QLED device and preparation method thereof

Abstract

The present invention discloses a QLED device, which comprises: a first electrode, a first p-n type charge generation layer, a quantum dot light emitting layer, a second p-n type charge generation layer and a second electrode which are stacked in sequence, wherein the first p-n type charge generation layer comprises a plurality of first p-type charge generation units and a first n-type charge generation unit, and the second p-n type charge generation layer comprises a plurality of second p-type charge generation units and a second n-type charge generation unit, and by arranging the first p-type charge generation unit and the first n-type charge generation unit in the same layer and alternately at intervals along a first direction, and arranging the second p-type charge generation unit and the second n-type charge generation unit in the same layer and alternately at intervals along the first direction, it can be realized that both electrons and holes can be transmitted in the same layer, and the QLED device can be alternately lit under positive and negative bias voltages. Under high frequency alternating current, a stable lighting visual effect can be produced.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and in particular to a QLED device and a method for preparing the same. Background Art

[0002] Quantum dot light-emitting diodes (QLEDs), as a new type of high-efficiency electroluminescent device, have attracted widespread attention in recent years due to their advantages such as flexibility, light weight, good luminescence performance, high color purity, good color temperature, long service life and simple preparation process.

[0003] Most of the current QLED devices are direct current electroluminescent devices. Their working principle is to load direct current on both ends of the first electrode and the second electrode. Under the positive bias, the electrons and holes generated by the first electrode and the second electrode move to the opposite side and enter the quantum dot light-emitting layer, combining to generate excitons, and the excitons recombine to emit light. However, this light-emitting method faces some problems. The electricity used in life and production is mainly 220V alternating current. In order to ensure the normal operation of direct current QLED devices, it is necessary to add complex AC-DC conversion devices, which greatly increases the complexity and cost of the system. In addition, from the perspective of device structure, under direct current drive, in order to achieve carrier injection balance, QLED devices usually adopt a multi-layer film structure. The device structure is complex, and the continuous injection of carriers will produce an accumulation effect of charge. The aggregation of electron transport materials and hole transport materials on one side is not conducive to the life of the material, which accelerates the damage of the material structure and the aging of the device, causing the QLED device to gradually produce dark spots, thereby destroying the entire device.

[0004] AC-driven QLED devices are mainly lit by switching between positive and negative currents or doping hole injection layer (HIL) materials and electron injection layer (ETL) materials into the light-emitting layer in a certain proportion. However, the positive and negative current switching method often requires a complex multi-layer film structure, and most film materials need to be realized by vacuum evaporation, which invisibly increases the production cost and process complexity; and doping hole injection layer (HIL) materials and electron injection layer (ETL) materials into the light-emitting layer in a certain proportion will reduce the injection efficiency of carriers and affect the photoelectric performance of the device. In addition, the device only emits light in half of the forward drive cycle, and the brightness of the light changes continuously, affecting the display effect of the device. Summary of the invention

[0005] In view of this, an embodiment of the present invention provides a QLED device that is driven by AC and has stable light emission, and a method for preparing the QLED device.

[0006] In a first aspect, an embodiment of the present invention provides a QLED device, comprising: a first electrode, a first pn-type charge generation layer, a quantum dot light-emitting layer, a second pn-type charge generation layer, and a second electrode, which are sequentially stacked;

[0007] The first pn-type charge generation layer includes a plurality of first p-type charge generation units and a plurality of first n-type charge generation units, and the first p-type charge generation units and the first n-type charge generation units are in the same layer and are alternately arranged along a first direction;

[0008] The second pn-type charge generation layer includes a plurality of second p-type charge generation units and a plurality of second n-type charge generation units, and the second p-type charge generation units and the second n-type charge generation units are in the same layer and are alternately arranged along the first direction;

[0009] The orthographic projection of the first p-type charge generating unit on the plane of the QLED device and the orthographic projection of the second n-type charge generating unit on the plane of the QLED device have at least one overlapping area, and the orthographic projection of the second p-type charge generating unit on the plane of the QLED device and the orthographic projection of the first n-type charge generating unit on the plane of the QLED device have at least one overlapping area, so that the QLED device can produce a stable lighting visual effect.

[0010] In some embodiments, the QLED device further includes a first dielectric layer between the first electrode and the first pn-type charge generation layer, and / or a second dielectric layer between the second electrode and the second pn-type charge generation layer.

[0011] In some embodiments, the material of the first dielectric layer includes one or more of an organic polymer material and a metal oxide, and the material of the second dielectric layer includes one or more of an organic polymer material and a metal oxide.

[0012] In some embodiments, the organic polymer material includes but is not limited to polyvinyl pyrrolidone, polymethyl methacrylate, etc.; the metal oxide includes but is not limited to silicon dioxide, aluminum oxide, hafnium oxide, zirconium oxide, etc.

[0013] In some embodiments, the thickness of the first dielectric layer and the second dielectric layer is 10 nanometers to 50 micrometers.

[0014] In some embodiments, the first p-type charge generation unit has the same thickness as the first n-type charge generation unit, and the second p-type charge generation unit has the same thickness as the second n-type charge generation unit.

[0015] In some embodiments, the orthographic projection of the first p-type charge generation unit on the QLED device plane coincides with the orthographic projection of the second n-type charge generation unit on the QLED device plane, and the orthographic projection of the second p-type charge generation unit on the QLED device plane coincides with the orthographic projection of the first n-type charge generation unit on the QLED device plane.

[0016] In some embodiments, the material of the first p-type charge generation unit includes PEDOT:PSS, TFB, poly-TPD, PVK or PEDOT material, or molybdenum oxide material doped with one or more of copper, iron, aluminum, and nickel, and the material of the second p-type charge generation unit includes PEDOT:PSS, TFB, poly-TPD, PVK or PEDOT material, or molybdenum oxide material doped with one or more of copper, iron, aluminum, and nickel; and / or,

[0017] The material of the first n-type charge generation unit includes zinc oxide nanoparticles, or zinc oxide nanoparticles doped with one or more of aluminum, lithium, lanthanum, indium, and magnesium; the material of the second n-type charge generation unit includes zinc oxide nanoparticles, or zinc oxide nanoparticles doped with one or more of aluminum, lithium, lanthanum, indium, and magnesium.

