unit on the anode layer overlaps a normal projection of the green light-emitting unit on the anode layer; a highest occupied molecular orbital energy level of an electron blocking material of the electron blocking unit is greater than or equal to -5.7 eV and less than or equal to -5.5 eV, and / or a highest occupied molecular orbital energy level of a hole transport material of the hole transport layer is greater than or equal to -5.7 eV and less than or equal to -5.5 eV.

[0012] In a third aspect, the present application also provides a display panel, comprising a light-emitting device layer, the light-emitting device layer comprising:

[0013] an anode layer;

[0014] a cathode layer, disposed opposite to the anode layer;

[0015] a light-emitting stack, disposed between the anode layer and the cathode layer, and the light-emitting stack comprises a green light-emitting unit, an electron blocking unit and a hole transport layer; in one of the light-emitting stacks, the green light-emitting unit is located on a side of the electron blocking unit close to the cathode layer, the hole transport layer is located on a side of the electron blocking unit close to the anode layer, a normal projection of the electron blocking unit on the anode layer overlaps a normal projection of the green light-emitting unit on the anode layer; a hole mobility of the electron blocking unit is greater than or equal to 10 -5 cm 2 Vs and less than or equal to 10 -4 cm 2 Vs, and / or a hole mobility of the hole transport layer is greater than or equal to 10 -5 cm 2 Vs and less than or equal to 10 -4 cm 2 Vs.

[0016] In a fourth aspect, the present application also provides a display device, comprising the display panel of any of the above embodiments. Advantages

[0017] In the display panel of some embodiments of the present application, the highest occupied molecular orbital energy level of the green light host material of the green light emitting unit is adjusted to be greater than or equal to -5.8 eV and less than or equal to -5.6 eV, and / or the hole mobility of the green light host material of the green light emitting unit is adjusted to be greater than or equal to 10 -6 cm 2 / Vs and less than or equal to 10 -5 cm 2 / Vs, to at least one of reduce the ability of the holes to inject into the green light emitting unit and reduce the number of holes entering into the green light emitting unit, thereby reducing the charging amount of the light emitting stack emitting green light in the light emitting stack, improving the charging speed of the anode layer charging the light emitting stack emitting green light, and improving the ghosting problem of the display panel. At the same time, the problem of the performance deterioration of the green light emitting unit due to the too large highest occupied molecular orbital energy level or the too small hole mobility of the green light host material in the green light emitting unit is improved.

[0018] In the display panel of some embodiments of the present application, the highest occupied molecular orbital energy level of the electron blocking material of the electron blocking unit is adjusted to be greater than or equal to -5.7 eV and less than or equal to -5.5 eV, and / or the highest occupied molecular orbital energy level of the hole transport material of the hole transport layer is adjusted to be greater than or equal to -5.7 eV and less than or equal to -5.5 eV, to effectively reduce the amount of holes injected at the interface between at least one of the electron blocking unit and the hole transport layer and the adjacent film layer, reduce the number of holes injected into the green light emitting unit, thereby reducing the charging amount of the light emitting stack emitting green light in the plurality of light emitting stacks, improving the charging speed of the anode layer charging the light emitting stack emitting green light, and improving the ghosting problem of the display panel. At the same time, the problem of the performance deterioration of the green light emitting unit due to the too large highest occupied molecular orbital energy level of at least one of the electron blocking unit and the hole transport layer is improved.

[0019] In the display panel of some embodiments of the present application, the hole mobility of the electron blocking unit is adjusted to be greater than or equal to 10 -5 cm 2 / Vs and less than or equal to 10 -4 cm 2 / Vs, and / or the hole mobility of the hole transport layer is adjusted to be greater than or equal to 10 -5 cm 2 / Vs and less than or equal to 10 -4 cm 2Vs, to effectively reduce the amount of holes injected at the interface between at least one of the electron blocking unit and the hole transport layer and an adjacent film layer, reduce the number of holes injected into the green light emitting unit, thereby reducing the amount of charge of the light emitting stack emitting green light in the plurality of light emitting stacks, improving the charging speed of the anode layer to charge the light emitting stack emitting green light, and improving the smearing problem of the display panel. At the same time, the problem of poor performance such as large driving voltage of the green light emitting unit caused by too small hole mobility of at least one of the electron blocking unit and the hole transport layer is improved. BRIEF DESCRIPTION OF DRAWINGS

[0020] FIG. 1 is a structural schematic diagram of a display panel according to some embodiments of the present application.

[0021] The following signs are used: 100, display panel; 10, substrate; 1, light emitting device layer; 11, anode layer; 111, first anode; 112, second anode; 113, third anode; 12, cathode layer; 13, charge generation layer; 131, n-type charge generation layer; 132, p-type charge generation layer; 14, light emitting stack; 141, first light emitting stack; 1411, first light emitting layer; 1411A, first green light emitting unit; 1411B, first blue light emitting unit; 1411C, first red light emitting unit; 1412, first electron blocking layer; 1412A, first electron blocking unit; 1412B, second electron blocking unit; 1412C, third electron blocking unit; 1413, first hole transport layer; 1414, hole injection layer; 1415, first hole blocking layer; 216, first electron transport layer; 142, second light emitting stack; 1421, second light emitting layer; 1421A, second green light emitting unit; 1421B, second blue light emitting unit; 1421C, second red light emitting unit; 1422, second electron blocking layer; 1422A, fourth electron blocking unit; 1422B, fifth electron blocking unit; 1422C, sixth electron blocking unit; 1423, second hole transport layer; 1424, second hole blocking layer; 1425, second electron transport layer; 1426, electron injection layer; 31, cover layer; 32, thin film encapsulation layer; 33, driving circuit layer. Embodiments of the present application

[0022] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0023] As shown in FIG. 1, the display panel 100 includes a substrate 10 and a light-emitting device layer 1. The light-emitting device layer 1 is disposed on the substrate 10. The light-emitting device layer 1 includes an anode layer 11, a cathode layer 12, and a light-emitting stack 14.

[0024] The anode layer 11 includes two transparent anode layers and a reflective anode layer between the two transparent anode layers. The material of the transparent anode layer includes a transparent conductive material. The material of the reflective anode layer includes a metal. The anode layer 11 includes a first anode 111, a second anode 112, and a third anode 113 which are spaced apart from each other.

