Light-emitting material composition and organic electroluminescent device, method for preparing the same, and electronic device

Abstract

The application relates to the field of organic materials, and provides a luminescent material composition, an organic electroluminescent device, a preparation method of the organic electroluminescent device and an electronic device. The luminescent material composition comprises an organic luminescent material, a surfactant and a solvent, wherein the organic luminescent material comprises at least one of phenanthroimidazole hot exciton materials with a structure shown in formula I, the luminescent material composition can form an organic luminescent layer of an organic electroluminescent device through a solution processing mode, and the performance of the device is improved.

Description

Technical Field

[0001] This application relates to the field of organic materials, and in particular to a luminescent material composition, an organic electroluminescent device, a method for preparing the same, and an electronic device thereof. Background Technology

[0002] Over the past few decades, organic light-emitting diodes (OLEDs) have garnered significant attention due to their potential applications in solid-state lighting and flat panel displays. There are generally two methods for fabricating OLEDs: for small-molecule materials used in the device, the standard method is vacuum evaporation to form the corresponding functional layers; for polymer materials, simple solution processing techniques (such as spin coating and inkjet printing) can be used, followed by solvent drying to form the corresponding functional layers. Small molecules have advantages such as ease of synthesis and purification, and vacuum evaporation can produce small-molecule devices with complex structures and excellent performance. However, vacuum evaporation requires a high-vacuum and thermal evaporation environment, which undoubtedly increases the complexity of the OLED fabrication process, resulting in a material utilization rate of only around 20%. Solution processing is an effective method to improve process efficiency and reduce production costs. For example, inkjet printing can be effectively used to fabricate large-area, high-resolution full-color flat panel displays. Compared to vacuum evaporation, spin coating for OLED fabrication offers advantages such as lower fabrication costs, simpler processes, mass production capabilities, and precise control of doping ratios.

[0003] Currently, many small organic molecule materials with conjugated structures and rigidity are used in the functional layers of OLED devices, giving the devices excellent properties in terms of lifetime, efficiency, color purity, and carrier mobility. However, due to strong intermolecular forces, they are not easily soluble or even insoluble in organic solvents, making them suitable only for vacuum evaporation. Organic small molecule materials are relatively expensive, and vacuum evaporation has low material utilization, resulting in excessively high device manufacturing costs. Therefore, it is necessary to develop functional layer material compositions containing organic small molecule materials that can be solution-processed. Summary of the Invention

[0004] The purpose of this application is to provide a luminescent material composition, an organic electroluminescent device, a method for preparing the same, and an electronic device thereof. The luminescent material composition can be used to form the organic light-emitting layer of the organic electroluminescent device through solution processing, thereby improving the device's performance.

[0005] In a first aspect, this application provides a luminescent material composition comprising an organic luminescent material, a surfactant, and a solvent, wherein the organic luminescent material comprises at least one phenanthreneimidazole-based thermal exciton material, and the structure of the phenanthreneimidazole-based thermal exciton material is shown in Formula I:

[0006]

[0007] In Formula I, L is selected from single bonds, substituted or unsubstituted aryl groups with 6-25 carbon atoms, or substituted or unsubstituted heteroaryl groups with 5-25 carbon atoms.

[0008] Ar is selected from substituted or unsubstituted aryl, alkenyl, heteroaryl with 5-30 carbon atoms, or substituted or unsubstituted aromatic amino groups with 12-30 carbon atoms, either substituted or unsubstituted.

[0009] In Ar and L, the substituents are independently deuterium, halogen, alkyl with 1-4 carbon atoms, alkoxy with 1-4 carbon atoms, aryl with 6-12 carbon atoms, or heteroaryl with 5-12 carbon atoms.

[0010] R is selected from F, CN or alkyl groups having 1-5 carbon atoms, and n represents the number of R, where n is 0, 1, 2, 3, 4 or 5;

[0011] The surfactants include fluorocarbon surfactants.

[0012] Secondly, this application provides an organic electroluminescent device, comprising: an anode and a cathode disposed opposite to each other, and an organic light-emitting layer disposed between the anode and the cathode, wherein the raw material of the organic light-emitting layer comprises the light-emitting material composition; or, the organic light-emitting layer is formed of the light-emitting material composition.

