Composition, thin film, preparation method of thin film, light-emitting device and display device

Abstract

The invention discloses a composition, a thin film, a preparation method of the thin film, a light-emitting device and a display device. The composition comprises an organic light-emitting material, an additive and a solvent, and the additive comprises one or more of compounds with HO-L-OH structures; wherein L is selected from a substituted or unsubstituted C2-C12 straight chain alkylene group; the substituent group of the substituted C2-C12 straight chain alkylene comprises one or more of hydroxyl, amino, halogen, carboxyl, nitryl, sulfonic acid group, aldehyde group, sulfydryl, cyano, C1-C5 alkyl, C1-C5 alkoxy and C1-C5 alkyl carbonyl. The additive is added into the composition, so that the composition is easy to crystallize, the micromolecular organic light-emitting material in a solution system can be induced to generate certain micro-aggregation, the film-forming characteristic is improved, the compactness of a printed film is improved, the defects of the film are reduced, and the carrier transport rate of the film is increased.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a composition, a film and a preparation method thereof, a light-emitting device and a display apparatus. Background Art

[0002] The printing method for preparing thin films has the advantages of fast processing speed and patterning, and is widely used in the fields of printed display, thin film preparation, and light-emitting device preparation.

[0003] Luminescent film refers to a film with luminescent properties, which can be prepared by printing film making. At present, the ink used for printing luminescent film is mainly composed of organic luminescent materials and solvents. The film printed with this ink is an amorphous film with disordered molecular arrangement, which leads to poor carrier transport performance. Summary of the invention

[0004] In view of this, the present application provides a composition, a film and a method for preparing the same, a light-emitting device and a display apparatus.

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

[0006] In a first aspect, the present application provides a composition comprising an organic light-emitting material, an additive and a solvent, wherein the additive comprises one or more compounds having a HO-L-OH structure;

[0007] Wherein, L is selected from substituted or unsubstituted C2-C12 straight chain alkylene;

[0008] The substituents of the substituted C2-C12 straight-chain alkylene group include one or more of hydroxyl, amino, halogen, carboxyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, C1-C5 alkyl, C1-C5 alkoxy, and C1-C5 alkylcarbonyl.

[0009] In a second aspect, the present application also provides a film, which is formed by printing the composition described above.

[0010] In a third aspect, the present application also proposes a method for preparing a thin film, comprising the following steps:

[0011] Providing a substrate and the composition described above;

[0012] The composition is printed on one side of the substrate, dried to form a solid film, and then the solid film is annealed to obtain a thin film.

[0013] In a fourth aspect, the present application further proposes a light-emitting device, comprising a cathode, a light-emitting layer and an anode, wherein the light-emitting layer comprises the film described above, or comprises a film prepared by the preparation method described above.

[0014] In a fifth aspect, the present application also proposes a display device, comprising the light-emitting device as described above.

[0015] The technical solution provided by the present application is to add an additive to the composition, wherein the additive structure contains at least two hydroxyl groups, and an alkylene group of a certain chain length is separated between the two, so that the viscosity and surface tension of the composition can be adjusted to obtain a composition suitable for printing; in addition, the configuration of the alkylene group of a certain chain length makes the composition easy to crystallize, and can also induce a certain micro-aggregation of the small molecule luminescent material in the solution system, which helps to improve the film-forming properties, enhance the density of the printed film, reduce film defects, and increase the carrier transfer rate of the film. In addition, this type of additive has a low melting and boiling point, and can be volatilized during high-temperature annealing, avoiding the impact on the performance of the film itself. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] 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.

[0017] Figure 1 is a schematic structural diagram of a light-emitting device proposed in one embodiment of the present application;

[0018] Reference numerals:

[0019] 100 - light-emitting device; 10 - anode; 20 - hole injection layer; 30 - hole transport layer; 40 - light-emitting layer; 50 - electron transport layer; 60 - cathode. DETAILED DESCRIPTION

[0020] 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.

[0021] 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".

[0022] 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.

[0023] 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.

[0024] 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.

[0025] Explanation of terms

[0026] In the present application, "substituted or unsubstituted" means that the defined group may be substituted or unsubstituted. When the defined group is substituted, it is understood that the defined group may be substituted by one or more substituents. When substituted by multiple substituents, each substituent may be the same or different.

[0027] In the present application, "alkyl" refers to a group obtained by removing one hydrogen from an alkane, which can be expressed as a straight-chain alkyl or a branched alkyl. C1-10 alkyl refers to an alkyl group containing 1 to 10 carbon atoms, and each time it appears, it can be independently C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl, C6 alkyl or C10 alkyl. Non-limiting examples of alkyl include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, isobutyl, 2-ethylbutyl, 3,3-dimethylbutyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, 1-methylpentyl, 3-methylpentyl, n-hexyl, etc. "Alkylene" refers to a group obtained by removing one more hydrogen from an alkyl group.

