Thin film preparation method, photoelectric device and display device

Abstract

The invention discloses a preparation method of a thin film, a photoelectric device and a display device. The preparation method comprises the following steps: providing an initial solid film; and performing terahertz irradiation on the initial solid film to obtain the thin film. Terahertz irradiation is performed on the initial solid-state film, so that the residual solvent in the initial solid-state film can be effectively removed, and the residual solvent is prevented from influencing the performance stability of the film; meanwhile, due to the fact that terahertz irradiation has the characteristics of high frequency selectivity, penetrability, spatial resolution, time resolution, low photo-thermal damage and the like, terahertz waves are adopted for irradiation treatment, and removal of the residual solvent under low power is facilitated; in addition, the terahertz irradiation heat effect is small, ion damage cannot be caused, and the irradiation area, time and temperature can be accurately controlled, so that damage to the thin film material can be avoided as far as possible, and the stability of the thin film is effectively improved.

Description

Technical Field

[0001] The present application relates to the field of optoelectronic technology, and in particular to a method for preparing a thin film, an optoelectronic device and a display device. Background Art

[0002] Semiconductor materials are a type of electronic material that has semiconductor properties and can be used to make semiconductor devices and integrated circuits. Thin films made of semiconductor materials are widely used in the field of optoelectronic technology.

[0003] The current mainstream film-making method is the solution method, which involves coating a solution containing dispersed thin film materials on a substrate to form a liquid film, and then removing the solvent under vacuum to form a solid film. However, the solid film prepared in this way often has residual solvent, which can easily affect the performance stability of the film. Summary of the invention

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

[0005] The embodiment of the present application is implemented as follows:

[0006] In a first aspect, the present application provides a method for preparing a thin film, comprising the following steps:

[0007] providing an initial solid film;

[0008] The initial solid film is subjected to terahertz irradiation to obtain a thin film.

[0009] In a second aspect, the present application proposes a photoelectric device, comprising a first electrode, one or more functional layers and a second electrode, wherein at least one of the one or more functional layers comprises a thin film produced by the preparation method described above.

[0010] In a third aspect, the present application further proposes a display device, which includes the optoelectronic device described above.

[0011] In the technical solution provided in the present application, the initial solid-state film is subjected to terahertz irradiation, which can effectively remove the residual solvent in the initial solid-state film and prevent the residual solvent from affecting the performance stability of the film; at the same time, since terahertz irradiation has the characteristics of high frequency selectivity, penetration, spatial resolution, time resolution and low photothermal damage, the use of terahertz waves for irradiation treatment is helpful to achieve the removal of residual solvent at low power; in addition, terahertz irradiation has a small thermal effect, will not cause ion damage, and can accurately control the irradiation area, time and temperature, so as to avoid damage to the film material as much as possible and effectively improve the stability of the film. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0013] Figure 1 It is a schematic diagram of a process for preparing a thin film proposed in an embodiment of the present application;

[0014] Figure 2 is a schematic structural diagram of an optoelectronic device proposed in one embodiment of the present application;

[0015] Reference numerals:

[0016] 100 - photoelectric device; 10 - anode; 20 - light-emitting layer; 30 - electron transport layer; 40 - cathode; 50 - hole transport layer; 60 - hole injection layer. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0018] In this application, unless otherwise specified, the directional words used, such as "upper" and "lower", refer specifically to the directions of the drawings in the accompanying drawings. In addition, in the description of the specification of this application, the term "including" means "including but not limited to".

[0019] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have 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., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0020] In this application, "and / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural.

[0021] In the present application, "at least one" means one or more, and "plurality" means two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple, respectively.

[0022] In the first aspect, the present invention provides a method for preparing a thin film. Figure 1 , the preparation method comprises the following steps:

[0023] S100, providing an initial solid film;

[0024] S200, performing terahertz irradiation on the initial solid film to obtain a thin film.

[0025] In step S100, the initial solid film refers to a thin film in a solid phase formed by drying a liquid film prepared by a solution method under reduced pressure. Although most of the solvent is removed from this thin film during the process of reduced pressure drying, it is inevitable that some solvent will still remain in the film layer, resulting in unstable performance of the initial solid film. It is understandable that although heat treatment can be used to remove the solvent and avoid solvent residue after the liquid film is prepared, this method has a large thermal effect and causes great damage to the film material, which is not conducive to improving the performance of the film. Therefore, the current mainstream method is still to use the reduced pressure drying method.

[0026] In view of this, in order to further improve the performance of the film, the initial solid film needs to be further treated to remove the solvent.

[0027] In step S200, the terahertz irradiation refers to scanning and irradiating the initial solid film with terahertz waves; the terahertz waves refer to electromagnetic waves with a frequency in the range of 0.1 to 10 THz, which are located in the spectrum region between infrared light and microwaves. Terahertz waves are helpful for the desorption or binding process of atoms or molecules in local materials, especially in some organic semiconductor materials with liquid or volatile components, and are more effective in removing impurities and solvents. Terahertz irradiation of the initial solid film can controllably heat the initial solid film, more effectively remove residual solvents in the initial solid film, avoid residual solvents affecting the performance stability of the film, and optimize the internal structure and performance of the material. Terahertz irradiation has high frequency selectivity and can carry out targeted heating of specific materials and structures, thereby directionally heating the initial solid-state film and accurately controlling the heating area to avoid heating and damaging non-target areas. Terahertz irradiation has high spatial resolution and temporal resolution, which can achieve precise local heating of the target area and achieve precise control of time and temperature during the irradiation process, which helps to further improve the performance of the film. The energy of terahertz radiation is low, and during the heating process, the photothermal damage to the material is small, which can avoid damage to the film material and help to enhance the improvement of the film performance. At the same time, terahertz irradiation is non-ionizing radiation and will not cause ion damage, thus avoiding the impact on the film material and helping to improve the film performance. In addition, terahertz waves have high penetrability and can remove residual solvents at low power when used for film processing.

[0028] In some embodiments, the terahertz irradiation time is 150 to 300 s; for example, it can be 150 s, 160 s, 180 s, 200 s, 220 s, 250 s, 290 s, 300 s and values ​​between any two of the above values; within the irradiation time range of this embodiment, not only can the residual solvent be effectively removed, but the irradiation time is relatively short, and the loss of the thin film material is small.

[0029] In some embodiments, the thickness of the initial solid film is 30-80 nm; for example, it can be 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, and values ​​between any two of the above values.

[0030] In some embodiments, the initial solid film includes a plurality of initial sub-films; accordingly, step S200 can be implemented as follows: terahertz irradiation is performed on the plurality of initial sub-films respectively to obtain a plurality of sub-films, and the plurality of sub-films constitute the thin film.

