Display panel and display device

Abstract

The embodiment of the invention provides a display panel and a display device. The display panel comprises a substrate; the light-emitting unit is arranged on one side of the substrate, and the light-emitting unit comprises a light-emitting layer; wherein the light-emitting layer comprises a host material and a guest material, and the dipole moment of the host material of the light-emitting layer of at least one light-emitting unit is 0.2 D-5. 0D. The dipole moment of the host material of the light-emitting layer of at least one light-emitting unit is 0.2 D-5. 0D, when the dipole moment of the host material is within the range, the light-emitting spectrum of the guest material can be adjusted, the light-emitting effect of the guest material can be improved, the display effect of the display panel is further improved, and the use effect of the display panel is improved. The light emitting effect of the object material is adjusted by adjusting the dipole moment of the subject material, the scheme is simple, and the use effect of the display panel can be improved.

Description

Technical Field

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

[0002] Organic Light Emitting Diode (OLED) and flat panel display devices based on technologies such as Light Emitting Diode (LED) have been widely used in various consumer electronic products such as mobile phones, televisions, laptops, desktop computers, etc. due to their advantages such as high image quality, power saving, thin body and wide application range, becoming the mainstream in display devices.

[0003] However, the performance of current OLED display products needs to be improved. Summary of the invention

[0004] Embodiments of the present application provide a display panel and a display device, aiming to improve the performance of the display panel.

[0005] An embodiment of the first aspect of the present application provides a display panel, comprising: a substrate; a light-emitting unit, arranged on one side of the substrate, the light-emitting unit comprising a light-emitting layer; wherein the light-emitting layer comprises a host material and a guest material, and the dipole moment of the host material of the light-emitting layer of at least one light-emitting unit is 0.2D~5.0D.

[0006] According to the implementation of the first aspect of the present application, the host material of at least one light-emitting unit includes a first hole-type host material and a second electron-type host material, and the dipole moment of the host material is 0.3D to 4.0D.

[0007] According to any of the aforementioned embodiments of the first aspect of the present application, the LUMO energy level of the first hole-type host material is higher than the LUMO energy level of the second electron-type host material.

[0008] According to any of the aforementioned embodiments of the first aspect of the present application, the HOMO energy level of the first hole-type host material is higher than the HOMO energy level of the second electron-type host material.

[0009] According to any of the aforementioned embodiments of the first aspect of the present application, in the host material of the same light-emitting unit, the mass ratio of the first hole-type host material to the second electron-type host material is 2:8 to 8:2.

[0010] According to any of the aforementioned embodiments of the first aspect of the present application, in the host material of the same light-emitting unit, the mass ratio of the first hole-type host material to the second electron-type host material is 4:6 to 6:4.

[0011] According to any of the aforementioned embodiments of the first aspect of the present application, the main material of at least one light-emitting unit also includes a third main material, the molecular polarity of the third main material is greater than or less than the molecular polarity of the first hole-type main material, and / or the molecular polarity of the third main material is greater than or less than the molecular polarity of the second electron-type main material.

[0012] According to any of the aforementioned embodiments of the first aspect of the present application, the molecular polarity of the third host material is greater than the one with the larger molecular polarity between the first hole-type host material and the second electron-type host material, or the molecular polarity of the third host material is less than the one with the smaller molecular polarity between the first hole-type host material and the second electron-type host material.

[0013] According to any of the aforementioned embodiments of the first aspect of the present application, the LUMO energy level of the third host material is higher than the LUMO energy level of the first hole-type host material.

[0014] According to any of the aforementioned embodiments of the first aspect of the present application, the HOMO energy level of the third host material is higher than the HOMO energy level of the first hole-type host material.

[0015] According to any of the aforementioned embodiments of the first aspect of the present application, the first hole-type host material and the second electron-type host material form an exciplex, and the T1 state energy level of the third host material is higher than the T1 state energy level of the exciplex.

[0016] According to any of the aforementioned embodiments of the first aspect of the present application, the T1 state energy level of the third host material is higher than the T1 state energy level of the guest material.

[0017] According to any of the aforementioned embodiments of the first aspect of the present application, the first hole-type host material and the second electron-type host material form an exciplex, and the S1 state energy level of the third host material is higher than the S1 state energy level of the exciplex.

[0018] According to any of the aforementioned embodiments of the first aspect of the present application, the S1 state energy level of the third host material is higher than the S1 state energy level of the guest material.

[0019] According to any of the aforementioned embodiments of the first aspect of the present application, the light-emitting unit includes a red light-emitting unit, a green light-emitting unit and a blue light-emitting unit, the main material of the red light-emitting unit includes a third main material, and the S1 state energy level of the third main material of the red light-emitting unit is greater than 2.60 eV; and / or,

[0020] The host material of the green light-emitting unit includes a third host material, and the S1 state energy level of the third host material of the green light-emitting unit is greater than 3.1 eV; and / or,

[0021] The host material of the blue light-emitting unit includes a third host material, and an S1 state energy level of the third host material of the blue light-emitting unit is greater than 3.1 eV.

[0022] According to any of the aforementioned embodiments of the first aspect of the present application, the third host material includes a polar compound or a non-polar compound.

[0023] According to any of the aforementioned embodiments of the first aspect of the present application, the third host material includes a polar compound, and the polar compound includes an aromatic compound.

[0024] According to any of the aforementioned embodiments of the first aspect of the present application, the aromatic compound included in the third host material includes a donor group and an acceptor group.

[0025] According to any of the aforementioned embodiments of the first aspect of the present application, the donor group includes at least one of a carbazole group, an aromatic amino group, a dibenzofuran group, a dibenzothiophene group, a naphthyl group, a phenanthrenyl group, a pyridyl group, an alkyl group, an alkoxy group, and a biphenyl group.

[0026] According to any of the aforementioned embodiments of the first aspect of the present application, the acceptor group includes at least one of diazine and triazine.

[0027] According to any of the aforementioned embodiments of the first aspect of the present application, the diazine includes at least one of pyridazine, pyrimidine, and pyrazine.

[0028] According to any of the aforementioned embodiments of the first aspect of the present application, the third host material includes a non-polar compound, and the non-polar compound includes an aromatic ring compound.

[0029] According to any of the aforementioned embodiments of the first aspect of the present application, the aromatic ring compound includes at least one of spirofluorene, biphenyl, and carbazole.

[0030] According to any of the aforementioned embodiments of the first aspect of the present application, the light-emitting layer includes a first sublayer, a second sublayer and a third sublayer stacked in a direction away from the substrate, and the doping concentration of the third main material of the first sublayer and / or the third sublayer is less than the doping concentration of the third main material of the second sublayer.

[0031] According to any of the aforementioned embodiments of the first aspect of the present application, the doping concentration of the third main material of the first sublayer and / or the third sublayer is 0.

[0032] According to any of the aforementioned embodiments of the first aspect of the present application, the first sublayer includes a first surface facing away from the second sublayer, the second sublayer includes a second surface facing the first sublayer and a third surface facing the third sublayer, the third sublayer includes a fourth surface facing away from the second sublayer, and the distance between the first surface and the second surface is smaller than the distance between the third surface and the fourth surface.

[0033] According to any of the aforementioned embodiments of the first aspect of the present application, the light-emitting unit further includes a first electrode and a second electrode, the first electrode is located on the side of the light-emitting layer facing the substrate, and the second electrode is located on the side of the light-emitting layer facing away from the substrate, the first electrode is an anode, and the second electrode is a cathode.

[0034] According to any of the aforementioned embodiments of the first aspect of the present application, the mass of the third host material accounts for 0.5% to 10% of the total mass of the light-emitting layer.

[0035] According to any of the aforementioned embodiments of the first aspect of the present application, the mass of the third host material accounts for 1% to 5% of the total mass of the light-emitting layer.

[0036] According to any of the aforementioned embodiments of the first aspect of the present application, the dipole moment of the first hole-type host material is 1.2D to 4.0D, and / or the dipole moment of the second electron-type host material is 0.3D to 2.5D.

[0037] According to any of the aforementioned embodiments of the first aspect of the present application, the light-emitting unit includes a red light-emitting unit, the red light-emitting unit includes a first hole-type host material and a second electron-type host material, the dipole moment of the first hole-type host material of the red light-emitting unit is 1.2D~3.0D, and / or the dipole moment of the second electron-type host material of the red light-emitting unit is 0.4D~1.2D.

[0038] According to any of the aforementioned embodiments of the first aspect of the present application, the dipole moment of the first hole-type host material of the red light-emitting unit is 1.2D to 1.7D, and / or the dipole moment of the second electron-type host material of the red light-emitting unit is 0.4D to 1.0D.

[0039] According to any of the aforementioned embodiments of the first aspect of the present application, the first hole-type host material of the red light-emitting unit includes at least one of carbazole, dibenzofuran, and a derivative of carbazole and dibenzofuran connected by a single bond or a benzene ring.

[0040] According to any of the aforementioned embodiments of the first aspect of the present application, the second electronic type host material of the red light-emitting unit includes polysubstituted triazines, dibenzothiophene, and derivatives of polysubstituted triazines and dibenzothiophene connected by single bonds or benzene rings.

