Thin film and preparation method thereof, photoelectric device and display device

Abstract

The invention belongs to the technical field of display, and relates to a thin film, which is characterized in that the material of the thin film comprises a first metal oxide and a second metal oxide, and the first metal in the first metal oxide and the second metal in the second metal oxide are the same metal and have different valence states. The invention further relates to a preparation method of the thin film, a photoelectric device and a display device. According to the technical scheme provided by the invention, the transverse conductivity of the film can be improved.

Description

Technical Field

[0001] The present application relates to the field of display technologies, and more specifically, to a thin film, a method for preparing a thin film, a light-emitting device, and a display device. Background Art

[0002] Metal oxides refer to compounds formed by the combination of metal elements and oxygen elements, and are widely used in batteries, optoelectronic devices, supercapacitors, energy storage devices, and magnetic devices. Currently, the performance of thin films prepared using metal oxides still needs to be further improved. Summary of the Invention

[0003] Based on this, embodiments of the present application provide a thin film, a method for preparing the same, an optoelectronic device, and a display device.

[0004] Embodiments of the present application provide a thin film, which adopts the following technical solutions:

[0005] A thin film, wherein the material of the thin film includes a first metal oxide and a second metal oxide, and the first metal in the first metal oxide and the second metal in the second metal oxide are the same metal and have different valence states.

[0006] Further, the first metal in the first metal oxide is selected from one or more of the elements in Group VIB; the second metal in the second metal oxide is selected from one or more of the elements in Group VIB; and / or,

[0007] The valence state of the first metal is 4-6, and the valence state of the second metal is 4-6; and / or,

[0008] The absolute value of the conduction band energy level of the first metal oxide is greater than or equal to 4 eV, and the absolute value of the conduction band energy level of the second metal oxide is greater than or equal to 4 eV; and / or,

[0009] The conductivity of the first metal oxide is greater than or equal to 100 S / cm, and the conductivity of the second metal oxide is greater than or equal to 100 S / cm.

[0010] Further, the valence state of the first metal is higher than that of the second metal. In the thin film, the molar proportion of the first metal oxide is 0%-30%, and the molar proportion of the second metal oxide is 70%-100%.

[0011] Further, the first metal oxide is selected from one or more of MoO3 or WO3; the second metal oxide is selected from one or more of MoO2 or WO2.

[0012] Further, the thin film includes a first sub-layer and a second sub-layer. The material of the first sub-layer includes the first metal oxide and the second metal oxide, and the material of the second sub-layer includes a second material, wherein the refractive index of the second material is greater than or equal to 1.2.

[0013] Further, the second material is selected from one or more of AlQ3, NPB, TPD, TAPC, BDAVBi, 2-TNATA, TPT1, TPBi, Bpy-OXD, and DBFTrz.

[0014] Further, the refractive index of the first sub-layer in the wavelength band of 400 nm to 700 nm is greater than or equal to 1.8; and / or

[0015] the extinction coefficient of the first sub-layer in the wavelength band of 400 nm to 700 nm is less than or equal to 0.05.

[0016] The embodiment of the present application also provides a method for preparing a thin film, which adopts the following technical solutions:

[0017] Provide a first metal oxide and a second metal oxide, deposit the first metal oxide and the second metal oxide to form a thin film;

[0018] Wherein, the first metal in the first metal oxide and the second metal in the second metal oxide are the same metal and have different valence states.

[0019] Further, the step of depositing the first metal oxide and the second metal oxide includes:

[0020] Deposit the first metal oxide and the second metal oxide under a preset pressure to form the thin film.

[0021] Further, the preset pressure is 1×10 -4 Pa to 5×10 -4 Pa; and / or, the step of depositing the first metal oxide and the second metal oxide is specifically: simultaneously deposit the first metal oxide and the second metal oxide at a set co-evaporation rate ratio;

[0022] The set co-evaporation rate ratio is (0 to 1):(2 to 10).

[0023] Further, the thin film includes a first sub-layer and a second sub-layer, and the preparation method includes the following steps:

[0024] Deposit the first metal oxide and the second metal oxide to form the first sub-layer;

[0025] Deposit a second material on the first sub-layer to form the second sub-layer, thereby obtaining the thin film;

[0026] Wherein, the refractive index of the second material is greater than or equal to 1.2.

[0027] The embodiment of the present application also provides an optoelectronic device, which adopts the following technical solution:

[0028] An optoelectronic device includes an anode, a functional layer, and a cathode which are stacked. The optoelectronic device further includes a light extraction layer disposed outside at least one of the anode and the cathode. The light extraction layer includes the thin film as described above.

