Thin film, preparation method thereof and laminated device

Abstract

The invention belongs to the technical field of display, and particularly relates to a thin film, a preparation method thereof and a laminated device, and the thin film is used as a charge generation layer. According to the thin film provided by the invention, the number of generated photons can be multiplied under the same current density, and the efficiency and the service life of a laminated device are effectively improved.

Description

Technical Field

[0001] The present application relates to the field of display and lighting technologies, and more particularly, to a thin film, a preparation method thereof, and a stacked device. Background Art

[0002] With the development of the times, OLED display panels with fast response speed, high contrast, and low power consumption are continuously occupying the small and medium-sized display market and replacing the original LCD display products. At present, commercial OLED products are mainly realized by evaporation deposition. Limited by evaporation deposition machines, fine masks, etc., large-size OLED display panels generally have low yield and high cost. Compared with the evaporation deposition method, the solution method does not require expensive vacuum equipment and is more promising to accelerate the realization of large-size OLED display panels entering thousands of households. Therefore, the solution method technical route represented by inkjet printing has received extensive attention.

[0003] However, compared with OLEDs prepared by the evaporation deposition method, there is still a large gap in the performance of OLEDs prepared by the solution method. During the preparation by the solution method, since the solution used is acidic or alkaline and the thin film of the functional layer has weak anti-rinse and damage ability, chemical etching is likely to occur, thereby affecting the efficiency and lifespan of the light-emitting device. Summary of the Invention

[0004] The technical problem to be solved by the present application is that the efficiency and lifespan of the light-emitting device prepared by the solution method are relatively low.

[0005] To solve the above technical problem, the present application provides a thin film, and adopts the following technical solution:

[0006] A thin film, which includes a first sub-layer, a buffer layer, and a second sub-layer that are sequentially stacked. Among them, the material of the buffer layer is an insulating material.

[0007] Further, the insulating material includes a polymer material, and the conductivity of the insulating material is less than or equal to 1×10 -7 S / m;

[0008] Optionally, the polymer material includes one or more of polyethyleneimine, polyethoxyethyleneimine, polymethyl methacrylate, polyethylene terephthalate, polyvinylpyrrolidone, and polyethylene oxide;

[0009] And / or, the first sub-layer is an N-type semiconductor material;

[0010] Optionally, the N-type semiconductor material includes one or more of metal oxides, doped metal oxides, II-VI group semiconductor materials, III-V group semiconductor materials, and I-III-VI group semiconductor materials;

[0011] Among them, the metal oxide is selected from at least one of ZnO, BaO, TiO2, and SnO2; the metal oxide in the doped metal oxide is selected from at least one of ZnO, TiO2, and SnO2, and the doping element is selected from at least one of Al, Mg, Li, In, and Ga; the II-VI group semiconductor material is selected from at least one of ZnS, ZnSe, and CdS; the III-V group semiconductor material is selected from at least one of InP and GaP; the I-III-VI group semiconductor material is selected from at least one of CuInS and CuGaS;

[0012] and / or, the second sub-layer is a P-type semiconductor material;

[0013] Optionally, the P-type semiconductor material includes one or more of 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene, PEDOT, PEDOT:PSS, derivatives of PEDOT:PSS doped with s-MoO3, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, tetracyanoquinodimethane, copper phthalocyanine, nickel oxide, molybdenum oxide, tungsten oxide, vanadium oxide, molybdenum sulfide, tungsten sulfide, and copper oxide.

[0014] Furthermore, the total thickness range of the thin film is 30-70 nm;

[0015] and / or, the thickness range of the first sub-layer is 10-30 nm;

[0016] and / or, the thickness range of the buffer layer is 5-10 nm;

[0017] and / or, the thickness range of the second sub-layer is 15-30 nm.

[0018] To solve the above technical problems, the present application provides a method for preparing a thin film, adopting the following technical solutions:

[0019] A method for preparing a thin film, the steps of the preparation method include:

[0020] Providing a first solution containing a first precursor material, a second solution containing an insulating material, and a third solution containing a second precursor material;

[0021] Setting the first solution as the first sub-layer;

[0022] Depositing the second solution on the first sub-layer to form a buffer layer;

[0023] Depositing the third solution on the buffer layer to form a second sub-layer, obtaining the thin film.

[0024] Further, the first precursor material includes an n-type semiconductor precursor material;

[0025] Optionally, the n-type semiconductor precursor material includes a metal acetylacetonate;

[0026] More optionally, the metal acetylacetonate includes at least one of zinc acetylacetonate and titanium acetylacetonate;

[0027] And / or, the insulating material includes a polymer material;

[0028] Optionally, the polymer material includes one or more of polyethyleneimine, polyethoxyethyleneimine, polymethyl methacrylate, polyethylene terephthalate, polyvinylpyrrolidone, and polyethylene oxide;

[0029] And / or, the second precursor material includes a p-type semiconductor precursor material;

[0030] Optionally, the p-type semiconductor precursor material includes one or more of ammonium phosphomolybdate, ammonium molybdate, ammonium metatungstate, hexacarbonylmolybdenum, and tungsten ethoxide.

[0031] Further, the concentration range of the first solution is 5-25 mg / ml, and the solvent of the first solution includes at least one of methanol, ethanol, butanol, and acetonitrile;

[0032] And / or, the concentration range of the second solution is 3-10 mg / ml, and the solvent of the second solution includes at least one of methanol, ethanol, butanol, and acetonitrile;

[0033] And / or, the concentration range of the third solution is 5-15 mg / ml, and the solvent of the third solution includes at least one of methanol, ethanol, butanol, and acetonitrile.

[0034] Further, the specific steps of setting the first solution as the first sub-layer include:

[0035] Setting the first solution as a liquid film, and then heating and drying to form the first sub-layer; optionally, in the specific steps of setting the first solution as the first sub-layer, the heating temperature is 100-150 °C and the heating time is 5-10 min;

[0036] And / or, the specific steps of depositing the second solution on the first sub-layer to form a buffer layer include:

[0037] Deposit the second solution on the first sub-layer, and then heat and dry it to form the buffer layer; optionally, in the specific step of depositing the second solution on the first sub-layer to form the buffer layer, the heating temperature is 100-150°C and the heating time is 10-30 min;

[0038] And / or, the specific step of depositing the third solution on the buffer layer to form the second sub-layer includes:

[0039] Deposit the third solution on the buffer layer, and then heat and dry it to form the second sub-layer; optionally, in the specific step of depositing the third solution on the buffer layer to form the second sub-layer, the heating temperature is 100-150°C and the heating time is 10-30 min.

[0040] Furthermore, the total thickness range of the thin film is 30-70 nm;

[0041] And / or, the thickness range of the first sub-layer is 10-30 nm;

[0042] And / or, the thickness range of the buffer layer is 5-10 nm;

[0043] And / or, the thickness range of the second sub-layer is 15-30 nm.

[0044] To solve the above technical problems, the present application also provides a stacked device, adopting the following technical solutions:

[0045] A stacked device, the stacked device includes a charge generation layer, the charge generation layer includes the thin film as described above, or the charge generation layer is prepared by the preparation method of the thin film as described above.