[0018] In some embodiments, the material of the first p-type charge generation unit is composed of PEDOT:PSS, TFB, poly-TPD, PVK or PEDOT material, or molybdenum oxide material doped with one or more of copper, iron, aluminum, and nickel, and the material of the second p-type charge generation unit is composed of PEDOT:PSS, TFB, poly-TPD, PVK or PEDOT material, or molybdenum oxide material doped with one or more of copper, iron, aluminum, and nickel; and / or,

[0019] The material of the first n-type charge generation unit consists of zinc oxide nanoparticles, or zinc oxide nanoparticles doped with one or more of aluminum, lithium, lanthanum, indium, and magnesium; the material of the second n-type charge generation unit consists of zinc oxide nanoparticles, or zinc oxide nanoparticles doped with one or more of aluminum, lithium, lanthanum, indium, and magnesium.

[0020] In some embodiments, the thickness of the first pn-type charge generation layer is 5 nanometers to 50 nanometers, and the thickness of the second pn-type charge generation layer is 5 nanometers to 50 nanometers.

[0021] In some embodiments, the first electrode material may be an ITO conductive film, silver nanowires, or other conductive oxides; the material of the second electrode includes but is not limited to Au, Ag, Cu, Al, and alloys and laminated structures thereof.

[0022] In some embodiments, the QLED device further includes: a pixel defining structure disposed between the first p-type charge generating unit and the first n-type charge generating unit, and between the second p-type charge generating unit and the second n-type charge generating unit.

[0023] In some embodiments, the first p-type charge generating unit includes a plurality of first p-type charge generating sub-units adjacently arranged along the second direction, and the first n-type charge generating unit includes a plurality of first n-type charge generating sub-units adjacently arranged along the second direction; and the second p-type charge generating unit includes a plurality of second p-type charge generating sub-units adjacently arranged along the second direction, and the second n-type charge generating unit includes a plurality of second n-type charge generating sub-units adjacently arranged along the second direction.

[0024] In a second aspect, the present invention further provides a method for preparing a QLED device, comprising:

[0025] A first electrode, a first pn-type charge generation layer, a quantum dot light-emitting layer, a second pn-type charge generation layer and a second electrode are sequentially stacked to form;

[0026] The first pn-type charge generation layer includes a plurality of first p-type charge generation units and a plurality of first n-type charge generation units, and the first p-type charge generation units and the first n-type charge generation units are in the same layer and are alternately arranged along a first direction;

[0027] The second pn-type charge generation layer includes a plurality of second p-type charge generation units and a plurality of second n-type charge generation units, and the second p-type charge generation units and the second n-type charge generation units are in the same layer and are alternately arranged along the first direction;

[0028] The orthographic projection of the first p-type charge generating unit on the QLED device plane and the orthographic projection of the second n-type charge generating unit on the QLED device plane have at least one overlapping area, and the orthographic projection of the second p-type charge generating unit on the QLED device plane and the orthographic projection of the first n-type charge generating unit on the QLED device plane have at least one overlapping area.

[0029] In some embodiments, the formation of the first pn-type charge generation layer includes:

[0030] By using a solution method, a first p-type charge generating unit is formed in alternate rows above the first electrode; a first n-type charge generating unit is formed in alternate rows at a row adjacent to the first p-type charge generating unit; or

[0031] By using a solution method, first n-type charge generation units are formed in alternate rows above the first electrode; and first p-type charge generation units are formed in alternate rows at rows adjacent to the first n-type charge generation units.

[0032] In some embodiments, the formation of the second pn-type charge generation layer comprises:

[0033] By using a solution method, second p-type charge generation units are formed in alternate rows above the quantum dot light-emitting layer; second n-type charge generation units are formed in alternate rows at the rows adjacent to the second p-type charge generation units; or

[0034] By using a solution method, second n-type charge generation units are formed in alternate rows above the quantum dot light-emitting layer; and second p-type charge generation units are formed in alternate rows at rows adjacent to the second n-type charge generation units.

[0035] In some embodiments, the formation of the first pn-type charge generation layer includes:

[0036] By inkjet printing, first p-type charge generating units are inkjet printed in alternate lines above the first electrode; first n-type charge generating units are inkjet printed in alternate lines at the adjacent lines to the first p-type charge generating units; or

[0037] By using the inkjet printing method, the first n-type charge generating units are inkjet printed in alternate lines above the first electrode; and the first p-type charge generating units are inkjet printed in alternate lines at the rows adjacent to the first n-type charge generating units.

[0038] In some embodiments, the formation of the second pn-type charge generation layer comprises:

[0039] Using inkjet printing, above the quantum dot light-emitting layer, inkjet prints second p-type charge generating units in alternate rows; and in the rows adjacent to the second p-type charge generating units, inkjet prints second n-type charge generating units in alternate rows; or

[0040] By using the inkjet printing method, the second n-type charge generating units are inkjet printed in alternate lines above the quantum dot light-emitting layer; and the second p-type charge generating units are inkjet printed in alternate lines at the rows adjacent to the second n-type charge generating units.

[0041] In some embodiments, before forming the first pn-type charge generation layer, the method further includes: forming a first dielectric layer on the first electrode; and / or before forming the second electrode, the method further includes: forming a second dielectric layer on the second pn-type charge generation layer.

[0042] In some embodiments, the first electrode is formed by magnetron sputtering, and the material of the first electrode is ITO.

[0043] In some embodiments, the second electrode is formed by vacuum evaporation, and the material of the second electrode is Ag.

[0044] In a third aspect, the present invention further provides a QLED display device, comprising the QLED device described in any one of the embodiments in the first aspect, or comprising the QLED device prepared by the method described in any one of the embodiments in the second aspect.

[0045] The present invention provides a QLED device, which can realize that both electrons and holes can be transmitted in the same layer by arranging a first p-type charge generating unit and a first n-type charge generating unit in the same layer and alternately in a first direction, and a second p-type charge generating unit and a second n-type charge generating unit in the same layer and alternately in a first direction, and the QLED device can be alternately lit under positive and negative bias voltages. Under high-frequency alternating current, due to the perception latency of the human eye, the QLED device can produce a stable lighting visual effect.

[0046] The present invention also provides a method for preparing a QLED device, by which a QLED device with AC drive, stable light emission, high light emission efficiency and high brightness can be provided; and the provided method does not require a complex film layer structure or a complex current conversion device, thereby reducing the complexity of system integration and can significantly reduce production costs for large-scale production; in addition, both the pn-type charge generation layer and the light-emitting layer can be prepared by inkjet printing, which is simple to operate and can also significantly reduce production costs for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for describing the embodiments are briefly introduced below.