[0031] When preparing the film, the film can be formed into an initial solid film in one step, and then the complete initial solid film can be subjected to terahertz irradiation. The film can also be split into multiple sub-film layers and prepared separately during preparation. The preparation of each film layer includes: first forming a solid film of the sub-film layer, and then subjecting the solid film to terahertz irradiation; that is, after completing the terahertz irradiation of the previous sub-film layer, forming a solid film of the next sub-film layer on the previous sub-film layer, and then subjecting the solid film of the next sub-film layer to terahertz irradiation, and so on, until the last sub-film layer is prepared. In this way, the residual solvent in the film can be removed more thoroughly, and for the irradiated film, the irradiation time it withstands will be relatively shorter, which can reduce radiation damage and further improve film performance. Exemplarily, in some embodiments, the thin film is prepared by splitting it into three sub-film layers, which are named as the first sub-film layer, the second sub-film layer, and the third sub-film layer for the convenience of description. The thin film is composed of the first sub-film layer, the second sub-film layer, and the third sub-film layer stacked in sequence from bottom to top. Correspondingly, the initial solid-state film includes three initial sub-films, which are named as the first initial sub-film, the second initial sub-film, and the third initial sub-film stacked in sequence from bottom to top. The step of subjecting the initial solid-state film to terahertz irradiation to obtain the thin film in this embodiment includes: first forming a first initial sub-film, and then subjecting the first initial sub-film to terahertz irradiation to obtain a first sub-film layer; then, forming a second initial sub-film on the first sub-film layer, and then subjecting the second initial sub-film to terahertz irradiation to obtain a second sub-film layer; finally, forming a third initial sub-film on the second sub-film layer, and then subjecting the third initial sub-film to terahertz irradiation to obtain a third sub-film layer. The first sub-film layer, the second sub-film layer, and the third sub-film layer together constitute a thin film.

[0032] In some embodiments, the thickness of the initial sub-film is 3 to 40 nm; for example, it can be 3 nm, 5 nm, 8 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, and values ​​between any two of the above values.

[0033] In some embodiments, the initial solid film includes 2 to 10 initial sub-films; for example, there may be 2, 3, 4, 5, 6, 7, 8, 9 or 10 of them.

[0034] The initial sub-film, like the initial solid film, also refers to a thin film in solid phase formed by drying a liquid film prepared by a solution method under reduced pressure.

[0035] In some embodiments, when each of the initial sub-films is subjected to terahertz irradiation, the frequency of the terahertz irradiation is still 0.1 to 10 THz.

[0036] In some embodiments, when each of the initial sub-films is subjected to terahertz irradiation, the terahertz irradiation time is 50 to 200 s, for example, it can be 5 s, 6 s, 10 s, 20 s, 30 s, 50 s, 80 s, 100 s, 120 s, 150 s, 180 s, 200 s, and values ​​between any two of the above values; since the thickness of the initial sub-film is relatively thin, the irradiation time is shortened, and while effectively removing residual solvent, the irradiation damage is reduced, thereby further improving the film performance.

[0037] Furthermore, in some embodiments, in step S200, after the step of terahertz irradiating the initial solid film, before the step of obtaining the thin film, the step further includes: using an electron beam to scan the initial solid film that has been terahertz irradiated. By electron beam annealing the irradiated film, the film damage caused by irradiation can be repaired in a short time. Specifically, taking the embodiment in which the above-mentioned thin film is composed of a first sub-film layer, a second sub-film layer, and a third sub-film layer stacked in sequence from bottom to top as an example, the preparation of the thin film also includes, after the third sub-film layer is prepared, electron beam annealing the composite film layer composed of the first sub-film layer, the second sub-film layer, and the third sub-film layer stacked in sequence from bottom to top.

[0038] In some embodiments, the electron beam is scanned for 5 to 60 seconds; for example, it may be 5 seconds, 6 seconds, 10 seconds, 20 seconds, 30 seconds, 50 seconds, 60 seconds, or any value between any two of the above values; damage can be effectively repaired within this range.

[0039] In some embodiments, the accelerating voltage of the electron beam is 1×10 3 ~8×10 3 K; for example, 1×10 3 K, 2×10 3 K, 3×10 3 K, 4×10 3 K, 5×10 3 K, 6×10 3 K, 7×10 3 K, 8×10 3 K and values ​​between any two of the above values.

[0040] In some embodiments, the electron beam has a beam energy density of 0.5 to 2 J / cm 2 ; For example, it can be 0.5J / cm 2 , 0.8J / cm 2 , 1J / cm 2 , 1.2J / cm 2 , 1.5J / cm 2 , 1.9J / cm 2 , 2J / cm2 and values ​​between any two of the above values.

[0041] In some embodiments, the frequency of the electron beam is 0.5-2 Hz; for example, it can be 0.5 Hz, 0.8 Hz, 1 Hz, 1.3 Hz, 1.5 Hz, 1.7 Hz, 2 Hz, and values ​​between any two of the above values.

[0042] In step S100, the initial solid film can be prepared by a solution method. Specifically, the solution method includes but is not limited to spin coating, drop coating, coating, inkjet printing, scraping, dip pulling, soaking, spraying, rolling, evaporation or casting. Specifically, the preparation steps of the initial solid film can be: depositing a solution of a thin film material on a substrate by a solution method to form a liquid film, and then placing the liquid film in a low-pressure environment or an inert gas flow to remove the solvent to form an initial solid film. The inert gas flow can be a nitrogen flow or an argon flow, etc.; the pressure of the low-pressure environment can be 10 -2 ~10 -3 MPa. The placement time can be 10 to 30 minutes.

[0043] The substrate described herein may also be referred to as a substrate, and its function is to serve as a film-forming carrier for the thin film. Specifically, the substrate may be a prefabricated device or a film layer on which a thin film is to be set in a semi-finished device. For example, when the device structure is cathode 40 / film / anode 10, the surface of cathode 40 or anode 10 may be used as a substrate for preparing the thin film; in addition, the substrate may also be a rigid substrate or a flexible substrate. The rigid substrate may be a ceramic material or various glass materials. The flexible substrate may be a substrate formed of materials such as polyimide film (PI) and its derivatives, polyethylene naphthalate (PEN), phosphoenolpyruvic acid (PEP) or diphenylene ether resin. In one embodiment, the material of the substrate includes glass, silicon wafer, polycarbonate, polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate, polyamide, polyether sulfone, or a combination thereof.

[0044] In some embodiments, the initial solid film can be divided into an electronic functional film with electron transport and injection properties, a hole functional film with hole transport and injection properties, a luminescent film with luminescent properties, and the like according to the different materials thereof. The luminescent film with luminescent properties can be prepared from a luminescent material. The electronic functional film with electron transport properties can also be called an electron transport film, and the material thereof can be a first material with electron transport properties; the electronic functional film with electron injection properties can also be called an electron injection film, and the material thereof can be a second material with electron injection properties. The hole functional film with hole transport properties can also be called a hole transport film, and the material thereof can be a third material with hole transport properties; the hole functional film with hole injection properties can also be called a hole injection film, and the material thereof can be a fourth material with hole injection properties. It can be understood that different solvents can be used for different film materials when preparing the initial solid film.

