Display panel and display device

Abstract

The embodiment of the utility model provides a display panel and a display device, relates to the technical field of display, and is used for improving the luminous efficiency of the display panel. The display panel includes: a plurality of light emitting devices; the at least one light emitting device further includes at least one of a hole buffer layer, an electron buffer layer, a hole enhancement layer, and an electron enhancement layer; the hole buffer layer is located between the hole transport layer and the quantum dot light-emitting layer of the first light-emitting device emitting blue light, and the hole transport speed is reduced; the electron buffer layer is located between the quantum dot light-emitting layer and the electron transmission layer of the second light-emitting device emitting red light or green light, so that the transmission speed of electrons is reduced; the hole enhancement layer is located between the hole transmission layer and the quantum dot light-emitting layer of the second light-emitting device, and the hole transmission speed is increased; the electron enhancement layer is located between the quantum dot light-emitting layer and the electron transmission layer of the first light-emitting device, the transmission speed of electrons is increased, and the display panel is used for displaying images.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and more particularly to a display panel and display device. Background Technology

[0002] Quantum dots (QDs), as novel light-emitting materials, possess advantages such as high light purity, high quantum efficiency, tunable color emission, and long lifespan, making them a research hotspot for novel light-emitting diodes (LEDs). Therefore, quantum dot light-emitting diodes (QLEDs) using quantum dot materials as the light-emitting layer have become a major research direction for novel display devices. Utility Model Content

[0003] The purpose of the embodiments of this disclosure is to provide a display panel and a display device for promoting the balance of charge carrier transport in the light-emitting devices of the display panel and improving the luminous efficiency of the display panel.

[0004] On one hand, a display panel is provided. The display panel includes: a substrate and a plurality of light-emitting devices located on one side of the substrate; each of the plurality of light-emitting devices includes: an electrode disposed opposite to each other, and a hole transport layer, a quantum dot light-emitting layer and an electron transport layer disposed between the oppositely disposed electrodes and stacked sequentially; the plurality of light-emitting devices includes: a first light-emitting device and a second light-emitting device, the first light-emitting device being configured to emit blue light, and the second light-emitting device being configured to emit either red light or green light.

[0005] Wherein, at least one of the light-emitting devices further includes: an additional functional layer; the additional functional layer includes at least one of: a hole buffer layer, an electron buffer layer, a hole enhancement layer, and an electron enhancement layer.

[0006] The hole buffer layer is located between the hole transport layer and the quantum dot light-emitting layer of the first light-emitting device, and the hole buffer layer is configured to reduce the hole transport speed; the electron buffer layer is located between the quantum dot light-emitting layer and the electron transport layer of the second light-emitting device, and the electron buffer layer is configured to reduce the electron transport speed; the hole enhancement layer is located between the hole transport layer and the quantum dot light-emitting layer of the second light-emitting device, and the hole enhancement layer is configured to increase the hole transport speed; the electron enhancement layer is located between the quantum dot light-emitting layer and the electron transport layer of the first light-emitting device, and the electron enhancement layer is configured to increase the electron transport speed.

[0007] In the aforementioned display panel, the carrier transport balance of the light-emitting device is improved by adding additional functional layers. In the first light-emitting device, electron transport is slower than hole transport. A hole buffer layer is used to reduce the hole transport speed, and an electron enhancement layer is used to increase the electron transport speed, allowing electrons and holes to recombine in the quantum dot light-emitting layer, thereby improving the luminous efficiency of the light-emitting device. In the second light-emitting device, electron transport is faster than hole transport. An electron buffer layer is used to reduce the electron transport speed, and a hole enhancement layer is used to increase the hole transport speed, allowing electrons and holes to recombine in the quantum dot light-emitting layer, thereby improving the luminous efficiency of the light-emitting device.

[0008] In some embodiments, the hole buffer layer material includes at least one of an insulating material, an interfacial dipole material, and an electron transport material.

[0009] In some embodiments, the material of the hole buffer layer includes at least one of: polymethyl methacrylate, aluminum oxide, polyvinylpyrrolidone, poly[(9,9-di(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-di-n-octylfluorenyl-2,7-diyl), polyethoxyethyleneimine, poly[(9,9-di(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-di-n-octylfluorenyl-2,7-diyl)-bromo] and naphthalimide.

[0010] In some embodiments, the material of the hole buffer layer includes: a first crosslinking material, which is formed by crosslinking a first material with a photosensitive crosslinking agent through a hydrocarbon insertion reaction; the first material includes at least one of polymethyl methacrylate, poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-di-n-octylfluorenyl-2,7-diyl) and polyvinylpyrrolidone.

[0011] In some embodiments, the photosensitive crosslinking agent includes at least one of carbene precursors, azide derivatives, and photosensitive metal complexes.

[0012] In some embodiments, the photosensitive crosslinking agent includes at least one of diazacyclopropylene, triazaene, sulfonyl azide, phenyl azide, perfluoroalkyl azide, bipyridine ruthenium, and iridium complexes.

[0013] In some embodiments, the thickness of the hole buffer layer ranges from 5 nm to 8 nm.

[0014] In some embodiments, the material of the electron buffer layer includes: a second crosslinking material, which is formed by crosslinking a second material with a photosensitive crosslinking agent through a hydrocarbon intercalation reaction; the second material includes: an insulating organic material with a carrier mobility less than or equal to 10. -6 cm 3 At least one of the following: organic materials with an energy level of / v·s and P-type semiconductor materials with an LUMO level greater than or equal to -2.6eV.

[0015] In some embodiments, the second material comprises at least one of polymethyl methacrylate, polyvinylpyrrolidone, poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4′-(N-(4-sec-butylphenyl)diphenylamine)] and poly(9,9-n-dioctyl-2,7-fluorene-alt-9-isooctyl-3,6-carbazole).

[0016] In some embodiments, the thickness of the electron buffer layer ranges from 5 nm to 8 nm.

[0017] In some embodiments, the material of the hole enhancement layer includes: a third crosslinking material, which is formed by crosslinking a third material with a photosensitive crosslinking agent through a hydrocarbon insertion reaction; the HOMO energy level range of the third material is -5.3 eV to -6.0 eV.

[0018] In some embodiments, the third material comprises at least one of: polyvinylcarbazole, 4,4,4,-tris(carbazole-9-yl)triphenylamine, N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine, and 4,4'-bis(N-carbazole)biphenyl.

[0019] In some embodiments, the thickness of the hole enhancement layer ranges from 8 nm to 12 nm.

[0020] In some embodiments, the material of the electron enhancement layer includes at least one of an interface dipole material and an electron transport material.

[0021] In some embodiments, the material of the electron enhancement layer includes: a fourth crosslinking material, which is formed by crosslinking a fourth material with a photosensitive crosslinking agent through a hydrocarbon insertion reaction; the fourth material includes at least one of poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-di-n-octylfluorenyl-2,7-diyl), poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-di-n-octylfluorenyl-2,7-diyl)-bromo] and polyethoxyethyleneimine.

[0022] In some embodiments, the thickness of the electron enhancement layer ranges from 3 nm to 5 nm.

[0023] In some embodiments, the surface of the electrode on the side of the first light-emitting device away from the substrate is not flush with the surface of the electrode on the side of the second light-emitting device away from the substrate.

[0024] In some embodiments, the distance between the surface of the electrode of the first light-emitting device on the side away from the substrate and the surface of the electrode of the second light-emitting device on the side away from the substrate in a first direction is in the range of 5 nm to 8 nm; wherein, the first direction is perpendicular to the substrate.

[0025] On the other hand, a method for fabricating a display panel is provided, the method comprising: forming a plurality of light-emitting devices on one side of a substrate, each of the plurality of light-emitting devices comprising: an electrode disposed opposite to each other, and a hole transport layer, a quantum dot light-emitting layer and an electron transport layer disposed between the oppositely disposed electrodes and stacked sequentially; the plurality of light-emitting devices comprising: a first light-emitting device and a second light-emitting device, the first light-emitting device being configured to emit blue light, and the second light-emitting device being configured to emit either red light or green light.

[0026] At least one of the light-emitting devices further includes: an additional functional layer; the additional functional layer includes at least one of a hole buffer layer, an electron buffer layer, a hole enhancement layer, and an electron enhancement layer. The hole buffer layer is located between the hole transport layer and the quantum dot light-emitting layer of the first light-emitting device, and is configured to reduce the hole transport speed; the electron buffer layer is located between the quantum dot light-emitting layer and the electron transport layer of the second light-emitting device, and is configured to reduce the electron transport speed; the hole enhancement layer is located between the hole transport layer and the quantum dot light-emitting layer of the second light-emitting device, and is configured to increase the hole transport speed; the electron enhancement layer is located between the quantum dot light-emitting layer and the electron transport layer of the first light-emitting device, and is configured to increase the electron transport speed.

[0027] In some embodiments, forming a plurality of light-emitting devices on one side of a substrate includes: forming the additional functional layer; forming the additional functional layer includes: forming an initial material layer, the initial material layer comprising a functional material and a photosensitive crosslinking agent, the functional material comprising any one of a first material, a second material, a third material, and a fourth material; exposing the initial material layer to form exposed and unexposed areas; and removing the unexposed area material from the initial material layer to obtain the additional functional layer.

[0028] The first material comprises at least one of polymethyl methacrylate, poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-di-n-octylfluorenyl-2,7-diyl)], and polyvinylpyrrolidone; the second material comprises an insulating organic material with a carrier mobility less than or equal to 10. -6 cm 3 The third material comprises at least one of the following: an organic material with an LUMO energy level greater than or equal to -2.6 eV and a P-type semiconductor material; the fourth material comprises at least one of the following: polyvinylcarbazole, 4,4,4,-tris(carbazole-9-yl)triphenylamine, N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine, and 4,4'-bis(N-carbazole)biphenyl; the fifth material comprises: poly[(9,9-di(3'-(N,N- At least one of (9,9-di-n-octylfluorenyl-2,7-diyl), poly[(9,9-di(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-di-n-octylfluorenyl-2,7-diyl)bromo] and polyethoxyethyleneimine; the photosensitive crosslinking agent comprises at least one of carbene precursors, azide derivatives and photosensitive metal complexes.

