Stacked light emitting device

Abstract

This application belongs to the field of display technology and relates to a composite thin film, comprising a first thin film and a second thin film stacked together. The first thin film is made of a quaternary ammonium salt polymer, and the second thin film is made of a heteropolyacid. This application also relates to a method for preparing the composite thin film, a stacked light-emitting device, and a display device. The technical solution provided by this application can form a certain dipole orientation capability within the composite thin film, improving electron injection efficiency.

Description

Technical Field

[0001] This application relates to the field of display technology, and more specifically, to a composite thin film and its preparation method, a stacked light-emitting device, and a display device. Background Technology

[0002] Stacked light-emitting devices (LEDs) are formed by connecting two or more light-emitting units in series, thereby reducing the operating current of the LEDs at the same brightness and thus improving their lifespan. The multiple light-emitting units are usually connected by a charge generation layer. However, when electrons separated from the charge generation layer are injected into the light-emitting units, a high injection barrier is required, resulting in low electron injection efficiency. Summary of the Invention

[0003] This application provides a composite thin film and its preparation method, a stacked light-emitting device, and a display device.

[0004] This application provides a composite film, which adopts the following technical solution:

[0005] A composite film includes a first film and a second film stacked together, wherein the material of the first film includes a quaternary ammonium salt polymer, and the material of the second film includes a heteropoly acid.

[0006] This application provides a method for preparing a composite thin film, which adopts the following technical solution:

[0007] A method for preparing a composite thin film includes the following steps:

[0008] A first solution containing a quaternary ammonium salt polymer is provided, and the first solution is deposited to form a first functional film;

[0009] A second solution containing a heteropoly acid is provided, and the second solution is deposited on the first functional film to form a second functional film, thereby obtaining the composite film.

[0010] This application also provides a stacked light-emitting device, which adopts the following technical solution:

[0011] A stacked light-emitting device includes an anode and a cathode disposed opposite to each other, and at least two layers of light-emitting units stacked between the anode and the cathode;

[0012] The stacked light-emitting device further includes a charge generation layer disposed between two adjacent light-emitting units, wherein the charge generation layer is a composite thin film as described above or prepared by the composite thin film preparation method described above.

[0013] This application provides a display device that adopts the following technical solution:

[0014] A display device comprising, as described above, a stacked light-emitting device.

[0015] Compared with the prior art, the embodiments of this application have the following main advantages:

[0016] The composite film provided in this application achieves mutual attraction between the quaternary ammonium salt cations in the quaternary ammonium salt polymer of the first film and the heteropolyacid anions of the second film due to Coulomb stress. Since the heteropolyacid anions have a large ion size, they are difficult to diffuse to the lower layer. Therefore, the quaternary ammonium salt cations and heteropolyacid anions will form an oriented dipole layer at the interface between the first film and the second film, thereby giving the composite film a large dipole orientation capability and improving the electron injection efficiency of the composite film. Attached Figure Description

[0017] To more clearly illustrate the solution 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 some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of the composite film according to an embodiment of this application;

[0019] Figure 2 This is a flowchart of a method for preparing a composite thin film according to an embodiment of this application;

[0020] Figure 3 This is a schematic diagram of the structure of the stacked light-emitting device according to an embodiment of this application.

[0021] Figure label:

[0022] 1. First thin film; 2. Second thin film; 100. Anode; 200. First light-emitting unit; 201. First hole injection layer; 202. First hole transport layer; 203. First light-emitting layer; 204. First electron transport layer; 300. Charge generation layer; 400. Second light-emitting unit; 401. Second hole injection layer; 402. Second hole transport layer; 403. Second light-emitting layer; 404. Second electron transport layer; 500. Cathode. Detailed Implementation

[0023] 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 application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0024] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0025] Organic light-emitting diodes (OLEDs) based on solution-based technology have significant advantages in large-area and diverse form factor terminal displays due to their suitability for low-cost manufacturing processes. In their design, OLEDs typically combine two or more OLEDs in series to form a stacked OLED, which reduces the operating current at the same brightness, thereby extending the device's lifespan. This is a crucial direction for improving the lifespan of current OLEDs.

[0026] Typically, the electrodes connecting two adjacent light-emitting units in a stacked light-emitting device are replaced by a charge generation layer. When the stacked light-emitting device is working, the charge generation layer converts the absorbed photons into free charge carriers (electrons and holes) and can separate these charges so that they can move towards the electrodes under the action of an electric field, thereby generating current and thus reducing the operating current of the device.

[0027] Because there is a large energy difference (usually greater than or equal to 2 eV) between the charge generation layer and the electron transport layer, a very high electron injection barrier is formed. Furthermore, the electron transport layer cannot generate enough free carriers to transfer to the charge generation layer, making it difficult to form a sufficiently large interfacial potential difference to offset the energy difference. As a result, the carrier injection efficiency of the charge generation layer is low.

[0028] Based on the background technology described above, embodiments of this application provide a composite thin film. By constructing an oriented dipole layer within the composite thin film, the composite thin film gains a greater dipole orientation capability, thereby improving the electron injection efficiency of the composite thin film.

[0029] Please see Figure 1As shown in the figure, this application provides a composite film, including a first film and a second film stacked together.

[0030] In some embodiments, the material of the first film 1 is selected from quaternary ammonium salt polymers. In this embodiment, the quaternary ammonium salt polymer comprises quaternary ammonium salt cations and halogen anions.

[0031] The material of the second film 2 is selected from heteropoly acids. In this embodiment, the absolute value of the LUMO of the second film 2 is greater than or equal to 4 eV. The heteropoly acid is a type of acid containing multiple elements, usually a compound synthesized by transition metal ions and oxyacid molecules through oxygen bridging bonds. It can provide protons (hydrogen cations) to the halide anions of the quaternary ammonium salt polymer so as to form hydrogen halides during the formation of the composite film and vaporize them during the annealing stage, thus avoiding the generation of impurity precipitates at the interface between the first film and the second film, which would affect the performance of the composite film.

