Thin film and preparation method therefor, and photoelectric device

Abstract

A thin film and a preparation method therefor, and a photoelectric device. The method comprises: providing a mixed solution, the mixed solution comprising a hole functional material and an additive; and performing deposition on the mixed solution, and then performing annealing to remove the additive, so as to obtain the thin film. The problem of low hole mobility of existing thin films made of hole functional materials is solved.

Description

Thin film, preparation method thereof, and photoelectric device

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on June 16, 2023, with application number 202310724008.1 and application name “Thin film and its preparation method, optoelectronic device and display device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of semiconductors, and in particular to a thin film, a preparation method thereof, and a photoelectric device. Background Art

[0003] Some organic materials, such as polystyrene sulfonate (PEDOT:PSS) and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4′-(N-(4-sec-butylphenyl)diphenylamine)] (TFB), typically exhibit hole injection and hole transport properties, making them suitable for the preparation of hole-functional films. However, films made from these materials typically have low hole mobility, making them unsuitable for applications requiring high hole injection and transport performance. Technical Solutions

[0004] Therefore, the present application provides a thin film, a preparation method thereof, and a photoelectric device.

[0005] In a first aspect, the present application provides a method for preparing a thin film, comprising the following steps:

[0006] Providing a mixed solution, wherein the mixed solution includes a hole functional material and an additive;

[0007] depositing the mixed solution, and then annealing to remove the additive to obtain a thin film;

[0008] Wherein, the additive includes a compound having a structure shown in formula (1):

[0009] wherein Ring A comprises one or more of an aromatic ring having 6 to 40 ring carbon atoms and a heteroaromatic ring having 6 to 40 ring atoms, and n is a positive integer;

[0010] Each occurrence of X is independently selected from one or more of hydrogen, deuterium, and an electron donating group.

[0011] Optionally, in some embodiments of the present application, the electron-donating group includes -NH2, A combination of one or more of C1-C3 alkyl and C1-C3 alkoxy.

[0012] Optionally, in some embodiments of the present application, ring A includes one or more of an aromatic ring having 6 to 20 ring carbon atoms and a heteroaromatic ring having 6 to 20 ring atoms.

[0013] Optionally, in some embodiments of the present application, ring A is selected from one or more rings of any one of the structures shown in formulae (2) to (7):

[0014] Optionally, in some embodiments of the present application, n is 1-4.

[0015] Optionally, in some embodiments of the present application, n is 1 or 2.

[0016] Optionally, in some embodiments of the present application, the boiling point of the additive is greater than or equal to 100°C and less than 200°C.

[0017] Optionally, in some embodiments of the present application, the additive includes one or more compounds having a structure represented by any one of the following formulae (8) to (16):

[0018] Optionally, in some embodiments of the present application, each occurrence of X is independently selected from the electron-donating group.

[0019] Optionally, in some embodiments of the present application, the additive includes one or more compounds having a structure represented by any one of formulas (11) to (16):

[0020] Optionally, in some embodiments of the present application, the mass of the additive accounts for 5-10% of the total mass of the additive and the hole functional material.

[0021] Optionally, in some embodiments of the present application, the hole functional material includes a hole transport material or a hole injection material, and the hole transport material is selected from poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], poly(4-butylphenyl-diphenylamine), poly(triarylamine), polypyrrole, poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine], poly(p-phenylene vinylene), poly[2-methoxy- At least one of poly[5-(2-ethylhexyloxy)-1,4-phenylene vinylene] and poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene], PEDOT:PSS and derivatives thereof, poly(N-vinylcarbazole) and derivatives thereof, polymethacrylate and derivatives thereof, poly(9,9-octylfluorene) and derivatives thereof, poly(spirofluorene) and derivatives thereof; the hole injection material is selected from at least one of PEDOT, PEDOT:PSS and copper phthalocyanine.

[0022] Optionally, in some embodiments of the present application, in the step of depositing the mixed solution and then annealing to remove the additive to obtain a thin film, the annealing temperature is 200-230°C.

[0023] Optionally, in some embodiments of the present application, the annealing time is 15 to 45 minutes.

[0024] Optionally, in some embodiments of the present application, the mixed solution further includes a solvent, and the solvent includes one or more of an alcohol solvent, chloroform, chlorobenzene, and dichlorobenzene.

[0025] Optionally, in some embodiments of the present application, the concentration of the hole functional material in the mixed solution is 2 to 15 mg / ml.

[0026] In a second aspect, the present application proposes a thin film, wherein the material of the thin film includes a hole functional material, and the root mean square roughness of the thin film is 0.3 to 1.5.

[0027] Optionally, in some embodiments of the present application, the hole mobility of the film is 10 -3 ~10 -1 cm 2 V –1 s –1 .

[0028] In a third aspect, the present application proposes a photoelectric device comprising a first electrode, a hole functional layer and a second electrode, wherein the hole functional layer comprises one or two layers of a hole injection layer and a hole transport layer, and at least one layer of the hole functional layer comprises the thin film as described above, or comprises a thin film prepared by the preparation method described above.

[0029] Optionally, in some embodiments of the present application, the first electrode and the second electrode are each independently 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, 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.