[0029] Further, the transmittance of the anode or the cathode in the wavelength band of 400 nm to 700 nm is not less than 20%; and / or,

[0030] The material of the anode and / or the cathode includes one or more of metals, carbon materials, and metal oxides. The metals include one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg; the carbon materials include one or more of graphite, carbon nanotubes, graphene, and carbon fibers; the metal oxides include doped or undoped metal oxides, including one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, and AMO, or a composite electrode including a metal sandwiched between doped or undoped transparent metal oxides. The composite electrode includes one or more of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO2 / Ag / TiO2, and TiO2 / Al / TiO2; and / or,

[0031] The functional layer includes a hole functional layer. The hole functional layer includes a hole transport layer and / or a hole injection layer. The material of the hole transport layer and / or the hole injection layer includes at least one of TFB, CuPc, PVK, Poly-TPD, PFB, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, polyaniline, transition metal oxides, transition metal sulfides, transition metal stannides, doped graphene, undoped graphene, and C60; and / or

[0032] The functional layer further includes a light-emitting layer, and the light-emitting layer is a quantum dot light-emitting layer or an organic light-emitting layer; wherein, the material of the quantum dot light-emitting layer includes at least one of single-structure quantum dots and core-shell structure quantum dots, and the materials of the single-structure quantum dots, the core materials of the core-shell structure quantum dots, and the shell materials of the core-shell structure quantum dots are respectively selected from at least one of II-VI group compounds, IV-VI group compounds, III-V group compounds, and I-III-VI group compounds. Among them, the II-VI group compounds include, but are not limited to, one or more of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe; the IV-VI group compounds include, but are not limited to, one or more of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe; the III-V group compounds include, but are not limited to, one or more of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb; the I-III-VI group compounds include, but are not limited to, at least one of CuInS2, CuInSe2, and AgInS2;The materials of the organic light-emitting layer include at least one of 4,4'-bis(N-carbazolyl)-1,1'-biphenyl: tris[2-(p-tolyl)pyridine-C2,N]iridium(III), 4,4',4''-tris(carbazol-9-yl)triphenylamine: tris[2-(p-tolyl)pyridine-C2,N]iridium, diarylanthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPX fluorescent materials, TBRb fluorescent materials, and DBP fluorescent materials, polyacetylene and its derivatives, poly(p-phenylene) and its derivatives, polythiophene and its derivatives, polyfluorene and its derivatives; and / or;

[0033] The functional layer further includes an electron functional layer, and the electron functional layer includes an electron transport layer and / or an electron injection layer. The electron transport layer and / or the electron injection layer includes an inorganic material or an organic material. Among them, the inorganic material is selected from one or more of doped or undoped zinc oxide, barium oxide, aluminum oxide, nickel oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, aluminum zinc oxide, manganese zinc oxide, tin zinc oxide, lithium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc stannide, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, barium titanate. The doped elements include one or more of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, gadolinium. The organic material is selected from one or more of quinoxaline compounds, imidazole compounds, triazine compounds, fluorene-containing compounds, hydroxyquinoline compounds, phosphine oxide compounds.

[0034] The embodiment of the present application also provides a display device, which adopts the following technical solutions:

[0035] A display device, characterized in that the display device includes the optoelectronic device as described above.

[0036] Compared with the prior art, the present application mainly has the following beneficial effects:

[0037] The present application provides a thin film containing a first metal oxide and a second metal oxide. Since the first metal in the first metal oxide and the second metal in the second metal oxide are the same metal and have different valence states, it plays a role in adjusting the conductivity of the thin film, thereby adjusting the lateral conductivity of the thin film. Description of the Drawings

[0038] In order to more clearly illustrate the solutions of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained according to these drawings without creative efforts.

[0039] Figure 1 It is a schematic structural diagram of the thin film according to an embodiment of the present application;

[0040] Figure 2 It is a schematic structural diagram of the optoelectronic device according to an embodiment of the present application.

[0041] Reference numerals:

[0042] 1. Light extraction layer; 11. First sub-layer; 12. Second sub-layer; 2. Anode; 3. Hole functional layer; 31. Hole injection layer; 32. Hole transport layer; 4. Light-emitting layer; 5. Electron functional layer; 6. Cathode. Detailed implementation manners

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the specification and claims of this application or the above drawings are used to distinguish different objects and are not used to describe a specific order.

[0044] Referring to "embodiment" herein means that the specific features, structures or characteristics described in connection with the embodiment can be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0045] Microcavity-enhanced electroluminescent devices have been widely used in small and medium-sized displays such as mobile phones and tablets. The corresponding light emission has high external quantum efficiency and color purity, and can achieve advantages such as flexibility, low power consumption, and wide color gamut.

[0046] In order to improve the light extraction efficiency of electroluminescent devices, the microcavity structures of currently applied organic light-emitting diodes (OLEDs) or quantum dot light-emitting diodes (QLEDs) are composed of a total reflection bottom electrode, a light-emitting functional layer, a semi-reflection top electrode, and a light extraction layer. The commonly used semi-reflection electrode needs to control its thickness to obtain an appropriate transmittance, so as to obtain a better viewing angle. However, the commonly used semi-reflection electrode has a large surface resistance and relatively poor film continuity; at the same time, the conductivity of the existing light extraction layer is weak. In medium and large light-emitting panels, since the electrical signal is often driven from the edge of the panel to the center of the panel, the conductivity of the cathode and the conductivity of the light extraction layer will affect the driving of the cathode signal, resulting in poor brightness uniformity of the light-emitting device.

[0047] Based on the above technical problems, an embodiment of the present application provides a thin film, and the material of the thin film includes a first metal oxide and a second metal oxide.

[0048] In some embodiments, the first metal in the first metal oxide and the second metal in the second metal oxide are the same metal and have different valence states. In this embodiment, one of the first metal and the second metal is in the highest metal state, and the other is in a non-highest metal state.