[0028] In this application, hydroxyl refers to -OH; alkoxy has the structural characteristics of the formula -OR; alkylcarbonyl refers to Wherein, R is selected from an alkyl group.

[0029] In the first aspect, the present application provides a composition, which can be used as ink for printing methods such as inkjet printing, spin coating, and blade coating to prepare a light-emitting film. In some embodiments, the composition includes an organic light-emitting material, an additive, and a solvent, wherein the additive includes one or more compounds having a structure as shown in formula (1);

[0030] Formula (1): HO-L-OH;

[0031] Wherein, L is selected from substituted or unsubstituted C2-C12 straight chain alkylene;

[0032] The substituents of the substituted C2-C12 straight-chain alkylene group include one or more of hydroxyl, amino, halogen, carboxyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, C1-C5 alkyl, C1-C5 alkoxy, and C1-C5 alkylcarbonyl.

[0033] The technical solution provided by the present application is to add an additive to the composition, wherein the additive structure contains at least two hydroxyl groups, and an alkylene group of a certain length is separated between the two, and the hydroxyl groups at both ends are defined as the first hydroxyl group and the second hydroxyl group, wherein the first hydroxyl group can act on the organic light-emitting material, and the second hydroxyl group is used to regulate the hydrophilicity of the solvent surface, and at the same time, a limited number of alkylene groups can regulate the hydrophobicity, and the alkylene group and the second hydroxyl group act together to accurately regulate the viscosity and surface tension of the composition; at the same time, the configuration of the alkylene group of a certain length makes the composition easy to crystallize, and can also induce the small molecule light-emitting material in the solution system to produce a certain micro-aggregation, forming a micro-aggregation structure, which helps to improve the film-forming properties, improve the density of the printed film, reduce film defects, and increase the carrier transfer rate of the film. In addition, this type of additive has a low melting and boiling point, and can be volatilized during high-temperature annealing, avoiding the impact on the performance of the film itself.

[0034] In some embodiments of the present application, the boiling point of the additive is less than or equal to 350° C. By selecting an additive with a boiling point less than or equal to 350° C., after the film is printed and formed, when the film is subjected to high temperature annealing, the additive can be fully volatilized to avoid residue.

[0035] In some embodiments of the present application, L is selected from substituted or unsubstituted C6-C10 straight-chain alkylene; in other embodiments of the present application, the substituent is selected from one or more of hydroxyl and C1-C5 alkyl.

[0036] Further, in some specific embodiments of the present application, the additive includes one or more compounds having the following structures: HO(CH2)6OH (1,6-hexanediol), HO(CH2)7OH (1,7-heptanediol), HO(CH2)8OH (1,8-octanediol), HO(CH2)9OH (1,9-nonanediol), HO(CH2) 10 OH (1,10-decanediol). The above compound has the properties shown in Table 1 below.

[0037] Table 1

[0038] name Molecular weight Melting point(℃) Boiling point(℃) 1,6-Hexanediol 118.17 43 250 1,7-Heptanediol 132.2 22 262 1,8-Octanediol 146.2 61 279 1,9-Nonanediol 160.25 45 292 1,10-Decanediol 174.28 73 304

[0039] In some embodiments, in the composition, the mass percentage of the additive is 0.01-2%; for example, it can be 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.5%, 0.8%, 1%, 1.5%, 1.8%, 2% and values ​​between any two of the above values.

[0040] In some embodiments, in the composition, the mass percentage of the organic light-emitting material is 0.1-5%; for example, it can be 0.1%, 0.2%, 0.3%, 0.5%, 0.8%, 1%, 1.5%, 1.8%, 2%, 3%, 4%, 5% and values ​​between any two of the above values.

[0041] In some embodiments, the composition may further contain other additives, including but not limited to viscosity additives, etc. The viscosity additives may be ether compounds, ester compounds, etc.

[0042] It can be understood that in the composition, the content of the solvent is the balance, specifically, the sum of the mass percentages of all components of the composition is 100%.

[0043] Specifically, in some embodiments, in the composition, the mass percentage of the solvent is 93-99.89%; for example, it can be 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.89% and values ​​between any two of the above values.

[0044] The solvent may be an organic solvent commonly used in luminous film inks in the art, and may include, but is not limited to, one or more of methyl benzoate, ethyl benzoate, ethyl p-methyl benzoate, isobutyl benzoate, ethylhexyl benzoate, cyclohexylbenzene, 1-hexylbenzene, 1-heptylbenzene, 1-octylbenzene, 1-decylbenzene, 1,1'-diisopropylbiphenyl, 4,4'-diethylbiphenyl, 3,4'-diisopropylbiphenyl, and 4,4'-diisopropylbiphenyl.