[0046] Compared with the prior art, the present application mainly has the following beneficial effects:

[0047] The thin film provided by the present application, as the charge generation layer of the stacked device, can multiply the number of generated photons under the same current density, effectively improving the efficiency and lifespan of the stacked device. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the solutions in the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0049] Figure 1 It is a schematic structural diagram of the thin film of the embodiment of the present application;

[0050] Figure 2 It is a schematic structural diagram of the stacked device according to an embodiment of the present application;

[0051] Figure 3 It is a flowchart of the method for preparing the thin film according to an embodiment of the present application.

[0052] Reference numerals:

[0053] 1, first sub-layer; 2, second sub-layer; 3, buffer layer; 4, first functional unit; 41, first hole injection layer; 42, first hole transport layer; 43, first light-emitting layer; 44, first electron transport layer; 5, functional layer; 6, second functional unit; 61, second hole injection layer; 62, second hole transport layer; 63, second light-emitting layer; 64, second electron transport layer; 7, anode; 8, cathode. Detailed implementation manners

[0054] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below, and preferred embodiments of the present invention are given. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0055] It should be noted that when an element is referred to as being "provided on" another element, it can be directly provided on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time.

[0056] 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. The term "and / or" in the specification and claims of this application and the above drawings includes any and all combinations of one or more of the related listed items.

[0057] References herein to "embodiments" mean that the particular features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present 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.

[0058] Embodiment 1 of the thin film of the present application

[0059] Please refer to Figure 1 As shown, the embodiment of the present application provides a thin film, which includes a first sub-layer 1, a buffer layer 3, and a second sub-layer 2 stacked in sequence, wherein the material of the buffer layer 3 is an insulating material.

[0060] In some embodiments, the insulating material includes a polymer material, and the conductivity of the insulating material is less than or equal to 1×10 -7 S / m. In some embodiments, the conductivity of the insulating material is 1×10 -8 S / m, 1×10 -9 S / m, 1×10 - 10 S / m, 1×10 -12 S / m, 1×10 -15 S / m, 1×10 -20 S / m, or any value within the range formed between any two values.

[0061] Optionally, the polymer material includes one or more of polyethyleneimine, polyethoxyethyleneimine, polymethyl methacrylate, polyethylene terephthalate, polyvinylpyrrolidone, and polyethylene oxide.

[0062] In some embodiments, the first sub-layer 1 is an N-type semiconductor material.

[0063] Optionally, the N-type semiconductor material includes one or more of metal oxides, doped metal oxides, II-VI group semiconductor materials, III-V group semiconductor materials, and I-III-VI group semiconductor materials;

[0064] Among them, the metal oxide is selected from at least one of ZnO, BaO, TiO2, and SnO2; the metal oxide in the doped metal oxide is selected from at least one of ZnO, TiO2, and SnO2, and the doping element is selected from at least one of Al, Mg, Li, In, and Ga; the II-VI group semiconductor material is selected from at least one of ZnS, ZnSe, and CdS; the III-V group semiconductor material is selected from at least one of InP and GaP; the I-III-VI group semiconductor material is selected from at least one of CuInS and CuGaS.

[0065] In some embodiments, the second sublayer 2 is a P-type semiconductor material;

[0066] Optionally, the P-type semiconductor material includes one or more of 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene, PEDOT, PEDOT:PSS, derivatives of PEDOT:PSS doped with s-MoO3, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, tetracyanoquinodimethane, copper phthalocyanine, nickel oxide, molybdenum oxide, tungsten oxide, vanadium oxide, molybdenum sulfide, tungsten sulfide, and copper oxide.

[0067] In some embodiments, the total thickness range of the thin film is 30-70 nm, for example: any value among 30 nm, 40 nm, 50 nm, 60 nm, 70 nm or the range formed between any two values.

[0068] Optionally, the thickness range of the first sublayer is 10-30 nm, for example: any value among 10 nm, 15 nm, 20 nm, 25 nm, 30 nm or the range formed between any two values;

[0069] Optionally, the thickness range of the buffer layer is 5-10 nm, for example: any value among 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm or the range formed between any two values;

[0070] Optionally, the thickness range of the second sublayer is 15-30 nm, for example: any value among 15 nm, 20 nm, 25 nm, 30 nm or the range formed between any two values.

[0071] The thin film provided by this application, as the charge generation layer of the stacked device, can multiply the number of generated photons under the same current density, effectively improving the efficiency and lifespan of the stacked device.

[0072] Please refer to Figure 2As shown, in some embodiments, the thin film is provided as a charge generation layer in a stacked device, and the stacked device includes: an anode 7, a cathode 8, and a first functional unit 4 and a second functional unit 6 disposed between the anode 7 and the cathode 8. A functional layer 5 is provided between the first functional unit 4 and the second functional unit 6.

[0073] Optionally, the first functional unit 4 includes a first hole injection layer 41, a first hole transport layer 42, a first light-emitting layer 43, and a first electron transport layer 44 stacked in sequence. The second functional unit 6 includes a second hole injection layer 61, a second hole transport layer 62, a second light-emitting layer 63, and a second electron transport layer 64 stacked in sequence. In this embodiment, the first electron transport layer 44, the functional layer 5, and the second hole injection layer 61 form the charge generation layer, where the first electron transport layer 44 corresponds to the first sub-layer 1, the second hole injection layer 61 corresponds to the second sub-layer 2, and the functional layer 5 corresponds to the buffer layer 3.

[0074] In some embodiments, the material of the first electron transport layer 44 can be selected from first precursor materials; in this embodiment, the first precursor materials include n-type semiconductor precursor materials; optionally, the n-type semiconductor precursor materials include metal acetylacetonates; more optionally, the metal acetylacetonates include at least one of zinc acetylacetonate and titanium acetylacetonate.

[0075] In some embodiments, the material of the functional layer 5 is selected from the polymer materials; in this embodiment, the polymer materials are insulating materials; optionally, the polymer materials include one or more of polyethyleneimine, polyethoxyethyleneimine, and polymethyl methacrylate.

[0076] In some embodiments, the material of the second hole injection layer 61 can be selected from the second precursor materials; in this embodiment, the second precursor materials include p-type semiconductor precursor materials; optionally, the p-type semiconductor precursor materials include one or more of ammonium phosphomolybdate, ammonium molybdate, ammonium metatungstate, hexacarbonylmolybdenum, and tungsten ethoxide.

[0077] In this embodiment, by using precursor materials as the materials of the first sub-layer 1 and the second sub-layer 2, the compactness of the thin film can be effectively increased. During the preparation of the stacked device by the solution method, the situation of poor anti-flushing damage ability caused by using nanometer particles with large pores as the material of the carrier transport layer can be avoided, and chemical etching caused by the acidity or alkalinity of the solution can be avoided, thereby improving the efficiency and lifespan of the stacked device.

[0078] In other embodiments, the materials of the first hole injection layer 41 and the second hole injection layer 61 may be selected from at least one of poly(3,4-ethylenedioxythiophene), poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS), copper phthalocyanine, titanium oxyphthalocyanine, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, 4,4',4'-tris[2-naphthylphenylamino]triphenylamine, 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanoquinodimethane, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene, transition metal oxides or transition metal chalcogenides, wherein the transition metal oxides are selected from at least one of NiOx, MoOx, WOx, CrOx or CuOx, and the transition metal chalcogenides are selected from at least one of MoSx, MoSex, WSx, WSex or CuSx.

