White organic electroluminescent device and display device

Abstract

The invention discloses a white organic light-emitting device and a display device, the white organic light-emitting device comprises a first electrode, a second electrode and a light-emitting layer located between the first electrode and the second electrode, the light-emitting layer comprises a green light-emitting layer, a blue light-emitting layer and a plurality of red light-emitting layers which are distributed in a stacked mode, the red light-emitting layer is in contact with the green light-emitting layer; along the direction close to the green light-emitting layer, the hole mobility of the red light-emitting layers is gradually reduced, and the electron mobility of the red light-emitting layers is gradually enhanced. The white organic light-emitting device provided by the embodiment of the invention can effectively improve the color cast problem under high current density.

Description

Technical Field

[0001] The embodiments of the present application relate to but are not limited to the field of display technology, and in particular to a white organic electroluminescent device and a display apparatus. Background Art

[0002] Organic light emitting devices (OLED) are light emitting diodes based on organic semiconductor materials. OLEDs can be used as display devices and have good application prospects in the field of lighting due to their many advantages such as full solid state, active light emission, high contrast, ultra-thin, low power consumption, no viewing angle limitation, fast response speed, wide operating temperature range, easy to achieve flexibility and large area, and low power consumption. In order to achieve full color of OLED displays, one way is to use a side-by-side structure in which red, green and blue (RGB) sub-pixels emit light separately, and another way is to use a tandem structure (tandem WOLED+CF) in which a white organic light emitting diode (WOLED) and a color filter (CF) layer are superimposed. In WOLED, two or more light emitting layers are connected through a charge generation layer (CGL) to emit white light, and RGB monochromatic light is obtained after filtering by the CF layer. Because the light emitting layers are superimposed, it is called a tandem structure. Since the superposition structure of WOLED and CF layers does not require precise masking process, the high resolution of OLED display can be achieved. Therefore, although small and medium-sized OLED display panels generally adopt the parallel structure of RGB pixels, large-sized OLED display panels generally adopt the superposition structure of WOLED and CF layers. It can be seen that white light OLED devices have become one of the important ways to make large-sized display panels and lighting devices. At present, white light OLED devices mostly use three-layer emitting layers (red light R + green light G + blue light B, or blue light B + yellow light Y + blue light B, or blue light B + yellow light Y + yellow light Y), or double-layer emitting layers (blue light B + yellow light Y) to produce white light.

[0003] Currently, the color shift of mass-produced WOLED devices under high current density is usually more obvious. This is because the exciton recombination center is at the interface of the red and green light-emitting layers. As the current increases, the recombination center moves to the green light-emitting layer, resulting in a significant increase in green light efficiency under high current density, thus causing color shift. Summary of the invention

[0004] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of protection of this application.

[0005] The embodiments of the present application provide a white organic electroluminescent device (WOLED) and a display device. The white organic electroluminescent device can effectively improve the color shift problem under high current density.

[0006] The embodiment of the present application provides a white organic electroluminescent device, the white organic electroluminescent device comprising: a first electrode, a second electrode, and a light-emitting layer located between the first electrode and the second electrode, the light-emitting layer comprising a stacked green light-emitting layer, a blue light-emitting layer, and a plurality of red light-emitting layers, the red light-emitting layer being in contact with the green light-emitting layer;

[0007] Along the direction approaching the green light-emitting layer, the hole mobility of the plurality of red light-emitting layers gradually decreases and the electron mobility gradually increases.

[0008] In some embodiments of the present application, in any two adjacent red sub-light emitting layers, the one with higher hole mobility is the first red light emitting layer, and the one with higher electron mobility is the second red light emitting layer;

[0009] μh1≥100μh2; μe2≥100μe1;

[0010] Wherein, μh1 is the hole mobility of the first red light-emitting layer, and μh2 is the hole mobility of the second red light-emitting layer;

[0011] μe1 is the electron mobility of the first red light-emitting layer, and μe2 is the electron mobility of the second red light-emitting layer.

[0012] In some embodiments of the present application, μh1 is in the range of 100 μh2 to 500 μh2.

[0013] In some embodiments of the present application, μe2 is in the range of 100 μe1 to 500 μe1.

[0014] In some embodiments of the present application, μh1 is 10 -5 Order of magnitude, μh2 in 10 -7 Order of magnitude;

[0015] μe2 in 10 -5 Order of magnitude, μe1 in 10 -7 Order of magnitude.

[0016] In some embodiments of the present application, the red light-emitting layer includes a P-type red light-emitting material and an N-type red light-emitting material;

[0017] In the first red light-emitting layer, the content ratio of the P-type red light-emitting material to the N-type red light-emitting material is in the range of (1 to 3):1;

[0018] In the second red light-emitting layer, a content ratio of the N-type red light-emitting material to the P-type red light-emitting material is in the range of (1 to 3):1.

[0019] In some embodiments of the present application, the red light-emitting layer includes a host material and a guest material;

[0020] In some embodiments of the present application, the triplet energy level of the host material is higher than the triplet energy level of the guest material.

[0021] In some embodiments of the present application, the difference between the triplet energy levels of the host material and the guest material is not less than 0.3 eV.

[0022] In some embodiments of the present application, the red light-emitting layer includes at least two guest materials.