[0045] The organic light-emitting material can be an organic light-emitting material commonly used in the art for preparing organic light-emitting films. In some embodiments, the organic light-emitting material includes one or more of a blue light-emitting material, a red-green light-emitting material, wherein the blue light-emitting material includes a blue light host light-emitting material and a blue light guest light-emitting material, and the red-green light-emitting material includes a red-green host light-emitting material and a red-green host light-emitting material; wherein the blue light host light-emitting material may include but is not limited to one or more of the compounds of the structures shown in formulas I1 to I21, the blue light guest light-emitting material may include but is not limited to one or more of the compounds of the structures shown in formulas J1 to J19, the red-green host light-emitting material may include but is not limited to a p-type host light-emitting material or an n-type host light-emitting material, the p-type host light-emitting material may include but is not limited to one or more of the compounds of the structures shown in formulas p-Host-1 to p-Host-38, the n-type host light-emitting material may include but is not limited to one or more of the compounds of the structures shown in formulas n-Host-1 to n-Host-12, and the red-green guest light-emitting material may include but is not limited to one or more of the compounds of the structures shown in formulas M-1 to M-20. The compounds listed above are all known compounds in the art and can be purchased on the market. For example, the compound corresponding to I19 is 9,10-di(2-naphthyl)anthracene (CAS: 122648-99-1); the compound corresponding to I20 is 2-methyl-9,10-di(2-naphthyl)anthracene (CAS: 804560-00-7); and the compound corresponding to I21 is 2-tert-butyl-9,10-di(2-naphthyl)anthracene (CAS: 274905-73-6). The compounds corresponding to P-Host-36 to P-Host-38 are CBP (4,4'-bis(9-carbazole)biphenyl), CAS: 58328-31-7; mCBP (3,3'-bis(N-carbazole)-1,1'-biphenyl), CAS: 342638-54-4; TCTA (4,4',4"-tri(carbazole-9-yl)triphenylamine), CAS: 139092-78-7. The compounds corresponding to Host-9 to Host-12 are TPBi (1,3,5-tri(1-phenyl-1H-benzimidazole) oxadiazole (1,3,4-dioxadiazole; CAS: 138372-67-5); and the like.

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052] In some embodiments of the present application, the viscosity of the composition at 25°C is 1 to 10 cp; for example, it can be 1 cp, 2 cp, 3 cp, 4 cp, 5 cp, 6 cp, 7 cp, 8 cp, 9 cp, 10 cp, and values ​​between any two of the above values. The viscosity of the composition proposed in the embodiments of the present application is within an appropriate range and has a good film-forming effect.

[0053] In some embodiments of the present application, the surface tension of the composition is 28-40 mN / m; for example, it can be 28 mN / m, 29 mN / m, 30 mN / m, 31 mN / m, 32 mN / m, 33 mN / m, 34 mN / m, 35 mN / m, 36 mN / m, 37 mN / m, 38 mN / m, 39 mN / m, 40 mN / m and values ​​between any two of the above values. The surface tension of the composition proposed in the embodiments of the present application is within a suitable range and has a good film-forming effect.

[0054] Based on the above composition embodiment, a preparation method of the composition is proposed, the preparation method comprising: mixing the components of the composition uniformly, then heating and stirring at 50-100°C for 0.5-24h to dissolve the components, and then filtering to obtain the composition. The mixing method can be oscillation, ultrasound, shaking, etc.; the filtration can be performed using a PTFE 0.2um filter head.

[0055] In a second aspect, the present application also proposes a thin film, which is formed by printing the composition described above. The thin film has good compactness, uniform film formation, good effect and high carrier transmission efficiency.

[0056] In a third aspect, the present application also proposes a method for preparing a thin film, comprising the following steps:

[0057] S10, providing a substrate and the composition described above;

[0058] S20, printing the composition on one side of the substrate, drying to form a solid film, and then annealing the solid film to obtain a thin film.

[0059] In step S10, the substrate may be a prefabricated device or a film layer on which a film is to be set in a semi-finished device. For example, when the device structure is cathode 60 / film / anode 10, the surface of cathode 60 or anode 10 may be used as a substrate for preparing a 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.

[0060] In some embodiments, the annealing temperature is 80-150°C; for example, it can be 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, and values ​​between any two of the above values; in some embodiments, the annealing time is 15-20 min; for example, it can be 15 min, 16 min, 17 min, 18 min, 19 min, 20 min, and values ​​between any two of the above values.

[0061] In a fourth aspect, the present application further provides a light emitting device 100, which may be an organic light emitting diode (OLED). Figure 1 The light emitting device 100 includes a cathode 60, a light emitting layer 40 and an anode 10 which are stacked in sequence. The light emitting layer 40 includes the film described above, or includes a film prepared by the preparation method described above.

[0062] The anode 10 may be an anode 10 for a light-emitting 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.

[0063] The cathode 60 can be a cathode 60 for the light-emitting 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.