[0048] Figure 1 is a schematic diagram of a planar structure of a QLED device provided by an embodiment of the present invention;

[0049] Figure 2 An embodiment of the present invention provides Figure 1 The schematic cross-sectional structure diagram of the QLED device shown is obtained by cutting along the PP direction;

[0050] Figure 3 Another embodiment of the present invention provides Figure 1 The schematic cross-sectional structure diagram of the QLED device shown is obtained by cutting along the PP direction;

[0051] Figure 4 Another embodiment of the present invention provides Figure 1 The schematic cross-sectional structure diagram of the QLED device shown is obtained by cutting along the PP direction;

[0052] Figure 5 An embodiment of the present invention provides Figure 1 The schematic diagram of the cross-sectional structure of the QLED device shown is obtained by cutting along the PP direction;

[0053] Figure 6 is a schematic diagram of the planar structure of a first pn-type charge generation layer provided by an embodiment of the present invention;

[0054] Figure 7 is a schematic diagram of the planar structure of a second pn-type charge generation layer provided by an embodiment of the present invention;

[0055] Figure 8 is a schematic flow chart of a method for preparing a QLED device provided by an embodiment of the present invention;

[0056] Fig. 9 is a schematic flow chart of a method for preparing a first pn-type charge generation layer provided by one embodiment of the present invention;

[0057] Fig.10 It is a schematic diagram of the three-dimensional structure of a QLED display device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0058] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0059] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot 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 of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0060] In the description of the present invention, it should be understood that the term "including" means "including but not limited to".

[0061] The embodiments of the present invention provide a QLED device and a method for preparing the same. The embodiments are described in detail below. It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments.

[0062] First, see Figures 1 to 4 , an embodiment of the present invention provides a QLED device, the QLED device comprising: a first electrode 12, a first pn-type charge generation layer 13, a quantum dot light-emitting layer 14, a second pn-type charge generation layer 15, and a second electrode 16, which are stacked in sequence;

[0063] The first pn-type charge generation layer 13 includes a plurality of first p-type charge generation units 132 and a plurality of first n-type charge generation units 131, and the first p-type charge generation units 132 and the first n-type charge generation units 131 are in the same layer and are alternately arranged along the first direction;

[0064] The second pn-type charge generation layer 15 includes a plurality of second p-type charge generation units 151 and a plurality of second n-type charge generation units 152, and the second p-type charge generation units 151 and the second n-type charge generation units 152 are in the same layer and are alternately arranged along the first direction;

[0065] The orthographic projection of the first p-type charge generating unit 132 on the QLED device plane and the orthographic projection of the second n-type charge generating unit 152 on the QLED device plane have at least one overlapping area, and the orthographic projection of the second p-type charge generating unit 151 on the QLED device plane and the orthographic projection of the first n-type charge generating unit 131 on the QLED device plane have at least one overlapping area.

[0066] The embodiment of the present invention provides a QLED device, by placing a first p-type charge generating unit and a first n-type charge generating unit in the same layer and alternately arranged along a first direction, and placing a second p-type charge generating unit and a second n-type charge generating unit in the same layer and alternately arranged along a first direction, it is possible to achieve that both electrons and holes can be transmitted in the same layer, and the QLED device can be alternately lit under positive and negative bias voltages. Under high-frequency alternating current, due to the perception latency of the human eye, the QLED device can produce a stable lighting visual effect.

[0067] Optionally, the QLED device further includes: a rigid or flexible substrate 11 located on the first electrode 12 away from the first pn-type charge generating layer 13. Specifically, the material forming the substrate 11 includes but is not limited to one or more of glass, polyacetamide (PI), polyester (PET), polyvinyl alcohol (PVA), polyethylene naphthalate (PEN), etc.

[0068] Specifically, the QLED device further includes: a pixel defining structure, which is disposed between the first p-type charge generating unit 132 and the first n-type charge generating unit 131; and between the second p-type charge generating unit 151 and the second n-type charge generating unit 152, for isolation to prevent display problems. In one embodiment, the pixel defining structure material is an insulating material.

[0069] For example, Figure 5 As shown, Figure 5 This embodiment shows Figure 1 The QLED device shown is a schematic diagram of a cross-sectional structure obtained by cutting along the PP direction, wherein the QLED device includes a substrate 11, a first electrode 12, a first pn-type charge generation layer 13, a quantum dot light-emitting layer 14, a second pn-type charge generation layer 15, and a second electrode 16 which are stacked in sequence; the first pn-type charge generation layer 13 includes a first p-type charge generation unit 132 and a first n-type charge generation unit 131, and the second pn-type charge generation layer 15 includes a second p-type charge generation unit 151 and a second n-type charge generation unit 152; wherein the first p-type charge generation unit 132 and the first n-type charge generation unit 131, as well as the second p-type charge generation unit 151 and the second n-type charge generation unit 152 are separated by a pixel defining structure 19.

[0070] Optionally, the quantum dot light-emitting layer 14 includes quantum dots, and the material forming the quantum dots includes CdSe / ZnS, CdZnS / ZnS, CdxZn 1-x Sey 1-y / ZnS, PbSe / PbS, PbSe / CdS, PbSe / ZnS, MAPbX3, CsPbX3 or one or more of Cu-In-S.

[0071] Optionally, the material of the first electrode 12 may be indium tin oxide (ITO) conductive film, silver (Ag) nanowires or other conductive oxides; the material of the second electrode 16 includes but is not limited to gold (Au), silver (Ag), copper (Cu), aluminum (Al) and their alloys and laminated structures.

[0072] Based on the above embodiments, in one embodiment of the present invention, the QLED device further includes a first dielectric layer 18 located between the first electrode 12 and the first pn-type charge generation layer 13 , and / or a second dielectric layer 17 located between the second electrode 16 and the second pn-type charge generation layer 15 .

[0073] Optionally, the materials of the first dielectric layer 18 and the second dielectric layer 17 include, but are not limited to, one or more of organic polymer materials and metal oxides. Specifically, the organic polymer material includes, but is not limited to, one or more of polyvinyl pyrrolidone (PVP) and polymethyl methacrylate (PMMA); the metal oxide includes, but is not limited to, one or more of silicon dioxide (SiO2), aluminum oxide (Al2O3), hafnium oxide (HfO2), and zirconium oxide (ZrO2).