[0079] In other embodiments, the materials of the first hole transport layer 42 and the second hole transport layer 62 include, but are not limited to, 4,4'-N,N'-dicarbazolyl-biphenyl, N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4”-diamine, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine, N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-spiro, N,N'-bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine, 4,4',4'-tris(N-carbazolyl)-triphenylamine, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], poly(4-butylphenyl-diphenylamine), polyaniline, polypyrrole, poly(p-phenylene vinylene), poly(phenylene vinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene] and poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene], copper phthalocyanine, aromatic tertiary amines, polynuclear aromatic tertiary amines, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compounds, N,N,N',N'-tetraarylbenzidine, PEDOT:PSS and its derivatives, poly(N-vinylcarbazole) and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, N,N'-bis(naphthalen-1-yl)-N,N'-diphenylbenzidine, spiro-NPB, doped graphene, undoped graphene, C60, doped or undoped NiO, doped or undoped MoO3, doped or undoped WO3, doped or undoped V2O5, doped or undoped p-type gallium nitride, doped or undoped CrO3, doped or undoped CuO, at least one of them.

[0080] In other embodiments, the materials of the first light-emitting layer 43 and the second light-emitting layer 63 are organic light-emitting materials or quantum dot light-emitting materials; the organic light-emitting materials include 4,4'-bis(N-carbazolyl)-1,1'-biphenyl: tris[2-(p-tolyl)pyridineiridium(III), 4,4',4”-tris(carbazol-9-yl)triphenylamine: tris[2-(p-tolyl)pyridineiridium, diarylanthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPX fluorescent materials, TBRb fluorescent materials, DBP fluorescent materials, delayed fluorescence materials, TTA materials, thermally activated delayed materials, polymers containing B-N covalent bonds, hybrid local charge transfer excited state materials, exciplex light-emitting materials, polyacetylene and its derivatives, poly(p-phenylene) and its derivatives, polythiophene and its derivatives, polyfluorene and its derivatives, or one or more of them;The quantum dot light-emitting material includes one or more of single-structure quantum dots, core-shell structure quantum dots, and perovskite semiconductor materials. 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 each independently selected from one or more of II-VI group compounds, IV-VI group compounds, III-V group compounds, and I-III-VI group compounds. The II-VI group compounds include 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 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 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 one or more of CuInS2, CuInSe2, and AgInS2. The perovskite semiconductor material includes doped or undoped inorganic perovskite semiconductors or organic-inorganic hybrid perovskite semiconductors. The structural general formula of the inorganic perovskite semiconductor is AMX3, where A is a Cs+ ion and M is a divalent metal cation, including Pb; 2+ , Sn 2+ , Cu 2+ , Ni 2+, Cd 2+ , Cr 2+ , Mn 2+ , Co 2+ , Fe 2+ , Ge 2+ , Yb 2+ , Eu 2+ One or more of the following, X is a halogen anion, including one or more of Cl-, Br-, I-; the structural general formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, where B is an organic amine cation, including CH3(CH2)n-2NH 3+ or [NH3(CH2)nNH3] 2+ , where n≥2, M is a divalent metal cation, including Pb 2+ , Sn 2+ , Cu 2+ , Ni 2+ , Cd 2+ , Cr 2+ , Mn 2+ , Co 2+ , Fe 2+ , Ge 2+ , Yb 2+ , Eu 2+ One or more of the following, X is a halogen anion, including one or more of Cl-, Br-, I-.

[0081] In other embodiments, the materials of the first electron transport layer 44 and the second electron transport layer 64 are selected from one or more of doped or undoped inorganic materials and organic materials; wherein, the undoped inorganic materials are selected from at least one of ZnO, TiO2, SnO2, Al2O3, GaO, Ga2O3, ZrO2, NiO, ZnS, ZnSe, CdS, InP, GaP, BaTiO3, Cs2CO3, Rb2CO3, RbBr, LiF, LiF / Yb, MgP, MgF2; the doped inorganic materials include the undoped inorganic materials and doping elements, and the doping elements are selected from at least one of Mg, Ca, Li, Ga, Al, Co, Mn, Zr, W, Ti, Y; the organic materials are selected from at least one of polymethyl methacrylate and polyvinyl butyral.

[0082] Example 1 of the preparation method of the thin film of the present application

[0083] Please refer to Figure 3 As shown, the present application embodiment provides a preparation method of a thin film, and the steps of the preparation method include:

[0084] S100, provide a first solution containing a first precursor material, a second solution containing an insulating material, and a third solution containing a second precursor material;

[0085] S200, set the first solution as a first sub-layer;

[0086] S300, deposit the second solution on the first sub-layer to form a buffer layer;

[0087] S400, deposit the third solution on the buffer layer to form a second sub-layer, obtaining the thin film.

[0088] In some embodiments, the first precursor material includes an n-type semiconductor precursor material; optionally, the n-type semiconductor precursor material includes an acetylacetonate metal salt; more optionally, the acetylacetonate metal salt includes at least one of zinc acetylacetonate and titanium acetylacetonate. Specifically, using the first solution containing the n-type semiconductor precursor material to prepare the first sub-layer can increase the compactness of the first sub-layer without affecting the electron transport ability of the first sub-layer and improve the ability to resist damage by chemical solution rinsing.

[0089] In some embodiments, the insulating material includes a polymer material; optionally, the polymer material includes one or more of polyethyleneimine, polyethoxyethyleneimine, polymethyl methacrylate, polyethylene terephthalate, polyvinylpyrrolidone, and polyethylene oxide. Specifically, using the polymer material to prepare the buffer layer can make the thin film have a good surface morphology, ensure the light transmittance of the thin film, and improve the ability to resist damage by chemical solution rinsing.

[0090] In some embodiments, the second precursor material includes a p-type semiconductor precursor material; optionally, the p-type semiconductor precursor material includes one or more of ammonium phosphomolybdate, ammonium molybdate, ammonium metatungstate, hexacarbonylmolybdenum, and tungsten ethoxide. Specifically, using the second solution containing the p-type semiconductor precursor material to prepare the second sub-layer can increase the compactness of the second sub-layer without affecting the hole injection ability of the second sub-layer and improve the ability to resist damage by chemical solution rinsing.

[0091] It should be noted that the acetylacetonate metal salt is also called metal acetylacetonate complex, abbreviated as M(AA), including varieties such as aluminum, cobalt, nickel, copper, zinc, iron, vanadyl, chromium, titanium, manganese, potassium, and zirconium, and is commonly used as a catalyst; the metal oxide precursor can be used to prepare nanoporous metal oxides; both belong to the precursor materials that can be decomposed by heating.

[0092] In some embodiments, the concentration range of the first solution is 5-25 mg / ml, for example, any value among 5 mg / ml, 10 mg / ml, 15 mg / ml, 20 mg / ml, 25 mg / ml or the range formed between any two values; the solvent of the first solution includes at least one of methanol, ethanol, butanol and acetonitrile;

[0093] In some embodiments, the concentration range of the second solution is 3-10 mg / ml, for example, any value among 3 mg / ml, 4 mg / ml, 5 mg / ml, 6 mg / ml, 7 mg / ml, 8 mg / ml, 9 mg / ml, 10 mg / ml or the range formed between any two values; the solvent of the second solution includes at least one of methanol, ethanol, butanol and acetonitrile;

[0094] In some embodiments, the concentration range of the third solution is 5-15 mg / ml, for example, any value among 5 mg / ml, 6 mg / ml, 7 mg / ml, 8 mg / ml, 9 mg / ml, 10 mg / ml, 11 mg / ml, 12 mg / ml, 13 mg / ml, 14 mg / ml, 15 mg / ml or the range formed between any two values; the solvent of the third solution includes at least one of methanol, ethanol, butanol and acetonitrile.