[0064] In some embodiments, the light emitting device 100 further includes an electron transport layer 50, and the electron transport layer 50 is disposed between the light emitting layer 40 and the cathode 60. The material of the electron transport layer 50 can be a material known in the art for preparing the electron transport layer 50, for example, an organic small molecule electron transport material, and the organic small molecule electron transport material can include but is not limited to 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi), 2,7-bis(diphenylphosphinyl)-9,9'-spirobifluorene (SPPO13), 2,7-bis(diphenylphosphinyl)-9,9'-spirobifluorene and one or more of the mixed doping materials of n-dopant materials, wherein the n-dopant material can be 8-hydroxyquinoline lithium (Liq).

[0065] In some embodiments, the light-emitting device 100 further includes a hole functional layer disposed between the light-emitting layer 40 and the anode 10, and the hole functional layer includes one or two layers of a hole transport layer 30 and a hole injection layer 20. When the hole functional layer includes the hole transport layer 30 and the hole injection layer 20, the hole transport layer 30 and the hole injection layer 20 are stacked, and the hole injection layer 20 is located between the hole transport layer 30 and the anode 10. The hole functional layer can be prepared using a hole functional material known in the art for the light-emitting device 100 and having a hole transport property or a hole injection property. Specifically, the material of the hole transport layer 30 may include, but is not limited to, poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine) (TFB), polyvinylcarbazole (PVK), poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine) (poly-TPD), poly(9,9-dioctylfluorene-co-bis-N,N-phenyl-1,4-phenylenediamine) (PFB), 4,4',4"-tri(carbazole-9-yl)triphenylamine (TCATA), 4,4'-bis(9-carbazole)biphenyl (CBP), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD), N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB), poly(3,4-ethylenedioxythiophene) The hole injection layer 20 may include at least one of PEDOT:PSS (poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) (PEDOT:PSS), Spiro-NPB, Spiro-TPD, doped graphene, undoped graphene, C60, doped or undoped NiO, doped or undoped MoO3, doped or undoped WO3, doped or undoped V2O5, p-type gallium nitride, doped or undoped CrO3, and doped or undoped CuO; the material of the hole injection layer 20 may include but is not limited to PEDOT:PSS (poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid), CuPc, TiOPc (titanium phthalocyanine), m-MTDATA (CAS: 124729-98-2), 2-TNATA (4,4',4"-tris(2-naphthylphenylaminotriphenylamine)), transition metal oxides, and transition metal sulfur compounds. Among them, the transition metal oxides include one or more of NiO, MoO3, WO3, CrO3, and CuO; the metal sulfur compounds include one or more of MoS2, MoSe2, WS3, WSe3, and CuS.

[0066] It is understandable that the light emitting device 100 may further be provided with some functional layers conventionally used in the light emitting device 100 to help improve the performance of the light emitting device 100, such as an electron blocking layer, a hole blocking layer, etc.

[0067] It can be understood that the materials of each layer of the light emitting device 100 can be adjusted according to the actual requirements of the light emitting device 100 .

[0068] It can be understood that the light emitting device 100 can be an upright device or an inverted device.

[0069] When there are multiple film layers between the anode 10 and the cathode 60, and the multiple film layers are selected from the light-emitting layer 40, the electron transport layer 50, the hole transport layer 30, and the hole injection layer 20, the film layer stacking order of the light-emitting device 100 is the anode 10, the hole injection layer 20, the hole transport layer 30, the light-emitting layer 40, the electron transport layer 50 and the cathode 60; it can be understood that the light-emitting device 100 can be a positive device or an inverted device. In some embodiments, the light-emitting device 100 is a positive device, and accordingly, the light-emitting device 100 includes the anode 10, the hole injection layer 20, the hole transport layer 30, the light-emitting layer 40, the electron transport layer 50 and the cathode 60 stacked in sequence from bottom to top; in other embodiments, the light-emitting device 100 is an inverted device, and accordingly, the light-emitting device 100 includes the cathode 60, the electron transport layer 50, the light-emitting layer 40, the hole transport layer 30, the hole injection layer 20 and the anode 10 stacked in sequence from bottom to top.

[0070] Based on the above embodiment of the light-emitting device 100, the present application further proposes a method for preparing the light-emitting device 100, the method comprising the following steps: preparing a plurality of film layers in sequence according to a preset film layer sequence to obtain the light-emitting device 100; wherein the plurality of film layers include a first electrode, a second electrode, and at least one functional layer disposed between the first electrode and the second electrode, the at least one functional layer including at least one of an electron transport layer 50, a hole transport layer 30, and a hole injection layer 20, and a light-emitting layer 40. The preparation of the light-emitting layer 40 may refer to the preparation method of the above thin film embodiment.

[0071] The preset film layer sequence refers to the sequence in which the light emitting device 100 is stacked from bottom to top.

