Light-emitting device and manufacturing method thereof

Abstract

The invention discloses a light-emitting device and a manufacturing method thereof, and the method comprises the steps: introducing a modification layer comprising an electron donor above a second electrode, enabling the modification layer to enable the electron donor to be transmitted to an electron transmission layer through heating, ultraviolet irradiation or ionization treatment, namely, enabling the modification layer to provide the electron donor to the electron transmission layer, and enabling the electron donor to be transmitted to the electron transmission layer; as the radius of the electron donor is small and is generally smaller than 70pm, the electron donor can enter a metal atom lattice of the second electrode firstly and is released to the electron transport layer through channels such as defects and dislocation in metal, so that the electron current density in the light-emitting device is improved, the conductivity of the electron transport layer is improved, and the light-emitting efficiency of the light-emitting device is improved. Therefore, the working voltage of the light-emitting device is reduced, Joule heat generated in the light-emitting device is reduced, and the service life of the light-emitting device is greatly prolonged.

Description

Technical Field

[0001] This invention relates to the field of display technology, and in particular to a light-emitting device and its manufacturing method. Background Technology

[0002] Quantum dots (QDs), also known as nanocrystals, are nanoparticles composed of group II-VI or III-V elements, and have advantages such as high quantum yield, narrow emission peak, tunable emission spectrum, and high photochemical stability.

[0003] With the in-depth development of quantum dot preparation technology, the stability and luminous efficiency of quantum dots have been continuously improved. The research on quantum light-emitting diodes (QLEDs) has been deepening. QLEDs have advantages such as self-illumination, low power consumption, and high color gamut, and have received widespread attention from the academic and industrial communities. The application prospects of QLEDs in the display field are becoming increasingly bright. Summary of the Invention

[0004] This invention provides a light-emitting device and its fabrication method, which improves the lifespan of the light-emitting device. The specific solution is as follows:

[0005] An embodiment of the present invention provides a light-emitting device, comprising: a substrate, a first electrode, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer, a second electrode, and a modification layer disposed on the substrate; wherein the material of the modification layer is different from the material of the electron transport layer, both the modification layer and the electron transport layer include electron donors, and the concentration of electron donors in the modification layer is less than the concentration of electron donors in the electron transport layer.

[0006] Optionally, in the light-emitting device provided in the embodiments of the present invention, the material of the modification layer includes at least one of the following: silicon nitride, high-porosity nanoporous material, metal-organic framework material, and polymer material rich in protonated hydrogen, boron, and nitrogen.

[0007] Optionally, in the light-emitting device provided in the embodiments of the present invention, the high-porosity nanoporous material includes at least one of carbon nanotubes and graphene.

[0008] Optionally, in the light-emitting device provided in the embodiments of the present invention, the metal-organic framework material includes at least one of MOF-5(Zn), MOF-177, and COF-5.

[0009] Optionally, in the light-emitting device provided in the embodiments of the present invention, the polymer material rich in protonated hydrogen, boron, and nitrogen includes at least one of boron-nitrogen heterocyclic aromatic hydrocarbons, pyrolytic boron nitride, and hexagonal boron nitride.

[0010] Optionally, in the light-emitting device provided in the embodiments of the present invention, the ratio between the concentration of the electron donor in the modification layer and the concentration of the electron donor in the electron transport layer is 1 / 100 to 1 / 10.

[0011] Optionally, in the light-emitting device provided in the embodiments of the present invention, the thickness of the modification layer is 300-800 nm.

[0012] Optionally, in the light-emitting device provided in the embodiments of the present invention, the thickness of the second electrode is 80-200 nm.

[0013] Accordingly, embodiments of the present invention also provide a method for manufacturing a light-emitting device, used to manufacture the light-emitting device provided in the embodiments of the present invention, the method comprising:

[0014] A first electrode, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer, a second electrode, and a modification layer are formed on a substrate; wherein the material of the modification layer is different from the material of the electron transport layer, and the modification layer includes an electron donor;

[0015] The modified layer is processed to allow electron donors from the modified layer to be transferred to the electron transport layer; wherein the concentration of electron donors in the modified layer is less than the concentration of electron donors in the electron transport layer.