[0074] Optionally, the thickness of the first dielectric layer 18 and the second dielectric layer 17 is 10 nanometers to 50 microns, for example: 10 nanometers, 20 nanometers, 30 nanometers, 40 nanometers, 50 nanometers, 100 nanometers, 500 nanometers, 1 micron, 10 microns, 20 microns, 30 microns, 40 microns and 50 microns, or other unlisted values ​​between 10 nanometers and 50 microns.

[0075] Optionally, the materials of the first p-type charge generating unit 132 and the second p-type charge generating unit 151 include PEDOT:PSS (poly 3,4-ethylenedioxythiophene / polystyrene sulfonate), TFB (poly (9,9-dioctylfluorene-CO-N-(4-butylphenyl) diphenylamine)), poly-TPD (poly [bis (4-phenyl) (4-butylphenyl) amine]), PVK (poly (9-vinyl carbazole)) or PEDOT (poly 3,4-ethylenedioxythiophene) material, or molybdenum oxide (MoO3) material doped with one or more of copper (Cu), iron (Fe), aluminum (Al), and nickel (Ni). It can be understood that the above is only an example, and the materials of the first p-type charge generating unit 132 and the second p-type charge generating unit 151 may also include other materials, for example: NiO (nickel oxide), WO3 (tungsten trioxide), V2O5 (vanadium pentoxide) and other materials doped with one or more of copper, iron, aluminum, and nickel. In a specific embodiment, the materials of the first p-type charge generating unit 132 and the second p-type charge generating unit 151 are composed of PEDOT:PSS, TFB, poly-TPD, PVK or PEDOT materials, or molybdenum oxide materials doped with one or more of copper, iron, aluminum, and nickel.

[0076] Optionally, the materials of the first n-type charge generating unit 131 and the second n-type charge generating unit 152 include zinc oxide (ZnO) nanoparticles, or zinc oxide (ZnO) nanoparticles doped with one or more of aluminum (Al), lithium (Li), lanthanum (La), indium (In), and magnesium (Mg). It can be understood that the above is only an example, and the materials of the first n-type charge generating unit 131 and the second n-type charge generating unit 152 can also include other materials, such as TiO2 (titanium dioxide) or OXD-7 doped with one or more of aluminum, lithium, lanthanum, indium, and magnesium. In a specific embodiment, the materials of the first n-type charge generating unit 131 and the second n-type charge generating unit 152 are composed of zinc oxide nanoparticles, or zinc oxide nanoparticles doped with one or more of aluminum, lithium, lanthanum, indium, and magnesium.

[0077] Optionally, the first p-type charge generating unit 132 has the same thickness as the first n-type charge generating unit 131; the second p-type charge generating unit 151 has the same thickness as the second n-type charge generating unit 152. In a specific embodiment, the first p-type charge generating unit 132, the first n-type charge generating unit 131, the second p-type charge generating unit 151, and the second n-type charge generating unit 152 have the same thickness.

[0078] Optionally, the first p-type charge generating unit 132 includes a plurality of first p-type charge generating subunits arranged adjacent to each other along the second direction, the first n-type charge generating unit 131 includes a plurality of first n-type charge generating subunits arranged adjacent to each other along the second direction; and the second p-type charge generating unit 151 includes a plurality of second p-type charge generating subunits arranged adjacent to each other along the second direction, and the second n-type charge generating unit 152 includes a plurality of second n-type charge generating subunits arranged adjacent to each other along the second direction. In a specific embodiment, the first direction is perpendicular to the second direction.

[0079] Figure 6 A schematic top view of the first pn-type charge generation layer 13 in the plane direction of the QLED device is shown. Figure 7 FIG. 4 shows a schematic top view of the second pn-type charge generation layer 15 in the plane direction of the QLED device. Figure 6 and Figure 7As shown, the first p-type charge generating unit includes a plurality of first p-type charge generating sub-units 132a adjacently arranged along the second direction, and the first n-type charge generating unit includes a plurality of first n-type charge generating sub-units 131a adjacently arranged along the second direction, so that the first p-type charge generating unit and the first n-type charge generating unit are both in the shape of long strips as a whole, and are alternately arranged in the same layer along the first direction; the second p-type charge generating unit includes a plurality of second p-type charge generating sub-units 151a adjacently arranged along the second direction, and the second n-type charge generating unit includes a plurality of second n-type charge generating sub-units 152b adjacently arranged along the second direction, so that the second p-type charge generating unit and the second n-type charge generating unit are both in the shape of long strips as a whole, and are alternately arranged in the same layer along the first direction.

[0080] It should be noted that "adjacent" in the above embodiments does not mean absolutely adjacent, that is: other structures may also be set between the multiple first p-type charge generating sub-units 132a, between the multiple first n-type charge generating sub-units 131a, between the multiple second p-type charge generating sub-units 151a, and between the multiple second n-type charge generating sub-units 152b. For example: in some embodiments, the multiple first p-type charge generating sub-units 132a are separated by a pixel defining structure, the multiple first n-type charge generating sub-units 131a are separated by a pixel defining structure, the multiple second p-type charge generating sub-units 151a are separated by a pixel defining structure, and the multiple second n-type charge generating sub-units 152b are separated by a pixel defining structure.

[0081] It should be noted that the above embodiments are only examples. In other embodiments of the present invention, the shapes of the first p-type charge generating unit 132, the first n-type charge generating unit 131, the second p-type charge generating unit 151 and the second n-type charge generating unit 152 may also be other shapes, as long as the shapes of the first p-type charge generating unit 132 and the second n-type charge generating unit 152 can be arranged correspondingly, and the shapes of the second p-type charge generating unit 151 and the first n-type charge generating unit 131 can be arranged correspondingly, and the specific shapes are not limited here.

[0082] It should be noted that the present invention does not limit whether the widths of the rectangular strips of the first p-type charge generating unit 132, the first n-type charge generating unit 131, the second p-type charge generating unit 151 and the second n-type charge generating unit 152 are consistent. The widths of the plurality of first p-type charge generating units 132 and / or the first n-type charge generating units 131 may be the same or different; the widths of the plurality of second p-type charge generating units 151 and / or the second n-type charge generating units 152 may be the same or different.

[0083] Optionally, the first p-type charge generating units 132 and the first n-type charge generating units 131 are arranged in parallel and alternately adjacent to each other, and the second p-type charge generating units 151 and the second n-type charge generating units 152 are arranged in parallel and alternately adjacent to each other.