[0032] The composite film provided in this application achieves mutual attraction between the quaternary ammonium cations in the quaternary ammonium polymer of the first film 1 and the heteropolyacid anions of the second film 2 due to Coulomb stress. Because the heteropolyacid anions have a large ion size, they are difficult to diffuse to the lower layer. Therefore, the quaternary ammonium cations and heteropolyacid anions form an oriented dipole layer at the interface between the first film 1 and the second film 2, thereby giving the composite film a greater dipole orientation capability and improving the electron injection efficiency of the composite film. Simultaneously, since the second film 2 is made of a heteropolyacid material, it has a large electron affinity (LUMO absolute value greater than or equal to 4 eV), which can improve the hole injection efficiency of the composite film.

[0033] In some embodiments, the monomers of the quaternary ammonium salt polymer have the structure shown in Formula I, and the quaternary ammonium salt polymer is formed by homopolymerization of the same monomer or copolymerization of different monomers:

[0034]

[0035] R1, R2, and R3 are each independently selected from C1-C20 hydrocarbon groups and C1-C20 hydroxyl groups that are unsubstituted or substituted by amino, halogen, hydroxyl, carboxyl, ester, acyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, hydrocarbon, or hydroxyl groups; L1 and L2 are each independently selected from C1-C20 alkylene groups and C1-C20 alkylene groups that are unsubstituted or substituted by amino, halogen, hydroxyl, carboxyl, ester, acyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, hydrocarbon, or hydroxyl groups. Optionally, L1 or L2 can be connected to R2 or R3 respectively to form pyrrolidine quaternary ammonium salts or piperazine quaternary ammonium salts; X is selected from one or more of Cl, Br, and I.

[0036] In this embodiment, a first thin film 1 is prepared using a quaternary ammonium salt polymer. During film formation, the halogen anions in the quaternary ammonium salt polymer can react with the heteropolyacid cations in the second thin film 2 to generate volatile hydrogen halides. This promotes pairing between the quaternary ammonium salt cations in the first thin film 1 and the heteropolyacid anions in the second thin film 2, thereby constructing a larger oriented dipole layer at the interface between the first thin film 1 and the second thin film 2. This achieves a certain dipole orientation capability within the composite film, improving the electron injection efficiency of the composite film. Simultaneously, the cations in the quaternary ammonium salt polymer are in polymer form, which can suppress their migration under an electric field and improve the resistance of the first thin film 1 to solvent erosion.

[0037] In this embodiment, there is no connection between L1, L2, R1, and R2, and the cation of the quaternary ammonium salt polymer is a quaternary ammonium salt cation.

[0038] Furthermore, L1 or L2 can be connected with R2 or R3 respectively to form a five-membered nitrogen-containing heterocycle to form a pyrrolidine quaternary ammonium salt cation; or, L1 or L2 can be connected with R2 or R3 respectively to form a six-membered nitrogen-containing heterocycle to form a piperazine quaternary ammonium salt cation.

[0039] In this embodiment, L1 or L2 is connected to R2 or R3 to form a ring, thereby protecting the structure of the quaternary ammonium salt cation and improving the structural stability of the quaternary ammonium salt polymer.

[0040] In some embodiments, the cation in the quaternary ammonium polymer is selected from one or more of the following structural formulas a to d, wherein m in formulas a and b is selected from integers not greater than 6; R4 and R5 in formula c are each independently selected from unsubstituted or substituted C1-C10 hydrocarbon groups or C1-C10 alkyl ...

[0041]

[0042] In some embodiments, when the cation of the quaternary ammonium polymer is a quaternary ammonium cation, the quaternary ammonium cation is selected from one or more of the following structural formulas:

[0043]

[0044]

[0045] In some embodiments, when the cation in the quaternary ammonium salt polymer is selected from pyrrolidine quaternary ammonium salt cations, the pyrrolidine quaternary ammonium salt cations are selected from one or more of the following structures:

[0046]

[0047] In some embodiments, when the cation in the quaternary ammonium salt polymer is selected from piperazine quaternary ammonium salt cations, the piperazine quaternary ammonium salt cation is selected from one or more of the following structures:

[0048]

[0049] In this embodiment, the mass-average molecular weight (Mw) of the quaternary ammonium salt polymer is ≥100,000. Since a larger mass-average molecular weight can help improve the composite film's resistance to solvent damage, the maximum value of the mass-average molecular weight is not limited here. Specifically, the mass-average molecular weight of the quaternary ammonium salt polymer can be set to any one of 100,000, 180,000, 200,000, 220,000, and 240,000, or a range formed between any two of these values.

[0050] In some embodiments, the heteropolyacid includes at least one compound having the following general formula:

[0051] H n A x M y O z ;

[0052] Wherein, A is selected from one or more of Cr, Fe, Ni, Al, P, Si, B, Ga, As, Sb, and Bi; M is selected from transition metals of group VB or group VI B, optionally, M is selected from one or more of Mo, W, V, Nb, and Ta, and A and M are different elements; x, y, and z satisfy: x is 1, y is 12, and z is 40; or x is 2, y is 18, and z is 62; or x is 1, y is 6, and z is 24; or x is 1, y is 9, and z is 32; or x is 1, y is 12, and z is 42; n is any positive number that satisfies the charge balance within the compound.

[0053] Optionally, the heteropolyacid is selected from H3PMo. 12 O 40 H6PMo 12 O 42 H6P2Mo 18 O 62 H3PW 12 O 40 H6P2W 18 O62 H4PV 12 O 40 H3CrMo6O 24 H6Si Mo 12 O 40 H3CrMo6O 24 H6N i Mo9O 32 H3FeMo 12 O 40 One or more of them.

[0054] In some embodiments, the thickness of the first film 1 is 1 nm to 50 nm, preferably 10 nm to 20 nm. Specifically, the thickness of the first film 1 can be set to any one of 1 nm, 2 nm, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, and 50 nm, or a range formed between any two of these values.

[0055] In some embodiments, the thickness of the second thin film 2 is 1 nm to 50 nm, preferably 10 nm to 20 nm. Specifically, the thickness of the second thin film 2 can be set to any one of 1 nm, 2 nm, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, and 50 nm, or a range formed between any two of these values.

[0056] Based on the composite film described above, this application also provides a method for preparing the composite film.