[0045] In some embodiments, when the material of the initial solid-state film includes the first material or the second material, the initial solid-state film can be used to manufacture the electronic functional layer of the optoelectronic device 100; specifically, when the material of the initial solid-state film includes the first material, the initial solid-state film can be used to manufacture the electron transport layer 30 of the optoelectronic device 100, and when the material of the initial solid-state film includes the second material, the initial solid-state film can be used to manufacture the electron injection layer of the optoelectronic device 100. The first 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 oxide may include but is not limited to one or more of ZnO, TiO2, and SnO2; the metal oxide in the doped metal oxide may include but is not limited to one or more of ZnO, TiO2, and SnO2, and the doping element may include but is not limited to one or more of Al, Mg, Li, In, and Ga; the IIB-VIA group material may include but is not limited to one or more of ZnS, ZnSe, CdS, and CdSe; the IIIB-VA group material may include but is not limited to one or more of InP and GaP; the IB-IIIB-VIA group material may include but is not limited to one or more of CuInS and CuGaS; the second material may include but is not limited to at least one of cesium carbonate, cesium fluoride, cesium azide and lithium fluoride.

[0046] Correspondingly, when preparing the corresponding initial solid film, the solvent used to disperse the thin film material to form the solution of the thin film material includes at least one of the alcohol solvents; for example, including but not limited to at least one of the alcohols with a carbon number of 1 to 5; for example, methanol, ethanol, isopropanol, n-butanol, pentanol, etc.

[0047] In some embodiments, when the material of the initial solid film includes the third material or the fourth material, the initial solid film can be used to prepare the hole functional layer of the optoelectronic device 100; specifically, when the material of the initial solid film includes the third material, the initial solid film can be used to prepare the hole transport layer 50 of the optoelectronic device 100, and when the material of the initial solid film includes the fourth material, the initial solid film can be used to prepare the hole injection layer 60 of the optoelectronic device 100. The third material includes 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[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butyl)phenyl)- phenyl) diphenylamine))] (TFB) and poly (4-butylphenyl-diphenylamine) (poly-TPD), polyaniline, polypyrrole, 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, aromatic tertiary amines, multinuclear One or more of 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) (PVK) and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, N,N'-di(naphthalene-1-yl)-N,N'-diphenylbenzidine (NPB), and spiro NPB.Conventional materials for the hole injection layer 6060 may include, but are not limited to, poly(ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), poly(9,9-dioctyl-fluorene-co-N-(4-butylphenyl)-diphenylamine) (TFB), polyarylamine, poly(N-vinylcarbazole), polyaniline, polypyrrole, N,N,N',N'-tetrakis(4-methoxyphenyl)-benzidine (TPD), 4-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl (α-NPD), 4,4',4"-tris[phenyl(m-tolyl)amino]triphenylamine (m-MTDATA), 4,4' ,4"-tri(N-carbazolyl)-triphenylamine (TCTA), 1,1-bis[(di-4-tolylamino)phenylcyclohexane (TAPC), 4,4',4"-tri(diphenylamino)triphenylamine (TDATA) doped with tetrafluoro-tetracyano-quinodimethane (F4-TCNQ), p-doped phthalocyanine (e.g., F4-TCNQ-doped zinc phthalocyanine (ZnPc)), F4-TCNQ-doped N,N'-diphenyl-N,N'-di(1-naphthyl)-1,1'-biphenyl-4,4"-diamine (α-NPD), hexaazatriphenylene-capronitrile (HAT-CN) or one or more thereof. The fourth material includes but is not limited to at least one of 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene, PEDOT, PEDOT:PSS, PEDOT:PSS doped with s-MoO3 derivatives, 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.

[0048] Accordingly, when preparing the corresponding initial solid film, the solvent used to disperse the film material to form a solution of the film material includes but is not limited to one or more of chlorobenzene, toluene, and xylene.

[0049] In some embodiments, when the material of the initial solid film includes a luminescent material, the initial solid film can be used to make the light-emitting layer 20 of the optoelectronic device 100. The luminescent material is one or more of the organic luminescent materials and quantum dot luminescent materials known in the art. Specifically, the organic luminescent material can be selected from but not limited to 4,4'-bis(N-carbazole)-1,1'-biphenyl:tri[2-(p-tolyl)pyridine iridium(III), 4,4',4"-tri(carbazole-9-yl)triphenylamine:tri[2-(p-tolyl)pyridine iridium, diaromatic anthracene derivatives, distyrene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPX fluorescent materials, TBRb fluorescent materials, DBP fluorescent materials, delayed fluorescent materials, TTA materials, thermally activated delayed materials, polymers containing BN covalent bonds, hybrid localized charge transfer excited state materials, and exciplex luminescent materials.

[0050] The quantum dot luminescent material may be selected from but not limited to at least one of single structure quantum dots, core-shell structure quantum dots and perovskite semiconductor materials; the material of the single structure quantum dots, the core material of the core-shell structure quantum dots and the shell material of the core-shell structure quantum dots are respectively selected from at least one of II-VI group compounds, IV-VI group compounds, III-V group compounds and I-III-VI group compounds; the II-VI group compounds are selected from CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, At least one of 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 compound is selected from SnS, SnSe, SnTe, At least one of PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe; the III-V group compound is selected from GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, Al At least one of NSb, 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 compound is selected from at least one of CuInS2, CuInSe2 and AgInS2.

[0051] As an example, the core-shell structured quantum dots may be selected from but not limited to at least one of CdZnSe / CdZnSe / ZnSe / CdZnS / ZnS, CdZnSe / CdZnSe / CdZnS / ZnSCdSe / 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.

[0052] It should be noted that, for the material of the aforementioned single structure quantum dot, or the material of the core of the core-shell structure quantum dot, or the material of the shell of the core-shell structure quantum dot, the chemical formula provided only indicates the elemental composition, but does 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 indicated, it corresponds to Cd x Zn 1-x Se,0 <x<1。

[0053] The perovskite semiconductor material may be selected from but not limited to doped or undoped inorganic perovskite semiconductors, or organic-inorganic hybrid perovskite semiconductors; the inorganic perovskite semiconductor has a general structural formula of AMX3, wherein 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+ ,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 following; the general structural formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, wherein 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+ 、Cd2+ 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 .