[0025] The cathode layer 12 is disposed in an entirety. The cathode layer 12 is transparent or semi-transparent. The cathode layer 12 includes at least one of a metal material such as magnesium and silver.

[0026] The light-emitting stack 14 is configured to emit light. In some embodiments, as shown in FIG. 1, a plurality of light-emitting stacks 14 are stacked between the anode layer 11 and the cathode layer 12. In other embodiments, one light-emitting stack 14 is disposed between the anode layer 11 and the cathode layer 12.

[0027] In some embodiments, when the plurality of light-emitting stacks 14 are stacked between the anode layer 11 and the cathode layer 12, the light-emitting device layer 1 further includes a charge generation layer 13. The charge generation layer 13 is disposed between adjacent light-emitting stacks 14.

[0028] Exemplarily, the plurality of light-emitting stacks 14 includes a first light-emitting stack 141 and a second light-emitting stack 142. The first light-emitting stack 141 is located between the charge generation layer 13 and the anode layer 11. The second light-emitting stack 142 is located between the charge generation layer 13 and the cathode layer 12. In this way, the light-emitting effect of the display panel 100 is improved while the manufacturing difficulty of the display panel 100 is reduced.

[0029] It can be understood that the number of the light-emitting stacks 14 can also be three or more.

[0030] The charge generation layer 13 includes an n-type charge generation layer 131 and a p-type charge generation layer 132. In the charge generation layer 13, the n-type charge generation layer 131 is located on the side of the p-type charge generation layer 132 close to the anode layer 11.

[0031] Each light-emitting stack 14 includes a light-emitting layer. In some embodiments, the light-emitting layer includes a green light-emitting unit G. The green light-emitting unit G is an organic material layer and can emit green light when a certain voltage is applied between the anode layer 11 and the cathode layer 12. Each green light-emitting unit G includes a green light host material and a green light dopant material. In the green light-emitting unit G, the mass proportion of the green light host material is greater than the mass proportion of the green light dopant material.

[0032] Exemplarily, as shown in FIG. 1, the first light-emitting stack 141 includes a first light-emitting layer 1411, and the first light-emitting layer 1411 includes a first green light-emitting unit 1411A. The second light-emitting stack 142 includes a second light-emitting layer 1421, and the second light-emitting layer 1421 includes a second green light-emitting unit 1421A. In the stacking direction of the plurality of light-emitting stacks 14, the first green light-emitting unit 1411A overlaps the second green light-emitting unit 1421A. The orthographic projection of the first green light-emitting unit 1411A and the second green light-emitting unit 1421A on the substrate 10 overlaps the orthographic projection of the first anode 111 on the substrate 10.

[0033] In some embodiments, the green light host materials in the first green light-emitting unit 1411A and the second green light-emitting unit 1421A are the same. In this way, the first green light-emitting unit 1411A and the second green light-emitting unit 1421A can be prepared using the same material, simplifying the manufacturing process of the display panel 100.

[0034] In other embodiments, the green light host materials in the first green light-emitting unit 1411A and the second green light-emitting unit 1421A can also be different. In this way, different functional requirements of the first green light-emitting unit 1411A and the second green light-emitting unit 1421A can be met.

[0035] In some embodiments, the highest occupied molecular orbital (HOMO) energy level of the green light host material in the at least one green light-emitting unit G is greater than or equal to -5.8 eV and less than or equal to -5.6 eV. In this way, the highest occupied molecular orbital energy level of the green light host material in the at least one green light-emitting unit G is deepened to effectively reduce the ability of hole injection into the green light-emitting unit G, thereby reducing the charging amount of the light-emitting stack 14 that emits green light, improving the charging speed of the anode layer 11 to charge the light-emitting stack that emits green light, and improving the ghosting problem of the display panel 100. At the same time, the problem of performance deterioration caused by the highest occupied molecular orbital energy level of the green light host material in the green light-emitting unit being too large, resulting in a larger driving voltage of the green light-emitting unit, is improved.

[0036] Optionally, the highest occupied molecular orbital energy level of the green light host material in the at least one green light-emitting unit G is greater than or equal to -5.75 eV and less than or equal to -5.65 eV. Optionally, the highest occupied molecular orbital energy level of the green light host material in the at least one green light-emitting unit is greater than or equal to -5.8 eV and less than or equal to -5.7 eV.

[0037] Exemplarily, the highest occupied molecular orbital energy level of the green light host material in the at least one green light emitting unit G comprises a combination of one or more of the following highest occupied molecular orbital energy levels: -5.61 eV, -5.62 eV, -5.63 eV, -5.64 eV, -5.65 eV, -5.66 eV, -5.67 eV, -5.68 eV, -5.69 eV, -5.70 eV, -5.71 eV, -5.72 eV, -5.73 eV, -5.74 eV, -5.75 eV, -5.76 eV, -5.77 eV, -5.78 eV, -5.79 eV, and -5.80 eV.

[0038] In some embodiments, the highest occupied molecular orbital energy level of the green light host material in the green light emitting unit G of each of the plurality of light emitting stacks 14 is greater than or equal to -5.8 eV and less than or equal to -5.6 eV. In this way, the highest occupied molecular orbital energy level of the green light host material of the green light emitting unit G of each of the plurality of light emitting stacks 14 is adjusted, the charge amount of the light emitting stack emitting green light in the plurality of light emitting stacks 14 is maximally reduced, the charging speed of the anode layer 11 charging the light emitting stack emitting green light is maximally improved, and the ghosting problem of the display panel 100 is better improved. At the same time, the problem of the performance of the green light emitting unit being deteriorated due to the highest occupied molecular orbital energy level of the green light host material in the green light emitting unit being too large, etc. is improved. In addition, the same material is used for the plurality of green light emitting units, and the manufacturing process of the display panel 100 is simplified.

[0039] Exemplarily, the highest occupied molecular orbital energy level of the green light host material in the first green light emitting unit 1411A and the second green light emitting unit 1421A is greater than or equal to -5.8 eV and less than or equal to -5.6 eV.

[0040] It can be understood that in other embodiments, the highest occupied molecular orbital energy level of the green light host material in one of the first green light emitting unit 1411A and the second green light emitting unit 1421A can also be greater than or equal to -5.8 eV and less than or equal to -5.6 eV.