[0057] Please see Figure 2 As shown, the method for preparing the composite thin film provided in this application includes the following steps:

[0058] Step S100: A first solution containing a quaternary ammonium salt polymer is provided, and the first solution is deposited to form a first thin film.

[0059] In this embodiment, the quaternary ammonium polymer comprises quaternary ammonium cations and halogen anions.

[0060] Step S200: A second solution containing a heteropoly acid is provided, and the second solution is deposited on the first film to form a second film, thereby obtaining the composite film.

[0061] In this embodiment, the composite film is prepared by sequentially depositing a first film and a second film using a solution method. The preparation method is simple and has high preparation efficiency. At the same time, the composite film prepared by the method of this application has good carrier injection efficiency.

[0062] In some embodiments, the deposition of the first solution to form a first thin film in step S100 is specifically achieved through the following steps:

[0063] The first solution is used to form a first liquid film, and then subjected to a first annealing treatment to obtain the first thin film.

[0064] In this embodiment, the temperature range of the first annealing treatment is 100℃~150℃. Specifically, the temperature of the first annealing treatment can be set to any one of 100℃, 110℃, 120℃, 130℃, 140℃, and 150℃, or a range formed between any two of these values.

[0065] The duration of the first annealing process is 5 min to 15 min. Specifically, the duration of the first annealing process is any one of 5 min, 10 min, and 15 min, or a range between any two of these values.

[0066] In some embodiments, the first solution in step S100 is prepared by the following steps:

[0067] A third solution containing tertiary amine polymers and a fourth solution containing haloalkanes are provided;

[0068] The first solution is obtained by mixing the third solution and the fourth solution according to a set mass ratio.

[0069] In this embodiment, the set mass ratio is 10:1 to 1:2. Specifically, the set mass ratio between the third solution and the fourth solution can be set to any one of 10:1, 5:1, 2:1, 1:1, 1:2 or a range formed between any two values.

[0070] In this embodiment, by setting a suitable mass ratio of the third solution to the fourth solution, the tertiary amine group in the tertiary amine polymer reacts sufficiently with the halogen atom in the haloalkane, thereby facilitating the formation of the quaternary ammonium salt polymer.

[0071] In this embodiment, after mixing the third solution and the fourth solution according to a set mass ratio, the following steps are also included:

[0072] The mixture of the third solution and the fourth solution is subjected to continuous stirring. In this embodiment, the stirring duration is 10 min to 30 min. Specifically, the stirring duration can be set to any one of 10 min, 20 min, and 30 min, or a range between any two of these values.

[0073] In some embodiments, the tertiary amine polymer is selected from one or more of the following structural formulas e to h;

[0074] In formula g, R8 is selected from C1 to C10 hydrocarbon groups and C1 to C10 hydroxyl groups that are unsubstituted or substituted by amino, halogen, hydroxyl, carboxyl, ester, acyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, hydrocarbon, or hydroxyl groups.

[0075] R9 in formula h is selected from C1 to C10 hydrocarbon groups and C1 to C10 alkyl groups that are unsubstituted or substituted by amino, halogen, hydroxyl, carboxyl, ester, acyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, hydrocarbon, or alkyloxy groups.

[0076] The mass-average molecular weight (Mv) of the tertiary amine polymer is ≥10000.

[0077]

[0078]

[0079] In some embodiments, when the cation of the quaternary ammonium polymer is a quaternary ammonium cation, the tertiary amine polymer used may be selected from one or more of the following structural formulas:

[0080]

[0081] In some embodiments, when the cation in the quaternary ammonium salt polymer is a pyrrolidine quaternary ammonium salt cation, the tertiary amine polymer used may be selected from the following structural formulas:

[0082]

[0083] In some embodiments, when the cation in the quaternary ammonium salt polymer is a piperazine quaternary ammonium salt cation, the tertiary amine polymer used may be selected from the following structural formulas:

[0084]

[0085] In some embodiments, the haloalkane is selected from one or more of dibromopentane, dibromohexane, dibromoheptane, and dibromooctane.

[0086] In some embodiments, step S200, depositing the second solution on the first film to form a second film, specifically includes the following steps:

[0087] The second solution is applied to the first film to form a second liquid film, and then subjected to a second annealing treatment to obtain the second film.

[0088] In this embodiment, the temperature range of the second annealing treatment is 50℃~100℃. Specifically, the temperature of the first annealing treatment can be set to any one of 50℃, 60℃, 70℃, 80℃, 90℃, and 100℃, or a range formed between any two of these values.

[0089] The duration of the second annealing process is 5 min to 15 min. Specifically, the duration of the second annealing process is any one of 5 min, 10 min, and 15 min, or a range between any two of these values.

[0090] In this embodiment of the application, when a second liquid film is formed on the first thin film by a second solution, the acidic properties of the heteropolyacid in the second solution (i.e., hydrogen cations) react with the halogen anions in the first thin film to form volatile hydrogen halides. The formation of hydrogen halides is activated during the second annealing process, which accelerates or promotes the chemical reaction, thereby enabling the quaternary ammonium salt cations in the lower layer and the heteropolyacid anions in the upper layer to construct a larger directional dipole layer.

[0091] Based on the composite thin film and its preparation method as described above, this application also provides a stacked light-emitting device.

[0092] Please see Figure 3 As shown, this application provides a light-emitting device, including an anode 100 and a cathode 500 disposed opposite to each other, and at least two layers of light-emitting units stacked between the anode 100 and the cathode 500;

[0093] Furthermore, the stacked light-emitting device also includes a charge-generating layer 300 disposed between two adjacent light-emitting units, wherein the charge-generating layer 300 is a composite thin film as described above or prepared by the composite thin film preparation method described above.

[0094] In this embodiment, the stacked light-emitting device includes two light-emitting units, namely a first light-emitting unit 200 disposed near the anode 100 and a second light-emitting unit 400 disposed near the cathode 500, and the charge generating layer 300 is located between the first light-emitting unit 200 and the second light-emitting unit 400.