[0054] Correspondingly, when preparing the corresponding initial solid film, the solvent used to disperse the thin film material to form the solution of the thin film material includes but is not limited to one or more of alkane solvents with carbon atoms of 8 to 16 and cycloalkane solvents with carbon atoms of 5 to 16; the alkane solvent with carbon atoms of 8 to 16 is selected from one or more of octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, 2-methyloctane, 3-ethylheptane, 2,2-dimethyloctane, and 1-cyclohexyldecane; the cycloalkane solvent with carbon atoms of 5 to 16 is selected from one or two of cyclooctane, cycloheptane, cyclohexane, and cyclopentane.

[0055] In a second aspect, the present application provides an optoelectronic device 100, which includes but is not limited to an organic light emitting diode, a quantum dot light emitting diode, a photovoltaic cell and a photodetector. Figure 2 The optoelectronic device 100 includes a first electrode, one or more functional layers, and a second electrode, wherein the first electrode is one of a cathode 40 and an anode 10, and the second electrode is the other of the cathode 40 and the anode 10. The one or more functional layers are selected from one or more of an electronic functional layer, a hole functional layer, and a light-emitting layer 20. Among the one or more functional layers, at least one functional layer includes a thin film prepared by the preparation method described above. For example, one or more of the electronic functional layer, the hole functional layer, and the light-emitting layer 20 are processed by the above-mentioned preparation method, and after a solid film is prepared using the corresponding film layer material, a terahertz irradiation treatment is performed.

[0056] Terahertz irradiation of the initial solid film can controllably heat the initial solid film, more effectively remove residual solvents in the initial solid film, prevent residual solvents from affecting the performance stability of the film, and optimize the internal structure and performance of the material. Terahertz irradiation has high frequency selectivity, and can directionally heat specific materials and structures, thereby directionally heating the initial solid film, precisely controlling the heating area, avoiding heating of non-target areas and causing damage to non-target areas, thereby avoiding damage to other film materials when removing solvents from the layer, and helping to improve device life and optoelectronic performance; terahertz irradiation has high spatial resolution and temporal resolution, thereby achieving precise local heating of the target area and precise control of time and temperature during irradiation, helping to further improve film performance, and thus device performance; terahertz radiation The energy is low, and during the heating process, the photothermal damage to the material is small, which can avoid damage to the thin film material, help to enhance the improvement of thin film performance, and also avoid its damage to other film materials of the device, which helps to improve the device life and photoelectric performance; at the same time, terahertz irradiation is non-ionizing radiation, which will not cause ion damage, avoids the impact on the thin film material, helps to improve the thin film performance, and also avoids its damage to other film materials of the device, which helps to improve the device life and photoelectric performance; in addition, terahertz waves have high penetrability, and when used for thin film processing, residual solvents can be removed under low power conditions.

[0057] The anode 10 may be an anode 10 for a photoelectric device 100 known in the art, for example, may be selected from but not limited to 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, and the material of the metal electrode is selected from one or more of Ag, Al, Cu, Mo, Au, Pt, Si, Ca, Mg and Ba.

[0058] The cathode 40 can be a cathode 40 for the optoelectronic device 100 known in the art, for example, can be selected from but not limited to a doped metal oxide particle electrode, a composite electrode of metal and 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 metal and 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, and the material of the metal electrode is selected from one or more of Ag, Al, Cu, Mo, Au, Pt, Si, Ca, Mg and Ba.

[0059] The light-emitting layer 20 may be an organic light-emitting layer or a quantum dot light-emitting layer. When the light-emitting layer 20 is an organic light-emitting layer, the optoelectronic device 100 may be an organic light-emitting device; when the light-emitting layer 20 is a quantum dot light-emitting layer, the optoelectronic device 100 may be a quantum dot light-emitting device. The material of the organic light-emitting layer is an organic light-emitting material known in the art for an organic light-emitting layer of an optoelectronic device 100, and the material of the quantum dot light-emitting layer is a quantum dot light-emitting material known in the art for a quantum dot light-emitting layer of an optoelectronic device 100.

[0060] The hole functional layer includes but is not limited to one or two layers of the hole transport layer 50 and the hole injection layer 60. When the hole functional layer includes the hole transport layer 50 and the hole injection layer 60, the hole transport layer 50 and the hole injection layer 60 are stacked, and the hole injection layer 60 is located between the hole transport layer 50 and the anode 10. The hole functional layer can be prepared using a hole functional material known in the art for the optoelectronic device 100 and having hole transport properties or hole injection properties. Specifically, the material of the hole transport layer 50 can be the third material, and the material of the hole injection layer 60 can be the fourth material.

[0061] The electronic functional layer includes but is not limited to one or two layers of the electron transport layer 30 and the electron injection layer. When the electronic functional layer includes the electron transport layer 30 and the electron injection layer, the electron transport layer 30 and the electron injection layer are stacked, and the electron injection layer is located between the electron transport layer 30 and the cathode 40. The electronic functional layer can be prepared using an electronic functional material known in the art for the optoelectronic device 100, which has electron transport properties or electron injection properties. Specifically, the material of the electron transport layer 30 can be a first material, and the material of the electron injection layer can be a second material.

[0062] The organic light-emitting material, quantum dot light-emitting material, the third material, the fourth material, the first material and the second material have been described in detail in the previous text and will not be repeated here.

[0063] When there are multiple functional layers, and the multiple functional layers are selected from the light-emitting layer 20, the electron transport layer 30, the electron injection layer, the hole transport layer 50, and the hole injection layer 60, the film layer stacking order of the photoelectric device 100 is the anode 10, the hole injection layer 60, the hole transport layer 50, the light-emitting layer 20, the electron transport layer 30, the electron injection layer and the cathode 40; it can be understood that the photoelectric device 100 can be an upright device or an inverted device. In some embodiments, the photoelectric device 100 is an upright device, and accordingly, the photoelectric device 100 includes an anode 10, a hole injection layer 60, a hole transport layer 50, a light-emitting layer 20, an electron transport layer 30, an electron injection layer and a cathode 40 stacked in sequence from bottom to top; in other embodiments, the photoelectric device 100 is an inverted device, and accordingly, the photoelectric device 100 includes a cathode 40, an electron injection layer, an electron transport layer 30, a light-emitting layer 20, a hole transport layer 50, a hole injection layer 60 and an anode 10 stacked in sequence from bottom to top.

[0064] It is understandable that the optoelectronic device 100 may also be provided with some functional layers conventionally used in optoelectronic devices 100 that help improve the performance of the optoelectronic device 100, such as an electron blocking layer, a hole blocking layer, an interface modification layer, etc.

[0065] It can be understood that the materials of each layer of the optoelectronic device 100 can be adjusted according to the actual requirements of the optoelectronic device 100 .