[0016] Optionally, in the manufacturing method provided in the embodiments of the present invention, the processing of the modification layer specifically includes:

[0017] The modified layer is subjected to heating, ultraviolet light irradiation, or ionization treatment.

[0018] Optionally, in the fabrication method provided in the embodiments of the present invention, the concentration of electron donors in the modified layer is greater than 10 before processing the modified layer. 20 cm -3 .

[0019] The beneficial effects of the embodiments of the present invention are as follows:

[0020] This invention provides a light-emitting device and its fabrication method. By introducing a modification layer including electron donors above a second electrode, the modification layer can facilitate the transfer of electron donors to an electron transport layer through heating, ultraviolet irradiation, or ionization. In other words, the modification layer can provide electron donors to the electron transport layer. Since the radius of the electron donors is small, generally less than 70 pm, they can first enter the metal atomic lattice of the second electrode and release electron donors to the electron transport layer through defects, dislocations, and other channels in the metal. This increases the electron current density in the light-emitting device, increases the conductivity of the electron transport layer, and consequently reduces the operating voltage of the light-emitting device, reduces the generation of Joule heat inside the light-emitting device, and thus significantly improves the lifespan of the light-emitting device. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a light-emitting device provided in an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the structure of another light-emitting device provided in an embodiment of the present invention;

[0023] Figure 3 For the reference device (without a modification layer) and the present invention Figure 1 The diagram shows a comparison of the operating voltage (in volts) and current (in milliamperes per square centimeter) curves of a light-emitting device with a modified layer.

[0024] Figure 4 For the reference device (without a modification layer) and the present invention Figure 1 The diagram shows the lifetime decay curve of a light-emitting device with a modified layer.

[0025] Figure 5 The image shows the luminescence morphology of the reference device (without a modification layer).

[0026] Figure 6 In this invention Figure 1 The image shows the luminescence morphology of the light-emitting device with the modified layer.

[0027] Figure 7 This is a schematic diagram of a method for fabricating a light-emitting device according to an embodiment of the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Furthermore, the embodiments and features in the embodiments of the present invention can be combined with each other without conflict. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "comprising" or "including," and similar terms used in this invention, mean that the element or object preceding the term encompasses the element or object listed following the term and its equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. Terms such as "inner," "outer," "upper," and "lower" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0030] As used in this invention, “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).

[0031] As used in this invention, "parallel," "perpendicular," and "equal" include the described situation and situations that are similar to the described situation, within an acceptable deviation range, 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 the acceptable deviation range for approximate parallelism can be, for example, within 5°; "perpendicular" includes absolute perpendicularity and approximate perpendicularity, where the acceptable deviation range for approximate perpendicularity can also be, for example, within 5°. "Equal" includes absolute equality and approximate equality, where the acceptable deviation range for approximate equality can be, for example, the difference between the two equals being less than or equal to 10% of either one.

[0032] 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.

[0033] This invention describes exemplary embodiments with reference to cross-sectional views and / or plan views as idealized exemplary drawings. In the drawings, for clarity, the thickness of layers and the area of ​​regions are enlarged. 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 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 areas of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0034] In this invention, circles, triangles, rectangles, trapezoids, pentagons, or hexagons are not strictly defined, but can be approximate circles, triangles, rectangles, trapezoids, pentagons, or hexagons. Small deformations due to tolerances are possible, and chamfers, curved edges, and other deformations are possible.

[0035] Currently, among the functional materials of QLED devices, hole injection and hole transport materials are mostly polymer materials, while quantum dot light-emitting materials and electron transport materials are nanocrystals. These materials generally have low thermal conductivity. During long-term operation, the Joule heat generated by the device accumulates and cannot be discharged in time, causing accelerated aging and degradation of the device, or even serious device failure, ultimately resulting in a short device lifespan.

[0036] To improve the lifespan of light-emitting devices, embodiments of the present invention provide a light-emitting device, such as... Figure 1 As shown, it includes: a substrate 1, a first electrode 2, a hole injection layer 3, a hole transport layer 4, a quantum dot light-emitting layer 5, an electron transport layer 6, a second electrode 7, and a modification layer 8 disposed on the substrate 1; wherein, the material of the modification layer 8 is different from the material of the electron transport layer 6, and both the modification layer 7 and the electron transport layer 6 include electron donors, and the concentration of electron donors in the modification layer 7 is less than the concentration of electron donors in the electron transport layer 6.