[0023] In some embodiments of the present application, the green light-emitting layer, the blue light-emitting layer and the plurality of red light-emitting layers are located in the same light-emitting unit; or,

[0024] The green light-emitting layer and the multiple red light-emitting layers are located in the same light-emitting unit; the blue light-emitting layer is located in another different light-emitting unit; and the different light-emitting units are connected via a charge generation layer.

[0025] In some embodiments of the present application, any one or more of a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer and an electron injection layer are also included.

[0026] In some embodiments of the present application, the red light-emitting layer includes a red host material and a red guest material, the red host material includes any one or more of a carbazole fused ring red light-emitting material, a chain carbazole red light-emitting material and a phenanthroline oxazole red light-emitting material; the red guest material includes any one or more of a complex of Ir and a quinoline aromatic compound and a complex of Ir and a β-diketone compound.

[0027] The green light-emitting layer includes a green host material and a green guest material; the green host material includes any one or more of coumarin dyes, triazine green light-emitting materials, quinacridone copper derivative green light-emitting materials, polycyclic aromatic hydrocarbon green light-emitting materials, diamine anthracene derivative green light-emitting materials and carbazole derivative green light-emitting materials, and the green guest material includes any one or more of metal complex green light-emitting materials.

[0028] In some embodiments of the present application, the blue light-emitting layer includes a blue host material and a blue guest material; the blue host material includes any one or more of pyrene derivative blue light-emitting materials, anthracene derivative blue light-emitting materials, fluorene derivative blue light-emitting materials, perylene derivative blue light-emitting materials and styrylamine derivative blue light-emitting materials, and the blue guest material includes any one or more of metal complex blue light-emitting materials.

[0029] In some embodiments of the present application, the material of the hole injection layer includes a transition metal oxide; or, the material of the hole injection layer includes a hole transport material and a p-type dopant;

[0030] The transition metal oxide includes any one or more of molybdenum oxide, titanium oxide, vanadium oxide, rhenium oxide, ruthenium oxide, chromium oxide, zirconium oxide, hafnium oxide, tantalum oxide, silver oxide, tungsten oxide, and manganese oxide;

[0031] The p-type dopant includes any one or more of 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene, 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyano-p-benzoquinone, and 1,2,3-tris[(cyano)(4-cyano-2,3,5,6-tetrafluorophenyl)methylene]cyclopropane;

[0032] The hole transport material includes any one or more of an aromatic amine hole transport material, a dimethylfluorene hole transport material, and a carbazole hole transport material.

[0033] In some embodiments of the present application, the material of the hole transport layer includes any one or more of aromatic amine hole transport materials, dimethylfluorene hole transport materials, and carbazole hole transport materials.

[0034] In some embodiments of the present application, the material of the electron blocking layer includes any one or more of aromatic amine electron blocking materials, dimethylfluorene electron blocking materials, and carbazole electron blocking materials.

[0035] In some embodiments of the present application, the material of the hole blocking layer includes any one or more of benzimidazole derivative hole blocking materials, imidazopyridine derivative hole blocking materials, benzimidazolephenanthridine derivative hole blocking materials, pyrimidine derivative hole blocking materials, triazine derivative hole blocking materials, quinoline derivative hole blocking materials, isoquinoline derivative hole blocking materials, and phenanthroline derivative hole blocking materials.

[0036] In some embodiments of the present application, the material of the electron transport layer includes any one or more of benzimidazole derivative electron transport materials, imidazopyridine derivative electron transport materials, benzimidazolephenanthridine derivative electron transport materials, pyrimidine derivative electron transport materials, triazine derivative electron transport materials, quinoline derivative electron transport materials, isoquinoline derivative electron transport materials, and phenanthroline derivative electron transport materials.

[0037] In some embodiments of the present application, the material of the electron injection layer includes any one or more of an alkali metal electron injection material and a metal electron injection material.

[0038] An embodiment of the present application further provides a display device, which includes the white organic electroluminescent device as described above.

[0039] The white organic electroluminescent device (WOLED) of the embodiment of the present application is designed with multiple red light-emitting layers with different hole and electron transmission capabilities, so that the transmission of electrons and holes in the light-emitting layer is more balanced, and the exciton recombination center of the device moves to the interface between two adjacent red light-emitting layers, so that the color deviation problem of the WOLED device of the embodiment of the present application under high current density is effectively improved.

[0040] Other features and advantages of the present application will be described in the following description, and partly become clearer from the description, or understood by practicing the present application. Other advantages of the present application can be realized and obtained by the schemes described in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0042] Figure 1 A schematic structural diagram of a white organic electroluminescent device according to an exemplary embodiment of the present application;

[0043] Figure 2 A schematic structural diagram of another white organic electroluminescent device according to an exemplary embodiment of the present application;

[0044] Figure 3 RGB spectrum curves of the white organic electroluminescent device at different voltages in Example 1 of the present application;

[0045] Figure 4 The RGB spectrum curves of the white organic electroluminescent device of the comparative example of the present application at different voltages. DETAILED DESCRIPTION

[0046] The present application describes multiple embodiments, but the description is exemplary rather than restrictive, and it is obvious to those skilled in the art that there may be more embodiments and implementations within the scope of the embodiments described in the present application. Although many possible feature combinations are shown in the drawings and discussed in the specific embodiments, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with any other feature or element in any other embodiment, or may replace any other feature or element in any other embodiment.