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

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

[0068] In the optoelectronic device 100 provided in the present application, the above-mentioned thin film preparation method is used for one or more functional layers, and conventional preparation methods can also be used for other functional layers, the first electrode and the second electrode. Specifically, the conventional preparation method can be a chemical method or a physical method. Among them, the chemical method includes chemical vapor deposition, continuous ion layer adsorption and reaction method, anodization method, electrolytic deposition method, and coprecipitation method. Physical methods include physical plating methods and solution methods, among which physical plating methods include: thermal evaporation coating method, electron beam evaporation coating method, magnetron sputtering method, multi-arc ion plating method, physical vapor deposition method, atomic layer deposition method, pulsed laser deposition method, etc.; the solution method can be spin coating, printing method, inkjet printing method, scraping method, printing method, dip pulling method, immersion method, spraying method, roll coating method, casting method, slit coating method and strip coating method, etc.

[0069] In some embodiments, after the photoelectric device 100 is prepared, the step of packaging the photoelectric device 100 is further included. The packaging process can be performed by a common machine packaging or by manual packaging. Preferably, in the packaging process environment, the oxygen content and the water content are both less than 0.1 ppm to ensure the stability of the photoelectric device 100.

[0070] In a third aspect, the present application further proposes a display device, comprising the optoelectronic device 100 as described above. The display device can be any electronic product with a display function, including but not limited to smart phones, tablet computers, laptop computers, digital cameras, digital video cameras, smart wearable devices, smart weighing electronic scales, car displays, televisions or e-book readers, wherein the smart wearable device can be, for example, a smart bracelet, a smart watch, a virtual reality (VR) helmet, etc.

[0071] The technical scheme and technical effects of the present application are described in detail below through specific embodiments and comparative examples. The following embodiments are only some embodiments of the present application and do not specifically limit the present application.

[0072] Film Example 1

[0073] (1) Provide a substrate, take a 30 mg / ml ZnO ethanol solution, drop it on the substrate, spin coat it at 3000 rpm for 30 seconds, and then -2 MPa environment for 15 min to obtain an initial ZnO solid film with a thickness of 30 nm.

[0074] (2) The pulse light generated by the femtosecond laser is irradiated on the surface of the initial solid film to generate nonlinear polarization excited terahertz wave radiation (power of 0.1 to 2 THz), and the ZnO is treated for 200 seconds to obtain a thin film.

[0075] Film Example 2

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

[0077] In step (2), the processing time was changed to 150 s.

[0078] Film Example 3

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

[0080] In step (2), the processing time was changed to 300 s.

[0081] Film Example 4

[0082] The scheme of this embodiment is basically the same as that of Embodiment 1, except that in this embodiment:

[0083] In step (2), the processing time was changed to 310 s.

[0084] Film Example 5

[0085] The scheme of this embodiment is basically the same as that of embodiment 1, except that, in this embodiment, steps (1) and (2) are changed to:

[0086] (1) Provide a substrate, take a 15 mg / ml ZnO ethanol solution, drop it on the substrate, spin coat it at 6000 rpm for 30 seconds, and then -2 MPa environment for 15 minutes to obtain a first initial sub-film with a thickness of 15 nm; the pulse light generated by a femtosecond laser is irradiated on the surface of the first initial sub-film to generate nonlinear polarization excited terahertz wave radiation (power is 0.1~2THz), and the ZnO is treated for 100s to obtain the first sub-film.

[0087] (2) Take a 15 mg / ml ZnO ethanol solution, drop it on the first sub-film, spin-coat it at 6000 rpm for 30 seconds, and then -2 MPa environment for 15 minutes to obtain a second initial sub-film with a thickness of 15 nm; the pulse light generated by the femtosecond laser is irradiated on the surface of the second initial sub-film to generate nonlinear polarization excited terahertz wave radiation (power is 0.1~2THz), and the ZnO is treated for 100s to obtain a second sub-film. The first sub-film and the second sub-film together constitute a thin film.

[0088] Film Example 6

[0089] The scheme of this embodiment is basically the same as that of embodiment 5, except that, in this embodiment, after the second sub-film is prepared, the following steps are further included:

[0090] (3) Scan the film obtained in step (2) with an electron beam, setting the electron beam acceleration voltage to 10 3 K, beam energy density 0.825 J / cm 2 , frequency is 1 Hz, scanning time is 10 s, and a thin film is obtained.

[0091] Film Example 7

[0092] The scheme of this embodiment is basically the same as that of embodiment 1, except that, in this embodiment, the initial solid film subjected to annealing is a light-emitting thin film. Accordingly, in this preparation method, step (1) is changed to:

[0093] (1) Take a 20 mg / ml n-hexane solution of CdSe green light quantum dots, drop it on the substrate, spin coat it at 2000 rpm for 30 seconds, and heat it at 100°C for 10 minutes to obtain a CdSe initial solid film with a thickness of 30 nm.

[0094] Film Example 8

[0095] The scheme of this embodiment is basically the same as that of embodiment 1, except that, in this embodiment, the initial solid film subjected to annealing is a hole functional film. Accordingly, in this preparation method, step (1) is changed to:

[0096] A glass substrate was provided, and an ethanol solution of TFB with a concentration of 8 mg / ml was dropped on the surface of the substrate. The solution was spin-coated at a rotation speed of 3000 rpm for 30 seconds and heated at 120° C. for 10 minutes to obtain an initial solid TFB film with a thickness of 40 nm.

[0097] Film Comparative Example 1

[0098] The comparative example is basically the same as Example 1, except that the comparative example is an initial solid ZnO film that has not been irradiated by terahertz radiation. Accordingly, step (2) is omitted in the preparation method.

[0099] Film Comparative Example 2

[0100] The comparative example is basically the same as Example 1, except that in this comparative example, X-ray irradiation is adopted. Accordingly, in step (2), terahertz irradiation is replaced by X-ray irradiation. The irradiation conditions are: tube voltage is 120 kV, tube current is 200 mA, pulse duration is 50 ms, irradiation times are 5 times, and interval time is 2 s.

[0101] Film Comparative Example 3

[0102] The comparative example is basically the same as Example 1, except that, in the comparative example, microwave irradiation is adopted. Accordingly, in step (2), terahertz irradiation is replaced by microwave irradiation, and the power of microwave irradiation is 500W and the time is 30s.

[0103] Film Comparative Example 4

[0104] The comparative example is basically the same as Example 7, except that the comparative example is a CdSe initial solid film that has not been irradiated by terahertz radiation. Accordingly, step (2) is omitted in the preparation method.

[0105] Film Comparative Example 5

[0106] The comparative example is basically the same as Example 8, except that the comparative example is an initial solid TFB film that has not been irradiated by terahertz radiation. Accordingly, step (2) is omitted in the preparation method.

[0107] Device Example 1

[0108] (1) Provide an ITO anode with a thickness of 15 nm, wipe the ITO surface with a cotton swab dipped in a small amount of soapy water to remove impurities visible to the naked eye, then ultrasonically clean it with deionized water, acetone, ethanol, and isopropanol for 15 minutes, and then blow dry it with nitrogen for later use.