[0037] The light-emitting device provided in this embodiment of the invention can be a positive structure, wherein the first electrode 2, hole injection layer 3, hole transport layer 4, quantum dot light-emitting layer 5, electron transport layer 6, second electrode 7, and modification layer 8 are sequentially stacked on a substrate 1, with the first electrode 2 being the anode and the second electrode 7 being the cathode. This invention introduces a modification layer containing electron donors above the second electrode. This modification layer can facilitate the transfer of electron donors to the electron transport layer through heating, ultraviolet irradiation, or ionization. In other words, the modification layer can provide electron donors to the electron transport layer. Since the radius of the electron donors is small, generally less than 70 pm, they can first enter the metal atomic lattice of the second electrode and release them to the electron transport layer through defects, dislocations, and other channels in the metal. This increases the electron current density in the light-emitting device, increases the conductivity of the electron transport layer, and consequently reduces the operating voltage of the light-emitting device, reduces the generation of Joule heat inside the device, and thus significantly improves the lifespan of the light-emitting device.

[0038] In some embodiments, in the light-emitting device provided in the present invention, the material of the modification layer can be a semiconductor material that stores electron donors, such as silicon nitride. The electron donor stored in silicon nitride is proton hydrogen, which can be transported to the electron transport layer by means of heating, ultraviolet irradiation or ionization treatment, thereby improving the conductivity of the electron transport layer.

[0039] In some embodiments, in the light-emitting device provided in the present invention, the material of the modification layer can be a high-porosity nanoporous material, such as at least one of carbon nanotubes and graphene. The electron donor stored in the porous material is proton hydrogen, which can be transported to the electron transport layer by means of heating, ultraviolet light irradiation or ionization treatment, thereby improving the conductivity of the electron transport layer.

[0040] In some embodiments, in the light-emitting device provided in the present invention, the material of the modification layer can be a metal-organic framework material, such as at least one of MOF-5(Zn), MOF-177, and COF-5. The electron donor stored in the organic framework material is proton hydrogen, which can be transported to the electron transport layer by means of heating, ultraviolet light irradiation, or ionization treatment, thereby improving the conductivity of the electron transport layer.

[0041] In some embodiments, in the light-emitting device provided in the present invention, the material of the modification layer can be a polymer material rich in protonated hydrogen, boron, and nitrogen. For example, the polymer material rich in protonated hydrogen, boron, and nitrogen includes at least one of boron-nitrogen heterocyclic aromatic hydrocarbons, pyrolytic boron nitride, and hexagonal boron nitride. Protonated hydrogen, boron, and nitrogen are electron donors and can be transported to the electron transport layer by means of heating, ultraviolet light irradiation, or ionization treatment, thereby improving the conductivity of the electron transport layer.

[0042] In some embodiments of the light-emitting device provided in this invention, after the modification layer is formed on the second electrode and before the modification layer is subjected to heating, ultraviolet irradiation, or ionization treatment, the concentration of electron donors in the modification layer can be greater than 10. 20 cm -3 This concentration can be achieved by heating, ultraviolet light irradiation, or ionization treatment, so that the concentration of electron donors transported to the electron transport layer meets the requirements for improving the conductivity of the electron transport layer.

[0043] In some embodiments of the present invention, in the light-emitting device provided above, after the modification layer is heated, irradiated with ultraviolet light or ionized, the ratio between the concentration of electron donors in the modification layer and the concentration of electron donors in the electron transport layer can be 1 / 100 to 1 / 10. In this way, a large number of electron donors are introduced into the electron transport layer, which increases the electron current density in the light-emitting device, increases the conductivity of the electron transport layer, thereby reducing the operating voltage of the light-emitting device, reducing the generation of Joule heat inside the light-emitting device, and thus greatly improving the lifespan of the light-emitting device.

[0044] In some embodiments, in the light-emitting device provided in the present invention, the thickness of the modification layer can be 300-800 nm, for example, the thickness of the modification layer is 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, etc.