[0047] The present application includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The embodiments, features and elements disclosed in the present application may also be combined with any conventional features or elements to form a unique invention scheme. Any features or elements of any embodiment may also be combined with features or elements from other invention schemes to form another unique invention scheme. Therefore, it should be understood that any feature shown and / or discussed in the present application may be implemented individually or in any appropriate combination. Therefore, except for the limitations made according to the attached claims and their equivalents, the embodiments are not subject to other restrictions. In addition, various modifications and changes may be made within the scope of protection of the attached claims.

[0048] In addition, when describing representative embodiments, the specification may have presented the method and / or process as a specific sequence of steps. However, to the extent that the method or process does not rely on the specific order of the steps described herein, the method or process should not be limited to the steps of the specific order described. As will be understood by those of ordinary skill in the art, other sequences of steps are also possible. Therefore, the specific sequence of the steps set forth in the specification should not be interpreted as a limitation to the claims. In addition, the claims for the method and / or process should not be limited to the steps of performing them in the order written, and those skilled in the art can easily understand that these sequences can be changed and still remain within the spirit and scope of the embodiments of the present application.

[0049] The embodiments of the present application are not necessarily limited to the dimensions shown in the drawings. The shapes and sizes of the components in the drawings belong to the preferred embodiments and may also be other shapes and sizes. In addition, the drawings schematically show ideal examples, and the embodiments of the present application are not limited to the shapes or values ​​shown in the drawings.

[0050] The size and proportion relationship between the various film layers or components in the drawings of this application can be used as a reference in the actual process, which is an implementation method with good technical effects, but is not limited to this. For example, the width-to-length ratio of the light-emitting layer, the thickness and spacing of each film layer can be adjusted according to actual needs.

[0051] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0052] In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include at least one of the features.

[0053] In the description of the present application, “plurality” means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0054] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0055] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0056] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0057] In the present application, "film" and "layer" can be interchanged. For example, "luminescent layer" can sometimes be replaced by "luminescent film".

[0058] The embodiment of the present application provides a white organic electroluminescent device, the white organic electroluminescent device comprising: a first electrode, a second electrode, and a light-emitting layer located between the first electrode and the second electrode, the light-emitting layer comprising a stacked green light-emitting layer, a blue light-emitting layer, and a plurality of red light-emitting layers, the red light-emitting layer being in contact with the green light-emitting layer;

[0059] Along the direction approaching the green light-emitting layer, the hole mobility of the plurality of red light-emitting layers gradually decreases and the electron mobility gradually increases.

[0060] The white organic electroluminescent device (WOLED) of the embodiment of the present application is designed with multiple red light-emitting layers with different hole and electron transmission capabilities, so that the transmission of electrons and holes in the light-emitting layer is more balanced, and the exciton recombination center of the device moves to the interface between two adjacent red light-emitting layers, so that the color deviation problem of the WOLED device of the embodiment of the present application under high current density is effectively improved.

[0061] In some embodiments of the present application, in any two adjacent red sub-light emitting layers, the one with higher hole mobility is the first red light emitting layer, and the one with higher electron mobility is the second red light emitting layer;

[0062] μh1≥100μh2; μe2≥100μe1;

[0063] Wherein, μh1 is the hole mobility of the first red light-emitting layer, and μh2 is the hole mobility of the second red light-emitting layer;

[0064] μe1 is the electron mobility of the first red light-emitting layer, and μe2 is the electron mobility of the second red light-emitting layer.

[0065] When μh1≥100μh2 and μe2≥100μe1, it is beneficial to improve the carrier transport balance inside the WOLED device and adjust the exciton recombination center of the device to move to the interface between two adjacent red light-emitting layers.

[0066] In some embodiments of the present application, μh1 is in the range of 100 μh2 to 500 μh2. For example, μh1 may be 100 μh2, 150 μh2, 200 μh2, 250 μh2, 300 μh2, 350 μh2, 400 μh2, 450 μh2 or 500 μh2.

[0067] In some embodiments of the present application, μe2 is in the range of 100 μe1 to 500 μe1. For example, μe2 may be 100 μe1, 150 μe1, 200 μe1, 250 μe1, 300 μe1, 350 μe1, 400 μe1, 450 μe1 or 500 μe1.

[0068] In some embodiments of the present application, μh1 is 10 -5 Order of magnitude, μh2 in 10 -7 Order of magnitude;

[0069] μe2 in 10 -5 Order of magnitude, μe1 in 10 -7 Order of magnitude.

[0070] In some embodiments of the present application, the red light-emitting layer includes a P-type red light-emitting material and an N-type red light-emitting material;

[0071] In the first red light-emitting layer, the content ratio of the P-type red light-emitting material to the N-type red light-emitting material is in the range of (1 to 3):1;

[0072] In the second red light-emitting layer, a content ratio of the N-type red light-emitting material to the P-type red light-emitting material is in the range of (1 to 3):1.

[0073] When the content ratio of the P-type red light-emitting material to the N-type red light-emitting material in the first red light-emitting layer is in the range of (1 to 3):1, and the content ratio of the N-type red light-emitting material to the P-type red light-emitting material in the second red light-emitting layer is in the range of (1 to 3):1, it is beneficial to improve the carrier transport balance inside the WOLED device and adjust the exciton recombination center of the device to move to the interface between two adjacent red light-emitting layers.