[0095] In some embodiments, the specific steps of setting the first solution as the first sub-layer include:

[0096] S201, setting the first solution as a liquid film, and then heating and drying to form the first sub-layer.

[0097] Optionally, in the specific steps of setting the first solution as the first sub-layer, the heating temperature is 100-150 °C, for example, any value among 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C or the range formed between any two values; the heating time is 5-10 min, for example, any value among 5 min, 6 min, 7 min, 8 min, 9 min, 10 min or the range formed between any two values.

[0098] In some embodiments, the specific steps of depositing the second solution on the first sub-layer to form a buffer layer include:

[0099] S301, depositing the second solution on the first sub-layer, and then heating and drying to form the buffer layer.

[0100] Optionally, in the specific step of depositing the second solution on the first sub-layer to form a buffer layer, the heating temperature is 100 - 150 °C, for example, any value among 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C or a range formed between any two values; the heating time is 10 - 30 min, for example, any value among 10 min, 20 min, 30 min or a range formed between any two values.

[0101] In some embodiments, the specific step of depositing the third solution on the buffer layer to form a second sub-layer includes:

[0102] S401, deposit the third solution on the buffer layer, and then heat and dry to form the second sub-layer.

[0103] Optionally, in the specific step of depositing the third solution on the buffer layer to form a second sub-layer, the heating temperature is 100 - 150 °C, for example, any value among 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C or a range formed between any two values; the heating time is 10 - 30 min, for example, any value among 10 min, 20 min, 30 min or a range formed between any two values.

[0104] In some embodiments, the total thickness range of the thin film is 30 - 70 nm, for example, any value among 30 nm, 40 nm, 50 nm, 60 nm, 70 nm or a range formed between any two values.

[0105] Optionally, the thickness range of the first sub-layer is 10 - 30 nm, for example, any value among 10 nm, 15 nm, 20 nm, 25 nm, 30 nm or a range formed between any two values;

[0106] Optionally, the thickness range of the buffer layer is 5 - 10 nm, for example, any value among 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm or a range formed between any two values;

[0107] Optionally, the thickness range of the second sub-layer is 15 - 30 nm, for example, any value among 15 nm, 20 nm, 25 nm, 30 nm or a range formed between any two values.

[0108] The preparation method of the thin film provided by the embodiment of the present application prepares the thin film by a solution method, and the materials of the first sub-layer and the second sub-layer of the thin film are both precursor materials, and the material of the buffer layer is a polymer material, so that the thin film can be used as the charge generation layer of the stacked device. Under the same current density, the number of generated photons can be doubled, and at the same time, the anti-rinse damage ability is improved during the preparation of the stacked device by the solution method, effectively improving the efficiency and lifespan of the stacked device.

[0109] Embodiment 1 of the stacked device of the present application

[0110] The embodiment of the present application provides a stacked device, including a charge generation layer, where the charge generation layer includes the thin film as described above, or the charge generation layer is prepared by the preparation method of the thin film as described above.

[0111] Please refer to Figure 2 As shown, in some embodiments, the stacked device includes: an anode 7, a cathode 8, and a first functional unit 4 and a second functional unit 6 disposed between the anode 7 and the cathode 8. Among them, a functional layer 5 is disposed between the first functional unit 4 and the second functional unit 6.

[0112] Optionally, the first functional unit 4 includes a first hole injection layer 41, a first hole transport layer 42, a first light-emitting layer 43, and a first electron transport layer 44 stacked in sequence, and the second functional unit 6 includes a second hole injection layer 61, a second hole transport layer 62, a second light-emitting layer 63, and a second electron transport layer 64 stacked in sequence.

[0113] Preferably, the thin film is composed of the first electron transport layer 44, the functional layer 5, and the second hole injection layer 61, and serves as the charge generation layer of the stacked device. Among them, the first electron transport layer 44 is the first sub-layer of the thin film, the second hole injection layer 61 is the second sub-layer of the thin film, the functional layer 5 is the buffer layer of the thin film, the first sub-layer is disposed on the side close to the first light-emitting layer, and the second sub-layer is disposed on the side close to the second hole transport layer.

[0114] In other embodiments, the stacked device may further include several functional units such as a third functional unit and a fourth functional unit. Among them, the above-mentioned thin film is disposed between adjacent functional units as the charge generation layer between each functional unit.

[0115] In some embodiments, the material of the first electron transport layer 44 may be selected from first precursor materials; in this embodiment, the first precursor materials include n-type semiconductor precursor materials; optionally, the n-type semiconductor precursor materials include metal acetylacetonates; more optionally, the metal acetylacetonates include at least one of zinc acetylacetonate and titanium acetylacetonate.

[0116] In some embodiments, the material of the functional layer 5 is selected from the polymer materials; in this embodiment, the polymer materials are insulating materials; optionally, the polymer materials include one or more of polyethyleneimine, polyethoxyethyleneimine, and polymethyl methacrylate.

[0117] In some embodiments, the material of the second hole injection layer 61 may be selected from the second precursor materials; in this embodiment, the second precursor materials include p-type semiconductor precursor materials; optionally, the p-type semiconductor precursor materials include one or more of ammonium phosphomolybdate, ammonium molybdate, ammonium metatungstate, hexacarbonylmolybdenum, and tungsten ethoxide.

[0118] In some embodiments, the anode 7 and the cathode 8 each independently include one or several of metals, carbon materials, and metal oxides; the metals include one or several of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg; the carbon materials include one or several of graphite, carbon nanotubes, graphene, and carbon fibers; the metal oxides include metal oxide electrodes or composite electrodes with a metal disposed between doped or undoped transparent metal oxides, the materials of the metal oxide electrodes include one or several of ITO, FTO, ATO, AZO, GZO, IZO, MZO, MoO3, and AMO, and the composite electrodes include one or several 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;

[0119] In some embodiments, the materials of the first hole injection layer 41, the first hole transport layer 42, and the second hole transport layer 62 each independently include 4,4'-N,N'-dicarbazolyl-biphenyl, N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4”-diamine, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine, N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-spiro, N,N'-bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine, 4,4',4'-tris(N-carbazolyl)-triphenylamine, 4,4',4'-tris(carbazol-9-yl)triphenylamine, trichloroisocyanuric acid, terbium-doped phosphate-based green luminescent material, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], poly(4-butylphenyl-diphenylamine), poly[bis(4-phenyl)(4-butylphenyl)amine], polyaniline, polypyrrole, poly(p-phenylene vinylene), poly(phenylene vinylene), poly[2-methoxy-5-(2-ethylhexoxy)-1,4-phenylene vinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene], copper phthalocyanine, aromatic tertiary amine, polynuclear aromatic tertiary amine, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compound, N,N,N',N'-tetraarylbenzidine, PEDOT, PEDOT:PSS and its derivatives, PEDOT:PSS derivatives doped with s-MoO3, poly(N-vinylcarbazole) and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, N,N'-bis(naphthalen-1-yl)-N,One or more of N'-diphenylbenzidine, spiro-NPB, nanocrystalline diamond, microcrystalline cellulose, tetracyanoquinodimethane, doped graphene, undoped graphene, second doped metal oxide particles, second undoped metal oxide particles, metal sulfides, metal selenides, and metal nitrides, wherein the metal oxides in the second doped metal oxide particles and the metal oxides in the second undoped metal oxide particles independently include one or more of MoO3, WO3, NiO, CrO3, CuO, Cu2O, V2O5, the doping elements in the second doped metal oxide particles include one or more of Mo, W, Ni, Cr, Cu, V, the metal sulfides include one or more of CuS, MoS3, WS3, the metal selenides include one or more of MoSe3, WSe3, and the metal nitrides include p-type gallium nitride;