[0013] Thirdly, this application provides a method for preparing an organic electroluminescent device, the method comprising: sequentially stacking an anode, an organic light-emitting layer, and a cathode; or sequentially stacking a cathode, an organic light-emitting layer, and an anode; wherein the organic light-emitting layer is prepared by using the light-emitting material composition described in the first aspect of this application and by a solution method.

[0014] Fourthly, this application provides an electronic device, including the organic electroluminescent device described in the second aspect of this application or the organic electroluminescent device prepared by the preparation method described in the third aspect.

[0015] In this application, a specific surfactant is introduced into a solution containing a phenanthrimidazole-based thermal exciton material (as the organic light-emitting material of the light-emitting layer) as shown in Formula I. This allows the organic compound to form a stable aggregated colloidal structure in the solution, thereby enabling the light-emitting material composition of this application to form an organic light-emitting layer through solution processing. This method is expected to produce high-performance OLED devices that can be processed over large areas and mass-produced using solution processing. Furthermore, forming the organic light-emitting layer of the OLED device from the aforementioned light-emitting material composition can improve the luminous efficiency and lifespan of the OLED device and reduce the driving voltage of the device.

[0016] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of an organic electroluminescent device according to one embodiment of this application;

[0018] Figure 2 The current efficiency diagrams for the organic electroluminescent devices prepared in Examples 1-6 and Comparative Examples 1-2 at different current densities are shown.

[0019] Explanation of reference numerals in the attached figures

[0020] 100: Organic electroluminescent device; 1: Anode; 2: Hole injection layer; 3: Hole transport layer

[0021] 4: Organic light-emitting layer; 5: Electron transport layer; 6: Electron injection layer; 7: Cathode. Detailed Implementation

[0022] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[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 this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. "A plurality of" means more than two, such as 2, 3, 4, 5, 6, etc.

[0024] In this application, the term "substituted or unsubstituted" means that the functional group described after the term may or may not have substituents. For example, "substituted or unsubstituted phenyl" refers to a phenyl with substituents or an unsubstituted phenyl. The number of substituents can be one or more, and substituents include at least one of deuterium (D), halogens, alkyl groups, aryl groups, and heteroaryl groups. It should be understood that when the number of substituents is greater than one, the substituents can be the same or different; when the functional group has substituents, the number of carbon atoms refers to the total number of carbon atoms of the functional group and its substituents. For example, in Formula I, when Ar is a methyl-substituted phenyl, the total number of carbon atoms in Ar is 7, that is, Ar is a methyl-substituted phenyl with 7 carbon atoms.

[0025] In this application, aryl refers to an aromatic hydrocarbon group derived from an aromatic ring compound by losing one hydrogen atom. Aryl can be a monocyclic aryl (such as phenyl), a fused-ring aryl (such as naphthyl), two or more monocyclic aryl groups (such as biphenyl) conjugated by carbon-carbon bonds, a monocyclic aryl and a fused-ring aryl group conjugated by carbon-carbon bonds, or two or more fused-ring aryl groups conjugated by carbon-carbon bonds. Specific examples of aryl include, but are not limited to, phenyl, naphthyl, anthracene, phenanthryl, biphenyl, terphenyl, benzo[9,10]phenanthryl, pyrene, benzofluoranthracene, etc. Benzyl, fluorene, etc.

[0026] In this application, a heteroaryl group refers to a group formed by replacing at least one carbon atom with a heteroatom on the basis of an aryl group. The heteroatom can be at least one of B, O, N, P, Si, Se, and S. The number of heteroatoms in a heteroaryl group can be 1, 2, 3, 4, 5, or more. A heteroaryl group can be a monocyclic heteroaryl or a fused-ring heteroaryl. Specific examples of heteroaryl groups include, but are not limited to, thienyl, furanyl, pyrrolyl, imidazolyl, thiazolyl, oxazolyl, oxadiazolyl, triazolyl, pyridyl, triazinyl, acridinel, pyridazinyl, quinolinyl, quinazolinyl, quinoxazinyl, phenothiazinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, isoquinolinyl, indolyl, carbazole, benzoxazolyl, benzimidazolyl, benzothiazolyl, benzocarbazole, benzothiophene, dibenzothiophene, thiophenothiophene, benzofuranyl, phenanthrololinyl, isoxazolyl, thiazolyl, phenothiazinyl, phenothiazinyl, dibenzo-p-dioxinyl, quinazolinone, benzothiazolyl, benzotriazolyl, thianthyl, phenothiazinyl, phenothiazinyl, etc.