[0041] According to any of the aforementioned embodiments of the first aspect of the present application, the first hole-type host material and the second electron-type host material of the red light-emitting unit form a first excited complex, the S1 state energy level of the first excited complex is 2.45eV~2.60eV, and / or the T1 state energy level of the first excited complex is 2.30eV~2.40eV.

[0042] According to any of the aforementioned embodiments of the first aspect of the present application, the HOMO energy level of the first hole-type host material of the red light-emitting unit is -5.40eV to -5.10eV; and / or, the LUMO energy level of the second electron-type host material of the red light-emitting unit is -3.10eV to -2.60eV.

[0043] According to any of the aforementioned embodiments of the first aspect of the present application, the HOMO energy level of the first hole-type host material of the red light-emitting unit is -5.30eV to -5.20eV; and / or, the LUMO energy level of the second electron-type host material of the red light-emitting unit is -3.00eV to -2.70eV.

[0044] According to any of the aforementioned embodiments of the first aspect of the present application, the light-emitting unit includes a green light-emitting unit, and the green light-emitting unit includes a first hole-type host material and a second electron-type host material, the dipole moment of the first hole-type host material of the green light-emitting unit is 2.0D~4.0D, and / or the dipole moment of the second electron-type host material of the green light-emitting unit is 0.3D~2.5D.

[0045] According to any of the aforementioned embodiments of the first aspect of the present application, the dipole moment of the first hole-type host material of the green light-emitting unit is 2.9D to 3.2D, and / or the dipole moment of the second electron-type host material of the green light-emitting unit is 1.5D to 1.8D.

[0046] According to any of the aforementioned embodiments of the first aspect of the present application, the first hole-type host material of the green light-emitting unit includes a bicarbazole compound.

[0047] According to any of the aforementioned embodiments of the first aspect of the present application, the first hole-type host material of the green light-emitting unit includes at least one of a dicarbazole and an N-carbazole compound, where N is a positive integer greater than or equal to 3.

[0048] According to any of the aforementioned embodiments of the first aspect of the present application, the second electronic type host material of the green light-emitting unit includes triphenylene or a polysubstituted triazine derivative.

[0049] According to any of the aforementioned embodiments of the first aspect of the present application, the first hole-type host material and the second electron-type host material of the green light-emitting unit form a second excited complex, the S1 state energy level of the second excited complex is 2.85eV~3.10eV, and / or the T1 state energy level of the second excited complex is 2.60eV~2.80eV.

[0050] According to any of the aforementioned embodiments of the first aspect of the present application, the HOMO energy level of the first hole-type host material of the green light-emitting unit is -5.50eV to -5.20eV; and / or, the LUMO energy level of the second electron-type host material of the green light-emitting unit is -2.90eV to -2.20eV.

[0051] According to any of the aforementioned embodiments of the first aspect of the present application, the HOMO energy level of the first hole-type host material of the green light-emitting unit is -5.40eV to -5.30eV; and / or, the LUMO energy level of the second electron-type host material of the green light-emitting unit is -2.80eV to -2.30eV.

[0052] According to any of the aforementioned embodiments of the first aspect of the present application, the light-emitting unit includes a blue light-emitting unit, the blue light-emitting unit includes a first hole-type host material and a second electron-type host material, the dipole moment of the first hole-type host material of the blue light-emitting unit is 1.5D to 3.5D, and / or the dipole moment of the second electron-type host material of the blue light-emitting unit is 0.5D to 2.5D.

[0053] According to any of the aforementioned embodiments of the first aspect of the present application, the dipole moment of the first hole-type host material of the blue light-emitting unit is 2.0D to 3.0D, and / or the dipole moment of the second electron-type host material of the blue light-emitting unit is 0.7D to 1.5D.

[0054] According to any of the aforementioned embodiments of the first aspect of the present application, the first hole-type host material of the blue light-emitting unit includes: at least one of biphenyl or dibenzofuran derivatives, carbazole or triphenylphosphine derivatives.

[0055] According to any of the aforementioned embodiments of the first aspect of the present application, the second electronic type host material of the blue light-emitting unit includes: at least one of pyridine, triazine, benzimidazole compounds, and nitrogen-containing heterocyclic compounds.

[0056] According to any of the aforementioned embodiments of the first aspect of the present application, the first hole-type host material and the second electron-type host material of the blue light-emitting unit form a mixture, the S1 state energy level of the mixture is 3.00eV~3.10eV, and / or the T1 state energy level of the mixture is 2.80eV~3.00eV.

[0057] According to any of the aforementioned embodiments of the first aspect of the present application, the HOMO energy level of the first hole-type host material of the blue light-emitting unit is -5.90eV to -5.40eV; and / or, the LUMO energy level of the second electron-type host material of the blue light-emitting unit is -3.00eV to -2.70eV.

[0058] According to any of the aforementioned embodiments of the first aspect of the present application, the HOMO energy level of the first hole-type host material of the blue light-emitting unit is -5.80eV to -5.50eV; and / or, the LUMO energy level of the second electron-type host material of the blue light-emitting unit is -3.00eV to -2.80eV.

[0059] According to any of the aforementioned embodiments of the first aspect of the present application, the main material of at least one light-emitting unit is a single main material, and the dipole moment of the main material is 1.5D to 5.0D, or the dipole moment of the main material is 0.2D to 1.5D.

[0060] According to any of the aforementioned embodiments of the first aspect of the present application, the dipole moment of the main material is 2.0D to 4.0D.

[0061] According to any of the aforementioned embodiments of the first aspect of the present application, the light-emitting unit includes a red light-emitting unit, a green light-emitting unit and a blue light-emitting unit, the mass of the guest material of the red light-emitting unit accounts for 1% to 4% of the total mass of the light-emitting layer; and / or, the mass of the guest material of the green light-emitting unit accounts for 5% to 15% of the total mass of the light-emitting layer; and / or, the mass of the guest material of the blue light-emitting unit accounts for 1% to 5% of the total mass of the light-emitting layer.

[0062] According to any of the aforementioned embodiments of the first aspect of the present application, the mass of the guest material of the red light-emitting unit accounts for 1.5% to 2.5% of the total mass of the light-emitting layer;

[0063] and / or, the mass of the guest material of the green light-emitting unit accounts for 8% to 10% of the total mass of the light-emitting layer;

[0064] And / or, the mass of the guest material of the blue light-emitting unit accounts for 1.5% to 2.5% of the total mass of the light-emitting layer.

[0065] According to any of the aforementioned embodiments of the first aspect of the present application, the light-emitting unit includes two or more light-emitting layers stacked in layers, and the dipole moment of the main material of at least one light-emitting layer of at least one light-emitting unit is 0.2D to 5.0D.

[0066] The embodiment of the first aspect of the present application further provides a light-emitting device, which includes a light-emitting layer, the light-emitting layer includes a host material and a guest material, and the dipole moment of the host material is 0.2D to 5.0D.

[0067] An embodiment of the first aspect of the present application also provides a display panel, comprising: a substrate; a light-emitting unit, arranged on one side of the substrate, the light-emitting unit comprising a red light-emitting unit, a green light-emitting unit and a blue light-emitting unit, the light-emitting unit comprising a light-emitting layer; wherein the light-emitting layer comprises a host material and a guest material, and the host material of at least one of the red light-emitting unit, the green light-emitting unit and the blue light-emitting unit comprises a first hole-type host material and a second electron-type host material, and the mass ratio of the first hole-type host material to the second electron-type host material is 2:8 to 8:2.

[0068] An embodiment of the second aspect of the present application further provides a display device, comprising the display panel provided by any of the above-mentioned embodiments of the first aspect.

[0069] In the display panel provided in the embodiment of the present application, the display panel includes a substrate and a light-emitting unit arranged on the substrate, and the light-emitting unit is used to realize the light-emitting display of the display panel. The light-emitting unit includes a light-emitting layer, and the light-emitting layer includes a host material and a guest material. The host material can capture electrons and holes to form excitons, and efficiently transfer the formed exciton energy to the guest material to promote the luminescence of the guest material. The dipole moment of the host material of the light-emitting layer of at least one light-emitting unit is 0.2D~5.0D. When the dipole moment of the host material is within the above range, the luminescence spectrum of the guest material can be adjusted to improve the luminescence effect of the guest material, thereby improving the display effect of the display panel and improving the use effect of the display panel. The embodiment of the present application adjusts the luminescence effect of the guest material by adjusting the dipole moment of the host material. The scheme is simple and can improve the use effect of the display panel. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Other features, objects and advantages of the present application will become more apparent by reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings, in which the same or similar reference numerals represent the same or similar features.

[0071] Figure 1 is a structural schematic diagram of a display panel provided in an embodiment of the present application;

[0072] Figure 2 is a schematic diagram of a layer structure of a display panel provided in an embodiment of the present application;

[0073] Figure 3 is a schematic diagram of an energy level structure of a display panel provided in an embodiment of the present application;

[0074] Figure 4 is a schematic diagram of an energy level structure of a display panel provided by another embodiment of the present application;

[0075] Figure 5 It is a peak diagram of a comparative example provided in the embodiment of the present application;

[0076] Figure 6 It is a half-peak width test curve diagram of the comparative example provided in the embodiment of the present application;

[0077] Figure 7 This is a test curve diagram of the half-peak width provided by another comparative example of the present application.

