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

Abstract

The invention discloses a thin film and a preparation method thereof, a photoelectric device and a display device. The preparation method of the thin film comprises the following steps: providing a thin film material solution containing a main body material; depositing the thin film material solution to obtain a liquid film; the liquid film is placed in air flow to be treated, and a thin film is obtained; wherein the main body material comprises one or more of an N-type semiconductor material, a P-type semiconductor material, an organic light-emitting material and a quantum dot light-emitting material. According to the method, the solvent in the liquid film is taken away through the flowing airflow, the film forming quality can be improved, and the cracking rate of the film is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor devices, and particularly to a thin film, a preparation method thereof, an optoelectronic device, and a display device. Background Art

[0002] Semiconductor materials are a type of electronic materials with semiconductor properties, which can be used to fabricate semiconductor devices and integrated circuits. Thin films made of semiconductor materials are widely used in the field of optoelectronic technology.

[0003] Currently, the mainstream film formation method is the solution method. By coating a solution dispersed with thin film materials on a substrate to form a liquid film, and then heating the substrate with a hot plate to remove the solvent, a thin film is formed; however, the thin film obtained by this method is prone to cracking. Summary of the Invention

[0004] In view of this, the present application provides a thin film, a preparation method thereof, an optoelectronic device, and a display device.

[0005] The embodiments of the present application are implemented as follows:

[0006] In a first aspect, an embodiment of the present application provides a preparation method of a thin film, including the following steps:

[0007] Providing a thin film material solution containing a host material;

[0008] Depositing the thin film material solution to obtain a liquid film;

[0009] Placing the liquid film in an air flow for treatment to obtain a thin film;

[0010] Wherein, the host material includes one or more of an N-type semiconductor material, a P-type semiconductor material, an organic light-emitting material, and a quantum dot light-emitting material.

[0011] In a second aspect, an embodiment of the present application provides a thin film prepared by the preparation method described above.

[0012] In a third aspect, an embodiment of the present application provides an optoelectronic device, including a stacked first electrode, one or more functional layers, and a second electrode. Among the one or more functional layers, at least one of the functional layers includes the thin film prepared by the preparation method described above or the thin film described above.

[0013] In a fourth aspect, the present application proposes a display device including the optoelectronic device described above.

[0014] The preparation method provided by the technical solution of the present application helps to improve the film formation quality and reduce the cracking rate of the thin film by removing the solvent in the liquid film with a flowing air flow. Description of the Drawings

[0015] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those skilled in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings.

[0016] Figure 1 It is a schematic structural diagram of a method for preparing a thin film provided by an embodiment of the present application;

[0017] Figure 2 It is a schematic structural diagram of an optoelectronic device provided by an embodiment of the present application;

[0018] Figure 3 It is a schematic process diagram when performing step S30 on the liquid film;

[0019] Figure 4 is Figure 3 a schematic diagram of the orientations of the second gas flow and the third gas flow in

[0020] Reference numerals: optoelectronic device 100; anode 10; cathode 20; light-emitting layer 30; hole transport layer 40, hole injection layer 50, electron transport layer 60; first gas flow 101; second gas flow 102; third gas flow 103; liquid film 104. Detailed implementation manners

[0021] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application. In addition, it should be understood that the specific implementation manners described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, unless otherwise stated, the orientation words such as "upper" and "lower" are specifically the drawing directions in the drawings. In addition, in the description of the present application, the term "including" means "including but not limited to". The various embodiments of the present application may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and simplicity, and should not be construed as a rigid limitation on the scope of the present application; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and single values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within that range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. In addition, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0022] In the present application, "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. Wherein A and B may be singular or plural.

[0023] In the present application, "at least one" means one or more, and "a plurality" means two or more. "At least one kind", "at least one of the following items (pieces)" or similar expressions refer to any combination of these items, including any combination of single items (pieces) or plural items (pieces). For example, "at least one of a, b, or c", or "at least one of a, b, and c" can both represent: a, b, c, a - b (i.e., a and b), a - c, b - c, or a - b - c, where a, b, and c can be single or multiple respectively.

[0024] In a first aspect, an embodiment of the present application provides a method for preparing a thin film, which can prepare a thin film with good film-forming effect, not easily cracked, and high yield. The thin film has good semiconductor characteristics and can be used to prepare the light-emitting layer 30, the electronic functional layer, or the hole functional layer of the optoelectronic device 100. Specifically, please refer to Figure 1 , the preparation method includes the following steps:

[0025] S10. Provide a thin film material solution containing a matrix material;

[0026] S20. Deposit the thin film material solution to obtain a liquid film 104;

[0027] S30. Place the liquid film 104 in an air stream for treatment to obtain a thin film;

[0028] Wherein, the matrix material includes one or more of an N-type semiconductor material, a P-type semiconductor material, an organic light-emitting material, and a quantum dot light-emitting material.

[0029] In the preparation method provided by the technical solution of this application, the liquid film 104 is in an air stream, and the flowing air stream can carry away the solvent in the liquid film 104, promoting the evaporation of the solvent, avoiding uneven heating caused by heating with a hot plate, helping to improve the film-forming quality, reducing the cracking rate of the thin film, and increasing the yield of the thin film.

[0030] According to the different matrix materials in the thin film, the obtained thin film has different characteristics, and thus can be applied in different directions.

[0031] When the matrix material is an N-type semiconductor material, the matrix material has electron transport or electron injection performance. Correspondingly, the obtained thin film also has electron transport or electron injection performance and can be used to prepare the electron functional layer of the optoelectronic device 100. In some embodiments, the N-type semiconductor material may include, but is not limited to, one or more of metal oxides, doped metal oxides, IIB-VIA group materials, IIIB-VA group materials, and IB-IIIB-VIA group materials; the metal oxides may include, but are not limited to, one or more of ZnO, TiO2, and SnO2; the metal oxides in the doped metal oxides may include, but are not limited to, one or more of ZnO, TiO2, and SnO2, and the doping elements may include, but are not limited to, one or more of Al, Mg, Li, In, and Ga; the IIB-VIA group materials may include, but are not limited to, one or more of ZnS, ZnSe, CdS, and CdSe; the IIIB-VA group materials may include, but are not limited to, one or more of InP and GaP; the IB-IIIB-VIA group materials may include, but are not limited to, one or more of CuInS and CuGaS.