[0030] Optionally, in some embodiments of the present application, the optoelectronic device further comprises a light-emitting layer, the light-emitting layer being provided between the first electrode and the hole-functional layer, or the light-emitting layer being provided between the second electrode and the hole-functional layer, the material of the light-emitting layer being selected from one or more of an organic light-emitting material and a quantum dot light-emitting material, the organic light-emitting material being selected from 4,4'-bis(N-carbazole)-1,1'-biphenyl:tris[2-(p-tolyl)pyridineiridium(III), 4,4',4"-tris(carbazole-9-yl)triphenylamine:tris[2-(p-tolyl) One or more of iridium pyridine, diarylanthracene derivatives, distyrene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPX fluorescent materials, TBRb fluorescent materials, DBP fluorescent materials, delayed fluorescence materials, TTA materials, thermally activated delayed materials, polymers containing BN covalent bonds, hybrid localized charge transfer excited state materials, and exciplex luminescent materials; the quantum dot luminescent material is selected from 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, core-shell structure quantum dots, and perovskite semiconductor materials The core material of the structured quantum dots and the shell material of the core-shell structured quantum dots are respectively selected from at least one of II-VI compounds, IV-VI compounds, III-V compounds and I-III-VI compounds; the II-VI compounds are selected from CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, Cd At least one of ZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe and HgZnSTe; the IV-VI group compound is 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 compound is selected from the group consisting of 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, at least one of GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNPs, InAlNAs, InAlNSb, InAlPAs and InAlPSb; the I-III-VI group compound is selected from at least one of CuInS2, CuInSe2 and AgInS2; the perovskite semiconductor material is selected from 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+ 、Cd 2+ Cr 2+ 、Mn 2+ 、Co 2+ 、Fe 2+ 、Ge 2+ 、Yb 2+ 、Eu2+ At least one of, X is a halogen anion selected from Cl - Br - , I - At least one of . BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. 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.

[0032] FIG1 is a schematic flow chart of a method for preparing a thin film according to an embodiment of the present application;

[0033] FIG2 is a schematic structural diagram of a photoelectric device proposed in one embodiment of the present application;

[0034] FIG3 is a schematic structural diagram of a photoelectric device proposed in another embodiment of the present application;

[0035] FIG4 is an AFM image of the control group in Experimental Example 1;

[0036] FIG5 is an AFM image of the experimental group in Experimental Example 1;

[0037] Reference numerals:

[0038] 100 - photoelectric device; 10 - anode; 20 - light-emitting layer; 30 - electron transport layer; 40 - cathode; 50 - hole transport layer; 60 - hole injection layer.

[0039] Implementation Methods of the Application

[0040] The following will clearly and completely describe the technical solutions in the embodiments of the present application 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, not 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 are within 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. In the present application, unless otherwise specified, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the specification of the present application, the term "including" means "including but not limited to". The various embodiments of the present application may be 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 understood as a rigid limitation on the scope of the present application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, description of a range from 1 to 6 should be considered to have specifically disclosed subranges 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 individual numbers within that range, such as 1, 2, 3, 4, 5, and 6. Furthermore, whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range.

[0041] In this application, "and / or" describes the association relationship between associated objects, indicating that three relationships can exist. 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.

[0042] In this 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, and c can be single or multiple.

[0043] In this application, "annulation" refers to the situation in which two rings in a compound share two directly connected carbon atoms and are bonded to each other, wherein the two shared carbon atoms are called common carbon atoms, and the total number of atoms belonging to the common carbon atoms in the compound is the number of common carbon atoms; for example, naphthalene is an annulation of two benzene rings, and its number of common carbon atoms is 2.

[0044] In the present application, the "number of ring atoms" refers to the number of atoms among the atoms constituting the ring itself of a structural compound (e.g., a monocyclic compound, a condensed ring compound, a cross-linked compound, a carbocyclic compound, a heterocyclic compound) in which atoms are bonded to form a ring. When the ring is substituted by a substituent, the atoms contained in the substituent are not included in the ring atoms. The same also applies to the "number of ring atoms" described below unless otherwise specified. For example, the number of ring atoms of a benzene ring is 6, the number of ring atoms of a naphthalene ring is 10, and the number of ring atoms of a thienyl group is 5. The "number of ring carbon atoms" refers to the number of atoms among the carbon atoms constituting the ring itself. For example, the number of ring carbon atoms of a benzene ring is 6, and the number of ring carbon atoms of a thienyl group is 4.

[0045] In this application, "aromatic ring or aromatic ring" refers to a cyclic compound containing a benzene ring, which can be a single ring or a condensed ring formed by multiple rings. For polycyclic rings, at least one is an aromatic ring system. For example, "aromatic ring having 6 to 40 ring atoms" refers to an aromatic ring containing 6 to 40 ring atoms, preferably an aromatic ring having 6 to 30 ring atoms, more preferably an aromatic ring having 6 to 18 ring atoms, and particularly preferably an aromatic ring having 6 to 14 ring atoms; suitable examples include, but are not limited to, benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, tetracene ring, fluorene ring, indene ring, etc.

[0046] In the present application, "heteroaromatic ring" means that at least one carbon atom in the aromatic ring is replaced by a non-carbon atom, and the non-carbon atom can be an N atom, an O atom, an S atom, etc. Suitable examples include, but are not limited to, thiophene, furan, pyrrole, imidazole, diazole, triazole, pyridine, bipyridine, pyrimidine, triazine, acridine, pyridazine, pyrazine, quinoline, isoquinoline, quinazoline, quinoxaline, phthalazine, pyridopyrimidine, pyridopyrazine, benzothiophene, benzofuran, indole, pyrroloimidazole, pyrrolopyrrole, thienopyrrole, thienothiophene, furopyrrole, furofuran, thienofuran, benzisoxazole, benzisothiazole, benzimidazole, o-naphthyridine, phenanthridine, primary idine, quinazolinone, dibenzothiophene, dibenzofuran, carbazole and derivatives thereof.

[0047] In this application, "alkyl" can refer to a straight-chain alkyl or a branched-chain alkyl. "C1-3 alkyl" refers to an alkyl group containing 1 to 3 carbon atoms, and each occurrence can independently be a C1 alkyl, a C2 alkyl, or a C3 alkyl. Non-limiting examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, and the like.

[0048] In the present application, an alkoxy group has a structural feature of the formula -OR, wherein R refers to an alkyl group.

[0049] In this application, -(X) nIt means that there are n substitutable sites on the main structure ring connected to a substituent X, that is, n Xs are connected one by one to any substitutable site on the ring, and the X connected to each site can independently select the type of group, and the n Xs can be the same or different.