[0027] In this application, the alkyl group used as a substituent includes alkyl groups having 1 to 4 carbon atoms, such as 1, 2, 3, or 4 carbon atoms. Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, 1-butyl (n-Bu, n-butyl, -CH2CH2CH2CH3), 2-methyl-1-propyl (i-Bu, i-butyl, -CH2CH(CH3)2), 2-butyl (s-Bu, s-butyl, -CH(CH3)CH2CH3), and 2-methyl-2-propyl (t-Bu, t-butyl, -C(CH3)3, tert-butyl).

[0028] In this application, the substituted alkoxy group includes alkoxy groups having 1 to 4 carbon atoms, such as 1, 2, 3, or 4 carbon atoms. Examples of alkoxy groups include, but are not limited to, methoxy (-O-CH3 or -OMe), ethoxy (-O-CH2CH3 or -OEt), and tert-butoxy (OC(CH3)3 or -OtBu).

[0029] In this application, the halogens used as substituents include chlorine, fluorine, bromine, and iodine.

[0030] In this application, the aryl group used as a substituent can have 6-12 carbon atoms, for example, 6, 10, or 12. Examples of aryl groups used as substituents include, but are not limited to, phenyl, naphthyl, and biphenyl.

[0031] In this application, the number of carbon atoms in the heteroaryl group used as a substituent can be 5-12, for example 5, 6, 10, or 12. Examples of heteroaryl groups used as substituents include, but are not limited to, pyridinyl, pyrimidinyl, quinolinyl, piperazineyl, and carbazoleyl.

[0032] In this application, The term "linking bond" refers to a non-positioned linking bond that extends from the ring system. This indicates that one end of the linker can connect to any position in the ring system it traverses, while the other end connects to the rest of the molecule. For example, as shown in equation (Z), the naphthyl group is connected to other positions in the molecule via a non-positional linker extending from the middle of one side of the benzene ring, representing any of the connection methods shown in equations (Z-1) and (Z-2):

[0033]

[0034] In this application, a non-orienting substituent refers to a substituent connected by a single bond extending from the center of the ring system, indicating that the substituent can be attached to any possible position in the ring system. For example, as shown in equation (E), substituent R is connected to the naphthalene ring by a non-orienting linking bond, which means that it includes any of the possible connection methods shown in equations (E-1) to (E-14):

[0035]

[0036] In this application, the number of carbon atoms in the substituted or unsubstituted aryl group can be 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30.

[0037] In this application, the number of carbon atoms in the substituted or unsubstituted heteroaryl group can be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30.

[0038] In this application, the aromatic amino group includes diaromatic amino group and triaromatic amino group.

[0039] The inventors of this application discovered that the phenanthrimidazole-based thermal exciton material represented by Formula I can be stably dispersed in a solvent at a high concentration in the presence of fluorocarbon surfactants, forming a stable aggregated colloidal structure. This avoids particle precipitation during spin coating, preventing uneven film thickness or coating failure due to the sol not spreading evenly on the substrate. In the fabrication of organic electroluminescent devices, a functional layer of appropriate thickness can be formed through solution processing, improving the device's luminous efficiency and other properties. Based on this discovery, this application proposes a luminescent material composition, its application, and an organic electroluminescent device and electronic device.

[0040] A first aspect of this application provides a luminescent material composition comprising an organic luminescent material, a surfactant, and a solvent.