[0078] Description of reference numerals:

[0079] 100. Substrate;

[0080] 200, light-emitting unit; 210, light-emitting layer; 211, first sublayer; 212, second sublayer; 213, third sublayer; P1, first surface; P2, second surface; P3, third surface; P4, fourth surface; 220, first electrode; 230, second electrode;

[0081] 300, pixel definition layer; 310, pixel definition portion; 320, pixel opening;

[0082] 400. Encapsulation layer. DETAILED DESCRIPTION

[0083] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In the detailed description below, many specific details are proposed to provide a comprehensive understanding of the present application. However, it is obvious to those skilled in the art that the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating examples of the present application. In the accompanying drawings and the following description, at least some of the known structures and technologies are not shown to avoid unnecessary ambiguity in the present application; and, for clarity, the size of some structures may be exaggerated. In addition, the features, structures or characteristics described below may be combined in one or more embodiments in any suitable manner.

[0084] In the description of the present application, it should be noted that, unless otherwise specified, "multiple" means more than two; the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicating directions or positional relationships, are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0085] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of the embodiments of the present application. In the description of the present application, it should also be noted that, unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0086] In the process of realizing the present invention, the inventors discovered the following problems in the related technology: for OLED light-emitting devices, the luminescence spectrum of the guest material of its luminescent layer has an important influence on the various performances of the device. The luminescence spectrum of the guest material includes luminescence color, color purity, external quantum efficiency, etc. The luminescence spectrum of the guest material generally needs to be achieved through the design and adjustment of the molecular structure, but this method is costly and may cause changes in the electrical properties of the material molecules.

[0087] In order to solve the above technical problems, this application is proposed. In order to better understand this application, Figures 1 to 7 The display panel and the display device according to the embodiments of the present application are described in detail.

[0088] like Figure 1 and Figure 2 As shown, an embodiment of the first aspect of the present application provides a display panel, comprising: a substrate 100; a light-emitting unit 200, which is arranged on one side of the substrate 100, and the light-emitting unit 200 includes a light-emitting layer 210; wherein the light-emitting layer 210 includes a host material and a guest material, and the dipole moment of the host material of the light-emitting layer 210 of at least one light-emitting unit 200 is 0.2D~5.0D.

[0089] Optionally, the dipole moment of the host material of the light-emitting layer 210 of at least one light-emitting unit 200 is 0.2D, 0.25D, 0.40D, 0.42D, 3.0D, 4.0D, 5.0D, etc. The common unit of dipole moment is Debye (D).

[0090] In the display panel provided in the embodiment of the present application, the display panel includes a substrate 100 and a light-emitting unit 200 arranged on the substrate 100, and the light-emitting unit 200 is used to realize the light-emitting display of the display panel. The light-emitting unit 200 includes a light-emitting layer 210, and the light-emitting layer 210 includes a host material and a guest material. The host material can capture electrons and holes to form excitons, and efficiently transfer the formed exciton energy to the guest material to promote the luminescence of the guest material. The dipole moment of the host material of the light-emitting layer 210 of at least one light-emitting unit 200 is 0.2D~5.0D. When the dipole moment of the host material is within the above range, the luminescence spectrum of the guest material can be adjusted to improve the luminescence effect of the guest material, thereby improving the display effect of the display panel and improving the use effect of the display panel. The embodiment of the present application adjusts the luminescence effect of the guest material by adjusting the dipole moment of the host material, rather than by adjusting the molecular structure of the host material or the guest material. The scheme is simple and can improve the use effect of the display panel.

[0091] Optionally, the light-emitting unit 200 includes a red light-emitting unit, a green light-emitting unit and a blue light-emitting unit, the red light-emitting unit is used to emit red light, the green light-emitting unit is used to emit green light, and the blue light-emitting unit is used to emit blue light, so as to realize color display of the display panel.

[0092] Optionally, the display panel includes a pixel definition layer 300, the pixel definition layer 300 is disposed on the substrate 100, the pixel definition layer 300 includes a pixel defining portion 310 and a pixel opening 320, and at least a portion of the light emitting layer 210 may be located in the pixel opening 320. Optionally, the light emitting unit 200 further includes a first electrode 220 and a second electrode 230. Optionally, the display panel further includes an encapsulation layer 400.

[0093] Optional, such as Figure 2 As shown, the light-emitting unit 200 further includes an electron injection layer (EIL) and an electron transport layer (ETL) sequentially located between the second electrode 230 and the light-emitting layer 210, and a hole injection layer (HIL) and a hole transport layer (HTL) sequentially located between the first electrode 220 and the light-emitting layer 210. In other embodiments, the light-emitting unit 200 may further include a hole blocking layer and an electron blocking layer.

[0094] Optionally, the dipole moment of the main material of the light-emitting layer 210 of at least one light-emitting unit 200 is 0.2D to 5.0D, and the dipole moment of the main material of the light-emitting layer 210 of at least one of the multiple red light-emitting units is 0.2D to 5.0D, or the dipole moment of the main material of the light-emitting layer 210 of at least one of the multiple green light-emitting units is 0.2D to 5.0D, or the dipole moment of the main material of the light-emitting layer 210 of at least one of the multiple blue light-emitting units is 0.2D to 5.0D. Or the dipole moments of the main materials of the multiple light-emitting layers 210 are all 0.2D to 5.0D, so as to further improve the display effect of the display panel.

[0095] There are many ways to set the host material, for example, the host material is a dual host material, in some optional embodiments, the host material of at least one light-emitting unit 200 includes a first hole-type host material and a second electron-type host material, and the dipole moment of the host material is 0.3D to 4.0D. For example, the dipole moment of the host material is 0.3D, 0.8D, 1.2D, 2.3D, 3.5D, 4.0D, etc.

[0096] In these optional embodiments, the host material includes a first hole-type host material and a second electron-type host material, and the two host materials can better capture holes and electrons to form excitons, which can improve the luminous efficiency. When the host material is a dual host material, that is, the host material includes a first hole-type host material and a second electron-type host material, when the dipole moment of the host material is within the above range, the guest material has a better spectrum and luminous efficiency, which can improve the display effect of the display panel.

[0097] Optional, such as Figure 3 As shown, the lowest unoccupied molecular orbital (LUMO) energy level and the highest occupied molecular orbital (HOMO) energy level of the first hole-type host material and the second electron-type host material can be different, so that the first hole-type host material and the second electron-type host material can play different roles.

[0098] For example, the LUMO energy level of the first hole-type host material is higher than the LUMO energy level of the second electron-type host material. The higher LUMO energy level of the first hole-type host material means that the energy of the lowest unoccupied orbital of the first hole-type host material is higher, and it is easier to donate electrons.

[0099] Optionally, the HOMO energy level of the first hole-type host material is higher than the HOMO energy level of the second electron-type host material. The HOMO energy level of the second electron-type host material is lower, so the second electron-type host material is more likely to accept electrons.

[0100] In some optional embodiments, in the host material of the same light-emitting unit 200, the mass ratio of the first hole-type host material to the second electron-type host material is 2:8 to 8:2. For example, the mass ratio of the first hole-type host material to the second electron-type host material is 2:8, 3:7, 4:6, 5:5, 6:4, 8:2, etc. When the mass ratio of the first hole-type host material to the second electron-type host material is within the above range, it can improve the situation that one of the first hole-type host material and the second electron-type host material has too much mass and the other has too little mass, which affects the injection and transmission of electrons or holes in the host material.

[0101] Optionally, in the host material of the same light-emitting unit 200, the mass ratio of the first hole-type host material to the second electron-type host material is 4:6 to 6:4. For example, the mass ratio of the first hole-type host material to the second electron-type host material is 4:6, 4.5:5.5, 5:5, 5.5:4.5, 6:4, etc. The mass ratio of the first hole-type host material to the second electron-type host material is within a suitable range to ensure the transmission and injection of holes or electrons.

[0102] In some optional embodiments, the main material of at least one light-emitting unit 200 also includes a third main material, the molecular polarity of the third main material is greater than or less than the molecular polarity of the first hole-type main material, and / or the molecular polarity of the third main material is greater than or less than the molecular polarity of the second electron-type main material.

[0103] In these optional embodiments, the main materials of at least one light-emitting unit 200 include three main materials: a first hole-type main material, a second electron-type main material and a third main material, and the molecular polarity of the third main material is different from the molecular polarity of the first hole-type main material and the second electron-type main material, so that the third main material can change the overall molecular polarity of the main material and improve the overall dipole moment of the main material, thereby improving the spectral characteristics of the guest material and improving the display effect of the display panel.

[0104] Optionally, the molecular polarity of the third host material is greater than the larger molecular polarity of the first hole-type host material and the second electron-type host material, or the molecular polarity of the third host material is less than the smaller molecular polarity of the first hole-type host material and the second electron-type host material.

[0105] For example, when the molecular polarity of the first hole-type host material is greater than the molecular polarity of the second electron-type host material, the molecular polarity of the third host material can be greater than the molecular polarity of the first hole-type host material, or the molecular polarity of the third host material can be less than the molecular polarity of the second electron-type host material, so that the addition of the third host material can increase or decrease the overall molecular polarity of the host material.