[0074] For example, in the first red light-emitting layer, the content ratio of the P-type red light-emitting material to the N-type red light-emitting material is 1:1, 1.5:1, 2:1, 2.5:1 or 3:1.

[0075] For another example, in the first red light-emitting layer, the content ratio of the P-type red light-emitting material to the N-type red light-emitting material is 1:1, 6:4 or 7:3.

[0076] For example, in the second red light-emitting layer, the content ratio of the N-type red light-emitting material to the P-type red light-emitting material is 1:1, 1.5:1, 2:1, 2.5:1 or 3:1.

[0077] For another example, in the second red light-emitting layer, the content ratio of the N-type red light-emitting material to the P-type red light-emitting material is 1:1, 6:4 or 7:3.

[0078] In some embodiments of the present application, the white organic electroluminescent device includes two red light-emitting layers, namely a first red light-emitting layer and a second red light-emitting layer.

[0079] In some embodiments of the present application, the red light-emitting layer includes a host material and a guest material;

[0080] In some embodiments of the present application, the triplet energy level of the host material is higher than the triplet energy level of the guest material.

[0081] In some embodiments of the present application, the difference between the triplet energy levels of the host material and the guest material is not less than 0.3 eV.

[0082] When the difference between the triplet energy levels of the host material and the guest material is not less than 0.3 eV, it is beneficial to improve the carrier transport balance inside the WOLED device and adjust the exciton recombination center of the device to move to the interface of two adjacent red light-emitting layers.

[0083] In some embodiments of the present application, the red light-emitting layer includes at least two guest materials.

[0084] In some embodiments of the present application, the green light-emitting layer, the blue light-emitting layer and the multiple red light-emitting layers are located in the same light-emitting unit. For example, the white organic electroluminescent device can be a single device, in which the green light-emitting layer, the blue light-emitting layer and the multiple red light-emitting layers are located in the same light-emitting unit, and the single device does not contain a charge generation layer, and the blue light-emitting layer and the other light-emitting layers can be connected through a connecting layer (interlayer).

[0085] In some embodiments of the present application, the green light-emitting layer and the multiple red light-emitting layers are located in the same light-emitting unit, and the blue light-emitting layer is located in another different light-emitting unit; the different light-emitting units are connected through a charge generation layer. For example, the white organic electroluminescent device can be a tandem device, and the tandem device includes two light-emitting units, wherein the green light-emitting layer and the multiple red light-emitting layers are located in one of the light-emitting units, and the blue light-emitting layer is located in the other light-emitting unit.

[0086] In some embodiments of the present application, the white organic electroluminescent device also includes any one or more of a hole injection layer (HIL), a hole transport layer (HTL), an electron blocking layer (EBL), a hole blocking layer (HBL), an electron transport layer (ETL) and an electron injection layer (EIL).

[0087] Figure 1 FIG. 1 is a schematic diagram of the structure of a white organic electroluminescent device according to an exemplary embodiment of the present application. Figure 1As shown, the white organic electroluminescent device can be a tandem device, and the tandem device can include a first electrode 10 located on one side of a substrate, a first hole injection layer (HIL) 21 located on the first electrode 10 and away from the substrate, a first hole transport layer (HTL) 31 located on the first hole injection layer 21 and away from the substrate, a first electron blocking layer (EBL) 41 located on the first hole transport layer 31 and away from the substrate, a blue light emitting layer (BEML) 51 located on the first electron blocking layer 41 and away from the substrate, a first hole blocking layer (HBL) 61 located on the blue light emitting layer 51 and away from the substrate, a first electron transport layer (ETL) 71 located on the first hole blocking layer 61 and away from the substrate, a charge generation layer (NCGL) 80 located on the first electron transport layer 71 and away from the substrate, and a first electrode 10 located on one side of the substrate. a second hole injection layer 22 of the charge generating layer 80 away from the substrate, a second hole transport layer 32 located at the second hole injection layer 22 away from the substrate, a second electron blocking layer 42 located at the second hole transport layer 32 away from the substrate, a first red light emitting layer 521 located at the second electron blocking layer 42 away from the substrate, a second red light emitting layer 522 located at the first red light emitting layer 521 away from the substrate, a green light emitting layer 53 located at the second red light emitting layer 522 away from the substrate, a second hole blocking layer 62 located at the green light emitting layer 53 away from the substrate, a second electron transport layer 72 located at the second hole blocking layer 62 away from the substrate, an electron injection layer (EIL) 90 located at the second electron transport layer 72 away from the substrate, and a second electrode 100 located at the electron injection layer 90 away from the substrate.