[0032] When the host material is a p-type semiconductor material, the host material has hole transport or hole injection properties, and the p-type semiconductor material includes a first material or a second material. Correspondingly, the prepared thin film also has hole transport or hole injection properties and can be used to prepare a hole functional layer of the optoelectronic device 100. The hole functional layer includes one or both of a hole transport layer 40 and a hole injection layer 50. Specifically, when the host material is the first material, it can be used to prepare the hole transport layer 40, and when the host material is the second material, it can be used to prepare the hole injection layer 50. In some embodiments, the p-type semiconductor material includes a first material or a second material. The first material may include, but is not limited to, 4,4'-N,N'-dicarbazolyl-biphenyl (CBP), poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))] (TFB), N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4”-diamine (α-NPD), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TPD), N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-spiro(spiro-TPD), N,N'-bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine (DNTPD), tris(3-methylphenylphenylamino)-triphenylamine (m-MTDATA), poly(p-phenylene vinylene) (PPV), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene] (MEH-PPV), poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene] (MOMO-PPV), copper phthalocyanine, 4,4'-bis(para-carbazolyl)-1,1'-biphenyl compound, N,N,N',N'-tetraarylbenzidine, PEDOT:PSS, poly(N-vinylcarbazole) (PVK), polymethacrylate, poly(9,9-octylfluorene), poly(spirofluorene), N,N'-bis(naphthalen-1-yl)-N,N'-diphenylbenzidine (NPB), spiro-NPB, or one or more of them; the second material may include, but is not limited to, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene, PEDOT, PEDOT:PSS, a derivative 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, or at least one of them.

[0033] When the host material is one or more of an organic light-emitting material and a quantum dot light-emitting material, the obtained film has light-emitting properties and can be used as the light-emitting layer 30 of the optoelectronic device 100. In some embodiments, the organic light-emitting material includes one or more of 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 material, TTPX fluorescent material, TBRb fluorescent material, DBP fluorescent material, delayed fluorescence material, TTA material, thermally activated delayed material, polymer containing B-N covalent bond, hybrid local charge transfer excited state material, exciplex light-emitting material; the quantum dot light-emitting material includes at least one of a single structure quantum dot, a core-shell structure quantum dot, and a perovskite semiconductor material; the material of the single structure quantum dot, the core material of the core-shell structure quantum dot, and the shell material of the core-shell structure quantum dot respectively include at least one 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 at least one 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 at least one of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe;The group III-V compounds include at least one 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 group I-III-VI compounds include at least one of CuInS2, CuInSe2 and AgInS2. As an example, the core-shell structured quantum dots can be selected from but not limited to at least one of CdZnSe / CdZnSe / ZnSe / CdZnS / ZnS, CdZnSe / CdZnSe / CdZnS / ZnS CdSe / CdSeS / CdS, InP / ZnSeS / ZnS, CdZnSe / ZnSe / ZnS, CdSeS / ZnSeS / ZnS, CdSe / ZnS, CdSe / ZnSe / ZnS, ZnSe / ZnS, ZnSeTe / ZnS, CdSe / CdZnSeS / ZnS and InP / ZnSe / ZnS.;

[0034] It should be noted that for the materials of the aforementioned single-structured quantum dots, or the core materials of the core-shell structured quantum dots, or the shell materials of the core-shell structured quantum dots, the chemical formulas provided only indicate the elemental composition and do not indicate the content of each element. For example, CdZnSe only indicates that it is composed of three elements, Cd, Zn and Se. If the content of each element is to be indicated, it corresponds to Cd x Zn 1-x Se, 0 < x < 1.

[0035] The perovskite semiconductor materials include doped or undoped inorganic perovskite semiconductors, or organic-inorganic hybrid perovskite semiconductors; the general structural formula of the inorganic perovskite semiconductors is AMX3, where A is Cs + ion, M is a divalent metal cation selected from Pb 2+ , Sn 2+ , Cu 2+ , Ni 2+ , Cd 2+ , Cr 2+ , Mn 2+ , Co 2+ , Fe 2+ , Ge2+ and at least one of Yb 2+ and Eu 2+ ; X is a halogen anion selected from at least one of Cl - , Br - and I - ; the structural general formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, where B is an organic amine cation selected from CH3(CH2) n-2 NH3 + or [NH3(CH2) n NH3] 2+ , where n≥2, M is a divalent metal cation selected from at least one of Pb 2+ , Sn 2+ , Cu 2+ , Ni 2+ , Cd 2+ , Cr 2+ , Mn 2+ , Co 2+ , Fe 2+ , Ge 2+ , Yb 2+ and Eu 2+ ; X is a halogen anion selected from at least one of Cl - , Br - and I - .

[0036] The thin film material solution further includes a solvent for providing a liquid environment to disperse the host material. It can be understood that different solvents can be used in the thin film material solutions corresponding to different host materials. In some embodiments, when the host material includes the N-type semiconductor material, the solvent may include at least one of alcohol solvents; for example, at least one of alcohols having 1 to 5 carbon atoms; for example, methanol, ethanol, isopropanol, n-butanol, pentanol, and the like. In some other embodiments, when the host material includes the P-type semiconductor material, the solvent may include one or more of chlorobenzene, toluene, and xylene. In still some other embodiments, when the host material includes the luminescent material, the solvent may include one or more of alkane solvents having 8 to 16 carbon atoms and cycloalkane solvents having 5 to 16 carbon atoms; the alkane solvents having 8 to 16 carbon atoms are selected from one or more of octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, 2-methyl octane, 3-ethyl heptane, 2,2-dimethyl octane, and 1-cyclohexyl decane; the cycloalkane solvents having 5 to 16 carbon atoms are selected from one or two of cyclooctane, cycloheptane, cyclohexane, and cyclopentane.

[0037] In some embodiments, the temperature of the gas flow is 100 to 500 °C; for example, it can be 100 °C, 200 °C, 300 °C, 400 °C, 500 °C, and values between any two of the above. Controlling the temperature within this range can quickly and effectively achieve the heat treatment of the liquid film 104. In other embodiments, the temperature of the gas flow is 150 to 350 °C.

[0038] In some embodiments, the gas forming the gas flow includes an inert gas with a thermal conductivity greater than or equal to 0.01 W / (m·°C); the inert gas with a thermal conductivity within this range has better thermal conductivity. Using it to form a gas flow can better conduct heat, create a heat treatment environment with a uniform temperature distribution for the liquid film 104, help heat the liquid film 104 faster, more fully, and more evenly, promote the full and rapid volatilization of the solvent, avoid film cracking caused by uneven heating temperature, and also avoid residues of impurities in the solvent, such as crystal water, etc., so as to achieve the effect of removing impurities in the film. It can be understood that the thermal conductivity involved in this article refers to the gas thermal conductivity of a substance under the conditions of 0 °C and 101.325 kPa.

[0039] In some specific embodiments, the gas forming the gas flow includes one or more of helium, argon, and nitrogen. For example, the thermal conductivity of helium is 0.144 W / (m·°C), the thermal conductivity of argon is 0.0173 W / (m·°C), and the thermal conductivity of nitrogen is 0.0228 W / (m·°C). In one embodiment, the gas forming the gas flow is helium, and helium has extremely strong heat transfer performance. During the heat treatment of the gas flow, it can more effectively transfer heat to all parts of the film, making each part of it evenly heated.

