Stacked OLED device

Abstract

Disclosed in the present invention is a stacked OLED device, comprising an anode layer, one side thereof being successively provided with a first light-emitting layer, a charge generation layer and a second light-emitting layer in a direction away from the anode layer; an electron generation layer, a first hole generation layer and a second hole generation layer are successively provided in the charge generation layer in a direction away from the anode layer; and the charge generation layer is doped with an organic material having a strong electron absorption capability, and a doping ratio of the first hole generation layer is higher than that of the second hole generation layer. The stacked OLED device of the present invention divides the charge generation layer into a plurality of thinner layers, and adjusting the thicknesses and doping ratios of the layers inside the charge generation layer enables carrier rates of adjacent layers to be matched, which avoids an obvious voltage drop at an interface between two adjacent layers caused by charge accumulation, thereby prolonging the service life of OLED devices. No metal stabilizing layer is provided in the charge generation layer, which avoids the obstruction of light extraction due to low transmittance in visible light bands, thereby improving the efficiency of OLED devices.

Description

Stacked OLED device TECHNICAL FIELD

[0001] The present application relates to the field of OLED devices, in particular to a stacked OLED device. BACKGROUND

[0002] OLED devices have been widely used in high-performance display fields in recent years, and the demand for OLED devices is growing, especially for notebook computers and vehicle screens. Long life and high HDR are required for OLED screens, and therefore tandem OLED devices are increasingly favored by the market.

[0003] The key technology of the tandem device structure is the charge generation layer (CGL), which provides electrons and holes for a single electron light emitting element. The CGL generally includes N-CGL and P-CGL, which are used to generate electrons and holes, respectively. The CGL must have a low work function to reduce the operating voltage and power consumption, and have good LUMO and HUMO energy level matching with the adjacent charge transport layer to prevent charge accumulation and cause voltage drop at the P-N interface. In order to stabilize the P-N interface carriers, a metal stabilizing layer is generally provided between the N-CGL and the P-CGL.

[0004] However, the P-CGL generally dopes a hole transport material with an organic material having strong conductivity, so when the doping reaches a certain proportion, it is easy to cause lateral crosstalk under the action of an electric field; in addition, the doped material in the P-CGL has absorbance to visible light, especially blue light, and the metal stabilizing layer further prevents light extraction, resulting in reduced device efficiency; for the N-CGL, the material is generally an electron transport material doped with a low work function metal or alkali metal, which often leads to mismatched P-N carrier transport rates, resulting in high device operating voltage and poor life.

[0005] SUMMARY

[0006] The purpose of the present application is to provide a stacked OLED device, improve the structure of the stacked OLED device, improve its use effect, and increase the service life.

[0007] The present application solves the above technical problems by the following technical solutions:

[0008] The present application provides a stacked OLED device, comprising an anode layer, wherein one side of the anode layer is provided with a first light emitting layer, a charge generation layer, a second light emitting layer, a cathode layer and an optical extraction layer in sequence along a direction away from the anode layer.

[0009] The first light-emitting layer is sequentially provided with a first hole transport layer, a first electron blocking layer, a first pixel light-emitting layer, a first hole blocking layer and a first electron transport layer in the direction away from the anode layer, the second light-emitting layer is sequentially provided with a second hole transport layer, a second electron blocking layer, a second pixel light-emitting layer, a second hole blocking layer and a second electron transport layer in the direction away from the anode layer, and an optical adjustment layer is arranged between the second electron blocking layer and the second pixel light-emitting layer.

[0010] The charge generation layer is sequentially provided with an electron generation layer, a first hole generation layer and a second hole generation layer in the direction away from the anode layer; the charge generation layer is doped with an organic material having strong electron absorption capacity, and the doping proportion of the first hole generation layer is higher than that of the second hole generation layer.

[0011] In the technical solution, the charge generation layer is divided into multiple thin layers, the thickness and doping proportion of each layer in the charge generation layer are adjusted, the carrier rate between adjacent layers is matched, the obvious voltage drop at the interface between the adjacent two layers caused by charge accumulation is prevented, and the service life of the OLED device is prolonged; no metal stabilizing layer is arranged in the charge generation layer, the low transmittance in the visible light band is avoided to hinder light extraction, and thus the efficiency of the OLED device is improved.