[0045] In some embodiments, in the light-emitting device provided in the present invention, the thickness of the second electrode can be 80 to 200 nm, for example, the thickness of the second electrode is 80 nm, 90 nm, 100 nm, 120 nm, 150 nm, 180 nm, 200 nm, etc.

[0046] Specifically, by controlling the thickness range of the modified layer, the thickness range of the second electrode, and the concentration range of the electron donor before the modified layer treatment, the electron donor can be diffused into the electron transport layer through the second electrode, thereby improving the conductivity of the electron transport layer.

[0047] In some embodiments, in the light-emitting device provided in the present invention, the measurement method of the electron donor in the modification layer and the electron transport layer may include infrared absorption spectroscopy, XPS, nuclear magnetic resonance, etc. After the electron donor is transported, the spectral peak positions in the corresponding measurement methods of the modification layer and the electron transport layer will change.

[0048] In some embodiments, in the light-emitting device provided in the present invention, the material of the second electrode can be a metal material such as Al, Ag, Au, or an alloy material such as Mg / Ag or Ti / Cr.

[0049] In some embodiments, the packaged light-emitting device is generally subjected to an electrical aging process by applying voltage for a period of time. This electrical aging process can accelerate the interaction between the electron donor and the electron transport material, which is more conducive to the stability of the light-emitting device.

[0050] In some embodiments, the light-emitting devices provided in this invention can be divided into monochrome light-emitting devices and full-color light-emitting devices. The monochrome light-emitting devices can be red light-emitting devices, green light-emitting devices, and blue light-emitting devices, while the full-color light-emitting devices include red light-emitting devices, green light-emitting devices, and blue light-emitting devices.

[0051] In some embodiments, in the light-emitting device provided in the present invention, the substrate can be a rigid substrate or a flexible substrate. The rigid substrate can be a glass substrate or a PMMA (polymethyl methacrylate) substrate, and the flexible substrate can be a PET (polyethylene terephthalate) substrate or a PI (polyimide) substrate.

[0052] In some embodiments, in the light-emitting device provided in the present invention, the material of the first electrode can be ITO / Ag / ITO, and the material of the cathode can be a thin Ag, magnesium silver (Mg:Ag) alloy semi-transparent reflective film layer.

[0053] In some embodiments, in the light-emitting device provided in the present invention, the material of the hole injection layer can be PEDOT, NiOx, MoOx, WOx, V2O5, CuSCN, etc., and the present invention does not limit it.

[0054] In some embodiments, in the light-emitting device provided in the present invention, the material of the hole transport layer may be at least one of poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) (TFB), poly(N-vinylcarbazole) (PVK), and poly(4-phenyl)(4-butylphenyl)amine) (Poly-TPD).

[0055] In some embodiments, in the light-emitting device provided in the present invention, the material of the electron transport layer can be nanoparticles such as ZnO and ZnMgO, and the present invention does not limit this.

[0056] In some embodiments, in the light-emitting device provided in the present invention, the quantum dot light-emitting layer includes a quantum dot material, which may include a quantum dot body and a quantum dot ligand, and the quantum dot body and the coordinating groups in the quantum dot ligand are connected by chemical bonds.

[0057] Optionally, the quantum dot body includes any one of the following: group IIB-VIA quantum dots, group IIIA-VA quantum dots, group IVA-VIA quantum dots, core-shell structured quantum dots, and ABX3 type perovskite quantum dots. In ABX3 type perovskite quantum dots, A is CH3NH3. + (methylamine), NH2CH=NH2 (formamidinium) and Cs + One or more of them, where B is Pb 2+ and Sn 2+ One or two of them, X is Cl - ,Br - and I - One or more of the following, ABX3 type perovskite quantum dots include CH3NH3PbBr3, CH3NH3PbCl3, CH3NH3PbI3, CsPbBr3, CsPbCl3 and CsPbI3.

[0058] For example, group IIB-VIA quantum dots are selected from: one or more binary compounds such as CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, and MgS; and ternary compounds such as CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, and CdZn Te, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, or mixtures thereof; and quaternary compounds such as HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, or mixtures thereof, but not limited thereto.

