Composites, inks, films and light emitting devices

Abstract

This application discloses a composite material, an ink, a thin film, and a light-emitting device. The composite material includes a perovskite material and core-shell structured particles doped in the perovskite material. The core of the core-shell structured particles is a metal particle, and the metal in the metal particle is Au. a Ag b This application introduces a shell coating on the surface of metal particles, which can avoid direct contact between the perovskite material and the metal particles, and also place the perovskite material in an enhanced photoelectric field, thereby effectively improving the luminous efficiency of the perovskite material and giving the composite material a high luminous efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of light-emitting materials, in particular to a composite material, ink, thin film and light-emitting device. BACKGROUND

[0002] Perovskite material is a new type of light-emitting material, which has excellent melting point, thermal conductivity, simple preparation, low cost, adjustable band gap and many other excellent photoelectric properties, and is a very important emerging material. Perovskite-based LED technology is considered to be the next generation of information display technology.

[0003] However, the light-emitting efficiency of the current perovskite material is low and needs to be further improved. SUMMARY

[0004] Therefore, the present application provides a composite material to improve the problem of low light-emitting efficiency of the existing perovskite material.

[0005] The present application is implemented in the following manner. A composite material includes a perovskite material and a core-shell structure particle doped in the perovskite material, the core of the core-shell structure particle is a metal particle, and the metal in the metal particle is Au a Ag b wherein 0≤a≤1, 0≤b≤1, and a+b=1.

[0006] Optionally, in some embodiments of the present application, the a is 0, and the core of the core-shell structure particle is a silver particle; or

[0007] the b is 0, and the core-shell structure particle is a gold particle; or

[0008] neither the a nor the b is 0, and the core-shell structure particle is a gold-silver alloy particle.

[0009] Optionally, in some embodiments of the present application, the material of the shell layer of the core-shell structure particle includes silicon dioxide.

[0010] Optionally, in some embodiments of the present application, the thickness of the shell layer of the core-shell structure particle is 2-10 nm, preferably 3-6 nm; and / or

[0011] the average particle size of the core is 15-80 nm, preferably 30-50 nm.

[0012] Optionally, in some embodiments of the present application, the absorption peak of the core is in the range of 410-550 nm; and / or

[0013] the photoluminescence peak of the perovskite material is in the range of 410-550 nm.

[0014] Optionally, in some embodiments of this application, the perovskite material is perovskite nanocrystals.

[0015] Optionally, in some embodiments of this application, the perovskite nanocrystals are spherical or cubic in shape; and / or

[0016] The perovskite nanocrystals have a particle size of 1–20 nm, preferably 3–5 nm.

[0017] Optionally, in some embodiments of this application, the chemical formula of the perovskite material is CsPbBr. x Cl 3-x Where 0 ≤ x ≤ 3; and / or

[0018] The ratio of perovskite material to the concentration of core-shell structured particles doped in the perovskite material ranges from 4.5 × 10⁻⁶. 2 ~1.0×10 4 ):1.

[0019] Accordingly, embodiments of this application also provide an ink, comprising the aforementioned composite material and a solvent.

[0020] Optionally, in some embodiments of this application, the concentration of perovskite material in the ink is 2.0 × 10⁻⁶. 12 ~6.0×10 12 pcs / mL; and / or

[0021] The concentration of the core-shell structured particles in the ink is 0.6 × 10⁻⁶. 9 ~4.2×10 9 pcs / mL; and / or

[0022] The solvent includes one or more of ethanol, n-hexane, dimethyl sulfoxide, and N,N-dimethylformamide.

[0023] Accordingly, embodiments of this application also provide a thin film comprising the aforementioned composite material.

[0024] Accordingly, embodiments of this application also provide a light-emitting device, including the thin film.

[0025] In the composite material described in this application, the perovskite material is doped with shell-coated metal particles. On the one hand, these metal particles possess excellent local surface plasmon resonance characteristics, enabling the generation of an enhanced local photoelectric field. Within this enhanced photoelectric field, the photoluminescence efficiency of the perovskite material can be significantly improved. On the other hand, the shell coating on the surface of the metal particles separates the perovskite material from the metal particles, thereby preventing fluorescence quenching caused by direct contact between the perovskite material and the metal particles. In summary, by introducing a shell coating on the surface of the metal particles, this application can both prevent direct contact between the perovskite material and the metal particles and place the perovskite material within an enhanced photoelectric field, thereby effectively improving the luminescence efficiency of the perovskite material and giving the composite material a high luminescence efficiency. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a flowchart illustrating a method for preparing a composite material according to an embodiment of this application;

[0028] Figure 2 This is a flowchart of another method for preparing a composite material provided in the embodiments of this application;

[0029] Figure 3 This is a schematic diagram of the structure of a light-emitting device provided in an embodiment of this application;

[0030] Figure 4 This is a schematic diagram showing the distribution and luminescence of core-shell particles and perovskite material in the luminescent thin film formed by the composite material described in this application;

[0031] Figure 5 This is a schematic diagram showing the distribution and luminescence of the core-shell particles and perovskite material in a composite film formed by stacking perovskite layers and core-shell particles.