[0029] In another aspect, a display device is provided. The display device includes a display panel as described in any of the above embodiments.

[0030] The above-described method for manufacturing the display panel and the display device have the same structure and beneficial technical effects as the display panels provided in some of the above embodiments, and will not be described again here. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in this disclosure, the accompanying drawings used in some embodiments of this disclosure will be briefly described below. Obviously, the drawings described below are only drawings of some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams and are not intended to limit the actual size of the product, the actual process of the method, etc. involved in the embodiments of this disclosure.

[0032] Figure 1 This is a structural diagram of a display device according to some embodiments of the present disclosure;

[0033] Figure 2 This is a structural diagram of a display panel according to some embodiments of the present disclosure;

[0034] Figure 3This is a structural diagram of a light-emitting device according to some embodiments of the present disclosure;

[0035] Figure 4 Here are the emission spectra of light-emitting devices according to some embodiments of this disclosure;

[0036] Figure 5 This is another structural diagram of a display panel according to some embodiments of the present disclosure;

[0037] Figure 6 This is yet another structural diagram of a display panel according to some embodiments of the present disclosure;

[0038] Figure 7 This is yet another structural diagram of a display panel according to some embodiments of the present disclosure;

[0039] Figure 8 This is yet another structural diagram of a display panel according to some embodiments of the present disclosure;

[0040] Figure 9 This is a flowchart of a method for manufacturing a display panel according to some embodiments of the present disclosure;

[0041] Figure 10 This is a graph showing the relationship between the external quantum efficiency and voltage of a light-emitting device according to some embodiments of the present disclosure. Detailed Implementation

[0042] The technical solutions in some embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided in this disclosure are within the scope of protection of this disclosure.

[0043] Unless the context otherwise requires, throughout the specification and claims, the term "comprise" and its other forms, such as the third-person singular "comprises" and the present participle "comprising," are interpreted as open-ended and encompassing, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiments," "example," "specific example," or "some examples," etc., are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples.

[0044] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more.

[0045] In describing some embodiments, the terms "coupled" and "connected," and their derivative expressions, may be used. The term "connected" should be interpreted broadly; for example, a "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection via an intermediate medium. The term "coupled," for example, indicates that two or more components have direct physical or electrical contact. The term "coupled" or "communicatively coupled" may also refer to two or more components that do not have direct contact with each other but still cooperate or interact with each other. The embodiments disclosed herein are not necessarily limited to the content of this document.

[0046] "At least one of A, B and C" has the same meaning as "at least one of A, B or C", both including the following combinations of A, B and C: only A, only B, only C, combinations of A and B, combinations of A and C, combinations of B and C, and combinations of A, B and C.

[0047] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0048] As used herein, “about,” “approximately,” or “approximately” includes the stated value and the average value within an acceptable range of deviation from the given value, wherein the acceptable range of deviation is determined by a person skilled in the art taking into account the measurement under discussion and the error associated with the measurement of the given quantity (i.e., the limitations of the measurement system).

[0049] As used herein, “parallel,” “perpendicular,” and “equal” include the described situation and situations that are similar to the described situation, within an acceptable range of deviation, which is determined by those skilled in the art taking into account the measurement under discussion and the error associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, “parallel” includes absolute parallelism and approximate parallelism, where an acceptable range of deviation for approximate parallelism may be, for example, within 5°; “perpendicular” includes absolute perpendicularity and approximate perpendicularity, where an acceptable range of deviation for approximate perpendicularity may also be, for example, within 5°; “equal” includes absolute equality and approximate equality, where an acceptable range of deviation for approximate equality may be, for example, a difference between the two equals being less than or equal to 5% of either one.

[0050] It should be understood that when a layer or element is referred to as being on another layer or substrate, it can mean that the layer or element is directly on the other layer or substrate, or that there is an intermediate layer between the layer or element and the other layer or substrate.

[0051] This document describes exemplary embodiments with reference to cross-sectional views and / or plan views, which are idealized exemplary drawings. In the drawings, the thickness of layers and the area of ​​regions are enlarged for clarity. Therefore, variations in shape relative to the drawings are contemplated due to, for example, manufacturing techniques and / or tolerances. Thus, exemplary embodiments should not be construed as being limited to the shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing processes. For example, etched areas shown as rectangular would typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to show the actual shapes of the areas of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0052] Some embodiments of this disclosure provide a display device 1000, which can be any device that displays text or images, whether in motion (e.g., video) or stationary (e.g., still images). More specifically, the embodiments are contemplated to be implemented in or associated with a variety of electronic devices, such as (but not limited to) mobile phones (e.g., cell phones), wireless devices, personal data assistants (PDAs), handheld or portable computers, GPS receivers / navigators, cameras, MP4 video players, camcorders, game consoles, watches, clocks, calculators, television monitors, flat panel displays, computer monitors, automotive displays (e.g., odometer displays, etc.), navigators, cockpit controllers and / or displays, displays of camera views (e.g., displays of rearview cameras in vehicles), electronic photographs, electronic billboards or signs, projectors, architectural structures, packaging and aesthetic structures (e.g., displays of images of a piece of jewelry), etc. Figure 1 The following is an illustration using a mobile phone as an example of a display device 1000.

[0053] For example, the display device 1000 can be an electroluminescent display device or a photoluminescent display device. When the display device 1000 is an electroluminescent display device, it can be an organic light-emitting diode (OLED) or a quantum dot light-emitting diode (QLED). When the display device 1000 is a photoluminescent display device, it can be a quantum dot photoluminescent display device. The following uses a QLED display device as an example to illustrate some embodiments of this disclosure; however, the implementation of this disclosure includes, but is not limited to, these embodiments, and any other display device can be considered as long as the same technical concept is applied.

[0054] Please continue reading. Figure 1 The aforementioned display device 1000 includes a display panel 100 and a driver chip, wherein the driver chip is used to drive the display panel 100 to perform display.

[0055] In some embodiments, such as Figure 2 As shown, the display panel 100 includes a substrate 20 and a pixel defining layer 30 located on one side of the substrate 20, wherein a plurality of openings Q are formed on the pixel defining layer 30. The display panel 100 also includes a plurality of light-emitting devices 10, which are disposed one-to-one in the plurality of openings Q.

[0056] For example, the plurality of light-emitting devices 10 include: a first light-emitting device 101, a second light-emitting device 102 and a third light-emitting device 103. The first light-emitting device 101 is configured to emit one of red light, blue light and green light, the second light-emitting device 102 is configured to emit another of red light, blue light and green light, and the third light-emitting device 103 is configured to emit the last of red light, blue light and green light, so as to realize full-color display of display panel 100.

[0057] The structure of the light-emitting device 10 is described below by way of example.

[0058] In some embodiments, such as Figure 3 As shown, the light-emitting device 10 includes: an anode 11, a quantum dot light-emitting layer 13 and a cathode 12 stacked together. A hole transport layer 14 is also disposed between the anode 11 and the quantum dot light-emitting layer 13, and an electron transport layer 15 is also disposed between the cathode 12 and the quantum dot light-emitting layer 13.

[0059] For example, the material of the quantum dot light-emitting layer 13 may include group II-VI semiconductor compounds, group III-V semiconductor compounds, group IV-VI semiconductor compounds, group IV semiconductors, group I-III-VI semiconductor compounds, group I-II-IV-VI semiconductor compounds, group II-III-V semiconductor compounds, or combinations thereof. For instance, the group II-VI semiconductor compound may be selected from: binary semiconductor compounds such as CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, or mixtures thereof; ternary semiconductor compounds such as CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, C dZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, or mixtures thereof; and quaternary semiconductor compounds such as HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, or mixtures thereof, but not limited thereto. For example, the III-V semiconductor compound may be selected from: binary semiconductor compounds such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, or mixtures thereof; ternary semiconductor compounds such as GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, or mixtures thereof; and quaternary semiconductor compounds such as GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, or mixtures thereof, but not limited thereto. For example, the IV-VI group semiconductor compound may be selected from: binary semiconductor compounds such as SnS, SnSe, SnTe, PbS, PbSe, PbTe, or mixtures thereof; ternary semiconductor compounds such as SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, or mixtures thereof; and quaternary semiconductor compounds such as SnPbSSe, SnPbSeTe, SnPbSTe, or mixtures thereof, but is not limited thereto.The group IV semiconductors may be selected, for example, from: elemental (monological) semiconductors such as Si, Ge, or mixtures thereof; and binary semiconductor compounds such as SiC, SiGe, and mixtures thereof, but are not limited thereto. The group I-III-VI semiconductor compounds may be, for example, CuInSe2, CuInS2, CuInGaSe, CuInGaS, or mixtures thereof, but are not limited thereto. The group I-II-IV-VI semiconductor compounds may be, for example, CuZnSnSe, CuZnSnS, or mixtures thereof, but are not limited thereto. The group II-III-V semiconductor compounds may include, for example, InZnP, but are not limited thereto.

[0060] The material of the quantum dot luminescent layer 13 can also be derived from perovskite structure materials. The general structural formula of perovskite materials is ABX3, where A represents an organic or inorganic cation, B represents a metal element, and X represents a halide anion, such as CsPbCl3, CsPbBr3, CsPhI3, CsPbCl3 / ZnS, CsPbBr3 / ZnS, CsPbI3 / ZnS, CsPbCl3 / ZnS, CsPbBr3 / ZnS, and CsPhI3 / ZnS.

[0061] The light-emitting principle of the light-emitting device 10 is as follows: through the circuit connected by the anode 11 and the cathode 12, holes are injected into the quantum dot light-emitting layer 13 by the anode 11 and electrons are injected into the quantum dot light-emitting layer 13 by the cathode 12. The injected electrons and holes form excitons (i.e. electron-hole pairs) in the quantum dot light-emitting layer 13. The excitons return to the ground state through radiative transition and emit photons.