[0041] In this application, the organic light-emitting material includes at least one phenanthreneimidazole-based thermal exciton material, the structure of which is shown in Formula I:

[0042]

[0043] Wherein, L is selected from single bonds, substituted or unsubstituted aryl groups with 6-25 carbon atoms, or substituted or unsubstituted heteroaryl groups with 5-25 carbon atoms;

[0044] Ar is selected from substituted or unsubstituted aryl, alkenyl, heteroaryl with 5-30 carbon atoms, or substituted or unsubstituted aromatic amino groups with 12-30 carbon atoms, either substituted or unsubstituted.

[0045] In Ar and L, the substituents are independently D, halogen, alkyl with 1-4 carbon atoms, alkoxy with 1-4 carbon atoms, aryl with 6-12 carbon atoms, or heteroaryl with 5-12 carbon atoms.

[0046] R is selected from F, CN or alkyl groups having 1-5 carbon atoms, and n represents the number of R, where n is 0, 1, 2, 3, 4 or 5.

[0047] In some embodiments, the structure of the organic compound is shown in Formula I-1 or Formula I-2:

[0048]

[0049] In some embodiments, Ar is a substituted or unsubstituted aryl, alkenyl, heteroaryl with 12-25 carbon atoms, or a substituted or unsubstituted triarylamine with 12-28 carbon atoms.

[0050] In one embodiment, Ar is selected from any one of the following groups: substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted anthracene, substituted or unsubstituted carbazolyl, substituted or unsubstituted fluorenyl, substituted or substituted dihydroacridyl, substituted or unsubstituted benzimidazolyl; wherein the substituted substituent in Ar is independently D, F, methyl, ethyl, n-propyl, isopropyl, tert-butyl, methoxy, ethoxy, phenyl, naphthyl, biphenyl or carbazolyl.

[0051] In another embodiment, Ar is a group W that is substituted or unsubstituted by one or more substituents V1, wherein the structure of the unsubstituted group W is shown in Formula A:

[0052]

[0053] Wherein, L1 is a single bond or a phenylene group, and Ar1 and Ar2 are the same or different, and each is independently a phenyl, naphthyl or biphenyl group;

[0054] Each substituent V1 is independently deuterium, fluorine, methyl, ethyl, n-propyl, isopropyl, tert-butyl, methoxy, ethoxy, phenyl, naphthyl, or biphenyl.

[0055] Optionally, in Formula I, Ar is any one of the following groups:

[0056]

[0057] Further, optionally, Ar is any one of the following groups:

[0058]

[0059] In some embodiments, L is a single bond or any of the following groups:

[0060]

[0061] Optionally, L is a single bond or any of the following groups:

[0062]

[0063] Optionally, R is selected from F, CN, methyl, ethyl, n-propyl, isopropyl, or tert-butyl.

[0064] In some embodiments, the organic light-emitting material includes at least one of the following phenanthrimidazole thermal exciton compounds:

[0065]

[0066]

[0067] In some embodiments, the surfactant includes at least one of potassium perfluorooctyl sulfonate, perfluorooctyl sulfonamide, and N-ethyl perfluorooctyl sulfonamide.

[0068] In this application, the solvent may include various polar solvents used in solution processing. In some embodiments, the solvent includes at least one selected from chloroform, toluene, chlorobenzene, methyl benzoate, and xylene.

[0069] In some embodiments, the mass ratio of the surfactant to the organic light-emitting material in the luminescent material composition is (5-20):(95-80), for example, 5:95, 6:94, 7:93, 10:90, 11:89, 12:88, 13:87, 14:86, 15:85, 16:84, 17:83, 18:82, 19:81 or 20:80.

[0070] In some embodiments, the luminescent material composition is prepared by mixing a dispersion of the organic luminescent material and a solution of the surfactant; wherein the concentration of the organic luminescent material in the dispersion is 10-35 mg / mL, and the concentration of the surfactant in the solution is 5-25 mg / mL.

[0071] Optionally, the luminescent material composition is prepared by a method comprising the following steps:

[0072] After mixing the organic light-emitting material and the solvent, the mixture is ultrasonically treated for 10-30 minutes. During the ultrasonic treatment, a solution of the surfactant is gradually added to prepare an ink of a certain concentration.