[0120] In some embodiments, the material of the second electron transport layer 64 includes one or more of first doped metal oxide particles, first undoped metal oxide particles, IIB-VIA group semiconductor materials, IIIA-VA group semiconductor materials, and IB-IIIA-VIA group semiconductor materials. The material of the first undoped metal oxide particles includes one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5. The metal oxides in the first doped metal oxide particles include one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, Al2O3. The doping elements in the first doped metal oxide particles include one or more of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, Ga. The IIB-VIA group semiconductor materials include one or more of ZnS, ZnSe, CdS. The IIIA-VA group semiconductor materials include one or more of InP, GaP. The IB-IIIA-VIA group semiconductor materials include one or more of CuInS, CuGaS.

[0121] The tandem device provided by the embodiment of the present application can connect two or more light-emitting units in series in the vertical direction of the substrate through its tandem structure, and can achieve the effect of doubling the efficiency and brightness under the same current. The charge generation layer of the tandem device is composed of the first electron transport layer 44, the functional layer 5, and the second hole injection layer 61, which can generate the effect of charge separation, providing holes to the first functional unit 4 and electrons to the second functional unit 6 respectively; wherein, the functional layer 5 is made of a polymer material, which can ensure the light transmittance of the tandem device and does not affect the conductivity, while the first electron transport layer 44 and the second hole injection layer 61 are made of precursor materials, which can improve the film denseness of the charge generation layer and enhance its ability to resist chemical solution washing and damage during the preparation of the tandem device by solution method, effectively improving the efficiency and lifespan of the tandem device.

[0122] It can be understood that, compared with the tandem device provided by the embodiment of the present application, the commonly used ET material for the charge generation layer in the prior art is N-type doped ZnO. Due to its colloidal nanoparticle properties, its storage conditions are harsh and the shelf life is short, the film denseness is poor, and the film's ability to resist washing and damage during solution method preparation is poor.

[0123] In other embodiments, a method for preparing a tandem device is provided, which is used to prepare the tandem device as described above, and includes the following steps:

[0124] Provide a patterned ITO substrate, and place the ITO substrate in acetone, cleaning solution, deionized water, and isopropanol in sequence for ultrasonic cleaning, and each ultrasonic cleaning needs to last for 15 minutes;

[0125] Place the ITO substrate after ultrasonic cleaning in a clean oven for drying;

[0126] Treat the surface of the dried ITO substrate by ultraviolet-ozone treatment for 5 minutes to further remove the organic substances attached to the surface of the ITO substrate and improve the work function of the ITO substrate, forming the anode 7;

[0127] Deposit the first hole injection layer 41 on the ITO substrate processed in the previous step, with a thickness of 20 - 50 nm, and place the ITO substrate on a heating table at 200 - 230 °C for 15 - 40 minutes to remove the solvent and crosslink;

[0128] Deposit the first hole transport layer 42 on the first hole injection layer 41 processed in the previous step, with a thickness of 20 - 50 nm, and place the ITO substrate on a heating table at 200 - 230 °C for 15 - 40 minutes to remove the solvent and crosslink;

[0129] Deposit the first light-emitting layer 43 on the first hole-transporting layer 42 that has undergone the above treatment, with a thickness of 60 - 90 nm, and place the ITO substrate on a heating table at 170 - 180 °C to heat for 10 min to remove the solvent;

[0130] Deposit the first electron-transporting layer 44 on the first light-emitting layer 43 that has undergone the above treatment, with a thickness of 10 - 30 nm, and place the ITO substrate on a heating table at 100 - 150 °C to heat for 5 - 10 min to remove the solvent and decompose;

[0131] Deposit the functional layer 5 on the first electron-transporting layer 44 that has undergone the above treatment, with a thickness of 5 - 10 nm, and place the ITO substrate on a heating table at 100 - 150 °C to heat for 10 - 30 min to remove the solvent;

[0132] Deposit the second hole-injecting layer 61 on the functional layer 5 that has undergone the above treatment, with a thickness of 15 - 30 nm, and place the ITO substrate on a heating table at 100 - 150 °C to heat for 10 - 30 min to remove the solvent and decompose;

[0133] Deposit the second hole-transporting layer 62 on the second hole-injecting layer 61 that has undergone the above treatment, with a thickness of 20 - 50 nm, and place the ITO substrate on a heating table at 200 - 230 °C to heat for 15 - 40 min to remove the solvent and crosslink;

[0134] Deposit the second light-emitting layer 63 on the second hole-transporting layer 62 that has undergone the above treatment, with a thickness of 60 - 90 nm, and place the ITO substrate on a heating table at 170 - 180 °C to heat for 10 min to remove the solvent;

[0135] Place the deposited ITO substrate in an evaporation chamber, thermally evaporate the second electron-transporting layer 64 with a thickness of 20 - 30 nm and Al with a thickness of 100 nm as the cathode through a mask plate, and perform encapsulation and testing to form the stacked device.

[0136] The above scheme is further described below in conjunction with specific embodiments. The embodiments of the present invention are described in detail as follows:

[0137] Film Example 1

[0138] Specific preparation steps of the film provided in the embodiment of the present application:

[0139] (1) Provide a substrate;

[0140] (2) In a glove box, take zinc acetylacetonate and place it in an ethanol solvent, stir and dissolve it at a temperature of 70 °C for 24 h, and filter it with a 0.22 μm filter head to obtain a first solution with a concentration of 25 mg / ml;

[0141] (3) Spin-coat the first solution on the substrate at a rotational speed of 3000 rpm for 60 s; after spin-coating, place it on a heating table at 150 °C in a nitrogen environment and heat for 10 min to form a first sub-layer with a thickness of 30 nm.

[0142] (4) In a glove box, take polyethyleneimine and place it in an ethanol solvent, stir and dissolve it at room temperature for 24 h, and filter it with a 0.22 μm filter head to obtain a second solution with a concentration of 10 mg / ml.

[0143] (5) Spin-coat the second solution on the first sub-layer at a rotational speed of 4000 rpm for 60 s; after spin-coating, place it on a heating table at 150 °C in a nitrogen environment and heat for 30 min to form a buffer layer with a thickness of 10 nm.

[0144] (6) In a glove box, take ammonium phosphomolybdate and place it in an ethanol solvent, stir and dissolve it at room temperature for 24 h, and filter it with a 0.22 μm filter head to obtain a third solution with a concentration of 15 mg / ml.

[0145] (7) Spin-coat the third solution on the buffer layer at a rotational speed of 4000 rpm for 60 s; after spin-coating, place it on a heating table at 150 °C in a nitrogen environment and heat for 30 min to form a second sub-layer with a thickness of 30 nm.

[0146] Film Example 2

[0147] The difference between this example and Example 1 is only that:

[0148] In step (2), zinc acetylacetonate is replaced by titanium acetylacetonate.

