Anode structure and OLED structure
By adopting an anode structure covered by isosceles trapezoidal PEDOT:PSS layer in the OLED structure, the problem of color gamut decrease in OLED structure at low brightness is solved, and higher luminescence stability and efficiency are achieved.
Patent Information
- Application Number
- CN202421250456.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-04
- Publication Date
- 2025-06-06
- Estimated Expiration
- 2034-06-04
AI Technical Summary
The existing OLED structure has inter-pixel crosstalk problem at low brightness, resulting in poor color gamut performance.
A new anode structure is adopted, wherein each pixel unit includes a first titanium nitride layer, an aluminum layer and a second titanium nitride layer sequentially stacked from bottom to top, and covers an isosceles trapezoidal PEDOT:PSS layer to avoid lateral leakage of HIL and HTL.
It effectively alleviates the problem of color gamut reduction in OLED structures at low brightness, improves luminous stability and efficiency, and reduces crosstalk between pixels.
Smart Images
Figure CN222954329U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of OLED packaging structures, and in particular relates to an anode structure and an OLED structure. Background Art
[0002] The pixel density of microdisplays is very high and the pitch is very small, about 1μm. The existing structure uses a common anode structure with tall-fence or single-layer undercut structure PDL, which will cause crosstalk between sub-pixels, resulting in poor color gamut performance of the product at low brightness.
[0003] Analysis found that this crosstalk is due to the high conductivity of the HIL, and the fact that it is made by full-surface evaporation during the manufacturing process, which causes the HIL to span between two pixels, resulting in lateral leakage between pixels. At low brightness, this leakage accounts for a very large proportion of the total drive current, causing RGB sub-pixel color mixing, which in turn causes a decrease in color gamut. Utility Model Content
[0004] The purpose of the utility model is to provide an anode structure and an OLED structure. The anode structure provided by the utility model can effectively alleviate the problem of reduced color gamut of the OLED structure under low brightness.
[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:
[0006] The utility model provides an anode structure, comprising a substrate and a plurality of pixel units distributed in an array on the surface of the substrate;
[0007] Each pixel unit includes an anode layer and a PEDOT:PSS layer covering the anode layer;
[0008] The transverse cross section of the PEDOT:PSS layer is an isosceles trapezoid;
[0009] The outermost pixel unit among the plurality of pixel units does not contact the edge of the substrate.
[0010] Preferably, the distance between two adjacent pixel units is greater than 500 nm.
[0011] Preferably, the anode layer comprises a first titanium nitride layer, an aluminum layer and a second titanium nitride layer stacked in sequence from bottom to top;
[0012] The thickness of the first titanium nitride layer is 3-20 nm, the thickness of the aluminum layer is 40-400 nm, and the thickness of the second titanium nitride layer is 3-10 nm.
[0013] Preferably, the thickness of the PEDOT:PSS layer on the anode layer is 50-300 nm; and the base angle of the isosceles trapezoid is less than or equal to 80°.
[0014] The utility model also provides an OLED structure, comprising a substrate, an anode, an electron blocking layer, a light-emitting layer, an electron transport layer, an electron injection layer and a cathode which are stacked in sequence from bottom to top;
[0015] The anode is the anode structure described in the above technical solution;
[0016] The electron blocking layer is in contact with the PEDOT:PSS layer and the substrate at the same time.
[0017] Preferably, the material of the electron blocking layer includes TCTA; the thickness of the electron blocking layer on each pixel unit is 5-20 nm.
[0018] Preferably, the light-emitting layer includes a light-emitting layer A or a light-emitting layer B;
[0019] The light-emitting layer A comprises a first light-emitting layer, an intermediate layer and a second light-emitting layer which are stacked in sequence;
[0020] The material of the first light-emitting layer includes a green light host material, a green light guest material and a red light guest material, and the thickness of the first light-emitting layer is 10nm; the material of the intermediate layer includes CBP or MCP, and the thickness of the intermediate layer is 0-5nm; the material of the second light-emitting layer includes a blue light host material and a blue light guest material, and the thickness of the second light-emitting layer is 10nm;
[0021] The materials of the light-emitting layer B include a blue light host material, a fluorescent green light guest material, a fluorescent red light guest material and a fluorescent blue light guest material; the thickness of the light-emitting layer B is 20 nm.
