Composite material, carrier functional film and application thereof

Abstract

The invention belongs to the technical field of display, and relates to a composite material, a carrier functional film and application thereof. The composite material comprises a carrier transport material and an additive. The thin film is prepared from the composite material, so that the thin film has the characteristics of large size, continuous and layered crystal growth, and the surface flatness reaches a molecular level, so that carriers can be transported in the thin film.

Description

Technical Field

[0001] The present application relates to the field of display technologies, and more particularly, to a composite material, a carrier functional thin film, and their applications. Background Art

[0002] In recent years, a new type of OLED device, namely crystalline organic light-emitting diode (C-OLED), has emerged. A C-OLED is an OLED device that uses a crystalline organic semiconductor material as a light-emitting layer. Its characteristics are high crystallinity and high fluorescence quantum efficiency, which can improve the electroluminescence efficiency and brightness of the C-OLED. Moreover, because the crystalline organic semiconductor material has good thermal stability and antioxidant properties, it can improve the stability and lifespan of the C-OLED. However, the performance of the electron transport material in existing C-OLEDs is poor, and the carrier transport performance of the device needs to be further improved. Summary of the Invention

[0003] Based on this, the present application provides a composite material, a carrier functional thin film, and their applications.

[0004] To solve the above technical problems, the embodiments of the present application provide a composite material, adopting the following technical solutions:

[0005] A composite material, comprising: a carrier transport material, an additive, and the additive is selected from at least one of Formula I, II, III, IV, and V:

[0006]

[0007]

[0008] Wherein, each of R1 to R6 is independently selected from one of O(CH2) n CH3, and COOCH3, and n is an integer selected from 1 to 7; R7 to R 25 is selected from one of Formula i, ii, iii, iv, v, vi, and vii:

[0009]

[0010]

[0011] Wherein, R 26 to R 52Each independently selected from hydrogen, deuterium, amino group, halogen, hydroxyl group, carboxyl group, nitro group, sulfonic acid group, aldehyde group, mercapto group, cyano group; a C1-C20 hydrocarbon group, a C1-C20 hydrocarbon oxy group, a cycloalkyl group with 3 to 60 ring atoms, a heterocycloalkyl group with 3 to 60 ring atoms, an aryl group with 5 to 60 ring atoms, a heteroaryl group with 5 to 60 ring atoms, an aryloxy group with 5 to 60 ring atoms, a heteroaryloxy group with 5 to 60 ring atoms, which is unsubstituted or substituted by amino group, halogen, hydroxyl group, carboxyl group, nitro group, sulfonic acid group, aldehyde group, mercapto group, cyano group, and one or more combinations thereof, wherein the heteroatoms in the heteroaryl group or heteroaryloxy group are N, S, O, P, Si, and the number of heteroatoms is 1-20.

[0012] To solve the above technical problems, the embodiments of the present application further provide a method for preparing a thin film, adopting the following technical solutions:

[0013] A method for preparing a thin film, comprising:

[0014] Providing a solvent and the composite material as described above;

[0015] Mixing the solvent and the composite material to obtain a mixed solution;

[0016] Depositing the mixed solution to obtain the thin film.

[0017] To solve the above technical problems, the embodiments of the present application further provide a thin film, adopting the following technical solutions:

[0018] A thin film, which is prepared by the thin film preparation method as described above, or comprises the composite material as described in any one of the above.

[0019] To solve the above technical problems, the embodiments of the present application further provide an optoelectronic device, adopting the following technical solutions:

[0020] An optoelectronic device, comprising a first electrode, a carrier functional thin film, a light-emitting layer, and a second electrode which are stacked;

[0021] The material of the carrier functional thin film comprises the composite material as described above, or the carrier functional thin film is the thin film as described above.

[0022] To solve the above technical problems, the embodiments of the present application further provide a display device, adopting the following technical solutions:

[0023] A display device, comprising the optoelectronic device as described above.

[0024] Compared with the prior art, the present application has the following beneficial effects: The composite material provided in this embodiment can be used to prepare a thin film. By adding an additive to the charge carrier transport material, it is beneficial for the charge carriers to transport within the thin film, thereby improving the charge carrier transport performance of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the solution of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0026] Figure 1 is a flowchart of an embodiment of a method for preparing a charge carrier functional thin film provided by the present application;

[0027] Figure 2 is a schematic diagram of an embodiment of an optoelectronic device provided by the present application;

[0028] Figure 3 is a voltage-current density curve graph of Embodiments 1 to 12 and Comparative Examples 1 to 4;

[0029] Figure 4 is a current density-external quantum efficiency curve graph of Embodiments 13 to 24 and Comparative Examples 5 to 8.

[0030] Reference numerals: 1, first electrode; 2, charge carrier functional thin film; 3, light-emitting layer; 4, second electrode. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used in the description of the present application in the specification are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the specification and claims of the present application or the above drawings are used to distinguish different objects and are not used to describe a specific order.

[0032] Reference to "embodiment" herein means that a specific feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0033] In order to enable those skilled in the art to better understand the solution of this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings.