[0012] In some embodiments, the doping proportion of the first hole generation layer and the doping proportion of the electron generation layer are both 5-10%.

[0013] In the technical solution, the doping proportion is adjusted to match the carrier rate at the interface between the first hole generation layer and the electron generation layer, the obvious voltage drop at the interface caused by charge accumulation is prevented, and the service life of the device is reduced.

[0014] In some embodiments, the doping proportion of the second hole generation layer is 0.5-1%.

[0015] In the technical solution, the doping proportion is adjusted to quickly transfer the carriers in the second hole generation layer and reduce the conductivity, thereby reducing the horizontal crosstalk in the OLED device.

[0016] In some embodiments, the materials of the first hole generation layer and the second hole generation layer are the same as those of the first hole transport layer and the second hole transport layer and are doped with HAT-CN.

[0017] In the technical solution, the hole generation layer uses the same material as the hole transport layer, the types of materials used in the production process are reduced, and the carrier rate is adjusted by doping HAT-CN.

[0018] In some embodiments, the material of the electron generation layer is the same material as the first electron transport layer and the second electron transport layer, and the electron generation layer is doped with alkali metal, and the electron generation layer and the first electron transport layer and the second electron transport layer all contain arylamine compounds.

[0019] In the technical solution, the electron generation layer uses the same material as the electron transport layer, reducing the types of materials used in the production process, and adjusting the carrier rate by doping alkali metal.

[0020] In some embodiments, the thickness of the electron generation layer and the second hole generation layer is greater than the thickness of the first hole generation layer.

[0021] In the technical solution, the first hole generation layer replaces the metal stabilization layer, and the carrier rate is coordinated by adjusting the thickness, while reducing the absorption of visible light and avoiding reducing the device efficiency.

[0022] In some embodiments, the thickness of the second hole generation layer is

[0023] In the technical solution, the second hole generation layer is set to an appropriate thickness to generate sufficient carriers and avoid affecting the carrier moving rate.

[0024] In some embodiments, the thickness of the first hole generation layer is

[0025] In the technical solution, the first hole generation layer is set to an appropriate thickness to coordinate the carrier moving rate between adjacent film layers and avoid the accumulation of charges at the interface, resulting in a pressure drop.

[0026] In some embodiments, the thickness of the electron generation layer is

[0027] In the technical solution, the electron generation layer is set to an appropriate thickness to generate sufficient carriers and avoid affecting the carrier moving rate.

[0028] In some embodiments, the first pixel light-emitting layer includes a first blue pixel light-emitting layer, a first green pixel light-emitting layer, and a first red pixel light-emitting layer, and the second pixel light-emitting layer includes a second blue pixel light-emitting layer, a second green pixel light-emitting layer, and a second red pixel light-emitting layer; the optical adjustment layer includes a green pixel light-emitting adjustment layer corresponding to the first green pixel light-emitting layer and the second green pixel light-emitting layer, and a red pixel light-emitting adjustment layer corresponding to the first red pixel light-emitting layer and the second red pixel light-emitting layer.

[0029] In the technical solution, the optical adjustment layer adjusts the visible light color value after passing through the charge generation layer, so that the visible light color value is basically consistent with the set value, and the display quality is improved.

[0030] On the basis of common knowledge in the art, the above-mentioned preferred conditions can be combined arbitrarily, thereby obtaining each preferred example of the present application.

[0031] The positive progress effect of the present application is that:

[0032] The stacked OLED device of the present application divides the charge generation layer into multiple thin layers, and by adjusting the thickness and doping ratio of each layer in the charge generation layer, the carrier velocity of each adjacent layer can be matched, so that the obvious voltage drop at the interface between the two adjacent layers caused by charge accumulation can be prevented, thereby prolonging the service life of the OLED device; and the charge generation layer does not have a metal stabilizing layer, which avoids the low transmittance in the visible light band from hindering light extraction, thereby improving the efficiency of the OLED device. BRIEF DESCRIPTION OF DRAWINGS

[0033] The above and other features and advantages of the present application will become more apparent by describing in detail example embodiments thereof with reference to the attached drawings.

[0034] FIG. 1 is a schematic diagram of a stacked OLED device according to an embodiment of the present application.