[0022] Preferably, the material of the electron transport layer includes TBPi or TmPyPB, and the thickness of the electron transport layer is 2 to 200 nm;
[0023] The material of the electron injection layer includes Liq or LiF, and the thickness of the electron injection layer is 1 to 20 nm;
[0024] The material of the cathode includes Ag, Mg / Ag or IZO, and the thickness of the cathode is 2-200 nm.
[0025] Preferably, the surface of the cathode further includes a packaging layer; the packaging layer includes a silicon nitride layer or an aluminum oxide layer.
[0026] The utility model provides an anode structure, including a substrate and a plurality of pixel units distributed in an array on the surface of the substrate; each pixel unit includes an anode layer and a PEDOT:PSS layer covering the anode layer; the transverse cross-section of the PEDOT:PSS layer is an isosceles trapezoid; the outermost pixel unit among the plurality of pixel units does not contact the edge of the substrate. The utility model uses photolithographically patterned PEDOT:PSS to replace the thicker continuous hole injection layer HIL and the hole transport layer HTL, wherein the isosceles trapezoidal structure can achieve better coverage, avoid lateral leakage of HIL and HTL, and greatly reduce the crosstalk problem between pixels. In addition, since there is no PDL design between each pixel unit, the OLED will not have large defects near the PDL, thereby reducing leakage between organic layers and improving light-emitting stability and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 A schematic diagram of the structure of the anode structure provided by the utility model;
[0028] Figure 2 A schematic diagram of the process of preparing the anode structure provided by the utility model;
[0029] Figure 3 A schematic diagram of the structure of the OLED provided by the utility model;
[0030] Figure 4 This is a color gamut test chart of the OLED structure obtained in Example 1 and Comparative Example 1. DETAILED DESCRIPTION
[0031] The utility model provides an anode structure, comprising a substrate and a plurality of pixel units distributed in an array on the surface of the substrate;
[0032] Each pixel unit includes an anode layer and a PEDOT:PSS layer covering the anode layer;
[0033] The transverse cross section of the PEDOT:PSS layer is an isosceles trapezoid;
[0034] The outermost pixel unit among the plurality of pixel units does not contact the edge of the substrate.
[0035] In the utility model, the anode layer preferably includes a first titanium nitride layer, an aluminum layer and a second titanium nitride layer stacked in sequence from bottom to top; the thickness of the first titanium nitride layer is preferably 3 to 20 nm, and more preferably 5 to 10 nm; the thickness of the aluminum layer is preferably 40 to 400 nm, and more preferably 80 to 300 nm; the thickness of the second titanium nitride layer is preferably 3 to 10 nm.
[0036] In the present invention, the PEDOT:PSS layer covers the anode layer, preferably contacts the anode layer and the substrate at the same time; the thickness of the PEDOT:PSS layer on the anode layer is preferably 50-300nm. In the present invention, the base angle of the isosceles trapezoid is preferably less than or equal to 80°.
[0037] In the present invention, the substrate preferably includes a CMOS backplane.
[0038] In the present invention, the distance between two adjacent pixel units is preferably greater than 500 nm.
[0039] In the present utility model, the structural schematic diagram of the anode structure is as follows Figure 1 shown.
[0040] The utility model also provides a method for preparing the anode structure described in the above technical solution, comprising the following steps:
[0041] Prepare a plurality of anode layers distributed in an array on the surface of the substrate;
[0042] A PEDOT:PSS layer is prepared on each anode layer by using a mask method to obtain the anode structure.
[0043] The present invention has no special limitation on the preparation method of the plurality of anode layers, and any method known to those skilled in the art can be adopted. In a specific embodiment of the present invention, the preparation method of the plurality of anode layers is preferably evaporation.
[0044] In the present invention, the mask method preferably includes the following steps:
[0045] Spin coating a PEDOT:PSS solution on the surface of the substrate and the plurality of anode layers to obtain a PEDOT:PSS overall layer;
[0046] After a protective layer and a photoresist layer are sequentially prepared on the surface of the PEDOT:PSS overall layer, etching is performed, and then the protective layer and the photoresist layer are removed.
[0047] In the present invention, the material of the protective layer preferably includes parylene or silicon nitride. The present invention has no special limitation on the thickness of the protective layer and the photoresist layer, and those skilled in the art can adopt the method known to those skilled in the art. The present invention has no special limitation on the etching process, and those skilled in the art can adopt the method known to those skilled in the art. In the present invention, the removal method preferably includes stripping or etching.