[0034] The embodiments of this application provide a composite material, including: a charge carrier transport material, an additive, and the additive is selected from at least one of Formula I, II, III, IV, and V:

[0035]

[0036]

[0037] Wherein, R1 to R6 are each independently selected from one of O(CH2) n CH3, COOCH3, and n is an integer selected from 1 to 7; R7 to R 25 is selected from one of Formula i, ii, iii, iv, v, vi, and vii:

[0038]

[0039] Wherein, R 26 to R 52 are each independently selected from hydrogen, deuterium, amino group, halogen, hydroxyl group, carboxyl group, nitro group, sulfonic acid group, aldehyde group, mercapto group, cyano group; C1-C20 linear hydrocarbon group, C1-C20 linear hydrocarbon oxy group, cycloalkyl group with 3 to 60 ring atoms, heterocyclic hydrocarbon group with 3 to 60 ring atoms, aryl group with 5 to 60 ring atoms, heteroaryl group with 5 to 60 ring atoms, aryloxy group with 5 to 60 ring atoms, heteroaryloxy group with 5 to 60 ring atoms that are unsubstituted or substituted by amino group, halogen, hydroxyl group, carboxyl group, nitro group, sulfonic acid group, aldehyde group, mercapto group, cyano group, and one or more combinations thereof, wherein the heteroatoms in the heteroaryl group or heteroaryloxy group are N, S, O, P, Si, and the number of heteroatoms is 1-20.

[0040] The composite material provided by this embodiment can be used to prepare a thin film. By adding an additive to the charge carrier transport material, the thin film has the characteristics of large size, continuous, and layered crystal growth. Specifically, the molecules in the additive form a vertically oriented columnar structure through π-π interactions to epitaxially grow a large-size and continuous thin film on the substrate, and the surface flatness reaches the molecular level to facilitate the transport of charge carriers in the thin film.

[0041] Furthermore, in this embodiment, a composite material is used to prepare a thin film, enabling the thin film to have the characteristics of large size, continuous, and layered crystal growth, which is conducive to the preparation of an ordered light-emitting layer; since a highly oriented light-emitting layer is formed on the thin film, the light-emitting layer and the thin film have an epitaxial relationship in structure, thereby preparing a crystalline light-emitting layer. In this embodiment, a thin film prepared from a composite material is used to prepare a crystalline light-emitting layer, achieving simple, efficient, and low-cost C-OLED preparation; and in this embodiment, the crystallization-induced fluorescence enhancement effect of the thin film prepared from the composite material is utilized to realize a C-OLED device with high efficiency, high brightness, and high stability.

[0042] Furthermore, the additive is selected from benzo[c]phenanthrene-based discotic liquid crystal molecules.

[0043] In this embodiment, benzo[c]phenanthrene-based discotic liquid crystal molecules have the following advantages: relatively easy to synthesize, easy to modify the structure, and easy to synthesize and purify; having good solubility to facilitate processing into optoelectronic thin film devices through solution or inkjet printing technology; rich liquid crystal phase types to form a unique columnar phase structure with one-dimensional order and quasi-one-dimensional conjugated electron cloud distribution; thermally and chemically stable, having high thermal stability and a wide phase temperature range; high charge transport rate along the column axis, endowing it with good semiconductor and optical properties.

[0044] Compared with other types of liquid crystal molecules, benzo[c]phenanthrene-based discotic liquid crystal molecules also have the following advantages: having strong π-π interactions, enabling them to form a closely packed columnar structure in the direction perpendicular to the substrate, which is conducive to the transport of carriers in the thin film; having a large molecular plane area, enabling them to form a large contact area in the direction parallel to the disk surface, which is conducive to improving the surface flatness and orientation of the thin film; having high molecular symmetry, enabling them to form good order and orientation in the columnar phase, which is conducive to improving the photoelectric conversion efficiency of the thin film.

[0045] Furthermore, when the additive is selected from Formula I, the structure of the additive is one of Formulas VIII, IX, and X:

[0046]

[0047] Specifically, Formula VIII is 2,3,6,7,10,11-hexakis(hexyloxy)benzo[c]phenanthrene, and the CAS number is: 70351-86-9.

[0048] Specifically, Formula IX is 2,3,6,7,10,11-hexakis(n-octyloxy)benzo[c]phenanthrene, and the CAS number is: 70351-87-0.

[0049] Specifically, Formula X is 3,6,10,11-tetrakis(pentyloxy)triphenylene-2,7-diyl bis(2,2-dimethylpropionate) (T5DP-2,7).

[0050] Specifically, Formula II is perylene bisimide (PBI).

[0051] Specifically, Formula III is 1,3,5-trimethoxybenzene (THB).

[0052] Specifically, Formula IV is hexahydroxy triphenyl (HHT).

[0053] Specifically, Formula V is hexahydroxy-CTTV (HHCTTV).

[0054] Further, the carrier transport material is selected from at least one of PVK (poly(N-vinylcarbazole)), CDBP (4,4'-bis(9H-carbazol-9-yl)-2,2'-dimethylbiphenyl), mCBP (3,3-bis(carbazolyl)biphenyl; 3,3'-bis(9-carbazolyl)biphenyl), CBP ((4,4'-bis(9-carbazolyl)biphenyl)), mCP (methylcyclopentenolone), TCTA (4,4',4''-tris(carbazol-9-yl)triphenylamine), NPB (N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine).

[0055] Further, the mass ratio of the carrier transport material to the additive is (60 - 90):(40 - 10).

[0056] In this embodiment, the mass ratio of the carrier transport material to the additive is (60 - 90):(40 - 10), so that the film prepared from the composite material can not only meet the carrier transport efficiency, but also meet the epitaxial growth of large-size and continuous films of the molecules in the crystal additive on the substrate.

[0057] In some alternative embodiments of this embodiment, the mass ratio of the carrier transport material to the additive is within the range of any one or any two of 60:40, 65:35, 70:30, 75:25, 80:20, 85:15, 90:10, etc.

[0058] The embodiment of the present application also provides a method for preparing a film, as Figure 1 shown, the method includes the following steps:

[0059] S10. Provide a solvent and the composite material as described above;

[0060] S20. Mix the solvent and the composite material to obtain a mixed solution;

[0061] S30. Deposit the mixed solution to obtain the film.