[0049] An embodiment of the present application provides a thin film including a first metal oxide and a second metal oxide. Since the first metal in the first metal oxide and the second metal in the second metal oxide are the same metal and have different valence states, by adding the metal oxide in the highest metal state, the extinction coefficient of the thin film can be reduced, thereby improving the reflectivity of the thin film and thus improving the light extraction efficiency of the thin film; at the same time, by adding the metal oxide in the non-highest metal state, the conductivity of the thin film can be increased, thereby improving the lateral conductivity of the thin film.

[0050] In some embodiments, the first metal in the first metal oxide is selected from one or more of the elements in Group VIB, and the first metal oxide is a Group VIB oxide; the second metal in the second metal oxide is selected from one or more of the elements in Group VIB, and the second metal oxide is a Group VIB oxide.

[0051] In some embodiments, the absolute value of the conduction band energy level of the first metal oxide is greater than or equal to 4 eV, and the absolute value of the conduction band energy level of the second metal oxide is greater than or equal to 4 eV;

[0052] Both the first metal oxide and the second metal oxide in the embodiment of the present application belong to deep-level wide-bandgap semiconductors (the absolute value of the depth of the conduction band bottom energy level is greater than 4 eV). When the metal oxide is in the non-highest metal state, it can generate bandgap states located at the conduction band edge, which can improve the lateral conductivity of the thin film; in addition, when the thin film is used as the light extraction layer 1 on an optoelectronic device, the first metal oxide and / or the second metal oxide are in contact with the material of the adjacent electrode, and an accumulation-type heterojunction can be generated at the interface between the light extraction layer 1 and the adjacent electrode without an external voltage, and electrons accumulate at the interface. When an external voltage is applied, the external voltage can drive the accumulated electrons to flow, thereby realizing the improvement of the conductivity of the optoelectronic device.

[0053] In some embodiments, the valence state of the first metal is 4 to 6, the valence state of the second metal is 4 to 6, and the absolute value of the conduction band energy level of the first metal oxide needs to be greater than or equal to 4 eV, and the absolute value of the conduction band energy level of the second metal oxide needs to be greater than or equal to 4 eV. Therefore, the first metal and the second metal are molybdenum or tungsten.

[0054] In this embodiment, the valence state of the first metal is higher than that of the second metal;

[0055] When the metal oxide is molybdenum oxide, the first metal oxide is MoO3 with the highest metal state, and the second metal oxide is MoO2 with a non - highest metal state;

[0056] When the metal oxide is tungsten oxide, the first metal oxide is WO3 with the highest metal state, and the second metal oxide is WO2 with a non - highest metal state.

[0057] The thin film in the embodiment of the present application includes a first metal oxide with the highest metal state to reduce the extinction coefficient of the thin film and improve the reflectivity of the thin film; it also includes a second metal oxide with a non - highest metal state, which plays a role in improving the conductivity of the thin film, thereby improving the lateral conductivity of the thin film.

[0058] In some embodiments, the molar proportion of the first metal oxide is 0% to 30%, and the molar proportion of the second metal oxide is 70% to 100%. Specifically, in the material of the thin film, the molar proportion of the first metal oxide is 0%, and the molar proportion of the second metal oxide is 100%; or, in the material of the thin film, the molar proportion of the first metal oxide is 10%, and the molar proportion of the second metal oxide is 90%; or, in the material of the thin film, the molar proportion of the first metal oxide is 20%, and the molar proportion of the second metal oxide is 80%; or, in the material of the thin film, the molar proportion of the first metal oxide is 30%, and the molar proportion of the second metal oxide is 70%.

[0059] In the embodiment of the present application, by adjusting the molar proportion of the first metal oxide in the material of the thin film, the conductivity and extinction coefficient of the thin film can be adjusted, thereby enhancing the lateral conductivity of the thin film and improving the light extraction efficiency of the thin film.

[0060] In some embodiments, the conductivity of the first metal oxide is greater than or equal to 100 S / cm, and the conductivity of the second metal oxide is greater than or equal to 100 S / cm.

[0061] Please refer to Figure 1As shown, in this embodiment, the thin film includes a first sub-layer 11 and a second sub-layer 12. The material of the first sub-layer 11 includes the first metal oxide and the second metal oxide, and the material of the second sub-layer 12 includes a high refractive index material. Wherein, the refractive index of the high refractive index material is greater than or equal to 1.2.

[0062] In the embodiment of the present application, by further providing a second sub-layer 12 on the first sub-layer 11, and the second sub-layer 12 uses a high refractive index material, the angle dependence problem caused by the microcavity structure in the thin film is weakened.

[0063] In some embodiments, the refractive index of the first sub-layer 11 in the wavelength band of 400nm to 700nm is greater than or equal to 1.8, and the refractive index of the first sub-layer 11 in the wavelength band of 400nm to 700nm is less than or equal to 0.05.

[0064] In some embodiments, the thickness of the first sub-layer 11 is 20nm to 200nm. For example: the thickness of the first sub-layer 11 is any value among 20nm, 50nm, 100nm, 150nm, 200nm or the range formed between any two values.

[0065] In some embodiments, the material of the second sub-layer 12 is selected from at least one of AlQ3, NPB, TPD, TAPC, BDAVBi, 2-TNATA, TPT1, TPBi, Bpy-OXD, DBFTrz.