[0062] By setting the hole transport layer 14, it is equivalent to setting a transition step between the anode 11 and the quantum dot light-emitting layer 13. By setting the electron transport layer 15, it is equivalent to setting a transition step between the cathode 12 and the quantum dot light-emitting layer 13. This reduces the potential barrier height that carrier transitions need to overcome, resulting in higher luminous efficiency of the light-emitting device 10.

[0063] For example, the hole transport layer 14 can be made of an organic material, such as poly(N-vinylcarbazole).

[0064] (polyvinylcarbazole, abbreviated as PVK), poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4′-(N-(4-sec-butylphenyl)diphenylamine)] (abbreviated as TFB), N,N'-diphenyl-N,N'-di(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (N,N'-Bis(3-methylphenyl)-N,N'-bis(phenyl)benzidine, abbreviated as TPD) or 4,4',4”-tris(N-carbazolyl)triphenylamine (4,4'-Cyclohexylidenebis[N,N-bis(4-methylphenyl)aniline], abbreviated as TAPC), etc.; or, the material of hole transport layer 14 can also be an inorganic oxide, such as nickel oxide or vanadium oxide.

[0065] For example, the material of the electron transport layer 15 can be zinc oxide or zinc magnesium oxide, etc. Here, zinc oxide or zinc magnesium oxide can be nanoparticles or thin films prepared by sputtering process.

[0066] In some embodiments, such as Figure 3 As shown, to improve luminous efficiency, the light-emitting device 10 further includes at least one of a hole injection layer (HIL) (not shown) and an electron blocking layer (EBL) (not shown). The hole injection layer, hole transport layer 14, and electron blocking layer are arranged sequentially toward the quantum dot light-emitting layer 13.

[0067] In some embodiments, such as Figure 3 As shown, to improve luminous efficiency, the light-emitting device 10 further includes at least one of an electron injection layer (EIL) (not shown) and a hole blocking layer (EBL) (not shown). The electron injection layer, electron transport layer 15, and hole blocking layer are arranged sequentially toward the quantum dot light-emitting layer 13.

[0068] In some examples, such as Figure 3 As shown, the light-emitting device 10 can be divided into upright light-emitting devices and inverted light-emitting devices.

[0069] like Figure 3 As shown, the anode 11, hole transport layer 14, quantum dot light-emitting layer 13, electron transport layer 15 and cathode 12 are arranged in a direction away from the substrate 20, and the light-emitting device 10 is an upright light-emitting device.

[0070] In other examples, the anode 11, hole transport layer 14, quantum dot light-emitting layer 13, electron transport layer 15, and cathode 12 are arranged in a direction close to the substrate 20, and the light-emitting device 10 is an inverted light-emitting device.

[0071] The inventor discovered that, such as Figure 2 and Figure 4 As shown, Figure 4 The image shows the emission spectrum of the light-emitting device 10 according to some embodiments of this disclosure. The horizontal axis represents wavelength in nm, and the vertical axis represents luminous intensity in counts. The electron transport layer 15 is made of magnesium zinc oxide. When the light-emitting device 10 is configured to emit blue light, see [reference needed]. Figure 4 The emission spectrum of the light-emitting device 10A shows a defect emission peak of zinc oxide in the wavelength range of 510 nm to 700 nm. Therefore, it can be inferred that in the light-emitting device 10A, electron transport is slower than hole transport, causing electrons and holes to recombine in the electron transport layer 15, resulting in a defect emission peak in the wavelength range of 510 nm to 700 nm, which reduces the luminous efficiency of the light-emitting device 10A.

[0072] The structure and fabrication method of the light-emitting device 10A are described in Example 1 below and will not be elaborated here.

[0073] See also Figure 2 The inventors also discovered that when the light-emitting device 10 is configured to emit either red or green light, electron transport is faster than hole transport, and the emission spectrum of the light-emitting device 10 contains emission peaks of the hole transport layer 14 material, which reduces the luminous efficiency of the light-emitting device 10.

[0074] Based on this, such as Figure 5 , Figure 6 and Figure 7 As shown, an embodiment of this disclosure provides a display panel 100, which includes a substrate 20 and a plurality of light-emitting devices 10 located on one side of the substrate 20. Each of the plurality of light-emitting devices 10 includes an electrode disposed opposite to each other, and a hole transport layer 14, a quantum dot light-emitting layer 13 and an electron transport layer 15 disposed between the oppositely disposed electrodes and stacked sequentially.

[0075] For example, the electrodes arranged opposite to each other include a first electrode 41 and a second electrode 42, where the first electrode 41 is one of the anode 11 and the cathode 12, and the second electrode 42 is the other of the anode 11 and the cathode 12. The embodiments of this disclosure are illustrated using a positive light-emitting device in which the first electrode 41 is the anode 11 and the second electrode 42 is the cathode 12 as an example. Some embodiments of this disclosure are not limited thereto.

[0076] The plurality of light-emitting devices 10 include: a first light-emitting device 101 and a second light-emitting device 102, wherein the first light-emitting device 101 is configured to emit blue light and the second light-emitting device 102 is configured to emit either red light or green light.

[0077] For example, the second light-emitting device 102 includes a second light-emitting device 102 configured to emit red light, and the second light-emitting device 102 also includes a second light-emitting device 102 configured to emit green light, so as to realize full-color display of the display panel 100.

[0078] The light-emitting device 10 further includes an additional functional layer 50, which includes at least one of a hole buffer layer 51, an electron buffer layer 52, a hole enhancement layer 54, and an electron enhancement layer 53.

[0079] Hole buffer layer 51 is located between hole transport layer 14 and quantum dot light-emitting layer 13 of the first light-emitting device 101, and is configured to reduce the hole transport speed; electron buffer layer 52 is located between quantum dot light-emitting layer 13 and electron transport layer 15 of the second light-emitting device 102, and is configured to reduce the electron transport speed; hole enhancement layer 54 is located between hole transport layer 14 and quantum dot light-emitting layer 13 of the second light-emitting device 102, and is configured to increase the hole transport speed; electron enhancement layer 53 is located between quantum dot light-emitting layer 13 and electron transport layer 15 of the first light-emitting device 101, and is configured to increase the electron transport speed.

[0080] For example, such as Figure 5 As shown, in the first light-emitting device 101, an additional functional layer 50 is located between the hole transport layer 14 and the quantum dot light-emitting layer 13. This additional functional layer 50 is called the hole buffer layer 51, and the hole buffer layer 51 is configured to reduce the hole transport speed.

[0081] As described above regarding the emission spectrum curve of the light-emitting device 10A when configured to emit blue light, in the first light-emitting device 101, electron transport is slower than hole transport; that is, hole transport is faster, causing electrons and holes to recombine in the electron transport layer 15. Therefore, by setting the hole buffer layer 51 to reduce the hole transport speed, electrons and holes recombine in the quantum dot light-emitting layer 13, thereby improving the luminous efficiency of the light-emitting device 10.

[0082] For example, such as Figure 6 As shown, in the second light-emitting device 102, an additional functional layer 50 is located between the quantum dot light-emitting layer 13 and the electron transport layer 15. This additional functional layer 50 is called the electron buffer layer 52, and the electron buffer layer 52 is configured to reduce the electron transport speed.

[0083] As described above regarding the emission spectrum of the light-emitting device 10 when configured to emit either red or green light, it is known that in the second light-emitting device 102, electron transport is faster than hole transport. This means that faster electron transport leads to recombination of electrons and holes in the hole transport layer 14. Therefore, by providing the electron buffer layer 52 to reduce the electron transport speed, electrons and holes recombine in the quantum dot light-emitting layer 13, thereby improving the luminous efficiency of the light-emitting device 10.

[0084] For example, such as Figure 7 As shown, in the first light-emitting device 101, an additional functional layer 50 is located between the quantum dot light-emitting layer 13 and the electron transport layer 15. This additional functional layer 50 is called the electron enhancement layer 53, and the electron enhancement layer 53 is configured to increase the electron transport speed.

[0085] As can be seen from the above description of the emission spectrum curve of the light-emitting device 10A when the light-emitting device 10 is configured to emit blue light, in the first light-emitting device 101, electron transport is slower than hole transport. That is, the slower electron transport causes electrons and holes to recombine in the electron transport layer 15. Therefore, by setting the electron enhancement layer 53 to increase the electron transport speed, electrons and holes recombine in the quantum dot light-emitting layer 13, thereby improving the luminous efficiency of the light-emitting device 10.

[0086] For example, such as Figure 7 As shown, in the second light-emitting device 102, an additional functional layer 50 is located between the hole transport layer 14 and the quantum dot light-emitting layer 13. This additional functional layer 50 is called the hole enhancement layer 54, and the hole enhancement layer 54 is configured to increase the hole transport speed.

[0087] As can be seen from the above description of the emission spectrum of the light-emitting device 10 when it is configured to emit either red light or green light, in the second light-emitting device 102, electron transport is faster than hole transport. That is, the slower hole transport causes electrons and holes to recombine in the hole transport layer 14. Therefore, by setting the hole enhancement layer 54 to increase the hole transport speed, electrons and holes recombine in the quantum dot light-emitting layer 13, thereby improving the luminous efficiency of the light-emitting device 10.

[0088] In some embodiments, such as Figure 5 As shown, the material of the hole buffer layer 51 includes at least one of the following: insulating material, interfacial dipole material, and electron transport material.

[0089] For example, the insulating material includes at least one of poly(methyl methacrylate, abbreviated as PMMA), aluminum oxide, and polyvinylpyrrolidone polymer, abbreviated as PVP.

[0090] Insulating materials can impede the transport of charge carriers. When the thickness d1 of the hole buffer layer 51 formed by the insulating material is appropriate, holes can pass through the hole buffer layer 51 through the tunneling effect. Forming a hole buffer layer 51 by using insulating material can reduce the transport speed of holes, thereby balancing the transport of holes and electrons in the first light-emitting device 101 and improving the luminous efficiency of the first light-emitting device 101.

[0091] For example, the interfacial dipole material includes at least one of poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-di-n-octylfluorenyl-2,7-diyl))(Poly[9,9-bis(3′-(N,N-dimethyl)-propyl-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)], abbreviated as PFN) and polyethylenimine ethoxylated (abbreviated as PEIE).