[0059] IIIA-VA group quantum dots are selected from: binary compounds such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, or mixtures thereof; ternary compounds such as GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, or mixtures thereof; and quaternary 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.

[0060] Group IVA-VIA quantum dots are selected from: binary compounds such as SnS, SnSe, SnTe, PbS, PbSe, PbTe, or mixtures thereof; ternary compounds such as SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, or mixtures thereof; and quaternary compounds such as SnPbSSe, SnPbSeTe, SnPbSTe, or mixtures thereof, but are not limited thereto. Group IVA-VIA quantum dots are selected from, for example, 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.

[0061] A core-shell quantum dot is a quantum dot in which one material forms the core and the other forms the shell. For example, a CdS / ZnS quantum dot means that the core is made of CdS and the shell is made of ZnS.

[0062] In other embodiments, the quantum dot bulk can be other nanoscale materials, such as nanorods, nanosheets, etc. The composition of these other nanoscale materials may include at least one of the following: CdS, CdSe, CdTe, ZnSe, InP, PbS, CuInS2, ZnO, CsPbCl3, CsPbBr3, CsPhI3, CdS / ZnS, CdSe / ZnS, ZnSe, InP / ZnS, PbS / ZnS, InAs, InGaAs, InGaN, GaNk, ZnTe, Si, Ge, and C.

[0063] For example, the quantum dot body can include cadmium-free (Cd) quantum dots. Cadmium-free quantum dots are quantum dots that do not contain cadmium (Cd). Cadmium (Cd) can cause serious environmental / health problems, so cadmium-free quantum dots can be used effectively.

[0064] Quantum dot materials can take on various shapes, including but not limited to spheres, spherical shapes, ellipsoids, polyhedrons, rods, crosses, rings, and other arbitrary geometric shapes.

[0065] In some embodiments, the light-emitting device provided in the present invention may be a quantum dot light-emitting diode or an organic light-emitting diode, but is not limited thereto.

[0066] In some embodiments, the light-emitting device provided in the present invention can also be an inverted structure, such as... Figure 2 As shown, the inverted structure consists of a first electrode 2, a modification layer 8, an electron transport layer 6, a quantum dot light-emitting layer 5, a hole transport layer 4, a hole injection layer 3, and a second electrode 7 sequentially fabricated on a substrate 1. The first electrode 2 is the cathode, and the second electrode 7 is the anode. The material of the modification layer 8 can be as described above. After the electron transport layer 6 is fabricated, the device can be heated, irradiated with ultraviolet light, or ionized to allow the electron donors in the modification layer 8 to be transported to the electron transport layer 6, thereby improving the conductivity of the electron transport layer 6.

[0067] Optionally, the light emission type of the light-emitting device can be a top-emitting structure, a bottom-emitting structure, or a double-sided light-emitting structure.

[0068] like Figure 3 As shown, Figure 3 For the reference device (without a modification layer) and the present invention Figure 1 The schematic diagram showing the comparison of the operating voltage (unit: volts) and current (unit: milliamperes / square centimeter) curves of the light-emitting device with the modified layer can be seen that, under the same current density, the operating voltage of the light-emitting device with the modified layer is significantly reduced. Therefore, the light-emitting device provided in this embodiment of the invention can reduce the operating voltage and reduce the generation of Joule heat inside the light-emitting device, thereby greatly improving the lifespan of the light-emitting device.

[0069] like Figure 4 As shown, Figure 4 For the reference device (without a modification layer) and the present invention Figure 1 The diagram shows the lifetime decay curves of the light-emitting device with the modified layer. The solid line represents the lifetime curve of the reference device, and the dashed line represents the lifetime curve of the light-emitting device with the modified layer of the present invention. It can be seen that the light-emitting device with the modified layer has a longer lifetime.

[0070] above Figure 3and Figure 4 The results show that devices with the modified layer have a longer lifetime, which is more than three times longer than that of the reference device.

[0071] like Figure 5 and Figure 6 As shown, Figure 5 This is a morphology diagram of the light emission of the reference device (without a modification layer). Figure 6 In this invention Figure 1 The light-emitting morphology diagram of the light-emitting device with the modified layer shown in the figure demonstrates that the light-emitting device can still maintain good light-emitting morphology characteristics after the introduction of the modified layer in this invention.