[0088] Figure 2 FIG. 1 is a schematic diagram of the structure of a white organic electroluminescent device according to an exemplary embodiment of the present application. Figure 1As shown, the white organic electroluminescent device can be a single device, and the single device can include a first electrode 10 located on one side of the substrate, a first hole injection layer (HIL) 21 located on the side of the first electrode 10 away from the substrate, a first hole transport layer (HTL) 31 located on the side of the first hole injection layer 21 away from the substrate, a first electron blocking layer (EBL) 41 located on the side of the first hole transport layer 31 away from the substrate, a first red light emitting layer 521 located on the side of the first electron blocking layer 41 away from the substrate, and a first red light emitting layer 521 located on the side of the first red light emitting layer 521 away from the substrate. a second red light-emitting layer 522 on one side, a green light-emitting layer 53 located on the second red light-emitting layer 522 on a side away from the substrate, a connecting layer 110 located on the green light-emitting layer 53 on a side away from the substrate, a blue light-emitting layer 51 located on the connecting layer 110 on a side away from the substrate, a first hole blocking layer 61 located on a side away from the substrate of the blue light-emitting layer 51, a first electron transport layer 71 located on a side away from the substrate of the first hole blocking layer 61, an electron injection layer 90 located on a side away from the substrate of the first electron transport layer 71, and a second electrode 100 located on a side away from the substrate of the electron injection layer 90.

[0089] The following uses tandem structure and single structure white organic electroluminescent devices as examples to illustrate the application of the technical solution of the present application in white organic electroluminescent devices.

[0090] This embodiment provides a WOLED device, and its manufacturing process includes:

[0091] First, make a TFT circuit on the silicon wafer, then lay a flat layer PLN, and further make an anode and a pixel definition layer PDL on the PLN. Then evaporate the OLED device. The evaporation order of the OLED device is: P-HTL (10nm) / HTL (100nm) / B-Prime (40nm) / BEML (20nm) / HBL (20nm) / ETL (30nm) / NCGL: Yb (18nm) / P-HTL (7nm) / HTL (12nm) / Prime (10nm) / REML-1 (10nm) / REML-2 (10nm) / GEML (30nm) / HBL (5nm) / ETL (30nm) / Yb (1nm) / Mg: Ag (1:9, 12nm). Then perform TFE packaging on the top in turn, followed by CVD1, IJP, and CVD2, to obtain the following Figure 1 The WOLED device shown in FIG. Among them, the P-HTL is formed of hole transport and P-type doping materials as HIL, and the B-Prime is formed of electron blocking materials and doping materials as EBL.

[0092] In this embodiment, the first red light-emitting layer REML-1 has only one host material, and the second red light-emitting layer REML-2 has only one host material.

[0093] This embodiment provides a WOLED device, and its manufacturing process includes:

[0094] First, make the TFT circuit on the silicon wafer, then lay a flat layer PLN, and further make the anode and pixel definition layer PDL on the PLN. Then evaporate the OLED device, the OLED device evaporation sequence is: P-HTL (10nm) / HTL (20nm) / Prime (10nm) / REML-1 (5nm) / REML-2 (5nm) / GEML (10nm) / interlayer (5nm) / B-EML (20nm) / HBL (5nm) / ETL (20nm) / Yb (1nm) / Mg: Ag (1:9, 12nm). Then perform TFE packaging on the top in turn, CVD1, IJP, CVD2, and get the following Figure 2 The WOLED device shown.

[0095] In this embodiment, the first red light-emitting layer REML-1 has only one host material, and the second red light-emitting layer REML-2 has only one host material.

[0096] This embodiment provides a WOLED device, and its manufacturing process includes:

[0097] First, make a TFT circuit on the silicon wafer, then lay a flat layer PLN, and further make an anode and a pixel definition layer PDL on the PLN. Then evaporate the OLED device. The evaporation sequence of the OLED device is: P-HTL (10nm) / HTL (100nm) / B-Prime (40nm) / BEML (20nm) / HBL (20nm) / ETL (30nm) / NCGL: Yb (18nm) / P-HTL (7nm) / HTL (12nm) / Prime (10nm) / REML-1 (10nm) / REML-2 (10nm) / GEML (30nm) / HBL (5nm) / ETL (30nm) / Yb (1nm) / Mg: Ag (1:9, 12nm). Then perform TFE packaging on the top in turn, followed by CVD1, IJP, and CVD2, to obtain the following Figure 1 The WOLED device shown in FIG. Among them, the P-HTL is formed of hole transport and P-type doping materials as HIL, and the B-Prime is formed of electron blocking materials and doping materials as EBL.

[0098] In this embodiment, the first red light emitting layer REML-1 and the second red light emitting layer REML-2 both have two types of host materials, namely a P-type host material and an N-type host material. The P / N ratio of REML-1 is greater than 1:1, and the P / N ratio of REML-2 is less than 1:1.

[0099] This embodiment provides a WOLED device, and its manufacturing process includes:

[0100] First, make the TFT circuit on the silicon wafer, then lay a flat layer PLN, and further make the anode and pixel definition layer PDL on the PLN. Then evaporate the OLED device, the OLED device evaporation sequence is: P-HTL (10nm) / HTL (20nm) / Prime (10nm) / REML-1 (5nm) / REML-2 (5nm) / GEML (10nm) / interlayer (5nm) / B-EML (20nm) / HBL (5nm) / ETL (20nm) / Yb (1nm) / Mg: Ag (1:9, 12nm). Then perform TFE packaging on the top in turn, CVD1, IJP, CVD2, and get the following Figure 2 The WOLED device shown.

[0101] In this embodiment, the first red light emitting layer REML-1 and the second red light emitting layer REML-2 both have two types of host materials, namely a P-type host material and an N-type host material. The P / N ratio of REML-1 is greater than 1:1, and the P / N ratio of REML-2 is less than 1:1.