[0040] In some embodiments, the treatment time is 10 to 60 min; for example, it can be 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, and values between any two of the above, which helps to promote the full volatilization of the solvent in the liquid film 104.

[0041] There can be various choices for the flow direction of the gas flow. According to the different flow directions of the gas flow, different names can be given to the gas flow. In some embodiments, the gas flow includes a first gas flow 101, please refer to Figure 3, the flow direction of the first air flow 101 intersects with the surface of the liquid film 104. That is to say, there is an air flow in the air flow that flows along the direction intersecting with the surface of the liquid film 104, which is named the first air flow 101. It can be understood that the surface of the liquid film 104 refers to its liquid surface, and its specific orientation is determined according to the orientation and state of the liquid film 104. Usually, the liquid film 104 is formed on a horizontal plane, and the surface of the liquid film 104 is a plane parallel to the horizontal plane. For the convenience of description, the following will take the liquid film 104 formed on a horizontal plane as an example for illustration. The first air flow 101 flows along the direction intersecting with the horizontal plane, which can reduce the surface tension of the liquid film 104 in the horizontal direction, thereby reducing the generation of the coffee ring effect and improving the film-forming effect of the thin film. In some other embodiments, the flow direction of the first air flow 101 is perpendicular to the surface of the liquid film 104; in this way, the surface tension of the liquid film 104 in the horizontal direction can be better reduced, and the film-forming effect of the thin film can be improved.

[0042] In some embodiments, the gas flow rate of the first air flow 101 is 0.5 - 100 sccm; for example, it can be 0.5 sccm, 1 sccm, 2 sccm, 3 sccm, 5 sccm, 10 sccm, 15 sccm, 20 sccm, 25 sccm, 30 sccm, 35 sccm, 40 sccm, 45 sccm, 50 sccm, 60 sccm, 70 sccm, 80 sccm, 90 sccm, 100 sccm and the values between any two of the above, which helps to regulate the treatment intensity of the first air flow 101 on the surface of the liquid film 104 and helps to better improve the coffee ring effect. It can be understood that the gas flow rate involved in this article refers to the volume flow rate of the gas under normal temperature and pressure (20 - 30 °C, 101.325 kPa).

[0043] In some embodiments, the air flow further includes a second air flow 102 and a third air flow 103. Please refer to Figure 3 and Figure 4 , the flow direction of the second air flow 102 is parallel to the surface of the liquid film 104, the flow direction of the third air flow 103 is parallel to the surface of the liquid film 104, and the flow direction of the second air flow 102 intersects with the flow direction of the third air flow 103. The intersecting second air flow 102 and third air flow 103 form a cross air flow on the surface of the liquid film 104, which can break the non-uniformity of the surface of the liquid film 104, make the liquid more evenly distributed on the film surface, thereby reducing the generation of the coffee ring effect and further improving the film-forming effect of the thin film.

[0044] In some embodiments, the included angle α formed by the flow direction of the second air flow 102 and the flow direction of the third air flow 103 is 85° to 95°; for example, it can be 85°, 86°, 87°, 88°, 89°, 90°, 91°, 92°, 93°, 94°, 95°, and values between any two of the above, which helps to better improve the uniformity of the surface of the liquid film 104.

[0045] In some embodiments, the gas flow rate of the second air flow 102 is 0.5 to 100 sccm; for example, it can be 0.5 sccm, 1 sccm, 2 sccm, 3 sccm, 5 sccm, 10 sccm, 15 sccm, 20 sccm, 25 sccm, 30 sccm, 35 sccm, 40 sccm, 45 sccm, 50 sccm, 60 sccm, 70 sccm, 80 sccm, 90 sccm, 100 sccm, and values between any two of the above; in some embodiments, the gas flow rate of the third air flow 103 is 0.5 to 100 sccm; for example, it can be 0.5 sccm, 1 sccm, 2 sccm, 3 sccm, 5 sccm, 10 sccm, 15 sccm, 20 sccm, 25 sccm, 30 sccm, 35 sccm, 40 sccm, 45 sccm, 50 sccm, 60 sccm, 70 sccm, 80 sccm, 90 sccm, 100 sccm, and values between any two of the above; this helps to regulate the treatment intensity of the parallel cross air flow on the surface of the liquid film 104 and helps to better improve the coffee ring effect.

[0046] In some embodiments, when the air flow includes the first air flow 101, the second air flow 102, and the third air flow 103, the gas flow rate of the first air flow 101 is 5 to 50 sccm; for example, it can be 5 sccm, 10 sccm, 15 sccm, 20 sccm, 25 sccm, 30 sccm, 35 sccm, 40 sccm, 45 sccm, 50 sccm, and values between any two of the above. When the three air flows exist simultaneously, further regulating the flow rate of the first air flow 101 within the above range helps to eliminate the vortices formed when the second air flow 102 and the third air flow 103 cross, thereby better exerting the role of the air flow, better improving the thickness uniformity of the surface of the liquid film 104, and improving the film-forming effect.

[0047] In some embodiments, when the liquid film 104 is placed in an air stream for treatment to obtain a thin film, the liquid film 104 is irradiated with ultraviolet light when it is placed in the air stream. Under the irradiation of ultraviolet light, it helps to promote rapid film formation, can improve production efficiency, reduce the production cycle, save energy costs, and at the same time, it can also play a role in accelerating positive aging and improving the durability of the thin film. In addition, it can also improve the adhesion between the thin film and its substrate material, enhance the bonding property between them, thereby further improving the anti-solubility and wear resistance of the thin film, so that it can better resist the erosion, wear and corrosion of chemical substances.

[0048] In some embodiments, the wavelength of the ultraviolet light is 360 - 370 nm; for example, it can be 360 nm, 362 nm, 364 nm, 365 nm, 366 nm, 367 nm, 369 nm, 370 nm, and the values between any two of the above, which helps to better promote rapid film formation.

[0049] In some embodiments, the time for irradiating the liquid film 104 with ultraviolet light is 10 - 60 min; for example, it can be 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, and the values between any two of the above, which helps to promote rapid film formation.

[0050] In some embodiments, the power density of the ultraviolet light is 0.01 - 500 W / cm 2 ; for example, it can be 0.01 W / cm 2 、0.05 W / cm 2 、0.1 W / cm 2 、0.5 W / cm 2 、1 W / cm 2 、2 W / cm 2 、3 W / cm 2 、4 W / cm 2 、5 W / cm 2 、8 W / cm 2 、10 W / cm 2 、20 W / cm 2 、30 W / cm 2 、50 W / cm 2 、70 W / cm 2 、100 W / cm 2 、120 W / cm 2 、150 W / cm 2 、180 W / cm 2 、200 W / cm 2 、230 W / cm 2 、250 W / cm 2, 280 W / cm 2 , 300 W / cm 2 , 330 W / cm 2 , 350 W / cm 2 , 380 W / cm 2 , 400 W / cm 2 , 420 W / cm 2 , 450 W / cm 2 , 480 W / cm 2 , 500 W / cm 2 And values between any two of the above, controlling the power density of ultraviolet light within this range helps to better exert the treatment effect of ultraviolet light.