[0092] The interface dipole material can form an electric field from the quantum dot light-emitting layer 13 to the hole transport layer 14 to hinder hole transport, reduce hole transport speed, balance the transport of holes and electrons in the first light-emitting device 101, and improve the luminous efficiency of the first light-emitting device 101.

[0093] Interfacial dipole materials are materials that can form dipoles at the molecular level. Interfacial dipoles can be detected by various experimental characterization techniques such as X-ray photoelectron spectroscopy, ultraviolet-visible absorption spectroscopy, Fourier transform infrared spectroscopy, surface plasmon resonance, or scanning probe microscopy.

[0094] For example, the electron transport material includes at least one of naphthalimide and poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-bis-n-octylfluorenyl-2,7-diyl)bromo]

[0095] The electron transport material has a high HOMO (Highest Occupied Molecular Orbital) energy level. The hole buffer layer 51 formed by the electron transport material can form an energy level barrier that hinders hole transport, thereby reducing the hole transport speed and balancing the transport of holes and electrons in the first light-emitting device 101, thus improving the luminous efficiency of the first light-emitting device 101.

[0096] In other embodiments, such as Figure 5 As shown, the material of the hole buffer layer 51 includes: a first crosslinking material, which is formed by crosslinking the first material with a photosensitive crosslinking agent through a hydrocarbon insertion reaction; the first material includes at least one of polymethyl methacrylate, poly[(9,9-di(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-di-n-octylfluorenyl-2,7-diyl) and polyvinylpyrrolidone.

[0097] Polymethyl methacrylate (PMMA) and polyvinylpyrrolidone (PVP) are used as insulating materials, while poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-di-n-octylfluorenyl-2,7-diyl)] is used as an interfacial dipole material. Both the insulating material and the interfacial dipole material can reduce the hole propagation speed.

[0098] The first cross-linked material formed by the cross-linking of the first material and the photosensitive cross-linking agent through a hydrocarbon insertion reaction serves as a hole buffer layer 51. After participating in the cross-linking reaction, the first material retains its function of reducing hole transport speed. Details regarding the formation of the first cross-linked material using the first material and the photosensitive cross-linking agent will be provided later and will not be elaborated upon here.

[0099] In some examples, the photosensitive crosslinking agent includes at least one of carbene precursors, azide derivatives, and photosensitive metal complexes.

[0100] Carbene, also known as carbene or carbene, is usually formed by the elimination of a neutral molecule from a molecule containing an easily leaving group. Like carbon radicals, it is a neutral and reactive intermediate without positive or negative charge. Carbene is the general term for H₂C₂ and its substituted derivatives. A carbene contains an electrically neutral divalent carbon atom with two unbonded electrons. It is a highly reactive intermediate containing two unbonded electrons. Carbene precursors can form carbene, which crosslinks with the first material through a hydrocarbon insertion reaction to form the first crosslinked material, thus forming a hole buffer layer 51.

[0101] For example, carbene precursors include at least one of diazacyclopropene and triazaene.

[0102] For example, azide derivatives include at least one of sulfonyl azide, phenyl azide, and perfluoroalkyl azide.

[0103] For example, photosensitive metal complexes include at least one of bipyridine ruthenium and iridium complexes.

[0104] The first material is an organic material that does not contain carbon-carbon double bonds, and the photosensitive crosslinking agent is a crosslinking agent that can undergo a hydrocarbon insertion reaction. By setting the materials of the first material and the photosensitive crosslinking agent, the first material and the photosensitive crosslinking agent can form a hole buffer layer 51 through a hydrocarbon insertion reaction.

[0105] In some embodiments, such as Figure 5 As shown, the thickness d1 of the hole buffer layer 51 ranges from 5 nm to 8 nm.

[0106] For example, the thickness d1 of the hole buffer layer 51 can be 5nm, 5.5nm, 6nm, 6.5nm, 7nm, 7.5nm or 8nm, etc., and there is no limit here.

[0107] By setting the thickness d1 of the hole buffer layer 51 to be in the range of 5nm to 8nm, holes can pass through the hole buffer layer 51 while reducing the hole transmission speed, so as to balance the transmission of holes and electrons in the first light-emitting device 101 and improve the luminous efficiency of the first light-emitting device 101.

[0108] In some embodiments, such as Figure 6 As shown, the electron buffer layer 52 comprises: a second crosslinking material, which is formed by crosslinking a second material with a photosensitive crosslinking agent through a hydrocarbon insertion reaction; the second material comprises: an insulating organic material with a carrier mobility less than or equal to 10. -6 cm 3 At least one of the following: organic materials with an energy level of / v·s and P-type semiconductor materials with an energy level greater than or equal to -2.6eV of LUMO (Lowest Unoccupied Molecular Orbital).

[0109] For example, the insulating organic material includes at least one of polymethyl methacrylate and polyvinylpyrrolidone. The insulating organic material can impede carrier transport; when the thickness d2 of the electron buffer layer 52 formed by the insulating organic material is appropriate, electrons can tunnel through the electron buffer layer 52. The electron buffer layer 52 formed by crosslinking the insulating organic material and the photosensitive crosslinking agent through a hydrocarbon insertion reaction can reduce the electron transport speed, thereby balancing the transport of holes and electrons in the second light-emitting device 102 and improving the luminous efficiency of the second light-emitting device 102.

[0110] Carrier mobility less than or equal to 10 -6 cm3 Organic materials with a density of / v·s have low carrier mobility, which can be used to impede electron transport and reduce the electron transport speed.

[0111] For example, P-type semiconductor materials with LUMO levels greater than or equal to -2.6 eV include at least one of poly(9,9-n-dioctyl-2,7-fluorene-alt-9-isooctyl-3,6-carbazole) and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4′-(N-(4-sec-butylphenyl)diphenylamine)].

[0112] The second cross-linked material formed by the hydrocarbon insertion reaction of a P-type semiconductor material with a LUMO level greater than or equal to -2.6 eV and a photosensitive cross-linking agent can form a large energy level barrier to hinder electron transport, reduce the electron transport speed, balance the transport of holes and electrons in the second light-emitting device 102, and improve the luminous efficiency of the second light-emitting device 102.

[0113] For an introduction to photosensitive crosslinking agents, please refer to the above content; it will not be repeated here.

[0114] In some embodiments, such as Figure 6 As shown, the thickness d2 of the electron buffer layer 52 ranges from 5 nm to 8 nm.

[0115] For example, the thickness d2 of the electron buffer layer 52 can be 5nm, 5.5nm, 6nm, 6.5nm, 7nm, 7.5nm or 8nm, etc., and there is no limit here.

[0116] By setting the thickness d2 of the electron buffer layer 52 to be in the range of 5nm to 8nm, electrons can pass through the electron buffer layer 52 while reducing the electron transmission speed, so as to balance the transmission of holes and electrons in the second light-emitting device 102 and improve the luminous efficiency of the second light-emitting device 102.

[0117] Among them, such as Figure 6 As shown, the example given is that both the second light-emitting device 102 emitting red light and the second light-emitting device 102 emitting green light are provided with an electron buffer layer 52. However, some embodiments of this disclosure are not limited to this. For example, the second light-emitting device 102 emitting red light may have an electron buffer layer 52, while the second light-emitting device 102 emitting green light may not have an electron buffer layer 52. Alternatively, the second light-emitting device 102 emitting red light may not have an electron buffer layer 52, while the second light-emitting device 102 emitting green light may have an electron buffer layer 52.

[0118] In some embodiments, such as Figure 5 and Figure 6As shown, the surface m1 of the electrode on the side of the first light-emitting device 101 away from the substrate 20 is not flush with the surface m2 of the electrode on the side of the second light-emitting device 102 away from the substrate 20.

[0119] For example, the electrode on the side of the first light-emitting device 101 away from the substrate 20 and the electrode on the side of the second light-emitting device 102 away from the substrate 20 are both cathodes 12. The surface m1 of the cathode 12 of the first light-emitting device 101 away from the substrate 20 and the surface m2 of the cathode 12 of the second light-emitting device 102 away from the substrate 20 are not flush.

[0120] For example, such as Figure 5 As shown, the first light-emitting device 101 includes a hole buffer layer 51. Therefore, the surface m1 of the cathode 12 of the first light-emitting device 101 that is away from the substrate 20 is further away from the substrate 20 than the surface m2 of the cathode 12 of the second light-emitting device 102 that is away from the substrate 20.

[0121] For example, such as Figure 6 As shown, the second light-emitting device 102 includes an electron buffer layer 52. Therefore, the surface m2 of the cathode 12 of the second light-emitting device 102 that is away from the substrate 20 is further away from the substrate 20 than the surface m1 of the cathode 12 of the first light-emitting device 101 that is away from the substrate 20.

[0122] In other embodiments, the second light-emitting device 102 emitting red light is provided with an electron buffer layer 52, while the second light-emitting device 102 emitting green light is not provided with an electron buffer layer 52. The surface of the cathode 12 of the second light-emitting device 102 emitting red light away from the substrate 20 is further away from the substrate 20 than the surface of the second light-emitting device 102 emitting green light away from the substrate 20.

[0123] In some other embodiments, the second light-emitting device 102 emitting red light is not provided with an electron buffer layer 52, while the second light-emitting device 102 emitting green light is provided with an electron buffer layer 52. The surface of the cathode 12 of the second light-emitting device 102 emitting green light that is away from the substrate 20 is further away from the substrate 20 than the surface of the second light-emitting device 102 emitting red light that is away from the substrate 20.

[0124] In some embodiments, such as Figure 5 and Figure 6 As shown, the distance d3 between the surface m1 of the electrode of the first light-emitting device 101 away from the substrate 20 and the surface m2 of the electrode of the second light-emitting device 102 away from the substrate 20 in the first direction Y is in the range of 5nm to 8nm; wherein, the first direction Y is perpendicular to the substrate 20.

[0125] For example, such as Figure 5 and Figure 6As shown, the distance d3 between the surface m1 of the cathode 12 of the first light-emitting device 101 away from the substrate 20 and the surface m2 of the cathode 12 of the second light-emitting device 102 away from the substrate 20 in the first direction Y ranges from 5nm to 8nm.