[0084] Optionally, the thickness of the first pn-type charge generation layer 13 and the second pn-type charge generation layer 15 is 5 nm to 50 nm, for example, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm and 50 nm, or other unlisted values ​​between 5 nm and 50 nm.

[0085] In a specific embodiment, the orthographic projection of the first p-type charge generating unit 132 on the QLED device plane coincides with the orthographic projection of the second n-type charge generating unit 152 on the QLED device plane, and the orthographic projection of the second p-type charge generating unit 151 on the QLED device plane coincides with the orthographic projection of the first n-type charge generating unit 131 on the QLED device plane.

[0086] For example, the orthographic projection area of ​​the first p-type charge generating unit 132 on the plane of the QLED device is equal to the orthographic projection area of ​​the second n-type charge generating unit 152 on the plane of the QLED device, and the two completely overlap along the projection direction; the orthographic projection area of ​​the second p-type charge generating unit 151 on the plane of the QLED device is equal to the orthographic projection area of ​​the first n-type charge generating unit 131 on the plane of the QLED device, and the two completely overlap along the projection direction. Under such a structure, the visual effect of the QLED device when lit is better.

[0087] In another specific embodiment, the orthographic projection area of ​​the first p-type charge generating unit 132 on the plane of the QLED device is not equal to the orthographic projection area of ​​the second n-type charge generating unit 152 on the plane of the QLED device, and the two do not completely overlap along the projection direction; the orthographic projection area of ​​the second p-type charge generating unit 151 on the plane of the QLED device is not equal to the orthographic projection area of ​​the first n-type charge generating unit 131 on the plane of the QLED device, and the two do not completely overlap along the projection direction. Because there is a partial correspondence between the first p-type charge generating unit 132 and the second n-type charge generating unit 152, and between the second p-type charge generating unit 151 and the first n-type charge generating unit 131, they can still be alternately lit under positive and negative bias voltages, so the QLED device can still produce a stable lighting visual effect.

[0088] Optionally, in the QLED device provided in an embodiment of the present invention, the frequency range of the AC driving signal during the driving process is 1 Hz to 15 MHz, and the waveform of the AC driving signal includes a sine wave, a triangle wave or a square wave.

[0089] In a second aspect, based on the same inventive concept of the above embodiments, the present invention further provides a method for preparing a QLED device, comprising:

[0090] A first electrode 12, a first pn-type charge generation layer 13, a quantum dot light-emitting layer 14, a second pn-type charge generation layer 15 and a second electrode 16 are sequentially stacked to form;

[0091] The first pn-type charge generation layer 13 includes a plurality of first p-type charge generation units 132 and a plurality of first n-type charge generation units 131, and the first p-type charge generation units 132 and the first n-type charge generation units 131 are in the same layer and are alternately arranged along the first direction;

[0092] The second pn-type charge generation layer 15 includes a plurality of second p-type charge generation units 151 and a plurality of second n-type charge generation units 152, and the second p-type charge generation units 151 and the second n-type charge generation units 152 are in the same layer and are alternately arranged along the first direction;

[0093] The orthographic projection of the first p-type charge generating unit 132 on the QLED device plane and the orthographic projection of the second n-type charge generating unit 152 on the QLED device plane have at least one overlapping area, and the orthographic projection of the second p-type charge generating unit 151 on the QLED device plane and the orthographic projection of the first n-type charge generating unit 131 on the QLED device plane have at least one overlapping area.

[0094] like Figure 8 As shown, Figure 8 It is a flow chart of a method for preparing a QLED device provided by an embodiment of the present invention, wherein the method for preparing the QLED device comprises: S1. forming a first electrode; S2. forming a first pn-type charge generation layer; S3. forming a quantum dot light-emitting layer; S4. forming a second pn-type charge generation layer; and S5. forming a second electrode 16.

[0095] Thus, the method for preparing a QLED device provided in an embodiment of the present invention can provide a QLED device that is AC driven and has stable light emission, high light emission efficiency, and high brightness; moreover, the method provided in an embodiment of the present invention does not require a complex film structure, nor does it require a complex current conversion device, thereby reducing the complexity of system integration, and can significantly reduce production costs for large-scale production; in addition, both the pn-type charge generation layer and the light-emitting layer can be prepared by inkjet printing, which is simple to operate and can also significantly reduce production costs for large-scale production.

[0096] In the embodiment of the present invention, the method for forming each functional layer such as the first pn-type charge generation layer 13, the quantum dot light-emitting layer 14 and the second pn-type charge generation layer 15 can be implemented by a method known in the art, such as a solution method, which can include: spin coating, printing, inkjet printing, scraping, printing, dip-coating, immersion, spraying, roll coating, casting, slit coating, strip coating. As an exemplary embodiment, each functional layer is prepared by inkjet printing, which can greatly reduce production costs and is used for large-scale production.

[0097] Specifically, Fig. 9 As shown, Fig. 9 A schematic flow chart of an embodiment of a method for forming a first pn-type charge generation layer using an inkjet printing method is shown. The structure of the first pn-type charge generation layer formed is finally as follows: Figure 6 As shown, the method specifically comprises the following steps:

[0098] S11. Using an inkjet printing method, inkjet printing a first p-type charge generating unit on the first electrode in alternate lines; and

[0099] S21. In the row adjacent to the first p-type charge generating unit, inkjet print the first n-type charge generating unit in alternate rows.

[0100] In some embodiments, different from the above embodiments, the printing order between the first p-type charge generating unit and the first n-type charge generating unit can be swapped, which specifically includes the following steps:

[0101] S12. Using an inkjet printing method, inkjet printing a first n-type charge generating unit on top of the first electrode in alternate lines; and

[0102] S22. In the row adjacent to the first n-type charge generating unit, inkjet print the first p-type charge generating unit in alternate rows.

[0103] Specifically, the formation of the second pn-type charge generation layer 15 includes the following steps:

[0104] S13. Using an inkjet printing method, interlaced inkjet printing a second p-type charge generating unit above the quantum dot light-emitting layer; and

[0105] S23. In the row adjacent to the second p-type charge generating unit, inkjet print the second n-type charge generating unit in alternate rows.

[0106] In some embodiments, different from the above embodiments, the printing order between the second p-type charge generating unit and the second n-type charge generating unit can be exchanged, which specifically includes the following steps:

[0107] S14. Using an inkjet printing method, inkjet printing a second n-type charge generating unit on top of the quantum dot light-emitting layer in alternate lines; and

[0108] S24. In the row adjacent to the second n-type charge generating unit, inkjet print the second p-type charge generating unit in alternate rows.