[0072] Based on the same inventive concept, embodiments of the present invention also provide a method for manufacturing a light-emitting device, used to manufacture the light-emitting device as described in the embodiments of the present invention, such as... Figure 7 As shown, the manufacturing method includes:

[0073] S701. A first electrode, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer, a second electrode, and a modification layer are formed on a substrate; wherein the material of the modification layer is different from the material of the electron transport layer, and the modification layer includes an electron donor;

[0074] S702. The modification layer is processed to allow electron donors in the modification layer to be transferred to the electron transport layer; wherein the concentration of electron donors in the modification layer is less than the concentration of electron donors in the electron transport layer.

[0075] In some embodiments, the processing of the modification layer in the above-described manufacturing method provided in this invention specifically includes:

[0076] The modified layer is subjected to heating, ultraviolet light irradiation, or ionization treatment.

[0077] Optionally, the heating temperature can be around 80℃, and the heating time can be around 1 hour.

[0078] Optionally, the wavelength of the ultraviolet light treatment can be 365nm, and the irradiation time can be 2 to 6 minutes.

[0079] Alternatively, ionization treatment can be performed by irradiating with high-energy particle beams such as X-rays at room temperature for 2 to 5 minutes.

[0080] In some embodiments, in the fabrication method provided in the present invention, the concentration of electron donors in the modification layer is greater than 10 before processing the modification layer. 20 cm -3 .

[0081] The following is based on Figure 1Taking the light-emitting device shown as an example, the manufacturing method of the light-emitting device will be described in detail, specifically including the following steps:

[0082] (1) A first electrode is deposited on a substrate, which can be a glass substrate or a PI substrate, and the material of the first electrode can be ITO / Ag / ITO.

[0083] (2) A hole injection layer material is prepared by spin coating on the first electrode. It can be an organic injection material such as PEDOT:PSS, or an inorganic oxide such as MoOx that is vapor-deposited.

[0084] (3) Prepare hole transport layer material by spin coating on hole injection layer. It can be organic hole transport layer such as PVK, TFB, PF8Cz, etc., or it can be vapor-deposited inorganic oxide such as NiOx, VOx, etc.

[0085] (4) A quantum dot light-emitting layer is prepared by spin coating on the hole transport layer. The quantum dot material can be cadmium-based, indium-phosphorus, etc.

[0086] (5) An electron transport layer is prepared by spin coating or magnetron sputtering on the quantum dot light-emitting layer. The electron transport layer can be ZnO nanoparticles or ZnMgO nanoparticles.

[0087] (6) A second electrode is prepared by vapor deposition on the electron transport layer. The material of the second electrode can be Al, and the preferred thickness range of the second electrode is 80-200 nm.

[0088] (7) A silicon nitride thin film is deposited as a modification layer by chemical vapor deposition, and the preferred thickness range of the modification layer is 300-800 nm.

[0089] (8) The light-emitting device prepared in step (7) is heated to a stable temperature of 80°C for 1 hour, and the proton hydrogen electron donor in the modified layer is transferred to the electron transport layer.

[0090] (9) Perform current-voltage performance testing on the light-emitting device after heat treatment in step (8). The starting voltage for the test is set to 0V, and the step size is 0.2V. The test results are as follows: Figure 3 As shown, comparing the current density-voltage curves of the reference device and the device with the modification layer reveals that the modification layer can significantly increase the current density of the device, thereby achieving the goal of reducing the device's operating voltage.

[0091] (10) Perform a lifetime test on the light-emitting device. The test method can be a constant current mode, for example, the current is set to 1.6mA, and the test results are as follows: Figure 4 As shown, the device with the modification layer has a longer lifetime, more than three times that of the reference device.

[0092] (11) Test the luminescence morphology of the light-emitting device, such as... Figure 5 and Figure 6 As shown, the device can still maintain good morphological characteristics after the introduction of the modification layer.

[0093] It should be noted that the methods for depositing the above-mentioned film layers may include blade coating, screen printing, slot coating, roll-to-roll coating, spraying, etc.