[0041] In some embodiments, the hole mobility of the green light host material in the at least one green light emitting unit G is greater than or equal to 10 -6 cm 2 / Vs and less than or equal to 10 -5 cm 2 / Vs. In this way, the hole mobility of the green light host material of the green light emitting unit G is adjusted to be greater than or equal to 10 -6 cm 2 / Vs and less than or equal to 10 -5 cm 2Vs, to reduce the number of holes entering into the green light emitting unit G, thereby reducing the charging amount of the light emitting stack emitting green light in the light emitting stack 14, improving the charging speed of the anode layer 11 charging the light emitting stack emitting green light, and improving the ghosting problem of the display panel 100. Meanwhile, the problem of the hole mobility of the green light host material in the green light emitting unit being too small to cause the driving voltage of the green light emitting unit to become large and other performance deterioration problems are improved.

[0042] Optionally, the hole mobility of the green light host material in the at least one green light emitting unit G is greater than or equal to 2*10 -6 cm 2 Vs and less than or equal to 0.8*10 -5 cm 2 Vs. Optionally, the hole mobility of the green light host material in the at least one green light emitting unit is greater than or equal to 4*10 -6 cm 2 Vs and less than or equal to 0.7*10 -5 cm 2 Vs.

[0043] Exemplarily, the hole mobility of the green light host material in the at least one green light emitting unit G includes a combination of one or more of the following hole mobilities: 10 -6 cm 2 Vs, 2*10 -6 cm 2 Vs, 3*10 -6 cm 2 Vs, 4*10 -6 cm 2 Vs, 5*10 -6 cm 2 Vs, 6*10 -6 cm 2 Vs, 7*10 -6 cm 2 Vs, 8*10 -6 cm 2 Vs, 9*10 -6 cm 2 Vs, and 10 -5 cm 2 Vs.

[0044] In some embodiments, the hole mobility of the green light host material in the green light emitting unit G of each of the plurality of light emitting stacks 14 is greater than or equal to 10 -6 cm 2 Vs and less than or equal to 10 -5 cm 2Vs. In this way, the number of holes entering the green light emitting unit G is reduced, thereby reducing the charging amount of the green light emitting unit in the plurality of light emitting stacks 14, improving the charging speed of the anode layer 11 to the green light emitting unit, and improving the ghosting problem of the display panel 100. At the same time, the problem of the hole mobility of the green light host material in the green light emitting unit being too small, resulting in a large driving voltage of the green light emitting unit and other performance degradation, is improved. In addition, the same material is used in the plurality of green light emitting units, simplifying the manufacturing process of the display panel 100.

[0045] Exemplarily, the hole mobility of the green light host material in the first green light emitting unit 1411A and the second green light emitting unit 1421A is greater than or equal to 10 -6 cm 2 / Vs and less than or equal to 10 -5 cm 2 / Vs.

[0046] It can be understood that in other embodiments, the hole mobility of the green light host material in one of the first green light emitting unit 1411A and the second green light emitting unit 1421A can be greater than or equal to 10 -6 cm 2 / Vs and less than or equal to 10 -5 cm 2 / Vs.

[0047] In some embodiments, the green light host material in at least one green light emitting unit G can include at least one of a p-type green light host material and an n-type green light host material, but is not limited thereto. The p-type green light host material includes, but is not limited to, at least one of a carbazole compound and an indolocarbazole compound. The n-type green light host material includes, but is not limited to, at least one of a triazine compound, a diphenylfuran compound, and a triphenylene compound. In this way, by optimizing the green light host material in the green light emitting unit G, the highest occupied molecular orbital energy level of the green light host material in at least one green light emitting unit is adjusted to be greater than or equal to -5.8 eV and less than or equal to -5.6 eV, or the hole mobility of the green light host material in at least one green light emitting unit is adjusted to be greater than or equal to 10 -6 cm 2 / Vs and less than or equal to 10 -5 cm 2 / Vs.

[0048] In some embodiments, each light emitting layer further includes a blue light emitting unit and a red light emitting unit. The blue light emitting unit has a projection on the substrate 10 that overlaps with a projection of the second anode 112 on the substrate 10. The red light emitting unit has a projection on the substrate 10 that overlaps with a projection of the third anode 113 on the substrate 10.

[0049] Exemplarily, the first light-emitting layer 1411 further comprises a first blue light-emitting unit 1411B and a first red light-emitting unit 1411C. The second light-emitting layer 1421 further comprises a second blue light-emitting unit 1421B and a second red light-emitting unit 1421C. In the stacking direction of the plurality of light-emitting stacks 14, the first blue light-emitting unit 1411B overlaps the second blue light-emitting unit 1421B, and the first red light-emitting unit 1411C overlaps the second red light-emitting unit 1421C.

[0050] In some embodiments, the light-emitting stack 14 further comprises an electron blocking unit FLG. In one light-emitting stack 14, the green light-emitting unit G is located at the side of the electron blocking unit FLG close to the cathode layer 12. The orthogonal projection of the electron blocking unit FLG on the anode layer 11 overlaps the orthogonal projection of the green light-emitting unit G on the anode layer 11.

[0051] Exemplarily, the first light-emitting stack 141 comprises a first electron blocking layer 1412 located at the side of the first light-emitting layer 1411 close to the anode layer 11. The first electron blocking layer 1412 comprises a first electron blocking unit 1412A which is superposed with and in contact with the first green light-emitting unit 1411A. The second light-emitting stack 142 comprises a second electron blocking layer 1422 located at the side of the second light-emitting layer 1421 close to the anode layer 11. The second electron blocking layer 1422 comprises a fourth electron blocking unit 1422A which is superposed with and in contact with the second green light-emitting unit 1421A. In the stacking direction of the plurality of light-emitting stacks 14, the first electron blocking unit 1412A overlaps the fourth electron blocking unit 1422A. The orthogonal projection of the first electron blocking unit 1412A and the fourth electron blocking unit 1422A on the substrate 10 overlaps the orthogonal projection of the first green light-emitting unit 1411A and the second green light-emitting unit 1421A on the substrate 10.