[0050] In a first aspect, the present application provides a method for preparing a thin film, which can be used to prepare a P-type semiconductor thin film, such as the hole transport layer 50 and / or the hole injection layer 60 of the optoelectronic device 100. Referring to FIG. 1 , the thin film preparation method includes the following steps:

[0051] S10, providing a mixed solution, wherein the mixed solution includes a hole functional material and an additive;

[0052] S20, depositing the mixed solution, and then annealing to remove the additive to obtain a thin film;

[0053] Wherein, the additive includes a compound having a structure shown in formula (1):

[0054] wherein Ring A comprises one or more of an aromatic ring having 6 to 40 ring carbon atoms and a heteroaromatic ring having 6 to 40 ring atoms, and n is a positive integer;

[0055] Each occurrence of X is independently selected from one or more of hydrogen, deuterium, and an electron donating group.

[0056] In the present application, specific additives are added when depositing thin film materials. The additives can form intermolecular π-π interactions with the hole functional material or induce local crystallization of the hole functional material. In this way, when the thin film is made, the morphological regularity of the thin film is improved, the film morphology is improved, the intermolecular aggregation behavior is enhanced, the crystallinity is enhanced, and the hole injection and transmission capabilities are improved.

[0057] In some embodiments, Ring A comprises one or more of an aromatic ring having 6 to 20 ring carbon atoms and a heteroaromatic ring having 6 to 20 ring atoms; in other embodiments, Ring A is selected from one or more of the rings of any one of the structures shown in Formulas (2) to (7):

[0058] In some embodiments, n is 1 to 4, for example, 1, 2, 3 or 4; in other embodiments, n is 1 or 2, which helps to fully exert the intermolecular force and improve the steric effect.

[0059] In some embodiments, the boiling point of the additive is lower than the annealing temperature. For example, the boiling point of the additive is greater than or equal to 100°C and less than 200°C. For example, the boiling point can be 200°C to 190°C, 190°C to 150°C, 160°C to 130°C, 140°C to 110°C, 120°C to 100°C, and so on. Since the annealing temperature of most hole-functional materials is between 200°C and 230°C, when the mixed solution is deposited and annealed, the additive will also be removed during the thermal annealing process. This allows the film to retain the regular morphology induced by the additive, improving its performance, while avoiding additive residue and preventing the additive from affecting the film. Moreover, since there is no need to worry about the possible impact caused by additive residue, the types of additive materials available are expanded, reducing the difficulty of material development.

[0060] In some embodiments, the mass of the additive accounts for 5% to 10% of the total mass of the additive and the hole functional material; for example, it can be 5%, 6%, 7%, 8%, 9%, 10% and a value between any two values ​​listed above. Within this range, it can effectively improve the stability and electrical properties of the semiconductor material and ensure that the material has good film-forming properties.

[0061] In some specific embodiments, the additives include terthiophene (CAS: 3593-75-7; boiling point 138°C; structural formula as shown in formula (8)), indene (CAS: 95-13-6; boiling point 182°C; structural formula as shown in formula (9)), benzofuran (CAS: 271-89-6; boiling point 173°C; structural formula as shown in formula (10)), 1-methoxynaphthalene (CAS: 2216-69-5; boiling point 135°C; structural formula as shown in formula (11)), p-methoxyacetophenone (CAS: 100-06-1; boiling point 152℃; structural formula as shown in formula (12)), aniline (CAS: 62-53-3; boiling point 184℃; structural formula as shown in formula (13)), N,N-dimethyl-1-phenylethylamine (CAS: 2449-49-2; boiling point 189℃; structural formula as shown in formula (14)), 1-methylindane (CAS: 27133-93-3; boiling point 193℃; structural formula as shown in formula (15)), 2-methylindane (CAS: 824-63-5; boiling point 195℃; structural formula as shown in formula (16)). These additives have strong interactions with P-type semiconductor materials and have relatively low boiling points, making them easy to remove. Specifically, the structural formulas of the above compounds are shown in the following formulas (8) to (16) in sequence.

[0062] In some embodiments, each occurrence of X is independently selected from the electron donating groups described herein, including -NH2 (amino), A combination of one or more of a (keto) group, a C1-C3 alkyl group, and a C1-C3 alkoxy group helps enhance the interaction between the additive and the hole-functional material, thereby enhancing the effect. Accordingly, the additive includes one or more of 1-methoxynaphthalene, p-methoxyacetophenone, aniline, N,N-dimethyl-1-phenylethylamine, 1-methylindane, and 2-methylindane.

[0063] In some embodiments, the hole functional material can be selected from the organic materials commonly used in the art for preparing the hole transport layer 50 or the hole injection layer 60. When selected from the organic material used to prepare the hole transport layer 50, the hole functional material is defined as a hole transport material; when selected from the organic material used to prepare the hole injection layer 60, the hole functional material is defined as a hole injection material.

[0064] In one embodiment, the hole functional material is selected from hole transport materials, such as but not limited to poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))] (TFB), At least one of poly(4-butylphenyl-diphenylamine), poly(triarylamine) (PTAA), polypyrrole, poly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)-benzidine] (polyTPD), poly(p-)phenylenevinylene (PPV), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] and poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene], 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; in actual application, the film obtained by using the hole functional materials listed above can be used as the hole transport layer 50 of the optoelectronic device 100.

[0065] In another embodiment, the hole functional material is selected from hole injection materials, such as but not limited to at least one of PEDOT, PEDOT:PSS, and copper phthalocyanine; in actual application, the film obtained using the hole functional materials listed above can be used as the hole injection layer 60 for preparing the optoelectronic device 100.