[0072] In the light-emitting device 100 provided in the present application, other functional layers, the first electrode and the second electrode other than the light-emitting layer 40 can also be prepared by conventional preparation methods. 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, anodization, electrolytic deposition, and coprecipitation. The physical method includes physical plating and solution method, among which the physical plating method includes: thermal evaporation coating, electron beam evaporation coating, magnetron sputtering, multi-arc ion plating, physical vapor deposition, atomic layer deposition, pulsed laser deposition, etc.; the solution method can be spin coating, printing, inkjet printing, blade coating, printing, dip pulling, immersion, spraying, roller coating, casting, slit coating and strip coating, etc.

[0073] In some embodiments, after the above-mentioned film structure is made, the step of packaging the light-emitting device 100 is also included. The packaging process can be a common machine packaging or a manual packaging. Preferably, in the environment of the packaging process, the oxygen content and the water content are both less than 0.1ppm to ensure the stability of the light-emitting device 100.

[0074] In addition, the present application also proposes a display device, which may be a smart phone, a portable phone, a tablet computer, a personal digital assistant (PDA), a portable multimedia player (Portable Multimedia Player), a television, a game console, a watch-type electronic device, a head-mounted display, a display of a personal computer, a notebook computer, a car navigation system, a car dashboard, a digital camera, a portable camera, an external advertising board, an electro-optical board, a medical device, a detection device, a refrigerator, a washing machine, etc. The display device includes the light-emitting device 100 as described above.

[0075] 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.

[0076] Material Example 1

[0077] The composition includes 1.75wt% organic light-emitting material, 0.5wt% additive and 97.75wt% solvent. The organic light-emitting material is composed of main light-emitting material mCBP and phosphorescent doped light-emitting material Ir(mppy)3, the main light-emitting material mCBP accounts for 1.65wt% in the composition, and the phosphorescent doped light-emitting material Ir(mppy)3 accounts for 0.10wt% in the composition; the additive is 1,8-octanediol; and the solvent is methyl benzoate.

[0078] The preparation steps of the composition are as follows: the main luminescent material, phosphorescent doped luminescent material and additives are added to a solvent, stirred at 80°C for 12 hours to completely dissolve all the materials in the solvent, and then filtered through a 0.2um PTFE filter head to obtain a composition GEM-1. After testing, the viscosity is 2.9cp and the surface tension is 33.8mN / m.

[0079] Preparation of thin film: The composition prepared by the above method was spin-coated on a glass substrate by spin coating, and then the substrate containing the composition was moved to a vacuum drying chamber, and the residual solvent was removed by vacuum to form a solid film; then, it was annealed on a hot plate at 140°C for 20 minutes to obtain a film with a thickness of 40 nm.

[0080] Material Example 2

[0081] The scheme of this embodiment is basically the same as that of embodiment 1, except that in this embodiment, the proportion of the additive is changed from 0.5wt% to 0.01wt%. After testing, its viscosity is 2.88cp and its surface tension is 33.4mN / m.

[0082] Material Example 3

[0083] The scheme of this embodiment is basically the same as that of embodiment 1, except that in this embodiment, the proportion of the additive is changed from 0.5wt% to 2wt%. After testing, the viscosity is 2.95cp and the surface tension is 33.2mN / m.

[0084] Material Example 4

[0085] The scheme of this embodiment is basically the same as that of embodiment 1, except that in this embodiment, the proportion of the additive is changed from 0.5wt% to 2.2wt%. The viscosity is 2.98cp and the surface tension is 33.3mN / m after testing.

[0086] Material Example 5

[0087] The scheme of this embodiment is basically the same as that of embodiment 1, except that in this embodiment, the additive is changed from 1,8-octanediol to 1,6-hexanediol. The viscosity is 2.82cp and the surface tension is 32.8mN / m.

[0088] Material Example 6

[0089] The scheme of this embodiment is basically the same as that of embodiment 1, except that in this embodiment, the additive is changed from 1,8-octanediol to 1,9-nonanediol. The viscosity is 2.95 cp and the surface tension is 33.2 mN / m.

[0090] Material Example 7

[0091] The scheme of this embodiment is basically the same as that of embodiment 1, except that in this embodiment, the additive is changed from 1,8-octanediol to 1,10-decanediol. The viscosity is 3.05 cp and the surface tension is 33.5 mN / m.

[0092] Material Example 8

[0093] The composition includes 0.87wt% organic light-emitting material, 0.2wt% additive and 98.93wt% solvent. The organic light-emitting material is composed of main light-emitting material I9 and guest doped light-emitting material J7, the main light-emitting material I9 accounts for 0.85wt% of the composition, and the guest doped light-emitting material J7 accounts for 0.02wt% of the composition; the additive is 1,7-heptanediol; the solvent is a mixed solvent composed of ethyl p-methylbenzoate and 3,4'-diisopropylbiphenyl, and the mass ratio of ethyl p-methylbenzoate and 3,4'-diisopropylbiphenyl is 4:1.