[0149] Film Example 3

[0150] The difference between this example and Example 1 is only that:

[0151] In step (6), ammonium phosphomolybdate is replaced by tungsten ethanolate.

[0152] Film Example 4

[0153] The difference between this example and Example 1 is only that:

[0154] In step (4), polyethyleneimine is replaced by polyethoxyethyleneimine.

[0155] Film Example 5

[0156] The difference between this example and Example 1 is only that:

[0157] In step (4), polyethyleneimine is replaced by polymethyl methacrylate.

[0158] Thin film Comparative Example 1

[0159] The difference between Comparative Example 1 and Example 1 is only that:

[0160] Steps (2)-(7) are changed to: Take nano-ZnO and place it in an ethanol solvent, stir and dissolve it at room temperature for 24 h, and filter it with a 0.22-μm filter head to obtain a ZnO solution with a concentration of 10 mg / ml. At a rotation speed of 6000 rpm, spin-coat the ZnO solution on the substrate for 120 s; after spin-coating, place it on a heating table at 200 °C in a nitrogen environment and heat it for 60 min to form a thin film with a thickness of 70 nm.

[0161] Thin film Comparative Example 2

[0162] The difference between Comparative Example 2 and Example 1 is only that:

[0163] In step (4), polyethyleneimine is replaced by nano-ZnO.

[0164] Thin film Comparative Example 3

[0165] The difference between Comparative Example 3 and Example 1 is only that:

[0166] In step (2), zinc acetylacetonate is replaced by nano-ZnO.

[0167] Stacked device Example 1

[0168] The specific preparation steps of the stacked devices corresponding to the three colors of R / G / B respectively provided in the embodiments of the present application:

[0169] Specific preparation steps of the stacked device corresponding to the R (Red) color:

[0170] (1) Provide a patterned ITO substrate, and place the ITO substrate in acetone, cleaning solution, deionized water, and isopropanol in sequence for ultrasonic cleaning, and each ultrasonic cleaning needs to last for 15 min;

[0171] (2) Place the ITO substrate after ultrasonic cleaning in a clean oven and dry it;

[0172] (3) Treat the surface of the dried ITO substrate by ultraviolet-ozone treatment for 5 min to further remove the organic matter attached to the surface of the ITO substrate and improve the work function of the ITO substrate to form an anode;

[0173] (4) Deposit PEDOT:PSS on the ITO substrate treated in the previous step, with a thickness of 35 nm, and place the ITO substrate on a heating table at 220 °C and heat it for 30 min to remove the solvent and crosslink to form a hole injection layer;

[0174] (5) Deposit doped graphene on the hole injection layer processed in the previous step, with a thickness of 35 nm, and place the ITO substrate on a heating table at 220 °C to heat for 30 min to remove the solvent and crosslink, forming a hole transport layer;

[0175] (6) Deposit DBP fluorescent material on the hole transport layer processed in the previous step, with a thickness of 75 nm, and place the ITO substrate on a heating table at 175 °C to heat for 10 min to remove the solvent, forming a light-emitting layer;

[0176] (7) Deposit a zinc acetylacetonate solution with ethanol as the solvent and a concentration of 25 mg / ml on the light-emitting layer processed in the previous step, with a thickness of 30 nm, and place the ITO substrate on a heating table at 150 °C to heat for 10 min to remove the solvent and decompose, forming the first sub-layer of the above-mentioned thin film;

[0177] (8) Deposit a polyethyleneimine solution with ethanol as the solvent and a concentration of 10 mg / ml on the first sub-layer processed in the previous step, with a thickness of 10 nm, and place the ITO substrate on a heating table at 150 °C to heat for 30 min to remove the solvent, forming a buffer layer of the above-mentioned thin film;

[0178] (9) Deposit an ammonium phosphomolybdate solution with ethanol as the solvent and a concentration of 15 mg / ml on the buffer layer processed in the previous step, with a thickness of 30 nm, and place the ITO substrate on a heating table at 150 °C to heat for 30 min to remove the solvent and decompose, forming the second sub-layer of the above-mentioned thin film;

[0179] (10) Deposit doped graphene on the second sub-layer processed in the previous step, with a thickness of 35 nm, and place the ITO substrate on a heating table at 220 °C to heat for 30 min to remove the solvent and crosslink, forming a hole transport layer;

[0180] (11) Deposit DBP fluorescent material on the hole transport layer processed in the previous step, with a thickness of 75 nm, and place the ITO substrate on a heating table at 175 °C to heat for 10 min to remove the solvent, forming a light-emitting layer;

[0181] (12) Place the deposited ITO substrate in an evaporation chamber, and thermally evaporate non-doped NiO with a thickness of 25 nm as an electron transport layer and Al with a thickness of 100 nm as a cathode through a mask plate, and then perform encapsulation and testing to form a stacked device.

[0182] Specific preparation steps for the stacked device corresponding to the G (Green) color:

[0183] (1) Provide a patterned ITO substrate, and place the ITO substrate in acetone, cleaning solution, deionized water, and isopropanol in sequence for ultrasonic cleaning, and each ultrasonic cleaning needs to last for 15 min;

[0184] (2) Place the ITO substrate after ultrasonic treatment in a clean oven for drying;

[0185] (3) Treat the surface of the dried ITO substrate by ultraviolet-ozone treatment for 5 min to further remove the organic substances attached to the surface of the ITO substrate and improve the work function of the ITO substrate, forming an anode;

[0186] (4) Deposit PEDOT:PSS on the ITO substrate after the above treatment, with a thickness of 35 nm, and place the ITO substrate on a heating table at 220 °C for 30 min to remove the solvent and crosslink, forming a hole injection layer;

[0187] (5) Deposit doped graphene on the hole injection layer after the above treatment, with a thickness of 35 nm, and place the ITO substrate on a heating table at 220 °C for 30 min to remove the solvent and crosslink, forming a hole transport layer;

[0188] (6) Deposit TBRb fluorescent material on the hole transport layer after the above treatment, with a thickness of 75 nm, and place the ITO substrate on a heating table at 175 °C for 10 min to remove the solvent, forming a light-emitting layer;

[0189] (7) Deposit a zinc acetylacetonate solution with ethanol as the solvent and a concentration of 25 mg / ml on the light-emitting layer after the above treatment, with a thickness of 30 nm, and place the ITO substrate on a heating table at 150 °C for 10 min to remove the solvent and decompose, forming the first sub-layer of the above thin film;

[0190] (8) Deposit a polyethyleneimine solution with ethanol as the solvent and a concentration of 10 mg / ml on the first sub-layer after the above treatment, with a thickness of 10 nm, and place the ITO substrate on a heating table at 150 °C for 30 min to remove the solvent, forming a buffer layer of the above thin film;

[0191] (9) Deposit an ammonium phosphomolybdate solution with ethanol as the solvent and a concentration of 15 mg / ml on the buffer layer after the above treatment, with a thickness of 30 nm, and place the ITO substrate on a heating table at 150 °C for 30 min to remove the solvent and decompose, forming the second sub-layer of the above thin film;

[0192] (10) Deposit doped graphene on the second sub-layer after the above treatment, with a thickness of 35 nm, and place the ITO substrate on a heating table at 220 °C for 30 min to remove the solvent and crosslink, forming a hole transport layer;

[0193] (11) Deposit TBRb fluorescent material on the hole transport layer after the above treatment, with a thickness of 75 nm, and place the ITO substrate on a heating table at 175 °C for 10 min to remove the solvent, forming a light-emitting layer;

[0194] (12) Place the completed ITO substrate in the evaporation chamber, thermally evaporate undoped NiO with a thickness of 25 nm as the electron transport layer and Al with a thickness of 100 nm as the cathode through a mask plate, and then perform encapsulation and testing to form a stacked device.