[0032] Figure 6 This is a TEM image of the silica-coated metal particles from Example 1;

[0033] Figure 7 These are the photoluminescence spectra of the materials in Example 1 and Comparative Example 1;

[0034] Figure 8 This is a comparison of the absorption spectra of the metal particles in Examples 1-5 and the photoluminescence spectrum of the perovskite material in Comparative Example 1.

[0035] Figure 9These are the photoluminescence spectra of luminescent film I and composite luminescent film II. Detailed Implementation

[0036] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0038] In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its actual use or operating state, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". The terms first, second, third, etc., are used merely as illustrative purposes and do not impose numerical requirements or establish a numerical order.

[0039] In this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural.

[0040] In this application, "at least one" means one or more, and "more than one" means two or more. "One or more", "at least one of the following", or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0041] In this application, the term "on" forming another layer on a certain layer is a broad concept. It can mean that the formed other layer is adjacent to a certain layer, or it can mean that there are other spacer structures between the other layer and the certain layer. For example, when a second electrode is formed "on" a first charge carrier functional layer, the term "on" can mean that the formed second electrode is adjacent to the first charge carrier functional layer, or it can mean that there are other spacer structures between the second electrode and the first charge carrier functional layer, such as a light-emitting layer.

[0042] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0043] Currently, although the external quantum efficiency of perovskite green LEDs and perovskite red LEDs has exceeded 25%, the external quantum efficiency of perovskite blue LEDs, which represent one of the three primary colors of display, is far lower than that of perovskite green LEDs and perovskite red LEDs. This greatly restricts the application research of perovskite LEDs for full-color display.

[0044] Although high-proportion halide ion doping and two-dimensional perovskites can achieve blue light, their photoluminescence efficiency is relatively low due to the wide bandgap and surface defects of the perovskite blue light crystal itself. Therefore, the fabrication of high-efficiency perovskite LEDs still faces significant challenges.

[0045] Existing methods for improving the luminescence efficiency of perovskite materials mainly involve ion doping. Doping with ions imparts unique properties to perovskite materials, such as magnetic properties and impurity-related optical properties. For example, incorporating metal ions, such as Mn, into perovskite materials (e.g., cesium lead halide nanocrystals) can be effective. 2+ Bi 3+ While the addition of rare earth ions can improve the photoluminescence efficiency of perovskite materials to some extent, this doping can also create new luminescence bands caused by the dopant ions. These new bands are accompanied by energy transfer from the perovskite matrix to the dopant, which is detrimental to improving the luminescence efficiency of the matrix material itself. Therefore, a method to improve the photoluminescence of perovskites is needed.

[0046] The technical solution of this application is as follows:

[0047] In a first aspect, embodiments of this application provide a composite material comprising a perovskite material and core-shell structured particles doped in the perovskite material, wherein the core of the core-shell structured particles is a metal particle, and the metal in the metal particle is Au. a Ag b Where 0≤a≤1, 0≤b≤1, and a+b=1. In other words, the composite material comprises perovskite material and metal particles coated with a shell and doped in the perovskite material.

[0048] It can be understood that when a is 0, the core of the core-shell structured particle is a silver particle. When b is 0, the core-shell structured particle is a gold particle; when neither a nor b is 0, the core-shell structured particle is a gold-silver alloy particle.

[0049] In the composite material described in this application, the perovskite material is doped with metal particles coated by a shell. On the one hand, the metal particles possess excellent local surface plasmon resonance characteristics, enabling the generation of an enhanced local photoelectric field. Within this enhanced photoelectric field, the photoluminescence efficiency of the perovskite material can be significantly improved. On the other hand, the shell coating on the surface of the metal particles separates the perovskite material from the metal particles, thereby preventing fluorescence quenching caused by direct contact between the perovskite material and the metal particles. In summary, by introducing a shell coating on the surface of the metal particles, this application can both prevent direct contact between the perovskite material and the metal particles and place the perovskite material within an enhanced photoelectric field, thereby effectively improving the luminescence efficiency of the perovskite material and giving the composite material a high luminescence efficiency.