[0095] In this embodiment, the stacked light-emitting device is an upright stacked light-emitting device. The first light-emitting unit 200 includes a first hole injection layer 201, a first hole transport layer 202, a first light-emitting layer 203, and a first electron transport layer 204 stacked sequentially from bottom to top. The second light-emitting unit 400 includes a second hole injection layer 401, a second hole transport layer 402, a second light-emitting layer 403, and a second electron transport layer 404 stacked sequentially from bottom to top. The charge generation layer 300 is located between the first electron transport layer 204 and the second hole injection layer 401.

[0096] In some embodiments, the charge generation layer 300 includes a first thin film 1 and a second thin film 2 stacked together. The first thin film 1 is located on the side closer to the anode 100, and the second thin film 2 is located on the side closer to the cathode 500. In this embodiment, the first thin film 1 is in contact with the first electron transport layer 204, and the second thin film 2 is in contact with the second hole injection layer 401.

[0097] In this embodiment, the surface potential difference between the first thin film 1 and the second thin film 2 is greater than or equal to 0.5V.

[0098] In some embodiments, the surface potential difference is characterized by testing the surface potential of the thin film using a scanning Kelvin probe microscope. Specifically, an F8BT material is placed on the base to form a background sample, and the composite thin film is formed on the background sample as a test sample. The surface potentials of the background sample and the test sample are tested, and their surface potential difference is calculated (wherein, surface potential difference = test sample potential - background sample potential).

[0099] In this embodiment, by forming a potential difference greater than or equal to 0.5V between the first thin film 1 and the second thin film 2, a directional dipole moment is formed at the interface between the first thin film 1 and the second thin film 2, which is parallel to the normal of the interface or forms a set angle with the normal of the interface, thereby realizing the construction of a directional dipole layer at the interface between the first thin film 1 and the second thin film 2.

[0100] In some embodiments, the qualitative relationship between surface potential difference and interface dipole moment can be described by the following formula:

[0101]

[0102] Where ΔV is the surface potential difference. It is the vector of the interface dipole moment. It is its magnitude, θ is the angle formed between the dipole moment and the normal of the interface, ε is the dielectric constant of the material, and A is the area of ​​the interface.

[0103] Therefore, based on the above formula, it can be seen that when the dielectric constant of the material and the area of ​​the interface are constant, the surface potential difference and the interface dipole moment are linearly related. That is, the larger the surface potential difference, the larger the interface dipole moment. Therefore, the larger the surface potential difference formed between the first thin film 1 and the second thin film 2, the larger the directional dipole moment formed, thereby improving the electron transport efficiency of the composite thin film.

[0104] The stacked light-emitting device provided in this application embodiment uses the composite thin film as described above as the charge generating layer 300. By combining the quaternary ammonium salt cations in the first thin film 1 with the heteropolyacid anions in the second thin film 2, a directional dipole layer is constructed at the interface between the first thin film 1 and the second thin film 2. This gives the charge generating layer 300 a large dipole orientation capability, thereby increasing the interfacial dipole moment between the first thin film 1 and the first electron transport layer 204. The large electric field of the directional dipole layer within the charge generating layer 300 assists in directing the charge generating layer 300 toward the first light-emitting unit 2. Electron injection in the 00 direction improves the electron injection efficiency of the charge generation layer 300. Meanwhile, since the second thin film 2 is made of heteropolyacid material, it has a large electron affinity (LUMO absolute value greater than or equal to 4eV), which can be used as an electrode to inject holes into the second light-emitting unit 400, thereby improving the hole injection efficiency of the composite film. In addition, since the quaternary ammonium salt cation in the first thin film 1 and the heteropolyacid anion in the second thin film 2 have large molecular volumes, they are difficult to migrate under an electric field and will not affect the response characteristics of the stacked light-emitting device.

[0105] In some embodiments, the stacked light-emitting device may further include more than two light-emitting units, wherein one light-emitting unit includes a hole functional layer, a light-emitting layer and an electron functional layer stacked together, wherein the hole functional layer is located between the light-emitting layer and the anode 100, and the electron functional layer is located between the light-emitting layer and the cathode 500. In this embodiment, the electron functional layer includes an electron transport layer.

[0106] In some embodiments, the materials of the anode 100 and / or cathode 500 include one or more of metals, carbon materials, and metal oxides. The metals include one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg. The carbon materials include one or more of graphite, carbon nanotubes, graphene, and carbon fibers. The metal oxides include doped or undoped metal oxides, including one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, and AMO, or composite electrodes consisting of metal sandwiched between doped or undoped transparent metal oxides. The composite electrodes include one or more of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO2 / Ag / TiO2, and TiO2 / Al / TiO2.

[0107] The materials of the first hole injection layer 201 and / or the second hole injection layer 401 and / or the first hole transport layer 202 and / or the second hole transport layer 402 include one or more of TFB, CuPc, PVK, Poly-TPD, PFB, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, polyaniline, transition metal oxides, transition metal sulfides, transition metal tin compounds, doped graphene, undoped graphene, and C60.

[0108] The first light-emitting layer 203 and / or the second light-emitting layer 403 are quantum dot light-emitting layers or organic light-emitting layers; wherein, the material of the quantum dot light-emitting layer includes one or more of single-structure quantum dots and core-shell structure quantum dots, the material of the single-structure quantum dots, the core material of the core-shell structure quantum dots, and the shell material of the core-shell structure quantum dots are respectively selected from one or more of group II-IV I compounds, group IV-VI compounds, group II IV compounds, and group III-VI compounds, and the shell of the core-shell structure quantum dots includes one or more layers; wherein, group III-IV Group I compounds include, but are not limited to, one or more of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe. Group V-VI compounds include, but are not limited to, one or more of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe. Group II-IV compounds include, but are not limited to, GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaA One or more of the following groups: I PAs, GaAl PSb, Ga InNP, Ga InNAs, Ga InNSb, Ga InPAs, Ga InPSb, InAl NP, InAl NAs, InAl NSb, InAl PAs, and InAl PSb; and one or more of the following groups: III-VI compounds, including but not limited to one or more of Cu InS2, Cu InSe2, and Ag InS2.The organic light-emitting layer is made of one or more of the following materials: 4,4'-bis(N-carbazole)-1,1'-biphenyl:tris[2-(p-tolyl)pyridine-C2,N)iridium(III), 4,4',4”-tris(carbazole-9-yl)triphenylamine:tris[2-(p-tolyl)pyridine-C2,N)iridium, diaromatic anthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPX fluorescent materials, TBRb fluorescent materials and DBP fluorescent materials, polyacetylene and its derivatives, poly(p-phenylene) and its derivatives, polythiophene and its derivatives, and polyfluorene and its derivatives.