[0051] In some embodiments, the thin film material solution may further include a crosslinking agent. By adding the crosslinking agent, it can prompt the crosslinking agent and the thin film material to undergo a crosslinking reaction to form a crosslinking network, which plays a role in improving the film-forming effect. Further, in combination with ultraviolet light irradiation, it can promote the crosslinking reaction in the thin film, which helps to better improve the physical properties of the thin film, such as hardness, wear resistance, and chemical resistance, etc. In one embodiment, the crosslinking agent may include, but is not limited to, one or more of silicone compounds and organosilane compounds; the silicone compound includes 1,3,5,7-tetramethyl-1,3,5,7-tetramethoxycyclotetrasiloxane, and the organosilane compound includes one or more of 3-methylpropylsilane and 3-methoxypropylsilane. In the thin film material solution, the mass percentage content of the first crosslinking agent is 1-20%; for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20% and values between any two of the above, which helps to improve the film-forming effect.

[0052] In some embodiments, the thin film material solution further includes a photosensitizer. By adding the photosensitizer, it helps to eliminate the influence of photoaging and improve the durability of the thin film. Further, in combination with ultraviolet light irradiation, it can promote the photosensitizer in the thin film to absorb light energy and convert it into other forms of energy, better weakening the influence of photoaging. The photosensitizer can be added to the thin film material solution with a luminescent material as the main material to better improve the durability of the light-emitting layer 30. Specifically, in one embodiment, the photosensitizer may include, but is not limited to, dimethylformamide (DMAA), tetramethyltetrazacyclopentane (TMAH), etc. In the thin film material solution, the mass percentage content of the photosensitizer is 0-20%; for example, 0.001%, 0.01%, 0.1%, 1%, 2%, 3%, 5%, 8%, 10%, 13%, 15%, 17%, 19%, 20% and values between any two of the above.

[0053] The thin film prepared by the preparation method proposed in this application has a low surface roughness, good film-forming effect, low impurity content, is not easy to crack, and has better semiconductor characteristics, stability and repeatability.

[0054] In a second aspect, this application proposes a thin film prepared by the preparation method described above.

[0055] In a third aspect, this application also proposes an optoelectronic device 100, including but not limited to an organic light-emitting diode, a quantum dot light-emitting diode, a photovoltaic cell, a photodetector, etc. The optoelectronic device 100 can be a normal device or an inverted device.

[0056] Please refer to Figure 2 , the optoelectronic device 100 includes a first electrode, one or more functional layers and a second electrode stacked. Among the one or more functional layers, at least one of the functional layers includes the thin film prepared by the preparation method described above. The first electrode is selected from one of the anode 10 and the cathode 20, and the second electrode is selected from the other of the anode 10 and the cathode 20.

[0057] Since at least one functional layer is treated by the above method, the film-forming effect and cracking rate of the functional layer are well improved, making it have good semiconductor characteristics, which is beneficial to the preparation of subsequent film layers, improves the film-forming effect of subsequent film layers, and further helps to improve the repeatability, stability and optoelectronic performance of the device.

[0058] The first electrode is selected from a doped metal oxide particle electrode, a composite electrode of a metal and a metal oxide, a graphene electrode, a carbon nanotube electrode, a metal electrode or an alloy electrode. The material of the doped metal oxide particle electrode is selected from one or more of indium-doped tin oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, indium-doped zinc oxide, magnesium-doped zinc oxide and aluminum-doped magnesium oxide. The composite electrode of a metal and a metal oxide is selected from AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, TiO2 / Ag / TiO2, TiO2 / Al / TiO2, ZnS / Ag / ZnS, ZnS / Al / ZnS. The material of the metal electrode is selected from one or more of Ag, Al, Cu, Mo, Au, Pt, Si, Ca, Mg and Ba. Among them, " / " represents a stacked structure. For example, the composite electrode AZO / Ag / AZO represents an electrode with a three-layer stacked composite structure composed of an AZO layer, an Ag layer and an AZO layer.

[0059] The second electrode is selected from a doped metal oxide particle electrode, a composite electrode of a metal and a metal oxide, a graphene electrode, a carbon nanotube electrode, a metal electrode or an alloy electrode. The material of the doped metal oxide particle electrode is selected from one or more of indium-doped tin oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, indium-doped zinc oxide, magnesium-doped zinc oxide, and aluminum-doped magnesium oxide. The composite electrode of a metal and a metal oxide is selected from AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, TiO2 / Ag / TiO2, TiO2 / Al / TiO2, ZnS / Ag / ZnS, ZnS / Al / ZnS. The material of the metal electrode is selected from one or more of Ag, Al, Cu, Mo, Au, Pt, Si, Ca, Mg, and Ba. Herein, " / " represents a laminated structure. For example, the composite electrode AZO / Ag / AZO represents an electrode with a three-layer laminated composite structure composed of an AZO layer, an Ag layer, and an AZO layer.

[0060] The one or more functional layers are selected from one or more of a light-emitting layer 30, a hole-transporting layer 40, a hole-injecting layer 50, and an electron-transporting layer 60. When the one or more functional layers are composed of the light-emitting layer 30, the hole-transporting layer 40, the hole-injecting layer 50, and the electron-transporting layer 60, the film layer structure of the optoelectronic device 100 is as follows: an anode 10, a hole-injecting layer 50, a hole-transporting layer 40, a light-emitting layer 30, an electron-transporting layer 60, and a cathode 20 are sequentially laminated, or a cathode 20, an electron-transporting layer 60, a light-emitting layer 30, a hole-transporting layer 40, a hole-injecting layer 50, and an anode 10 are sequentially laminated. It can be understood that when one or more of the above functional layers are omitted, the remaining film layers are still arranged in the above lamination order. For example, when the optoelectronic device 100 does not include the electron-transporting layer 60, the remaining film layers included therein are laminated in the following order: an anode 10, a hole-injecting layer 50, a hole-transporting layer 40, a light-emitting layer 30, and a cathode 20 are sequentially laminated, or a cathode 20, a light-emitting layer 30, a hole-transporting layer 40, a hole-injecting layer 50, and an anode 10 are sequentially laminated.

[0061] Among them, the material of the light-emitting layer 30 includes one or more of an organic light-emitting material and a quantum dot light-emitting material. The material of the electron-transporting layer 60 includes the N-type semiconductor material. The material of the hole-transporting layer 40 includes the first material. The material of the hole-injecting layer 50 includes the second material. The light-emitting material, the N-type semiconductor material, the first material, and the second material have all been described in detail above and will not be elaborated herein.

[0062] At least one of the light-emitting layer 30, the hole-transporting layer 40, the hole-injecting layer 50, and the electron-transporting layer 60 is prepared by the preparation method described above.