[0106] Alternatively, when the molecular polarity of the first hole-type host material is smaller than that of the second electron-type host material, the molecular polarity of the third host material may be smaller than that of the first hole-type host material, or, the molecular polarity of the third host material may be greater than that of the second electron-type host material, so that the addition of the third host material can increase or decrease the overall molecular polarity of the host material.

[0107] Optionally, the LUMO energy level of the third host material is higher than the LUMO energy level of the first hole-type host material. The LUMO energy level of the third host material is different from the LUMO energy level of the first hole-type host material, so that the third host material is difficult to affect the transmission of carriers in the first hole-type host material and the transfer of exciton energy.

[0108] Optionally, the HOMO energy level of the third host material is higher than the HOMO energy level of the first hole-type host material. The HOMO energy level of the third host material is different from the HOMO energy level of the first hole-type host material, so that the third host material is difficult to affect the transmission of carriers in the first hole-type host material and the transfer of exciton energy.

[0109] Optionally, the first hole-type host material and the second electron-type host material may be mixed to generate an exciplex, such as Figure 4 As shown, the T1 state energy level of the third host material is higher than the T1 state energy level of the exciplex, that is, the triplet state energy level of the third host material is higher than the triplet state energy level of the exciplex. This arrangement makes it easier to control the dipole moment, thereby facilitating adjustment of the luminescence spectrum performance of the guest material, and also helps to improve the luminescence efficiency of the device.

[0110] Optionally, the T1 state energy level of the third host material is higher than the T1 state energy level of the guest material, so that energy can be efficiently transferred from the host material to the guest material.

[0111] In some optional embodiments, the S1 state energy level of the third host material is higher than the S1 state energy level of the exciplex. This arrangement makes it easier to adjust the dipole moment, thereby facilitating adjustment of the luminescence spectrum performance of the guest material, and also helps to improve the luminescence efficiency of the device.

[0112] Optionally, the S1 state energy level of the third host material is higher than the S1 state energy level of the guest material.

[0113] Please refer to the above, the light-emitting unit 200 includes a red light-emitting unit, a green light-emitting unit and a blue light-emitting unit. Optionally, the main material of the red light-emitting unit includes a third main material, and the S1 state energy level of the third main material of the red light-emitting unit is greater than 2.60eV, and / or, the main material of the green light-emitting unit includes a third main material, and the S1 state energy level of the third main material of the green light-emitting unit is greater than 3.1eV; and / or, the main material of the blue light-emitting unit includes a third main material, and the S1 state energy level of the third main material of the blue light-emitting unit is greater than 3.1eV. When the third main material is disposed in light-emitting units 200 of different colors, the S1 state energy level is slightly different, so that the third main material can be adapted to light-emitting units 200 of different colors.

[0114] There are many ways to set the third host material, and the third host material can be a polar compound or a non-polar compound. When the third host material is a polar compound, the third host material can increase the dipole moment of the host material after being added to the host material. When the third host material is a non-polar compound, the third host material can reduce the dipole moment of the host material after being added to the host material. Therefore, the third host material can change the dipole moment of the host material by selecting a polar compound or a non-polar compound.

[0115] When the third host material is a polar compound material, the polar compound may be an aromatic compound. For example, the aromatic compound included in the third host material includes a donor group and an acceptor group, so that the third host material has molecular polarity and can change the dipole moment of the host material.

[0116] Optionally, the donor group may include at least one of carbazole, arylamino, dibenzofuran, dibenzothiophene, naphthyl, phenanthryl, pyridyl, alkyl, alkoxy, and biphenyl. Optionally, the acceptor group may be at least one of diazine and triazine. Optionally, the diazine includes at least one of pyridazine, pyrimidine, and pyrazine.

[0117] When the third host material includes a non-polar compound, the non-polar compound may include an aromatic ring compound, for example, the aromatic ring compound includes at least one of spirofluorene, biphenyl, and carbazole.

[0118] The third host material may be uniformly mixed in the light-emitting layer 210. Alternatively, in some other optional embodiments, the light-emitting layer 210 includes a first sublayer 211, a second sublayer 212, and a third sublayer 213 stacked in a direction away from the substrate 100, and the doping concentration of the third host material in the first sublayer 211 and / or the third sublayer 213 is less than the doping concentration of the third host material in the second sublayer 212.

[0119] In these optional embodiments, electrons and holes are more likely to combine in the second sublayer 212 to form excitons, and the doping concentration of the third main material in the second sublayer 212 is relatively high, so that the third main material can better improve the performance of the second sublayer 212 and enhance the luminous effect of the display panel.

[0120] Optionally, the first sublayer 211 and the third sublayer 213 may be doped with a small amount of the third host material, or the doping concentration of the third host material of the first sublayer 211 and / or the third sublayer 213 may be 0, so as to reduce the manufacturing cost of the light-emitting layer 210 .

[0121] Optionally, the first sublayer 211 includes a first surface P1 facing away from the second sublayer 212, the second sublayer 212 includes a second surface P2 facing the first sublayer 211 and a third surface P3 facing the third sublayer 213, the third sublayer 213 includes a fourth surface P4 facing away from the second sublayer 212, and the distance between the first surface P1 and the second surface P2 is smaller than the distance between the third surface P3 and the fourth surface P4. That is, the distance between the second sublayer 212 and the substrate 100 is closer, and more excitons are usually generated on the anode side, making the distance between the second sublayer 212 and the substrate 100 closer, so that the third host material is adapted to the position of the excitons, and the performance of the second sublayer 212 can be better improved.

[0122] Optionally, the light-emitting unit 200 further includes a first electrode 220 and a second electrode 230, wherein the first electrode 220 is located on the side of the light-emitting layer 210 facing the substrate 100, and the second electrode 230 is located on the side of the light-emitting layer 210 facing away from the substrate 100, the first electrode 220 is an anode, and the second electrode 230 is a cathode. The first electrode 220 is an anode, that is, the electrode on the side of the light-emitting layer 210 facing the substrate 100 is an anode, and the distance between the second sublayer 212 and the anode is closer, thereby making the third host material fit the position of the exciton, and the performance of the second sublayer 212 can be better improved.

[0123] Optionally, the thicknesses of the first sublayer 211 , the second sublayer 212 , and the third sublayer 213 may be the same or different.

[0124] In some optional embodiments, the mass of the third host material accounts for 0.5% to 10% of the total mass of the light-emitting layer 210. For example, the mass of the third host material accounts for 0.5%, 1.2%, 2.5%, 5.0%, 7.8%, 9.0%, 10.0%, etc. of the total mass of the light-emitting layer 210, so as to prevent the third host material from accounting for too large a proportion and affecting the content of the first hole-type host material and the second electron-type host material, thereby affecting the performance of the light-emitting layer 210; it can also improve the adjustment of the dipole moment of the host material by the third host material due to a small proportion.

[0125] Optionally, the mass of the third host material accounts for 1% to 5% of the total mass of the materials of the light-emitting layer 210, for example, the mass of the third host material accounts for 1.0%, 1.2%, 2.5%, 3.4%, 5.0% etc. of the total mass of the light-emitting layer 210, so that the proportion of the third host material is within a more appropriate range.

[0126] In some optional embodiments, the dipole moment of the first hole-type host material is 1.2D to 4.0D, specifically, it can be 1.2D, 1.5D, 2.0D, 2.5D, 3.0D, 3.5D or 4.0D; and / or, the dipole moment of the second electron-type host material is 0.3D to 2.5D, specifically, it can be 0.3D, 0.5D, 0.8D, 1.0D, 1.5D, 2.0D or 2.5D.

[0127] In some optional embodiments, the red light-emitting unit includes a first hole-type host material and a second electron-type host material, the dipole moment of the first hole-type host material of the red light-emitting unit is 1.2D~3.0D, and / or the dipole moment of the second electron-type host material of the red light-emitting unit is 0.4D~1.2D.

[0128] For example, the dipole moment of the first hole-type host material of the red light-emitting unit is 1.2D, 1.5D, 2.0D, 2.3D, 3.0D, etc., and / or the dipole moment of the second electron-type host material of the red light-emitting unit is 0.4D, 0.8D, 0.9D, 1.0D, 1.2D, etc., so that the red light-emitting unit has a better spectral range.

[0129] Optionally, the dipole moment of the first hole-type host material of the red light-emitting unit is 1.2D to 1.7D, and / or the dipole moment of the second electron-type host material of the red light-emitting unit is 0.4D to 1.0D. For example, the dipole moment of the first hole-type host material of the red light-emitting unit is 1.2D, 1.5D, 1.55D, 1.6D, 1.7D, etc., and / or the dipole moment of the second electron-type host material of the red light-emitting unit is 0.4D, 0.5D, 0.8D, 0.9D, 1.0D, etc., so that the red light-emitting unit has a better spectral range.

[0130] Optionally, the first hole-type host material of the red light-emitting unit includes at least one of carbazole, dibenzofuran, and a derivative formed by connecting carbazole and dibenzofuran through a single bond or a benzene ring. Specifically, carbazole and dibenzofuran can be connected through a single bond or a benzene ring to form a derivative, and the first hole-type host material can include carbazole, dibenzofuran, and a derivative formed by the two.

[0131] Carbazole is a tricyclic aromatic compound consisting of two benzene rings and one pyrrole ring. Carbazole has high thermal and chemical stability. Carbazole also has good hole transport properties.