[0050] In some embodiments, the ratio of the concentration of perovskite material to the concentration of core-shell structured particles doped in the perovskite material in the composite material ranges from 4.5 × 10⁻⁶. 2 ~1.0×10 4 ):1. Within the stated range, it can effectively improve the photoluminescence efficiency of perovskite materials and effectively avoid fluorescence quenching of perovskite materials.

[0051] In some embodiments, the shell material of the core-shell structured particle includes silicon dioxide; in other words, the core-shell structured particle is a metal particle coated with silicon dioxide.

[0052] In some embodiments, the thickness of the shell layer is 2–10 nm, for example, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, etc. Within this thickness range, direct contact between the perovskite material and the metal particles can be avoided, while also placing the perovskite material within an enhanced photoelectric field. In at least one preferred embodiment, the thickness of the shell layer is 3–6 nm.

[0053] It is understandable that when the metal particles are gold-silver alloy particles, there is no limitation on the molar ratio of gold and silver elements in the gold-silver alloy particles. As long as they are gold-silver alloy particles, the absorption peak of the metal particles can be made consistent with the photoluminescence peak of the perovskite material, thereby maximizing the resonance enhancement of the photoluminescence intensity of the perovskite material and improving the luminescence efficiency of the perovskite material.

[0054] In some embodiments, the average particle size of the core ranges from 15 to 80 nm, preferably from 30 to 50 nm. Within this particle size range, the absorption peak of the metal particles can be made consistent with the photoluminescence peak of the perovskite material, thereby maximizing the resonance enhancement of the photoluminescence intensity of the perovskite material and improving its luminous efficiency.

[0055] In some embodiments, the absorption peak of the core is 410–550 nm. Within this range, the light emitted by the perovskite material can resonantly excite the surface plasmon effect of the metal core, ensuring a strong photoelectric field induced by surface plasmons.

[0056] It should be noted that the absorption peak of the metal particles mentioned in this application refers to the position of the surface plasmon resonance peak of the metal particles (metal core).

[0057] In some embodiments, the perovskite material is perovskite nanocrystals, and the perovskite nanocrystals may be spherical or cubic in shape.

[0058] In some embodiments, the perovskite nanocrystals have a particle size of 1–20 nm, preferably 3–5 nm. Within this particle size range, the emission peak of the perovskite material has a narrow half-width at half-maximum (WHM), thereby exhibiting higher luminous efficiency, higher color purity, and higher spectral stability.

[0059] In some embodiments, the chemical formula of the perovskite material is CsPbBr x Cl 3-x Where 0 ≤ x ≤ 3. The photoluminescence peak of the perovskite material is 410–550 nm, which coincides with the absorption peak of the metal particles. Thus, the light emitted by the perovskite material can resonate and excite the surface plasmon effect of the metal core, thereby ensuring a strong photoelectric field induced by surface plasmons.

[0060] In some embodiments, the perovskite material CsPbBr x Cl 3-x The ratio of Br and Cl elements can be adjusted to control the properties of perovskite material CsPbBr. x Cl 3-x The position of the photoluminescence peak.

[0061] Furthermore, in some embodiments, x is 0, the perovskite material is CsPbCl3, and the emission peak is 411 nm. In some embodiments, x is 1, the perovskite material is CsPbBrCl2, and the emission peak is 426 nm. In some embodiments, x is 1.5, the perovskite material is CsPbBrCl2. 1.5 Cl 1.5 The emission peak is at 467 nm, at which point the perovskite material emits blue light with high purity. In some embodiments, x is 2, the perovskite material is CsPbBr2Cl, and the emission peak is at 489 nm. In some embodiments, x is 3, the perovskite material is CsPbBr3, and the emission peak is at 518 nm.

[0062] The surface plasmon resonance peak of the silica-coated metal core described in this application is consistent with the emission peak of the perovskite material. This means that the light emitted by the perovskite material can resonate and excite the surface plasmon properties of the silica-coated gold-silver alloy. The local electromagnetic field induced by the surface plasmons, in turn, enhances the luminescence performance of the perovskite material.

[0063] Secondly, embodiments of this application also provide an ink comprising the composite material and solvent described above. In other words, the ink comprises the perovskite material, the core-shell structured particles, and the solvent described above.

[0064] In some embodiments, the concentration of perovskite material in the ink is 2.0 × 10⁻⁶. 12 ~6.0×10 12 cells / mL, for example, 2.0 × 10⁻⁶ 12 cells / mL, 4.0×10 12 cells / mL, 6.0×10 12 per mL.