[0063] It can be understood that the optoelectronic device 100 can also be provided with some functional layers that are conventionally used in optoelectronic devices 100 and are helpful for improving the performance of the optoelectronic device 100, such as an electron-blocking layer, a hole-blocking layer, an interface modification layer, etc.

[0064] It can be understood that the materials of the respective layers of the optoelectronic device 100 can be adjusted according to the actual requirements of the optoelectronic device 100.

[0065] It can be understood that the optoelectronic device 100 can also include a packaging layer (not shown in the figure) to isolate water and oxygen (for example, to make the concentrations of oxygen and water lower than 0.1 ppm) and improve the performance stability of the optoelectronic device 100. Specifically, the packaging material used to form the packaging layer can be selected from at least one of UV glue, metal thin film, and glass glue, etc. In a specific embodiment, the packaging material can be acrylic resin or epoxy resin.

[0066] Based on the above optoelectronic device 100, a preparation method of the optoelectronic device 100 is further proposed. The preparation method includes: sequentially preparing a plurality of film layers according to a preset film layer sequence to obtain the optoelectronic device 100; wherein, the plurality of film layers include a first electrode, a second electrode, and one or more functional layers; when preparing one or more functional layers, at least one of the functional layers is prepared by using the above-mentioned preparation method of the thin film.

[0067] Wherein, the preset film layer sequence refers to the sequence in which the optoelectronic device 100 is stacked layer by layer from bottom to top.

[0068] In the optoelectronic device 100 provided in the present application, at least one of the one or more functional layers is prepared by using the above-mentioned preparation method of the thin film, and for other functional layers, the first electrode, and the second electrode, conventional preparation methods can also be used for preparation. Specifically, the conventional preparation methods can be chemical methods or physical methods. Among them, the chemical methods include chemical vapor deposition method, sequential ionic layer adsorption and reaction method, anodic oxidation method, electrolytic deposition method, co-precipitation method. The physical methods include physical coating method and solution method. Among them, the physical coating method includes: thermal evaporation coating method, electron beam evaporation coating method, magnetron sputtering method, multi-arc ion coating method, physical vapor deposition method, atomic layer deposition method, pulsed laser deposition method, etc.; the solution method can be spin coating method, printing method, inkjet printing method, blade coating method, printing method, dip coating method, immersion method, spraying method, roll coating method, casting method, slot die coating method, and bar coating method, etc.

[0069] In some embodiments, after the optoelectronic device 100 is prepared, it further includes a step of encapsulating the optoelectronic device 100. The encapsulation process can be carried out by using common machine encapsulation or manual encapsulation. Preferably, in the environment of the encapsulation process, both the oxygen content and the water content are lower than 0.1 ppm to ensure the stability of the optoelectronic device 100.

[0070] Fourthly, the present application also relates to a display device, and the display device includes the optoelectronic device 100 provided by the present application. The display device can be any electronic product with a display function, and the electronic products include but are not limited to smart phones, tablet computers, laptop computers, digital cameras, digital video cameras, smart wearable devices, smart weighing electronic scales, in-vehicle displays, televisions or e-book readers. Among them, the smart wearable devices can be, for example, smart bracelets, smart watches, virtual reality (VR) helmets, etc.

[0071] The present application will be specifically described below through specific embodiments. The following embodiments are only partial embodiments of the present application and do not limit the present application. The raw materials used in the following embodiments are all commercially available products without special instructions.

[0072] Thin Film Example 1

[0073] (1) Green quantum dots (emission peak wavelength: 545 nm) are dispersed in n-hexane to prepare a thin film material solution with a quantum dot concentration of 12 mg / mL for standby.

[0074] (2) A glass substrate is placed in a chamber, and a helium gas flow is introduced into the chamber. The direction of the gas flow is perpendicular to the substrate surface, the gas flow temperature is 30 °C, and the gas flow rate of the gas is 10 sccm. The thin film material solution is taken and dropped on the substrate, and spin-coated at a speed of 3000 rpm for 30 s and then left standing for 15 min to obtain a thin film with a thickness of 20 nm.

[0075] Thin Film Example 2

[0076] The solution of this embodiment is basically the same as that of Example 1, except that in this embodiment:

[0077] In step (2), the gas flow temperature is changed to 300 °C.

[0078] Thin Film Example 3

[0079] The solution of this embodiment is basically the same as that of Example 1, except that in this embodiment:

[0080] In step (2), the helium gas flow consists of a first gas flow, a second gas flow, and a third gas flow. Among them, the direction of the first gas flow is perpendicular to the substrate surface, the gas flow rate of the first gas flow is 10 sccm, the gas flow directions of the second gas flow and the third gas flow are both parallel to the substrate surface, and the gas flow directions of the second gas flow and the third gas flow are perpendicular to each other. The gas flow rate of the second gas flow is 10 sccm, and the gas flow rate of the third gas flow is 10 sccm.

[0081] Thin film Example 4

[0082] The solution of this example is basically the same as that of Example 1, except that in this example:

[0083] In step (2), the gas flow temperature is changed to 300 °C. And the helium gas flow consists of a first gas flow, a second gas flow, and a third gas flow. Among them, the direction of the first gas flow is perpendicular to the substrate surface, the gas flow rate of the first gas flow is 10 sccm, the gas flow directions of the second gas flow and the third gas flow are both parallel to the substrate surface, and the gas flow directions of the second gas flow and the third gas flow are perpendicular to each other. The gas flow rate of the second gas flow is 10 sccm, and the gas flow rate of the third gas flow is 10 sccm.

[0084] Thin film Example 5

[0085] The solution of this example is basically the same as that of Example 4, except that in this example:

[0086] In step (2), an ultraviolet lamp is also provided in the chamber, and during the process of step (2), the ultraviolet lamp is turned on, and the liquid film on the substrate is irradiated with ultraviolet light. The power density of the ultraviolet light is 10 W / cm 2 .

[0087] Thin film Example 6

[0088] The solution of this example is basically the same as that of Example 5, except that in this example:

[0089] In step (2), the gas flow rate of the first gas flow is changed to 5 sccm.

[0090] Thin film Example 7

[0091] The solution of this example is basically the same as that of Example 5, except that in this example:

[0092] In step (2), the gas flow rate of the first gas flow is changed to 50 sccm.

[0093] Thin film Example 8

[0094] The solution of this example is basically the same as that of Example 5, except that in this example:

[0095] In step (2), the gas flow rate of the first gas stream is changed to 55 sccm.

[0096] Thin film Example 9

[0097] The solution of this example is basically the same as that of Example 5, except that in this example:

[0098] In step (2), the first gas stream is cancelled, and the gas stream is only composed of the second gas stream and the third gas stream.

[0099] Thin film Example 10

[0100] The solution of this example is basically the same as that of Example 5, except that in this example:

[0101] In step (2), the helium gas stream is changed to an argon gas stream.