[0102] In some embodiments of the present application, the first electrode may be an anode, and the first electrode may be formed of a material having a high work function. For example, for a bottom-emitting device, the anode may be made of a transparent oxide material, such as indium tin oxide (ITO) or indium zinc oxide (IZO). Alternatively, for a top-emitting device, the anode may be made of a composite structure of metal and transparent oxide, such as Ag / ITO (Indium Tin Oxide), Ag / IZO (Indium Zinc Oxide), Al / ITO, Al / IZO or ITO / Ag / ITO, etc., to ensure good reflectivity.

[0103] In some embodiments of the present application, the second electrode may be a cathode, and the second electrode may be formed of a metal with a lower work function such as Al, Ag, Mg, or an alloy containing a low work function metal material.

[0104] In some embodiments of the present application, the red light-emitting layer includes a red host material and a red guest material, the red host material includes any one or more of a carbazole fused ring red light-emitting material, a chain carbazole red light-emitting material and a phenanthroline oxazole red light-emitting material; the red guest material includes any one or more of a complex of Ir and a quinoline aromatic compound and a complex of Ir and a β-diketone compound.

[0105] For example, the red light emitting layer may include:

[0106]

[0107] Among them, RH-single is used to form a red host material alone, RH-P is used as a P-type red host material, RH-N is used as an N-type red host material, and RD is used as a red guest material.

[0108] In some embodiments of the present application, the green light-emitting layer includes a green host material and a green guest material; the green host material includes any one or more of coumarin dyes, triazine green light-emitting materials, quinacridone copper derivative green light-emitting materials, polycyclic aromatic hydrocarbon green light-emitting materials, diamine anthracene derivative green light-emitting materials and carbazole derivative green light-emitting materials, and the green guest material includes any one or more of metal complex green light-emitting materials.

[0109] For example, the green light-emitting material may include any one or more of coumarin 6 (C-6), coumarin 545T (C-525T), quinacridone copper (QA), N,N'-dimethylquinacridone (DMQA), 5,12-diphenylnaphthonaphthone (DPT), N10,N10'-diphenyl-N10,N10'-diphthaloyl-9,9'-dianthracene-10,10'-diamine (abbreviated as: BA-NPB), tris(8-hydroxyquinoline)aluminum(III) (abbreviated as: Alq3), tris(2-phenylpyridine)iridium (Ir(ppy)3), and di(2-phenylpyridine)iridium acetylacetonate (Ir(ppy)2(acac)).

[0110] For another example, the green light emitting layer may include:

[0111]

[0112] Among them, GH-P is used as a P-type green host material, GH-N is used as an N-type green host material, and GD is used as a green guest material.

[0113] In some embodiments of the present application, the blue light-emitting layer includes a blue host material and a blue guest material; the blue host material includes any one or more of pyrene derivative blue light-emitting materials, anthracene derivative blue light-emitting materials, fluorene derivative blue light-emitting materials, perylene derivative blue light-emitting materials and styrylamine derivative blue light-emitting materials, and the blue guest material includes any one or more of metal complex blue light-emitting materials and aromatic compounds containing boron and nitrogen.

[0114] For example, the blue light-emitting material may include any one or more of N1,N6-di([1,1'-biphenyl]-2-yl)-N1,N6-di([1,1'-biphenyl]-4-yl)pyrene-1,6-diamine, 9,10-di-(2-naphthyl)anthracene (ADN), 2-methyl-9,10-di-2-naphthylanthracene (MADN), 2,5,8,11-tetra-tert-butylperylene (TBPe), 4,4'-di[4-(diphenylamino)phenylvinyl]biphenyl (BDAV Bi), 4,4'-di[4-(di-p-tolylamino)phenylvinyl]biphenyl (DPAVBi), and bis(4,6-difluorophenylpyridine-C2,N)picolinyliridium (FIrpic).

[0115] For example, the blue guest material can be

[0116] In some embodiments of the present application, the material of the hole injection layer includes a transition metal oxide; or, the material of the hole injection layer includes a hole transport material and a p-type dopant;

[0117] The transition metal oxide includes any one or more of molybdenum oxide, titanium oxide, vanadium oxide, rhenium oxide, ruthenium oxide, chromium oxide, zirconium oxide, hafnium oxide, tantalum oxide, silver oxide, tungsten oxide, and manganese oxide;

[0118] The p-type dopant includes any one or more of 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene, 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyano-p-benzoquinone (F4TCNQ), and 1,2,3-tris[(cyano)(4-cyano-2,3,5,6-tetrafluorophenyl)methylene]cyclopropane;

[0119] The hole transport material includes any one or more of aromatic amine hole transport materials, dimethylfluorene hole transport materials, and carbazole hole transport materials.

[0120] In some embodiments of the present application, the material of the hole transport layer includes any one or more of aromatic amine hole transport materials, dimethylfluorene hole transport materials, and carbazole hole transport materials.

[0121] For example, the material of the hole transport layer may include any one or more of 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPB), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (TPD), 4-phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine (BAFLP), 4,4'-bis[N-(9,9-dimethylfluorene-2-yl)-N-phenylamino]biphenyl (DFLDPBi), 4,4'-di(9-carbazolyl)biphenyl (CBP) and 9-phenyl-3-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (PCzPA).

[0122] In some embodiments of the present application, the material of the electron blocking layer includes any one or more of aromatic amine electron blocking materials, dimethylfluorene electron blocking materials, and carbazole electron blocking materials.