[0052] In some embodiments, the highest occupied molecular orbital energy level of the electron blocking material of the at least one electron blocking unit FLG is greater than or equal to -5.7 eV and less than or equal to -5.5 eV. In this way, the highest occupied molecular orbital energy level of the electron blocking material of the electron blocking unit FLG disposed in overlap with the green light emitting unit G is adjusted to be greater than or equal to -5.7 eV and less than or equal to -5.5 eV to effectively reduce the amount of hole injection at the interface of the electron blocking unit FLG and the adjacent film layer (e.g., the green light emitting unit), adjust the amount of hole injection to the green light emitting unit G, thereby reducing the amount of charge of the light emitting stack emitting green light in the plurality of light emitting stacks 14, improving the charging speed of the anode layer 11 charging the light emitting stack emitting green light, and improving the ghosting problem of the display panel 100. At the same time, the problem of performance deterioration caused by the highest occupied molecular orbital energy level of the electron blocking material of the electron blocking unit FLG disposed in overlap with the green light emitting unit G being too large to cause the driving voltage of the green light emitting unit G to become large, etc. is improved.

[0053] Optionally, the highest occupied molecular orbital energy level of the electron blocking material of the at least one electron blocking unit FLG is greater than or equal to -5.7 eV and less than or equal to -5.6 eV. Optionally, the highest occupied molecular orbital energy level of the electron blocking material of the at least one electron blocking unit FLG is greater than or equal to -5.65 eV and less than or equal to -5.55 eV.

[0054] Illustratively, the highest occupied molecular orbital energy level of the electron blocking material of the at least one electron blocking unit FLG includes a combination of one or more of the following highest occupied molecular orbital energy levels: -5.51 eV, -5.52 eV, -5.53 eV, -5.54 eV, -5.55 eV, -5.56 eV, -5.57 eV, -5.58 eV, -5.59 eV, -5.60 eV, -5.61 eV, -5.62 eV, -5.63 eV, -5.64 eV, -5.65 eV, -5.66 eV, -5.67 eV, -5.68 eV, -5.69 eV, and -5.70 eV.

[0055] In some embodiments, the highest occupied molecular orbital energy level of the electron blocking material of the electron blocking unit FLG overlapping each green light emitting unit G in the plurality of light emitting stacks 14 is greater than or equal to -5.7 eV and less than or equal to -5.5 eV. In this way, the problem of performance deterioration caused by the highest occupied molecular orbital energy level of the electron blocking material of the electron blocking unit FLG disposed in overlap with the green light emitting unit G being too large to cause the driving voltage of the green light emitting unit to become large, etc. is improved while improving the ghosting problem of the display panel 100. Furthermore, the materials of the plurality of electron blocking units overlapping the plurality of green light emitting units can be the same, simplifying the manufacturing process of the display panel 100.

[0056] Exemplarily, the highest occupied molecular orbital energy level of the electron blocking material of the first electron blocking unit 1412A and the fourth electron blocking unit 1422A is greater than or equal to -5.7 eV and less than or equal to -5.5 eV.

[0057] It can be understood that, in other embodiments, the highest occupied molecular orbital energy level of the electron blocking material of one of the first electron blocking unit 1412A and the fourth electron blocking unit 1422A is greater than or equal to -5.7 eV and less than or equal to -5.5 eV.

[0058] In some embodiments, the light emitting stack 14 further comprises an electron blocking unit FLG, the green light emitting unit G is located at a side of the electron blocking unit FLG close to the cathode layer 12 in one light emitting stack 14, the orthographic projection of the electron blocking unit FLG on the anode layer 11 overlaps with the orthographic projection of the green light emitting unit G on the anode layer 11, and the hole mobility of at least one electron blocking unit FLG is greater than or equal to 10 -5 cm 2 Vs and less than or equal to 10 -4 cm 2 Vs. In this way, the hole mobility of the electron blocking unit FLG overlapping with the green light emitting unit G is adjusted to be greater than or equal to 10 -5 cm 2 Vs and less than or equal to 10 -4 cm 2 Vs, so as to effectively reduce the amount of hole injection at the interface between the electron blocking unit FLG and the adjacent film layer, reduce the number of holes injected into the green light emitting unit G, thereby reducing the charging amount of the light emitting stack emitting green light in the plurality of light emitting stacks 14, improving the charging speed of the anode layer 11 charging the light emitting stack emitting green light, and improving the ghosting problem of the display panel 100. At the same time, the problem of performance deterioration caused by the hole mobility of the electron blocking unit being too small and the driving voltage of the green light emitting unit being too large is improved.

[0059] Optionally, the hole mobility of at least one electron blocking unit FLG is greater than or equal to 2*10 -5 cm 2 Vs and less than or equal to 0.8*10 -4 cm 2 Vs. Optionally, the hole mobility of at least one electron blocking unit is greater than or equal to 4*10 -5 cm 2 Vs and less than or equal to 0.7*10 -4 cm 2 Vs.

[0060] Exemplarily, the hole mobility of the at least one electron blocking unit FLG comprises a combination of one or more of the following hole mobilities: 10 -5 cm 2 Vs, 2*10 -5 cm 2 Vs, 3*10 -5 cm 2 Vs, 4*10 -5 cm 2 Vs, 5*10 -5 cm 2 Vs, 6*10 -5 cm 2 Vs, 7*10 -5 cm 2 Vs, 8*10 -5 cm 2 Vs, 9*10 -5 cm 2 Vs, and 10 -4 cm 2 Vs.

[0061] In some embodiments, the hole mobility of each electron blocking unit FLG in the plurality of light emitting stacks 14 overlapping with the green light emitting unit G is greater than or equal to 10 -5 cm 2 Vs and less than or equal to 10 -4 cm 2 Vs. In this way, the hole mobility of the electron blocking unit FLG overlapping with the green light emitting unit G is adjusted to be greater than or equal to 10 -5 cm 2 Vs and less than or equal to 10 -4 cm 2 Vs, effectively reducing the amount of hole injection at the interface of the electron blocking unit and the adjacent film layer (green light emitting unit), reducing the number of holes injected into the green light emitting unit G, thereby reducing the charging amount of the light emitting stack emitting green light in the plurality of light emitting stacks 14, improving the charging speed of the anode layer 11 charging the light emitting stack emitting green light, and improving the smearing problem of the display panel 100. At the same time, the problem of performance deterioration caused by the hole mobility of the electron blocking unit FLG being too small and the driving voltage of the green light emitting unit becoming larger is improved. In addition, the plurality of electron blocking units FLG of the green light emitting unit use the same material, simplifying the manufacturing process of the display panel 100.