[0062] In this embodiment, a mixed solution comprising a composite material and a solvent is used to prepare a thin film, wherein a carrier transport material and an additive endow the prepared thin film with the characteristics of large-size, continuous, and layered crystal growth. Specifically, the molecules in the additive form a vertically oriented columnar structure through π-π interactions to epitaxially grow a large-size and continuous thin film on the substrate, and the surface flatness reaches the molecular level, which is conducive to the transport of carriers within the thin film.

[0063] Furthermore, in this embodiment, a composite material is used to prepare the thin film, enabling the thin film to have the characteristics of large-size, continuous, and layered crystal growth, which is conducive to the preparation of an ordered light-emitting layer; since a highly oriented light-emitting layer is formed on the thin film, the structure of the light-emitting layer and the thin film has an epitaxial relationship in orientation, thereby preparing a crystalline light-emitting layer. This embodiment utilizes the crystallization-induced fluorescence enhancement effect of the thin film prepared from the composite material to achieve a C-OLED device with high efficiency, high brightness, and high stability.

[0064] Furthermore, in this embodiment, a mixed solution and a spin coating method are used to prepare the thin film, which simplifies the process flow of C-OLED, reduces the preparation cost, and enables the preparation of C-OLED on a large area or a flexible substrate.

[0065] Furthermore, the step S30 of depositing the mixed solution to obtain the thin film specifically includes:

[0066] Annealing the mixed solution, wherein the annealing temperature is 200 - 260 °C.

[0067] In this embodiment, annealing the mixed solution weakens the interaction between the molecules in the additive and other film layers or the substrate, making it less than the interaction between molecules, so that the molecules stand up and grow aggregately.

[0068] Specifically, the molecules in the additive are discotic liquid crystal molecules. The interaction between the discotic liquid crystal molecules and other film layers or the substrate is mainly caused by the van der Waals force and electrostatic force between molecules. The magnitude of these forces is related to the distance and orientation between molecules. Generally speaking, the closer the distance, the more parallel the orientation, and the stronger the interaction; increasing the annealing temperature can increase the thermal motion of molecules, making the distance between molecules increase and the orientation more random, thereby reducing the interaction between molecules; therefore, the interaction between the discotic liquid crystal molecules and other film layers or the substrate will be weakened, while the interaction between the discotic liquid crystal molecules will be relatively enhanced. When the interaction between the discotic liquid crystal molecules and other film layers or the substrate is less than the interaction between the discotic liquid crystal molecules, the discotic liquid crystal molecules tend to be induced to form large-size, continuous, and layered crystal growth on the substrate.

[0069] Furthermore, the annealing temperature is 200 - 260 °C.

[0070] In this embodiment, the annealing temperature is 200 - 260 °C, which can increase the thermal motion of molecules, increase the distance between molecules, make the orientation more random, and thus reduce the interaction between molecules.

[0071] In some alternative embodiments of this embodiment, the annealing temperature is any one or the range between any two of 200 °C, 205 °C, 210 °C, 215 °C, 220 °C, 225 °C, 230 °C, 235 °C, 240 °C, 245 °C, 250 °C, 255 °C, 260 °C, etc.

[0072] Furthermore, the solvent is selected from methyl benzoate, toluene, xylene, chlorobenzene, chloroform, tetrahydrofuran, acetonitrile, dichloromethane.

[0073] In this embodiment, the above-mentioned solvent is an organic solvent with good solubility and can dissolve the composite material.

[0074] Furthermore, the concentration of the composite material in the mixed solution is 5 - 15 mg / ml.

[0075] In this embodiment, according to the different viscosities of the solvent, the required concentration of the mixed solution is also different, and this application does not limit it here.

[0076] In some alternative embodiments of this embodiment, the concentration of the composite material in the mixed solution is any one or the range between any two of 5 mg / ml, 6 mg / ml, 7 mg / ml, 8 mg / ml, 9 mg / ml, 10 mg / ml, 11 mg / ml, 12 mg / ml, 13 mg / ml, 14 mg / ml, 15 mg / ml, etc.

[0077] The embodiment of the present application also provides a thin film, which is prepared by the thin film preparation method described above or includes the composite material described above.

[0078] In this embodiment, a thin film is prepared by using a mixed solution including a composite material and a solvent, where the carrier transport material and the additive make the prepared thin film have the characteristics of large size, continuous, and layered crystal growth. Specifically, the molecules in the additive form a vertically oriented columnar structure through π-π interaction to epitaxially grow a large-size and continuous thin film on the substrate, and the surface flatness reaches the molecular level to facilitate the transport of carriers in the thin film.

[0079] Furthermore, in this embodiment, a composite material is used to prepare a thin film, enabling the thin film to have the characteristics of large size, continuous, and layered crystal growth, which is conducive to the preparation of an ordered light-emitting layer. Since a highly oriented light-emitting layer is formed on the thin film, the structure of the light-emitting layer and the thin film has an epitaxial relationship in orientation, thereby preparing a crystalline light-emitting layer. In this embodiment, a thin film prepared from a composite material is used to prepare a crystalline light-emitting layer, achieving simple, efficient, and low-cost C-OLED preparation. Moreover, the crystallization-induced fluorescence enhancement effect of the thin film prepared from the composite material in this embodiment is utilized to realize a C-OLED device with high efficiency, high brightness, and high stability.

