Pixel structure and display for improving brightness and service life of light-emitting element

Abstract

The invention discloses a pixel structure for improving the brightness of a light-emitting element and prolonging the service life of the light-emitting element, which comprises a substrate, the substrate is provided with a plurality of light-emitting pixel areas, and each light-emitting pixel area is internally provided with a red light-emitting pixel point, a blue light-emitting pixel point and a green light-emitting pixel point, the red light-emitting pixel points and the green light-emitting pixel points are of organic light-emitting structures, and the blue light-emitting pixel points are of quantum dot light-emitting structures. The problems that the luminance, efficiency, service life and other properties of an existing blue OLED still need to be improved, and the service life is affected by the luminous efficiency in the blue OLED are solved.

Description

Technical Field

[0001] The present invention relates to the field of OLED light-emitting devices, and in particular to a pixel structure and a display for improving the brightness and life of a light-emitting element. Background Art

[0002] In the OLED light-emitting structure, the general three-color light-emitting device setting is realized through the host-guest doping luminescence mechanism. This mechanism uses a single host or co-doped host material to dope with fluorescent or phosphorescent materials to achieve electroluminescence. By matching the host material with the phosphorescent guest material, high-efficiency and high-purity luminescence can be achieved. At present, great progress has been made in red and green light emission, while the brightness, efficiency, lifespan and other performance of blue OLED still need to be improved, and blue OLED has always been accompanied by the contradiction between efficiency and lifespan. Summary of the invention

[0003] The present invention discloses a pixel structure for improving the brightness and life of a light-emitting element, which solves the problem that the brightness, efficiency and life of the existing blue light OLED still need to be improved, and the light-emitting efficiency in the blue OLED affects the life.

[0004] A pixel structure for improving the brightness and life of a light-emitting element comprises a substrate with a plurality of light-emitting pixel areas, each of the light-emitting pixel areas having a red light-emitting pixel point, a blue light-emitting pixel point, and a green light-emitting pixel point, wherein the red light-emitting pixel point and the green light-emitting pixel point are organic light-emitting structures, and the blue light-emitting pixel point is a quantum dot light-emitting structure.

[0005] The present application adopts a combination of a quantum dot light-emitting structure and an organic light-emitting structure, and uses a quantum dot light-emitting structure on a blue light-emitting pixel to replace a traditional organic light-emitting structure, thereby improving the light-emitting efficiency of the blue light-emitting pixel. Under the premise of not increasing the voltage, the brightness is increased relative to the organic light-emitting structure, thereby extending the service life in disguise.

[0006] Several optional methods are also provided below, but they are not intended to be additional limitations on the above-mentioned overall solution, but are merely further supplements or preferences. Under the premise that there are no technical or logical contradictions, each optional method can be combined with the above-mentioned overall solution separately, and multiple optional methods can also be combined.

[0007] Optionally, the quantum dot light-emitting structure includes a first anode layer, a first hole injection layer, a first hole transport layer, a blue light-emitting layer, a first electron transport layer, a first electron injection layer, a first cathode layer, and a first sealing layer stacked in sequence on the substrate.

[0008] Optionally, the organic light-emitting structure includes a second anode layer, a second hole injection layer, a second hole transport layer, an organic light-emitting layer, a second electron transport layer, a second electron injection layer, a second cathode layer, and a second sealing layer stacked in sequence on the substrate.

[0009] Optionally, the material for preparing the first hole injection layer is a PEDOT:PSS aqueous solution or polyaniline;

[0010] The material for preparing the second hole injection layer is metal oxide or organic semiconductor material.

[0011] Optionally, the material for preparing the first hole transport layer includes one or more of Poly-TPD, PVK, TFB, TPD, and CBP; the material for preparing the second hole transport layer includes one or more of NPB, TCTA, TAPC, TPDI, and FPCC.

[0012] Optionally, the material for preparing the first electron transport layer includes one or more of Alq3, TPBi, BPhen, TNF, ZnO, and TiO2; the material for preparing the second electron transport layer includes one or more of Alq3, TPBi, TPO, Bphen, and SiTAZ.

[0013] Optionally, the material for preparing the first electron injection layer is an alkali metal compound or an organic small molecule material; the material for preparing the second electron injection layer is one of an alkali metal oxide, an alkali metal fluoride, and an alkali metal chloride.

[0014] Optionally, the blue light emitting layer is prepared using quantum dot materials, and the quantum dot materials include one or more of II-VI group quantum dots, IV-VI group quantum dots, and III-V group quantum dots.

[0015] Optionally, the organic light-emitting layer is a red organic light-emitting layer or a green organic light-emitting layer.

[0016] The present application also discloses a display using a light-emitting element having the above-mentioned pixel structure.