[0109] The first electron transport layer 204 and / or the second electron transport layer 404 comprise inorganic or organic materials; wherein the inorganic material is selected from one or more of the following: doped or undoped zinc oxide, barium oxide, aluminum oxide, nickel oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, zinc aluminum oxide, zinc manganese oxide, zinc tin oxide, zinc lithium oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc tin sulfide, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, and barium titanate; and the doped elements include aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, and zirconium. The organic material is selected from one or more of cerium, gadolinium, and quinoxaline compounds, imidazole compounds, triazine compounds, fluorene compounds, hydroxyquinoline compounds, phosphooxide compounds, pyridine compounds, quinoline compounds, isoquinoline compounds, benzimidazole compounds, pyrazine compounds, acridine compounds, pyrazole compounds, pyrimidine compounds, pyridazine compounds, imidazole compounds, phenanthroline compounds, isoindole compounds, oxazole compounds, isoxazole compounds, phosphorus oxide compounds, triarylborane compounds, and tetraarylsilane compounds.

[0110] This application also provides a display device, which includes the above-described stacked light-emitting device.

[0111] 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.

[0112] The present application will be specifically described below through specific embodiments. The following embodiments are only some embodiments of the present application and are not intended to limit the present application.

[0113] Composite Thin Film Example 1

[0114] Step (1): Provide a substrate;

[0115] Step (2): The first solution is spin-coated onto the substrate and annealed at 100°C for 5 min to form a first thin film with a thickness of 3 nm. The quaternary ammonium salt polymer in the first solution is selected from the following structures:

[0116]

[0117] Among them, the mass-average molecular weight of the quaternary ammonium salt polymer is Mw = 180,000, and the halogen is selected from bromine;

[0118] Step (3): Spin-coating H3PMo onto the first thin film 12 O 40 A solution of ethylene glycol diethyl ether containing phosphomolybdic acid was prepared and annealed at 60°C for 5 min to form a second film with a thickness of 2 nm, thus obtaining a composite film.

[0119] Composite film Example 2

[0120] The difference between this embodiment and the composite film embodiment 1 is as follows:

[0121] The quaternary ammonium salt polymer in step (2) is selected from the following structures:

[0122]

[0123] The quaternary ammonium salt polymer has a mass-average molecular weight Mw of 200,000, and the halogen is selected from bromine.

[0124] Composite film Example 3

[0125] The difference between this embodiment and the composite film embodiment 1 is as follows:

[0126] The quaternary ammonium salt polymer in step (2) is selected from the following structures:

[0127]

[0128] The quaternary ammonium salt polymer has a mass-average molecular weight Mw of 220,000, and the halogen is selected from bromine.

[0129] Composite film Example 4

[0130] The difference between this embodiment and the composite film embodiment 1 is as follows:

[0131] The quaternary ammonium salt polymer in step (2) is selected from the following structures:

[0132]

[0133] The quaternary ammonium salt polymer has a mass-average molecular weight Mw of 240,000, and the halogen is selected from bromine.

[0134] Composite film Example 5

[0135] The difference between this embodiment and the composite film embodiment 2 is as follows:

[0136] Step (3): Spin-coating H3PW onto the first film 12 O 40 A 2 nm thick second film was formed by annealing a solution of phosphotungstic acid in ethylene glycol diethyl ether at 60 °C for 5 min, thus obtaining a composite film.

[0137] Composite film Example 6

[0138] The difference between this embodiment and the composite film embodiment 2 is as follows:

[0139] Step (3): Spin-coating H6P2Mo onto the first thin film 18 O 62 A solution of ethylene glycol diethyl ether containing phosphomolybdic acid was prepared and annealed at 60°C for 5 min to form a second film with a thickness of 2 nm, thus obtaining a composite film.

[0140] Composite film Example 7

[0141] The difference between this embodiment and the composite film embodiment 2 is that the mass-average molecular weight of the quaternary ammonium salt polymer in step (2) is Mw = 100000.

[0142] Composite film comparative example 1

[0143] The difference between this comparative example and Example 1 of the composite film is:

[0144] Step (3): Spin-coat the first film with ethylene glycol diethyl ether solution and anneal at 60°C for 5 min to form a second film, resulting in a 3 nm thick composite film.

[0145] Composite film comparative example 2

[0146] The difference between this comparative example and Example 1 of the composite film is that step (2.1) is included between step (2) and step (3):

[0147] Step (2.1) involves spin-coating a 2 nm thick polymethyl benzoate layer onto the first film as a barrier layer to eliminate the interaction between the combined layers.

[0148] Test Result Analysis

[0149] The background sample is prepared using the following steps:

[0150] Step (1). Provide an ITO anode substrate, clean the ITO anode substrate, and then perform UV treatment;

[0151] Step (2): Spin-coat a 20 nm thick layer of F8BT onto the ITO anode substrate and anneal it at 150 °C for 30 min to obtain the background sample.

[0152] The composite films prepared in Examples 1-7, Comparative Examples 1 and 2 were used as test samples and formed on the background sample. The surface potential of the film was characterized by scanning Kelvin probe microscopy. The dipole orientation ability of the composite film was evaluated by the surface potential difference between the test background sample and the test sample (where surface potential difference = test sample potential - background sample potential). The results are shown in Table 1 below.

[0153] Surface potential difference (V) Composite Thin Film Example 1 1.47 Composite film Example 2 1.25 Composite film Example 3 1.36 Composite film Example 4 1.35 Composite film Example 5 1.44 Composite film Example 6 1.49 Composite film Example 7 1.32 Composite film comparative example 1 0 Composite film comparative example 2 0

[0154] Table 1

[0155] Table 1 shows that by comparing the experimental data of composite film examples 1-7 with those of composite film comparative examples 1 and 2, it can be seen that the composite film provided in this application can form a potential difference with the background sample, thus exhibiting good dipole orientation capability. However, since composite film comparative example 1 lacks a second film and composite film comparative example 2 has a barrier layer between the first and second films, the composite films prepared by composite film comparative examples 1 and 2 cannot separate the cations and anions in the quaternary ammonium salt polymer, thus failing to construct an oriented dipole layer and lacking dipole orientation capability. Therefore, the detected potential difference is 0.