[0109] (2) Spin coating PEDOT:PSS material (a commercial product with a doping ratio of 1:6 and a solute content of 1.5 wt%) on the anode at 5000 rpm for 30 seconds, and then heating at 150° C. for 15 minutes to obtain a hole injection layer with a thickness of 30 nm.

[0110] (3) The substrate prepared in step (2) was transferred to a nitrogen atmosphere, and an ethanol solution of 8 mg / ml TFB was dropped on the surface of the hole injection layer. The solution was spin-coated at 3000 rpm for 30 seconds and heated at 120°C for 10 minutes to obtain a hole transport layer with a thickness of 40 nm.

[0111] (4) Take a 20 mg / ml n-hexane solution of CdSe green light quantum dots, drop it on the hole transport layer, spin coat it at 2000 rpm for 30 seconds, and heat it at 100°C for 10 minutes to obtain a light-emitting layer with a thickness of 30 nm.

[0112] (5) Take a 30 mg / ml ZnO ethanol solution, drop it on the light-emitting layer, spin-coat it at 3000 rpm for 30 seconds, and then - 2 MPa environment for 15 min to obtain a solid electron transport layer with a thickness of 30 nm.

[0113] (6) The pulse light generated by the femtosecond laser is irradiated on the surface of the electron transport layer to generate nonlinear polarization excited terahertz wave radiation (power of 0.1 to 2 THz), and the electron transport layer is treated for 200 seconds to obtain a treated electron transport layer.

[0114] (7) Place the sheet prepared in step (6) into a vacuum coating machine and draw the vacuum to 3×10 -4 mbar, turn on the Ag target, the Ag target is The film was evaporated at a rate of 200s to obtain a cathode with a thickness of 20nm, which was then packaged to obtain a QLED device.

[0115] Device Example 2

[0116] The device embodiment scheme is basically the same as device embodiment 1, except that, in the device embodiment:

[0117] In step (6), the processing time was changed to 150 s.

[0118] Device Example 3

[0119] The device embodiment scheme is basically the same as device embodiment 1, except that, in the device embodiment:

[0120] In step (6), the processing time was changed to 300 s.

[0121] Device Example 4

[0122] The device embodiment scheme is basically the same as device embodiment 1, except that, in the device embodiment:

[0123] In step (6), the processing time was changed to 310 s.

[0124] Device Example 5

[0125] The device embodiment scheme is basically the same as device embodiment 1, except that in the device embodiment, steps (5) and (6) are changed to:

[0126] (5) Take a 15 mg / ml ZnO ethanol solution, drop it on the light-emitting layer, spin-coat it at 6000 rpm for 30 seconds, and then - 2 MPa environment for 15 minutes to obtain a first initial sub-film with a thickness of 15 nm; the pulse light generated by a femtosecond laser is irradiated on the surface of the first initial sub-film to generate nonlinear polarization excited terahertz wave radiation (power is 0.1~2THz), and the ZnO is treated for 100s to obtain the first sub-film.

[0127] (6) Take a 15 mg / ml ZnO ethanol solution, drop it on the first sub-film, spin-coat it at 6000 rpm for 30 seconds, and then -2 MPa environment for 15 minutes to obtain a second initial sub-film with a thickness of 15 nm; the pulse light generated by the femtosecond laser is irradiated on the surface of the second initial sub-film to generate nonlinear polarization excited terahertz wave radiation (power is 0.1~2THz), and the ZnO is treated for 100s to obtain the second sub-film. The first sub-film and the second sub-film together constitute the electron transport layer.

[0128] Device Example 6

[0129] The device embodiment scheme is basically the same as the device embodiment 5, except that, in the device embodiment, in step (6), after the second sub-film is prepared, the following steps are further included:

[0130] Use electron beam to scan the first sub-film and the second sub-film, and set the electron beam acceleration voltage to 10 3 K, beam energy density 0.825 J / cm 2 , frequency is 1 Hz, scanning time is 10 s, and a thin film is obtained.

[0131] Device Example 7

[0132] The device embodiment scheme is basically the same as the device embodiment 1, except that, in the device embodiment, the object of the terahertz radiation treatment is the light-emitting layer. Accordingly, in the preparation method, steps (4) to (6) are changed to:

[0133] (4) Take a 20 mg / ml hexane solution of CdSe green light quantum dots, drop it on the hole transport layer, spin coat it at 2000 rpm for 30 s, and then spin coat it for 10 -2 MPa environment for 15 minutes to obtain a solid light-emitting layer with a thickness of 30 nm.

[0134] (5) The pulse light generated by the femtosecond laser is irradiated on the surface of the light-emitting layer to generate nonlinear polarization excited terahertz wave radiation (power of 0.1 to 2 THz), and the light-emitting layer is treated for 200 seconds to obtain a treated light-emitting layer.

[0135] (6) Take a 30 mg / ml ZnO ethanol solution, drop it on the light-emitting layer, spin-coat it at 3000 rpm for 30 seconds, and then - 2 MPa environment for 15 min to obtain an electron transport layer with a thickness of 30 nm.

[0136] Device Example 8

[0137] The device embodiment scheme is basically the same as the device embodiment 1, except that, in the device embodiment, the object of terahertz irradiation treatment is the hole transport layer. Accordingly, in the preparation method, steps (3) to (6) are changed to:

[0138] (3) The substrate prepared in step (2) was transferred to a nitrogen atmosphere, and an 8 mg / ml TFB ethanol solution was dropped onto the surface of the hole injection layer and spin-coated at 3000 rpm for 30 s. -2 MPa environment for 15 min to obtain a solid hole transport layer with a thickness of 40 nm.

[0139] (4) The pulse light generated by the femtosecond laser is irradiated on the surface of the hole transport layer to generate nonlinear polarization excited terahertz wave radiation (power of 0.1 to 2 THz), and the hole transport layer is treated for 200 seconds to obtain a treated hole transport layer.

[0140] (5) Take a 20 mg / ml n-hexane solution of CdSe green light quantum dots, drop it on the hole transport layer, spin coat it at 2000 rpm for 30 seconds, and heat it at 100°C for 10 minutes to obtain a light-emitting layer with a thickness of 30 nm.

[0141] (6) Take a 30 mg / ml ZnO ethanol solution, drop it on the light-emitting layer, spin-coat it at 3000 rpm for 30 seconds, and then - 2 MPa environment for 15 min to obtain an electron transport layer with a thickness of 30 nm.

[0142] Device Example 9

[0143] The device embodiment scheme is basically the same as the device embodiment 1, except that, in the device embodiment, the objects of terahertz irradiation treatment are the hole transport layer and the electron transport layer. Accordingly, in the preparation method, steps (3) to (6) are changed to:

[0144] (3) The substrate prepared in step (2) was transferred to a nitrogen atmosphere, and an 8 mg / ml TFB ethanol solution was dropped onto the surface of the hole injection layer and spin-coated at 3000 rpm for 30 s. -2 MPa environment for 15 min to obtain a solid hole transport layer with a thickness of 40 nm.