[0017] The beneficial effects of this application are as follows:

[0018] In the present application, the blue light-emitting pixel is replaced by a quantum dot structure instead of the traditional organic light-emitting structure, which improves the luminous efficiency and brightness of the blue light-emitting pixel without increasing the voltage, thereby increasing the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of the light-emitting pixel area in this application;

[0020] Figure 2It is a schematic diagram of the local structure in this application;

[0021] Figure 3 This is a schematic diagram of the structure of the quantum dot light-emitting structure in this application;

[0022] Figure 4 It is a schematic diagram of the structure of the organic light-emitting structure in this application.

[0023] The reference numerals in the figures are described as follows:

[0024] 1. Light-emitting pixel area; 2. Organic light-emitting structure; 21. Second anode layer; 22. Second hole injection layer; 23. Second hole transport layer; 24. Organic light-emitting layer; 25. Second electron transport layer; 26. Second electron injection layer; 27. Second cathode layer; 28. Second sealing layer;

[0025] 3. Organic light-emitting structure; 4. Quantum dot light-emitting structure;

[0026] 41. first anode layer; 42. first hole injection layer; 43. first hole transport layer; 44. blue light emitting layer; 45. first electron transport layer; 46. first electron injection layer; 47. first cathode layer; 48. first sealing layer;

[0027] 5. Substrate. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0029] It should be noted that when a component is referred to as being "connected" to another component, it may be directly connected to the other component or there may be a central component. When a component is referred to as being "disposed on" another component, it may be directly disposed on the other component or there may be a central component at the same time.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0031] Embodiment 1

[0032] refer to Figure 1In one embodiment of the present application, a pixel structure for improving the brightness and life of a light-emitting element is disclosed, including a substrate with a plurality of light-emitting pixel areas, each of which has a red light-emitting pixel point, a blue light-emitting pixel point, and a green light-emitting pixel point. The red light-emitting pixel point and the green light-emitting pixel point are organic light-emitting structures, and the blue light-emitting pixel point is a quantum dot light-emitting structure.

[0033] exist Figure 1 The document discloses a structure of a light-emitting pixel area, in which there are adjacent red light-emitting pixel points, green light-emitting pixel points, and blue light-emitting pixel points, and the red light-emitting pixel points, green light-emitting pixel points, and blue light-emitting pixel points are arranged on the same side of a substrate.

[0034] Among them, reference Figure 2 The quantum dot light-emitting structure includes a first anode layer, a first hole injection layer, a first hole transport layer, a blue light-emitting layer, a first electron transport layer, a first electron injection layer, a first cathode layer, and a first sealing layer stacked in sequence on a substrate.

[0035] refer to Figure 3 , is an organic light-emitting structure representing red light-emitting pixels and green light-emitting pixels, which includes a second anode layer, a second hole injection layer, a second hole transport layer, an organic light-emitting layer, a second electron transport layer, a second electron injection layer, a second cathode layer, and a second sealing layer stacked in sequence on a substrate.

[0036] The present application adopts a combination of a quantum dot light-emitting structure and an organic light-emitting structure, and uses a quantum dot light-emitting structure on a blue light-emitting pixel to replace a traditional organic light-emitting structure, thereby improving the light-emitting efficiency of the blue light-emitting pixel. Under the premise of not increasing the voltage, the brightness is increased relative to the organic light-emitting structure, thereby extending the service life in disguise.

[0037] Embodiment 2

[0038] In one embodiment of the application, a method for preparing the above-mentioned pixel structure for improving the brightness and life of the light-emitting element is also disclosed, including:

[0039] Step 1: Take a substrate, apply photoresist on the substrate, and after exposure and development operations, form array grooves corresponding to the anode layer on the substrate.

[0040] As mentioned above, the photoresist can be applied by spin coating, printing, spraying, etc.

[0041] Step 2: preparing an anode layer on the substrate with the above array grooves.

[0042] Conductive metal is deposited on the side of the substrate with the array grooves by vacuum evaporation to form a metal film layer; and the photoresist on the substrate is stripped by a wet stripping process to retain the metal film layer in the array grooves to form an anode layer.

[0043] As mentioned above, in addition to vacuum evaporation, the metal film layer can also be deposited by vacuum sputtering, ion beam deposition, and plasma enhanced chemical vapor deposition;

[0044] As mentioned above, the conductive metal may be a metal alloy of Al or Ti. It should be supplemented that the material for preparing the anode layer may also be a transparent conductive oxide, such as ITO (indium tin oxide), IZO (indium zinc oxide), TO (tin oxide).

[0045] As mentioned above, the anode layer includes a first anode layer and a second anode layer.

[0046] Step three: prepare the first hole injection layer, the first hole transport layer, the blue light emitting layer, the first electron transport layer, and the first electron injection layer in sequence.