[0080] The above solution will be further described below in conjunction with specific implementation examples. The preferred embodiments of the present invention are described in detail as follows:

[0081] Example 1:

[0082] (1) Use a transparent conductive thin film ITO as the anode, with a thickness of 50 nm;

[0083] (2) Deposit PEDOT:PSS as the hole injection layer on the ITO by solution method, with a thickness of 30 nm

[0084] (3) Deposit a solvent and a composite material as a thin film on the hole injection layer by solution method, with a thickness of 25 nm. Among them, the charge transport material in the composite material is selected from TCTA, and the additive is selected from T5DP-2,7; the mass ratio of TCTA to T5DP-2,7 is 90:10;

[0085] (4) Deposit an OLED light-emitting layer material on the hole transport layer by solution method, where PAC is used as the light-emitting material, with a thickness of 35 nm;

[0086] (5) Deposit MoO3 as the hole injection layer on the light-emitting layer by evaporation method, with a thickness of 1 nm;

[0087] (6) Deposit Al as the cathode on the hole injection layer by evaporation method, with a thickness of 100 nm.

[0088] Example 2:

[0089] The difference from Example 1 is that the mass ratio of TCTA to T5DP-2,7 is 80:20.

[0090] Example 3:

[0091] The difference from Example 1 is that the mass ratio of TCTA to T5DP-2,7 is 70:30.

[0092] Example 4:

[0093] It is different from Example 1 in that the mass ratio of TCTA to T5DP-2,7 is 60:40.

[0094] Example 5:

[0095] It is different from Example 1 in that the additive is selected from 2,3,6,7,10,11-hexakis(hexyloxy)triphenylene.

[0096] Example 6:

[0097] It is different from Example 5 in that the mass ratio of TCTA to 2,3,6,7,10,11-hexakis(hexyloxy)triphenylene is 80:20.

[0098] Example 7:

[0099] It is different from Example 5 in that the mass ratio of TCTA to 2,3,6,7,10,11-hexakis(hexyloxy)triphenylene is 70:30.

[0100] Example 8:

[0101] It is different from Example 5 in that the mass ratio of TCTA to 2,3,6,7,10,11-hexakis(hexyloxy)triphenylene is 60:40.

[0102] Example 9:

[0103] It is different from Example 1 in that the additive is selected from 2,3,6,7,10,11-hexakis(n-octyloxy)triphenylene.

[0104] Example 10:

[0105] It is different from Example 9 in that the mass ratio of TCTA to 2,3,6,7,10,11-hexakis(n-octyloxy)triphenylene is 80:20.

[0106] Example 11:

[0107] It is different from Example 9 in that the mass ratio of TCTA to 2,3,6,7,10,11-hexakis(n-octyloxy)triphenylene is 70:30.

[0108] Example 12:

[0109] It is different from Example 9 in that the mass ratio of TCTA to 2,3,6,7,10,11-hexakis(n-octyloxy)triphenylene is 60:40.

[0110] Comparative Example 1:

[0111] (1) Use indium tin oxide (ITO) transparent conductive film as the anode, with a thickness of 50 nm;

[0112] (2) Deposit PEDOT:PSS as the hole injection layer on the ITO by solution method, with a thickness of 30 nm

[0113] (3) Deposit TCTA as a thin film on the hole injection layer by solution method, with a thickness of 25 nm.

[0114] (4) Deposit the OLED light-emitting layer material on the hole transport layer by solution method, using PAC as the light-emitting material, with a thickness of 35 nm;

[0115] (5) Deposit MoO3 as the hole injection layer on the light-emitting layer by evaporation method, with a thickness of 1 nm;

[0116] (6) Deposit Al as the cathode on the hole injection layer by evaporation method, with a thickness of 100 nm.

[0117] Comparative Example 2:

[0118] The difference from Comparative Example 1 is that in step (3), T5DP-2,7 is deposited as a thin film on the hole injection layer by solution method.

[0119] Comparative Example 3:

[0120] The difference from Comparative Example 1 is that in step (3), 2,3,6,7,10,11-hexa(hexyloxy)triphenylene is deposited as a thin film on the hole injection layer by solution method.

[0121] Comparative Example 4:

[0122] The difference from Comparative Example 1 is that in step (3), 2,3,6,7,10,11-hexa(n-octyloxy)triphenylene is deposited as a thin film on the hole injection layer by solution method.

[0123] Experimental test analysis: The devices prepared in Examples 1 to 12 and Comparative Examples 1 to 4 were subjected to experimental test analysis, and the analysis results are shown in Table 1.

[0124] Table 1

[0125] <![CDATA[Carrier transport efficiency / cm 2 V –1 s –1 > Example 1 <![CDATA[2.5×10 –3 > Example 2 <![CDATA[3×10 –3 > Example 3 <![CDATA[2.7×10 –3 > Example 4 <![CDATA[2.6×10 –3 > Example 5 <![CDATA[2.7×10 –3 > Example 6 <![CDATA[2.8×10 –3 > Example 7 <![CDATA[2.5×10 –3 > Example 8 <![CDATA[2.5×10 –3 > Example 9 <![CDATA[2.9×10 –3 > Example 10 <![CDATA[2.6×10 –3 > Example 11 <![CDATA[2.7×10 –3 > Example 12 <![CDATA[2.5×10 –3 > Comparative Example 1 <![CDATA[7.3×10 –5 > Comparative Example 2 <![CDATA[8.7×10 –4 > Comparative Example 3 <![CDATA[4.6×10 –4 > Comparative Example 4 <![CDATA[5.9×10 –4 >

[0126] From Table 1 and Figure 3It can be seen that the carrier transport efficiencies of Examples 1 to 12 are all better than those of Comparative Examples 1 to 4. Among them, in the composite materials of Examples 1 to 4, the carrier transport material is selected from TCTA, and the additive is selected from T5DP-2,7; in the composite materials of Examples 5 to 8, the carrier transport material is selected from TCTA, and the additive is selected from 2,3,6,7,10,11-hexa(hexyloxy)triphenylene; in the composite materials of Examples 9 to 12, the carrier transport material is selected from TCTA, and the additive is selected from 2,3,6,7,10,11-hexa(n-octyloxy)triphenylene; while in Comparative Example 1, only the carrier transport material TCTA is used to prepare the thin film, in Comparative Example 2, only the additive T5DP-2,7 is used to prepare the thin film, in Comparative Example 3, only the additive 2,3,6,7,10,11-hexa(hexyloxy)triphenylene is used to prepare the thin film, and in Comparative Example 4, only the additive 2,3,6,7,10,11-hexa(n-octyloxy)triphenylene is used to prepare the thin film. It shows that using the composite material including the carrier transport material and the additive to prepare the thin film can effectively improve the carrier transport efficiency of the thin film.