[0094] The preparation steps of the composition are as follows: the main luminescent material, the guest-doped luminescent material and the additive are added into a mixed solvent, stirred at 80°C for 12 hours to completely dissolve all the materials in the mixed solvent, and then filtered through a 0.2um PTFE filter head to obtain a composition GEM-1. After testing, the viscosity is 3.86cp and the surface tension is 33.5mN / m.

[0095] Preparation of the film: The composition prepared by the above method was printed on a glass substrate by inkjet printing. Then, the substrate containing the composition was moved to a vacuum drying chamber, and the residual solvent was removed by vacuum to form a solid film. Then, the film was annealed on a hot plate at 140°C for 20 minutes to obtain a film with a thickness of 40 nm.

[0096] Material Example 9

[0097] The composition includes 1.7wt% organic light-emitting material, 0.2wt% additive and 98.1wt% solvent. The organic light-emitting material is composed of p-type main light-emitting material p-Host-22, n-type main light-emitting material n-Host-4 and phosphorescent doped light-emitting material Ir(piq)2(acac), p-Host-22 accounts for 1.1wt% of the composition, n-Host-4 accounts for 0.55wt% of the composition, and Ir(piq)2(acac) accounts for 0.05wt% of the composition; the additive is 1,8-octanediol; the solvent is a mixed solvent composed of ethyl p-toluate and 1,1'-diisopropylbiphenyl, and the mass ratio of ethyl p-toluate and 1,1'-diisopropylbiphenyl is 4:1.

[0098] The preparation steps of the composition are as follows: the above-mentioned organic light-emitting materials and additives are added to a mixed solvent, stirred at 80°C for 12 hours to completely dissolve all the materials in the mixed solvent, and then filtered using a 0.2um PTFE filter head to obtain a composition GEM-1. After testing, its viscosity is 3.8cp and its surface tension is 32.8mN / m.

[0099] Preparation of the film: The composition prepared by the above method was printed on a glass substrate by inkjet printing. Then, the substrate containing the composition was moved to a vacuum drying chamber, and the residual solvent was removed by vacuum to form a solid film. Then, the film was annealed on a hot plate at 140°C for 20 minutes to obtain a film with a thickness of 40 nm.

[0100] Material Comparative Example 1

[0101] The scheme of this comparative example is different from Example 1 only in that in this comparative example, the composition does not include additives, and accordingly, the proportion of solvent is changed to 98.25wt%. After testing, its viscosity is 2.82cp and its surface tension is 32.8mN / m.

[0102] Material Comparative Example 2

[0103] The scheme of this comparative example is different from Example 8 only in that in this comparative example, the composition does not include additives, and accordingly, the proportion of the solvent is changed to 99.13wt%, and the mass ratio of the two components in the solvent remains unchanged. After testing, its viscosity is 3.81cp and the surface tension is 33.1mN / m.

[0104] Material Comparative Example 3

[0105] The scheme of this comparative example is different from Example 9 only in that in this comparative example, the composition does not include additives, and accordingly, the proportion of the solvent is changed to 98.3wt%, and the mass ratio of the two components in the solvent remains unchanged. After testing, its viscosity is 3.8cp and the surface tension is 32.8mN / m.

[0106] Material Comparative Example 4

[0107] The scheme of this comparative example is different from that of Example 1 only in that the additive in this comparative example is changed to n-octanol. After testing, its viscosity is 2.82 cp and its surface tension is 32.3 mN / m.

[0108] Material Comparative Example 5

[0109] The scheme of this comparative example is different from that of Example 1 only in that the additive in this comparative example is changed to propylene glycol. After testing, its viscosity is 2.89 cp and its surface tension is 32.5 mN / m.

[0110] Device Example 1

[0111] (1) The ITO (50 nm) substrate was cleaned by ultrasonic cleaning with pure water, baked at 230°C for 1 h, and then treated with UV-ozone for 15 min.

[0112] (2) A layer of PEDOT:PSS was coated on the ITO substrate and annealed on a hot plate at 150°C for 15 min to obtain a hole injection layer with a thickness of 35 nm.

[0113] (3) PVK was spin-coated on the surface of the hole injection layer and annealed on a hot plate at 200° C. for 30 min to obtain a hole transport layer with a thickness of 20 nm.

[0114] (4) After the semi-finished product obtained in step (3) is cooled, the composition obtained in material example 1 is coated on the surface of the hole transport layer by inkjet printing. Then, the substrate containing the composition is moved to a vacuum drying chamber, and the residual solvent is removed by vacuum to form an organic light-emitting layer film. Then, the organic light-emitting layer is annealed on a hot plate at 140° C. for 20 min to obtain a light-emitting layer with a thickness of 40 nm.

[0115] (5) The substrate with the light-emitting layer formed thereon is transferred to a vapor deposition chamber, and TmPyPB is vapor deposited to form an electron transport layer with a thickness of 30 nm. Finally, LiF / Al electrodes are vapor deposited on the electron transport layer with thicknesses of 1 nm and 150 nm to obtain a cathode. After the vapor deposition is completed, a glass cover is used for packaging to obtain a light-emitting device.