[0047] 1. Use a high-precision mask to partially block the anode layer to expose the first anode layer, and then deposit the first anode layer.

[0048] 2. Spin coating an aqueous solution of PEDOT:PSS (composed of two substances, PEDOT and PSS. PEDOT is a polymer of EDOT (3,4-ethylenedioxythiophene monomer) and PSS is polystyrene sulfonate) inorganic material on the first anode layer to form a first hole injection layer.

[0049] As mentioned above, the inorganic material of the aqueous solution of PEDOT:PSS can also be replaced by polyaniline.

[0050] 3. Then, one or more polymers such as Poly-TPD (poly-TPD), PVK (poly (9-vinyl carbazole)), TFB, TPD (N, N'-diphenyl-N, N'-dimethylcarbodiamine), CBP (4, 4'-N, N'-dicarbazole biphenyl) are coated by doping, mixed spin coating or orthogonal solution method to form a first hole transport layer on the first hole injection layer.

[0051] 4. Spin coating the quantum dot material onto the first hole transport layer to form a blue light emitting layer.

[0052] As mentioned above, the preparation material of the blue light emitting layer can be selected from Group II-VI quantum dots (e.g., Cd, Zn, Hg), Group III-V quantum dots (e.g., InP, InAs, GaAs, GaN), and Group IV-VI quantum dots (e.g., PbSe, PbS, SnSe, SnTe) as quantum dot materials; Perovskite quantum dots, carbon dots, and other types of colloidal quantum dots (e.g., CuInSe2, CuInS2, Ag2S) can also be selected for preparation;

[0053] Furthermore, the above-mentioned method for preparing the blue light emitting layer can be prepared by spin coating technology, or by roller transfer technology, inkjet printing, or printing.

[0054] 5. Cover the electron transport layer material on the blue light emitting layer by vacuum evaporation or solution preparation to obtain the first electron transport layer.

[0055] The electron transport layer materials mentioned above are organic materials such as Alq3 (tris(8-hydroxyquinoline)aluminum), TPBi (2,2',2"-(1,3,5-phenyltriylbenzene)tribenzyldiazonium), BPhen (4,7-diphenyl-1,10-phenanthroline), TNF (trinitronaphthalene) and rare earth complexes, as well as inorganic metal oxides such as ZnO and TiO2.

[0056] 6. Using a spin coating method or a vacuum evaporation method, the electron injection layer material is covered on the first electron transport layer to obtain the first electron injection layer.

[0057] The electron injection layer material mentioned above is alkali metal compounds such as calcium, palladium phenanthroline or organic small molecule materials.

[0058] Step 4: Prepare a second hole injection layer, a second hole transport layer, an organic light-emitting layer, a second electron transport layer, and a second electron injection layer in sequence.

[0059] A high-precision mask is used to partially block the anode layer to expose the second anode layer, and then the second anode layer is deposited.

[0060] As mentioned above, the preparation material of the second hole injection layer can be selected from transition metal oxides such as m-TDATA, MoO3, WO3, V2O5 and organic substances such as PEDOT:PSS, CuPc;

[0061] As mentioned above, the preparation material of the second hole transport layer can be selected from NPB, TCTA, TAPC, TPDI, and FPCC;

[0062] The organic light-emitting layer includes a green organic light-emitting layer and a red organic light-emitting layer. The green organic light-emitting layer can be prepared from materials such as Ir(ppy)3, Alq3, platinum complex, copper complex, and quinone compounds; the red organic light-emitting layer can be prepared from phosphorescent materials such as PtOEP, copper complex, rhenium complex, osmium complex, and iridium complex.

[0063] As mentioned above, the preparation material of the second electron transport layer can be selected from Alq3, TPBi, TPO, Bphen, SiTAZ (silicon tungsten zirconium alloy);

[0064] As mentioned above, the preparation material of the second electron injection layer can be selected from alkali metal oxides and fluorides and alkali metal chlorides such as Li2O, K2SiO3, Cs2CO3, CsF, LiF, and CaCl2.

[0065] Furthermore, the second hole injection layer, the second hole transport layer, the organic light emitting layer, the second electron transport layer, and the second electron injection layer can be prepared by vacuum evaporation;

[0066] In other embodiments, the second hole injection layer, the second hole transport layer, the organic light-emitting layer, the second electron transport layer, and the second electron injection layer can also be prepared by a solution method, spin coating, inkjet printing, laser thermal transfer, and organic vapor deposition.

[0067] It should be explained that the distribution of red light-emitting pixels and green light-emitting pixels is determined by the green organic light-emitting layer and the red organic light-emitting layer. Therefore, the red light-emitting pixels and the green light-emitting pixels need to be prepared separately by repeating step 4.

[0068] Step 5: Prepare the cathode layer.