[0126] For example, the distance d3 between the surface m1 of the electrode of the first light-emitting device 101 away from the substrate 20 and the surface m2 of the electrode of the second light-emitting device 102 away from the substrate 20 in the first direction Y is 5nm, 5.5nm, 6nm, 6.5nm, 7nm, 7.5nm or 8nm, etc., and there is no limitation here.

[0127] Due to the arrangement of additional functional layers 50 on different light-emitting devices 10, a distance d3 will exist between the surface m1 of the electrode of the first light-emitting device 101 away from the substrate 20 and the surface m2 of the electrode of the second light-emitting device 102 away from the substrate 20 in the first direction Y.

[0128] In some embodiments, such as Figure 8 As shown, a hole buffer layer 51 is provided between the hole transport layer 14 and the quantum dot light-emitting layer 13 of the first light-emitting device 101, and an electron buffer layer 52 is provided between the quantum dot light-emitting layer 13 and the electron transport layer 15 of the second light-emitting device 102.

[0129] By setting a hole buffer layer 51 between the hole transport layer 14 and the quantum dot light-emitting layer 13 of the first light-emitting device 101, and setting an electron buffer layer 52 between the quantum dot light-emitting layer 13 and the electron transport layer 15 of the second light-emitting device 102, the carrier transport balance of the first light-emitting device 101 and the carrier transport balance of the second light-emitting device 102 are simultaneously adjusted, so that electrons and holes recombine in the quantum dot light-emitting layer 13, thereby improving the luminous efficiency of the light-emitting device 10.

[0130] For example, such as Figure 8 As shown, the surface m1 of the electrode of the first light-emitting device 101 on the side away from the substrate 20 is flush with the surface m2 of the electrode of the second light-emitting device 102 on the side away from the substrate 20.

[0131] In some embodiments, such as Figure 7 As shown, the material of the electron enhancement layer 53 includes at least one of an interface dipole material and an electron transport material.

[0132] The interface dipole material can form an electric field from the electron transport layer 15 to the quantum dot light-emitting layer 13 to promote electron transport and increase the electron transport speed, so as to balance the transport of holes and electrons in the first light-emitting device 101 and improve the luminous efficiency of the first light-emitting device 101.

[0133] Electron transport materials promote electron transport, thereby increasing the speed of electron transport.

[0134] For example, the material of the electron enhancement layer 53 includes: a fourth crosslinking material, which is formed by crosslinking the fourth material with a photosensitive crosslinking agent through a hydrocarbon insertion reaction; the fourth material includes at least one of poly[(9,9-di(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-di-n-octylfluorenyl-2,7-diyl), poly[(9,9-di(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-di-n-octylfluorenyl-2,7-diyl)-bromo] and polyethoxyethyleneimine.

[0135] Poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-di-n-octylfluorenyl-2,7-diyl), poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-di-n-octylfluorenyl-2,7-diyl)-bromine] and polyethoxyethyleneimine can all form an electric field from the electron transport layer 15 to the quantum dot emitting layer 13 to promote electron transport. Poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-di-n-octylfluorenyl-2,7-diyl)-bromine] is also called an electron transport material and has the effect of promoting electron transport.

[0136] For an introduction to photosensitive crosslinking agents, please refer to the above content; it will not be repeated here.

[0137] In some embodiments, such as Figure 7 As shown, the thickness d5 of the electron enhancement layer 53 ranges from 3 nm to 5 nm.

[0138] For example, the thickness d5 of the electron enhancement layer 53 is 3nm, 3.2nm, 3.5nm, 3.8nm, 4nm, 4.5nm or 5nm, etc., and there is no limitation here.

[0139] By setting the thickness d5 of the electron enhancement layer 53 to be in the range of 3nm to 5nm, the electron enhancement layer 53 can promote electron transport while ensuring a balance between the electron transport speed and the hole transport speed, thereby improving the luminous efficiency of the first light-emitting device 101.

[0140] In some embodiments, such as Figure 7 As shown, the hole enhancement layer 54 is made of a third crosslinking material, which is formed by crosslinking the third material and the photosensitive crosslinking agent through a hydrocarbon insertion reaction; the HOMO energy level range of the third material is -5.3 eV to -6.0 eV.

[0141] The HOMO energy level range of the third material is -5.3 eV to -6.0 eV. After the third material and the photosensitive crosslinking agent are crosslinked through a hydrocarbon insertion reaction to form the third crosslinked material, the HOMO energy level range of the third crosslinked material is approximately -5.3 eV to -6.0 eV.

[0142] For example, in the second light-emitting device 102, the hole transport layer 14 is made of TFB, and the HOMO energy level of TFB is -5.3 eV. The HOMO energy level range of the third cross-linking material is set to be approximately -5.3 eV to -6.0 eV, which is equivalent to forming a stepped energy level between the hole transport layer 14 and the quantum dot light-emitting layer 13. This is beneficial for holes to be transported from the hole transport layer 14 to the quantum dot light-emitting layer 13. Therefore, the hole enhancement layer 54 has the function of increasing the hole transport speed.

[0143] For an introduction to photosensitive crosslinking agents, please refer to the above content; it will not be repeated here.

[0144] In some embodiments, the third material includes at least one of: polyvinylcarbazole, 4,4,4,-tris(carbazole-9-yl)triphenylamine, N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine, and 4,4'-bis(N-carbazole)biphenyl.

[0145] The HOMO levels of polyvinylcarbazole, 4,4,4,-tris(carbazole-9-yl)triphenylamine, N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine, and 4,4'-bis(N-carbazole)biphenyl are located between -5.3 eV and -6.0 eV, so that the formed hole enhancement layer 54 can increase the hole transport speed.

[0146] In some embodiments, such as Figure 7 As shown, the thickness d5 of the hole enhancement layer 54 ranges from 8 nm to 12 nm.

[0147] For example, the thickness d5 of the hole enhancement layer 54 can be 8nm, 8.5nm, 9nm, 9.5nm, 10nm, 10.5nm, 11nm, 11.5nm or 12nm, etc., and there is no limit here.

[0148] By setting the thickness d5 of the hole enhancement layer 54 to be in the range of 8nm to 12nm, the electron transport speed of the second light-emitting device 10 can be effectively improved, so as to balance the transport of holes and electrons in the second light-emitting device 102 and improve the luminous efficiency of the second light-emitting device 102.

[0149] In some embodiments, such as Figure 8As shown, the material of the quantum dot luminescent layer 13 includes: a fifth cross-linking material, which is formed by cross-linking quantum dot material with a cross-linking agent. Alternatively, the material of the quantum dot luminescent layer 13 is formed by cross-linking quantum dots with photosensitive ligands.

[0150] For example, the quantum dot material can be selected from one or more of group II-VI, group IV-VI, or group III-V compounds, such as CdS, CdSe, ZnSe, ZnTeSe, InP, PbS, CdS / ZnS, CdSe / ZnS, ZnSe, ZnSeTe, InP / ZnS, PbS / ZnS, CdS / ZnSeS / ZnS, CdSe / ZnSeS / ZnS, ZnSe / ZnSeS / ZnS, ZnSeTe / ZnSeS / ZnS, InP / ZnS, and any combination of one or more of PbS / ZnS. Quantum dot materials can also be derived from perovskite structure materials. The general structural formula of perovskite materials is ABX3, where A represents an organic or inorganic cation, B represents a metal element, and X represents a halide anion, such as CsPbCl3, CsPbBr3, CsPhI3, CsPbCl3 / ZnS, CsPbBr3 / ZnS, CsPbI3 / ZnS, CsPbCl3 / ZnS, CsPbBr3 / ZnS, and CsPhI3 / ZnS.

[0151] For example, the crosslinking agent is a photosensitive crosslinking agent, such as at least one of benzoin methyl ether, acrylate monomers, benzoyl ketals, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, azide derivatives, benzophenone, and thioxanthone.

[0152] Among them, benzoindimethylether, with CAS number 246504-2-8, has the molecular formula C2. 16 H 16 O3 is a colorless to pale yellow transparent liquid at room temperature with a characteristic odor. It is a highly efficient UV curing initiator, mainly used as an initiator for UV curing reactions.

[0153] Acrylic ester monomers are a type of elastomer that are copolymerized with alkyl acrylate (CH2=CH-COO-) as the main monomer and a small amount of monomers with crosslinking reactive groups.

[0154] bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, also known as photoinitiator 819, is a compound with the molecular formula C1. 26 H 27O3P.

[0155] Azides are a class of compounds with the general formula RN3, where R is an aliphatic group, aromatic group, acyl group, sulfonyl group, or hydrogen, etc. Exemplary examples of azide derivatives include at least one of sulfonyl azides, phenyl azides, and perfluoroalkyl azides.

[0156] Benzophenone, chemical formula: C 13 H 10 O.

[0157] Thioxanthone, also known as thioxanthone, has the structural formula C. 16 H 10 OS.

[0158] For example, benzoyl ketals include at least one of 2,2-dimethoxy-2-phenylacetophenone and 2-hydroxy-2-methyl-1-phenyl-1-propanone.

[0159] Among them, 2,2-dimethoxy-2-phenylacetophenone, also known as benzoin diethyl ether and photoinitiator 651 (BDK), has the English name 2,2-Dimethoxy-2-phenylacetophenone and the molecular formula C. 16 H 16 O3. 2-Hydroxy-2-methyl-1-phenyl-1-propanone, with the chemical formula C3, has the English name 2-hydroxy-2-methylpropiophenone and the chemical formula C3. 10 H 12 O2.

[0160] In other embodiments, such as Figure 8 As shown, the material of the quantum dot luminescent layer 13 is formed by cross-linking quantum dots with photosensitive ligands.

[0161] For example, the photosensitive ligand can be a ligand containing a diacrylidine group, a benzophenone group, or a diazo group. A diacrylidine group is a three-membered ring structure containing two nitrogen atoms and a central carbon atom. A diazo group is a divalent atomic group composed of two nitrogen atoms linked together.