[0116] Device Examples 2 to 9

[0117] The scheme of device embodiment n is basically the same as device embodiment 1, with the only difference being that in device embodiment n, in step (4), the spin-coated material is changed to the mixed solution prepared in material embodiment n, and the other steps and parameters remain unchanged, and n is 2 to 9.

[0118] Device Comparative Examples 1 to 5

[0119] The scheme of device comparative example m is basically the same as that of device embodiment 1, except that in device comparative example m, in step (4), the spin-coated material is changed to the mixed solution prepared in material comparative example m, and the other steps and parameters remain unchanged, and m is 1 to 5.

[0120] Experimental example

[0121] The devices prepared in the above device embodiments and device comparative examples were tested, and the results are recorded in Table 2.

[0122] The current of the organic optoelectronic device at different voltages was tested using a Keithley 2400 digital nanovoltmeter, and the current density was obtained by dividing the current by the luminous area. The brightness and radiant energy density of the organic optoelectronic device at different voltages were tested using a Photo Research PR655. Based on the current density and brightness of the organic optoelectronic device at different voltages, the current efficiency CE (cd / A) of the device was obtained.

[0123] Life test refers to the time taken for the device brightness to decay to a certain percentage of the maximum brightness under 2mA constant current drive. The time taken for the brightness to decay to 95% of the maximum brightness is defined as T95, and this life is the measured life. In order to shorten the life test cycle, the device life test is usually carried out at high brightness by accelerating device aging, and the life at low brightness is obtained by fitting the decay fitting formula. For example, the life at 1000nits is recorded as T95 1000nits, and the calculation formula is:

[0124]

[0125] Among them, T95 L The lifespan under low brightness, generally 1000nits, T95 H is the lifespan under high brightness, that is, the measured lifespan, L H is the maximum brightness that the device is accelerated to, L L Generally it is 1000nits, A is the acceleration factor, which is 1.7.

[0126] Table 2

[0127] Voltage @J10(V) CE@1000nit(cd / A) T95_1k nit(h) Device Example 1 4.40 78 27.5 Device Example 2 4.40 78 20.5 Device Example 3 4.40 77 25.2 Device Example 4 4.60 75 16.5 Device Example 5 4.50 77 26.0 Device Example 6 4.50 76 24.5 Device Example 7 4.50 74 18.5 Device Example 8 5.10 4.9 50.0 Device Example 9 4.20 22 504 Device Comparison Example 1 4.60 72 16.2 Device Comparison Example 2 5.40 3.9 28.0 Device Comparison Example 3 4.50 20 302 Device Comparison Example 4 4.60 71 16.0 Device Comparison Example 5 4.70 65 12.0

[0128] From the table above we can see that:

[0129] Device Examples 1 to 7 have a voltage equal to or lower than that of Device Comparative Example 1, and CE and T95_1k nit higher than that of Device Comparative Example 1. Meanwhile, in terms of voltage, CE and T95_1k nit, Device Example 8 is better than Device Comparative Example 2, and Device Example 9 is better than Device Comparative Example 3, indicating that the use of the composition provided in the present application to prepare the light-emitting layer is helpful to improve the carrier transport performance of the film layer, and improve the current efficiency and life of the device. This may be because the additives added to the composition make the composition easy to crystallize, and can also induce a certain amount of micro-aggregation of the small molecule organic light-emitting material in the solution system, which is helpful to improve the film-forming properties, improve the compactness of the printed film, reduce film defects, and improve the carrier transport rate of the film. The macroscopic manifestation is a decrease in device voltage, an increase in current efficiency and a lifespan.

[0130] In addition, compared with device comparison example 1, device comparison examples 4 and 5 not only did not improve in voltage, CE and T95_1knit, but device comparison example 5 even showed a decline in life and current efficiency. This may be because the alkylene chain between the two hydroxyl groups in propylene glycol is too short, resulting in its micro-aggregation effect, crystallinity and dispersibility being reduced, and the resulting light-emitting layer has a poor film-forming effect, which is not conducive to improving device performance. Although n-octanol can act on organic light-emitting materials, its hydrophilicity is poor, which is not conducive to improving the film-forming effect, and has no obvious amplifying effect on the improvement of the film-forming property of the light-emitting layer, so the device performance remains basically unchanged.

[0131] The compositions, films and preparation methods thereof, light-emitting devices and display devices provided in the embodiments of the present application are introduced in detail above. 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 methods and core ideas of the present application. At the same time, for those skilled in the art, according to the ideas of the present application, there will be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present application.

Claims

1. A composition, characterized in that It includes an organic light-emitting material, an additive and a solvent, wherein the additive includes one or more compounds having a HO-L-OH structure; Wherein, L is selected from substituted or unsubstituted C2-C12 straight chain alkylene; The substituents of the substituted C2-C12 straight-chain alkylene group include one or more of hydroxyl, amino, halogen, carboxyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, C1-C5 alkyl, C1-C5 alkoxy, and C1-C5 alkylcarbonyl.