[0065] In some embodiments, the concentration of the core-shell structured particles in the ink is 0.6 × 10⁻⁶. 9 ~4.2×10 9 cells / mL, for example, 0.6 × 10⁻⁶ 9 cells / mL, 0.8×10 9 cells / mL, 1×10 9 cells / mL, 1.2×10 9 cells / mL, 1.3×10 9 cells / mL, 1.5×10 9 cells / mL, 1.6 × 10 9 cells / mL, 1.8 × 10 9 cells / mL, 2×10 9 cells / mL, 2.4 × 10 9 cells / mL, 2.5×109 cells / mL, 2.8 × 10 9 cells / mL, 3×10 9 cells / mL, 3.2×10 9 cells / mL, 3.3×10 9 cells / mL, 3.5×10 9 cells / mL, 3.6 × 10 9 cells / mL, 3.8 × 10 9 cells / mL, 4×10 9 cells / mL, 4.2×10 9 per mL, etc.

[0066] The solvents include, but are not limited to, one or more of ethanol, n-hexane, dimethyl sulfoxide, and N,N-dimethylformamide.

[0067] Please see Figure 1 This application also provides a method for preparing a composite material, comprising the following steps:

[0068] Step S11: Provide perovskite material, core-shell structured particles and solvent, mix them to obtain ink;

[0069] Step S12: Centrifugation enrichment treatment, drying, to obtain the composite material.

[0070] The perovskite material, core-shell structured particles, and solvents mentioned above will not be repeated here.

[0071] Thirdly, embodiments of this application also provide a thin film, including the composite material described above, or prepared from the ink described above through a film-forming process.

[0072] It is understood that, in at least one embodiment, the thin film is a light-emitting thin film.

[0073] The thin film described in this application includes the composite material described above. Please refer to [link / reference]. Figures 4-5 Compared to the stacked structure formed by perovskite luminescent layers and core-shell structured particles, the induced localized enhanced electromagnetic field due to the strict distance dependence of surface plasmons decays exponentially with increasing distance. The stacked structure only enhances the luminescence of the perovskite nanocrystals in contact with the core-shell structured particles, resulting in limited effectiveness. In contrast, this application directly mixes core-shell structured particles with perovskite material as the luminescent layer, with the perovskite located in the "hotspot region" formed between the core-shell structured particles (see reference). Figure 4 All perovskite materials are located in the plasmon-enhanced region, which can maximize the luminescence performance of perovskite nanocrystals.

[0074] Furthermore, the surface plasmon resonance peak of the silica-coated metal core described in this application coincides with the emission peak of the perovskite material. This allows the light emitted by the perovskite material to resonate and excite the surface plasmon properties of the silica-coated gold-silver alloy. The localized electromagnetic field induced by the surface plasmons, in turn, enhances the luminescence performance of the perovskite material. Compared to a stacked structure consisting of a perovskite luminescent layer and core-shell structured particles, where the layers are stacked at the upper and lower interfaces, the light emitted by the perovskite material can only excite the gold-silver alloy coated in the shell layer that is in contact with the perovskite, resulting in limited enhancement of the localized electromagnetic field induced by the surface plasmons. In contrast, the thin film of this application includes perovskite material and core-shell structured particles doped within the perovskite material. In the mixed contact mode, the light emitted by the perovskite material can excite each metal particle coated in the shell layer. Thus, the induced localized electromagnetic field can completely cover the perovskite material.

[0075] Fourthly, please refer to Figure 3 This application also provides a light-emitting device 100, which includes an anode 10, a light-emitting layer 20, and a cathode 30 stacked sequentially. The light-emitting layer 20 includes the composite material described above.

[0076] The light-emitting layer 20 of the light-emitting device 100 in this embodiment includes the composite material described above. Please refer to... Figures 4-5 Compared to the stacked structure formed by perovskite luminescent layers and core-shell structured particles, the induced localized enhanced electromagnetic field due to the strict distance dependence of surface plasmons decays exponentially with increasing distance. The stacked structure only enhances the luminescence of the perovskite nanocrystals in contact with the core-shell structured particles, resulting in limited effectiveness. In contrast, this application directly mixes core-shell structured particles with perovskite material as the luminescent layer, with the perovskite located in the "hotspot region" formed between the core-shell structured particles (see reference). Figure 4 All perovskite materials are located in the plasmon-enhanced region, which can maximize the luminescence performance of perovskite nanocrystals.

[0077] In some embodiments, the light-emitting device 100 further includes a hole transport layer 40 located between the anode 10 and the light-emitting layer 20.

[0078] In some embodiments, the light-emitting device 100 further includes an electron transport layer 50 located between the light-emitting layer 20 and the cathode 30.

[0079] In some embodiments, the light-emitting device 100 further includes a hole injection layer 60 located between the anode 10 and the hole transport layer 40.