[0062] Exemplarily, the hole mobility of the first electron blocking unit 1412A and the fourth electron blocking unit 1422A is greater than or equal to 10 -5 cm 2 Vs and less than or equal to 10 -4cm 2 / Vs.

[0063] It can be understood that, in other embodiments, the hole mobility of one of the first electron blocking unit 1412A and the fourth electron blocking unit 1422A can be greater than or equal to 10 -5 cm 2 / Vs and less than or equal to 10 -4 cm 2 / Vs.

[0064] In some embodiments, the material of the at least one electron blocking unit FLG (the first electron blocking unit 1412A and the fourth electron blocking unit 1422A) can be selected from at least one of a diphenylamine compound, a carbazole compound, and a triphenylamine compound. In this way, by the preference of the material of the electron blocking unit, the highest occupied molecular orbital energy level of the electron blocking material of the at least one electron blocking unit is adjusted to be greater than or equal to -5.7 eV and less than or equal to -5.5 eV, or the hole mobility of the at least one electron blocking unit is adjusted to be greater than or equal to 10 -5 cm 2 / Vs and less than or equal to 10 -4 cm 2 / Vs.

[0065] In some embodiments, as shown in FIG. 1, the first electron blocking layer 1412 can further include a second electron blocking unit 1412B, and the second electron blocking layer 1422 can further include a fifth electron blocking unit 1422B. The orthographic projection of the second electron blocking unit 1412B and the fifth electron blocking unit 1422B on the substrate 10 overlaps with the orthographic projection of the second blue light emitting unit 1421B and the first blue light emitting unit 1411B on the substrate 10. The thickness of the second electron blocking unit 1412B and the fifth electron blocking unit 1422B can be less than the thickness of the first electron blocking unit 1412A and the fourth electron blocking unit 1422A, but is not limited thereto.

[0066] In some embodiments, as shown in FIG. 1, the first electron blocking layer 1412 can further include a third electron blocking unit 1412C, and the second electron blocking layer 1422 can further include a sixth electron blocking unit 1422C. The orthographic projection of the third electron blocking unit 1412C and the sixth electron blocking unit 1422C on the substrate 10 overlaps with the orthographic projection of the second red light emitting unit 1421C and the first red light emitting unit 1411C on the substrate 10. The thickness of the third electron blocking unit 1412C and the sixth electron blocking unit 1422C can be greater than the thickness of the first electron blocking unit 1412A and the fourth electron blocking unit 1422A, but is not limited thereto.

[0067] In some embodiments, as shown in FIG. 1, the light-emitting stack 14 further comprises a hole transport layer HTL, and the green light-emitting unit G is located on the side of the hole transport layer HTL close to the cathode layer 12 in one light-emitting stack 14.

[0068] Exemplarily, the first light-emitting stack 141 comprises a first light-emitting layer 1411, a first electron blocking layer 1412, and a first hole transport layer 1413 located on the side of the first light-emitting layer 1411 close to the anode layer 11. The first electron blocking layer 1412 is located between the first hole transport layer 1413 and the first light-emitting layer 1411. The first hole transport layer 1413 is in contact with the first electron blocking layer 1412. The second light-emitting stack 142 comprises a second light-emitting layer 1421, a second electron blocking layer 1422, and a second hole transport layer 1423 located on the side of the second light-emitting layer 1421 close to the anode layer 11. The second electron blocking layer 1422 is located between the second hole transport layer 1423 and the second light-emitting layer 1421. The second hole transport layer 1423 is in contact with the second electron blocking layer 1422.

[0069] In some embodiments, the highest occupied molecular orbital energy level of the hole transport material of the at least one hole transport layer HTL is greater than or equal to -5.7 eV and less than or equal to -5.5 eV. In this way, the highest occupied molecular orbital energy level of the hole transport material of the at least one hole transport layer HTL is adjusted to be greater than or equal to -5.7 eV and less than or equal to -5.5 eV, so as to effectively reduce the amount of hole injection at the interface between the hole transport layer and the adjacent film layer (electron blocking layer), reduce the number of holes injected into the green light-emitting unit G, thereby reducing the charging amount of the light-emitting stack emitting green light in the plurality of light-emitting stacks 14, improving the charging speed of the anode layer 11 to charge the light-emitting stack emitting green light, and improving the ghosting problem of the display panel 100. At the same time, the problem of performance deterioration caused by the too large highest occupied molecular orbital energy level of the hole transport material of the hole transport layer, which leads to the increase of the driving voltage of the green light-emitting unit, is improved.

[0070] Optionally, the highest occupied molecular orbital energy level of the hole transport material of the at least one hole transport layer HTL is greater than or equal to -5.7 eV and less than or equal to -5.6 eV. Optionally, the highest occupied molecular orbital energy level of the hole transport material of the at least one hole transport layer is greater than or equal to -5.65 eV and less than or equal to -5.55 eV.

[0071] Exemplarily, the highest occupied molecular orbital energy level of the hole transport material of the at least one hole transport layer HTL comprises a combination of one or more of the following highest occupied molecular orbital energy levels: -5.51 eV, -5.52 eV, -5.53 eV, -5.54 eV, -5.55 eV, -5.56 eV, -5.57 eV, -5.58 eV, -5.59 eV, -5.60 eV, -5.61 eV, -5.62 eV, -5.63 eV, -5.64 eV, -5.65 eV, -5.66 eV, -5.67 eV, -5.68 eV, -5.69 eV, and -5.70 eV.

[0072] In some embodiments, the highest occupied molecular orbital energy level of the hole transport material of the hole transport layer HTL in each light-emitting stack 14 is greater than or equal to -5.7 eV and less than or equal to -5.5 eV. In this way, the problem of ghosting of the display panel 100 is improved, while the problem of the performance of the green light-emitting unit deteriorating due to the driving voltage becoming large because the highest occupied molecular orbital energy level of the hole transport layer is too large is also improved. Furthermore, the materials of the plurality of hole transport layers can be the same, simplifying the manufacturing process of the display panel 100.