[0102] Thin film Example 11

[0103] The solution of this example is basically the same as that of Example 5, except that in this example:

[0104] In step (2), the helium gas stream is changed to a nitrogen gas stream.

[0105] Thin film Example 12

[0106] The solution of this example is basically the same as that of Example 5, except that in this example, the thin film is a 70-nm-thick TFB thin film. Correspondingly, step (1) is changed to: Disperse TFB in chlorobenzene to prepare a thin film material solution with a TFB concentration of 10 mg / mL for standby.

[0107] In step (2), the temperature of the helium gas stream is changed to 300 °C.

[0108] Thin film Example 13

[0109] The solution of this example is basically the same as that of Example 5, except that in this example, the thin film is a 70-nm-thick ZnO thin film. Correspondingly, step (1) is changed to: Disperse ZnO nanoparticles in ethanol to prepare a thin film material solution with a ZnO concentration of 30 mg / mL for standby.

[0110] In step (2), the temperature of the helium gas stream is changed to 300 °C.

[0111] Thin film Example 14

[0112] The solution of this embodiment is basically the same as that of Embodiment 13, except that in this embodiment, in step (1), the thin film material solution further includes the crosslinking agent 3-methylpropylsilane. Specifically, step (1) is changed to dispersing ZnO nanoparticles and the crosslinking agent in ethanol to prepare a thin film material solution with a ZnO concentration of 30 mg / mL for standby. In the solution, the mass percentage content of the crosslinking agent is 10%.

[0113] Thin Film Embodiment 15

[0114] The solution of this embodiment is basically the same as that of Embodiment 13, except that in this embodiment, in step (1), the thin film material solution further includes the photosensitizer dimethylamine formamide (DMAA). Specifically, step (1) is changed to dispersing ZnO nanoparticles and the photosensitizer in ethanol to prepare a thin film material solution with a ZnO concentration of 30 mg / mL for standby. In the solution, the mass percentage content of the photosensitizer is 10%.

[0115] Thin Film Comparative Example 1

[0116] The solution of this comparative example is basically the same as that of Embodiment 1, except that this comparative example is a thin film prepared by heat treatment on a hot plate. Correspondingly, in the preparation method, step (2) is changed to: taking a glass substrate, taking the thin film material solution, dropping it on the substrate, spin-coating at a speed of 3000 rpm for 30 s, and then placing the substrate on the hot plate for heating. The heating temperature is 30 °C and the heating time is 5 min to obtain a thin film with a thickness of 20 nm.

[0117] Thin Film Comparative Example 2

[0118] The solution of this comparative example is basically the same as that of Embodiment 1, except that in this comparative example, only ultraviolet light irradiation treatment is used. Correspondingly, step (2) is changed to:

[0119] Taking a glass substrate and placing it in a chamber. An ultraviolet lamp is also provided in the chamber. Turning on the ultraviolet lamp, taking the thin film material solution, dropping it on the substrate, spin-coating at a speed of 3000 rpm for 30 s, and standing for 5 min under ultraviolet light irradiation to obtain a thin film with a thickness of 20 nm.

[0120] Thin Film Comparative Example 3

[0121] The solution of this comparative example is basically the same as that of Comparative Example 1, except that this comparative example is a TFB thin film. Correspondingly, step (1) is changed to: dispersing TFB in chlorobenzene to prepare a thin film material solution with a TFB concentration of 10 mg / mL for standby.

[0122] In step (2), the heating temperature of the hot plate is changed to 300 °C.

[0123] Thin Film Comparative Example 4

[0124] This comparative example is basically the same as Comparative Example 1, except that in this comparative example, it is a ZnO thin film. Correspondingly, step (1) is changed to: Disperse ZnO nanoparticles in ethanol to prepare a thin film material solution with a ZnO concentration of 30 mg / mL for standby.

[0125] In step (2), the temperature of heating by the hot plate is changed to 300 °C.

[0126] Device Example 1

[0127] (1) Provide an ITO anode with a thickness of 10 nm.

[0128] (2) Spin-coat the PEDOT:PSS material on the anode at 3000 rpm for 30 s, and then heat it with a hot plate at 100 °C for 10 min to obtain a hole injection layer with a thickness of 100 nm.

[0129] (3) Transfer the substrate obtained in step (2) to a nitrogen atmosphere, take a 10 mg / ml chlorobenzene solution of TFB, drop it on the surface of the hole injection layer, spin-coat it at 3000 rpm for 30 s, and then heat it with a hot plate at 150 °C for 30 min to obtain a hole transport layer with a thickness of 70 nm.

[0130] (4) Referring to the method of Film Example 1, prepare a thin film on the hole transport layer to obtain a light-emitting layer with a thickness of 20 nm.

[0131] (5) Take a 30 mg / ml ZnO ethanol solution, drop it on the light-emitting layer, spin-coat it at 3000 rpm for 30 s, and then heat it with a hot plate at 80 °C for 30 min to obtain an electron transport layer with a thickness of 70 nm.

[0132] (6) Put the semi-finished device made in step (5) into a vacuum coater, and pump the vacuum to 3×10 -4 mbar, turn on the Ag target, and the Ag target evaporates at a rate of for 200 s to obtain a cathode with a thickness of 30 nm, and then encapsulate it to obtain a QLED device.

[0133] Device Examples 2 to 11

[0134] The scheme of Device Example n is basically the same as that of Device Example 1, except that in step (4) of Device Example n, referring to the method of Film Example n, a thin film is prepared on the hole transport layer to form the corresponding light-emitting layer. n is any integer from 2 to 11.

[0135] Device Example 12

[0136] The solution of this device embodiment is basically the same as that of Device Embodiment 1, except that in this device embodiment, the hole transport layer is a film prepared by using the film preparation method of the present application, and the light-emitting layer is a film prepared by heating with a heating plate. Specifically, steps (3) and (4) are changed to:

[0137] (3) Referring to the method of Film Embodiment 12, a film is prepared on the hole injection layer to obtain a hole transport layer with a thickness of 70 nm.

[0138] (4) The film material solution prepared in Film Embodiment 1 is spin-coated on the hole transport layer at a speed of 3000 rpm for 30 s, and then it is heated with a heating plate and treated at 80 °C for 5 min to obtain a light-emitting layer with a thickness of 20 nm.

[0139] Device Embodiment 13

[0140] The solution of this device embodiment is basically the same as that of Device Embodiment 1, except that in this device embodiment, the electron transport layer is a film prepared by using the film preparation method of the present application, and the light-emitting layer is a film prepared by heating with a heating plate. Specifically, steps (4) and (5) are changed to:

[0141] (4) The film material solution prepared in Film Embodiment 1 is spin-coated on the hole transport layer at a speed of 3000 rpm for 30 s, and then it is heated with a heating plate and treated at 80 °C for 5 min to obtain a light-emitting layer with a thickness of 20 nm.