[0080] The anode 10 and the cathode 30 are electrodes known in the art for use in light-emitting devices. For example, they can be, independently, but not limited to, doped metal oxide electrodes, composite electrodes, graphene electrodes, carbon nanotube electrodes, elemental metal electrodes, or alloy electrodes. The material of the doped metal oxide electrode can be, but not limited to, one or more of indium-doped tin oxide (ITO), fluorine-doped tin oxide (FTO), antimony-doped tin oxide (ATO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), indium-doped zinc oxide (IZO), magnesium-doped zinc oxide (MZO), aluminum-doped magnesium oxide (AMO), and cadmium-doped zinc oxide. The composite electrode is an electrode formed by stacking two or more layers of conductive materials, such as 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, Ca / Al, LiF / Ca, LiF / Al, BaF2 / Al, CsF / Al, CaCO3 / Al, BaF2 / Ca / Al, etc., where " / " indicates a stacked structure. For example, AZO / Ag / AZO represents a composite electrode comprising sequentially stacked AZO, Ag, and AZO layers. The material of the elemental metal electrode may include, but is not limited to, one or more of Ag, Ni, Pt, Au, Ir, Cu, Mo, Al, Ca, Mg, and Ba. The alloy electrodes include, but are not limited to, Au:Mg alloy electrodes and Ag:Mg alloy electrodes.

[0081] The hole transport layer 40 can be made of materials known in the art for hole transport layers, such as, but not limited to, 4,4'-N,N'-dicarbazolyl-biphenyl (CBP), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4”-diamine (α-NPD), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TPD), poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)biphenylamine) (Poly-TPD), N,N'-bis... (3-Methylphenyl)-N,N'-bis(phenyl)-spiro(spiro-TPD), N,N'-bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine (DNTPD), 4,4',4'-tris(N-carbazolyl)-triphenylamine (TCTA), 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine (m-MTDATA), poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))] (TFB), poly(N-vinylcarbazole) (PVK) and its derivatives, N,N'-bis(1-naphthyl)-N,N'-diphenyl -1,1'-Biphenyl-4-4'-diamine (NPB), SpiroNPB, Poly(phenylenevinylene) (PPV), Poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), Poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene] (MOMO-PPV), 2,2',7,7'-Tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (spiro-omeTAD), 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] (TAPC), 1,3-Di(carbazole-9-yl)benzene (MCP) The following are included: polyaniline, polypyrrole, poly(p-)phenylenevinylene, aromatic tertiary amine, polynuclear aromatic tertiary amine, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compounds, N,N,N',N'-tetraarylbenzidine, PEDOT:PSS and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, doped graphene, undoped graphene, C60, doped or undoped NiO, doped or undoped MoO3, doped or undoped WO3, doped or undoped V2O5, doped or undoped p-type gallium nitride, doped or undoped CrO3, and doped or undoped CuO.

[0082] The material of the electron transport layer 50 is a material known in the art for electron transport layers, and may be selected from, but is not limited to, one or more inorganic and organic electron transport materials. The inorganic electron transport materials include, but are not limited to, one or more of doped metal oxide particles, undoped metal oxide particles, ceramic semiconductor materials, IIB-VIA group semiconductor materials, IIIA-VA group semiconductor materials, and IB-IIIA-VIA group semiconductor materials. The metal oxides in the undoped metal oxide particles include, but are not limited to, one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5. The doped metal oxides include, but are not limited to, one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, and Al2O3. The doping elements in the doped metal oxides include, but are not limited to, one or more of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, Ga, and Sn. For example, the doped metal oxides can be aluminum zinc oxide (AZO), lithium-doped zinc oxide (LZO), magnesium-doped zinc oxide (MZO), tin-doped zinc oxide (Sn-ZnO), etc. The ceramic semiconductor materials include, but are not limited to, barium titanate. The IIB-VIA group semiconductor materials include, but are not limited to, one or more of ZnS, ZnSe, and CdS. The IIIA-VA group semiconductor materials include, but are not limited to, one or more of InP and GaP. The IB-IIIA-VIA group semiconductor materials include, but are not limited to, one or more of CuInS and CuGaS.

[0083] The organic electron transport materials include, but are not limited to, one or more of the following: quinoxaline compounds, imidazole compounds, triazine compounds, fluorene-containing compounds, and hydroxyquinoline compounds.

[0084] The material of the hole injection layer 60 can be any material known in the art for hole injection layers, such as, but not limited to, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzphenanthrene (HAT-CN), PEDOT, PEDOT:PSS, a derivative of PEDOT:PSS doped with s-MoO3 (PEDOT:PSS:s-MoO3), 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine (m-MTDATA), tetracyanoquinone dimethyl ether (F4-TCQN), copper phthalocyanine, nickel oxide, molybdenum oxide, tungsten oxide, vanadium oxide, molybdenum sulfide, tungsten sulfide, and copper oxide.