[0109] Optionally, the first pn-type charge generation layer 13 and the second pn-type charge generation layer 15 are formed by inkjet printing.

[0110] Optionally, before forming the first pn-type charge generation layer 13 , the method further includes: forming a first dielectric layer 18 on the first electrode 12 ; and / or before forming the second electrode 16 , the method further includes: forming a second dielectric layer 17 on the second pn-type charge generation layer 15 .

[0111] Optionally, the first electrode 12 is formed by magnetron sputtering. Specifically, the material of the first electrode 12 is ITO.

[0112] Optionally, the second electrode 16 is formed by vacuum evaporation. Specifically, the material of the second electrode 16 is Ag.

[0113] On the third aspect, based on the same inventive concept of the above embodiments, the embodiments of the present invention also provide a QLED display device, including: the QLED device provided by any of the above embodiments, or the QLED device made by the preparation method of any of the above embodiments, whose structure, implementation principle and effect are similar and will not be repeated here.

[0114] For example, Fig.10 As shown, Fig.10 A schematic diagram of the three-dimensional structure of a QLED display device is shown, wherein the QLED device includes a substrate 11, a first electrode 12, a first pn-type charge generation layer 13, a quantum dot light-emitting layer 14, a second pn-type charge generation layer 15 and a second electrode 16 which are stacked in sequence.

[0115] Optionally, the QLED display device may be: a lighting fixture and a backlight source, or any product or component with a display function, such as a mobile phone, a tablet computer, a television, a monitor, a laptop computer, a digital photo frame, and a navigator.

[0116] It should be noted that the drawings of the embodiments of the present invention only involve the structures involved in the embodiments of the present invention, and other structures may refer to the usual designs.

[0117] In addition, in order to better understand the present invention, the present invention also provides the following specific embodiments.

[0118] Example 1

[0119] like Figure 2 As shown, Embodiment 1 provides a QLED device, comprising: a substrate 11, a first electrode 12, a first pn-type charge generation layer 13, a quantum dot light-emitting layer 14, a second pn-type charge generation layer 15, and a second electrode 16 stacked in sequence. The first pn-type charge generation layer 13 comprises a plurality of first p-type charge generation units 132 and first n-type charge generation units 131 arranged alternately adjacent to each other in the same layer. The second pn-type charge generation layer 15 comprises a plurality of second p-type charge generation units 151 and second n-type charge generation units 152 arranged alternately adjacent to each other in the same layer.

[0120] The substrate 11 is a glass substrate, and the first electrode 12 is an ITO film deposited by magnetron sputtering. The first pn-type charge generation layer 13, the quantum dot light-emitting layer 14, and the second pn-type charge generation layer 15 are all prepared by inkjet printing. The material of the first p-type charge generation unit 132 and the second p-type charge generation unit 151 is PEDOT:PSS, and its thickness is 5 nanometers to 50 nanometers; the material of the first n-type charge generation unit 131 and the second n-type charge generation unit 152 is ZnO nanoparticles, and its thickness is 5 nanometers to 50 nanometers. The material of the quantum dot light-emitting layer 14 is CdSe, and its thickness is 5 nanometers to 50 nanometers; the second electrode 16 is an Ag material using vacuum evaporation, and its thickness is 200 nanometers.

[0121] The first p-type charge generating unit 132 is disposed correspondingly to the second n-type charge generating unit 152 , and the second p-type charge generating unit 151 is disposed correspondingly to the first n-type charge generating unit 131 .

[0122] The QLED device provided in this embodiment has an AC driving signal with a frequency range of 1 Hz to 15 MHz during the driving process, and the waveform of the AC driving signal includes a sine wave, a triangle wave or a square wave. The device can be used as a lighting fixture, a display or a backlight source.

[0123] Example 2

[0124] like Figure 3 As shown, Embodiment 2 provides a QLED device, comprising: a substrate 11, a first electrode 12, a first pn-type charge generation layer 13, a quantum dot light-emitting layer 14, a second pn-type charge generation layer 15, a second dielectric layer 17, and a second electrode 16 stacked in sequence. The first pn-type charge generation layer 13 comprises a plurality of first p-type charge generation units 132 and first n-type charge generation units 131 arranged alternately adjacent to each other in the same layer, and the second pn-type charge generation layer 15 comprises a plurality of second p-type charge generation units 151 and second n-type charge generation units 152 arranged alternately adjacent to each other in the same layer.

[0125] In this embodiment, the substrate 11 is a glass substrate, and the first electrode 12 is an ITO film deposited by magnetron sputtering. The first pn-type charge generation layer 13, the quantum dot light-emitting layer 14, and the second pn-type charge generation layer 15 are all prepared by inkjet printing. The material of the first p-type charge generation unit 132 and the second p-type charge generation unit 151 is PEDOT:PSS, and its thickness is 5 nanometers to 50 nanometers; the material of the first n-type charge generation unit 131 and the second n-type charge generation unit 152 is ZnO nanoparticles, and its thickness is 5 nanometers to 50 nanometers. The material of the quantum dot light-emitting layer 14 is CdSe, and its thickness is 5 nanometers to 50 nanometers. The material of the second dielectric layer 17 is Al2O3, and its thickness is 10 nanometers to 50 micrometers. The second electrode 16 is an Ag material using vacuum evaporation, and its thickness is 200 nanometers.

[0126] The first p-type charge generating unit 132 is disposed correspondingly to the second n-type charge generating unit 152 , and the second p-type charge generating unit 151 is disposed correspondingly to the first n-type charge generating unit 131 .

[0127] The QLED device provided in this embodiment has an AC driving signal with a frequency range of 1 Hz to 15 MHZ during the driving process, and the waveform of the AC driving signal includes a sine wave, a triangle wave or a square wave. The device can be used as a lighting fixture, a display or a backlight source.

[0128] Example 3

[0129] like Figure 4As shown, Embodiment 3 provides a QLED device, comprising: a substrate 11, a first electrode 12, a first dielectric layer 18, a first pn-type charge generation layer 13, a quantum dot light-emitting layer 14, a second pn-type charge generation layer 15, a second dielectric layer 17, and a second electrode 16 stacked in sequence. The first pn-type charge generation layer 13 comprises a plurality of first p-type charge generation units 132 and first n-type charge generation units 131 arranged alternately adjacent to each other in the same layer, and the second pn-type charge generation layer 15 comprises a plurality of second p-type charge generation units 151 and second n-type charge generation units 152 arranged alternately adjacent to each other in the same layer.