[0127] An embodiment of the present application further provides an optoelectronic device, such as Figure 2 shown, the optoelectronic device includes a first electrode 1, a carrier functional thin film 2, a light-emitting layer 3, and a second electrode 4 which are stacked; the material of the carrier functional thin film includes the composite material as described above, or the carrier functional thin film is the thin film as described above.

[0128] In this embodiment, a mixed solution including the composite material and a solvent is used to prepare the carrier functional thin film 2. Among them, the carrier transport material and the additive make the prepared carrier functional thin film 2 have the characteristics of large-size, continuous, and layered crystal growth. Specifically, the molecules in the additive form a vertically oriented columnar structure through π-π interaction to epitaxially grow a large-size and continuous thin film on the substrate, and the surface flatness reaches the molecular level to facilitate the transport of carriers in the carrier functional thin film 2.

[0129] In this embodiment, the composite material is used to prepare the carrier functional thin film 2, so that the carrier functional thin film 2 has the characteristics of large-size, continuous, and layered crystal growth, which is beneficial to the preparation of the ordered light-emitting layer 3; since the highly oriented light-emitting layer 3 is formed on the carrier functional thin film, the structure of the light-emitting layer 3 and the carrier functional thin film 2 has an orientation epitaxial relationship, thereby preparing a crystalline light-emitting layer 3. In this embodiment, the carrier functional thin film 2 is prepared by using the composite material to prepare the crystalline light-emitting layer 3, realizing simple, efficient, and low-cost C-OLED preparation; and in this embodiment, the crystallization-induced fluorescence enhancement effect of the carrier functional thin film 2 prepared by using the composite material is utilized to realize a C-OLED device with high efficiency, high brightness, and high stability.

[0130] In this embodiment, the carrier functional thin film 2 is used as a hole transport layer.

[0131] Furthermore, the material of the light-emitting layer 3 includes at least one of PABBP, PATPA, mPAC, PAC, 4,4'-bis(N-carbazolyl)-1,1'-biphenyl: tris[2-(p-tolyl)pyridine-C2,N]iridium(III), 4,4',4''-tris(carbazol-9-yl)triphenylamine: tris[2-(p-tolyl)pyridine-C2,N]iridium, diarylanthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent material, TTPX fluorescent material, TBRb fluorescent material, and DBP fluorescent material, polyacetylene and its derivatives, poly(p-phenylene) and its derivatives, polythiophene and its derivatives, polyfluorene and its derivatives.

[0132] Preferably, the material of the light-emitting layer 3 includes PABBP, PATPA, mPAC, PAC.

[0133] In this embodiment, PABBP, PATPA, mPAC, and PAC belong to anthracene-based hot exciton materials, and anthracene-based hot exciton materials have the following advantages: 1) High-energy conversion does not require the separation design of frontier orbitals to obtain a small T1-S1 energy difference. Therefore, the S1 state can be a LE excited state with high luminescence efficiency to simultaneously achieve high exciton utilization rate and high fluorescence efficiency; 2) Since intersystem crossing occurs in a high-energy excited state, the reverse intersystem crossing process is very fast, and the number of excitons converted to the T1 state decreases, so that the accumulation of long-lived T1 excitons leading to triplet-triplet annihilation can be effectively avoided, making the devices prepared from hot excitons often have good device stability; 3) The donor-acceptor strength of the hot exciton material is moderate, and the intramolecular CT state effect is relatively weak. Blue-light hot exciton materials usually have good color purity, which makes them have potential advantages in the design of pure blue and deep blue light materials and provides new ideas for the research of organic electrically pumped lasers and other miniaturized optoelectronic integrated devices.

[0134] Further, the first electrode 1 and the second electrode 4 are each selected from one or more of a metal electrode, a silicon-carbon electrode, a doped or undoped metal oxide electrode, and a composite electrode; wherein, the material of the metal electrode is selected from at least one of Al, Ag, Cu, Mo, Au, Ba, Ca, and Mg; the material of the silicon-carbon electrode is selected from at least one of silicon, graphite, carbon nanotubes, graphene, and carbon fiber; the material of the doped or undoped metal oxide electrode is selected from at least one of ITO, FTO, ATO, AZO, GZO, IZO, MZO, and AMO; the material of the composite electrode is selected from at least one of 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, TiO2 / Ag / TiO2, and TiO2 / Al / TiO2.

[0135] Further, a hole injection layer (not shown) is provided between the first electrode 1 and the carrier functional thin film 2, and the material of the hole injection layer includes at least one of TFB, CuPc, PVK, Poly-TPD, PFB, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, T·APC, MCC, F4-TCNQ, HATCN, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, polyaniline, transition metal oxides, transition metal sulfides, transition metal stannides, doped graphene, undoped graphene, and C60.