[0035] 1 anode layer 100 first light emitting layer 21 first hole transporting layer 31 first electron blocking layer 41 first pixel light emitting layer 411 first blue pixel light emitting layer 421 first green pixel light emitting layer 431 first red pixel light emitting layer 51 first hole blocking layer 61 first electron transporting layer 7 charge generation layer 71 electron generation layer 72 first hole generation layer 73 second hole generation layer 200 second light emitting layer 22 second hole transporting layer 32 second electron blocking layer 42 second pixel light emitting layer 412 second blue pixel light emitting layer 422 second green pixel light emitting layer 432 second red pixel light emitting layer 52 second hole blocking layer 62 second electron transporting layer 8 optical adjustment layer 81 green pixel optical adjustment layer 82 red pixel optical adjustment layer 9 cathode layer 10 light extraction layer DETAILED DESCRIPTION

[0036] The present application is herein described, by way of example only, with the assistance of the accompanying drawings wherein:

[0037] With reference to the drawings, the embodiments of the present application will be hereinafter described in detail. The present application can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. All the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0038] In the present specification, the expressions "one embodiment", "some embodiments", "exemplary", "detailed example", or "some examples" etc. mean that the particular feature, structure, material, or characteristic being referred to is included in at least one embodiment or example of the present application. Moreover, such expressions do not necessarily refer to the same embodiment or example. Furthermore, such expressions do not necessarily refer to any one or the same embodiment or example. In addition, if a specific feature, structure, material, or characteristic is referred to in a certain embodiment or example, it is understood that such feature, structure, material or characteristic can be combined with one or more other features, structures, materials or characteristics of the same or different embodiments or examples, but are not limited thereto.

[0039] Further, the terms "first", "second", etc. are used herein only to describe various elements, and do not imply or suggest relative importance or a number of the elements indicated. Thus, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the present specification, the meaning of "a plurality of" is two or more, unless specifically limited otherwise.

[0040] For the purpose of clear illustration of the present application, devices irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar constituent elements throughout the specification.

[0041] Throughout the specification, when it is said that a certain device is "connected" to another device, this includes not only the case of "direct connection", but also the case of "indirect connection" in which other elements are interposed therebetween. In addition, when it is said that a certain device "includes" a certain constituent element, other constituent elements are not excluded unless specifically stated to the contrary, but it means that other constituent elements can also be included.

[0042] When it is said that a certain device is "on" another device, it can be directly on the other device, but can also be accompanied by other devices therebetween. When it is said that a certain device is "directly" on another device, there are no other devices therebetween.

[0043] As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises", "comprising", "includes" and / or "including", when used herein, specify the presence of stated features, steps, operations, elements, components, items, and / or groups thereof, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, items, and / or groups thereof. As used herein, the terms "or" and "and / or" are to be interpreted as inclusive, i.e., as meaning one or any combination of the items. Thus, "A, B or C" or "A, B and / or C" means any of the following: A; B; C; A and B; A and C; B and C; A, B and C. Exceptions to this definition apply only when the combination of elements, functions, steps or acts are inherently mutually exclusive.

[0044] Although not differently defined, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Unless otherwise defined, terms used herein are to be interpreted in accordance with commonly used dictionaries and current usage by those skilled in the art, and not in an idealized or overly formal sense.

[0045] As shown in FIG. 1, the stacked OLED device in the embodiment includes an anode layer 1, and a first light-emitting layer 100, a charge generation layer 7, a second light-emitting layer 200, a cathode layer 9 and an optical extraction layer 10 are sequentially arranged on one side of the anode layer 1 in a direction away from the anode layer 1; the first light-emitting layer 100 includes a first hole transport layer 21, a first electron blocking layer 31, a first pixel light-emitting layer 41, a first hole blocking layer 51 and a first electron transport layer 61 sequentially arranged in a direction away from the anode layer 1; the second light-emitting layer 200 includes a second hole transport layer 22, a second electron blocking layer 32, a second pixel light-emitting layer 42, a second hole blocking layer 52 and a second electron transport layer 62 sequentially arranged in a direction away from the anode layer 1; the second electron blocking layer 32 and the second pixel light-emitting layer 42 are provided with an optical adjustment layer 8; the charge generation layer 7 includes an electron generation layer 71, a first hole generation layer 72 and a second hole generation layer 73 sequentially arranged in a direction away from the anode layer 1; the charge generation layer 7 is doped with an organic material having strong electron absorption capacity, and the doping proportion of the first hole generation layer 72 is higher than that of the second hole generation layer 73. The charge generation layer 7 is divided into multiple thin layers, and the carrier velocity matching between adjacent layers can be achieved by adjusting the thickness and doping proportion of each layer in the charge generation layer 7, so as to prevent the accumulation of charges and the occurrence of obvious voltage drop at the interface between the two adjacent layers, thereby prolonging the service life of the OLED device; and the charge generation layer 7 is not provided with a metal stabilizing layer, which avoids the low transmittance in the visible light band to hinder light extraction, thereby improving the efficiency of the OLED device.