[0073] Exemplarily, the highest occupied molecular orbital energy level of the hole transport material of the first hole transport layer 1413 and the second hole transport layer 1423 is greater than or equal to -5.7 eV and less than or equal to -5.5 eV.

[0074] It can be understood that in other embodiments, the highest occupied molecular orbital energy level of the hole transport material of one of the first hole transport layer 1413 and the second hole transport layer 1423 can also be greater than or equal to -5.7 eV and less than or equal to -5.5 eV.

[0075] In some embodiments, the hole mobility of the at least one hole transport layer HTL is greater than or equal to 10 -5 cm 2 / Vs and less than or equal to 10 -4 cm 2 / Vs. In this way, the hole mobility of the at least one hole transport layer HTL is adjusted to be greater than or equal to 10 -5 cm 2 / Vs and less than or equal to 10 -4 cm 2Vs, to effectively reduce the amount of holes injected at the interface of the hole transport layer and the adjacent film layer, thereby reducing the charging amount of the light emitting stack emitting green light in the plurality of light emitting stacks 14, improving the charging speed of the anode layer 11 charging the light emitting stack emitting green light, and improving the problem of ghosting of the display panel 100. At the same time, the problem of performance deterioration such as the driving voltage of the green light emitting unit becoming large due to the small hole mobility of the hole transport layer is improved.

[0076] Optionally, the hole mobility of the at least one hole transport layer HTL is greater than or equal to 2*10 -5 cm 2 Vs and less than or equal to 0.8*10 -4 cm 2 Vs. Optionally, the hole mobility of the at least one hole transport layer HTL is greater than or equal to 4*10 -5 cm 2 Vs and less than or equal to 0.7*10 -4 cm 2 Vs.

[0077] Exemplarily, the hole mobility of the at least one hole transport layer HTL includes a combination of one or more of the following hole mobilities: 10 -5 cm 2 Vs, 2*10 -5 cm 2 Vs, 3*10 -5 cm 2 Vs, 4*10 -5 cm 2 Vs, 5*10 -5 cm 2 Vs, 6*10 -5 cm 2 Vs, 7*10 -5 cm 2 Vs, 8*10 -5 cm 2 Vs, 9*10 -5 cm 2 Vs, and 10 -4 cm 2 Vs.

[0078] In some embodiments, the hole mobility of each hole transport layer HTL in the plurality of light emitting stacks 14 is greater than or equal to 10 -5 cm 2 Vs and less than or equal to 10 -4 cm 2 Vs. In this way, the hole mobility of the hole transport layer is adjusted to be greater than or equal to 10 -5cm 2 Vs and less than or equal to 10 -4 cm 2 Vs, to effectively reduce the amount of holes injected at the interface of the hole transport layer and the adjacent film layer (the electron blocking unit), reduce the number of holes injected into the green light emitting unit G, thereby reducing the amount of charge of the light emitting stack emitting green light in the plurality of light emitting stacks 14, improving the charging speed of the anode layer 11 to charge the light emitting stack emitting green light, and improving the ghosting problem of the display panel 100. At the same time, the problem of performance deterioration caused by the hole transport layer having a too small hole mobility and the green light emitting unit having a large driving voltage is improved. In addition, the plurality of hole transport layers use the same material, simplifying the manufacturing process of the display panel 100.

[0079] Exemplarily, the hole mobility of the first hole transport layer 1413 and the second hole transport layer 1423 is greater than or equal to 10 -5 cm 2 Vs and less than or equal to 10 -4 cm 2 Vs.

[0080] In some embodiments, the hole transport material of the at least one hole transport layer HTL can be selected from at least one of diphenylamine compounds, carbazole compounds, and triphenylamine compounds. In this way, by optimizing the hole transport material, the hole mobility of the at least one hole transport layer is adjusted to be greater than or equal to 10 -5 cm 2 Vs and less than or equal to 10 -4 cm 2 Vs, or the highest occupied molecular orbital energy level of the hole transport material of the at least one hole transport layer is adjusted to be greater than or equal to -5.7 eV and less than or equal to -5.5 eV.

[0081] In some embodiments, the highest occupied molecular orbital energy level of the hole transport material of the at least one hole transport layer HTL is 0.05 eV to 0.2 eV smaller than the highest occupied molecular orbital energy level of the electron blocking material of the at least one electron blocking unit (at least one of the first electron blocking unit 1412A and the second electron blocking unit 1412B).

[0082] It can be understood that in other embodiments, the hole mobility of one of the first hole transport layer 1413 and the second hole transport layer 1423 can also be greater than or equal to 10 -5 cm 2 Vs and less than or equal to 10 -4 cm 2 Vs.

[0083] It should be noted that compared with other common film layers in each light-emitting stack 14, adjusting the highest occupied molecular orbital energy level of the hole transport material of the hole transport layer HTL, or reducing the hole mobility of the hole transport layer, has less effect on the light-emitting stack 14.

[0084] In some embodiments, as shown in FIG. 1, the first light-emitting stack 141 further includes a hole injection layer 1414, which is located between the first hole transport layer 1413 and the anode layer 11.

[0085] In some embodiments, as shown in FIG. 1, the first light-emitting stack 141 further includes a first hole blocking layer 1415, which is located between the first light-emitting layer 1411 and the charge generation layer 13.

[0086] In some embodiments, as shown in FIG. 1, the first light-emitting stack 141 further includes a first electron transport layer 1416, which is located between the first light-emitting layer 1411 and the charge generation layer 13. In the case where the first light-emitting stack 141 includes the first hole blocking layer 1415, the first electron transport layer 1416 is located between the first hole blocking layer 1415 and the charge generation layer 13.

[0087] In some embodiments, as shown in FIG. 1, the second light-emitting stack 142 further includes a second hole blocking layer 1424, which is located between the second light-emitting layer 1421 and the cathode layer 12.

[0088] In some embodiments, as shown in FIG. 1, the second light-emitting stack 142 further includes a second electron transport layer 1425, which is located between the second light-emitting layer 1421 and the cathode layer 12. In the case where the second light-emitting stack 142 includes the second hole blocking layer 1424, the second electron transport layer 1425 is located between the second hole blocking layer 1424 and the electron injection layer 1426.