[0048] In the present invention, the schematic flow diagram of the method for preparing the anode structure is as follows: Figure 2 shown.
[0049] The utility model also provides the application of the anode structure described in the above technical solution or the anode structure prepared by the preparation method described in the above technical solution in an OLED structure.
[0050] The utility model also provides an OLED structure, comprising a substrate, an anode, an electron blocking layer, a light-emitting layer, an electron transport layer, an electron injection layer and a cathode which are stacked in sequence from bottom to top;
[0051] The anode is the anode structure described in the above technical solution or the anode structure prepared by the preparation method described in the above technical solution;
[0052] The electron blocking layer is in contact with the PEDOT:PSS layer and the substrate at the same time.
[0053] In the present invention, the material of the electron blocking layer preferably includes TCTA; the thickness of the electron blocking layer on each pixel unit is preferably 5-20 nm.
[0054] In the present invention, the light-emitting layer preferably includes a light-emitting layer A or a light-emitting layer B.
[0055] In the present invention, the light-emitting layer A preferably includes a first light-emitting layer, an intermediate layer, and a second light-emitting layer stacked in sequence. In the present invention, the material of the first light-emitting layer preferably includes a green light host material GH, a green light guest material GD, and a red light guest material RD; the green light host material is preferably mCP or CBP; the green light guest material is preferably Ir(ppy)3 or Ir(ppy)2acac; the red light guest material is preferably Ir(piq)3; the doping mass concentration of the green light guest material in the green light host material is preferably 6%; the doping mass concentration of the red light guest material in the green light host material is preferably 0.5%.
[0056] In the present invention, the thickness of the first light-emitting layer is 10 nm. In the present invention, the material of the intermediate layer preferably includes CBP or MCP, and the thickness of the intermediate layer is preferably 0-5 nm.
[0057] In the present invention, the material of the second light-emitting layer preferably includes a blue light host material BH and a blue light guest material BD, the blue light host material preferably includes ADN or mADN, and the blue light guest material preferably includes 4,4'-di(2,2'-distyryl]-1,1'-biphenyl (DPVBi); the doping mass concentration of the blue light guest material in the blue light host material is preferably 1-5%; the thickness of the second light-emitting layer is preferably 10nm.
[0058] In the present invention, the material of the light-emitting layer B preferably includes a blue light host material BH, a fluorescent green light guest material FGD, a fluorescent red light guest material FRD and a fluorescent blue light guest material FBD; the blue light host material is preferably ADN, the fluorescent green light guest material is preferably C545T, the fluorescent red light guest material is preferably DBP, and the fluorescent blue light guest material is preferably DPVBi. In the present invention, the doping mass concentration of the fluorescent green light guest material in the blue light host material is preferably 0.1-2%; the doping mass concentration of the fluorescent red light guest material in the blue light host material is preferably 0.1-2%; the doping mass concentration of the fluorescent blue light guest material in the blue light host material is preferably 0.5-5%. In the present invention, the thickness of the light-emitting layer B is preferably 20nm.
[0059] In the present invention, the material of the electron transport layer preferably includes TBPi or TmPyPB, and the thickness of the electron transport layer is preferably 2 to 200 nm.
[0060] In the present invention, the material of the electron injection layer preferably includes Liq or LiF, and the thickness of the electron injection layer is preferably 1 to 20 nm.
[0061] In the present invention, the material of the cathode preferably includes Ag, Mg / Ag or IZO, and the thickness of the cathode is preferably 2 to 200 nm.
[0062] In the present invention, the preparation methods of the electron blocking layer, the light-emitting layer, the electron transport layer, the electron injection layer and the cathode are preferably evaporation methods. The present invention has no special limitation on the evaporation method, and the method known to those skilled in the art can be used.
[0063] In the present invention, the surface of the cathode preferably further comprises an encapsulation layer TFE; the encapsulation layer preferably comprises a silicon nitride layer or an aluminum oxide layer; the thickness of the silicon nitride layer is preferably 500 to 2000 nm; the thickness of the aluminum oxide layer is preferably 30 to 100 nm. In the present invention, the preparation method of the encapsulation layer preferably comprises chemical vapor deposition or atomic layer deposition.