[0066] In some embodiments, the mixed solution may further include a solvent for dispersing the hole-functional material and the additive. The solvent may be any common solvent capable of dissolving the hole-functional material and the additive, for example, one or more of an alcohol solvent, chloroform, chlorobenzene, and dichlorobenzene. The alcohol solvent includes, but is not limited to, one or more of methanol, ethanol, isopropanol, n-propanol, n-butanol, and pentanol.

[0067] In some embodiments, in the mixed solution, the concentration of the hole functional material is 2 to 15 mg / ml, for example, it can be 2 mg / ml, 3 mg / ml, 4 mg / ml, 5 mg / ml, 8 mg / ml, 10 mg / ml, 12 mg / ml, 15 mg / ml and values ​​between any two of the above values.

[0068] In some embodiments, in step S20, the annealing method can be heat treatment annealing. Specifically, the annealing temperature can be 200-230°C, for example, 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C and values ​​between any two of the above values.

[0069] The annealing time may be 15 to 45 min, for example, 15 min, 20 min, 25 min, 27 min, 28 min, 29 min, 30 min, 31 min, 32 min, 33 min, 35 min, 40 min, 45 min, or a value between any two of the above values.

[0070] In a second aspect, the present application proposes a thin film, the material of which includes a hole functional material, and the root mean square roughness of the thin film is 0.3 to 1.5, for example, it can be 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5 and values ​​between any two of the above values.

[0071] The film has better morphology regularity and better hole injection and hole transport capabilities.

[0072] In some embodiments, the hole mobility of the film is 10 -3 ~10 -1 cm 2 V –1 s –1 For example, it can be 1×10 -3 cm 2 V –1 s –1 , 2×10 -3 cm 2 V –1 s –1 , 3×10 -3 cm 2 V –1 s –1 , 4×10 -3 cm 2 V –1 s –1 , 5×10 -3 cm2 V –1 s –1 , 6×10 -3 cm 2 V –1 s –1 , 7×10 -3 cm 2 V –1 s –1 , 8×10 -3 cm 2 V –1 s –1 , 9×10 -3 cm 2 V –1 s –1 , 1×10 -2 cm 2 V –1 s –1 , 2×10 -2 cm 2 V –1 s –1 , 3×10 -2 cm 2 V –1 s –1 , 4×10 -2 cm 2 V –1 s –1 , 5×10 -2 cm 2 V –1 s –1 , 6×10 -2 cm 2 V –1 s –1 , 7×10 -2 cm 2 V –1 s –1 , 8×10 -2 cm 2 V –1 s –1 , 9×10 -2 cm 2 V –1 s –1 , 1×10 -1 cm 2 V –1 s –1 and values ​​between any two of the above values.

[0073] The hole functional material can be selected from organic materials commonly used in the art for preparing the hole transport layer 50 or the hole injection layer 60 . The materials are as described above and will not be described in detail here.

[0074] In some embodiments, the thin film can be prepared by the above-described preparation method. Depending on the type of hole-functional material in the mixed solution, the properties of the thin film vary accordingly. For example, in some embodiments, when the hole-functional material is the hole transport material, the thin film can be a hole transport thin film; in other embodiments, when the hole-functional material is the hole injection material, the thin film can also be a hole injection thin film.

[0075] In a third aspect, the present application also proposes a photoelectric device 100, which includes but is not limited to a light-emitting device, a photovoltaic cell, and a photodetector. The photoelectric device 100 includes a first electrode, a hole-functional layer, and a second electrode. The first electrode is one of the cathode 40 and the anode 10, and the second electrode is the other of the cathode 40 and the anode 10. Referring to FIG2 , the photoelectric device 100 includes a first electrode, a hole-functional layer, and a second electrode. The hole-functional layer includes one or two layers of a hole injection layer 60 and a hole transport layer 50, and the material of at least one layer of the hole-functional layer includes the thin film described above. One or both layers of the hole injection layer 60 and the hole transport layer 50 are the thin films described above, that is, one or both layers are induced and adjusted by the additive during preparation, and have better morphology, higher hole injection and transport properties, thereby helping to improve the carrier balance of the device and thereby enhance the performance of the device.

[0076] It can be understood that when the hole transport layer 50 adopts the film as described above, in the process of preparing the film, the hole functional material in the mixed solution used is selected from poly [(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], poly (4-butylphenyl-diphenylamine), poly (triarylamine), polypyrrole, poly [N, N'-bis (4-butylphenyl) -N, N'-bis (phenyl) - benzidine], poly (p) phenylene vinylene, poly [2-methoxy-5- (2-ethylhexyloxy) -1,4-phenylene vinylene] and poly [2-methoxy-5- (3',7'-dimethyloctyloxy) -1,4-phenylene vinylene], PEDOT:PSS and its derivatives, poly (N-vinyl carbazole) and its derivatives, poly methacrylate and its derivatives, poly (9,9-octylfluorene) and its derivatives, At least one of poly (spirofluorene) and its derivatives; when the hole injection layer 60 adopts the film as described above, in the process of preparing the film, the hole functional material in the mixed solution used is selected from at least one of PEDOT, PEDOT:PSS, and copper phthalocyanine.

[0077] In some embodiments, the hole functional layer includes the stacked hole injection layer 60 and the hole transport layer 50, wherein the hole transport layer 50 and the hole injection layer 60 are both prepared using the above-mentioned thin film preparation method. Accordingly, the hole functional material of the hole injection layer 60 is selected from the above-mentioned hole injection materials, and the hole functional material of the hole transport layer 50 is selected from the above-mentioned hole transport materials. For example, the material of the hole transport layer 50 is poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))] and a first additive; the material of the hole injection layer 60 is PEDOT:PSS and a second additive. It can be understood that the first additive and the second additive are both the additives described above, and are named only to distinguish each other. The two can be the same or different.