[0066] In some embodiments, the thickness of the second sub-layer 12 is 10nm to 200nm. Specifically, the thickness of the second sub-layer 12 can be set to any value among 10nm, 20nm, 50nm, 100nm, 150nm, 200nm or the range formed between any two values.

[0067] Based on the above thin film, the embodiment of the present application also provides a method for preparing a thin film, which is used to prepare the thin film as described above, and includes the following steps:

[0068] Provide the first metal oxide and the second metal oxide, deposit the first metal oxide and the second metal oxide to obtain a thin film.

[0069] In some embodiments, the first metal in the first metal oxide and the second metal in the second metal oxide are the same metal and have different valence states. In this embodiment, the first metal has the highest metal state, and the second metal has a non-highest metal state.

[0070] The method for preparing a thin film provided by the embodiments of the present application deposits a first metal oxide and a second metal oxide having the same metal but different metal states to form a thin film. By adding the second metal oxide with a lower valence state, the conductivity of the thin film is enhanced, thereby improving the lateral conductivity of the thin film. At the same time, by adding the first metal oxide with a higher metal state, the extinction coefficient of the thin film is reduced, and the reflectivity of the thin film is increased, thereby improving the light extraction efficiency of the thin film. Thus, by simultaneously adding the first metal oxide with a higher valence state and the second metal oxide with a lower valence state, the conductivity and extinction coefficient of the thin film can be better adjusted simultaneously to meet the application requirements of more scenarios.

[0071] In some embodiments, the step of depositing the first metal oxide and the second metal oxide includes:

[0072] Under a set negative pressure, the first metal oxide and the second metal oxide are simultaneously deposited at a set co-evaporation rate ratio to form the thin film.

[0073] In some embodiments, the set negative pressure is 1×10 -4 Pa to 5×10 -4 Pa. Specifically, the set negative pressure can be set to any value of 1×10 -4 Pa, 2×10 -4 Pa, 3×10 -4 Pa, 4×10 -4 Pa, 5×10 -4 Pa or a range formed between any two values.

[0074] In some embodiments, the set co-evaporation rate ratio is (0 to 1):(2 to 10). Specifically, when the set co-evaporation rate ratio is 0:10 (i.e., only the second metal oxide is deposited), the molar proportion of the second metal oxide in the material of the thin film is 100%; when the set co-evaporation rate ratio is 1:10, the molar proportion of the first metal oxide in the material of the thin film is 10%, and the molar proportion of the second metal oxide is 90%; when the set co-evaporation rate ratio is 1:5, the molar proportion of the first metal oxide in the material of the thin film is 20%, and the molar proportion of the second metal oxide is 80%; when the set co-evaporation rate ratio is 1:2, the molar proportion of the first metal oxide in the material of the thin film is 30%, and the molar proportion of the second metal oxide is 70%.

[0075] In the embodiments of the present application, by adjusting the molar proportion of the first metal oxide in the material of the thin film, the conductivity and extinction coefficient of the thin film are adjusted, thereby enhancing the lateral conductivity of the thin film and improving the light extraction efficiency of the thin film.

[0076] In some embodiments, the thin film includes a first sub-layer and a second sub-layer, and the preparation method includes the following steps:

[0077] Deposit the first metal oxide and the second metal oxide to form the first sub-layer;

[0078] Deposit a high refractive index material on the first sub-layer to form the second sub-layer, obtaining the thin film.

[0079] In the embodiments of the present application, by further providing a second sub-layer on the first sub-layer, and the second sub-layer uses a material with a high refractive index, the angle dependence problem caused by the microcavity structure in the thin film is weakened.

[0080] Please refer to Figure 2 As shown, based on the above thin film and the preparation method of the thin film, the embodiments of the present application further provide an optoelectronic device, which has a light extraction layer 1, wherein the light extraction layer 1 uses the above thin film.

[0081] In some embodiments, the optoelectronic device includes an anode 2, a functional layer, and a cathode 6 which are stacked, and the optoelectronic device further includes a thin film disposed outside at least one of the anode and the cathode, and the thin film includes the thin film as described above.

[0082] In this embodiment, the optoelectronic device emits light from the cathode 6 side, and the thin film is disposed on the cathode 6 as the light extraction layer 1.

[0083] The functional layer includes a hole functional layer 3, a light emitting layer 4, and an electron functional layer 5 which are stacked. Among them, the hole functional layer 3 includes a hole injection layer 31 and a hole transport layer 32 which are stacked. In the optoelectronic device provided in the embodiments of the present application, by disposing the above thin film on the cathode 6 as the light extraction layer 1, due to the relatively high conductivity of the thin film itself, it plays a role in improving the difference between the edge potential and the center potential of the cathode 6, improving the conduction uniformity on the cathode 6, thereby improving the light emission uniformity of the optoelectronic device; by using the first metal oxide and the second metal oxide with different metal valences in the first sub-layer 11 of the thin film, it plays a role in improving the surface resistance of the cathode 6, thereby improving the film continuity and conductivity of the cathode 6, achieving the enhancement of the lateral conduction ability of the cathode 6; in addition, by using the characteristic that the first metal oxide and the second metal oxide have a relatively high refractive index in the wavelength band of 400 nm to 700 nm, photons located inside the optoelectronic device can be extracted, thereby improving the light extraction efficiency of the optoelectronic device and improving the performance of the optoelectronic device.