[0195] Specific preparation steps for the stacked device corresponding to the B (Blue) color:

[0196] (1) Provide a patterned ITO substrate, and place the ITO substrate in acetone, cleaning solution, deionized water, and isopropanol in sequence for ultrasonic cleaning, and each ultrasonic cleaning needs to last for 15 min;

[0197] (2) Place the ITO substrate after ultrasonic cleaning in a clean oven to dry;

[0198] (3) Treat the surface of the dried ITO substrate by ultraviolet-ozone treatment for 5 min to further remove the organic substances attached to the surface of the ITO substrate and improve the work function of the ITO substrate to form the anode;

[0199] (4) Deposit PEDOT:PSS on the ITO substrate after the above treatment, with a thickness of 35 nm, and place the ITO substrate on a heating table at 220 °C to heat for 30 min to remove the solvent and crosslink to form the hole injection layer;

[0200] (5) Deposit doped graphene on the hole injection layer after the above treatment, with a thickness of 35 nm, and place the ITO substrate on a heating table at 220 °C to heat for 30 min to remove the solvent and crosslink to form the hole transport layer;

[0201] (6) Deposit the TBPe fluorescent material on the hole transport layer after the above treatment, with a thickness of 75 nm, and place the ITO substrate on a heating table at 175 °C to heat for 10 min to remove the solvent to form the light-emitting layer;

[0202] (7) Deposit a zinc acetylacetonate solution with ethanol as the solvent and a concentration of 25 mg / ml on the light-emitting layer after the above treatment, with a thickness of 30 nm, and place the ITO substrate on a heating table at 150 °C to heat for 10 min to remove the solvent and decompose to form the first sub-layer of the above thin film;

[0203] (8) Deposit a polyethyleneimine solution with ethanol as the solvent and a concentration of 10 mg / ml on the first sub-layer after the above treatment, with a thickness of 10 nm, and place the ITO substrate on a heating table at 150 °C to heat for 30 min to remove the solvent to form the buffer layer of the above thin film;

[0204] (9) Deposit an ammonium phosphomolybdate solution with ethanol as the solvent and a concentration of 15 mg / ml on the buffer layer processed in the previous step, with a thickness of 30 nm, and place the ITO substrate on a heating table at 150 °C for 30 min to remove the solvent and decompose it, forming the second sub-layer of the above-mentioned thin film;

[0205] (10) Deposit doped graphene on the second sub-layer processed in the previous step, with a thickness of 35 nm, and place the ITO substrate on a heating table at 220 °C for 30 min to remove the solvent and crosslink it, forming a hole transport layer;

[0206] (11) Deposit a TBPe fluorescent material on the hole transport layer processed in the previous step, with a thickness of 75 nm, and place the ITO substrate on a heating table at 175 °C for 10 min to remove the solvent, forming a light-emitting layer;

[0207] (12) Place the deposited ITO substrate in an evaporation chamber, and thermally evaporate non-doped NiO with a thickness of 25 nm as an electron transport layer and Al with a thickness of 100 nm as a cathode through a mask plate, and then perform encapsulation and testing to form a stacked device.

[0208] Examples 2 - 5 of stacked devices and Comparative Examples 1 - 3 of stacked devices

[0209] The differences between Examples 2 - 5 of stacked devices and Comparative Examples 1 - 3 of stacked devices and Example 1 of stacked devices are only that: the methods described in Examples 2 - 5 of thin films and Comparative Examples 1 - 3 of thin films are respectively used to prepare the charge generation layer.

[0210] Analysis of test results:

[0211] Through an IVL test system, under a constant current drive of 63.7 mA / cm2, the current efficiency (CE) and lifespan of the stacked device were tested, and the test results are shown in Table 1 below:

[0212]

[0213] Table 1

[0214] From the comparison of the current efficiency and lifespan of the stacked devices in Examples 1 - 5 of stacked devices and Comparative Example 1 of stacked devices, it can be known that by using a precursor material and a polymer material to form a thin film with a stacked structure as the charge generation layer of the stacked device, compared with using nano-ZnO as the material of the charge generation layer, the current efficiency and lifespan of the stacked device have been significantly improved.

[0215] From the comparison of the current efficiency and lifespan of the stacked devices in Examples 1-5 of the stacked device and Comparative Example 2 of the stacked device, it can be known that by using nano-ZnO as the material of the buffer layer, while the first sub-layer and the second sub-layer of the thin film still use the precursor material, the efficiency and lifespan of the stacked device are lower than those when using a polymer material as the material of the buffer layer.

[0216] From the comparison of the current efficiency and lifespan of the stacked devices in Examples 1-5 of the stacked device and Comparative Example 3 of the stacked device, it can be known that in the embodiments of the present application, by using a precursor material to form a carrier transport layer in the thin film provided in the stack and using the thin film as the charge generation layer of the stacked device, the efficiency and lifespan of the stacked device can be effectively improved.

[0217] In summary, the thin film provided in the present application as the charge generation layer of the stacked device can multiply the number of generated photons under the same current density, improve the efficiency of the stacked device, and a buffer layer formed of a polymer material is provided, which can increase the compactness of the thin film, improve the anti-flushing damage ability during the preparation of the stacked device by the solution method, and improve the lifespan of the stacked device.

[0218] Obviously, the embodiments described above are only a part of the embodiments of the present application, rather than all the embodiments. The drawings show the preferred embodiments of the present application, 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 directly or indirectly using the content of the specification and drawings of the present application in other related technical fields shall be within the scope of the patent protection of the present application by the same token.

Claims

1. A film, characterized in that, The thin film includes a first sub-layer, a buffer layer, and a second sub-layer that are stacked in sequence. Among them, the material of the buffer layer is an insulating material, and the conductivity of the insulating material is less than or equal to 1×10 -7 S / m.

2. The thin film according to claim 1, wherein The insulating material includes a polymer material; Optionally, the polymer material includes one or more of polyethyleneimine, polyethoxyethyleneimine, polymethyl methacrylate, polyethylene terephthalate, polyvinylpyrrolidone, and polyethylene oxide; And / or, the first sub-layer is an N-type semiconductor material; Optionally, the N-type semiconductor material includes one or more of metal oxides, doped metal oxides, II-VI group semiconductor materials, III-V group semiconductor materials, and I-III-VI group semiconductor materials; Wherein, the metal oxide is selected from at least one of ZnO, BaO, TiO2, and SnO2; the metal oxide in the doped metal oxide is selected from at least one of ZnO, TiO2, and SnO2, and the doping element is selected from at least one of Al, Mg, Li, In, and Ga; the II-VI group semiconductor material is selected from at least one of ZnS, ZnSe, and CdS; the III-V group semiconductor material is selected from at least one of InP and GaP; the I-III-VI group semiconductor material is selected from at least one of CuInS and CuGaS; And / or, the second sub-layer is a P-type semiconductor material; Optionally, the P-type semiconductor material includes one or more of 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene, PEDOT, PEDOT:PSS, derivatives of PEDOT:PSS doped with s-MoO3, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, tetracyanoquinodimethane, copper phthalocyanine, nickel oxide, molybdenum oxide, tungsten oxide, vanadium oxide, molybdenum sulfide, tungsten sulfide, and copper oxide.