[0078] In other embodiments, the hole functional layer includes the stacked hole injection layer 60 and the hole transport layer 50, wherein the hole transport layer 50 is prepared by the above-mentioned thin film preparation method, and the hole injection layer 60 can be realized by conventional techniques in the art. In some other embodiments, the hole functional layer includes the stacked hole injection layer 60 and the hole transport layer 50, wherein the hole injection layer 60 is prepared by the above-mentioned thin film preparation method, and the hole transport layer 50 can be realized by conventional techniques in the art. The conventional techniques in the art include but are not limited to chemical methods or physical methods. Among them, chemical methods include chemical vapor deposition, continuous ion layer adsorption and reaction method, anode 10 oxidation method, electrolytic deposition method, and coprecipitation method. Physical methods include physical coating methods and solution methods. Among them, physical coating 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.; solution methods can be spin coating method, printing method, inkjet printing method, doctor blade method, printing method, dip pulling method, immersion method, spraying method, roll coating method, casting method, slit coating method and strip coating method, etc.

[0079] When conventional techniques are used to prepare the hole transport layer 50 or the hole injection layer 60, the materials for each are also commonly used in the art. For example, the material for the hole injection layer 60 can be selected from materials conventionally used in the art for preparing the hole injection layer 60, such as, but not limited to, 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, and copper phthalocyanine. The material of the hole transport layer 50 is selected from the conventional materials used in the art for preparing the hole transport layer 50, for example, it can be selected from but not limited to 4,4'-N,N'-dicarbazolyl-biphenyl, N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4"-diamine, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine, N,N'-bis(3-methylphenyl)- -N,N'-bis(phenyl)-spiro, N,N'-bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine, 4,4',4'-tri(N-carbazolyl)-triphenylamine, 4,4',4'-tri(N-3-methylphenyl-N-phenylamino)triphenylamine, poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], poly(4-butylphenyl) -diphenylamine), poly(triarylamine), polypyrrole, poly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)-benzidine], poly(p-)phenylenevinylene, poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] and poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene], copper phthalocyanine, aromatic tertiary amine, polynuclear aromatic tertiary amine, 4,4′-bis( At least one of (4-carbazolyl)-1,1'-biphenyl compounds, N,N,N',N'-tetraarylbenzidine, PEDOT:PSS and its derivatives, poly(N-vinylcarbazole) and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, N,N'-di(naphthalene-1-yl)-N,N'-diphenylbenzidine, spiro NPB, doped graphene, undoped graphene, and C60.

[0080] In some embodiments, the anode 10 can be an anode 10 known in the art for a photoelectric device 100, for example, it 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.

[0081] In some embodiments, the cathode 40 can be a cathode 40 known in the art for the optoelectronic device 100, for example, it 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.

[0082] Referring to FIG. 3 , in some embodiments, the optoelectronic device 100 further includes a light-emitting layer 20 disposed between the first electrode and the hole-functional layer. Specifically, the light-emitting layer 20 is located between the cathode 40 and the hole-functional layer. 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.

[0083] The material of the organic light-emitting layer is a material known in the art for the organic light-emitting layer of the optoelectronic device 100, for example, it can be selected from but not limited to 4,4'-bis(N-carbazole)-1,1'-biphenyl:tris[2-(p-tolyl)pyridine iridium(III), 4,4',4"-tris(carbazole-9-yl)triphenylamine:tris[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 delay materials, polymers containing BN covalent bonds, hybrid localized charge transfer excited state materials, and exciplex light-emitting materials. One or more of these.

[0084] The material of the quantum dot light-emitting layer is a quantum dot material known in the art for the quantum dot light-emitting layer of the optoelectronic device 100, for example, can be selected from but not limited to at least one of single structure quantum dots, core-shell structure quantum dots and perovskite type 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 compound is selected from 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, H At least one of gZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe and HgZnSTe; the IV-VI group compound is selected from SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, P bSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe; the III-V compound is selected from GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, At least one of 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.

[0085] 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.

[0086] It should be noted that for the materials of the aforementioned single-structure quantum dots, or the materials of the core of the core-shell quantum dots, or the materials of the shell of the core-shell quantum dots, 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。

[0087] The perovskite semiconductor material can be selected from but not limited to doped or undoped inorganic perovskite semiconductors, or organic-inorganic hybrid perovskite semiconductors; the inorganic perovskite semiconductor has the general structural formula 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 .

[0088] In some embodiments, the optoelectronic device 100 further includes an electron transport layer 30, which is disposed between the first electrode and the hole functional layer. Specifically, the electron transport layer 30 is located between the hole functional layer and the cathode 40. When the optoelectronic device 100 further includes a light-emitting layer 20, the electron transport layer 30 is located between the light-emitting layer 20 and the cathode 40. The electron transport layer 30 can be prepared using materials known in the art for use in optoelectronic devices 100 that have electron transport properties. For example, the material of the electron transport layer 30 includes but is not limited to at least one of metal oxides, doped metal oxides, II-VI semiconductor materials, III-V semiconductor materials and I-III-VI semiconductor materials, the metal oxide is selected from at least one of ZnO, BaO, TiO2, and SnO2; the metal oxide in the doped metal oxide is selected from at least one of ZnO, TiO2, and SnO2, the doping element is selected from at least one of Al, Mg, Li, In, and Ga, the II-VI semiconductor material is selected from at least one of ZnS, ZnSe, and CdS; the III-V semiconductor material is selected from at least one of InP and GaP; the I-III-VI semiconductor material is selected from at least one of CuInS and CuGaS.

[0089] It is understood that the thickness of each layer in the optoelectronic device 100 can be set as needed and is not limited here. In some embodiments, the thickness of the first electrode is 10-100 nm, the thickness of the hole injection layer 60 is 30-100 nm, the thickness of the hole transport layer 50 is 30-100 nm, the thickness of the light-emitting layer 20 is 10-50 nm, the thickness of the electron transport layer 30 is 20-50 nm, and the thickness of the second electrode is 30-100 nm.