[0046] The doping ratio of the first hole generation layer 72 and the doping ratio of the electron generation layer 71 are both 5%. The doping ratio is adjusted to match the carrier rate at the interface between the first hole generation layer 72 and the electron generation layer 71, prevent the accumulation of charges from causing a significant voltage drop at the interface, and reduce the service life of the device.

[0047] In other embodiments, the doping ratio of the first hole generation layer 72 and the doping ratio of the electron generation layer 71 can also be other values within the range of 5-10%, such as 7%; the doping ratio of the first hole generation layer 72 and the doping ratio of the electron generation layer 71 can also be different.

[0048] In this embodiment, the doping ratio of the second hole generation layer 73 is 1%. The doping ratio is adjusted to quickly transfer the carriers in the second hole generation layer 73 while reducing its conductivity, thereby reducing the lateral crosstalk in the OLED device.

[0049] In other embodiments, the doping ratio of the second hole generation layer 73 can also be other values within the range of 0.5-1%, such as 0.8%.

[0050] In this embodiment, the materials of the first hole generation layer 72 and the second hole generation layer 73 are the same materials as the first hole transport layer 21 and the second hole transport layer 22 doped with HAT-CN. The hole generation layer uses the same material as the hole transport layer, reducing the types of materials used in the production process, and the carrier rate is adjusted by doping HAT-CN.

[0051] In other embodiments, the first hole transport layer 21 and the second hole transport layer 22 can also be doped with other organic materials with strong electron absorption capacity according to product requirements.

[0052] The material of the electron generation layer 71 is the same material as the first electron transport layer 61 and the second electron transport layer 62 doped with alkali metals, and the electron generation layer 71 and the first electron transport layer 61 and the second electron transport layer 62 both contain arylamine compounds. The electron generation layer 71 uses the same material as the electron transport layer, reducing the types of materials used in the production process, and the carrier rate is adjusted by doping alkali metals.

[0053] The thicknesses of the electron generation layer 71 and the second hole generation layer 73 are both greater than the thickness of the first hole generation layer 72. The first hole generation layer 72 replaces the metal stabilization layer, and the carrier rate is coordinated by adjusting the thickness, while reducing the absorption of visible light and avoiding reducing the efficiency of the device.

[0054] The thickness of the second hole generation layer 73 is The second hole generation layer 73 is set to an appropriate thickness to generate sufficient carriers and also avoid affecting the carrier movement rate.

[0055] In other embodiments, the thickness of the second hole generation layer 73 can also be other values within the range, for example

[0056] In this embodiment, the thickness of the first hole generation layer 72 is The first hole generation layer 72 is set to an appropriate thickness to coordinate the carrier movement rate with adjacent film layers, avoiding the occurrence of charge accumulation at the interface resulting in pressure drop.

[0057] In other embodiments, the thickness of the first hole generation layer 72 can also be other values within the range, for example

[0058] In this embodiment, the thickness of the electron generation layer 71 is The electron generation layer is set to an appropriate thickness to generate sufficient carriers and also avoid affecting the carrier movement rate.

