Organic electroluminescent display panel and AMOLED device

Abstract

The utility model provides an organic electroluminescence display panel and an AMOLED device, the display panel comprises an OLED light-emitting device, the OLED light-emitting device comprises a first electrode, a hole conducting layer, an electron blocking layer, a light-emitting layer, an electron conducting layer and a second electrode; the light-emitting layer comprises a green light-emitting layer, and a hole dopant layer is arranged between the hole conducting layer and the electron blocking layer corresponding to the green light-emitting layer. The hole dopant layer is additionally arranged between the hole conducting layer and the electron blocking layer corresponding to the green light-emitting layer, the energy level difference between the hole conducting layer and the electron blocking layer is reduced through the hole dopant layer, carrier transmission is improved, and resistance is reduced; furthermore, by increasing the thickness of the electron blocking layer, the I-V curve and the working voltage of the display panel are not affected by the thickness of the electron blocking layer, but exciton quenching can be reduced, so that the luminous efficiency of the display panel is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of display, in particular to an organic electroluminescent display panel and an AMOLED device. Background Art

[0002] Active-matrix organic light-emitting diode (AMOLED) display devices have become the first choice for today's mid-to-high-end mobile smart terminal products due to their technological advantages. However, since the display panel requires an extremely harsh operating environment during the evaporation, packaging, and assembly processes, if the environment deteriorates, it will cause various display problems on the display panel, resulting in low production yield and high costs. However, the demand for tablet computers and mobile phone wearable screens is also growing, and the low grayscale display effect of OLED screens is becoming more and more stringent. The existing hard-board AMOLED devices use glass as the packaging cover plate, and set isolation columns (Photo Spacer, SP) on the Thin Film Transistor (TFT) to support the glass cover plate. Mechanical contact causes the isolation column to be crushed, involving the most sites and with the highest probability of occurrence. Therefore, how to reduce the probability of isolation column crushing is very critical.

[0003] According to relevant literature, the reason why the isolation column is crushed and causes small black spots is that the cathode and the hole injection layer (HIL) in the OLED device overlap, which is equivalent to the pixel definition layer and the hole injection layer being connected in parallel, causing current shunting and reducing pixel brightness; among them, since the working resistance of the green pixel G is the largest, the green pixel G is also most likely to be shunted by the hole injection layer, and the brightness is reduced the most. In response to the above technical problems, the existing technology generally uses the hole dopant in the AMOLED panel structure only for the hole injection layer on the upper layer of ITO, in order to raise its HUMO energy level, so that the energy level difference that needs to be overcome for hole injection becomes smaller, which is conducive to injection and reduces the OLED driving voltage.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to those skilled in the art. Utility Model Content

[0005] In view of the problems in the prior art, the purpose of the present invention is to provide an organic electroluminescent display panel and an AMOLED device.

[0006] The first aspect of the utility model provides an organic electroluminescent display panel, comprising an OLED light-emitting device, wherein the OLED light-emitting device comprises a first electrode, a hole conductive layer, an electron blocking layer, a light-emitting layer, an electron conductive layer and a second electrode;

[0007] The light-emitting layer comprises a green light-emitting layer, and a hole dopant layer is arranged between the hole conductive layer and the electron blocking layer corresponding to the green light-emitting layer.

[0008] According to the first aspect of the present invention, the thickness of the hole dopant layer is to between.

[0009] According to the first aspect of the present invention, the thickness of the electron blocking layer is greater than or equal to

[0010] According to the first aspect of the utility model, the hole conductive layer includes a hole injection layer, a first hole transport layer and a second hole transport layer.

[0011] According to the first aspect of the utility model, the hole conductive layer further includes a dopant.

[0012] According to the first aspect of the present invention, the highest occupied molecular orbital of the hole dopant layer is between the highest occupied molecular orbital of the second hole transport layer and the highest occupied molecular orbital of the electron blocking layer.

[0013] According to the first aspect of the utility model, the light-emitting layer further includes a red light-emitting layer and / or a blue light-emitting layer.

[0014] According to the first aspect of the utility model, the display panel further includes a substrate and a pixel circuit array layer.

[0015] A second aspect of the utility model provides an AMOLED device, comprising the organic electroluminescent display panel described above.

[0016] The utility model adds a hole dopant layer between the hole conductive layer and the electron blocking layer corresponding to the green light-emitting layer, reduces the energy level difference between the hole conductive layer and the electron blocking layer through the hole dopant layer, improves carrier transmission, and reduces resistance; further, by increasing the thickness of the electron blocking layer, the thickness of the electron blocking layer does not affect the IV curve and the operating voltage of the display panel, but can reduce exciton quenching, thereby improving the luminous efficiency of the display panel. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Other features, objectives and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings.