[0130] In this embodiment, the substrate 11 is a glass substrate, and the first electrode 12 is an ITO film deposited by magnetron sputtering. The first pn-type charge generation layer 13, the quantum dot light-emitting layer 14, and the second pn-type charge generation layer 15 are all prepared by inkjet printing. The material of the first p-type charge generation unit 132 and the second p-type charge generation unit 151 is PEDOT:PSS, and its thickness is 5 nanometers to 50 nanometers; the material of the first n-type charge generation unit 131 and the second n-type charge generation unit 152 is ZnO nanoparticles, and its thickness is 5 nanometers to 50 nanometers. The material of the quantum dot light-emitting layer 14 is CdSe, and its thickness is 5 nanometers to 50 nanometers. The material of the first dielectric layer 18 and the second dielectric layer 17 is Al2O3, and its thickness is 10 nanometers to 50 micrometers. The second electrode 16 is an Ag material using vacuum evaporation, and its thickness is 200 nanometers.

[0131] The first p-type charge generating unit 132 is disposed correspondingly to the second n-type charge generating unit 152 , and the second p-type charge generating unit 151 is disposed correspondingly to the first n-type charge generating unit 131 .

[0132] The QLED device provided in this embodiment has an AC driving signal with a frequency range of 1 Hz to 15 MHz during the driving process, and the waveform of the AC driving signal includes a sine wave, a triangle wave or a square wave. The device can be used as a lighting fixture, a display or a backlight source.

[0133] Example 4

[0134] Example 4 provides a method for preparing a QLED device, and the preparation process is as follows:

[0135] (1) Provide a substrate and etch the ITO electrode.

[0136] (2) Spin-coating a hydrophobic photoresist on the substrate, and developing and exposing the photoresist using a mask of a desired size to obtain a base substrate with a pixel defining layer bank, wherein the hydrophobic photoresist material used to make the pixel defining layer bank can be a material such as polyimide, or a compound containing halogens such as fluorine and chlorine.

[0137] (3) The ITO substrate with the bank pattern was placed on a dedicated film washing rack for ultrasonic cleaning and baked at 230°C for 30 minutes.

[0138] (4) The p-type charge generation layer material ink and the n-type charge generation layer material ink of the first pn-type charge generation layer are filtered through a 0.22 μm filter head respectively and injected into two ink cartridges for inkjet printing. By adjusting the printing voltage, air pressure, waveform and other parameters, stable ejection of droplets is adjusted.

[0139] (5) Placing the substrate on the substrate platform of the printer, adjusting the rotation angle of the inkjet print head and the height of the substrate, aligning the mark of the substrate, and sequentially inkjet-printing the strip-shaped p-type charge generation layer of the first pn-type charge generation layer at a predetermined position in an interlaced manner, so that the ink droplets of the inkjet printing fall into the bank of the pixel defining layer, and inkjet-printing the strip-shaped n-type charge generation layer in an interlaced manner at the adjacent strips of the strip-shaped p-type charge generation layer, wherein the inkjet printing process is performed in a glove box filled with nitrogen.

[0140] (6) The luminescent material ink is filtered through a 0.22 μm filter head and injected into an ink cartridge for inkjet printing. After the stable ejection of droplets is adjusted by adjusting the printing voltage, air pressure, waveform and other parameters, the mark of the substrate is aligned and inkjet printing is performed so that the ink droplets of inkjet printing fall into the bank of the pixel definition layer. The luminescent layer ink material is printed line by line, and the inkjet printing process is carried out in a glove box filled with nitrogen.

[0141] (7) The p-type charge generation layer material ink and the n-type charge generation layer material ink of the second pn-type charge generation layer are filtered through a 0.22 μm filter head respectively and injected into two ink cartridges for inkjet printing. By adjusting the printing voltage, air pressure, waveform and other parameters, stable spraying of droplets is achieved.

[0142] (8) Placing the substrate on the substrate platform of the printer, adjusting the rotation angle of the inkjet print head and the height of the substrate, aligning the mark of the substrate, and sequentially inkjet-printing the strip-shaped n-type charge generation layer of the second pn-type charge generation layer at a predetermined position in alternating lines, so that the inkjet-printed ink droplets fall into the bank of the pixel defining layer, and inkjet-printing the strip-shaped p-type charge generation layer in alternating lines at adjacent strips of the strip-shaped n-type charge generation layer, wherein the inkjet printing process is performed in a glove box filled with nitrogen.

[0143] (9) Place the printed substrate into the vacuum evaporation equipment with the light-emitting layer facing downward. Elevate the vacuum to 3×10 - 5 Pa, the Ag electrode was deposited.

[0144] (10) Encapsulate the evaporated substrate. Paste a drying sheet in the light-emitting area of ​​the substrate, apply encapsulation glue around the concave glass encapsulation sheet, and then cover it on the substrate and irradiate it with ultraviolet light for 30 minutes to completely cure the encapsulation glue. Finally, take the QLED device out of the glove box for photoelectric performance testing.

[0145] In summary, the present invention provides a QLED device and a preparation method thereof. The QLED device can realize that both electrons and holes can be transmitted in the same layer by placing the first p-type charge generating unit and the first n-type charge generating unit in the same layer and alternately arranged along the first direction, and the second p-type charge generating unit and the second n-type charge generating unit in the same layer and alternately arranged along the first direction, and can be alternately lit under positive and negative bias voltages. Under high-frequency alternating current, due to the perception latency of the human eye, the QLED device can produce a stable lighting visual effect; the preparation method of the QLED device can provide a QLED device that is AC-driven and has stable light emission, high light emission efficiency, and high brightness; and the preparation method of the OLED does not require a complex film layer structure or a complex current conversion device, thereby reducing the complexity of system integration, greatly reducing production costs, and being used for large-scale production; in addition, both the pn-type charge generating layer and the light-emitting layer can be prepared by inkjet printing, which is simple to operate and can also greatly reduce production costs, and be used for large-scale production.