[0162] In other embodiments, such as Figure 8 As shown, the thickness d6 of the quantum dot light-emitting layer 13 ranges from 20 nm to 30 nm.

[0163] For example, the thickness d6 of the quantum dot light-emitting layer 13 is 20nm, 22nm, 25nm, 27nm, 28nm, 29nm or 30nm, etc., and there is no limitation here.

[0164] like Figures 5-7As shown, embodiments of this disclosure also provide a method for fabricating a display panel, the method comprising: forming a plurality of light-emitting devices 10 on one side of a substrate 20, each of the plurality of light-emitting devices 10 comprising: an electrode disposed opposite to each other, and a hole transport layer 14, a quantum dot light-emitting layer 13 and an electron transport layer 15 disposed between the oppositely disposed electrodes and stacked sequentially; the plurality of light-emitting devices 10 comprising: a first light-emitting device 101 and a second light-emitting device 102, the first light-emitting device 101 being configured to emit blue light, and the second light-emitting device 102 being configured to emit either red light or green light.

[0165] At least one light-emitting device 10 further includes: an additional functional layer 50; the additional functional layer 50 includes at least one of: a hole buffer layer 51, an electron buffer layer 52, a hole enhancement layer 54, and an electron enhancement layer 53; the hole buffer layer 51 is located between the hole transport layer 14 and the quantum dot light-emitting layer 13 of the first light-emitting device 101, and the hole buffer layer 51 is configured to reduce the hole transport speed; the electron buffer layer 52 is located between the quantum dot light-emitting layer 13 and the electron transport layer 15 of the second light-emitting device 102, and the electron buffer layer 52 is configured to reduce the electron transport speed; the hole enhancement layer 54 is located between the hole transport layer 14 and the quantum dot light-emitting layer 13 of the second light-emitting device 102, and the hole enhancement layer 54 is configured to increase the hole transport speed; the electron enhancement layer 53 is located between the quantum dot light-emitting layer 13 and the electron transport layer 15 of the first light-emitting device 101, and the electron enhancement layer 53 is configured to increase the electron transport speed.

[0166] The contents of the additional functional layer 50 are described above and will not be repeated here.

[0167] In some embodiments, such as Figures 5-9 As shown, forming a plurality of light-emitting devices 10 on one side of the substrate 20 includes forming an additional functional layer 50, wherein the additional functional layer 50 includes the following steps S1 to S3.

[0168] S1. Form an initial material layer, which includes: a functional material and a photosensitive crosslinking agent. The functional material includes any one of the first material, the second material, the third material, and the fourth material.

[0169] For example, the initial material layer is formed by spin coating.

[0170] For example, the first material includes at least one of polymethyl methacrylate, poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-di-n-octylfluorenyl-2,7-diyl) and polyvinylpyrrolidone.

[0171] For example, the second material includes: an insulating organic material, and a carrier mobility less than or equal to 10. -6 cm 3 At least one of the following: organic materials with an energy level of / v·s and P-type semiconductor materials with an LUMO level greater than or equal to -2.6eV.

[0172] For example, the third material includes at least one of: polyvinylcarbazole, 4,4,4,-tris(carbazole-9-yl)triphenylamine, N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine and 4,4'-bis(N-carbazole)biphenyl.

[0173] For example, the fourth material includes at least one of poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-di-n-octylfluorenyl-2,7-diyl), poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-di-n-octylfluorenyl-2,7-diyl)-bromo] and polyethoxyethyleneimine.

[0174] For example, the photosensitive crosslinking agent includes at least one of carbene precursors, azide derivatives, and photosensitive metal complexes.

[0175] S2, Expose the initial material layer, forming the exposed area material and the non-exposed area material from the initial material layer.

[0176] For example, an initial material layer is exposed by a mask to form exposed area material and non-exposed area material.

[0177] For example, the exposure area material is a first crosslinked material formed by crosslinking the first material and the photosensitive crosslinking agent through a hydrocarbon insertion reaction, and the exposure area material is used to form the hole buffer layer 51.

[0178] For example, the exposed region material is a second crosslinked material formed by crosslinking the second material with a photosensitive crosslinking agent through a hydrocarbon insertion reaction, and this exposed region material is used to form the electron buffer layer 52.

[0179] For example, the exposed region material is a third crosslinked material formed by crosslinking a third material with a photosensitive crosslinking agent through a hydrocarbon insertion reaction, and this exposed region material is used to form the hole reinforcement layer 54.

[0180] For example, the exposed region material is a fourth crosslinked material formed by crosslinking a fourth material with a photosensitive crosslinking agent through a hydrocarbon insertion reaction, and this exposed region material is used to form the electron enhancement layer 53.

[0181] S3. Remove the non-exposed area material from the initial material layer to obtain the additional functional layer 50.

[0182] The unexposed areas of the initial material layer are removed by development, while the exposed areas of the initial material layer are retained to form the additional functional layer 50.

[0183] Through the above steps S1 to S3, an additional functional layer 50 is formed by the cross-linking reaction between the functional material and the photosensitive cross-linking agent.

[0184] Based on the above description of the structure of the display panel 100 and the method for manufacturing the display panel, the following example is provided.

[0185] Example 1

[0186] Example 1 is a comparative example, such as Figure 2 and Figure 4 As shown, the light-emitting device 10 in the comparative example is designated as light-emitting device 10A. The fabrication method of light-emitting device 10A is as follows.

[0187] The indium tin oxide (ITO) substrate was ultrasonically cleaned for 15 minutes with deionized water and isopropanol, then dried with nitrogen and baked at 135°C for 5 minutes.

[0188] The ITO substrate was treated with ultraviolet ozone for 10 minutes to further clean the organic contaminants attached to the ITO surface and passivate the ITO surface defects.

[0189] A hole injection layer with a thickness of 25 nm is formed by spin-coating poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS) onto an ITO substrate, and then baking at 130°C for 20 min.

[0190] TFB material was spin-coated onto the hole injection layer to form a hole transport layer 14 with a thickness of 20 nm, and then baked at 130 °C for 20 min.

[0191] Quantum dot material was spin-coated onto hole transport layer 14 to form quantum dot light-emitting layer 13. The thickness d6 of quantum dot light-emitting layer 13 was 20 nm, and then it was baked at 100 °C for 5 min.

[0192] ZnMgO was spin-coated onto the quantum dot luminescent layer 13 to form an electron transport layer 15 with a thickness of 50 nm, and then baked at 80 °C for 10 min.

[0193] The substrate with the above-mentioned film layer was placed in an evaporation machine to deposit Al electrodes under a vacuum degree of 1×10⁻⁶. -6 mbar, evaporation rate is The film thickness is 100 nm. An Al electrode forms the cathode 12.

[0194] The above-mentioned device was encapsulated using a glass cover and UV-curable adhesive to obtain the light-emitting device 10A.

[0195] Example 2

[0196] like Figure 4 and Figure 5 In Example 2, the light-emitting device 10 is designated as light-emitting device 10B. Compared to Comparative Example 1, the light-emitting device 10B of Example 2 includes a hole buffer layer 51.

[0197] The ITO substrate was ultrasonically cleaned with deionized water and isopropanol for 15 minutes each, then dried with nitrogen and baked at 135°C for 5 minutes.

[0198] The ITO substrate was treated with ultraviolet ozone for 10 minutes to further clean the organic contaminants attached to the ITO surface and passivate the ITO surface defects.

[0199] PEDOT:PSS material was spin-coated onto an ITO substrate to form a hole injection layer with a thickness of 25 nm, and then baked at 130 °C for 20 min.

[0200] TFB material was spin-coated onto the hole injection layer to form a hole transport layer 14 with a thickness of 20 nm, and then baked at 130 °C for 20 min.

[0201] PMMA material is spin-coated onto hole transport layer 14 to form hole buffer layer 51. The thickness d1 of hole buffer layer 51 is 8 nm, and then it is baked at 120°C for 10 min.

[0202] Quantum dot material is spin-coated onto hole buffer layer 51 to form quantum dot light-emitting layer 13. The thickness d6 of quantum dot light-emitting layer 13 is 20 nm, and then it is baked at 100 °C for 5 min.

[0203] ZnMgO was spin-coated onto the quantum dot luminescent layer 13 to form an electron transport layer 15 with a thickness of 50 nm, and then baked at 80 °C for 10 min.

[0204] The substrate with the above-mentioned film layer was placed in an evaporation machine to deposit Al electrodes under a vacuum degree of 1×10⁻⁶. -6 mbar, evaporation rate is The film thickness is 100 nm.

[0205] The above-mentioned device is encapsulated using a glass cover and UV-curable adhesive to obtain the light-emitting device 10B.

[0206] By comparison Figure 4The emission spectrum curves of light-emitting device 10A and light-emitting device 10B are shown in the figure. Light-emitting device 10A shows a defect emission peak of zinc oxide in the wavelength range of 510nm to 700nm, while the emission peak of light-emitting device 10B, which has a hole buffer layer 51, is concentrated in the range of 420nm to 550nm. No defect emission peak of zinc oxide is found in the range of 510nm to 700nm. This indicates that the hole buffer layer 51 reduces the hole transport speed, which allows electrons and holes in light-emitting device 10B to recombine in the quantum dot light-emitting layer 13, thereby improving the luminous efficiency of light-emitting device 10.

[0207] Figure 10 This is a graph showing the relationship between the external quantum efficiency and voltage of a light-emitting device 10 according to some embodiments of the present disclosure, where the horizontal axis represents voltage in V and the vertical axis represents external quantum efficiency. Figure 10 It can be seen that by setting the hole buffer layer 51, the external quantum efficiency of the light-emitting device 10 is significantly improved.

[0208] Example 3

[0209] The structure of the display panel 100 is as follows: Figure 5 As shown, a hole buffer layer 51 is provided between the quantum dot light-emitting layer 13 and the hole transport layer 14 of the first light-emitting device 101 that emits blue light, while no hole buffer layer 51 is provided between the quantum dot light-emitting layer 13 and the hole transport layer 14 of the second light-emitting device 102 that emits red or green light. The method for fabricating the display panel is as follows.