[0064] The structural schematic diagram of the OLED structure provided by the utility model is as follows Figure 3 As shown, 1 is a substrate, 2 is an anode layer, 3 is a PEDOT:PSS layer, 4 is an electron blocking layer, 5 is a light-emitting layer, 6 is an electron transport layer, 7 is an electron injection layer, and 8 is a cathode.
[0065] In order to further illustrate the present invention, an anode structure and an OLED structure provided by the present invention are described in detail below in conjunction with the accompanying drawings and embodiments, but they should not be construed as limiting the protection scope of the present invention.
[0066] Example 1
[0067] An anode layer distributed in a strip array is prepared on the surface of the CMOS backplane, wherein the structure of each anode layer from bottom to top is a first titanium nitride layer (5nm) / aluminum layer (80nm) / a second titanium nitride layer (3nm);
[0068] A PEDOT:PSS overall layer with a thickness of 150 nm is prepared by spin coating on the surface of the CMOS backplane and the anode layer, and then a silicon nitride protective layer and a photoresist layer with a thickness of 1000 nm are prepared on the surface of the PEDOT:PSS overall layer, and after etching, the protective layer and the photoresist layer are removed to obtain an anode structure, wherein the spacing between each pixel unit in the anode structure is 1 um, and the bottom angle of the PEDOT:PSS layer is 60°;
[0069] An electron blocking layer with a thickness of 5 nm (referring to the thickness on each pixel unit) is prepared on the surface of the CMOS backplane and the PEDOT:PSS layer, wherein the material of the electron blocking layer is TCTA;
[0070] A light-emitting layer is prepared on the surface of the electron blocking layer, wherein the structure of the light-emitting layer is GH:GD:RD(10nm) / IL(5nm) / BH:BD(10nm), wherein the material of GH is CBP, the material of GD is Ir(ppy)2acac, the material of RD is Ir(piq)3, and the doping mass concentrations of GD and RD in GH are 6% and 0.5% respectively; the material of IL is CBP; the material of BH is ADN, the material of BD is DPVBi, and the doping mass concentration of BD in BH is 2%;
[0071] An electron transport layer with a thickness of 40 nm is prepared on the surface of the light-emitting layer, wherein the material of the electron transport layer is TmPyPB;
[0072] An electron injection layer with a thickness of 1 nm is prepared on the surface of the electron transport layer, wherein the material of the electron injection layer is LiF;
[0073] An IZO layer with a thickness of 100 nm is prepared on the surface of the electron injection layer to obtain the OLED structure.
[0074] Example 2
[0075] A plurality of anode layers distributed in a strip array are prepared on the surface of the CMOS backplane, wherein the structure of each anode layer from bottom to top is a first titanium nitride layer (5nm) / aluminum layer (80nm) / a second titanium nitride layer (3nm);
[0076] A PEDOT:PSS overall layer with a thickness of 50 nm is prepared by spin coating on the surface of the CMOS backplane and the plurality of anode layers, and then a silicon nitride protective layer and a photoresist layer with a thickness of 1000 nm are prepared on the surface of the PEDOT:PSS overall layer, and after etching, the protective layer and the photoresist layer are removed to obtain an anode structure, wherein the spacing between each pixel unit in the anode structure is 1 um, and the bottom angle of the PEDOT:PSS layer is 60°;
[0077] An electron blocking layer with a thickness of 5 nm (referring to the thickness on each pixel unit) is prepared on the surface of the CMOS backplane and the PEDOT:PSS layer, wherein the material of the electron blocking layer is TCTA;
[0078] A light-emitting layer is prepared on the surface of the electron blocking layer, wherein the structure of the light-emitting layer is BH:FBD:FGD:FRD (20 nm), wherein the material of BH is ADN, the material of FBD is DPVBi, the material of FGD is C545T, the material of FRD is DBP, and the doping mass concentrations of FBD, FGD and FRD in BH are 1.5%, 0.8% and 0.3% respectively;
[0079] An electron transport layer with a thickness of 40 nm is prepared on the surface of the light-emitting layer, wherein the material of the electron transport layer is TmPyPB;
[0080] An electron injection layer with a thickness of 1 nm is prepared on the surface of the electron transport layer, wherein the material of the electron injection layer is LiF;
[0081] An indium zinc oxide (IZO) layer with a thickness of 100 nm is prepared on the surface of the electron injection layer to obtain the OLED structure.