[0146] A QLED device and a preparation method thereof provided in an embodiment of the present invention are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A QLED device, characterized in that: include: A first electrode, a first pn-type charge generation layer, a quantum dot light-emitting layer, a second pn-type charge generation layer, and a second electrode are sequentially stacked; The first pn-type charge generation layer includes a plurality of first p-type charge generation units and a plurality of first n-type charge generation units, and the first p-type charge generation units and the first n-type charge generation units are in the same layer and are alternately arranged along a first direction; The second pn-type charge generation layer includes a plurality of second p-type charge generation units and a plurality of second n-type charge generation units, and the second p-type charge generation units and the second n-type charge generation units are in the same layer and are alternately arranged along the first direction; The orthographic projection of the first p-type charge generating unit on the QLED device plane and the orthographic projection of the second n-type charge generating unit on the QLED device plane have at least one overlapping area, and the orthographic projection of the second p-type charge generating unit on the QLED device plane and the orthographic projection of the first n-type charge generating unit on the QLED device plane have at least one overlapping area.

2. The QLED device according to claim 1, characterized in that The QLED device further includes a first dielectric layer located between the first electrode and the first pn-type charge generation layer, and / or a second dielectric layer located between the second electrode and the second pn-type charge generation layer.

3. The QLED device according to claim 2, characterized in that The material of the first dielectric layer includes one or more of an organic polymer material and a metal oxide, and the material of the second dielectric layer includes one or more of an organic polymer material and a metal oxide.

4. The QLED device according to claim 1, characterized in that The first p-type charge generation unit has the same thickness as the first n-type charge generation unit, and / or the second p-type charge generation unit has the same thickness as the second n-type charge generation unit.

5. The QLED device according to claim 1, characterized in that The orthographic projection of the first p-type charge generating unit on the QLED device plane coincides with the orthographic projection of the second n-type charge generating unit on the QLED device plane, and the orthographic projection of the second p-type charge generating unit on the QLED device plane coincides with the orthographic projection of the first n-type charge generating unit on the QLED device plane.

6. The QLED device according to claim 1, characterized in that The material of the first p-type charge generation unit includes PEDOT:PSS, TFB, poly-TPD, PVK or PEDOT material, or molybdenum oxide material doped with one or more of copper, iron, aluminum, and nickel; the material of the second p-type charge generation unit includes PEDOT:PSS, TFB, poly-TPD, PVK or PEDOT material, or molybdenum oxide material doped with one or more of copper, iron, aluminum, and nickel; and / or, The material of the first n-type charge generation unit includes zinc oxide nanoparticles, or zinc oxide nanoparticles doped with one or more of aluminum, lithium, lanthanum, indium, and magnesium; the material of the second n-type charge generation unit includes zinc oxide nanoparticles, or zinc oxide nanoparticles doped with one or more of aluminum, lithium, lanthanum, indium, and magnesium.

7. The QLED device according to claim 1, characterized in that The material of the first p-type charge generation unit is composed of PEDOT:PSS, TFB, poly-TPD, PVK or PEDOT material, or molybdenum oxide material doped with one or more of copper, iron, aluminum and nickel, and the material of the second p-type charge generation unit is composed of PEDOT:PSS, TFB, poly-TPD, PVK or PEDOT material, or molybdenum oxide material doped with one or more of copper, iron, aluminum and nickel; and / or, The material of the first n-type charge generation unit consists of zinc oxide nanoparticles, or zinc oxide nanoparticles doped with one or more of aluminum, lithium, lanthanum, indium, and magnesium; the material of the second n-type charge generation unit consists of zinc oxide nanoparticles, or zinc oxide nanoparticles doped with one or more of aluminum, lithium, lanthanum, indium, and magnesium.

8. The QLED device according to claim 1, characterized in that The thickness of the first pn-type charge generation layer is 5 nanometers to 50 nanometers, and the thickness of the second pn-type charge generation layer is 5 nanometers to 50 nanometers.

9. The QLED device according to claim 1, characterized in that The QLED device further includes a pixel defining structure disposed between the first p-type charge generating unit and the first n-type charge generating unit, and between the second p-type charge generating unit and the second n-type charge generating unit.

10. The QLED device according to claim 1, characterized in that The first p-type charge generating unit includes a plurality of first p-type charge generating sub-units adjacently arranged along the second direction, and the first n-type charge generating unit includes a plurality of first n-type charge generating sub-units adjacently arranged along the second direction; and the second p-type charge generating unit includes a plurality of second p-type charge generating sub-units adjacently arranged along the second direction, and the second n-type charge generating unit includes a plurality of second n-type charge generating sub-units adjacently arranged along the second direction.

11. A method for preparing a QLED device, characterized in that: include: A first electrode, a first pn-type charge generation layer, a quantum dot light-emitting layer, a second pn-type charge generation layer and a second electrode are sequentially stacked to form; The first pn-type charge generation layer includes a plurality of first p-type charge generation units and a plurality of first n-type charge generation units, and the first p-type charge generation units and the first n-type charge generation units are in the same layer and are alternately arranged along a first direction; The second pn-type charge generation layer includes a plurality of second p-type charge generation units and a plurality of second n-type charge generation units, and the second p-type charge generation units and the second n-type charge generation units are in the same layer and are alternately arranged along the first direction; The orthographic projection of the first p-type charge generating unit on the QLED device plane and the orthographic projection of the second n-type charge generating unit on the QLED device plane have at least one overlapping area, and the orthographic projection of the second p-type charge generating unit on the QLED device plane and the orthographic projection of the first n-type charge generating unit on the QLED device plane have at least one overlapping area.

12. The method for preparing a QLED device according to claim 11, wherein: The method for forming the first pn-type charge generation layer comprises: By using a solution method, a first p-type charge generating unit is formed in alternate rows above the first electrode; a first n-type charge generating unit is formed in alternate rows at a row adjacent to the first p-type charge generating unit; or By using a solution method, first n-type charge generation units are formed in alternate rows above the first electrode; and first p-type charge generation units are formed in alternate rows at rows adjacent to the first n-type charge generation units.

13. The method for preparing a QLED device according to claim 11, wherein: The method for forming the second pn-type charge generation layer comprises: By using a solution method, second p-type charge generation units are formed in alternate rows above the quantum dot light-emitting layer; second n-type charge generation units are formed in alternate rows at the rows adjacent to the second p-type charge generation units; or By using a solution method, second n-type charge generation units are formed in alternate rows above the quantum dot light-emitting layer; and second p-type charge generation units are formed in alternate rows at rows adjacent to the second n-type charge generation units.

14. A QLED display device, characterized in that: A QLED device comprising any one of claims 1 to 10, or a QLED device prepared by the method described in any one of claims 11 to 13.

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