[0090] When there are multiple film layers between the anode 10 and the cathode 40, and the multiple film layers are selected from the light-emitting layer 20, the electron transport layer 30, 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 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 the anode 10, the hole injection layer 60, the hole transport layer 50, the light-emitting layer 20, the electron transport layer 30 and the 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 the cathode 40, the electron transport layer 30, the light-emitting layer 20, the hole transport layer 50, the hole injection layer 60 and the anode 10 stacked in sequence from bottom to top.

[0091] It is understandable that the optoelectronic device 100 may further 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 injection layer, an electron blocking layer, a hole blocking layer, an interface modification layer, etc.

[0092] 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 .

[0093] During actual preparation, the various film layers of the optoelectronic device 100, such as the anode 10, the light-emitting layer 20, the electron transport layer 30, and the cathode 40, can be prepared using conventional techniques in the art, such as chemical methods or physical methods. Chemical methods include chemical vapor deposition, continuous ion layer adsorption and reaction, anodic oxidation, electrolytic deposition, and co-precipitation. Physical methods include physical plating and solution methods. Physical plating methods include thermal evaporation, electron beam evaporation, magnetron sputtering, multi-arc ion plating, physical vapor deposition, atomic layer deposition, and pulsed laser deposition. Solution methods can include spin coating, printing, inkjet printing, doctor blade coating, printing, dip-coating, immersion, spraying, roller coating, casting, slot coating, and strip coating.

[0094] In a fourth aspect, the present application further provides 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 smartphones, tablet computers, laptop computers, digital cameras, digital video cameras, smart wearable devices, smart weighing electronic scales, vehicle-mounted displays, televisions, or e-book readers. Examples of smart wearable devices include smart bracelets, smart watches, and virtual reality (VR) helmets.

[0095] The technical solutions and technical effects of the present application are described in detail below through specific embodiments, comparative examples and experimental examples. The following embodiments are only some embodiments of the present application and do not specifically limit the present application.

[0096] Film Example 1

[0097] The film preparation method is as follows:

[0098] (1) Weigh the materials according to the mass ratio of the hole functional material to the additive of 92:8. The hole functional material is TFB and the additive is 1-methoxynaphthalene.

[0099] (2) Add the above materials to chlorobenzene and stir to obtain a mixed solution with a hole functional material concentration of 8 mg / ml.

[0100] (3) The mixed solution was spin-coated on a glass substrate at a rotation speed of 3000 r / min for 30 s, and then annealed at a temperature of 230° C. for 30 min to obtain a thin film with a thickness of 40 nm.

[0101] Film Example 2

[0102] This film embodiment is substantially the same as film embodiment 1, with the only difference being that, in this film embodiment:

[0103] The additive is naphthalene.

[0104] Film Example 3

[0105] This film embodiment is substantially the same as film embodiment 1, with the only difference being that, in this film embodiment:

[0106] The additive is terthiophene.

[0107] Film Example 4

[0108] This film embodiment is substantially the same as film embodiment 1, with the only difference being that, in this film embodiment:

[0109] The additive is a mixture of terthiophene and indene, and the molar ratio of the two is 1:1.

[0110] Film Example 5

[0111] This film embodiment is substantially the same as film embodiment 1, with the only difference being that, in this film embodiment:

[0112] The mass ratio of the hole functional material to the additive is 95:5.

[0113] Film Example 6

[0114] This film embodiment is substantially the same as film embodiment 1, with the only difference being that, in this film embodiment:

[0115] The mass ratio of the hole functional material to the additive is 90:10.

[0116] Film Example 7

[0117] This film embodiment is substantially the same as film embodiment 1, with the only difference being that, in this film embodiment:

[0118] The mass ratio of the hole functional material to the additive is 85:15.

[0119] Film Example 8

[0120] This film embodiment is substantially the same as film embodiment 1, with the only difference being that, in this film embodiment:

[0121] The mixed solution consists of a hole functional material and an additive, and the hole functional material is PEDOT:PSS; the annealing temperature is changed to 200°C.

[0122] Film Comparative Example 1

[0123] TFB was added to chlorobenzene and stirred to obtain a TFB solution with a concentration of 8 mg / ml.

[0124] The TFB solution was spin-coated on a glass substrate at a rotation speed of 3000 r / min for 30 s, and then annealed at a temperature of 230° C. for 30 min to obtain a thin film with a thickness of 40 nm.

[0125] Film Comparative Example 2

[0126] The PEDOT:PSS solution was spin-coated on a glass substrate at a rotation speed of 3000 r / min for 30 s, and then annealed at 200° C. for 30 min to obtain a thin film with a thickness of 40 nm.

[0127] Device Example 1

[0128] The preparation method of the QLED device is as follows:

[0129] (1) The patterned ITO glass substrate was ultrasonically cleaned in acetone, washing solution, deionized water, and isopropyl alcohol in sequence, with each ultrasonic cleaning lasting 20 minutes. After cleaning, it was blown dry with a nitrogen gun. Then, the ITO glass substrate was cleaned in oxygen plasma for another 10 minutes, and then the surface of the ITO glass substrate was treated with ultraviolet-ozone for 15 minutes to obtain an anode with a thickness of 10 nm.

[0130] (2) In air, a layer of PEDOT:PSS was spin-coated on the anode surface at 3000 rpm for 30 seconds. The anode was then annealed at 150°C for 20 minutes to obtain a hole injection layer with a thickness of 80 nm. After annealing, the substrate was transferred to a glove box filled with nitrogen.

[0131] (3) The mixed solution prepared in Example 1 was spin-coated on the surface of the hole injection layer at a speed of 3000 r / min for 30 s, and then annealed at 230° C. for 30 min to obtain a hole transport layer with a thickness of 40 nm.