[0082] Comparative Example 1
[0083] An anode layer distributed in a strip array is prepared on the surface of the CMOS backplane, wherein the structure of each anode layer from bottom to top is a first titanium nitride layer (5nm) / aluminum layer (80nm) / a second titanium nitride layer (3nm);
[0084] A hole injection layer with a thickness of 10 nm is prepared on the surface of the anode layer, wherein the material of the hole blocking layer is HAT-CN; a hole transport layer with a thickness of 40 nm is prepared on the surface of the hole injection layer, wherein the material of the hole transport layer is NPB; an electron blocking layer with a thickness of 5 nm is prepared on the surface of the hole transport layer, wherein the material of the electron blocking layer is TCTA; a light-emitting layer is prepared on the surface of the electron blocking layer, wherein the structure of the light-emitting layer is BH:FBD:FGD:FRD (20 nm), wherein the material of BH is ADN, the material of FBD is DPVBi, the material of FGD is C545T, the material of FRD is DBP, and the doping mass concentrations of FBD, FGD and FRD in BH are 1.5%, 0.8% and 0.3% respectively;
[0085] An electron transport layer with a thickness of 40 nm is prepared on the surface of the light-emitting layer, wherein the material of the electron transport layer is TmPyPB; an electron injection layer with a thickness of 1 nm is prepared on the surface of the electron transport layer, wherein the material of the electron injection layer is LiF; and an indium zinc oxide IZO layer with a thickness of 100 nm is prepared on the surface of the electron injection layer to obtain the OLED structure.
[0086] Performance Testing
[0087] Figure 1 The color gamut test diagrams of the OLED structures obtained in Example 1 and Comparative Example 1 show that the color gamut of the OLED structure obtained in the present invention can still achieve 70% NTSC color gamut below 10 nits; while the color gamut of the conventional structure in Comparative Example 1 has decreased at this brightness.
[0088] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.
Claims
1. An anode structure, characterized in that: It comprises a substrate and a plurality of pixel units distributed in an array on the surface of the substrate; Each pixel unit includes an anode layer and a PEDOT:PSS layer covering the anode layer; The transverse cross section of the PEDOT:PSS layer is an isosceles trapezoid; The outermost pixel unit among the plurality of pixel units does not contact the edge of the substrate.
2. The anode structure according to claim 1, characterized in that: The distance between two adjacent pixel units is greater than 500 nm.
3. The anode structure according to claim 1, characterized in that: The anode layer includes a first titanium nitride layer, an aluminum layer, and a second titanium nitride layer stacked in sequence from bottom to top; The thickness of the first titanium nitride layer is 3-20 nm, the thickness of the aluminum layer is 40-400 nm, and the thickness of the second titanium nitride layer is 3-10 nm.
4. The anode structure according to claim 1 or 3, characterized in that: The thickness of the PEDOT:PSS layer on the anode layer is 50-300 nm; the base angle of the isosceles trapezoid is less than or equal to 80°.
5. An OLED structure, characterized in that: It includes a substrate, an anode, an electron blocking layer, a light-emitting layer, an electron transport layer, an electron injection layer and a cathode which are stacked in sequence from bottom to top; The anode is the anode structure according to any one of claims 1 to 4; The electron blocking layer is in contact with the PEDOT:PSS layer and the substrate at the same time.
6. The OLED structure according to claim 5, characterized in that The material of the electron blocking layer includes TCTA; the thickness of the electron blocking layer on each pixel unit is 5-20 nm.
7. The OLED structure according to claim 5, characterized in that The light-emitting layer includes a light-emitting layer A or a light-emitting layer B; The light-emitting layer A comprises a first light-emitting layer, an intermediate layer and a second light-emitting layer which are stacked in sequence; The thickness of the first light-emitting layer is 10 nm; the thickness of the intermediate layer is 0 to 5 nm; the thickness of the second light-emitting layer is 10 nm; The thickness of the light-emitting layer B is 20 nm.
8. The OLED structure according to claim 5, characterized in that: The material of the electron transport layer includes TBPi or TmPyPB, and the thickness of the electron transport layer is 2 to 200 nm; The material of the electron injection layer includes Liq or LiF, and the thickness of the electron injection layer is 1 to 20 nm; The material of the cathode includes Ag, Mg / Ag or IZO, and the thickness of the cathode is 2-200 nm.
9. The OLED structure according to claim 5, characterized in that: The surface of the cathode further includes a packaging layer; the packaging layer includes a silicon nitride layer or an aluminum oxide layer.