[0073] In the luminescent material composition of this application, the presence of the surfactant allows the organic luminescent material to be uniformly dispersed in a solvent at a high concentration, resulting in an ink suitable for solution processing. The luminescent material composition is particularly suitable for spin coating to form the organic luminescent layer of an organic electroluminescent device. Specifically, the introduction of the surfactant increases the concentration of the organic luminescent material in the ink. In the organic luminescent layer formed by drying the luminescent material composition (ink), the organic luminescent material can be more uniformly distributed throughout the film layer and achieve the target luminescent layer thickness. This avoids the excitons generated by carrier recombination being quenched due to the metal electrode / organic layer interface if the luminescent layer is too thin, thereby improving the luminous efficiency of the device.

[0074] Accordingly, a second aspect of this application provides an organic electroluminescent device, comprising: an anode and a cathode disposed opposite to each other; and an organic light-emitting layer disposed between the anode and the cathode, wherein the raw material of the organic light-emitting layer comprises the light-emitting material composition; or, the organic light-emitting layer is formed from the light-emitting material composition. The light-emitting material composition can be formed into a film using a solution method (such as spin coating, inkjet printing, etc.).

[0075] This application does not particularly limit the material of the anode, and it can be any anode material capable of transporting holes. Anode materials include, for example, one or a combination of metals, metal oxides, and conductive polymers. In some embodiments, the anode material includes at least one of indium tin oxide (ITO) and indium zinc oxide (IZO).

[0076] This application does not specifically limit the material of the cathode; it can be any cathode material capable of transporting electrons. The cathode material may include metals, such as one or more of magnesium (Mg), calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum (Al), silver (Ag), tin, and lead, or an alloy of at least two of these metals. In some embodiments, the cathode material includes at least one of Li, Al, Ag, and Mg.

[0077] In some embodiments, the organic electroluminescent device further includes a hole functional layer disposed between the anode and the organic light-emitting layer, and an electron functional layer disposed between the cathode and the organic light-emitting layer. The hole functional layer includes a hole injection layer and / or a hole transport layer, and the electron functional layer includes an electron injection layer and / or an electron transport layer.

[0078] In some implementations, such as Figure 1 As shown, the organic electroluminescent device 100 includes an anode 1, a hole injection layer 2, a hole transport layer 3, an organic light-emitting layer 4, an electron transport layer 5, an electron injection layer 6, and a cathode 7, which are stacked sequentially. The organic light-emitting layer 4 is formed from the light-emitting material composition.

[0079] This application does not impose any particular limitation on the material of the hole injection layer 2, and the material can be selected with reference to the prior art. In one embodiment, the material of the hole injection layer 2 includes polyethylene dioxythiophene-poly(styrene sulfonate) (PEDOT:PSS, CAS No.: 155090-83-8).

[0080] In this application, the hole transport material of the hole transport layer 3 can be selected from various electron-rich organic materials that are conducive to hole transport, such as aromatic amine derivatives, carbazole derivatives, etc. In some embodiments, the hole transport material includes at least one of PVK (poly(9-vinylcarbazole), CAS No.: 25067-59-8), CDBP (CAS No.: 120260-01-7), mCBP (CAS No.: 342638-54-4), CBP (CAS No.: 58328-31-7), mCP (CAS No.: 550378-78-4), TCTA (CAS No.: 139092-78-7), and NPB (CAS No.: 123847-85-8).

[0081] In one embodiment, the hole transport material is PVK.

[0082] In this application, the electron transport material of the electron transport layer 5 may include at least one of aluminum 8-hydroxyquinoline (AlQ), PBD (CAS No.: 852-38-0), and SPPO13 (CAS No.: 1234510-13-4).

[0083] In one embodiment, the electron transport material is SPPO13.

[0084] In this application, the electron injection layer 6 can enhance the ability of the cathode 7 to inject electrons into the electron transport layer 5. In one embodiment, the material of the electron injection layer is LiQ or LiF.

[0085] In some embodiments, the organic light-emitting layer 4 is formed by spin-coating the luminescent material composition onto the hole transport layer 5 and then drying it. The drying temperature can be 90-130°C, and the drying time can be 20-60 minutes.