[0136] Further, an electron functional layer (not shown) is provided between the second electrode 4 and the light-emitting layer 3. The electron functional layer includes an electron transport layer and / or an electron injection layer. When the electron functional layer includes an electron injection layer and an electron transport layer, the electron injection layer is disposed adjacent to the second electrode, and the electron transport layer is disposed adjacent to the light-emitting layer. The material of the electron transport layer is selected from at least one of doped or undoped metal oxides and organic electron transport materials. The doped or undoped metal oxides are selected from at least one of doped or undoped zinc oxide, tin oxide, titanium oxide, and zirconium oxide, and the doping elements include at least one of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, and gadolinium. The organic electron transport materials are selected from [6,6]-phenyl C71 butyric acid methyl ester, [6,6]-phenyl C61 butyric acid methyl ester, organic fullerene materials, 2-ethyl-1-(4-(10-(2-naphthyl)-9-anthryl)phenyl)-1H-benzimidazole, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, 3,3'-[5'-[3-(3-pyridyl)phenyl], 4,6-bis(3,5-bis(3-pyridyl)phenyl)-2-methylpyrimidine, phenyldipyridyl beryllium, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene(, 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole, 1,3,5-tris[(3-pyridyl)-3-phenyl]benzene, tris(8-hydroxyquinoline) aluminum, 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline, 4,7-diphenyl-1,10-phenanthroline, poly[(9,9-bis(3'-((N,N-dimethyl)-N-ethylammonium)-propyl)-2,7-fluorene)-2,7-(9,9-dioctylfluorene)] dibromide, poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-2,7-(9,9-dioctylfluorene)], 2,7-bis(diphenylphosphino)-9,9'-spirobi[fluorene], Alq3, TSPO1, TmPyPB, PBD, Beq2, TAZ, SPPO13; The material of the electron injection layer is selected from at least one of Yb, yttrium fluoride, Li, LiF, NaF, CeF, CsCO3, Cs, KBH4, or KH.

[0137] The above solution will be further described below in conjunction with specific implementation examples. The preferred embodiments of the present invention are described in detail as follows:

[0138] Example 13:

[0139] The charge transport material in the composite material is selected from TCTA, and the additive is selected from T5DP-2,7; the mass ratio of TCTA to T5DP-2,7 is 90:10.

[0140] (1) Use indium tin oxide (ITO) transparent conductive film as the anode, with a thickness of 50 nm;

[0141] (2) Deposit PEDOT:PSS on the ITO by solution method as the hole injection layer, with a thickness of 30 nm;

[0142] (3) Deposit a composite material on the hole injection layer by solution method as the carrier functional film, with a thickness of 25 nm;

[0143] (4) Deposit a light-emitting layer material on the carrier functional film by solution method, using PAC as the light-emitting material, with a thickness of 35 nm;

[0144] (5) Deposit TmPyPB on the light-emitting layer by evaporation method as the electron transport layer, with a thickness of 30 nm;

[0145] (6) Deposit Li on the electron transport layer by evaporation method as the electron injection layer, with a thickness of 1 nm;

[0146] (7) Deposit Al on the electron injection layer by evaporation method as the cathode, with a thickness of 100 nm.

[0147] Example 14:

[0148] The difference from Example 1 is that the mass ratio of TCTA to T5DP-2,7 is 80:20.

[0149] Example 15:

[0150] The difference from Example 1 is that the mass ratio of TCTA to T5DP-2,7 is 70:30.

[0151] Example 16:

[0152] The difference from Example 1 is that the mass ratio of TCTA to T5DP-2,7 is 60:40.

[0153] Example 17:

[0154] The difference from Example 5 is that the additive is selected from 2,3,6,7,10,11-hexa(hexyloxy)triphenylene.

[0155] Example 18:

[0156] The difference from Example 5 is that the mass ratio of TCTA to 2,3,6,7,10,11-hexa(hexyloxy)triphenylene is 80:20.

[0157] Example 19:

[0158] The difference from Example 5 is that the mass ratio of TCTA to 2,3,6,7,10,11 - hexakis(hexyloxy)terrylene is 70:30.

[0159] Example 20:

[0160] The difference from Example 5 is that the mass ratio of TCTA to 2,3,6,7,10,11 - hexakis(hexyloxy)terrylene is 60:40.

[0161] Example 21:

[0162] The difference from Example 1 is that the additive is selected from 2,3,6,7,10,11 - hexakis(n - octyloxy)terrylene.

[0163] Example 22:

[0164] The difference from Example 9 is that the mass ratio of TCTA to 2,3,6,7,10,11 - hexakis(n - octyloxy)terrylene is 80:20.

[0165] Example 23:

[0166] The difference from Example 9 is that the mass ratio of TCTA to 2,3,6,7,10,11 - hexakis(n - octyloxy)terrylene is 70:30.

[0167] Example 24:

[0168] The difference from Example 9 is that the mass ratio of TCTA to 2,3,6,7,10,11 - hexakis(n - octyloxy)terrylene is 60:40.

[0169] Comparative Example 5:

[0170] (1) Using the transparent conductive film ITO as the anode, with a thickness of 50 nm;

[0171] (2) Depositing PEDOT:PSS as the hole injection layer on the ITO by solution method, with a thickness of 30 nm;

[0172] (3) Depositing the carrier transport material TCTA as the hole transport layer of carriers on the hole injection layer by solution method, with a thickness of 25 nm;

[0173] (4) Depositing the OLED light - emitting layer material on the carrier functional film by solution method, using PAC as the light - emitting material, with a thickness of 35 nm;

[0174] (5) Deposit TmPyPB as the electron transport layer on the light-emitting layer by vapor deposition, with a thickness of 30 nm;

[0175] (6) Deposit Li as the electron injection layer on the electron transport layer by vapor deposition, with a thickness of 1 nm;

[0176] (7) Deposit Al as the cathode on the electron injection layer by vapor deposition, with a thickness of 100 nm.