[0132] (4) After the semi-finished product obtained in step (3) is cooled, 40 mg / ml of blue quantum dot material CdZnSe / ZnSe / Cd / Cd is spin-coated on the surface of the hole transport layer at a speed of 1500 r / min. 0.6 ZnS2 was spin-coated for 30 seconds and then annealed at 100°C for 5 minutes to obtain a light-emitting layer with a thickness of 25 nm.

[0133] (5) A 40 mg / ml ZnO ethanol solution was spin-coated on the surface of the light-emitting layer at a speed of 3000 r / min for 30 s, and then annealed at a temperature of 100° C. for 15 min to obtain an electron transport layer with a thickness of 30 nm.

[0134] (6) The semi-finished product obtained in step (5) is placed in a vacuum cavity, and a layer of silver with a thickness of 100 nm is evaporated on the surface of the electron transport layer as a cathode, and encapsulated to obtain a QLED device.

[0135] Device Examples 2 to 7

[0136] The scheme of device embodiment m is basically the same as that of device embodiment 1, with the only difference being that in device embodiment m, in step (3), the mixed solution used to prepare the hole transport layer is changed to the mixed solution prepared in thin film embodiment m, wherein m is 2 to 7.

[0137] Device Example 8

[0138] The device embodiment scheme is basically the same as the device embodiment 1, with the only difference being that, in the device embodiment, the hole injection layer is doped with additives during preparation, and the hole transport layer is prepared using conventional methods, and accordingly:

[0139] 1. In step (3), the material used to prepare the hole transport layer was changed to a chlorobenzene solution of TFB with a concentration of 8 mg / ml;

[0140] 2. In step (2), the material used to prepare the hole injection layer is changed to the mixed solution prepared in thin film example 8.

[0141] Device Example 9

[0142] The device embodiment scheme is basically the same as the device embodiment 1, except that, in the device embodiment, both the hole transport layer and the hole injection layer are doped with additives during preparation:

[0143] In step (2), the material used to prepare the hole injection layer is changed to the mixed solution prepared in thin film example 8.

[0144] Device Comparative Examples 1 and 2

[0145] The device comparative example n is substantially the same as that of the device embodiment 1, except that:

[0146] In step (3), the material used to prepare the hole transport layer is changed to the solution prepared in thin film comparative example n, wherein n is 1 or 2.

[0147] Experimental Example 1

[0148] (1) The film prepared in Film Example 1 was used as an experimental group, and the film prepared in Film Comparative Example 1 was used as a control group. The films in the experimental and control groups were observed using an atomic force microscope (AFM). The results are shown in Figures 4 and 5.

[0149] (2) Take the films prepared in Examples 1 to 8 and Comparative Examples 1 to 2, and use an atomic force microscope (AFM) to measure the root mean square roughness Rq of the films, and record it in Table 1.

[0150] Table 1

[0151] From Figures 4 and 5, it can be seen that the films in the experimental group are more uniform, have smaller surface roughness, and have better surface morphology; from the data in Table 1, it can be seen that the films of Examples 1 to 7 have a lower root mean square roughness Rq than that of the film comparison example 1, and the film of Example 8 has a lower root mean square roughness Rq than that of the film comparison example 2, indicating that the addition of additives makes the arrangement between the hole functional materials more regular, reduces irregular local excessive agglomeration, and thus significantly improves the film morphology.

[0152] Experimental Example 2

[0153] Hole transport performance testing: A QLED efficiency test system was built using LabView to control QE PRO and Keithley 2400. This system measured the current density-voltage curve of a single-carrier transport thin-film device (HOD / EOD). The current density at the device's operating voltage (6V) was compared with the operating voltage at steady state. The steady-state operating voltage refers to the operating voltage at the device's equilibrium stage after the device has operated for more than 4 hours during the device life test. Here's the breakdown:

[0154] The preparation method of the hole-only device (HOD) is basically the same as that of its corresponding complete QLED device, with the only difference being that the electron transport layer is subtracted.

[0155] In the above tests, the devices used are single-hole devices corresponding to the QLED devices in the above-mentioned device embodiments 1 to 9 and device comparison examples 1-2.

[0156] Table 2

[0157] As can be seen from the table above:

[0158] Compared with the single-hole device of device comparison example 1, device embodiments 1 to 7 and 9 all have higher current efficiency and lower operating voltage. At the same time, compared with device comparison example 2, device embodiments 8 and 9 all have higher current efficiency and lower operating voltage, indicating that the addition of additives when preparing the hole functional layer helps to improve the hole transport and injection performance of the film layer, thereby improving the electrical performance of the device.

[0159] Experimental Example 3

[0160] The quantum dot light-emitting diodes of device examples 1-9 and device comparative examples 1-2 were subjected to performance tests, and the test results are shown in Table 3. The test method is as follows:

[0161] (1) The external quantum efficiency (EQE) is measured as the ratio of the number of electron-hole pairs injected into quantum dots to the number of emitted photons. The unit is %, which is an important parameter for measuring the quality of electroluminescent devices. It can be obtained by measuring with an EQE optical test instrument. The specific calculation formula is as follows:

[0162] Where ηe is the light output coupling efficiency, ηγ is the ratio of the number of recombined carriers to the number of injected carriers, x is the ratio of the number of excitons that generate photons to the total number of excitons, KR is the rate of the radiative process, and KNR is the rate of the non-radiative process.

[0163] Test conditions: carried out at room temperature, air humidity of 30-60%.

[0164] (2) The test method for lifespan T95@1000nit is:

[0165] The time required for the device's brightness to decrease to a certain percentage of its maximum brightness when driven by a constant current or voltage is defined as T95, the time it takes for the brightness to drop to 95% of its maximum brightness. This lifetime is the actual measured lifetime. To shorten the test cycle, device lifetime testing is usually performed at high brightness by accelerating device aging. The lifetime at high brightness is then calculated using the extended exponential decay brightness decay fitting formula. For example, the lifetime at 1000 nit is calculated as T95@1000 nit. The specific calculation formula is as follows:

[0166] Among them, T95 L For lifespan at low brightness, T95 H is the measured lifetime under high brightness, L H To accelerate the device to the highest brightness, L L The light intensity is 1000 nit, A is the acceleration factor, and this experiment measured the lifespan of several groups of QLED devices at rated brightness and found that the A value was 1.7.