[0084] Please refer to Figure 2As shown, in this embodiment, the light-emitting device is a normal light-emitting device, and the structure of the light-emitting device is anode 2 / hole functional layer 3 / light-emitting layer 4 / electron functional layer 5 / cathode 6 / light extraction layer 1. In other embodiments, the light-emitting device may also be an inverted light-emitting device, and the structure of the light-emitting device is cathode 6 / electron functional layer 5 / light-emitting layer 4 / hole functional layer 3 / anode 2 / light extraction layer 1.

[0085] In some embodiments, the material of the anode 2 and / or the cathode 6 includes at least one of metal, carbon material, and metal oxide. The metal includes at least one of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg; the carbon material includes at least one of graphite, carbon nanotube, graphene, and carbon fiber; the metal oxide includes doped or undoped metal oxide, including at least one of ITO, FTO, ATO, AZO, GZO, IZO, MZO, and AMO, or a composite electrode with a metal sandwiched between doped or undoped transparent metal oxides. The composite electrode includes at least one of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO2 / Ag / TiO2, and TiO2 / Al / TiO2.

[0086] In some embodiments, the hole functional layer 3 includes a hole injection layer 31 and a hole transport layer 32 stacked. The material of the hole injection layer 31 and / or the hole transport layer 32 includes at least one of TFB, CuPc, PVK, Poly-TPD, PFB, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, polyaniline, transition metal oxide, transition metal sulfide, transition metal stannide, doped graphene, undoped graphene, and C60.

[0087] The light-emitting layer 4 is a quantum dot light-emitting layer or an organic light-emitting layer; wherein, the material of the quantum dot light-emitting layer includes at least one of single-structure quantum dots and core-shell structure quantum dots, the material of the single-structure quantum dots, the core material of the core-shell structure quantum dots, and the shell material of the core-shell structure quantum dots are respectively selected from at least one of II-VI group compounds, IV-VI group compounds, III-V group compounds, and I-III-VI group compounds, and the shell layer of the core-shell structure quantum dots includes one or more layers; wherein, the II-VI group compounds include but are not limited to one or more of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe, the IV-VI group compounds include but are not limited to one or more of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe, the III-V group compounds include but are not limited to one or more of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb, and the I-III-VI group compounds include but are not limited to at least one of CuInS2, CuInSe2, and AgInS2;The materials of the organic light-emitting layer include at least one of 4,4'-bis(N-carbazolyl)-1,1'-biphenyl: tris[2-(p-tolyl)pyridine-C2,N]iridium(III), 4,4',4”-tris(carbazol-9-yl)triphenylamine: tris[2-(p-tolyl)pyridine-C2,N]iridium, diarylanthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPX fluorescent materials, TBRb fluorescent materials, and DBP fluorescent materials, polyacetylene and its derivatives, poly(p-phenylene) and its derivatives, polythiophene and its derivatives, polyfluorene and its derivatives.

[0088] The electron function layer 5 includes an electron transport layer and / or an electron injection layer, and the electron transport layer and / or the electron injection layer includes an inorganic material or an organic material; wherein, the inorganic material is selected from one or more of doped or undoped zinc oxide, barium oxide, aluminum oxide, nickel oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, aluminum zinc oxide, manganese zinc oxide, tin zinc oxide, lithium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc stannide, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, barium titanate; the doped elements include one or more of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, gadolinium; the organic material is selected from one or more of quinoxaline compounds, imidazole compounds, triazine compounds, fluorene-containing compounds, hydroxyquinoline compounds, phosphine oxide compounds.

[0089] Based on the above light-emitting device, an embodiment of the present application further provides a display device, and the display device includes the above light-emitting device.

[0090] The display device can be any electronic product with a display function, and the electronic product includes but is not limited to a smart phone, a tablet computer, a notebook computer, a digital camera, a digital video camera, a smart wearable device, a smart weighing electronic scale, a vehicle-mounted display, a television, or an e-book reader. Among them, the smart wearable device can be, for example, a smart bracelet, a smart watch, a virtual reality (VR) helmet, etc.

[0091] The present application will be specifically described below through specific embodiments. The following embodiments are only part of the embodiments of the present application and do not limit the present application.

[0092] Film Example 1

[0093] Step (1), under a vacuum degree of 2*10 -4 Pa, evaporate and deposit a first sub-layer of MoO2:MoO3 with a thickness of 20 nm to obtain a film;

[0094] Among them, the evaporation rate of MoO2 is controlled to The molar mass ratio of MoO2 in the thin film is 70%; the evaporation rate of MoO3 is controlled to be The molar mass ratio of MoO3 in the thin film is 30%.

[0095] Thin film Example 2

[0096] Step ⑴, under a vacuum of 2*10 -4 Pa, evaporate and deposit a first sub-layer of MoO2:MoO3 with a thickness of 20 nm to obtain a thin film;

[0097] Among them, the evaporation rate of MoO2 is controlled to be The molar mass ratio of MoO2 in the thin film is 80%; the evaporation rate of MoO3 is controlled to be The molar mass ratio of MoO3 in the thin film is 20%.