[0018] Figure 1 A schematic diagram of the structure of an organic electroluminescent display panel according to an embodiment of the present invention; and

[0019] Figure 2 The graph is a luminous brightness curve of a green pixel of an organic electroluminescent display panel with a conventional structure and a green pixel of an organic electroluminescent display panel according to an embodiment of the present invention. DETAILED DESCRIPTION

[0020] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that the utility model will be comprehensive and complete, and the concept of the example embodiments will be fully conveyed to those skilled in the art. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the utility model, and should not be construed as limitations on the utility model. The same reference numerals in the figures represent the same or similar structures, and thus their repeated description will be omitted.

[0021] In the description of the present invention, it should be understood that the terms "first" and "second" 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. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0022] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 a mechanical connection, an electrical connection, or can communicate with each other; 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. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0023] The disclosure below provides many different embodiments or examples for realizing different structures of the utility model. In order to simplify the disclosure of the utility model, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the utility model. In addition, the utility model can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplicity and clarity, and does not indicate the relationship between the various embodiments and / or settings discussed in itself. In addition, the utility model provides various specific examples of processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0024] In view of the existing technical problems, the utility model provides an organic electroluminescent display panel and an AMOLED device, wherein the display panel includes an OLED light-emitting device, wherein the OLED light-emitting device includes a first electrode, a hole conductive layer, an electron blocking layer, a light-emitting layer, an electron conductive layer and a second electrode; the light-emitting layer includes a green light-emitting layer, and a hole dopant layer is provided between the hole conductive layer and the electron blocking layer corresponding to the green light-emitting layer. The utility model adds a hole dopant layer between the hole conductive layer and the electron blocking layer corresponding to the green light-emitting layer, reduces the energy level difference between the hole conductive layer and the electron blocking layer through the hole dopant layer, improves carrier transmission, and reduces resistance; further, by increasing the thickness of the electron blocking layer, the thickness of the electron blocking layer does not affect the IV curve and the operating voltage of the display panel, but can reduce exciton quenching, thereby improving the luminous efficiency of the display panel.

[0025] The structures of the organic electroluminescent display panel and the AMOLED device of the present invention are further described below in conjunction with the accompanying drawings and specific embodiments. It can be understood that the various specific embodiments are not intended to limit the protection scope of the present invention.

[0026] Figure 1 The schematic diagram of the structure of an organic electroluminescent display panel of an embodiment of the utility model is shown in FIG. 1 . Specifically, the organic electroluminescent display panel includes an OLED light-emitting device 3, and the OLED light-emitting device 3 includes a first electrode 31, a hole conductive layer, an electron blocking layer 33, a light-emitting layer 35, an electron conductive layer and a second electrode 37. The display panel also includes a base substrate 1 and a pixel circuit array layer 2.

[0027] Figure 1In the embodiment of the invention, the light-emitting layer includes a green light-emitting layer G, a red light-emitting layer R and a blue light-emitting layer B. The green light-emitting layer G and the corresponding first electrode 31, the hole conductive layer, the electron blocking layer 33, the electron conductive layer and the second electrode 37 constitute a green pixel, emitting green light; the red light-emitting layer R and the corresponding first electrode 31, the hole conductive layer, the electron blocking layer 33, the electron conductive layer and the second electrode 37 constitute a red pixel, emitting red light; the blue light-emitting layer B and the corresponding first electrode 31, the hole conductive layer, the electron blocking layer 33, the electron conductive layer and the second electrode 37 constitute a blue pixel, emitting blue light.

[0028] The green pixel is different from the red pixel or the blue pixel in that a hole dopant layer 34 is provided between the hole conductive layer and the electron blocking layer of the green pixel. The hole conductive layer includes a hole injection layer 321, a first hole transport layer 322, and a second hole transport layer 323. The electron conductive layer may include an electron transport layer 361 and an electron injection layer 362. The thickness of the hole dopant layer 34 is to At this time, the hole dopant layer 34 disposed between the hole conductive layer and the electron blocking layer 33 is actually disposed between the second hole transport layer 323 and the electron blocking layer 33 .

[0029] In an embodiment, the hole dopant layer 34 may be a evaporated NPD-9 layer, the thickness of which is to Preferably, the thickness of the hole dopant layer 34 is The hole conductive layer 32 also includes a dopant, that is, the hole injection layer can be a doped mixed vapor layer. For example, the hole conductive layer 32 can be HIL:AD (30+70_0.5P) means that the thickness of the hole injection layer is The doping amount of the dopant in the hole injection layer near the first hole transport layer 322 is 0.5% (molar percentage), and the doping amount of the dopant can also be 1.5%, etc., which can be designed according to the highest occupied molecular orbital (HOMO) and the highest occupied molecular orbital (HOMO) of the hole injection layer and the first hole transport layer.