[0085] It is understood that the light-emitting device 100 may also be provided with some functional layers that are conventionally used in light-emitting devices and help to improve the performance of the light-emitting device, such as electron blocking layer, hole blocking layer, electron injection layer, interface modification layer, etc.

[0086] It is understood that the materials of each layer of the light-emitting device 100 can be adjusted according to the light-emitting requirements of the light-emitting device 100.

[0087] In some embodiments, the light-emitting device 100 further includes a substrate disposed on the side of the anode 10 away from the light-emitting layer 20, or the substrate disposed on the side of the cathode 30 away from the light-emitting layer 20.

[0088] The substrate can be a rigid substrate or a flexible substrate. In some embodiments, the substrate material may include, but is not limited to, one or more of glass, silicon wafer, polycarbonate, polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate, polyamide, and polyethersulfone.

[0089] It is understood that the light-emitting device 100 can be a normally positioned light-emitting device or an inverted light-emitting device. The light-emitting device 100 can be a quantum dot light-emitting device or an organic light-emitting device.

[0090] The light-emitting layer 20 of the light-emitting device 100 includes the quantum dots described in this application, thereby having high luminous efficiency and long lifetime.

[0091] This application also relates to a display device, which includes the light-emitting device 100.

[0092] The display device can be any electronic product with display function, including but not limited to smartphones, tablets, laptops, digital cameras, digital camcorders, smart wearable devices, smart weighing scales, in-vehicle displays, televisions, or e-book readers. Among them, smart wearable devices can be, for example, smart bracelets, smartwatches, virtual reality (VR) headsets, etc.

[0093] The present application will be specifically described below through specific embodiments. These embodiments are only some embodiments of the present application and are not intended to limit the present application. Unless otherwise specified, the raw materials used in the following embodiments are all commercially available products.

[0094] Example 1

[0095] Please see Figure 2 The method for preparing the composite material in this embodiment includes:

[0096] Provide Au 0.5 Ag 0.5A DMSO solution of SiO2 core-shell structured particles was centrifuged, and the supernatant was removed to obtain Au. 0.5 Ag 0.5 @SiO2;

[0097] Au 0.5 Ag 0.5 @SiO2 added to perovskite material CsPbBr 1.5 Cl 1.5 In a DMSO solution, ink is obtained, wherein Au is present in the ink. 0.5 Ag 0.5 The concentration of SiO2 is 2.4 × 10⁻⁶. 9 CsPbBr / mL 1.5 Cl 1.5 The concentration is 4.0 × 10⁻⁶. 12 cells / mL;

[0098] The ink is centrifuged and enriched, then dried to obtain a composite material.

[0099] The composite material in this embodiment includes perovskite material CsPbBr. 1.5 Cl 1.5 and silica-coated metal particles (Au) 0.5 Ag 0.5 @SiO2).

[0100] In the core-shell structured particles, the thickness of the silica shell is 5.4 nm, the particle size of the metal particles is 37 nm, and the molar ratio of gold to silver in the gold-silver alloy is 0.5:0.5.

[0101] Example 2

[0102] This embodiment is basically the same as Embodiment 1, except that in this embodiment, gold is used instead of the gold-silver alloy in Embodiment 1, that is, gold particles coated with silicon dioxide (Au@SiO2).

[0103] Example 3

[0104] This embodiment is basically the same as Embodiment 1, except that in this embodiment, the molar ratio of gold to silver in the gold-silver alloy is 0.75:0.25, that is, the metal particles coated with silicon dioxide (Au) 0.75 Ag 0.25 @SiO2).

[0105] Example 4

[0106] This embodiment is basically the same as Embodiment 1, except that in this embodiment, the molar ratio of gold to silver in the gold-silver alloy is 0.25:0.75, that is, the metal particles coated with silicon dioxide (Au) 0.25 Ag 0.75@SiO2).

[0107] Example 5

[0108] This embodiment is basically the same as Embodiment 1, except that in this embodiment, silver is used instead of the gold-silver alloy in Embodiment 1, that is, silver particles coated with silicon dioxide (Ag@SiO2).

[0109] Example 6

[0110] This embodiment is basically the same as Embodiment 1, except that in this embodiment, the concentration of the silica-coated metal particles is 0.6 × 10⁻⁶. 9 CsPbBr / mL 1.5 Cl 1.5 The concentration is 6.0 × 10⁻⁶. 12 per mL.

[0111] Example 7

[0112] This embodiment is basically the same as Embodiment 1, except that in this embodiment, the concentration of the silicon dioxide-coated metal particles is 4.2 × 10⁻⁶. 9 CsPbBr / mL 1.5 Cl 1.5 The concentration is 2.0 × 10⁻⁶. 12 per mL.