[0098] Thin film Example 3

[0099] Step ⑴, under a vacuum of 2*10 -4 Pa, evaporate and deposit a first sub-layer of MoO2:MoO3 with a thickness of 20 nm to obtain a thin film;

[0100] Among them, the evaporation rate of MoO2 is controlled to be The molar mass ratio of MoO2 in the thin film is 90%; the evaporation rate of MoO3 is controlled to be The molar mass ratio of MoO3 in the thin film is 10%.

[0101] Thin film Example 4

[0102] Step ⑴, under a vacuum of 2*10 -4 Pa, evaporate and deposit a first sub-layer of WO2:WO3 with a thickness of 20 nm to obtain a thin film;

[0103] Among them, the evaporation rate of WO2 is controlled to be The molar mass ratio of WO2 in the thin film is 70%; the evaporation rate of WO3 is controlled to be The molar mass ratio of WO3 in the thin film is 30%.

[0104] Thin film Example 5

[0105] The difference between this example and Thin film Example 1 is that it further includes Step ⑵, under a vacuum of 2*10 -4 Pa, deposit 10 nm thick BDAVBi on the first sub-layer to form a second sub-layer, and obtain a thin film.

[0106] Thin film Comparative Example 1

[0107] Step ⑴, under a vacuum of 2×10 -4 Pa, deposit the first sub-layer of BDAVBi with a thickness of 10 nm by evaporation to obtain a thin film.

[0108] Thin film comparative example 2

[0109] Step ⑴, under a vacuum of 2×10 -4 Pa, deposit the first sub-layer of MoO3 with a thickness of 20 nm by evaporation to obtain a thin film;

[0110] Among them, the evaporation rate of the MoO3 is controlled to be

[0111] Thin film comparative example 3

[0112] Step ⑴, under a vacuum of 2×10 -4 Pa, deposit the first sub-layer of MoO2 with a thickness of 20 nm by evaporation to obtain a thin film;

[0113] Among them, the evaporation rate of the MoO2 is controlled to be

[0114] Analysis of thin film test results:

[0115] Place the thin films prepared in thin film examples 1 to 5 and thin film comparative examples 1 to 3 on the electrode layer as the light extraction layer, and use the four-probe test method to measure the sheet resistance. The test results are shown in Table 1.

[0116] Sheet Resistance (Ω / sq) Thin Film Example 1 11.9 Thin Film Example 2 11.5 Thin Film Example 3 10.7 Thin Film Example 4 12.0 Thin Film Example 5 11.9 Thin Film Comparative Example 1 12.1 Thin Film Comparative Example 2 12.1 Thin Film Comparative Example 3 10.2

[0117] Table 1

[0118] By comparing the test results of thin film examples 1 to 5 and thin film comparative examples 2 to 3 with those of thin film comparative example 1 respectively, it can be known that the thin films prepared with metal oxides can effectively reduce the sheet resistance.

[0119] By comparing the test results of thin film examples 1 to 3 with those of thin film comparative example 2 and thin film comparative example 3, it can be known that as the molar ratio of MoO2 (the second metal oxide with a lower valence state) in the thin film gradually increases, the sheet resistance gradually decreases and the conductivity of the thin film gradually increases.

[0120] According to the comparative analysis of the above thin film test results, it can be known that the thin films prepared with the first metal oxide and the second metal oxide having the same metal but different metal valences in the embodiments of the present application can effectively improve the lateral conductivity of the thin film and play a role in improving the surface resistance of the electrode layer.

[0121] Optoelectronic device example 1

[0122] Step ⑴: Provide an anode substrate (ITO / Ag / ITO). After cleaning the anode substrate, treat it for 15 minutes under ultraviolet irradiation.

[0123] Step ⑵: Deposit a 25-nm-thick PEDOT:PSS on the treated anode substrate and bake it at 150 °C for 20 minutes in an air atmosphere to form a hole injection layer.

[0124] Step ⑶: Deposit a 20-nm-thick TFB on the hole injection layer and bake it at 180 °C for 60 minutes in a nitrogen environment to form a hole transport layer.

[0125] Step ⑷: Deposit 60 nm of PVK:Ir(piq)2(acac) on the hole transport layer and bake it at 140 °C for 10 minutes to form a light-emitting layer.

[0126] Step ⑸: Evaporate a 40-nm-thick mixture of TPBi:Liq (evaporation rate ratio = 1:1) on the light-emitting layer to form an electron transport layer.

[0127] Step ⑹: Evaporate 1 nm of Yb on the electron transport layer to form an electron injection layer.

[0128] Step ⑺: Evaporate a 10-nm-thick Mg:Ag alloy on the electron injection layer to form a cathode. Among them, the weight ratio of Mg:Ag is 1:9, and the evaporation rates of the two are respectively controlled as and

[0129] Step ⑻: Use the preparation method of the above thin film Example 1 to form a thin film on the cathode as a light extraction layer.

[0130] Optoelectronic device Example 2

[0131] The difference between this example and Optoelectronic device Example 1 is that in Step ⑻, use the preparation method of the above thin film Example 2 to form a thin film on the cathode as a light extraction layer.

[0132] Optoelectronic device Example 3

[0133] The difference between this example and Optoelectronic device Example 1 is that in Step ⑻, use the preparation method of the above thin film Example 3 to form a thin film on the cathode as a light extraction layer.