[0030] The materials of each layer of the organic electroluminescent display panel of the present invention are all materials of the prior art. In the present invention, only one of them is given as an example. The constituent materials of each layer of the organic electroluminescent display panel of one embodiment are as follows:

[0031] First electrode: indium tin oxide (ITO) with a thickness of 75 nm;

[0032] Hole injection layer: thickness The main material is NPB, and the doping material is NPD-9;

[0033] First hole transport layer: NPB with a thickness of 130 nm;

[0034] The second hole transport layer has a thickness of TDAB;

[0035] Electron blocking layer: thickness Methylcyclopentenolone (Mcp),

[0036] Green light-emitting layer: thickness CPB, doped with 11% Ir(ppy)3;

[0037] Electron transport layer: thickness BCP;

[0038] Electron injection layer: thickness Yb; and

[0039] Cathode: Mg / Ag layer with a thickness of 13 nm.

[0040] Preferably, the highest occupied molecular orbital (HOMO) of the hole dopant layer 34 is between the highest occupied molecular orbital of the second hole transport layer, more specifically, the second hole transport layer 323 , and the highest occupied molecular orbital of the electron blocking layer 33 .

[0041] In the above embodiment, the thickness of the electron blocking layer 33 is From the energy level distribution, the energy level difference (potential barrier) between the second hole transport layer 323 and the electron blocking layer 33 is large, and the hole dopant layer 34 can deepen the HOMO energy level of the second hole transport layer 323, reduce the energy level difference between the second hole transport layer 323 and the electron blocking layer 33, and increase the carrier transmission rate, thereby reducing the green light working resistance and effectively improving the low grayscale isolation column crushing phenomenon. However, experiments show that when the thickness of the electron blocking layer 33 is small, such as When the carriers are more easily quenched, the luminous efficiency is reduced. Therefore, in the present invention, preferably, the thickness of the electron blocking layer is greater than or equal to Figure 2 The luminance curves of the green pixel A of the organic electroluminescent display panel with the prior art structure and the green pixel B of the organic electroluminescent display panel according to an embodiment of the present invention are shown. It can be seen that the luminance reduction of the green pixel of the organic electroluminescent display panel of the present invention is reduced.

[0042] The utility model also provides an AMOLED device, including the organic electroluminescent display panel described above. The green pixel of the AMOLED device of the utility model is provided with a hole dopant layer between the hole conductive layer and the electron blocking layer, so as to reduce the working resistance of the green pixel, reduce the isolation column voltage, and reduce the current shunting of the green pixel due to the parallel connection of the pixel definition layer and the hole injection layer, thereby reducing the brightness reduction of the green pixel, so that the AMOLED device has a more uniform display performance.

[0043] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present invention.

[0044] The above contents are further detailed descriptions of the present invention in combination with specific preferred implementations, and the specific implementation of the present invention cannot be considered to be limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. An organic electroluminescent display panel, characterized in that: An OLED light-emitting device includes a first electrode, a hole conductive layer, an electron blocking layer, a light-emitting layer, an electron conductive layer and a second electrode; The light-emitting layer comprises a green light-emitting layer, and a hole dopant layer is arranged between the hole conductive layer and the electron blocking layer corresponding to the green light-emitting layer.

2. The organic electroluminescent display panel according to claim 1, characterized in that: The thickness of the hole dopant layer is to between.

3. The organic electroluminescent display panel according to claim 1, characterized in that: The thickness of the electron blocking layer is greater than or equal to 4. The organic electroluminescent display panel according to claim 1, characterized in that: The hole conductive layer includes a hole injection layer, a first hole transport layer and a second hole transport layer.

5. The organic electroluminescent display panel according to claim 4, characterized in that: The hole conducting layer further includes a dopant.

6. The organic electroluminescent display panel according to claim 5, characterized in that: The highest occupied molecular orbital of the hole dopant layer is between the highest occupied molecular orbital of the second hole transport layer and the highest occupied molecular orbital of the electron blocking layer.

7. The organic electroluminescent display panel according to claim 1, characterized in that: The light-emitting layer further includes a red light-emitting layer and / or a blue light-emitting layer.

8. The organic electroluminescent display panel according to claim 1, characterized in that: The display panel also includes a base substrate and a pixel circuit array layer.

9. An AMOLED device, characterized in that: Comprising the organic electroluminescent display panel according to any one of claims 1 to 8.

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