[0145] The pulse light generated by the femtosecond laser is irradiated on the surface of the hole transport layer to generate nonlinear polarization excited terahertz wave radiation (power of 0.1-2 THz), and the hole transport layer is treated for 200 seconds to obtain the treated hole transport layer.

[0146] (4) Take a 20 mg / ml n-hexane solution of CdSe green light quantum dots, drop it on the hole transport layer, spin coat it at 2000 rpm for 30 seconds, and heat it at 100°C for 10 minutes to obtain a light-emitting layer with a thickness of 30 nm.

[0147] (5) Take a 30 mg / ml ZnO ethanol solution, drop it on the light-emitting layer, spin-coat it at 3000 rpm for 30 seconds, and then - 2 MPa environment for 15 min to obtain a solid electron transport layer with a thickness of 30 nm.

[0148] (6) The pulse light generated by the femtosecond laser is irradiated on the surface of the electron transport layer to generate nonlinear polarization excited terahertz wave radiation (power of 0.1 to 2 THz), and the electron transport layer is treated for 200 seconds to obtain a treated electron transport layer.

[0149] Device Example 10

[0150] The device embodiment scheme is basically the same as the device embodiment 1, except that, in the device embodiment, the objects of terahertz irradiation treatment are the light-emitting layer, the hole transport layer and the electron transport layer. Accordingly, in the preparation method, steps (3) to (6) are changed to:

[0151] (3) The substrate prepared in step (2) was transferred to a nitrogen atmosphere, and an 8 mg / ml TFB ethanol solution was dropped onto the surface of the hole injection layer and spin-coated at 3000 rpm for 30 s. -2 MPa environment for 15 min to obtain a solid hole transport layer with a thickness of 40 nm.

[0152] The pulse light generated by the femtosecond laser is irradiated on the surface of the hole transport layer to generate nonlinear polarization excited terahertz wave radiation (power of 0.1-2 THz), and the hole transport layer is treated for 200 seconds to obtain the treated hole transport layer.

[0153] (4) Take a 20 mg / ml n-hexane solution of CdSe green light quantum dots, drop it on the hole transport layer, spin coat it at 2000 rpm for 30 seconds, and heat it at 100°C for 10 minutes to obtain a solid light-emitting layer with a thickness of 30 nm.

[0154] The pulse light generated by the femtosecond laser is irradiated on the surface of the light-emitting layer to generate nonlinear polarization excited terahertz wave radiation (power of 0.1-2 THz), and the light-emitting layer is treated for 200 seconds to obtain the treated light-emitting layer.

[0155] (5) Take a 30 mg / ml ZnO ethanol solution, drop it on the light-emitting layer, spin-coat it at 3000 rpm for 30 seconds, and then - 2 MPa environment for 15 min to obtain a solid electron transport layer with a thickness of 30 nm.

[0156] (6) The pulse light generated by the femtosecond laser is irradiated on the surface of the electron transport layer to generate nonlinear polarization excited terahertz wave radiation (power of 0.1 to 2 THz), and the electron transport layer is treated for 200 seconds to obtain a treated electron transport layer.

[0157] Device Comparative Example 1

[0158] The device comparative example scheme is basically the same as the device embodiment 1, except that in the device comparative example, the electron transport layer is a ZnO layer that has not been treated with terahertz radiation, and accordingly, step (6) is omitted.

[0159] Device Comparison Example 2

[0160] The device comparative example is basically the same as the device embodiment 1, except that in the device comparative example, the electron transport layer is a ZnO layer treated by X-ray irradiation. Accordingly, in step (6):

[0161] The terahertz irradiation was changed to X-ray irradiation, and the irradiation conditions were as follows: tube voltage was 120 kV, tube current was 200 mA, pulse duration was 50 ms, irradiation times was 5 times, and interval time was 2 s.

[0162] Device Comparison Example 3

[0163] The device comparative example is basically the same as the device embodiment 1, except that in the device comparative example, the electron transport layer is a ZnO layer irradiated by microwaves. Accordingly, in step (6):

[0164] The terahertz irradiation was changed to microwave irradiation, the power of microwave irradiation was 500w, and the time was 30s.

[0165] Experimental example

[0166] (i) The films prepared in the above-mentioned film examples 1-8 and film comparison examples 1-5 were taken and their properties were tested. The results are shown in Table 1.

[0167] The detection method is as follows: prepare a detection device with a device structure of anode / film / cathode, power the device with a constant current of 2MA, and record the time taken for the voltage fluctuation to exceed 95% as the voltage stabilization time.

[0168] The steps of preparing the device are as follows: providing an ITO anode, cleaning and drying it. Referring to the methods of thin film examples 1-8 and thin film comparison examples 1-5, a corresponding thin film is prepared on the anode. Finally, a 20 nm thick Ag layer is evaporated on the thin film as a cathode.

[0169] Table 1

[0170]

[0171]

[0172] Refer to Table 1, we can see that:

[0173] Comparison of film comparative example 1 with film examples 1-6, comparison of film comparative example 4 with film example 7, and comparison of film comparative example 5 with film example 7 show that in each comparison, each example has a higher voltage stabilization time, indicating that the films of each example have higher stability than the comparative examples, indicating that the removal of residual solvent by terahertz irradiation is helpful to improve the stability of the film;

[0174] Furthermore, by comparing the film example 1, the film comparison examples 2 and 3 with the film comparison example 1, it can be seen that although the voltage stabilization time of the film example 1, the film comparison examples 2 and 3 are all higher than that of the film comparison example 1, the increase in the increase in the film example 1 is more significant, indicating that compared with microwaves and X-rays, the use of terahertz waves to irradiate the film has a better effect on improving the stability of the film. This may be because microwaves are prone to cause ion damage, and the thermal effect of X-rays is relatively higher, and the two have a greater adverse effect on the film material;

[0175] In addition, by comparing thin film example 1, thin film example 5 and thin film example 6, it can be seen that by splitting the initial solid film into multiple sub-films and subjecting them to terahertz irradiation respectively, it helps to further improve the stability of the film. By further electron beam scanning the irradiated film, it helps to repair defects in the film and further improve the stability of the film.

[0176] (II) The devices prepared in the above device embodiments 1-10 and device comparative examples 1-3 were tested for performance. The results are recorded in Table 2. The test method is as follows:

[0177] (1) The optical property measurement equipment of FPD (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 connecting wires and data cards, efficiency test cassettes and data acquisition systems) was used to detect the parameters of each optoelectronic device, such as the start-up voltage, current, brightness (L), and luminescence spectrum. 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 life test equipment.