[0123] For example, the material of the electron blocking layer may include any one or more of 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPB), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (TPD), 4-phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine (BAFLP), 4,4'-bis[N-(9,9-dimethylfluorene-2-yl)-N-phenylamino]biphenyl (DFLDPBi), 4,4'-di(9-carbazolyl)biphenyl (CBP) and 9-phenyl-3-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (PCzPA).

[0124] In some embodiments of the present application, the material of the hole blocking layer includes any one or more of benzimidazole derivative hole blocking materials, imidazopyridine derivative hole blocking materials, benzimidazolephenanthridine derivative hole blocking materials, pyrimidine derivative hole blocking materials, triazine derivative hole blocking materials, quinoline derivative hole blocking materials, isoquinoline derivative hole blocking materials, and phenanthroline derivative hole blocking materials.

[0125] In some embodiments of the present application, the material of the hole blocking layer may include any one or more of benzimidazole derivative hole blocking materials, imidazopyridine derivative hole blocking materials, benzimidazolephenanthridine derivative hole blocking materials, pyrimidine derivative hole blocking materials, triazine derivative hole blocking materials, quinoline derivative hole blocking materials, isoquinoline derivative hole blocking materials, and phenanthroline derivative hole blocking materials.

[0126] For example, the hole blocking layer material may include any one or more of 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (OXD-7), 3-(4-tert-butylphenyl)-4-phenyl-5-(4-biphenylyl)-1,2,4-triazole (TAZ), 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4-triazole (p-EtTAZ), bathophenanthroline (BPhen), bathocuproin (BCP), and 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (BzOs).

[0127] In some embodiments of the present application, the material of the electron transport layer includes any one or more of benzimidazole derivative electron transport materials, imidazopyridine derivative electron transport materials, benzimidazolephenanthridine derivative electron transport materials, pyrimidine derivative electron transport materials, triazine derivative electron transport materials, quinoline derivative electron transport materials, isoquinoline derivative electron transport materials, and phenanthroline derivative electron transport materials.

[0128] For example, the material of the electron transport layer may include any one or more of 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (OXD-7), 3-(4-tert-butylphenyl)-4-phenyl-5-(4-biphenyl)-1,2,4-triazole (TAZ), 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenyl)-1,2,4-triazole (p-EtTAZ), bathophenanthroline (BPhen), bathocuproine (BCP), and 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (BzOs).

[0129] In some embodiments of the present application, the material of the electron injection layer includes any one or more of an alkali metal electron injection material and a metal electron injection material.

[0130] For example, the electron injection layer material may include any one or more of LiF, Yb, Mg, and Ca.

[0131] In some embodiments of the present application, the material of the charge generation layer may include any one or more of phenanthroline compounds and terpyridine compounds.

[0132] For example, the material of the charge generation layer is

[0133] An embodiment of the present application further provides a display device, which includes the white organic electroluminescent device as described above.

[0134] In some embodiments of the present application, the display device can be any product or component with a display function, such as a mobile phone, a tablet computer, a television, a monitor, a laptop computer, a digital photo frame, a navigator, a car display, a smart watch, a smart bracelet, etc.

[0135] Figure 3 RGB spectrum curves of the white organic electroluminescent device at different voltages in Example 1 of the present application; Figure 4 RGB spectrum curves of the white organic electroluminescent device in the comparative example of the present application at different voltages. The white organic electroluminescent device in the comparative example is different from the white organic electroluminescent device in the comparative example of Example 1 only in that the white organic electroluminescent device in the comparative example of Example 1 includes a first red light-emitting layer and a second red light-emitting layer; the white organic electroluminescent device in the comparative example only includes the first red light-emitting layer.

[0136] By comparison Figure 3 and Figure 4 It can be seen that compared with the comparative example, the red light spectrum of the white organic electroluminescent device in Example 3 of the present application changes significantly less under different voltages, indicating that the design of the double-layer red light-emitting layer of the present application can effectively improve the color deviation problem of the WOLED device under high current density.

[0137] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A white organic electroluminescent device, characterized in that: include: A first electrode, a second electrode, and a light-emitting layer located between the first electrode and the second electrode, the light-emitting layer comprising a green light-emitting layer, a blue light-emitting layer, and a plurality of red light-emitting layers that are stacked and distributed, and the red light-emitting layer is in contact with the green light-emitting layer; Along the direction approaching the green light-emitting layer, the hole mobility of the plurality of red light-emitting layers gradually decreases and the electron mobility gradually increases.

2. The white organic electroluminescent device according to claim 1, characterized in that: In any two adjacent red sub-light emitting layers, the one with higher hole mobility is the first red light emitting layer, and the one with higher electron mobility is the second red light emitting layer; μh1≥100μh2; μe2≥100μe1; Wherein, μh1 is the hole mobility of the first red light-emitting layer, and μh2 is the hole mobility of the second red light-emitting layer; μe1 is the electron mobility of the first red light-emitting layer, and μe2 is the electron mobility of the second red light-emitting layer.

3. The white organic electroluminescent device according to claim 2, characterized in that: μh1 is in the range of 100μh2 to 500μh2.

4. The white organic electroluminescent device according to claim 2, characterized in that: μe2 is in the range of 100μe1 to 500μe1.