[0210] The ITO substrate was ultrasonically cleaned with deionized water and isopropanol for 15 minutes each, then dried with nitrogen and baked at 135°C for 5 minutes.

[0211] The ITO substrate was treated with ultraviolet ozone for 10 minutes to further clean the organic contaminants attached to the ITO surface and passivate the ITO surface defects.

[0212] PEDOT:PSS material was spin-coated onto an ITO substrate to form a hole injection layer with a thickness of 25 nm, and then baked at 130 °C for 20 min.

[0213] TFB material was spin-coated onto the hole injection layer to form a hole transport layer 14 with a thickness of 20 nm, and then baked at 130 °C for 20 min.

[0214] A mixture of PMMA and photosensitive crosslinking agent is spin-coated onto the hole transport layer 14. After exposure and development, the PMMA at the location where the first light-emitting device 101 is to be formed is chemically bonded to the photosensitive crosslinking agent to form a crosslinking network, thus forming the hole buffer layer 51. The PMMA and photosensitive crosslinking agent at the location where the second light-emitting device 102 is to be formed are removed during the development process.

[0215] A mixture of quantum dot material and crosslinking agent is spin-coated, or quantum dots with photosensitive ligands are spin-coated. Ultraviolet light irradiation causes crosslinking of the quantum dots at the positions corresponding to the red-emitting second light-emitting device 102. This portion is used to form the quantum dot light-emitting layer 13 of the red-emitting second light-emitting device 102. Then, the quantum dot material and crosslinking agent at the positions corresponding to the green-emitting second light-emitting device 102 and the first light-emitting device 101 are removed using a solvent-based development method.

[0216] A mixture of quantum dot material and crosslinking agent is spin-coated, or quantum dots with photosensitive ligands are spin-coated. Ultraviolet light irradiation causes crosslinking of the quantum dots at the positions corresponding to the green light-emitting device 102. This portion is used to form the quantum dot light-emitting layer 13 of the green light-emitting device 102. Then, the quantum dot material and crosslinking agent at the positions of the second light-emitting device 102 and the first light-emitting device 101, which emit red light, are removed using solvent development of the quantum dot material.

[0217] A mixture of quantum dot material and crosslinking agent is spin-coated, or quantum dots with photosensitive ligands are spin-coated. Ultraviolet light irradiation causes the quantum dots at the corresponding positions of the first light-emitting device 101 to crosslink, and this portion is used to form the quantum dot light-emitting layer 13 of the first light-emitting device 101. Then, the quantum dot material and crosslinking agent at the positions of the second light-emitting device 102 emitting red light and the second light-emitting device 102 emitting green light are removed by solvent development of the quantum dot material.

[0218] Then bake at 100℃ for 5 minutes to form quantum dot luminescent layer 13.

[0219] ZnMgO was spin-coated onto the quantum dot luminescent layer 13 to form an electron transport layer 15 with a thickness of 50 nm, and then baked at 80 °C for 10 min.

[0220] The substrate with the above-mentioned film layer was placed in an evaporation machine to deposit Al electrodes under a vacuum degree of 1×10⁻⁶. -6 mbar, evaporation rate is The film thickness is 100 nm.

[0221] The above-mentioned devices are encapsulated using a glass cover and UV-curable adhesive to form a display panel 100.

[0222] Example 4

[0223] The structure of the display panel 100 is as follows: Figure 6 As shown, an electron buffer layer 52 is provided between the quantum dot light-emitting layer 13 and the electron transport layer 15 of the second light-emitting device 102 emitting red light and the second light-emitting device 102 emitting green light, while no electron buffer layer 52 is provided between the quantum dot light-emitting layer 13 and the electron transport layer 15 of the first light-emitting device 101. The method for fabricating the display panel is as follows.

[0224] The ITO substrate was ultrasonically cleaned with deionized water and isopropanol for 15 minutes each, then dried with nitrogen and baked at 135°C for 5 minutes.

[0225] The ITO substrate was treated with ultraviolet ozone for 10 minutes to further clean the organic contaminants attached to the ITO surface and passivate the ITO surface defects.

[0226] PEDOT:PSS material was spin-coated onto an ITO substrate to form a hole injection layer with a thickness of 25 nm, and then baked at 130 °C for 20 min.

[0227] TFB material was spin-coated onto the hole injection layer to form a hole transport layer 14 with a thickness of 20 nm, and then baked at 130 °C for 20 min.

[0228] A mixture of quantum dot material and crosslinking agent is spin-coated onto the hole transport layer 14, or quantum dots with photosensitive ligands are spin-coated. Ultraviolet light irradiation causes the quantum dots at the positions corresponding to the second light-emitting device 102 emitting red light to crosslink, and this portion is used to form the quantum dot light-emitting layer 13 of the second light-emitting device 102 emitting red light. Then, the quantum dot material and crosslinking agent at the positions of the second light-emitting device 102 and the first light-emitting device 101 emitting green light are removed using solvent development of the quantum dot material.

[0229] A mixture of quantum dot material and crosslinking agent is spin-coated onto the hole transport layer 14, or quantum dots with photosensitive ligands are spin-coated. Ultraviolet light irradiation causes the quantum dots at the positions corresponding to the green light-emitting device 102 to crosslink, forming the quantum dot light-emitting layer 13 of the green light-emitting device 102. Then, the quantum dot material and crosslinking agent at the positions of the second light-emitting device 102 and the first light-emitting device 101, which emit red light, are removed using solvent development of the quantum dot material.

[0230] A mixture of quantum dot material and crosslinking agent is spin-coated onto the hole transport layer 14, or quantum dots with photosensitive ligands are spin-coated. Ultraviolet light irradiation causes the quantum dots corresponding to the positions of the first light-emitting device 101 to crosslink, and this portion is used to form the quantum dot light-emitting layer 13 of the first light-emitting device 101. Then, the quantum dot material and crosslinking agent are removed by solvent development of the quantum dot material to remove the quantum dot material and crosslinking agent corresponding to the positions of the second light-emitting device 102 emitting red light and the second light-emitting device 102 emitting green light.

[0231] Then bake at 100℃ for 5 minutes to form quantum dot luminescent layer 13.

[0232] A mixed solution of PMMA and photosensitive crosslinking agent is spin-coated onto the quantum dot light-emitting layer 13. Through exposure and development, the PMMA corresponding to the positions of the second light-emitting device 102 emitting red light and the second light-emitting device 102 emitting green light is crosslinked and left behind, forming an electron buffer layer 52. The PMMA film at the position of the first light-emitting device 101 is removed during the development process.

[0233] Electron transport layer 15 is formed by spin-coating ZnMgO onto electron buffer layer 52, with a thickness of 50 nm, and then baked at 80 °C for 10 min.

[0234] The substrate with the above-mentioned film layer was placed in an evaporation machine to deposit Al electrodes under a vacuum degree of 1×10⁻⁶. -6 mbar, evaporation rate is The film thickness is 100 nm.

[0235] The above-mentioned device is encapsulated using a glass cover and UV-curable adhesive to obtain a display panel 100.

[0236] Example 5

[0237] The structure of the display panel 100 is as follows: Figure 8 As shown, a hole buffer layer 51 is disposed between the quantum dot light-emitting layer 13 and the hole transport layer 14 of the first light-emitting device 101 emitting blue light, and an electron buffer layer 52 is disposed between the quantum dot light-emitting layer 13 and the electron transport layer 15 of the second light-emitting device 102 emitting red light and the second light-emitting device 102 emitting green light. The method for fabricating the display panel is as follows.

[0238] The ITO substrate was ultrasonically cleaned with deionized water and isopropanol for 15 minutes each, then dried with nitrogen and baked at 135°C for 5 minutes.

[0239] The ITO substrate was treated with ultraviolet ozone for 10 minutes to further clean the organic contaminants attached to the ITO surface and passivate the ITO surface defects.

[0240] PEDOT:PSS material was spin-coated onto an ITO substrate to form a hole injection layer with a thickness of 25 nm, and then baked at 130 °C for 20 min.

[0241] TFB material was spin-coated onto the hole injection layer to form a hole transport layer 14 with a thickness of 20 nm, and then baked at 130 °C for 20 min.

[0242] A mixed solution of PMMA and a photosensitive crosslinking agent is spin-coated onto the hole transport layer 14. Through exposure and development, the PMMA at the location where the first light-emitting device 101 is to be formed is chemically bonded to the photosensitive crosslinking agent, forming a crosslinked network to obtain the hole buffer layer 51. The PMMA and photosensitive crosslinking agent at the location where the second light-emitting device 102 is to be formed are removed during the development process.

[0243] A mixture of quantum dot material and crosslinking agent is spin-coated, or quantum dots with photosensitive ligands are spin-coated. Ultraviolet light irradiation causes crosslinking of the quantum dots at the positions corresponding to the red-emitting second light-emitting device 102. This portion is used to form the quantum dot light-emitting layer 13 of the red-emitting second light-emitting device 102. Then, the quantum dot material and crosslinking agent at the positions corresponding to the green-emitting second light-emitting device 102 and the first light-emitting device 101 are removed using a solvent-based development method.

[0244] A mixture of quantum dot material and crosslinking agent is spin-coated, or quantum dots with photosensitive ligands are spin-coated. Ultraviolet light irradiation causes crosslinking of the quantum dots at the positions corresponding to the green light-emitting device 102. This portion is used to form the quantum dot light-emitting layer 13 of the green light-emitting device 102. Then, the quantum dot material and crosslinking agent at the positions of the second light-emitting device 102 and the first light-emitting device 101, which emit red light, are removed using solvent development of the quantum dot material.

[0245] A mixture of quantum dot material and crosslinking agent is spin-coated, or quantum dots with photosensitive ligands are spin-coated. Ultraviolet light irradiation causes the quantum dots at the corresponding positions of the first light-emitting device 101 to crosslink, and this portion is used to form the quantum dot light-emitting layer 13 of the first light-emitting device 101. Then, the quantum dot material and crosslinking agent at the positions of the second light-emitting device 102 emitting red light and the second light-emitting device 102 emitting green light are removed by solvent development of the quantum dot material.