[0134] Optoelectronic device Example 4

[0135] The difference between this example and Optoelectronic device Example 1 is that in Step ⑻, use the preparation method of the above thin film Example 4 to form a thin film on the cathode as a light extraction layer.

[0136] Optoelectronic device Example 5

[0137] The difference between this embodiment and Embodiment 1 of the optoelectronic device is that in step (8), the film is formed on the cathode by using the preparation method of the above-mentioned Film Embodiment 5 as the light extraction layer.

[0138] Optoelectronic Device Comparative Example 1

[0139] The difference between this comparative example and Embodiment 1 of the optoelectronic device is that in step (8), the film is formed on the cathode by using the preparation method of the above-mentioned Film Comparative Example 1 as the light extraction layer.

[0140] Optoelectronic Device Comparative Example 2

[0141] The difference between this comparative example and Embodiment 1 of the optoelectronic device is that in step (8), the film is formed on the cathode by using the preparation method of the above-mentioned Film Comparative Example 1 as the light extraction layer.

[0142] Optoelectronic Device Comparative Example 3

[0143] The difference between this embodiment and Embodiment 1 of the optoelectronic device is that in step (8), the film is formed on the cathode by using the preparation method of the above-mentioned Film Comparative Example 1 as the light extraction layer.

[0144] Optoelectronic Device Test Structure Analysis

[0145] The optoelectronic devices separately prepared from Embodiments 1 to 5 of the optoelectronic device and Comparative Examples 1 to 3 of the optoelectronic device were tested for the driving voltage (current density: 10 mA / cm2) and current efficiency (optoelectronic device at 1000 nit brightness) by using an IVL test device, and the test results are shown in Table 2.

[0146]

[0147]

[0148] Table 2

[0149] From the test results of the driving voltages of Embodiments 1 to 5 of the optoelectronic device and Comparative Examples 1 to 3 of the optoelectronic device, it can be known that since the size of the optoelectronic device is small, the driving voltage hardly changes.

[0150] From the test results of comparing Embodiments 1 to 5 of the optoelectronic device with Comparative Example 1 of the light-emitting device, it can be known that by forming a film prepared by using a first metal oxide and a second metal oxide having the same metal and different metal valences on the cathode as the light extraction layer, the current efficiency of the optoelectronic device can be improved.

[0151] By comparing the test results of the current efficiency of Examples 1-4 of optoelectronic devices with Comparative Example 2 and Comparative Example 3 of optoelectronic devices, it can be known that as the molar ratio of MoO2 gradually increases, the current efficiency of optoelectronic devices gradually decreases. Since the refractive index of MoO2 is lower than that of MoO3, the light extraction efficiency of optoelectronic devices gradually decreases.

[0152] In summary, according to the comparative analysis of thin film test results and the comparative analysis of optoelectronic device test results, it can be known that by setting a thin film prepared with a first metal oxide and a second metal oxide having the same metal but different metal valences on the cathode as the light extraction layer, it can improve the surface electrode of the electrode layer, and can improve the film continuity and conductivity of the electrode layer, improve the light extraction efficiency of optoelectronic devices, and improve device performance. Among them, when the molar ratio of the low-valence metal oxide in the thin film is 80% and the molar ratio of the high-valence metal oxide is 20%, the improvement effect of the thin film on the electrode layer is the best.

[0153] Obviously, the embodiments described above are only a part of the embodiments of the present application, rather than all the embodiments. The preferred embodiments of the present application are given in the drawings, but do not limit the patent scope of the present application. The present application can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosed content of the present application more thorough and comprehensive. Although the present application has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing specific embodiments, or perform equivalent replacements for some of the technical features. Any equivalent structure using the content of the specification and drawings of the present application, directly or indirectly applied in other related technical fields, is similarly within the scope of patent protection of the present application.

Claims

1. A film, characterized in that, The material of the thin film includes a first metal oxide and a second metal oxide, and the first metal in the first metal oxide and the second metal in the second metal oxide are the same metal with different valence states.

2. The thin film according to claim 1, characterized in that, The first metal in the first metal oxide is selected from one or more of the elements in Group VIB; the second metal in the second metal oxide is selected from one or more of the elements in Group VIB; and / or, The valence state of the first metal is 4-6, and the valence state of the second metal is 4-6; and / or, The absolute value of the conduction band energy level of the first metal oxide is greater than or equal to 4 eV, and the absolute value of the conduction band energy level of the second metal oxide is greater than or equal to 4 eV; and / or, The conductivity of the first metal oxide is greater than or equal to 100 S / cm, and the conductivity of the second metal oxide is greater than or equal to 100 S / cm.

3. The thin film according to claim 1, wherein The valence state of the first metal is higher than that of the second metal. In the thin film, the molar proportion of the first metal oxide is 0%-30%, and the molar proportion of the second metal oxide is 70%-100%.

4. The thin film according to claim 2 or 3, characterized in that, The first metal oxide is selected from one or more of MoO3 or WO3; the second metal oxide is selected from one or more of MoO2 or WO2.

5. The thin film according to claim 1, characterized in that, The thin film includes a first sub-layer and a second sub-layer. The material of the first sub-layer includes the first metal oxide and the second metal oxide, and the material of the second sub-layer includes a second material, where the refractive index of the second material is greater than or equal to 1.

2.