[0132] Dibenzofuran is a polycyclic aromatic compound consisting of two benzene rings and one furan ring. Dibenzofuran has good thermal and chemical stability. Dibenzofuran has good hole transport properties.

[0133] Optionally, the first hole-type host material of the red light-emitting unit may include:

[0134]

[0135] Optionally, the second electronic type host material of the red light emitting unit includes a polysubstituted triazine, dibenzothiophene, and a derivative formed by connecting a polysubstituted triazine and dibenzothiophene through a single bond or a benzene ring. Specifically, the polysubstituted triazine and dibenzothiophene can be connected through a single bond or a benzene ring to form a derivative. The second electronic type host material may include at least one of a polysubstituted triazine, dibenzothiophene, and a derivative of the two.

[0136] Triazine is a six-membered ring compound, composed of three carbon atoms and three nitrogen atoms, and has a highly conjugated structure. Triazine has high thermal stability and chemical stability. Triazine has good electron accepting ability and electron transport performance, and can improve the device performance of the light-emitting layer 210.

[0137] Dibenzothiophene is a polycyclic aromatic compound consisting of two benzene rings and one thiophene ring. Dibenzothiophene has good thermal stability and chemical stability. Dibenzothiophene also has good electron transport properties, which can improve the device performance of the light-emitting layer 210.

[0138] Optionally, the second electronic type host material of the red light-emitting unit includes at least one of the following materials:

[0139]

[0140] Optionally, the S1 state energy level of the exciplex of the red light-emitting unit is 2.45eV to 2.60eV, that is, the S1 state energy level of the first exciplex is 2.45eV to 2.60eV; and / or, the T1 state energy level of the exciplex of the red light-emitting unit is 2.30eV to 2.40eV, that is, the T1 state energy level of the first exciplex is 2.30eV to 2.40eV. For example, the S1 state energy level of the exciplex of the red light-emitting unit is 2.45eV, 2.47eV, 2.49eV, 2.50eV, 2.56eV, 2.60eV, etc., and / or, the T1 state energy level of the exciplex of the red light-emitting unit is 2.30eV, 2.31eV, 2.35eV, 2.37eV, 2.40eV, etc., to ensure the device performance of the red light-emitting unit.

[0141] Optionally, the HOMO energy level of the first hole-type host material of the red light-emitting unit is -5.40eV to -5.10eV; and / or, the LUMO energy level of the second electron-type host material of the red light-emitting unit is -3.10eV to -2.60eV, for example, the HOMO energy level of the first hole-type host material of the red light-emitting unit is -5.40eV, -5.35eV, -5.20eV, -5.15eV, -5.10eV, etc., and / or, the LUMO energy level of the second electron-type host material of the red light-emitting unit is -3.10eV, -3.00eV, -2.80eV, -2.70eV, -2.60eV, etc., so that the host material of the red light-emitting unit has good electron and hole transport capabilities.

[0142] Optionally, the HOMO energy level of the first hole-type host material of the red light-emitting unit is -5.30eV to -5.20eV; and / or, the LUMO energy level of the second electron-type host material of the red light-emitting unit is -3.00eV to -2.70eV, for example, the HOMO energy level of the first hole-type host material of the red light-emitting unit is -5.30eV, -5.28eV, -5.27eV, -5.26eV, -5.20eV, etc., and / or, the LUMO energy level of the second electron-type host material of the red light-emitting unit is -3.00eV, -2.90eV, -2.80eV, -2.75eV, -2.70eV, etc., so that the host material of the red light-emitting unit has good electron and hole transport capabilities.

[0143] In some optional embodiments, the green light-emitting unit includes a first hole-type host material and a second electron-type host material, the dipole moment of the first hole-type host material of the green light-emitting unit is 2.0D~4.0D, and / or the dipole moment of the second electron-type host material of the green light-emitting unit is 0.3D~2.5D.

[0144] For example, the dipole moment of the first hole-type main material of the green light-emitting unit is 2.0D, 2.1D, 2.5D, 3.0D, 4.0D, etc., and / or the dipole moment of the second electron-type main material of the green light-emitting unit is 0.3D, 0.8D, 0.9D, 1.0D, 1.2D, 2.0D, 2.5D, etc., so that the green light-emitting unit has a better spectral range.

[0145] Optionally, the dipole moment of the first hole-type host material of the green light-emitting unit is 2.9D to 3.2D, and / or the dipole moment of the second electron-type host material of the green light-emitting unit is 1.5D to 1.8D. For example, the dipole moment of the first hole-type host material of the green light-emitting unit is 2.9D, 2.91D, 3.0D, 3.1D, 3.2D, etc., and / or the dipole moment of the second electron-type host material of the green light-emitting unit is 1.5D, 1.55D, 1.6D, 1.7D, 1.8D, etc., so that the green light-emitting unit has a better spectral range.

[0146] Optionally, the first hole-type host material of the green light-emitting unit includes a bicarbazole compound, for example, the first hole-type host material of the green light-emitting unit includes at least one of a dicarbazole and an N-bicarbazole compound, wherein N is a positive integer greater than or equal to 3. Bicarbazole compounds are used as the material of the light-emitting layer 210 to improve the luminous efficiency, stability and life of the light-emitting layer 210.

[0147] Optionally, the second electron-type host material of the green light-emitting unit includes triphenylene or a multi-substituted triazine derivative.

[0148] Triphenylene is a polycyclic aromatic compound consisting of three benzene rings connected by a conjugated system to form a planar tricyclic structure. Triphenylene has high thermal and chemical stability and is not easily oxidized. Triphenylene has good electron transport properties and high carrier mobility, and has strong fluorescence properties, which can improve the performance and light-emitting effect of the device.

[0149] The polysubstituted triazine derivatives have high thermal stability and chemical stability, and have good electron accepting ability, electron transport performance and good fluorescence performance, which can improve the performance and light output effect of the device.

[0150] Optionally, the first hole-type host material of the green light-emitting unit includes at least one of the following materials:

[0151]

[0152] Optionally, the second electron-type host material of the green light-emitting unit includes at least one of the following materials:

[0153]

[0154] Optionally, the first hole-type host material and the second electron-type host material of the green light-emitting unit form an excited complex, and the S1 state energy level of the excited complex is 2.85eV~3.10eV, that is, the S1 state energy level of the second excited complex is 2.85eV~3.10eV, and / or, the T1 state energy level of the excited complex of the green light-emitting unit is 2.60eV~2.80eV, that is, the T1 state energy level of the second excited complex is 2.60eV~2.80eV. For example, the S1 state energy level of the excited complex of the green light-emitting unit is 2.85eV, 2.89eV, 2.91eV, 2.93eV, 3.0eV, 3.10eV, etc., and / or the T1 state energy level of the excited complex of the green light-emitting unit is 2.60eV, 2.65eV, 2.70eV, 2.72eV, 2.80eV, etc., to ensure the device performance of the green light-emitting unit.

[0155] Optionally, the HOMO energy level of the first hole-type host material of the green light-emitting unit is -5.50eV to -5.20eV; and / or, the LUMO energy level of the second electron-type host material of the green light-emitting unit is -2.90eV to -2.20eV, for example, the HOMO energy level of the first hole-type host material of the green light-emitting unit is -5.50eV, -5.28eV, -5.27eV, -5.26eV, -5.20eV, etc., and / or, the LUMO energy level of the second electron-type host material of the green light-emitting unit is -2.90eV, -2.80eV, -2.75eV, 2.73eV, -2.20eV, etc., so that the host material of the green light-emitting unit has good electron and hole transport capabilities.

[0156] Optionally, the HOMO energy level of the first hole-type host material of the green light-emitting unit is -5.40eV to -5.30eV; and / or, the LUMO energy level of the second electron-type host material of the green light-emitting unit is -2.80eV to -2.30eV, for example, the HOMO energy level of the first hole-type host material of the green light-emitting unit is -5.40eV, -5.38eV, -5.37eV, -5.36eV, -5.30eV, etc., and / or, the LUMO energy level of the second electron-type host material of the green light-emitting unit is -2.80eV, -2.78eV, -2.75eV, 2.73eV, -2.30eV, etc., so that the host material of the green light-emitting unit has good electron and hole transport capabilities.

[0157] In some optional embodiments, the blue light-emitting unit includes a first hole-type host material and a second electron-type host material, the dipole moment of the first hole-type host material of the blue light-emitting unit is 1.5D~3.5D, and / or the dipole moment of the second electron-type host material of the blue light-emitting unit is 0.5D~2.5D.

[0158] For example, the dipole moment of the first hole-type host material of the blue light-emitting unit is 1.5D, 2.1D, 2.5D, 3.0D, 3.5D, etc., and / or the dipole moment of the second electron-type host material of the blue light-emitting unit is 0.5D, 0.8D, 0.9D, 1.0D, 2.5D, etc., so that the blue light-emitting unit has a better spectral range.

[0159] Optionally, the dipole moment of the first hole-type host material of the blue light-emitting unit is 2.0D to 3.0D, and / or the dipole moment of the second electron-type host material of the blue light-emitting unit is 0.7D to 1.5D. For example, the dipole moment of the first hole-type host material of the blue light-emitting unit is 2.0D, 2.1D, 2.2D, 2.8D, 3.0D, etc., and / or the dipole moment of the second electron-type host material of the blue light-emitting unit is 0.7D, 0.8D, 1.0D, 1.2D, 1.5D, etc., so that the blue light-emitting unit has a better spectral range.