[0156] By comparing the experimental data of composite films in Examples 1 to 7, it can be seen that different orientation capabilities are formed between different quaternary ammonium salt polymers and heteropoly acids, and the difference in mass-average molecular weight leads to the difference in the distance between the positive and negative charge centers, thus forming different surface potential differences and thus different dipole orientation capabilities.

[0157] Example 1 of a multilayer light-emitting device

[0158] Step (1): Provide an ITO anode substrate, clean the ITO anode substrate, and then treat it under UV conditions for 15 min to increase its work function and wettability.

[0159] Step (2): PEDOT:PSS is spin-coated onto the ITO anode substrate and baked at 150°C for 20 min in an air atmosphere to form a first hole injection layer with a thickness of 30 nm.

[0160] Step (3): Spin-coat TFB onto the first hole injection layer, and then bake at 180°C for 60 min in a nitrogen atmosphere to form a 20 nm thick first hole transport layer.

[0161] Step 4: Spin-coat F8BT onto the first hole transport layer and bake at 130°C for 10 min to form a 60nm thick first light-emitting layer;

[0162] Step 5: Spin-coat TV-TmPY onto the first light-emitting layer and anneal at 150°C for 30 min to form a 20 nm first electron transport layer;

[0163] Step 6: A 30 nm thick charge generation layer is formed on the first electron transport layer using the preparation method of the composite thin film in Example 1. The charge generation layer includes a 20 nm thick first thin film and a 10 nm thick second thin film stacked together.

[0164] Step 7: Spin-coat Poly-TPD:TrTPFB (TrTPFB mass ratio 10%) onto the charge generation layer and bake at 150°C in air for 20 min to form a second hole injection layer with a thickness of 30 nm.

[0165] Step 8: Spin-coat TFB onto the second hole injection layer, and then bake at 180°C for 60 min in a nitrogen atmosphere to form a 30 nm thick second hole transport layer.

[0166] Step 9: Spin-coat F8BT onto the second hole transport layer and bake at 130°C for 15 min to form an 80 nm thick second light-emitting layer;

[0167] Step 10: LiF is deposited onto the substrate by vapor deposition to form a second light-emitting layer, forming a 10nm thick second electron transport layer;

[0168] Step 11: Al is deposited onto the second electron transport layer by vapor deposition to form a cathode with a wavelength of 100 nm.

[0169] Example 2 of stacked light-emitting device

[0170] The difference between this embodiment and the stacked light-emitting device embodiment 1 is that, in step 6, a 30nm thick charge generation layer is formed on the first electron transport layer using the preparation method of the upper composite thin film embodiment 2.

[0171] Example 3 of stacked light-emitting devices

[0172] The difference between this embodiment and the stacked light-emitting device embodiment 1 is that, in step 6, a 30 nm thick charge generation layer is formed on the first electron transport layer using the preparation method of the upper composite thin film embodiment 3.

[0173] Example 4 of stacked light-emitting device

[0174] The difference between this embodiment and the stacked light-emitting device embodiment 1 is that, in step 6, a 30 nm thick charge generation layer is formed on the first electron transport layer using the preparation method of the upper composite thin film embodiment 4.

[0175] Example 5 of a stacked light-emitting device

[0176] The difference between this embodiment and the stacked light-emitting device embodiment 1 is that, in step 6, a 30 nm thick charge generation layer is formed on the first electron transport layer using the preparation method of the upper composite thin film embodiment 5.

[0177] Example 6 of stacked light-emitting device

[0178] The difference between this embodiment and the stacked light-emitting device embodiment 1 is that, in step 6, a 30 nm thick charge generation layer is formed on the first electron transport layer using the preparation method of the upper composite thin film embodiment 6.

[0179] Example 7 of a multilayer light-emitting device

[0180] The difference between this embodiment and the stacked light-emitting device embodiment 1 is that, in step 6, a 30 nm thick charge generation layer is formed on the first electron transport layer using the preparation method of the upper composite thin film embodiment 7.

[0181] Comparative Example 1 of Multilayer Light Emitting Devices

[0182] The difference between this comparative example and Example 1 of the multilayer light-emitting device is that, in step (6), a first solution is spin-coated onto the first electron transport layer and annealed at 100°C for 5 minutes to form a first thin film with a thickness of 20 nm, thereby obtaining the charge-generating layer. The quaternary ammonium salt polymer in the first solution is selected from the following structures:

[0183]

[0184] The quaternary ammonium salt polymer has a mass-average molecular weight Mw of 180,000, and the halogen is selected from bromine.

[0185] Comparative Example 2 of Multilayer Light Emitting Devices

[0186] The difference between this comparative example and Example 1 of the multilayer light-emitting device is that, in step (6), H3PMo is spin-coated onto the first electron transport layer. 12 O 40 A solution of ethylene glycol diethyl ether containing phosphomolybdic acid was prepared and annealed at 60°C for 5 min to form a second film with a thickness of 10 nm, thus obtaining the charge generation layer.

[0187] Test Result Analysis:

[0188] The driving voltage, current efficiency, and working life of the light-emitting devices prepared in Examples 1 to 7 of the multilayer light-emitting device, as well as Comparative Examples 1 and 2 of the multilayer light-emitting device, were tested. The test results are shown in Table 2.

[0189] The performance (driving voltage, current efficiency) of the stacked light-emitting device is tested using an IVL (Inductively Coupled Light) device at a current density of 10 mA / cm². 2 The voltage at which the device is tested is used as the driving voltage evaluation index, and the current efficiency when the brightness of the device is 1000 nits is used as the current efficiency evaluation index. The working life of the device is measured using a life aging device, and the time when the brightness of the light-emitting device decays to 95% under constant current conditions from an initial brightness of 1000 nits is used as the working life evaluation index.