[0177] Comparative Example 6:

[0178] The difference from Comparative Example 1 is that in step (3), the additive T5DP-2,7 is deposited as the carrier functional thin film on the hole injection layer by solution method, with a target thickness of 25 nm.

[0179] Comparative Example 7:

[0180] The difference from Comparative Example 1 is that in step (3), the additive 2,3,6,7,10,11-hexa(hexyloxy)triphenylene is deposited as the carrier functional thin film on the hole injection layer by solution method, with a target thickness of 25 nm.

[0181] Comparative Example 8:

[0182] The difference from Comparative Example 1 is that in step (3), the additive 2,3,6,7,10,11-hexa(n-octyloxy)triphenylene is deposited as the carrier functional thin film on the hole injection layer by solution method, with a target thickness of 25 nm.

[0183] Experimental test analysis: The devices prepared in Examples 13 to 24 and Comparative Examples 5 to 8 were subjected to experimental test analysis, and the analysis results are shown in Table 2.

[0184] Table 2

[0185]

[0186]

[0187] Among them, V@10 mA / cm2 represents the driving voltage corresponding to a current density of 10 mA / cm2; EQE@10 mA / cm2 represents the EQE corresponding to a current density of 10 mA / cm2; T95(h)@1000 cd / m2 represents the time elapsed when the device is continuously lit at an initial brightness of 1000 cd / m2 until the brightness decays to 95% of the initial brightness (here it is 950 cd / m2).

[0188] From Table 2 and Figure 4It can be seen that the driving voltages, EQEs, and luminance decay times of Examples 13 to 24 are superior to those of Comparative Examples 4 to 8. Among them, in the composite materials of Examples 113 to 16, the charge carrier transport material is selected from TCTA, and the additive is selected from T5DP-2,7; in the composite materials of Examples 17 to 20, the charge carrier transport material is selected from TCTA, and the additive is selected from 2,3,6,7,10,11-hexakis(hexyloxy)triphenylene; in the composite materials of Examples 21 to 24, the charge carrier transport material is selected from TCTA, and the additive is selected from 2,3,6,7,10,11-hexakis(n-octyloxy)triphenylene; while in Comparative Example 5, only the charge carrier transport material TCTA is used to prepare the charge carrier functional film. It shows that using a mixed solution including a charge carrier transport material and an additive to prepare the charge carrier functional film can effectively improve the charge carrier transport efficiency and is conducive to the preparation of an ordered light-emitting layer, thereby obtaining a light-emitting device with high efficiency, high brightness, and high stability.

[0189] In addition, in Comparative Example 6, only the additive T5DP-2,7 is used to prepare the charge carrier functional film, in Comparative Example 7, only the additive 2,3,6,7,10,11-hexakis(hexyloxy)triphenylene is used to prepare the charge carrier functional film, and in Comparative Example 8, the additive 2,3,6,7,10,11-hexakis(n-octyloxy)triphenylene is used, resulting in the thickness of the charge carrier functional film being difficult to reach the set target thickness, and further resulting in the driving voltages, EQEs, and luminance decay times of Comparative Examples 6 to 8 being worse than those of Comparative Example 5 and Examples 13 to 24.

[0190] An embodiment of the present application further provides a display device, and the display device includes the optoelectronic device as described above.

[0191] The optoelectronic device of this embodiment uses a mixed solution including a composite material and a solvent to prepare the charge carrier functional film, where the charge carrier transport material and the additive make the prepared charge carrier functional film have the characteristics of large-size, continuous, and layered crystal growth. Specifically, the molecules in the additive form a vertically oriented columnar structure through π-π interactions to epitaxially grow a large-size and continuous film on the substrate, and the surface flatness reaches the molecular level, which is conducive to the transport of charge carriers in the charge carrier functional film.

[0192] Since a highly oriented light-emitting layer is formed on the charge carrier functional film, the structure of the light-emitting layer and the charge carrier functional film has an orientation epitaxial relationship, thereby preparing a crystalline light-emitting layer. This embodiment uses the composite material to prepare the charge carrier functional film for the preparation of the crystalline light-emitting layer, realizing simple, efficient, and low-cost C-OLED preparation; and this embodiment uses the crystallization-induced fluorescence enhancement effect of the composite material to prepare the charge carrier functional film to realize a C-OLED device with high efficiency, high brightness, and high stability.

[0193] Obviously, the embodiments described above are only a part of the embodiments of this application, rather than all of them. The preferred embodiments of this application are shown in the accompanying drawings, but they do not limit the patent scope of this application. This application can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosed content of this application more thorough and comprehensive. Although this application has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing specific embodiments, or perform equivalent replacements on some of the technical features. Any equivalent structure that makes use of the content of this application's specification and drawings, directly or indirectly applied in other related technical fields, is equally within the scope of patent protection of this application.

Claims

1. A composite material, characterized in that, Comprising: A charge carrier transport material and an additive, the additive being selected from at least one of Formula I, II, III, IV, and V: Among them, R1 to R6 are each independently selected from O(CH2) n CH3, and one of COOCH3, and n is an integer selected from 1 to 7; R7 to R 25 is selected from one of Formula i, ii, iii, iv, v, vi, vii: Among them, R 26 to R 52 are each independently selected from hydrogen, deuterium, amino, halogen, hydroxyl, carboxyl, nitro, sulfonic acid group, aldehyde group, mercapto, cyano; C1-C20 hydrocarbon group, C1-C20 hydrocarbon oxy group, cycloalkyl group with 3 to 60 ring atoms, heterocycloalkyl group with 3 to 60 ring atoms, aryl group with 5 to 60 ring atoms, heteroaryl group with 5 to 60 ring atoms, aryloxy group with 5 to 60 ring atoms, heteroaryloxy group with 5 to 60 ring atoms which are unsubstituted or substituted by amino, halogen, hydroxyl, carboxyl, nitro, sulfonic acid group, aldehyde group, mercapto, cyano, and one or more combinations thereof, wherein the heteroatoms in the heteroaryl group or heteroaryloxy group are N, S, O, P, Si, and the number of heteroatoms is 1-20.