[0142] (5) Referring to the method of Film Embodiment 13, a film is prepared on the light-emitting layer to obtain an electron transport layer with a thickness of 70 nm.

[0143] Device Embodiment 14

[0144] The solution of this device embodiment is basically the same as that of Device Embodiment 13, except that in step (5) of this device embodiment, referring to the method of Film Embodiment 14, an electron transport layer is prepared on the light-emitting layer.

[0145] Device Embodiment 15

[0146] The solution of this device embodiment is basically the same as that of Device Embodiment 13, except that in step (5) of this device embodiment, referring to the method of Film Embodiment 15, an electron transport layer is prepared on the light-emitting layer.

[0147] Device Embodiment 16

[0148] The solution of this device embodiment is basically the same as that of Device Embodiment 1, except that in this device embodiment, the hole transport layer, the electron transport layer, and the light-emitting layer are all films prepared by using the film preparation method of the present application. Specifically, steps (3) and (5) are changed to:

[0149] (3) Refer to the method of Film Example 12, prepare a film on the hole injection layer to obtain a hole transport layer with a thickness of 70 nm.

[0150] (5) Refer to the method of Film Example 13, prepare a film on the light-emitting layer to obtain an electron transport layer with a thickness of 70 nm.

[0151] Device Comparative Example 1

[0152] The device comparative example scheme is basically the same as that of Device Example 1, except that in this device comparative example, the hole transport layer, the electron transport layer, and the light-emitting layer are all films prepared by heating with a hot plate. Correspondingly, step (4) is changed to: Spin-coat the film material solution prepared in Film Example 1 on the hole transport layer, spin-coat at a speed of 3000 rpm for 30 s, and then heat it with a hot plate, treat it at 80 °C for 30 min to obtain a light-emitting layer with a thickness of 20 nm.

[0153] Device Comparative Example 2

[0154] The device comparative example scheme is basically the same as that of Device Comparative Example 1, except that in this device comparative example, the light-emitting layer is a film prepared only by ultraviolet light irradiation treatment. Correspondingly, in step (4):

[0155] Refer to the method of Film Comparative Example 2 to prepare a film on the hole transport layer to form the corresponding light-emitting layer.

[0156] Experimental Example

[0157] (1) Take the films prepared in the above film examples and film comparative examples, detect their properties, and the results are shown in Table 1. The detection method is:

[0158] (1) Observe the film surface by atomic force microscope (AFM) to detect the surface roughness Ra of the film.

[0159] (2) For each example or comparative example, prepare the film 10 times according to its preparation method, detect the film cracking rate, and the cracking rate = the number of films with cracks / 10 * 100%.

[0160] Table 1

[0161]

[0162]

[0163] Please refer to Table 1, and it can be seen that:

[0164] The cracking rates of Film Examples 1 to 11 are lower than those of Film Comparative Examples 1 and 2. The cracking rate of Film Example 12 is lower than that of Film Comparative Example 3. The cracking rates of Film Examples 13 to 15 are lower than that of Film Comparative Example 4. In addition, each film example has a surface roughness not higher than that of its corresponding film comparative example, indicating that the preparation method of the present application helps to improve the film-forming quality and reduce the cracking rate of the film. In particular, Film Example 5 has extremely low surface roughness and cracking rate, indicating that treating the film by the method of hot helium gas + three airflows + ultraviolet light can significantly improve the film-forming effect of the film and obtain a film with uniform thickness and not easy to crack.

[0165] In addition, by comparing Film Examples 5, 8 and 9, it can be seen that Film Example 5 has significantly lower surface roughness, indicating that the combination of the first airflow, the second airflow and the third airflow can better reduce the coffee ring effect and improve the film-forming effect. Further controlling the flow rate of the first airflow within the range of 5 - 50 sccm helps to better exert the role of the airflow and improve the thickness uniformity of the liquid film surface.

[0166] (2) Performance testing was carried out on the devices obtained in the above device examples and device comparative examples. The results are recorded in Table 2. The testing method is as follows:

[0167] (1) An efficiency testing system was built using a Fosida FPD optical property measurement device (including Ocean Optics USB2000, LabView-controlled QE-PRO spectrometer, Keithley 2400, high-precision digital source meter Keithley 6485, optical fiber with an inner diameter of 50 μm, device test probes and fixtures, various related connection wires and data cards, efficiency test dark box and data acquisition system, etc.) to detect and obtain parameters such as the turn-on voltage, current, brightness (L), and emission spectrum of each optoelectronic device. Then, key parameters such as external quantum efficiency and power efficiency were calculated, and the service life of each of the above optoelectronic devices was tested using a life testing device.

[0168] (2) Among them, the testing method for current efficiency is as follows: Set the luminous area to 2 mm × 2 mm = 4 mm 2 , and intermittently collect the brightness values of the optoelectronic device within the range of driving voltage from 0 V to 8 V. The initial voltage value for collecting brightness is 3 V, and it is collected every 0.2 V. The brightness value collected each time is divided by the corresponding current density to obtain the current efficiency of the optoelectronic device under the collection conditions of that time, and the maximum current efficiency (C.Emax, cd / A) is obtained.

[0169] (3) The test method for service life is as follows: Under the drive of a constant current (2 mA), use a 128-channel QLED life test system to conduct electroluminescence life analysis on each optoelectronic device, record the time (T95, h) required for each optoelectronic device to decay from the maximum brightness to 95%, and calculate the time (T95@1000nit, h) required for the brightness of each optoelectronic device to decay from 100% to 95% at a brightness of 1000 nit through the decay fitting formula.

[0170] Table 2

[0171]

[0172]

[0173] Referring to Table 2, it can be seen that:

[0174] The device embodiments have higher EQE, T95_1k nit, and C.E. than Comparative Examples 1 and 2, indicating that the functional film layer of the device prepared by the film of the present application can reduce film layer defects, improve the film-forming effect and semiconductor performance of the film layer to be processed, improve the film-forming effect of the subsequent film layer, and thus improve the stability and optoelectronic performance of the device, which is macroscopically characterized by the improvement of the device life, current efficiency, and external quantum efficiency.

[0175] The technical solutions provided by the embodiments of the present application have been introduced in detail above. Specific examples are used in this article to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A method for preparing a thin film, characterized in that, It includes the following steps: Provide a thin film material solution containing a matrix material; Deposit the thin film material solution to obtain a liquid film; Place the liquid film in an air flow for treatment to obtain a thin film; Wherein, the matrix material includes one or more of an N-type semiconductor material, a P-type semiconductor material, an organic light-emitting material, and a quantum dot light-emitting material.