[0160] Optionally, the first hole-type host material of the blue light-emitting unit includes: at least one of biphenyl or dibenzofuran derivatives, carbazole or triphenylphosphine derivatives. Optionally, the second electron-type host material of the blue light-emitting unit includes: at least one of pyridine, triazine, benzimidazole compounds, and nitrogen-containing heterocyclic compounds. To ensure the performance of the blue light-emitting device.

[0161] Optionally, the first hole-type host material of the blue light-emitting unit includes at least one of the following materials:

[0162]

[0163] The second electron-type host material of the blue light-emitting unit includes at least one of the following materials:

[0164]

[0165] Optionally, the first hole-type host material and the second electron-type host material of the blue light-emitting unit form a mixture, and the S1 state energy level of the mixture is 3.0eV~3.10eV, and / or the T1 state energy level of the mixture of the blue light-emitting unit is 2.80eV~3.00eV, for example, the S1 state energy level of the mixture of the blue light-emitting unit is 3.0eV, 3.05eV, 3.08eV, 3.082eV, 3.9eV, 3.10eV, etc., and / or the T1 state energy level of the mixture of the blue light-emitting unit is 2.80eV, 2.85eV, 2.90eV, 2.92eV, 3.00eV, etc., to ensure the device performance of the blue light-emitting unit.

[0166] Optionally, the HOMO energy level of the first hole-type host material of the blue light-emitting unit is -5.90eV to -5.40eV; and / or, the LUMO energy level of the second electron-type host material of the blue light-emitting unit is -3.00eV to -2.70eV, for example, the HOMO energy level of the first hole-type host material of the blue light-emitting unit is -5.90eV, -5.88eV, -5.67eV, -5.56eV, -5.40eV, etc., and / or, the LUMO energy level of the second electron-type host material of the blue light-emitting unit is -3.00eV, -2.80eV, -2.75eV, 2.73eV, -2.70eV, etc., so that the host material of the blue light-emitting unit has good electron and hole transport capabilities.

[0167] Optionally, the HOMO energy level of the first hole-type host material of the blue light-emitting unit is -5.80eV to -5.50eV; and / or, the LUMO energy level of the second electron-type host material of the blue light-emitting unit is -3.00eV to -2.80eV, for example, the HOMO energy level of the first hole-type host material of the blue light-emitting unit is -5.80eV, -5.78eV, -5.77eV, -5.76eV, -5.50eV, etc., and / or, the LUMO energy level of the second electron-type host material of the blue light-emitting unit is -3.00eV, -2.98eV, -2.85eV, 2.83eV, -2.80eV, etc., so that the host material of the blue light-emitting unit has good electron and hole transport capabilities.

[0168] In other optional embodiments, the main body material of at least one light-emitting unit 200 may also be a single main body material, and the single main body material may be a large dipole moment material, for example, the dipole moment of the main body material is 1.5D to 5.0D, for example, the dipole moment of the main body material is 1.5D, 1.8D, 2.3D, 4.2D, 5.0D. Alternatively, the single main body material may be a small dipole moment material, for example, the dipole moment of the main body material is 0.2D to 1.5D, for example, the dipole moment of the main body material is 0.2D, 0.8D, 1.1D, 1.3D, 1.5D, etc., so that the main body material has good electron and hole transport properties.

[0169] Optionally, when a large dipole moment material is selected as a single host material, the dipole moment of the host material can also be 2.0D to 4.0D. For example, the dipole moment of the host material is 2.0D, 2.5D, 2.8D, 3.2D, or 4.0D, so that the host material has good electron and hole transport properties.

[0170] In some optional embodiments, the weight proportions of the guest materials in the red light-emitting unit, the green light-emitting unit, and the blue light-emitting unit may be slightly different, for example, the weight of the guest material of the red light-emitting unit accounts for 1% to 4% of the total weight of the light-emitting layer 210; and / or, the weight of the guest material of the green light-emitting unit accounts for 5% to 15% of the total weight of the light-emitting layer 210; and / or, the weight of the guest material of the blue light-emitting unit accounts for 1% to 5% of the total weight of the light-emitting layer 210. This can meet the light-emitting requirements of light-emitting units 200 of different colors.

[0171] For example, the mass of the guest material of the red light-emitting unit accounts for 1%, 1.5%, 2.0%, 2.3%, 3.5%, 4.0%, etc. of the total mass of the light-emitting layer 210. The mass of the guest material of the green light-emitting unit accounts for 5%, 5.5%, 6.0%, 7.3%, 8.5%, 10.5%, 15.0%, etc. of the total mass of the light-emitting layer 210. The mass of the guest material of the blue light-emitting unit accounts for 1%, 1.5%, 2.0%, 2.3%, 3.5%, 5.0%, etc. of the total mass of the light-emitting layer 210.

[0172] Optionally, the mass of the guest material of the red light-emitting unit accounts for 1.5% to 2.5% of the total mass of the light-emitting layer 210; and / or, the mass of the guest material of the green light-emitting unit accounts for 8% to 10% of the total mass of the light-emitting layer 210; and / or, the mass of the guest material of the blue light-emitting unit accounts for 1.5% to 2.5% of the total mass of the light-emitting layer 210. This makes the weight proportion of the guest materials in the light-emitting units 200 of different colors more appropriate.

[0173] For example, the mass of the guest material of the red light-emitting unit accounts for 1%, 1.5%, 2.0%, 2.3%, 2.45%, 2.5%, etc. of the total mass of the light-emitting layer 210. The mass of the guest material of the green light-emitting unit accounts for 8%, 8.5%, 9.0%, 9.3%, 9.5%, 10.0%, etc. of the total mass of the light-emitting layer 210. The mass of the guest material of the blue light-emitting unit accounts for 1.5%, 1.8%, 2.0%, 2.3%, 2.5%, etc. of the total mass of the light-emitting layer 210.

[0174] In some optional embodiments, the light-emitting unit 200 includes two or more light-emitting layers 210 stacked together, and the dipole moment of the main material of at least one light-emitting layer 210 of at least one light-emitting unit 200 is 0.2D to 5.0D. That is, the display panel is a stacked device, and the dipole moment of the main material of at least one of the multiple light-emitting layers 210 stacked together in the stacked device meets the above range requirements, which can improve the light-emitting effect of the stacked device.

[0175] Optionally, the guest material includes a transition metal complex, including but not limited to an iridium complex, the cyclometallated ligand of the iridium complex includes a C^N ligand, a C^C ligand, etc., the auxiliary ligand includes a N^N ligand, an O^O ligand, a C^N ligand, etc., and the ligand can be a derivative connected by a single bond or a benzene ring of a quinolyl, naphthyl, pyrimidinyl, pyrimidothiphenyl, phenylpyridinyl, bipyridinyl, biphenyl, benzofuranyl, etc.; the guest material can also be a resonance fluorescent dye, including a boron nitrogen resonance type, a boron oxygen resonance type, a carbonyl-oxygen resonance type, etc. Optionally, the specific material structure is as follows:

[0176]

[0177]

[0178] like Figures 1 to 4 As shown, the embodiment of the first aspect of the present application further provides a light-emitting device, which includes a light-emitting layer 210, and the light-emitting layer 210 includes a host material and a guest material, and the dipole moment of the host material is 0.2D~5.0D.

[0179] In an embodiment of the present application, the light-emitting device includes a light-emitting layer 210, and the light-emitting layer 210 includes a host material and a guest material. The host material can capture electrons and holes to form excitons, and efficiently transfer the formed exciton energy to the guest material to promote the luminescence of the guest material. The dipole moment of the host material is 0.2D to 5.0D. When the dipole moment of the host material is within the above range, the luminescence spectrum of the guest material can be adjusted to improve the luminescence effect of the guest material, thereby improving the display effect of the display panel when the light-emitting device is applied to the display panel, and improving the use effect of the display panel. The embodiment of the present application adjusts the luminescence effect of the guest material by adjusting the dipole moment of the host material. The scheme is simple and can improve the use effect of the display panel.

[0180] The setting method of the main material can be found above and will not be repeated here.

[0181] like Figures 1 to 4 As shown, an embodiment of the first aspect of the present application also provides a display panel, comprising: a substrate 100; a light-emitting unit 200, which is arranged on one side of the substrate 100, the light-emitting unit 200 includes a red light-emitting unit, a green light-emitting unit and a blue light-emitting unit, and the light-emitting unit 200 includes a light-emitting layer 210; wherein the light-emitting layer 210 includes a host material and a guest material, and the host material of at least one of the red light-emitting unit, the green light-emitting unit and the blue light-emitting unit includes a first hole-type host material, a second electron-type host material and a third host material, the molecular polarity of the third host material is greater than or less than the molecular polarity of the first hole-type host material, and / or the molecular polarity of the third host material is greater than or less than the molecular polarity of the second electron-type host material.