[0069] The cathode layer mentioned above refers to a first cathode layer covering the first electron injection layer and a second cathode layer covering the second electron injection layer.

[0070] In some embodiments, the first cathode layer and the second cathode layer are a common cathode layer, that is, the first cathode layer and the second cathode layer are interconnected and integrated.

[0071] In other embodiments, the first cathode layer and the second cathode layer may be independent of each other and may be formed by vapor deposition after being shielded by a high-precision mask.

[0072] Furthermore, the cathode layer can be prepared using metal materials such as Al, Ag, Li, Ka, Ca, Mg, and LiF.

[0073] Step 6: Prepare the sealing layer.

[0074] Chemical vapor deposition thin films are used, and the materials used include: oxides such as AL2O3, AlN, TaC, Pd, ZnS, nitrides, carbides, metals, sulfides, fluorides, and polymers.

[0075] As mentioned above, the sealing layer includes a first sealing layer and a second sealing layer.

[0076] By performing the above steps 1 to 6, the preparation of the pixel structure for improving the brightness and life of the light-emitting element in the first embodiment is completed.

[0077] Embodiment 3

[0078] In one embodiment of the present application, a display is also disclosed. The light-emitting element of the display adopts the pixel structure in the above-mentioned embodiment 1 and has a light-emitting pixel area formed by a combination of a quantum dot light-emitting structure and an organic light-emitting structure.

[0079] Among them, in the luminescent pixel area, the red luminescent pixel points and the green luminescent pixel points are organic luminescent structures, and the blue luminescent pixel points are quantum dot luminescent structures.

[0080] The data in the table below compares the brightness, energy consumption, and lifespan of blue light-emitting pixels using organic light-emitting devices (OLED) and quantum dot light-emitting devices (QLED):

[0081]

[0082] The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. When the technical features in different embodiments are embodied in the same figure, it can be regarded that the figure also discloses the combination examples of the various embodiments involved.

[0083] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application.

Claims

1. A pixel structure for improving the brightness and life of a light-emitting element, comprising a substrate with a plurality of light-emitting pixel areas, characterized in that: Each of the light-emitting pixel areas has a red light-emitting pixel, a blue light-emitting pixel, and a green light-emitting pixel. The red light-emitting pixel and the green light-emitting pixel are organic light-emitting structures, and the blue light-emitting pixel is a quantum dot light-emitting structure.

2. A pixel structure for improving the brightness and life of a light-emitting element according to claim 1, characterized in that: The quantum dot light emitting structure includes sequentially stacked on the substrate, The first anode layer, the first hole injection layer, the first hole transport layer, the blue light emitting layer, the first electron transport layer, the first electron injection layer, the first cathode layer, and the first sealing layer.

3. A pixel structure for improving the brightness and life of a light-emitting element according to claim 2, characterized in that: The organic light emitting structure includes sequentially stacked on the substrate, A second anode layer, a second hole injection layer, a second hole transport layer, an organic light emitting layer, a second electron transport layer, a second electron injection layer, a second cathode layer, and a second sealing layer.

4. A pixel structure for improving the brightness and life of a light-emitting element according to claim 3, characterized in that: The material for preparing the first hole injection layer is a PEDOT:PSS aqueous solution or polyaniline; The material for preparing the second hole injection layer is metal oxide or organic semiconductor material.

5. A pixel structure for improving the brightness and life of a light-emitting element according to claim 4, characterized in that: The material for preparing the first hole transport layer includes one or more of Poly-TPD, PVK, TFB, TPD, and CBP; The material for preparing the second hole transport layer includes one or more of NPB, TCTA, TAPC, TPDI, and FPCC.

6. A pixel structure for improving the brightness and life of a light-emitting element according to claim 5, characterized in that: The material for preparing the first electron transport layer includes one or more of Alq3, TPBi, BPhen, TNF, ZnO, and TiO2; The material for preparing the second electron transport layer includes one or more of Alq3, TPBi, TPO, Bphen, and SiTAZ.

7. A pixel structure for improving the brightness and life of a light-emitting element according to claim 6, characterized in that: The material for preparing the first electron injection layer is an alkali metal compound or an organic small molecule material; The material for preparing the second electron injection layer is one of alkali metal oxide, alkali metal fluoride and alkali metal chloride.

8. A pixel structure for improving the brightness and life of a light-emitting element according to claim 7, characterized in that: The blue light emitting layer is prepared by using quantum dot materials, and the quantum dot materials include one or more of II-VI group quantum dots, IV-VI group quantum dots, and III-V group quantum dots.

9. A pixel structure for improving the brightness and life of a light-emitting element according to claim 8, characterized in that: The organic light-emitting layer is a red organic light-emitting layer or a green organic light-emitting layer.

10. A display, characterized in that: A light emitting element having the pixel structure described in claim 9 is used.

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