[0190]

[0191]

[0192] Table 2

[0193] Table 2 shows that by comparing the experimental data of Examples 1-7 of the stacked light-emitting devices with Comparative Examples 1 and 2, it can be seen that Examples 1-7 all have lower driving voltages, significantly increased current efficiency, and significantly increased lifespan. Therefore, it can be concluded that using the composite film provided in this application as the charge generation layer generates dipole orientation capability in the stacked light-emitting device, thereby improving the electron injection efficiency of the charge generation layer. At the same time, since the second film is made of heteropolyacid material, it has a large electron affinity (LUMO absolute value greater than or equal to 4eV), which can be used as an electrode to inject holes into the second light-emitting unit, thereby improving the hole injection efficiency of the composite film, increasing current efficiency, reducing the operating current at the same brightness, and extending the lifespan of the stacked light-emitting device.

[0194] According to the experimental data of Comparative Example 1 of the stacked light-emitting device, its current efficiency is slightly improved and the driving voltage is slightly reduced. Therefore, only the quaternary ammonium salt polymer is used as the charge generation layer. Some cations and anions in the quaternary ammonium salt polymer are separated, thereby generating a certain dipole orientation capability. However, because some cations and anions are separated and move to the two light-emitting units, it causes some damage to the adjacent electron transport layer and hole injection layer, resulting in a reduced service life.

[0195] According to the experimental data of Comparative Example 2 of the stacked light-emitting device, it can be seen that its current efficiency is low, the driving voltage is high, and the lifetime is short. Therefore, the stacked light-emitting device prepared in Comparative Example 2 does not produce dipole orientation capability and does not improve the carrier transport efficiency of the charge generation layer.

[0196] In summary, the composite film provided in this application constructs an oriented dipole layer at the interface between the first and second films by combining the quaternary ammonium salt cations in the quaternary ammonium salt polymer of the first film with the heteropolyacid anions of the second film. This results in a large dipole orientation capability in the composite film, improving its electron injection efficiency. Simultaneously, since the second film is made of a heteropolyacid material, it has a large electron affinity (LUMO absolute value greater than or equal to 4 eV), which improves the hole injection efficiency of the composite film. Therefore, the composite film provided in this application improves the carrier injection efficiency of the multilayer light-emitting device and extends its lifespan.

[0197] Obviously, the embodiments described above are only some embodiments of this application, not all embodiments. The accompanying drawings show preferred embodiments of this application, but do not limit the patent scope of this application. This application can be implemented in many different forms; rather, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this application's specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the scope of patent protection of this application.

Claims

1. A composite film, characterized in that, It includes a first film and a second film stacked together; wherein the material of the first film includes a quaternary ammonium salt polymer, and the material of the second film includes a heteropoly acid.

2. The composite film according to claim 1, characterized in that, The monomers of the quaternary ammonium salt polymer have the structure shown in Formula I, and the quaternary ammonium salt polymer is formed by homopolymerization of the same monomer or copolymerization of different monomers: R1, R2 and R3 are each independently selected from C1 to C20 hydrocarbon groups and C1 to C20 hydroxyl groups that are unsubstituted or substituted by amino, halogen, hydroxyl, carboxyl, ester, acyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, hydrocarbon, or hydroxyl groups. L1 and L2 are each independently selected from unsubstituted or substituted amino, halogen, hydroxyl, carboxyl, ester, acyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, hydrocarbon, or hydroxyl groups of C1 to C20. Optionally, L1 or L2 can be connected to R2 or R3 respectively to form pyrrolidine quaternary ammonium salts or piperazine quaternary ammonium salts. X is selected from one or more of Cl, Br, and I.

3. The composite film according to claim 2, characterized in that, The cation in the quaternary ammonium salt polymer is selected from one or more of the following structural formulas a to d, wherein... In equations a and b, m is selected from integers no greater than 6; In formula c, R4 and R5 each appear independently selected from unsubstituted or substituted amino, halogen, hydroxyl, carboxyl, ester, acyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, hydrocarbon, or hydroxyl groups of C1 to C10 hydrocarbon groups and C1 to C10 hydroxyl groups. In formula d, R6 and R7 each appear independently selected from unsubstituted or substituted C1 to C10 hydrocarbon groups or C1 to C10 alkyl groups or alkyl groups of amino, halogen, hydroxyl, carboxyl, ester, acyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, hydrocarbon, or alkyloxy groups. The mass-average molecular weight (Mv) of the cation is ≥10000.

4. The composite film according to claim 3, characterized in that, The cations in the quaternary ammonium salt polymer are selected from one or more of the following structural formulas:

5. The composite film according to any one of claims 2 to 4, characterized in that, The mass-average molecular weight (Mw) of the quaternary ammonium salt polymer is ≥100,000.

6. The composite film according to claim 1, characterized in that, The heteropolyacid includes at least one compound having the following general formula: H n A x M y O z ; Wherein, A is selected from one or more of Cr, Fe, Ni, Al, P, Si, B, Ga, As, Sb, and Bi; M is selected from transition metals of group VB or group VIB, optionally, M is selected from one or more of Mo, W, V, Nb, and Ta, and A and M are different elements; x, y, and z satisfy: x is 1, y is 12, and z is 40; or x is 2, y is 18, and z is 62; or x is 1, y is 6, and z is 24; or x is 1, y is 9, and z is 32; or x is 1, y is 12, and z is 42; n is any positive number that satisfies the charge balance within the compound.

7. The composite film according to claim 6, characterized in that, The heteropolyacid is selected from H3PMo. 12 O 40 H6PMo 12 O 42 H6P2Mo 18 O 62 H3PW 12 O 40 H6P2W 18 O 62 H4PV 12 O 40 H3CrMo6O 24 H6SiMo 12 O 40 H3CrMo6O 24 H6NiMo9O 32 H3FeMo 12 O 40 One or more of them.

8. The composite film according to claim 1, characterized in that, The thickness of the first thin film is 1 nm to 50 nm, optionally, the thickness of the first thin film is 10 nm to 20 nm; and / or, The thickness of the second thin film is 1 nm to 50 nm, optionally, the thickness of the second thin film is 10 nm to 20 nm; and / or, The absolute value of the LUMO of the second thin film is greater than or equal to 4 eV.