[0182] In an embodiment of the present application, the main material includes three materials: a first hole-type main material, a second electron-type main material and a third main material, and the molecular polarity of the third main material is different from the molecular polarity of the first hole-type main material and the second electron-type main material, so that the third main material can change the overall molecular polarity of the main material and improve the overall dipole moment of the main material, thereby improving the spectral characteristics of the guest material and improving the display effect of the display panel.

[0183] The display panel of the present embodiment and any of the above embodiments can be cross-referenced to each other and will not be described in detail herein. For example, the specific configuration of the first hole-type host material, the second electron-type host material and the third host material can be found in the above text.

[0184] like Figures 1 to 4 As shown, an embodiment of the first aspect of the present application also provides a display panel, comprising: a substrate 100; a light-emitting unit 200, which is arranged on one side of the substrate 100, the light-emitting unit 200 includes a red light-emitting unit, a green light-emitting unit and a blue light-emitting unit, and the light-emitting unit 200 includes a light-emitting layer 210; wherein the light-emitting layer 210 includes a host material and a guest material, and the host material of at least one of the red light-emitting unit, the green light-emitting unit and the blue light-emitting unit includes a first hole-type host material and a second electron-type host material, and the mass ratio of the first hole-type host material to the second electron-type host material is 2:8 to 8:2.

[0185] In the embodiment of the present application, for example, the mass ratio of the first hole-type host material to the second electron-type host material is 2:8, 3:7, 4:6, 5:5, 6:4, 8:2, etc. When the mass ratio of the first hole-type host material to the second electron-type host material is within the above range, it can improve the situation that one of the first hole-type host material and the second electron-type host material has too much mass and the other has too little mass, which affects the injection and transmission of electrons or holes in the host material.

[0186] Optionally, the mass ratio of the first hole-type host material to the second electron-type host material is 4:6 to 6:4. For example, the mass ratio of the first hole-type host material to the second electron-type host material is 4:6, 4.5:5.5, 5:5, 5.5:4.5, 6:4, etc. The mass ratio of the first hole-type host material to the second electron-type host material is within a suitable range to ensure the transmission and injection of holes or electrons.

[0187] In order to further illustrate the improvement of the present application, Example 1 and Comparative Example 1 are used as examples below, wherein Comparative Example 1 provides a light-emitting device, the light-emitting layer of the light-emitting device includes a host material and a guest material, and the host material is a single host material. Example 1 provides a light-emitting device, the light-emitting layer of the light-emitting device includes a host material and a guest material, and the host material includes a first hole-type host material and a second electron-type host material. The specific materials of Example 1 and Comparative Example 1 are selected from the materials described above, the difference being that Example 1 is a dual host material, Comparative Example 1 is a single host material, and the dipole moments of the host materials of Example 1 and Comparative Example 1 are different. The luminescent effects of the two embodiments were measured to obtain the following results:

[0188] Spectral peak Half peak width Dipole moment Comparative Example 1 624 35 1.88 Example 1 621 33 0.98

[0189] Please also read Figure 5 and Figure 6 It can be seen that the dipole moment of Example 1 is reduced compared with Comparative Example 1, and the spectral peak is reduced, which means that the color gamut of Example 1 is wider. The half-peak width of Example 1 is smaller, which means that the color purity of Example 1 is high, the energy is concentrated and emitted, and the device effect of Example 1 is higher.

[0190] Spectral peak Half peak width Dipole moment Comparative Example 2 623 34 1.10 Example 2 622 33 0.93

[0191] To further illustrate the beneficial effects of the embodiments of the present application, Comparative Example 2 and Example 2 are provided, wherein Comparative Example 2 provides a light-emitting device, the light-emitting layer of which includes a first hole-type host material, a second electron-type host material and a guest material, and the host material is a dual host material. Example 2 provides a light-emitting device, the light-emitting layer of which includes a host material and a guest material, and the host material includes a first hole-type host material and a second electron-type host material, and the host material is also a dual host material. The materials in Comparative Example 2 and Example 2 are the same, except that the mixing ratio of the first hole-type host material and the second electron-type host material is 8:2 in Comparative Example 2, and 6:4 in Example 2. From the above experimental data and Figure 7 It can be seen that when the host materials of Example 2 and Comparative Example 2 are both mixed hosts, different mixing ratios cause the dipole moment to change, and further cause the peak value and half-peak width of the guest emission spectrum to change.

[0192] Spectral peak Half peak width Dipole moment Comparative Example 3 625 35 1.25 Example 3 624 35 1.16

[0193] To further illustrate the beneficial effects of the embodiments of the present application, Comparative Example 3 and Example 3 are provided, wherein Comparative Example 3 provides a light-emitting device, the light-emitting layer of the light-emitting device includes a first hole-type host material, a second electron-type host material and a guest material, and the host material is a dual host material. Example 3 provides a light-emitting device, the light-emitting layer of the light-emitting device includes a host material and a guest material, and the host material includes a first hole-type host material, a second electron-type host material and a third host material, and the host material is a triple host material. The materials in Comparative Example 3 and Example 3 are the same, except that a third host material is added to the host material of Example 3. It can be seen from the above data analysis that the addition of the third host material has an adjustment and optimization effect on the spectral peak, and does not change the half-peak width.

[0194] It can be seen from the above comparative example experiments that when the dipole moment of the host material changes, the spectral characteristics of the light-emitting device will change.

[0195] The display panel of the present application embodiment and any of the above embodiments can be cross-referenced to each other and will not be described in detail herein. For example, the specific configuration of the first hole-type host material and the second electron-type host material can be found in the above text.

[0196] The embodiment of the second aspect of the present application also provides a display device, including the display panel of any of the above-mentioned embodiments of the first aspect. Since the display device provided by the embodiment of the second aspect of the present application includes the display panel of any of the above-mentioned embodiments of the first aspect, the display device provided by the embodiment of the second aspect of the present application has the beneficial effects of the display panel of any of the above-mentioned embodiments of the first aspect, which will not be repeated here.

[0197] The display device in the embodiments of the present application includes but is not limited to mobile phones, personal digital assistants (PDAs), tablet computers, e-books, televisions, access control systems, smart landline phones, consoles, and other devices with display functions.

[0198] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present application. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A display panel, characterized in that: include: substrate; A light-emitting unit is disposed on one side of the substrate, and the light-emitting unit includes a light-emitting layer; The light-emitting layer includes a host material and a guest material, and the dipole moment of the host material of the light-emitting layer of at least one of the light-emitting units is 0.2D to 5.0D.

2. The display panel according to claim 1, characterized in that: The host material of at least one of the light-emitting units includes a first hole-type host material and a second electron-type host material, and the dipole moment of the host material is 0.3D to 4.0D; Preferably, the LUMO energy level of the first hole-type host material is higher than the LUMO energy level of the second electron-type host material; Preferably, the HOMO energy level of the first hole-type host material is higher than the HOMO energy level of the second electron-type host material.

3. The display panel according to claim 2, characterized in that: In the host material of the same light-emitting unit, the mass ratio of the first hole-type host material to the second electron-type host material is 2:8 to 8:2; Preferably, in the host material of the same light-emitting unit, the mass ratio of the first hole-type host material to the second electron-type host material is 4:6 to 6:

4.

4. The display panel according to claim 2, characterized in that: The host material of at least one of the light-emitting units further includes a third host material, the molecular polarity of the third host material is greater than or less than the molecular polarity of the first hole-type host material, and / or the molecular polarity of the third host material is greater than or less than the molecular polarity of the second electron-type host material; Preferably, the molecular polarity of the third host material is greater than the molecular polarity of the first hole-type host material and the second electron-type host material, or the molecular polarity of the third host material is less than the molecular polarity of the first hole-type host material and the second electron-type host material; Preferably, the LUMO energy level of the third host material is higher than the LUMO energy level of the first hole-type host material; Preferably, the HOMO energy level of the third host material is higher than the HOMO energy level of the first hole-type host material.

5. The display panel according to claim 4, characterized in that: The first hole-type host material and the second electron-type host material form an exciplex, and the T1 state energy level of the third host material is higher than the T1 state energy level of the exciplex; Preferably, the T1 state energy level of the third host material is higher than the T1 state energy level of the guest material.

6. The display panel according to claim 4, characterized in that: The first hole-type host material and the second electron-type host material form an exciplex, and the S1 state energy level of the third host material is higher than the S1 state energy level of the exciplex; Preferably, the S1 state energy level of the third host material is higher than the S1 state energy level of the guest material; Preferably, the light-emitting unit includes a red light-emitting unit, a green light-emitting unit and a blue light-emitting unit, the main material of the red light-emitting unit includes the third main material, and the S1 state energy level of the third main material of the red light-emitting unit is greater than 2.60 eV; and / or, The host material of the green light-emitting unit includes the third host material, and the S1 state energy level of the third host material of the green light-emitting unit is greater than 3.1 eV; and / or, The host material of the blue light-emitting unit includes the third host material, and an S1 state energy level of the third host material of the blue light-emitting unit is greater than 3.1 eV.