[0167] In the above tests, the devices used in the external quantum efficiency test and the device life test are the QLED devices with complete structures in the above embodiments and comparative examples.

[0168] Table 3

[0169] From Table 3 we can see that:

[0170] Compared with the single-hole device of device comparison example 1, device embodiments 1 to 7 and 9 all have higher EQE and T95@1000nit. At the same time, compared with device comparison example 2, device embodiments 8 and 9 all have higher EQE and T95@1000nit, indicating that the addition of additives during the preparation of the hole functional layer helps to improve the hole transport and injection performance of the film layer, improve the carrier balance of the device, and thus enhance the luminous efficiency and life of the device.

[0171] The above is a detailed introduction to the thin film, preparation method and optoelectronic device provided in the embodiments of the present application. Specific examples are used herein 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, based on the ideas of the present application, there will be changes in the specific implementation methods 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, wherein: The following steps are involved: Providing a mixed solution, the mixed solution comprising a hole functional material and an additive; depositing the mixed solution, and then annealing to remove the additive to obtain a thin film; Wherein, the additive includes a compound having a structure shown in formula (1): Wherein, ring A includes one or more of an aromatic ring having 6 to 40 ring carbon atoms and a heteroaromatic ring having 6 to 40 ring atoms, and n is a positive integer; Each occurrence of X is independently selected from one or more of hydrogen, deuterium, and an electron donating group.

2. The preparation method according to claim 1, wherein The electron donating groups include -NH2, A combination of one or more of C1-C3 alkyl and C1-C3 alkoxy.

3. The preparation method according to claim 1 or 2, wherein Ring A includes one or more of an aromatic ring having 6 to 20 ring carbon atoms and a heteroaromatic ring having 6 to 20 ring atoms.

4. The preparation method according to claim 3, wherein Ring A is selected from one or more rings of any one of the structures shown in formulae (2) to (7):

5. The preparation method according to any one of claims 1 to 4, wherein: n is 1 to 4.

6. The preparation method according to claim 5, wherein: n is 1 or 2.

7. The preparation method according to any one of claims 1 to 6, wherein: The boiling point of the additive is greater than or equal to 100°C and less than 200°C.

8. The preparation method according to claim 7, wherein: The additive includes one or more compounds having a structure shown in any one of the following formulae (8) to (16):

9. The preparation method according to any one of claims 1 to 7, wherein: Each occurrence of X is independently selected from the electron donating groups described.

10. The preparation method according to any one of claims 1 to 7, wherein: The additive includes one or more compounds having a structure represented by any one of formulas (11) to (16):

11. The preparation method according to any one of claims 1 to 10, wherein: The mass of the additive accounts for 5-10% of the total mass of the additive and the hole functional material.

12. The preparation method according to any one of claims 1 to 11, wherein: The hole functional material comprises a hole transport material or a hole injection material, wherein the hole transport material is selected from poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], poly(4-butylphenyl-diphenylamine), poly(triarylamine), polypyrrole, poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine], poly(p-phenylene vinylene), poly[2-methoxy-5-(2-ethylhexyl)- At least one of poly[(2-methoxy)-1,4-phenylene vinylene] and poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene], PEDOT:PSS and its derivatives, poly(N-vinyl carbazole) and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives; the hole injection material is selected from at least one of PEDOT, PEDOT:PSS and copper phthalocyanine.

13. The preparation method according to any one of claims 1 to 12, wherein: In the step of depositing the mixed solution and then annealing to remove the additive to obtain a thin film, the annealing temperature is 200-230°C.

14. The preparation method according to any one of claims 1 to 13, wherein: The annealing time is 15 to 45 minutes.

15. The preparation method according to any one of claims 1 to 14, wherein: The mixed solution also includes a solvent, and the solvent includes one or more of alcohol solvents, chloroform, chlorobenzene, and dichlorobenzene.

16. The preparation method according to any one of claims 1 to 15, wherein: In the mixed solution, the concentration of the hole functional material is 2-15 mg / ml.

17. A film, wherein The material of the film includes a hole functional material, and the root mean square roughness of the film is 0.3-1.

5.

18. The film according to claim 17, wherein The hole mobility of the film is 10 -3 ~10 -1 cm 2 V –1 s –1 .

19. An optoelectronic device, wherein: It comprises a first electrode, a hole functional layer and a second electrode, wherein the hole functional layer comprises one or two layers of a hole injection layer and a hole transport layer, and at least one layer of the hole functional layer comprises the film as claimed in claim 17 or 18, or comprises a film obtained by the preparation method according to any one of claims 1 to 16.

20. The optoelectronic device according to claim 19, wherein The first electrode and the second electrode are each independently 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 optoelectronic device further comprises a light-emitting layer, wherein the light-emitting layer is arranged between the first electrode and the hole functional layer, or the light-emitting layer is arranged between the second electrode and the hole functional layer, and the material of the light-emitting layer is selected from one or more of an organic light-emitting material and a quantum dot light-emitting material, wherein the organic light-emitting material is selected from one or more of 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, delayed fluorescent materials, TTA materials, thermally activated delayed materials, polymers containing BN covalent bonds, hybrid localized charge transfer excited state materials, and exciplex light-emitting materials; the quantum dot light-emitting material is selected from one or more of a single structure quantum dot, a core-shell structure quantum dot, a At least one of 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, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, At least one of HgZnSeS, HgZnSeTe and HgZnSTe; the IV-VI group compound is selected from 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 compound is selected from at least one of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPA s, 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; the perovskite semiconductor material is selected from 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+ 、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 - , at least one of I-.

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