[0089] In some embodiments, as shown in FIG. 1, the second light-emitting stack 142 further includes an electron injection layer 1426, which is located between the cathode layer 12 and the second light-emitting layer 1421. In the case where the second light-emitting stack 142 includes the second electron transport layer 1425, the electron injection layer 1426 is located between the second electron transport layer 1425 and the cathode layer 12.

[0090] In some embodiments, as shown in FIG. 1, the display panel 100 further includes a pixel driving circuit layer 33, which is disposed between the substrate 10 and the light-emitting device layer 1. The pixel driving circuit layer 33 includes a plurality of pixel driving circuits, which are respectively connected with a plurality of anodes of the anode layer 11.

[0091] In some embodiments, as shown in FIG. 1, the display panel 100 further comprises a cover layer 31 located on the side of the cathode layer 12 away from the anode layer 11. The refractive index of the cover layer 31 is greater than the refractive index of the cathode layer 12 to improve the light extraction efficiency of the light-emitting device layer 1. The cover layer 31 can comprise an organic material.

[0092] In some embodiments, as shown in FIG. 1, the display panel 100 further comprises a thin film encapsulation layer 32 located on the side of the cover layer 31 away from the cathode layer 12. The thin film encapsulation layer 32 can comprise two inorganic encapsulation layers and an organic encapsulation layer located between the two inorganic encapsulation layers.

[0093] Based on the same inventive concept, the present application also provides a display device comprising the display panel 100 of any of the above embodiments.

[0094] In summary, in the display panel and display of some embodiments of the present application, the charge amount of the light-emitting stack emitting green light in the plurality of light-emitting stacks is reduced by adjusting the hole-related properties of the light-emitting stack. Specifically, the highest occupied molecular orbital level of at least one of the green light host material in the green light-emitting unit, the electron blocking material of the electron blocking unit overlapping the green light-emitting unit, and the hole transport material of the hole transport layer is adjusted, and / or the hole mobility of at least one of the green light host material in the green light-emitting unit, the electron blocking unit overlapping the green light-emitting unit, and the hole transport layer is adjusted, the holes injected into the green light-emitting unit are adjusted to reduce the charge amount of the light-emitting stack emitting green light in the plurality of light-emitting stacks, improve the charging speed of the anode layer charging the light-emitting stack emitting green light, and improve the ghosting problem of the display panel.

[0095] It should be noted that the applicant has found through a large number of creative experimental explorations that adjusting the hole-related properties of the light-emitting stack can more obviously adjust the charge amount of the light-emitting stack emitting green light than adjusting the electron-related properties of the light-emitting stack.

[0096] The green light-emitting device of the following examples and comparative examples is used to verify the technical solutions of the present application.

[0097] The green light emitting device comprises a cathode layer, an anode layer and a green light emitting stack, and the green light emitting stack is located between the cathode layer and the anode layer. The anode layer comprises a first ITO layer (40 nm in thickness), an Ag layer (140 nm in thickness) and a second ITO layer (20 nm in thickness) which are sequentially stacked. The cathode layer is a magnesium-silver alloy layer (15 nm in thickness). The green light emitting stack comprises a hole injection layer (10 nm in thickness, and the material is 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HATCN)), a hole transport layer (20 nm in thickness, and the material is 1-bis[4-[N,N-N-di(4-methylphenyl)amino]phenyl]-cyclohexane (TAPC)), an electron blocking layer (15 nm in thickness, and the material is 4,4,4-tris(N-carbazolyl)-triphenylamine (TCTA)), a green light emitting unit (40 nm in thickness, and the green light emitting unit comprises a green light host material and a green light dopant material, the green light host material is a carbazole compound, and the green light dopant material is an iridium complex, and the mass content of the green light host material in the green light emitting unit is 5%), a hole blocking layer (4 nm in thickness, and the material is 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi)), an electron transport layer (10-40 nm in thickness, and the material is 1,3,5-tris(3-pyridyl-3-phenyl)benzene (TmPyPB)), an N-type charge generation layer (10 nm in thickness, and the material is ytterbium-doped 4,7-diphenyl-1,10-phenanthroline (Bphen:Yb), and the mass percentage of ytterbium in the electron transport layer is 3%), a P-type charge generation layer (10 nm in thickness, and the material is 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HATCN)), and an electron injection layer (1-2 nm in thickness, and the material is ytterbium).

[0098] In addition, the green light emitting devices of Example 1 to Example 3 and Comparative Example 1 are basically similar, and the difference is that the highest occupied molecular orbital energy levels of the green light host materials of the four are different. The green light host materials of the four all belong to carbazole compounds, and the modification groups of the carbazole compounds of the four are different.

[0099] In addition, the green light emitting devices of Example 4 to Example 6 and Comparative Example 2 are basically similar, and the difference is that the hole mobilities of the green light host materials of the four are different. The green light host materials of the four all belong to carbazole compounds, and the modification groups of the carbazole compounds of the four are different.

[0100] Charging power of the green light emitting devices of Example 1 to Example 3 and Comparative Example 1 in Table 1

[0101] From Table 1, it can be seen that the charging power of the green light emitting devices of Examples 1 to 3 is less than that of the green light emitting device of Comparative Example 1. Therefore, the highest occupied molecular orbital energy level of the green light host material is -5.8 eV to -5.6 eV, which can reduce the charging power of the green light emitting device.

[0102] Charging power of green light emitting devices of Examples 4 to 6 and Comparative Example 2

[0103] From Table 2, it can be seen that the charging power of the green light emitting devices of Examples 4 to 6 is less than that of the green light emitting device of Comparative Example 2. Therefore, the hole mobility of the green light host material is 10 -6 cm 2 Vs to 10 -5 cm 2 Vs, which can reduce the charging power of the green light emitting device.

[0104] The above descriptions of the embodiments are only used to help understand the technical solutions and the core ideas of the present application; it should be understood by those skilled in the art that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A display panel, wherein, comprises a light-emitting device layer, the light-emitting device layer comprising: an anode layer; a cathode layer disposed opposite to the anode layer; A light-emitting stack is disposed between the anode layer and the cathode layer, and the light-emitting stack includes a green light-emitting unit, a highest occupied molecular orbital energy level of a green host material in the green light-emitting unit is greater than or equal to -5.8 eV and less than or equal to -5.6 eV, and / or a hole mobility of the green host material in the green light-emitting unit is greater than or equal to 10 -6 cm 2 / Vs and less than or equal to 10 -5 cm 2 / Vs.