[0113] Example 8

[0114] This embodiment is basically the same as Embodiment 1, except that the particle size of the metal particles in this embodiment is 15nm.

[0115] Example 9

[0116] This embodiment is basically the same as Embodiment 1, except that the particle size of the metal particles in this embodiment is 80nm.

[0117] Example 10

[0118] This embodiment is basically the same as Embodiment 1, except that the thickness of the silicon dioxide shell is 2nm in this embodiment.

[0119] Example 11

[0120] This embodiment is basically the same as Embodiment 1, except that the thickness of the silicon dioxide shell is 6nm in this embodiment.

[0121] Example 12

[0122] This embodiment is basically the same as Embodiment 1, except that in this embodiment, CsPbBr2Cl1 is used instead of CsPbBr in Embodiment 1. 1.5 Cl 1.5.

[0123] Example 13

[0124] This embodiment is basically the same as Embodiment 1, except that in this embodiment, CsPbBr1Cl2 is used instead of CsPbBr in Embodiment 1. 1.5 Cl 1.5 .

[0125] Example 14

[0126] This embodiment is basically the same as Embodiment 1, except that in this embodiment, CsPbBr3 is used instead of CsPbBr in Embodiment 1. 1.5 Cl 1.5 .

[0127] Example 15

[0128] This embodiment is basically the same as Embodiment 1, except that in this embodiment, CsPbCl3 is used instead of CsPbBr in Embodiment 1. 1.5 Cl 1.5 .

[0129] Comparative Example 1

[0130] The preparation method of the material in this comparative example includes:

[0131] Provide perovskite material CsPbBr 1.5 Cl 1.5 The DMSO solution was centrifuged, enriched, and dried to obtain perovskite material.

[0132] The material used in this comparative example is the perovskite material CsPbBr from Example 1. 1.5 Cl 1.5 This excludes the silica-coated metal particles from Example 1.

[0133] Comparative Example 2

[0134] This comparative example is basically the same as Example 1. This comparative example uses metal particles (Au). 0.5 Ag 0.5 Replace the core-shell structured particles Au in Example 1 0.5 Ag 0.5 @SiO2, in other words, the composite material in this comparative example includes the perovskite material CsPbBr 1.5 Cl 1.5 and metal particles (Au) 0.5 Ag 0.5 (Gold-silver alloy). The particle size of the metal particles is 37 nm, and the molar ratio of gold to silver in the metal particles is 0.5:0.5.

[0135] TEM tests were performed on the silica-coated metal particles of Example 1, and the results were obtained. Figure 6 The diagram shows the microstructure of the silica-coated metal particles.

[0136] Luminescence performance testing:

[0137] The photoluminescence properties of the inks from Examples 1-5 and the perovskite material solutions from Comparative Examples 1-2 were tested to obtain the emission wavelength and intensity of the composite materials, and the enhancement factor was calculated. The test results of the emission intensity and enhancement factor are shown in Table 1.

[0138] The photoluminescence properties of the inks from Examples 1-5 and the perovskite material solution from Comparative Example 1 were tested, and the results were obtained. Figure 7 The photoluminescence spectra of the composite material of Example 1 and the perovskite material of Comparative Example 1 are shown in the figure.

[0139] The photoluminescence properties of the metal particles in Examples 1-5 and the perovskite material in Comparative Example 1 were tested, and the results were obtained. Figure 8 The absorption spectra of the metal particles in Examples 1-5 are shown in the comparison diagram with the photoluminescence spectrum of the perovskite material in Comparative Example 1.

[0140] The photoluminescence performance was tested using a fluorescence spectrophotometer, with the following conditions: 365nm laser excitation, excitation unit slit 2.5mm, emission unit slit 2.5mm, and phototube negative high voltage 400V.

[0141] The enhancement factor is calculated as follows: the luminescence intensity of the perovskite nanomaterial after adding silica-coated gold-silver alloy nanoparticles is reduced by the luminescence intensity of the original perovskite material, and then divided by the luminescence intensity of the original perovskite material.

[0142] Table 1:

[0143]

[0144]

[0145] As shown in Table 1:

[0146] Compared to the materials in Comparative Examples 1-2, the composite materials in Examples 1-5 have a higher enhancement factor. It is evident that the composite materials in Examples 1-5 have a higher luminous intensity. This may be because the composite materials in Examples 1-5 include perovskite material and silica-coated metal particles doped in the perovskite material. Introducing a shell coating on the surface of the metal particles can both prevent direct contact between the perovskite material and the metal particles and place the perovskite material within an enhanced photoelectric field, thereby effectively improving the luminous efficiency of the perovskite material and giving the composite material a higher luminous efficiency.