[0086] A third aspect of this application provides a method for fabricating an organic electroluminescent device, the method comprising:

[0087] An anode, an organic light-emitting layer, and a cathode are sequentially stacked; or, a cathode, an organic light-emitting layer, and an anode are sequentially stacked. The organic light-emitting layer is prepared using the luminescent material composition described in the first aspect of this application via a solution method. The solution method may include one or more of the following: spin coating, printing, inkjet printing, blade coating, dip coating, immersion coating, spraying, roller coating, casting, slot coating, and strip coating. This method may also include a drying process to ultimately form the desired organic light-emitting layer.

[0088] The preparation method described in this application aims to illustrate that the organic light-emitting layer can be formed by solution processing using the light-emitting material composition. Therefore, the method for forming other functional layers of the organic electroluminescent device is not particularly limited; for example, it may include steps such as solution processing or vapor deposition to form the anode, cathode, hole functional layer, and electron functional layer. The anode, cathode, hole functional layer, and electron functional layer are described as in the second aspect of this application. The organic electroluminescent device described in the second aspect of this application can be prepared using the aforementioned preparation method.

[0089] A fourth aspect of this application provides an electronic device including the aforementioned organic electroluminescent device. The electronic device may be a display device, a lighting device, an optical communication device, or other types of electronic devices, including, but not limited to, computer screens, mobile phone screens, televisions, electronic paper, emergency lighting, and optical modules.

[0090] The following specific preparation examples illustrate this application.

[0091] In the following preparation examples and comparative examples,

[0092] PEDOT: PSS was purchased from Xi'an Baolai Optoelectronic Materials Technology Co., Ltd., product number 300030;

[0093] PVK was purchased from Xi'an Baolai Optoelectronic Materials Technology Co., Ltd., product number 302005;

[0094] Perfluorooctylsulfonamide (CAS No.: 754-91-6) was purchased from Wuhan Rongcan Biotechnology Co., Ltd.

[0095] The preparation examples are used to illustrate the luminescent material composition and its preparation method of this application.

[0096] Preparation Examples 1-7 and Comparative Examples 1-2

[0097] Organic light-emitting materials (OLEDs) and toluene were mixed to obtain an OLED dispersion. The dispersion was then sonicated for 20 minutes. During sonication, a toluene solution containing a surfactant was gradually added to prepare OLED compositions EM-1 to EM-7 and EM-D1 and EM-D2. The components and their amounts are shown in Table 1.

[0098] Table 1

[0099]

[0100] Example 1: Fabrication of Organic Electroluminescent Devices

[0101] First, the ITO substrate (50nm thick) was cleaned in the following order: ultrasonication with 5wt% KOH solution for 15min, ultrasonication with pure water for 15min, ultrasonication with isopropanol for 15min, and drying in an oven for 1h; then the substrate was transferred to a UV-OZONE device for surface treatment for 15min, and immediately transferred to a glove box after treatment.

[0102] PEDOT:PSS was spin-coated onto a clean ITO substrate and dried at 140°C for 30 min to form a hole injection layer with a thickness of 30 nm.

[0103] A toluene solution of PVK with a concentration of 6 mg / mL was spin-coated onto the hole injection layer and dried at 125 °C for 30 min to form a hole transport layer with a thickness of 25 nm.

[0104] On the hole transport layer, the composition EM-1 of Example 1 was spin-coated and dried at 100°C for 30 min to form an organic light-emitting layer with a thickness of 25 nm.

[0105] SPPO13 was vacuum-deposited on the organic light-emitting layer to form an electron transport layer with a thickness of 30 nm.

[0106] On the electron transport layer, LiF is vacuum-deposited to form an electron injection layer with a thickness of 1 nm;

[0107] Al is vacuum-deposited onto the electron-injected layer to form a cathode with a thickness of 100 nm.

[0108] Finally, the device is encapsulated with epoxy resin to complete the manufacturing of the organic electroluminescent device.