2. The preparation method according to claim 1, characterized in that, The gas forming the air flow includes an inert gas with a thermal conductivity greater than or equal to 0.01 W / (m·°C); and / or, The temperature of the air flow is 100 - 500 °C; and / or, The time of the treatment is 10 - 60 min; and / or, The air flow includes a first air flow, and the flow direction of the first air flow intersects with the surface of the liquid film.

3. The preparation method according to claim 2, characterized in that, The flow direction of the first air flow is perpendicular to the surface of the liquid film; and / or, The gas flow rate of the first air flow is 0.5 - 100 sccm; and / or, The gas forming the air flow includes one or more of helium, argon, and nitrogen; and / or, The air flow further includes a second air flow and a third air flow. The flow direction of the second air flow is parallel to the surface of the liquid film, the flow direction of the third air flow is parallel to the surface of the liquid film, and the flow direction of the second air flow intersects with the flow direction of the third air flow.

4. The preparation method according to claim 3, wherein When the air flow includes the first air flow, the second air flow, and the third air flow, the gas flow rate of the first air flow is 5 - 50 sccm; and / or, The gas flow rate of the second air flow is 0.5 - 100 sccm; and / or, The gas flow rate of the third air flow is 0.5 - 100 sccm; The included angle formed by the flow direction of the second air flow and the flow direction of the third air flow is 85° - 95°.

5. The preparation method according to claim 1, characterized in that, In the step of placing the liquid film in an air flow for treatment to obtain a thin film, when placing the liquid film in the air flow, irradiate the liquid film with ultraviolet light.

6. The preparation method according to claim 5, wherein The time for irradiating the liquid film with ultraviolet light is 10 - 60 min; and / or, The power density of the ultraviolet light is 0.01 to 500 W / cm 2 ; and / or, The wavelength of the ultraviolet light is 360 - 370 nm.

7. The preparation method according to any one of claims 1 to 6, characterized in that, The N-type semiconductor material includes one or more of metal oxides, doped metal oxides, IIB-VIA group materials, IIIB-VA group materials, and IB-IIIB-VIA group materials; the metal oxides include one or more of ZnO, TiO2, and SnO2; the metal oxides in the doped metal oxides include one or more of ZnO, TiO2, and SnO2, and the doping elements include one or more of Al, Mg, Li, In, and Ga; the IIB-VIA group materials include one or more of ZnS, ZnSe, CdS, and CdSe; the IIIB-VA group materials include one or more of InP and GaP; the IB-IIIB-VIA group materials include one or more of CuInS and CuGaS; and / or, The organic light-emitting material includes one or more of 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 material, TTPX fluorescent material, TBRb fluorescent material, DBP fluorescent material, delayed fluorescence material, TTA material, thermally activated delayed material, polymer containing B-N covalent bond, hybrid local charge transfer excited state material, exciplex luminescent material; and / or, The quantum dot light-emitting material includes at least one 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 respectively include at least one 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 at least one 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 at least one 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 at least one 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 at least one 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 Cs + ions, M is a divalent metal cation selected from Pb 2+ , Sn 2+ , Cu 2+ , Ni 2+ 、 Cd 2+ 、 Cr 2+ 、 Mn 2+ 、 Co 2+ 、 Fe 2+ 、 Ge 2+ 、 Yb 2+ 、 Eu 2+ at least one of, X is a halogen anion, selected from Cl−, Br - 、 I - at least one of; the structural general formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, where B is an organic amine cation, selected from CH3(CH2) n-2 NH3 + or [NH3(CH2) n NH3] 2+ , where n≥2, M is a divalent metal cation, selected from Pb 2+ 、 Sn 2+ 、 Cu 2+ 、 Ni 2+ 、 Cd 2+ 、 Cr 2+ 、 Mn 2+ 、 Co 2+ 、 Fe 2+ 、 Ge 2+ 、 Yb 2+ 、 Eu 2+ at least one of, X is a halogen anion, selected from Cl - 、 Br - 、 I - at least one of; and / or, The p-type semiconductor material includes a first material or a second material. The first material includes one or more of 4,4'-N,N'-dicarbazolyl-biphenyl, poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], 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, tris(3-methylphenylphenylamino)-triphenylamine, poly(p-phenylene vinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene], copper phthalocyanine, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compound, N,N,N',N'-tetraarylbenzidine, PEDOT:PSS, poly(N-vinylcarbazole), polymethacrylate, poly(9,9-octylfluorene), poly(spirofluorene), N,N'-bis(naphthalen-1-yl)-N,N'-diphenylbenzidine, spiro-NPB; The second material includes at least one of 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene, PEDOT, PEDOT:PSS, derivative 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.

8. A thin film, characterized in that, Prepared by the preparation method according to any one of claims 1 to 7.

9. An optoelectronic device, characterized in that, It includes a stacked first electrode, one or more functional layers, and a second electrode. In the one or more functional layers, at least one of the functional layers includes a thin film prepared by the preparation method according to any one of claims 1 to 7 or the thin film according to claim 8.

10. The optoelectronic device according to claim 9, wherein, The first electrode is selected from a doped metal oxide particle electrode, a composite electrode of a metal and a metal oxide, a graphene electrode, a carbon nanotube electrode, a metal electrode or an alloy electrode. The material of the doped metal oxide particle electrode is selected from one or more of indium-doped tin oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, indium-doped zinc oxide, magnesium-doped zinc oxide, and aluminum-doped magnesium oxide. The composite electrode of a metal and a metal oxide is selected from AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, TiO2 / Ag / TiO2, TiO2 / Al / TiO2, ZnS / Ag / ZnS, ZnS / Al / ZnS. The material of the metal electrode is selected from one or more of Ag, Al, Cu, Mo, Au, Pt, Si, Ca, Mg, and Ba; and / or, The second electrode is selected from a doped metal oxide particle electrode, a composite electrode of a metal and a metal oxide, a graphene electrode, a carbon nanotube electrode, a metal electrode or an alloy electrode. The material of the doped metal oxide particle electrode is selected from one or more of indium-doped tin oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, indium-doped zinc oxide, magnesium-doped zinc oxide, and aluminum-doped magnesium oxide. The composite electrode of a metal and a metal oxide is selected from AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, TiO2 / Ag / TiO2, TiO2 / Al / TiO2, ZnS / Ag / ZnS, ZnS / Al / ZnS. The material of the metal electrode is selected from one or more of Ag, Al, Cu, Mo, Au, Pt, Si, Ca, Mg, and Ba; and / or, The one or more functional layers are selected from one or more of a light-emitting layer, a hole functional layer, and an electron transport layer. Among them, the material of the light-emitting layer includes one or more of an organic light-emitting material and a quantum dot light-emitting material. The material of the electron transport layer includes the N-type semiconductor material. The material of the hole functional layer includes the P-type semiconductor material. At least one of the light-emitting layer, the hole functional layer, and the electron transport layer is prepared by the preparation method according to any one of claims 1 to 7.

11. A display device, characterized in that, Comprising the optoelectronic device according to claim 9 or 10.

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