9. A method for preparing a composite thin film, characterized in that, Includes the following steps: A first solution containing a quaternary ammonium salt polymer is provided, and the first solution is deposited to form a first thin film; A second solution containing a heteropoly acid is provided, and the second solution is deposited on the first film to form a second film, thereby obtaining the composite film.

10. The method for preparing the composite thin film according to claim 9, characterized in that, The first solution is prepared by the following steps: A third solution containing tertiary amine polymers and a fourth solution containing haloalkanes are provided; The first solution is obtained by mixing the third solution and the fourth solution according to a set mass ratio.

11. The method for preparing the composite thin film according to claim 10, characterized in that, The tertiary amine polymer is selected from one or more of the following structural formulas e to h; In formula g, R8 is selected from C1 to C10 hydrocarbon groups and C1 to C10 hydroxyl groups that are unsubstituted or substituted by amino, halogen, hydroxyl, carboxyl, ester, acyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, hydrocarbon, or hydroxyl groups. R9 in formula h is selected from C1 to C10 hydrocarbon groups and C1 to C10 alkyl groups that are unsubstituted or substituted by amino, halogen, hydroxyl, carboxyl, ester, acyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, hydrocarbon, or alkyloxy groups. The mass-average molecular weight (Mv) of the tertiary amine polymer is ≥10000.

12. The method for preparing the composite thin film according to claim 11, characterized in that, The tertiary amine polymer is selected from one or more of the following structural formulas:

13. The method for preparing the composite thin film according to claim 10, characterized in that, The haloalkane is selected from one or more of dibromo-n-pentane, dibromo-n-hexane, dibromo-n-heptane, and dibromo-n-octane; and / or, The set mass ratio is 10:1 to 1:

2.

14. A multilayer light-emitting device, characterized in that, It includes an anode and a cathode arranged opposite to each other, and at least two layers of light-emitting units stacked between the anode and the cathode; The stacked light-emitting device further includes a charge-generating layer disposed between two adjacent light-emitting units, wherein the charge-generating layer is a composite thin film as described in any one of claims 1 to 8 or is prepared by the method for preparing a composite thin film as described in any one of claims 9 to 13.

15. The stacked light-emitting device according to claim 14, characterized in that, The charge generation layer includes a first thin film and a second thin film stacked together, wherein the first thin film is located near the anode side and the second thin film is located near the cathode side. The surface potential difference between the first film and the second film is greater than or equal to 0.5V.

16. The stacked light-emitting device according to claim 14 or 15, characterized in that, The light-emitting unit includes a hole functional layer, a light-emitting layer and an electron functional layer stacked together, wherein the hole functional layer is located between the light-emitting layer and the anode, and the electron functional layer is located between the light-emitting layer and the cathode; The anode and / or cathode materials include one or more of metals, carbon materials, and metal oxides. The metals include one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg. The carbon materials include one or more of graphite, carbon nanotubes, graphene, and carbon fibers. The metal oxides include doped or undoped metal oxides, including one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, and AMO, or composite electrodes consisting of metal sandwiched between doped or undoped transparent metal oxides. These composite electrodes include one or more of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO2 / Ag / TiO2, and TiO2 / Al / TiO2; and / or... The light-emitting layer is a quantum dot light-emitting layer or an organic light-emitting layer; wherein, the material of the quantum dot light-emitting layer includes one or more of single-structure quantum dots and core-shell structure quantum dots, the material of the single-structure quantum dots, the core material of the core-shell structure quantum dots, and the shell material of the core-shell structure quantum dots are respectively selected from one or more of group II-VI compounds, group IV-VI compounds, group III-V compounds, and group I-III-VI compounds, and the shell of the core-shell structure quantum dots includes one or more layers; wherein, group II-VI compounds include, but are not limited to, CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, and Hg. One or more of Se, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe, and group IV-VI compounds include, but are not limited to, those... One or more of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe, and III-V compounds including but not limited to GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, and A One or more of the following compounds: lNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb; and group I-III-VI compounds, including but not limited to one or more of CuInS2, CuInSe2, and AgInS2.The organic light-emitting layer is made of one or more of the following materials: 4,4'-bis(N-carbazole)-1,1'-biphenyl:tris[2-(p-tolyl)pyridine-C2,N)iridium (II), 4,4',4”-tris(carbazole-9-yl)triphenylamine:tris[2-(p-tolyl)pyridine-C2,N)iridium, diaromatic anthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPX fluorescent materials, TBRb fluorescent materials and DBP fluorescent materials, polyacetylene and its derivatives, poly(p-phenylene) and its derivatives, polythiophene and its derivatives, and polyfluorene and its derivatives; and / or, The electronic functional layer includes an electron transport layer and / or an electron injection layer, wherein the electron transport layer and / or electron injection layer comprises inorganic or organic materials; wherein the inorganic material is selected from one or more of the following: doped or undoped zinc oxide, barium oxide, aluminum oxide, nickel oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, zinc aluminum oxide, zinc manganese oxide, zinc tin oxide, zinc lithium oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc tin sulfide, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, and barium titanate; and the doped elements include aluminum, magnesium, lithium, manganese, yttrium, and lanthanum. One or more of copper, nickel, zirconium, cerium, and gadolinium; the organic material is selected from one or more of quinoxaline compounds, imidazole compounds, triazine compounds, fluorene compounds, hydroxyquinoline compounds, phosphooxide compounds, pyridine compounds, quinoline compounds, isoquinoline compounds, benzimidazole compounds, pyrazine compounds, acridine compounds, pyrazole compounds, pyrimidine compounds, pyridazine compounds, imidazole compounds, phenanthroline compounds, isoindole compounds, oxazole compounds, isoxazole compounds, phosphorus oxide compounds, triarylborane compounds, and tetraarylsilane compounds.

17. The stacked light-emitting device according to claim 14, characterized in that, The stacked light-emitting device includes an anode, a first hole injection layer, a first hole transport layer, a first light-emitting layer, a first electron transport layer, a charge generation layer, a second hole injection layer, a second hole transport layer, a second light-emitting layer, a second electron transport layer, and a cathode, which are stacked sequentially.

18. A display device, characterized in that, The display device includes the stacked light-emitting device according to any one of claims 14 to 17.

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