[0178] (2) The current efficiency test method is: set the luminous area to 2mm×2mm=4mm 2 , intermittently collect the brightness value of the photoelectric device in the range of 0V to 8V driving voltage. The initial voltage value of the brightness is 3V. The data is collected every 0.2V. Each collected brightness value is divided by the corresponding current density to obtain the current efficiency of the photoelectric device under the collection conditions, and the maximum current efficiency (C.Emax, cd / A) is obtained.

[0179] (3) The test method for service life is as follows: under the drive of constant current (2mA), a 128-channel QLED life test system is used to analyze the electroluminescent life of each optoelectronic device, and the time required for each optoelectronic device to decay from the maximum brightness to 95% (T95, h) is recorded. The time required for the brightness of each optoelectronic device to decay from 100% to 95% at a brightness of 1000nit is calculated by the decay fitting formula (T95@1000nit, h).

[0180] Table 2

[0181]

[0182]

[0183] Refer to Table 2, we can see that:

[0184] The device embodiments have a higher lifespan than the device comparison examples, and the lifespan improvement of device embodiment 6 is the highest, indicating that terahertz irradiation treatment of the functional layers of the device, such as the electron transport layer, the hole transport layer, the light-emitting layer, etc., can help extend the service life of the device; after irradiation, further electron beam scanning of the film layer can also help repair defects in the film, further extending the service life of the device.

[0185] The above is a detailed introduction to the thin film preparation method, optoelectronic device and display device provided in the embodiments of the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea; at the same time, for technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A method for preparing a thin film, characterized in that: The following steps are involved: providing an initial solid film; The initial solid film is subjected to terahertz irradiation to obtain a thin film.

2. The preparation method according to claim 1, characterized in that: The frequency of the terahertz radiation is 0.1 to 10 THz; and / or, The terahertz irradiation time is 50 to 2000 seconds; and / or, The thickness of the initial solid film is 30-80 nm.

3. The preparation method according to claim 1, characterized in that: The initial solid film includes a plurality of initial sub-films; The step of subjecting the initial solid film to terahertz radiation to obtain a thin film comprises: The plurality of initial sub-films are respectively subjected to terahertz irradiation to obtain a plurality of sub-films, and the plurality of sub-films constitute the thin film.

4. The preparation method according to claim 3, characterized in that: When each of the initial sub-films is subjected to terahertz irradiation, the frequency of the terahertz irradiation is 0.1 to 10 THz; and / or, When each of the initial sub-films is subjected to terahertz irradiation, the terahertz irradiation time is 50 to 200 seconds; and / or, The thickness of the initial sub-film is 3 to 40 nm; and / or, The initial solid film includes 2 to 10 initial sub-films.

5. The preparation method according to claim 1, characterized in that: After the step of subjecting the initial solid film to terahertz irradiation, and before the step of obtaining the thin film, the method further comprises: The initial solid film irradiated by the terahertz radiation is scanned by an electron beam.

6. The preparation method according to claim 5, characterized in that: The scanning time is 5 to 60 seconds; and / or, The accelerating voltage of the electron beam is 1×10 3 ~8×10 3 K; and / or, The electron beam energy density is 0.5-2 J / cm 2 and / or, The frequency of the electron beam is 0.5-2 Hz.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The material of the initial solid film includes a first material, and the first 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 oxide includes one or more of ZnO, TiO2, and SnO2; the metal oxide in the doped metal oxide includes one or more of ZnO, TiO2, and SnO2, and the doping element includes one or more of Al, Mg, Li, In, and Ga; the IIB-VIA group material includes one or more of ZnS, ZnSe, CdS, and CdSe; the IIIB-VA group material includes one or more of InP and GaP; the IB-IIIB-VIA group material includes one or more of CuInS and CuGaS; or, The material of the initial solid film includes a second material, and the second material includes at least one of cesium carbonate, cesium fluoride, cesium azide and lithium fluoride; or, The material of the initial solid film includes a luminescent material, and the luminescent material includes one or more of an organic luminescent material and a quantum dot luminescent material. The organic luminescent material includes 4,4'-bis(N-carbazole)-1,1'-biphenyl:tri[2-(p-tolyl)pyridine iridium(III), 4,4',4"-tri(carbazole-9-yl)triphenylamine:tri[2-(p-tolyl)pyridine iridium, diaromatic anthracene derivatives, distilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPX fluorescent materials, TBRb fluorescent materials, DBP fluorescent materials. The invention relates to a material, a delayed fluorescence material, a TTA material, a thermally activated delayed material, a polymer containing a covalent bond of BN, a hybrid localized charge transfer excited state material, and an exciplex luminescent material, wherein the quantum dot luminescent material comprises 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 comprise at least one of a II-VI group compound, an IV-VI group compound, a III-V group compound, and an I-III-VI group compound. At least one; the II-VI group compound includes 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, CdZnSeT e, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe and HgZnSTe; the IV-VI group compound includes 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 compounds include GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, and AlN P, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInN P, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs and InAlPSb; the I-III-VI group compound includes at least one of CuInS2, CuInSe2 and AgInS2; the perovskite semiconductor material includes a doped or undoped inorganic perovskite semiconductor, or an organic-inorganic hybrid perovskite semiconductor; the inorganic perovskite semiconductor has a general structural formula of AMX3, wherein 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+ ,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 following; the general structural formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, wherein 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; or, The material of the initial solid film includes a third material, and the third material includes 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, tris(3-methylphenylphenylamino)-triphenylamine, poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))] and poly(4-butylphenyl- one or more of diphenylamine), polyaniline, polypyrrole, 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, aromatic tertiary amine, polynuclear aromatic tertiary amine, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compound, 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'-di(naphthalene-1-yl)-N,N'-diphenylbenzidine, and spiro NPB; or, The material of the initial solid-state film includes a fourth material, and the fourth material includes at least one of 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.

8. A photoelectric device, characterized in that: It comprises a first electrode, one or more functional layers and a second electrode, wherein at least one of the one or more functional layers comprises a thin film obtained by the preparation method according to any one of claims 1 to 7.

9. The optoelectronic device according to claim 8, characterized in that: The first electrode is selected from a doped metal oxide particle electrode, a composite electrode of metal and 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 metal and 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 metal and 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 metal and 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 transport layer, a hole injection layer, an electron transport layer and an electron injection layer, wherein the material of the light-emitting layer includes the light-emitting material, the material of the electron transport layer includes the first material, the material of the electron injection layer includes the second material, the material of the hole transport layer includes the third material, and the material of the hole injection layer includes the fourth material; at least one of the light-emitting layer, the hole transport layer, the hole injection layer, the electron transport layer and the electron injection layer is prepared by the preparation method according to any one of claims 1 to 7.

10. A display device, characterized in that: Comprising the optoelectronic device according to claim 8 or 9.

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