2. The composition according to claim 1, characterized in that The boiling point of the additive is less than or equal to 350°C.

3. The composition according to claim 1, characterized in that L is selected from substituted or unsubstituted C6-C10 straight chain alkylene; and / or, The substituent is selected from one or more of a hydroxyl group and a C1-C5 alkyl group.

4. The composition according to claim 3, characterized in that The additive includes one or more compounds having the following structures: HO(CH2)6OH, HO(CH2)7OH, HO(CH2)8OH, HO(CH2)9OH, HO(CH2) 10 OH.

5. The composition according to claim 1, characterized in that In the composition, the mass percentage of the additive is 0.01-2%; and / or, In the composition, the mass percentage of the organic light-emitting material is 0.1 to 5%; and / or, In the composition, the mass percentage of the solvent is 93-99.89%.

6. The composition according to claim 1, characterized in that The solvent includes one or more of methyl benzoate, ethyl benzoate, ethyl p-methylbenzoate, isobutyl benzoate, ethylhexyl benzoate, cyclohexylbenzene, 1-hexylbenzene, 1-heptylbenzene, 1-octylbenzene, 1-decylbenzene, 1,1'-diisopropylbiphenyl, 4,4'-diethylbiphenyl, 3,4'-diisopropylbiphenyl, and 4,4'-diisopropylbiphenyl; and / or The organic light-emitting material includes one or more of a blue light-emitting material and a red and green light-emitting material; the blue light-emitting material includes a blue light host light-emitting material and a blue light guest light-emitting material, and the red and green light-emitting material includes a red and green host light-emitting material and a red and green host light-emitting material; wherein the blue light host light-emitting material includes one or more of the compounds having structures shown in formulas I1 to I21, the blue light guest light-emitting material includes one or more of the compounds having structures shown in formulas J1 to J19, the red and green host light-emitting materials include a p-type host light-emitting material or an n-type host light-emitting material, the p-type host light-emitting material is selected from one or more of the compounds having structures shown in formulas p-Host-1 to p-Host-38, the n-type host light-emitting material is selected from one or more of the compounds having structures shown in formulas n-Host-1 to n-Host-12, and the red and green guest light-emitting materials include one or more of the compounds having structures shown in formulas M-1 to M-20:

7. The composition according to claim 1, characterized in that The composition has a viscosity of 1 to 10 cp at 25°C; and / or, The surface tension of the composition is 28-40 mN / m.

8. A film, characterized in that: The film is formed by printing the composition according to any one of claims 1 to 7.

9. A method for preparing a thin film, characterized in that: The following steps are involved: Providing a substrate and the composition according to any one of claims 1 to 7; The composition is disposed on one side of the substrate and annealed to obtain a thin film.

10. The preparation method according to claim 9, characterized in that: The annealing temperature is 80-150° C.; and / or; The annealing time is 15 to 20 minutes.

11. A light emitting device, characterized in that: The invention comprises a cathode, a light-emitting layer and an anode, wherein the light-emitting layer comprises the film according to claim 8, or comprises a film prepared by the preparation method according to claim 9 or 10.

12. The light emitting device according to claim 11, characterized in that: The cathode and the anode are 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 light-emitting device further comprises an electron transport layer, wherein the electron transport layer is disposed between the light-emitting layer and the cathode, wherein the material of the electron transport layer comprises an organic small molecule electron transport material, wherein the organic small molecule electron transport material comprises one or more of 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, 2,7-bis(diphenylphosphinyl)-9,9′-spirobifluorene, and N-type doped 2,7-bis(diphenylphosphinyl)-9,9′-spirobifluorene; and / or, The light emitting device further comprises a hole functional layer disposed between the light emitting layer and the anode, wherein the hole functional layer comprises one or two layers of a hole transport layer and a hole injection layer, and the material of the hole transport layer comprises poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine), polyvinylcarbazole, poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine), poly(9,9-dioctylfluorene-co ... -N,N-phenyl-1,4-phenylenediamine), 4,4',4"-tri(carbazole-9-yl)triphenylamine, 4,4'-bis(9-carbazole)biphenyl, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine, N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine, poly(3,4-ethylenedioxythiophene)-poly(phenylene) The material of the hole injection layer includes at least one of PEDOT:PSS, CuPc, phthalocyanine titanium oxide, m-MTDATA, 4,4',4"-tris(2-naphthylphenylaminotriphenylamine), transition metal oxides, and transition metal sulfur compounds; wherein the transition metal oxides include one or more of NiO, MoO3, WO3, CrO3, and CuO; the metal sulfur compounds include one or more of MoS2, MoSe2, WS3, WSe3, and CuS.

13. A display device, characterized in that: Comprising the light emitting device according to claim 11 or 12.

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