5. The white organic electroluminescent device according to claim 2, characterized in that: μh1 in 10 -5 Order of magnitude, μh2 in 10 -7 Order of magnitude; μe2 in 10 -5 Order of magnitude, μe1 in 10 -7 Order of magnitude.

6. The white organic electroluminescent device according to claim 2, characterized in that: The red light-emitting layer includes a P-type red light-emitting material and an N-type red light-emitting material; In the first red light-emitting layer, the content ratio of the P-type red light-emitting material to the N-type red light-emitting material is in the range of (1 to 3):1; In the second red light-emitting layer, a content ratio of the N-type red light-emitting material to the P-type red light-emitting material is in the range of (1 to 3):

1.

7. The white organic electroluminescent device according to claim 1, characterized in that: The red light-emitting layer comprises a host material and a guest material; The triplet energy level of the host material is higher than the triplet energy level of the guest material.

8. The white organic electroluminescent device according to claim 7, characterized in that: The difference between the triplet energy levels of the host material and the guest material is not less than 0.3 eV.

9. The white organic electroluminescent device according to claim 7, characterized in that: The red light emitting layer includes at least two guest materials.

10. The white organic electroluminescent device according to any one of claims 1 to 9, characterized in that: The green light-emitting layer, the blue light-emitting layer and the plurality of red light-emitting layers are located in the same light-emitting unit; or, The green light-emitting layer and the multiple red light-emitting layers are located in the same light-emitting unit; the blue light-emitting layer is located in another different light-emitting unit; and the different light-emitting units are connected via a charge generation layer.

11. The white organic electroluminescent device according to any one of claims 1 to 9, characterized in that: It also includes any one or more of a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer and an electron injection layer.

12. The white organic electroluminescent device according to claim 11, characterized in that: The red light-emitting layer includes a red host material and a red guest material, wherein the red host material includes any one or more of a carbazole condensed ring red light-emitting material, a chain carbazole red light-emitting material and a phenanthroline oxazole red light-emitting material; the red guest material includes any one or more of a complex of Ir and a quinoline aryl compound and a complex of Ir and a β-diketone compound; The green light-emitting layer includes a green main material and a green guest material; the green main material includes any one or more of coumarin dyes, triazine green light-emitting materials, quinacridone copper derivative green light-emitting materials, polycyclic aromatic hydrocarbon green light-emitting materials, diamine anthracene derivative green light-emitting materials and carbazole derivative green light-emitting materials, and the green guest material includes any one or more of metal complex green light-emitting materials; The blue light-emitting layer includes a blue host material and a blue guest material; the blue host material includes any one or more of pyrene derivative blue light-emitting materials, anthracene derivative blue light-emitting materials, fluorene derivative blue light-emitting materials, perylene derivative blue light-emitting materials and styrylamine derivative blue light-emitting materials, and the blue guest material includes any one or more of metal complex blue light-emitting materials.

13. The white organic electroluminescent device according to claim 11, characterized in that: The material of the hole injection layer includes a transition metal oxide; or the material of the hole injection layer includes a hole transport material and a p-type dopant; The transition metal oxide includes any one or more of molybdenum oxide, titanium oxide, vanadium oxide, rhenium oxide, ruthenium oxide, chromium oxide, zirconium oxide, hafnium oxide, tantalum oxide, silver oxide, tungsten oxide, and manganese oxide; The p-type dopant includes any one or more of 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene, 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyano-p-benzoquinone, and 1,2,3-tris[(cyano)(4-cyano-2,3,5,6-tetrafluorophenyl)methylene]cyclopropane; The hole transport material includes any one or more of an aromatic amine hole transport material, a dimethylfluorene hole transport material, and a carbazole hole transport material.

14. The white organic electroluminescent device according to claim 11, characterized in that: The material of the hole transport layer includes any one or more of aromatic amine hole transport materials, dimethylfluorene hole transport materials, and carbazole hole transport materials.

15. The white organic electroluminescent device according to claim 11, characterized in that: The material of the electron blocking layer includes any one or more of an aromatic amine electron blocking material, a dimethylfluorene electron blocking material, and a carbazole electron blocking material.

16. The white organic electroluminescent device according to claim 11, characterized in that: The material of the hole blocking layer includes any one or more of benzimidazole derivative hole blocking materials, imidazopyridine derivative hole blocking materials, benzimidazolephenanthridine derivative hole blocking materials, pyrimidine derivative hole blocking materials, triazine derivative hole blocking materials, quinoline derivative hole blocking materials, isoquinoline derivative hole blocking materials, and phenanthroline derivative hole blocking materials.

17. The white organic electroluminescent device according to claim 11, wherein the material of the electron transport layer comprises any one or more of benzimidazole derivative electron transport materials, imidazopyridine derivative electron transport materials, benzimidazolephenanthridine derivative electron transport materials, pyrimidine derivative electron transport materials, triazine derivative electron transport materials, quinoline derivative electron transport materials, isoquinoline derivative electron transport materials, and phenanthroline derivative electron transport materials.

18. The white organic electroluminescent device according to claim 11, characterized in that: The material of the electron injection layer includes any one or more of an alkali metal electron injection material and a metal electron injection material.

19. A display device, characterized in that: The invention comprises a white organic electroluminescent device according to any one of claims 1 to 18.

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