2. The composite material according to claim 1, characterized in that, When the additive is selected from Formula I, the structure of the additive is one of Formula VIII, IX, and X:

3. The composite material according to any one of claims 1 or 2, wherein The charge carrier transport material is selected from at least one of PVK, CDBP, mCBP, CBP, mCP, TCTA, and NPB; and / or The mass ratio of the charge carrier transport material to the additive is (60-90):(40-10).

4. A method for preparing a thin film, characterized in that, Comprising: Providing a solvent and the composite material according to any one of claims 1 to 3; Mixing the solvent and the composite material to obtain a mixed solution; Depositing the mixed solution to obtain the thin film.

5. The method for preparing a thin film according to claim 4, wherein ,, The step of depositing the mixed solution to obtain the thin film specifically comprises: Annealing the mixed solution, wherein the annealing temperature is 200-260 °C.

6. The method for preparing a thin film according to claim 4 or 5, characterized in that, The solvent is selected from methyl benzoate, toluene, xylene, chlorobenzene, chloroform, tetrahydrofuran, acetonitrile, and dichloromethane; and / or The concentration of the composite material in the mixed solution is 5-15 mg / ml.

7. A film, characterized in that, The thin film is prepared by the thin film preparation method according to any one of claims 4 to 6, or comprises the composite material according to any one of claims 1 to 3.

8. An optoelectronic device, characterized in that, Comprising a first electrode, a charge carrier functional thin film, a light emitting layer, and a second electrode which are stacked; The material of the charge carrier functional thin film comprises the composite material according to any one of claims 1 to 3, or the charge carrier functional thin film is the thin film according to claim 7.

9. The optoelectronic device according to claim 8, characterized in that, The first electrode and the second electrode are each selected from one or more of a metal electrode, a silicon carbide electrode, a doped or undoped metal oxide electrode, and a composite electrode; wherein, the material of the metal electrode is selected from at least one of Al, Ag, Cu, Mo, Au, Ba, Ca, and Mg; the material of the silicon carbide electrode is selected from at least one of silicon, graphite, carbon nanotubes, graphene, and carbon fiber; the material of the doped or undoped metal oxide electrode is selected from at least one of ITO, FTO, ATO, AZO, GZO, IZO, MZO, and AMO; the material of the composite electrode is selected from at least one of 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, TiO2 / Ag / TiO2, and TiO2 / Al / TiO2; and / or A hole injection layer is provided between the first electrode and the carrier functional thin film, and the material of the hole injection layer includes at least one of TFB, CuPc, PVK, Poly-TPD, PFB, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, T·APC, MCC, F4-TCNQ, HATCN, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, polyaniline, transition metal oxides, transition metal sulfides, transition metal stannides, doped graphene, undoped graphene, and C60; and / or The material of the light-emitting layer includes at least one of PABBP, PATPA, mPAC, PAC, 4,4'-bis(N-carbazolyl)-1,1'-biphenyl: tris[2-(p-tolyl)pyridine-C2,N]iridium(III), 4,4',4''-tris(carbazol-9-yl)triphenylamine: tris[2-(p-tolyl)pyridine-C2,N]iridium, diaryl anthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent material, TTPX fluorescent material, TBRb fluorescent material, and DBP fluorescent material, polyacetylene and its derivatives, poly(p-phenylene) and its derivatives, polythiophene and its derivatives, polyfluorene and its derivatives; and / or An electron functional layer is provided between the second electrode and the light-emitting layer. The electron functional layer includes an electron transport layer and / or an electron injection layer. When the electron functional layer includes an electron injection layer and an electron transport layer, the electron injection layer is disposed adjacent to the second electrode, and the electron transport layer is disposed adjacent to the light-emitting layer; the material of the electron transport layer is selected from at least one of doped or undoped metal oxides and organic electron transport materials; the doped or undoped metal oxides are selected from at least one of doped or undoped zinc oxide, tin oxide, titanium oxide, and zirconium oxide, and the doped elements include at least one of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, and gadolinium; the organic electron transport materials are selected from [6,6]-phenyl C71 butyric acid methyl ester, [6,6]-phenyl C61 butyric acid methyl ester, organic fullerene materials, 2-ethyl-1-(4-(10-(2-naphthyl)-9-anthryl)phenyl)-1H-benzimidazole, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, 3,3'-[5'-[3-(3-pyridyl)phenyl], 4,6-bis(3,5-bis(3-pyridyl)phenyl)-2-methylpyrimidine, phenylylpyridyl beryllium, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene(, 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole, 1,3,5-tris[(3-pyridyl)-3-phenyl]benzene, tris-(8-hydroxyquinoline) aluminum, 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline, 4,7-diphenyl-1,10-phenanthroline, poly[(9,9-bis(3'-((N,N-dimethyl)-N-ethylammonium)-propyl)-2,7-fluorene)-2,7-(9,9-dioctylfluorene)] dibromide, poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-2,7-(9,9-dioctylfluorene)], 2,7-bis(diphenylphosphino)-9,9'-spirobi[fluorene], Alq3, TSPO1, TmPyPB, PBD, Beq2, TAZ, SPPO13, etc.; The material of the electron injection layer is selected from at least one of Yb, yttrium fluoride, Li, LiF, NaF, CeF, CsCO3, Cs, KBH4, or KH.

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

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