2. The display panel of claim 1, wherein, a highest occupied molecular orbital energy level of a green light host material in the green light emitting unit is greater than or equal to -5.75 eV and less than or equal to -5.65 eV.

3. The display panel of claim 1, wherein, the light-emitting stack further comprises an electron blocking unit, in one of the light-emitting stacks the green light emitting unit is located at a side of the electron blocking unit close to the cathode layer, a footprint of the electron blocking unit on the anode layer overlaps with a footprint of the green light emitting unit on the anode layer, a highest occupied molecular orbital energy level of an electron blocking material of the electron blocking unit is greater than or equal to -5.7 eV and less than or equal to -5.5 eV.

4. The display panel of claim 3, wherein, a highest occupied molecular orbital energy level of an electron blocking material of the electron blocking unit is greater than or equal to -5.7 eV and less than or equal to -5.6 eV.

5. The display panel of claim 1, wherein, The light emitting stack further comprises an electron blocking unit, in one of the light emitting stacks the green light emitting unit is located on a side of the electron blocking unit closer to the cathode layer, a positive projection of the electron blocking unit on the anode layer overlaps a positive projection of the green light emitting unit on the anode layer, the hole mobility of the electron blocking unit is greater than or equal to 10 -5 cm 2 / Vs and less than or equal to 10 -4 cm 2 / Vs.

6. The display panel of claim 1, wherein, the light-emitting stack further comprises a hole transport layer, in one of the light-emitting stacks the green light emitting unit is located at a side of the hole transport layer close to the cathode layer, a highest occupied molecular orbital energy level of a hole transport material of the hole transport layer is greater than or equal to -5.7 eV and less than or equal to -5.5 eV.

7. The display panel of claim 6, wherein, a highest occupied molecular orbital energy level of a hole transport material of the hole transport layer is greater than or equal to -5.7 eV and less than or equal to -5.6 eV.

8. The display panel of claim 1, wherein, The light emitting stack further comprises a hole transporting layer, in one of the light emitting stacks the green light emitting unit is located on the side of the hole transporting layer closer to the cathode layer, the hole transporting layer has a hole mobility greater than or equal to 10 -5 cm 2 Vs and less than or equal to 10 -4 cm 2 Vs.

9. The display panel of claim 1, wherein, a number of the light-emitting stacks is a plurality, the display panel further comprises a charge generation layer, the charge generation layer is located between two adjacent light-emitting stacks, each of the light-emitting stacks comprises the green light emitting unit, a blue light emitting unit and a red light emitting unit.

10. The display panel of claim 1, the green light host material comprises at least one of a p-type green light host material and an n-type green light host material, the p-type green light host material is selected from at least one of a carbazole compound and an indolocarbazole compound, the n-type green light host material is selected from at least one of a triazine compound, a diphenylfuran compound and a triphenylene compound.

11. A display device, wherein, comprises a display panel, the display panel comprises a light-emitting device layer, the light-emitting device layer comprising: an anode layer; a cathode layer disposed opposite to the anode layer; A light-emitting stack is disposed between the anode layer and the cathode layer, and the light-emitting stack includes a green light-emitting unit, a highest occupied molecular orbital energy level of a green host material in the green light-emitting unit is greater than or equal to -5.8 eV and less than or equal to -5.6 eV, and / or a hole mobility of the green host material in the green light-emitting unit is greater than or equal to 10 -6 cm 2 / Vs and less than or equal to 10 -5 cm 2 / Vs.

12. The display device of claim 11, wherein, a highest occupied molecular orbital energy level of a green light host material in the green light emitting unit is greater than or equal to -5.75 eV and less than or equal to -5.65 eV.

13. The display device of claim 11, wherein, the light-emitting stack further comprises an electron blocking unit, in one of the light-emitting stacks the green light emitting unit is located at a side of the electron blocking unit close to the cathode layer, a footprint of the electron blocking unit on the anode layer overlaps with a footprint of the green light emitting unit on the anode layer, a highest occupied molecular orbital energy level of an electron blocking material of the electron blocking unit is greater than or equal to -5.7 eV and less than or equal to -5.5 eV.

14. The display device of claim 13, wherein, a highest occupied molecular orbital energy level of an electron blocking material of the electron blocking unit is greater than or equal to -5.7 eV and less than or equal to -5.6 eV.

15. The display device of claim 11, wherein, The light emitting stack further comprises an electron blocking unit, in one of the light emitting stacks the green light emitting unit is located on a side of the electron blocking unit closer to the cathode layer, a positive projection of the electron blocking unit on the anode layer overlaps a positive projection of the green light emitting unit on the anode layer, the hole mobility of the electron blocking unit is greater than or equal to 10 -5 cm 2 / Vs and less than or equal to 10 -4 cm 2 / Vs.

16. The display device of claim 11, wherein, The light-emitting stack further comprises a hole transport layer, in one of the light-emitting stacks the green light-emitting unit is located on a side of the hole transport layer close to the cathode layer, the highest occupied molecular orbital energy level of the hole transport material of the hole transport layer is greater than or equal to -5.7 eV and less than or equal to -5.5 eV.

17. The display device of claim 16, wherein, The highest occupied molecular orbital energy level of the hole transport material of the hole transport layer is greater than or equal to -5.7 eV and less than or equal to -5.6 eV.

18. The display device of claim 11, wherein, The light emitting stack further comprises a hole transporting layer, in one of the light emitting stacks the green light emitting unit is located on the side of the hole transporting layer closer to the cathode layer, the hole transporting layer has a hole mobility greater than or equal to 10 -5 cm 2 / Vs and less than or equal to 10 -4 cm 2 / Vs.

19. The display device of claim 11, wherein, The number of the light-emitting stacks is multiple, the display panel further comprises a charge generation layer, the charge generation layer is located between two adjacent light-emitting stacks, each of the light-emitting stacks comprises the green light-emitting unit, the blue light-emitting unit and the red light-emitting unit.

20. The display device of claim 11, wherein, The green host material comprises at least one of a p-type green host material and an n-type green host material, the p-type green host material is selected from at least one of a carbazole compound and an indolocarbazole compound, and the n-type green host material is selected from at least one of a triazine compound, a diphenylfuran compound and a triphenylene compound.

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