[0094] Based on the same inventive concept, embodiments of the present invention also provide a display device, including the light-emitting device described above. The principle by which this display device solves the problem is similar to that of the aforementioned light-emitting device; therefore, the implementation of this display device can refer to the implementation of the aforementioned light-emitting device, and details that are repeated will not be repeated here. This display device can be any product or component with a display function, such as a mobile phone, tablet computer, television, monitor, laptop computer, digital photo frame, or navigator. Other essential components of this display device are understood by those skilled in the art and will not be described in detail here, nor should they be construed as limiting the present invention.

[0095] This invention provides a light-emitting device and its fabrication method. By introducing a modification layer including electron donors above a second electrode, the modification layer can facilitate the transfer of electron donors to an electron transport layer through heating, ultraviolet irradiation, or ionization. In other words, the modification layer can provide electron donors to the electron transport layer. Since the radius of the electron donors is small, generally less than 70 pm, they can first enter the metal atomic lattice of the second electrode and release electron donors to the electron transport layer through defects, dislocations, and other channels in the metal. This increases the electron current density in the light-emitting device, increases the conductivity of the electron transport layer, and consequently reduces the operating voltage of the light-emitting device, reduces the generation of Joule heat inside the light-emitting device, and thus significantly improves the lifespan of the light-emitting device.

[0096] Although preferred embodiments of this disclosure have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this disclosure.

[0097] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this disclosure without departing from the spirit and scope of the embodiments of this disclosure. Therefore, if these modifications and variations to the embodiments of this disclosure fall within the scope of the claims of this disclosure and their equivalents, this disclosure is also intended to include these modifications and variations.

Claims

1. A light emitting device, characterized by, The application relates to a quantum dot light-emitting device, which comprises a substrate, a first electrode, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer, a second electrode and a modification layer arranged on the substrate; wherein the material of the modification layer is different from that of the electron transport layer, the modification layer and the electron transport layer both comprise electron donors, and the concentration of the electron donors in the modification layer is less than that in the electron transport layer. The material of the modification layer comprises at least one of silicon nitride, a high-void nanoporous material, a metal organic framework material, a high-molecular polymer material rich in proton hydrogen, boron and nitrogen.

2. The light emitting device of claim 1, wherein, The high-void nanoporous material comprises at least one of carbon nanotubes and graphene.

3. The light emitting device of claim 2, wherein the first and second light emitting layers are formed of a material having a band gap different from each other. The metal organic framework material comprises at least one of MOF-5 (Zn), MOF-177 and COF-5.

4. The light emitting device of claim 2, wherein the first and second light emitting layers are formed of a material having a band gap different from each other. The high-molecular polymer material rich in proton hydrogen, boron and nitrogen comprises at least one of boron-nitrogen hetero-fused ring aromatic hydrocarbon, pyrolytic boron nitride and hexagonal boron nitride.

5. The light emitting device of claim 2, wherein the first and second light emitting layers are formed of a material having a band gap of 2.5 eV or more. The ratio between the concentration of the electron donors in the modification layer and that in the electron transport layer is 1 / 100-1 / 10.

6. A light emitting device according to any of claims 1-5, c h a r a c t e r i z e d in that The thickness of the modification layer is 300-800 nm.

7. A light emitting device according to any of claims 1-5, c h a r a c t e r i z e d i n that The thickness of the second electrode is 80-200 nm.

8. The light emitting device according to any one of claims 1 to 5, wherein The manufacturing method comprises the following steps:

9. A method for manufacturing a light emitting device as claimed in any one of the claims 1-8, characterized in that forming a first electrode, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer, a second electrode and a modification layer on a substrate; wherein the material of the modification layer is different from that of the electron transport layer, and the modification layer comprises electron donors; processing the modification layer to transfer the electron donors in the modification layer into the electron transport layer; wherein the concentration of the electron donors in the modification layer is less than that in the electron transport layer. The processing of the modification layer specifically comprises the following steps:

10. The manufacturing method as described in claim 9, characterized in that, heating, ultraviolet irradiation or ionization treatment is performed on the modification layer. ​ 11. The manufacturing method as described in claim 9, characterized in that, The concentration of the electron donor of the modification layer is greater than 10 20 cm -3 .

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