6. The thin film according to claim 5, wherein, The second material is selected from one or more of AlQ3, NPB, TPD, TAPC, BDAVBi, 2-TNATA, TPT1, TPBi, Bpy-OXD, DBFTrz.

7. The thin film according to claim 5, wherein The refractive index of the first sub-layer in the wavelength range of 400 nm to 700 nm is greater than or equal to 1.8; and / or, The extinction coefficient of the first sub-layer in the wavelength range of 400 nm to 700 nm is less than or equal to 0.

05.

8. A method for preparing a thin film, characterized in that, It includes the following steps: Provide a first metal oxide and a second metal oxide, deposit the first metal oxide and the second metal oxide to obtain a thin film; Wherein, the first metal in the first metal oxide and the second metal in the second metal oxide are the same metal with different valence states.

9. The method for preparing the thin film according to claim 8, characterized in that, The step of depositing the first metal oxide and the second metal oxide includes: Deposit the first metal oxide and the second metal oxide under a preset pressure to form the thin film.

10. The method for preparing a thin film according to claim 9, wherein, The preset pressure is 1×10 -4 Pa to 5×10 -4 Pa; and / or, The step of depositing the first metal oxide and the second metal oxide is specifically: deposit the first metal oxide and the second metal oxide simultaneously with a set co-evaporation rate ratio; The set co-evaporation rate ratio is (0-1):(2-10).

11. The method for preparing the thin film according to claim 8, wherein The thin film includes a first sub-layer and a second sub-layer, and the preparation method includes the following steps: Deposit the first metal oxide and the second metal oxide to form the first sub-layer; Deposit a second material on the first sub-layer to form the second sub-layer to obtain the thin film; Among them, the refractive index of the second material is greater than or equal to 1.

2.

12. An optoelectronic device, characterized in that, Comprising an anode, a functional layer, and a cathode which are stacked, the optoelectronic device further comprises a light extraction layer disposed outside at least one of the anode and the cathode, and the light extraction layer comprises the thin film according to any one of claims 1 to 7.

13. The optoelectronic device according to claim 12, characterized in that, The transmittance of the anode or the cathode in the wavelength band of 400 nm to 700 nm is not less than 20%; and / or, The materials of the anode and / or the cathode are independently selected from one or more of metals, carbon materials, and metal oxides. The metals include one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg; the carbon materials include one or more of graphite, carbon nanotubes, graphene, and carbon fibers; the metal oxides include doped or undoped metal oxides, including one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, and AMO, or a composite electrode including a metal sandwiched between doped or undoped transparent metal oxides, and the composite electrode includes one or more of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO2 / Ag / TiO2, and TiO2 / Al / TiO2; and / or, The functional layer comprises a hole functional layer, the hole functional layer comprises a hole transport layer and / or a hole injection layer, and the materials of the hole transport layer and / or the hole injection layer include at least one of TFB, CuPc, PVK, Poly-TPD, PFB, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, polyaniline, transition metal oxides, transition metal sulfides, transition metal stannides, doped graphene, undoped graphene, and C60; and / or, The functional layer further includes a light-emitting layer, and the light-emitting layer is a quantum dot light-emitting layer or an organic light-emitting layer; wherein, the material of the quantum dot light-emitting layer includes at least one of single-structure quantum dots and core-shell structure quantum dots, the material of the single-structure quantum dots, the core material of the core-shell structure quantum dots, and the shell material of the core-shell structure quantum dots are respectively selected from at least one of II-VI group compounds, IV-VI group compounds, III-V group compounds, and I-III-VI group compounds, and the shell layer of the core-shell structure quantum dots includes one or more layers; wherein, the II-VI group compounds include, but are not limited to, one or more of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe, the IV-VI group compounds include, but are not limited to, one or more of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe, the III-V group compounds include, but are not limited to, one or more of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb, and the I-III-VI group compounds include, but are not limited to, at least one of CuInS2, CuInSe2, and AgInS2;The materials of the organic light-emitting layer include at least one of 4,4'-bis(N-carbazolyl)-1,1'-biphenyl: tris[2-(p-tolyl)pyridine-C2,N]iridium(III), 4,4',4''-tris(carbazol-9-yl)triphenylamine: tris[2-(p-tolyl)pyridine-C2,N]iridium, diarylanthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPX fluorescent materials, TBRb fluorescent materials, and DBP fluorescent materials, polyacetylene and its derivatives, poly(p-phenylene) and its derivatives, polythiophene and its derivatives, polyfluorene and its derivatives; and / or; The functional layer further includes an electronic functional layer, and the electronic functional layer includes an electron transport layer and / or an electron injection layer, and the electron transport layer and / or the electron injection layer includes an inorganic material or an organic material; wherein, the inorganic material is selected from one or more of doped or undoped zinc oxide, barium oxide, aluminum oxide, nickel oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanate, aluminum zinc oxide, manganese zinc oxide, tin zinc oxide, lithium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc stannide, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, barium titanate, and the doping elements include one or more of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, gadolinium; the organic material is selected from one or more of quinoxaline compounds, imidazole compounds, triazine compounds, fluorene-containing compounds, hydroxyquinoline compounds, phosphine oxide compounds.

14. A display device, characterized in that, The display device includes the optoelectronic device according to claim 12 or 13.

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