[0147] Depend on Figure 7 As can be seen, compared with the perovskite material of Comparative Example 1, the composite material of this application has a significantly higher luminescence intensity, which can be increased by about 1420 times.

[0148] Depend on Figure 8 It is known that the molar ratio of gold and silver alters the position of the absorption spectral peaks in gold-silver alloy nanoparticles. When the molar ratio of gold and silver is 0.5:0.5, the perovskite material CsPbBr... 1.5 Cl 1.5 The emitted light can resonate and excite the surface plasmon effect of gold-silver alloy nanoparticles, which in turn enhances the photoelectric field induced by the surface plasmons on CsPbBr. 1.5 Cl 1.5 Photoluminescence; when the emission peak of perovskite material is in the range of 410-520 nm, core-shell nanoparticles with the same emission peak as perovskite material can be found by adjusting the molar ratio of gold and silver elements.

[0149] A luminescent thin film I with a thickness of 1 μm was prepared using the composite material from Example 1; the perovskite material CsPbBr from Example 1 was used. 1.5 Cl 1.5 A light-emitting layer with a thickness of 1 μm was prepared, and a layer of silicon dioxide-coated metal particles with a thickness of 74 nm was deposited on the light-emitting layer to obtain composite light-emitting film II.

[0150] Among them, the contact mode between the perovskite material and the silica-coated metal particles in the luminescent thin film I is as follows: Figure 4 The contact mode between the perovskite material and the silica-coated metal particles in the composite luminescent thin film II is described. Figure 5 .Depend on Figure 4 and Figure 5 It is known that the stacking of perovskite materials and silica-coated metal particles only enhances the luminescence of the perovskite nanocrystals in contact with the core-shell structure particles, and its effect is limited. In contrast, this application directly mixes core-shell structure particles with perovskite materials as the luminescent layer, with the perovskite located in the "hotspot region" formed between the core-shell structure particles (see reference). Figure 4 All perovskite materials are located in the plasmon-enhanced region, which can maximize the luminescence performance of perovskite nanocrystals.

[0151] The luminescence intensity of luminescent film I and composite luminescent film II was tested, and the test results are as follows: Figure 9 As shown, using Figure 4 The luminescence intensity of the luminescent film I shown is significantly greater than that of the film shown. Figure 5 The luminescence intensity of the composite luminescent film II shown.

[0152] The technical solutions provided by the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A composite material, characterized in that, Comprising a perovskite material and core-shell structured particles doped in the perovskite material, wherein the core of the core-shell structured particles is a metal particle, and the metal in the metal particle is Au a Ag b , where 0 < a < 1, 0 < b < 1, and a + b = 1; the material of the shell layer of the core-shell structured particles includes silicon dioxide, the perovskite material forms a continuous structure, and the core-shell structured particles are dispersed in the perovskite material; the ratio range of the concentration of the perovskite material to the core-shell structured particles doped in the perovskite material is (4.5 × 10 2 ~ 1.0 × 10 4 ):1; The shell thickness of the core-shell structured particles is 3~6 nm; The absorption peak of the nucleus is in the range of 410~550 nm; The photoluminescence peak of the perovskite material is in the range of 410~550 nm.

2. The composite material as described in claim 1, characterized in that, The average particle size of the nucleus is 15~80 nm.

3. The composite material as described in claim 1, characterized in that, The average particle size of the nucleus is 30~50 nm.

4. The composite material as described in claim 1, characterized in that, The perovskite material is perovskite nanocrystals.

5. The composite material as described in claim 4, characterized in that, The perovskite nanocrystals are spherical or cubic in shape.

6. The composite material as described in claim 4, characterized in that, The perovskite nanocrystals have a particle size of 1~20 nm.

7. The composite material as described in claim 4, characterized in that, The perovskite nanocrystals have a particle size of 3-5 nm.

8. The composite material as described in claim 1, characterized in that, The chemical formula of the perovskite material is CsPbBr. x Cl 3-x , where 0≤x≤3.

9. An ink, characterized in that, Includes the composite material and solvent as described in any one of claims 1 to 8.

10. The ink as described in claim 9, characterized in that, The concentration of perovskite material in the ink is 2.0 × 10⁻⁶. 12 ~ 6.0 × 10 12 pcs / mL; and / or The concentration of the core-shell structured particles in the ink is 0.6 × 10⁻⁶. 9 ~4.2 × 10 9 pcs / mL; and / or The solvents include ethanol, n-hexane, and dimethyl sulfoxide. N , N One or more of dimethylformamide.

11. A thin film, characterized in that, The composite material described in any one of claims 1 to 8.

12. A light-emitting device, characterized in that, Includes the thin film as described in claim 11.

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