[0059] In other embodiments, the thickness of the electron generation layer 71 can also be other values within the range, for example

[0060] In this embodiment, the first pixel light-emitting layer 41 includes a first blue pixel light-emitting layer 411, a first green pixel light-emitting layer 421, and a first red pixel light-emitting layer 431, and the second pixel light-emitting layer 42 includes a second blue pixel light-emitting layer 412, a second green pixel light-emitting layer 422, and a second red pixel light-emitting layer 432; the optical adjustment layer 8 includes a green pixel light-emitting adjustment layer 81 corresponding to the first green pixel light-emitting layer 421 and the second green pixel light-emitting layer 422, and a red pixel light-emitting adjustment layer 82 corresponding to the first red pixel light-emitting layer 431 and the second red pixel light-emitting layer 432. The optical adjustment layer 8 adjusts the visible light color value after the charge generation layer 7 to keep it substantially consistent with the set value, improving display quality.

[0061] In summary, the purpose of the present application is to provide a laminated OLED device, improve the structure of the laminated OLED device, improve its use effect, and increase the service life.

[0062] The above is a further detailed description of the present application in combination with specific preferred embodiments, and cannot be considered as limiting the specific implementation of the present application to these descriptions. For ordinary skilled persons in the technical field to which the present application belongs, without departing from the concept of the present application, a number of simple deductions or substitutions can be made, which should be considered as falling within the protection scope of the present application.

Claims

1. A stacked OLED device, characterized in that, The anode layer (1) is sequentially provided with a first light-emitting layer (100), a charge generation layer (7), a second light-emitting layer (200), a cathode layer (9) and an optical extraction layer (10) in sequence along a direction away from the anode layer (1); The first light-emitting layer (100) is sequentially provided with a first hole transport layer (21), a first electron blocking layer (31), a first pixel light-emitting layer (41), a first hole blocking layer (51) and a first electron transport layer (61) in sequence along a direction away from the anode layer (1), and the second light-emitting layer (200) is sequentially provided with a second hole transport layer (22), a second electron blocking layer (32), a second pixel light-emitting layer (42), a second hole blocking layer (52) and a second electron transport layer (62) in sequence along a direction away from the anode layer (1), and an optical adjustment layer (8) is arranged between the second electron blocking layer (32) and the second pixel light-emitting layer (42). The charge generation layer (7) is sequentially provided with an electron generation layer (71), a first hole generation layer (72) and a second hole generation layer (73) in sequence along a direction away from the anode layer (1); the charge generation layer (7) is doped with an organic material having strong electron absorption capacity, and the doping proportion of the first hole generation layer (72) is higher than that of the second hole generation layer (73).

2. The OLED device of claim 1, wherein, The doping proportion of the first hole generation layer (72) and the doping proportion of the electron generation layer (71) are both 5-10%.

3. The OLED device of claim 2, wherein the first and second layers of the first electrode are formed of the same material. The doping proportion of the second hole generation layer (73) is 0.5-1%.

4. The OLED device of claim 1, wherein, The materials of the first hole generation layer (72) and the second hole generation layer (73) are the same as those of the first hole transport layer (21) and the second hole transport layer (22) and are doped with HAT-CN.

5. The OLED device of claim 1, wherein, The material of the electron generation layer (71) is the same as that of the first electron transport layer (61) and the second electron transport layer (62) and is doped with alkali metal, and the electron generation layer (71) and the first electron transport layer (61) and the second electron transport layer (62) all contain arylamine compounds.

6. The OLED device of claim 1, wherein, The thicknesses of the electron generation layer (71) and the second hole generation layer (73) are both greater than the thickness of the first hole generation layer (72).

7. The OLED device of claim 6, wherein the first and second layers of the first electrode are formed of the same material. The thickness of the second hole generation layer (73) is 8. The OLED device of claim 6, wherein the first and second layers of the first electrode are formed of the same material. The thickness of the first hole generation layer (72) is 9. The OLED device of claim 1, wherein, The thickness of the electron-generating layer (71) is 10. The OLED device of claim 1, wherein, The first pixel light-emitting layer (41) includes a first blue pixel light-emitting layer (411), a first green pixel light-emitting layer (421) and a first red pixel light-emitting layer (431), the second pixel light-emitting layer (42) includes a second blue pixel light-emitting layer (412), a second green pixel light-emitting layer (422) and a second red pixel light-emitting layer (432), the optical adjustment layer (8) includes a green pixel light-emitting adjustment layer (81) corresponding to the first green pixel light-emitting layer (421) and the second green pixel light-emitting layer (422), and a red pixel light-emitting adjustment layer (82) corresponding to the first red pixel light-emitting layer (431) and the second red pixel light-emitting layer (432).

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