[0246] Then bake at 100℃ for 5 minutes to form quantum dot luminescent layer 13.

[0247] A mixed solution of PMMA and photosensitive crosslinking agent is spin-coated onto the quantum dot light-emitting layer 13. Through exposure and development, the PMMA corresponding to the positions of the second light-emitting device 102 emitting red light and the second light-emitting device 102 emitting green light is crosslinked and left behind, forming an electron buffer layer 52. The PMMA film at the position of the first light-emitting device 101 is removed during the development process.

[0248] ZnMgO was spin-coated onto the electron buffer layer 52 to form an electron transport layer 15 with a thickness of 50 nm, and then baked at 80 °C for 10 min.

[0249] The substrate with the above-mentioned film layer was placed in an evaporation machine to deposit Al electrodes under a vacuum degree of 1×10⁻⁶. -6 mbar, evaporation rate is The film thickness is 100 nm.

[0250] The above-mentioned device is encapsulated using a glass cover and UV-curable adhesive to obtain a display panel 100.

[0251] Example 6

[0252] The structure of the display panel 100 is as follows: Figure 7 As shown, an electron enhancement layer 53 is disposed between the quantum dot emitting layer 13 and the electron transport layer 15 of the first light-emitting device 101 emitting blue light, and a hole enhancement layer 54 is disposed between the quantum dot emitting layer 13 and the hole transport layer 14 of the second light-emitting device 102 emitting red light and the second light-emitting device 102 emitting green light. The fabrication method of the display panel is as follows.

[0253] The ITO substrate was ultrasonically cleaned with deionized water and isopropanol for 15 minutes each, then dried with nitrogen and baked at 135°C for 5 minutes.

[0254] The ITO substrate was treated with ultraviolet ozone for 10 minutes to further clean the organic contaminants attached to the ITO surface and passivate the ITO surface defects.

[0255] PEDOT:PSS material was spin-coated onto an ITO substrate to form a hole injection layer with a thickness of 25 nm, and then baked at 130 °C for 20 min.

[0256] TFB material was spin-coated onto the hole injection layer to form a hole transport layer 14 with a thickness of 20 nm, and then baked at 130 °C for 20 min.

[0257] A mixed solution of PVK and a photosensitive crosslinking agent is spin-coated onto the hole transport layer 14. Through exposure and development, the PVK at the positions corresponding to the second light-emitting device 102 emitting red light and the second light-emitting device 102 emitting green light is crosslinked and left behind, forming a crosslinked network to obtain the hole enhancement layer 54, with a thickness d5 of 10 nm. The PVK and photosensitive crosslinking agent at the positions corresponding to the first light-emitting device 101 are removed during the development process.

[0258] A mixture of quantum dot material and crosslinking agent is spin-coated, or quantum dots with photosensitive ligands are spin-coated. Ultraviolet light irradiation causes crosslinking of the quantum dots at the positions corresponding to the red-emitting second light-emitting device 102. This portion is used to form the quantum dot light-emitting layer 13 of the red-emitting second light-emitting device 102. Then, the quantum dot material and crosslinking agent at the positions corresponding to the green-emitting second light-emitting device 102 and the first light-emitting device 101 are removed using a solvent-based development method.

[0259] A mixture of quantum dot material and crosslinking agent is spin-coated, or quantum dots with photosensitive ligands are spin-coated. Ultraviolet light irradiation causes crosslinking of the quantum dots at the positions corresponding to the green light-emitting device 102. This portion is used to form the quantum dot light-emitting layer 13 of the green light-emitting device 102. Then, the quantum dot material and crosslinking agent at the positions of the second light-emitting device 102 and the first light-emitting device 101, which emit red light, are removed using solvent development of the quantum dot material.

[0260] A mixture of quantum dot material and crosslinking agent is spin-coated, or quantum dots with photosensitive ligands are spin-coated. Ultraviolet light irradiation causes the quantum dots at the corresponding positions of the first light-emitting device 101 to crosslink, and this portion is used to form the quantum dot light-emitting layer 13 of the first light-emitting device 101. Then, the quantum dot material and crosslinking agent at the positions of the second light-emitting device 102 emitting red light and the second light-emitting device 102 emitting green light are removed by solvent development of the quantum dot material.

[0261] Then bake at 100℃ for 5 minutes to form quantum dot luminescent layer 13.

[0262] A mixed solution of PFN and photosensitive crosslinking agent is spin-coated onto the quantum dot light-emitting layer 13. Through exposure and development, the PFN and photosensitive crosslinking agent at the positions corresponding to the first light-emitting device 101 are crosslinked and retained to form the electron enhancement layer 53. The PFN and photosensitive crosslinking agent at the positions corresponding to the second light-emitting device 102 emitting red light and the second light-emitting device 102 emitting green light are removed during the development process.

[0263] ZnMgO was spin-coated onto the above film to form an electron transport layer 15 with a film thickness of 50 nm, and then baked at 80 °C for 10 min.

[0264] The substrate with the above-mentioned film layer was placed in an evaporation machine to deposit Al electrodes under a vacuum degree of 1×10⁻⁶. -6 mbar, evaporation rate is The film thickness is 100 nm.

[0265] The above-mentioned device is encapsulated using a glass cover and UV-curable adhesive to obtain a display panel 100.

[0266] Examples 1 to 6 above illustrate methods for manufacturing display panels with different structures, and the embodiments disclosed herein are not limited thereto.

[0267] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A display panel, characterized in that, include: Substrate; Multiple light-emitting devices are located on one side of the substrate; Each of the plurality of light-emitting devices includes: an electrode disposed opposite to each other, and a hole transport layer, a quantum dot light-emitting layer and an electron transport layer disposed between the oppositely disposed electrodes and stacked sequentially; the plurality of light-emitting devices includes: a first light-emitting device and a second light-emitting device, wherein the first light-emitting device is configured to emit blue light and the second light-emitting device is configured to emit either red light or green light. Wherein, at least one of the light-emitting devices further includes: an additional functional layer; the additional functional layer includes at least one of: a hole buffer layer, an electron buffer layer, a hole enhancement layer, and an electron enhancement layer; The hole buffer layer is located between the hole transport layer and the quantum dot light-emitting layer of the first light-emitting device, and the hole buffer layer is configured to reduce the hole transport speed; the electron buffer layer is located between the quantum dot light-emitting layer and the electron transport layer of the second light-emitting device, and the electron buffer layer is configured to reduce the electron transport speed; the hole enhancement layer is located between the hole transport layer and the quantum dot light-emitting layer of the second light-emitting device, and the hole enhancement layer is configured to increase the hole transport speed; the electron enhancement layer is located between the quantum dot light-emitting layer and the electron transport layer of the first light-emitting device, and the electron enhancement layer is configured to increase the electron transport speed.

2. The display panel according to claim 1, characterized in that, The material of the hole buffer layer includes any one of the following: polymethyl methacrylate, aluminum oxide, polyvinylpyrrolidone, poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-di-n-octylfluorenyl-2,7-diyl), polyethoxyethyleneimine, poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-di-n-octylfluorenyl-2,7-diyl)-bromo], and naphthalimide.

3. The display panel according to claim 1, characterized in that, The material of the hole buffer layer includes: a first crosslinking material, which is formed by crosslinking a first material with a photosensitive crosslinking agent through a hydrocarbon insertion reaction; the first material includes: any one of polymethyl methacrylate, poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-bis-n-octylfluorenyl-2,7-diyl) and polyvinylpyrrolidone.

4. The display panel according to claim 3, characterized in that, The photosensitive crosslinking agent includes any one of the following: diazacyclopropylene, triazaene, sulfonyl azide, phenyl azide, perfluoroalkyl azide, bipyridine ruthenium, and iridium complexes.

5. The display panel according to claim 1, characterized in that, The thickness of the hole buffer layer ranges from 5 nm to 8 nm.

6. The display panel according to claim 1, characterized in that, The material of the electron buffer layer includes: a second crosslinking material, which is formed by crosslinking a second material with a photosensitive crosslinking agent through a hydrocarbon insertion reaction; the second material includes: polymethyl methacrylate, polyvinylpyrrolidone, poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4′-(N-(4-sec-butylphenyl)diphenylamine)] and poly(9,9-n-dioctyl-2,7-fluorene-alt-9-isooctyl-3,6-carbazole).

7. The display panel according to claim 1, characterized in that, The thickness of the electron buffer layer ranges from 5 nm to 8 nm.

8. The display panel according to claim 1, characterized in that, The hole reinforcement layer comprises a third crosslinking material, which is formed by crosslinking a third material with a photosensitive crosslinking agent through a hydrocarbon insertion reaction; the third material comprises any one of polyvinylcarbazole, 4,4,4,-tris(carbazole-9-yl)triphenylamine, N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine, and 4,4'-bis(N-carbazole)biphenyl.

9. The display panel according to claim 1, characterized in that, The thickness of the hole enhancement layer ranges from 8 nm to 12 nm.

10. The display panel according to claim 1, characterized in that, The material of the electron enhancement layer includes: a fourth crosslinking material, which is formed by crosslinking the fourth material with a photosensitive crosslinking agent through a hydrocarbon insertion reaction; the fourth material includes: any one of poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-di-n-octylfluorenyl-2,7-diyl), poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)fluorenyl-2,7-diyl)-alt-[(9,9-di-n-octylfluorenyl-2,7-diyl)-bromo] and polyethoxyethyleneimine.

11. The display panel according to claim 1, characterized in that, The thickness of the electron enhancement layer ranges from 3 nm to 5 nm.

12. The display panel according to claim 1, characterized in that, The surface of the electrode on the side of the first light-emitting device away from the substrate is not flush with the surface of the electrode on the side of the second light-emitting device away from the substrate.

13. The display panel according to claim 12, characterized in that, The distance between the surface of the electrode of the first light-emitting device on the side away from the substrate and the surface of the electrode of the second light-emitting device on the side away from the substrate in a first direction is in the range of 5nm to 8nm; wherein, the first direction is perpendicular to the substrate.

14. A display device, characterized in that, include: The display panel as described in any one of claims 1 to 13; A driver chip is used to drive the display panel to display.

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