7. The display panel according to claim 4, characterized in that: The third host material includes a polar compound or a non-polar compound; Preferably, the third host material comprises a polar compound, and the polar compound comprises an aromatic compound; Preferably, the aromatic compound included in the third host material includes a donor group and an acceptor group; Preferably, the donor group includes at least one of carbazolyl, arylamino, dibenzofuran, dibenzothiophene, naphthyl, phenanthryl, pyridyl, alkyl, alkoxy, and biphenyl; Preferably, the acceptor group comprises at least one of diazines and triazines; Preferably, the diazine comprises at least one of pyridazine, pyrimidine and pyrazine; Preferably, the third main material comprises a non-polar compound, and the non-polar compound comprises an aromatic ring compound; Preferably, the aromatic ring compound includes at least one of spirofluorene, biphenyl and carbazole.

8. The display panel according to claim 4, characterized in that: The light-emitting layer comprises a first sublayer, a second sublayer and a third sublayer stacked in a direction away from the substrate, and the doping concentration of the third host material of the first sublayer and / or the third sublayer is less than the doping concentration of the third host material of the second sublayer; Preferably, the doping concentration of the third main material of the first sub-layer and / or the third sub-layer is 0; Preferably, the first sublayer includes a first surface facing away from the second sublayer, the second sublayer includes a second surface facing the first sublayer and a third surface facing the third sublayer, the third sublayer includes a fourth surface facing away from the second sublayer, and the distance between the first surface and the second surface is smaller than the distance between the third surface and the fourth surface; Preferably, the light-emitting unit further includes a first electrode and a second electrode, the first electrode is located on a side of the light-emitting layer facing the substrate, the second electrode is located on a side of the light-emitting layer away from the substrate, the first electrode is an anode, and the second electrode is a cathode.

9. The display panel according to claim 4, characterized in that: The mass of the third host material accounts for 0.5% to 10% of the total mass of the light-emitting layer; Preferably, the mass of the third host material accounts for 1% to 5% of the total mass of the light-emitting layer.

10. The display panel according to claim 2, characterized in that: The dipole moment of the first hole-type host material is 1.2D to 4.0D, and / or the dipole moment of the second electron-type host material is 0.3D to 2.5D.

11. The display panel according to claim 10, characterized in that: The light-emitting unit includes a red light-emitting unit, the red light-emitting unit includes the first hole-type host material and the second electron-type host material, the dipole moment of the first hole-type host material of the red light-emitting unit is 1.2D to 3.0D, and / or the dipole moment of the second electron-type host material of the red light-emitting unit is 0.4D to 1.2D; Preferably, the dipole moment of the first hole-type host material of the red light-emitting unit is 1.2D to 1.7D, and / or the dipole moment of the second electron-type host material of the red light-emitting unit is 0.4D to 1.0D; Preferably, the first hole-type host material of the red light-emitting unit includes at least one of carbazole, dibenzofuran, and a derivative of carbazole and dibenzofuran connected by a single bond or a benzene ring; Preferably, the second electronic host material of the red light-emitting unit includes polysubstituted triazines, dibenzothiophene, and derivatives of polysubstituted triazines and dibenzothiophene connected by single bonds or benzene rings; Preferably, the first hole-type host material and the second electron-type host material of the red light-emitting unit form a first exciplex, the S1 state energy level of the first exciplex is 2.45eV to 2.60eV, and / or the T1 state energy level of the first exciplex is 2.30eV to 2.40eV.

12. The display panel according to claim 11, characterized in that: The HOMO energy level of the first hole-type host material of the red light-emitting unit is -5.40 eV to -5.10 eV; and / or the LUMO energy level of the second electron-type host material of the red light-emitting unit is -3.10 eV to -2.60 eV; Preferably, the HOMO energy level of the first hole-type host material of the red light-emitting unit is -5.30 eV to -5.20 eV; and / or the LUMO energy level of the second electron-type host material of the red light-emitting unit is -3.00 eV to -2.70 eV.

13. The display panel according to claim 10, characterized in that: The light-emitting unit includes a green light-emitting unit, and the green light-emitting unit includes the first hole-type host material and the second electron-type host material, the dipole moment of the first hole-type host material of the green light-emitting unit is 2.0D to 4.0D, and / or the dipole moment of the second electron-type host material of the green light-emitting unit is 0.3D to 2.5D; Preferably, the dipole moment of the first hole-type host material of the green light-emitting unit is 2.9D to 3.2D, and / or the dipole moment of the second electron-type host material of the green light-emitting unit is 1.5D to 1.8D; Preferably, the first hole-type host material of the green light-emitting unit includes a bicarbazole compound; Preferably, the first hole-type host material of the green light-emitting unit includes at least one of a dicarbazole and an N-carbazole compound, where N is a positive integer greater than or equal to 3; Preferably, the second electronic type host material of the green light-emitting unit includes triphenylene or a multi-substituted triazine derivative; Preferably, the first hole-type host material and the second electron-type host material of the green light-emitting unit form a second exciplex, the S1 state energy level of the second exciplex is 2.85eV to 3.10eV, and / or the T1 state energy level of the second exciplex is 2.60eV to 2.80eV.

14. The display panel according to claim 13, characterized in that: The HOMO energy level of the first hole-type host material of the green light-emitting unit is -5.50 eV to -5.20 eV; and / or the LUMO energy level of the second electron-type host material of the green light-emitting unit is -2.90 eV to -2.20 eV; Preferably, the HOMO energy level of the first hole-type host material of the green light-emitting unit is -5.40 eV to -5.30 eV; and / or the LUMO energy level of the second electron-type host material of the green light-emitting unit is -2.80 eV to -2.30 eV.

15. The display panel according to claim 10, characterized in that: The light-emitting unit includes a blue light-emitting unit, the blue light-emitting unit includes the first hole-type host material and the second electron-type host material, the dipole moment of the first hole-type host material of the blue light-emitting unit is 1.5D to 3.5D, and / or the dipole moment of the second electron-type host material of the blue light-emitting unit is 0.5D to 2.5D; Preferably, the dipole moment of the first hole-type host material of the blue light-emitting unit is 2.0D to 3.0D, and / or the dipole moment of the second electron-type host material of the blue light-emitting unit is 0.7D to 1.5D; Preferably, the first hole-type host material of the blue light-emitting unit includes: at least one of biphenyl or dibenzofuran derivatives, carbazole or triphenylphosphine derivatives; Preferably, the second electronic type host material of the blue light-emitting unit includes: at least one of pyridine, triazine, benzimidazole compound, and nitrogen-containing heterocyclic compound; Preferably, the first hole-type host material and the second electron-type host material of the blue light-emitting unit form a mixture, the S1 state energy level of the mixture is 3.00 eV to 3.10 eV, and / or the T1 state energy level of the mixture is 2.80 eV to 3.00 eV.

16. The display panel according to claim 15, characterized in that: The HOMO energy level of the first hole-type host material of the blue light-emitting unit is -5.90 eV to -5.40 eV; and / or the LUMO energy level of the second electron-type host material of the blue light-emitting unit is -3.00 eV to -2.70 eV; Preferably, the HOMO energy level of the first hole-type host material of the blue light-emitting unit is -5.80 eV to -5.50 eV; and / or the LUMO energy level of the second electron-type host material of the blue light-emitting unit is -3.00 eV to -2.80 eV.

17. The display panel according to claim 1, characterized in that: The host material of at least one of the light-emitting units is a single host material, and the dipole moment of the host material is 1.5D to 5.0D, or the dipole moment of the host material is 0.2D to 1.5D; Preferably, the dipole moment of the host material is 2.0D to 4.0D.

18. The display panel according to claim 1, characterized in that: The light-emitting units include a red light-emitting unit, a green light-emitting unit and a blue light-emitting unit, and the mass of the guest material of the red light-emitting unit accounts for 1% to 4% of the total mass of the light-emitting layer; and / or, the mass of the guest material of the green light-emitting unit accounts for 5% to 15% of the total mass of the light-emitting layer; and / or, the mass of the guest material of the blue light-emitting unit accounts for 1% to 5% of the total mass of the light-emitting layer; Preferably, the mass of the guest material of the red light-emitting unit accounts for 1.5% to 2.5% of the total mass of the light-emitting layer; and / or, the mass of the guest material of the green light-emitting unit accounts for 8% to 10% of the total mass of the light-emitting layer; And / or, the mass of the guest material of the blue light-emitting unit accounts for 1.5% to 2.5% of the total mass of the light-emitting layer.

19. The display panel according to claim 1, characterized in that: The light-emitting unit includes two or more light-emitting layers stacked in layers, and the dipole moment of the host material of at least one of the light-emitting layers of at least one of the light-emitting units is 0.2D to 5.0D.

20. A light emitting device, characterized in that: The light-emitting device comprises a light-emitting layer, wherein the light-emitting layer comprises a host material and a guest material, and the dipole moment of the host material is 0.2D to 5.0D.

21. A display panel, characterized in that: include: substrate; A light-emitting unit is disposed on one side of the substrate, the light-emitting unit includes a red light-emitting unit, a green light-emitting unit and a blue light-emitting unit, and the light-emitting unit includes a light-emitting layer; Among them, the light-emitting layer includes a host material and a guest material, and the host material of at least one of the red light-emitting unit, the green light-emitting unit and the blue light-emitting unit includes a first hole-type host material and a second electron-type host material, and the mass ratio of the first hole-type host material to the second electron-type host material is 2:8 to 8:

2.

22. A display device, characterized in that: Comprising a display panel as described in any one of claims 1-18 or claim 21.

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