3. The thin film according to claim 1, wherein The total thickness range of the thin film is 30-70 nm; And / or, the thickness range of the first sub-layer is 10-30 nm; And / or, the thickness range of the buffer layer is 5-10 nm; And / or, the thickness range of the second sub-layer is 15-30 nm.

4. A method for preparing a thin film, characterized in that, The steps of the preparation method include: Providing a first solution containing a first precursor material, a second solution containing an insulating material, and a third solution containing a second precursor material; Setting the first solution as the first sub-layer; Depositing the second solution on the first sub-layer to form a buffer layer; Depositing the third solution on the buffer layer to form a second sub-layer, obtaining the thin film.

5. The method for preparing a thin film according to claim 4, characterized in that, The first precursor material includes an n-type semiconductor precursor material; Optionally, the n-type semiconductor precursor material includes an acetylacetonate metal salt; More optionally, the acetylacetonate metal salt includes at least one of zinc acetylacetonate and titanium acetylacetonate; And / or, the insulating material includes a polymer material; Optionally, the polymer material includes one or more of polyethyleneimine, polyethoxyethyleneimine, polymethyl methacrylate, polyethylene terephthalate, polyvinylpyrrolidone, and polyethylene oxide; And / or, the second precursor material includes a p-type semiconductor precursor material; Optionally, the p-type semiconductor precursor material includes one or more of ammonium phosphomolybdate, ammonium molybdate, ammonium metatungstate, molybdenum hexacarbonyl, and tungsten ethoxide.

6. The method for preparing the thin film according to claim 4, characterized in that, The concentration range of the first solution is 5-25 mg / ml, and the solvent of the first solution includes at least one of methanol, ethanol, butanol, and acetonitrile; And / or, the concentration range of the second solution is 3-10 mg / ml, and the solvent of the second solution includes at least one of methanol, ethanol, butanol, and acetonitrile; And / or, the concentration range of the third solution is 5-15 mg / ml, and the solvent of the third solution includes at least one of methanol, ethanol, butanol, and acetonitrile.

7. The method for preparing the thin film according to claim 4, wherein The specific steps of setting the first solution as the first sub-layer include: Setting the first solution as a liquid film, and then heating and drying to form the first sub-layer; optionally, in the specific steps of setting the first solution as the first sub-layer, the heating temperature is 100-150 °C, and the heating time is 5-10 min; And / or, the specific steps of depositing the second solution on the first sub-layer to form a buffer layer include: Depositing the second solution on the first sub-layer, and then heating and drying to form the buffer layer; optionally, in the specific steps of depositing the second solution on the first sub-layer to form a buffer layer, the heating temperature is 100-150 °C, and the heating time is 10-30 min; And / or, the specific steps of depositing the third solution on the buffer layer to form a second sub-layer include: Depositing the third solution on the buffer layer, and then heating and drying to form the second sub-layer; optionally, in the specific steps of depositing the third solution on the buffer layer to form a second sub-layer, the heating temperature is 100-150 °C, and the heating time is 10-30 min.

8. The method for preparing a thin film according to claim 4, characterized in that, The total thickness range of the thin film is 30-70 nm; And / or, the thickness range of the first sub-layer is 10-30 nm; And / or, the thickness range of the buffer layer is 5-10 nm; And / or, the thickness range of the second sub-layer is 15-30 nm.

9. A stacked device, the stacked device comprising a charge generation layer, characterized in that, The charge generation layer includes the thin film according to any one of claims 1-3, or the charge generation layer is prepared by the preparation method of the thin film according to any one of claims 4-9.

10. The stacked device according to claim 9, characterized in that, The stacked device further includes an anode, a first hole injection layer, a first hole transport layer, a first light-emitting layer, a second hole transport layer, a second light-emitting layer, a second electron transport layer, and a cathode which are stacked in sequence, wherein the charge generation layer is disposed between the first light-emitting layer and the second hole transport layer, the first sub-layer in the charge generation layer is disposed on the side close to the first light-emitting layer, and the second sub-layer in the charge generation layer is disposed on the side close to the second hole transport layer; Optionally, each of the anode and the cathode independently includes one or more of a metal, a carbon material, and a metal oxide; the metal includes one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg; the carbon material includes one or more of graphite, carbon nanotubes, graphene, and carbon fiber; the metal oxide includes a metal oxide electrode or a composite electrode with a metal disposed between doped or undoped transparent metal oxides, the material of the metal oxide electrode includes one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, MoO3, and AMO, 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; Optionally, the materials of the first hole injection layer, the first hole transport layer, and the second hole transport layer each independently include 4,4'-N,N'-dicarbazolyl-biphenyl, N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4”-diamine, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine, N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-spiro, N,N'-bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine, 4,4',4'-tris(N-carbazolyl)-triphenylamine, 4,4',4'-tris(carbazol-9-yl)triphenylamine, trichloroisocyanuric acid, terbium-doped phosphate-based green light-emitting material, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], poly(4-butylphenyl-diphenylamine), poly[bis(4-phenyl)(4-butylphenyl)amine], polyaniline, polypyrrole, poly(p-phenylene vinylene), poly(phenylene vinylene), poly[2-methoxy-5-(2-ethylhexoxy)-1,4-phenylene vinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene], copper phthalocyanine, aromatic tertiary amine, polynuclear aromatic tertiary amine, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compound, N,N,N',N'-tetraarylbenzidine, PEDOT, PEDOT:PSS and its derivatives, PEDOT:PSS derivatives doped with s-MoO3, poly(N-vinylcarbazole) and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, N,N'-bis(naphthalen-1-yl)-N,One or more of N'-diphenylbenzidine, spiro-NPB, nanocrystalline diamond, microcrystalline cellulose, tetracyanoquinodimethane, doped graphene, undoped graphene, second doped metal oxide particles, second undoped metal oxide particles, metal sulfides, metal selenides, and metal nitrides, wherein the metal oxides in the second doped metal oxide particles and the metal oxides in the second undoped metal oxide particles each independently include one or more of MoO3, WO3, NiO, CrO3, CuO, Cu2O, V2O5, the doping elements in the second doped metal oxide particles include one or more of Mo, W, Ni, Cr, Cu, V, the metal sulfides include one or more of CuS, MoS3, WS3, the metal selenides include one or more of MoSe3, WSe3, and the metal nitrides include p-type gallium nitride; Optionally, the material of the second electron transport layer includes one or more of first doped metal oxide particles, first undoped metal oxide particles, IIB-VIA group semiconductor materials, IIIA-VA group semiconductor materials, and IB-IIIA-VIA group semiconductor materials. The material of the first undoped metal oxide particles includes one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5. The metal oxides in the first doped metal oxide particles include one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, and Al2O3. The doping elements in the first doped metal oxide particles include one or more of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, and Ga. The IIB-VIA group semiconductor materials include one or more of ZnS, ZnSe, and CdS. The IIIA-VA group semiconductor materials include one or more of InP and GaP. The IB-IIIA-VIA group semiconductor materials include one or more of CuInS and CuGaS.

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