[0109] Examples 2-7

[0110] Organic electroluminescent devices were prepared according to the method of Example 1, except that EM-1 was replaced by compositions EM-2 to EM-7 respectively when preparing the organic light-emitting layer.

[0111] Comparative Examples 1-2

[0112] Organic electroluminescent devices were prepared according to the method of Example 1, except that EM-1 was replaced by compositions EM-D1 and EM-D2 respectively when preparing the organic light-emitting layer.

[0113] The performance of the organic electroluminescent devices prepared in Examples 1-7 and Comparative Examples 1-2 was analyzed. Specifically, at 10 mA / cm², the performance of the devices was... 2 The IVL performance (drive voltage, efficiency, and chromatic coordinates) of the device was tested at a current density of 1000 Cd / m. 2 The T95 lifespan of the device was tested under the initial brightness conditions, and the results are shown in Table 1.

[0114] Table 2

[0115]

[0116] T 95 Lifetime (h) @ 1000cd / m 2 The device has an initial brightness of 1000 Cd / m². 2 The light continues to illuminate until the brightness decreases to 95% of the initial brightness (950 Cd / m²). 2 The time elapsed during ( ).

[0117] Examples 1-7 use luminescent material compositions containing the surfactant described in this application to prepare organic electroluminescent devices. Comparative Examples 1 and 2 use luminescent materials without surfactants to prepare organic electroluminescent devices. Referring to Tables 1 and 2, it can be seen that because PABPP has a high degree of conjugation, strong rigidity, and low solubility, it can only dissolve in chloroform at approximately 1 mg / mL (Comparative Example 1). In Comparative Example 2, the luminescent material in a toluene solution with 2 mg / mL of luminescent material without surfactant is not completely dissolved. After filtration, the solution concentration cannot reach the set target concentration, only reaching the saturation concentration. In Comparative Examples 1-2, due to the low concentration of luminescent material in the ink, it is very difficult to prepare a thin film using spin coating, making it difficult to achieve the thickness of the organic luminescent layer prepared in the examples; its thickness is only between 5-7 nm. Furthermore, as shown in Examples 1-4 and 6, when the doping ratio of surfactant and organic luminescent material is the same, mixing different luminescent material dispersions and different surfactant solutions results in different micelle concentrations in the ink, affecting the content and distribution of organic luminescent material in the formed organic luminescent layer, thus obtaining luminescent devices with different performance. Figure 2 The current efficiency of the devices in Examples 1-6 and Comparative Examples 1-2 at different current densities was compared. Figure 2 It can be seen that the current efficiency of the devices in Examples 1-6 is significantly higher than that of the devices in Comparative Examples 1-2.

[0118] In summary, the luminescent material composition of this application can be used to form the organic light-emitting layer of an organic electroluminescent device through solution processing, which reduces the cost of device fabrication while ensuring that the device has excellent overall performance.

[0119] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0120] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A luminescent material composition, characterized in that, The luminescent material composition comprises an organic luminescent material, a surfactant, and a solvent, wherein the organic luminescent material includes at least one phenanthreneimidazole-based thermal exciton material, and the structure of the phenanthreneimidazole-based thermal exciton material is shown in Formula I: In Formula I, L is a single bond or any of the following groups: ； Ar is selected from substituted or unsubstituted aryl, alkenyl, heteroaryl with 5-30 carbon atoms, or substituted or unsubstituted aromatic amino groups with 12-30 carbon atoms, either substituted or unsubstituted. In Ar, the substituents are independently D, halogen, alkyl with 1-4 carbon atoms, alkoxy with 1-4 carbon atoms, aryl with 6-12 carbon atoms, or heteroaryl with 5-12 carbon atoms. R is selected from F, CN or alkyl groups having 1-5 carbon atoms, and n represents the number of R, where n is 0, 1, 2, 3, 4 or 5; The surfactant includes at least one of potassium perfluoron-octyl sulfonate, perfluoron-octyl sulfonamide, and N-ethyl perfluoron-octyl sulfonamide. The solvent includes at least one of chloroform, toluene, chlorobenzene, methyl benzoate, and xylene.

2. The luminescent material composition according to claim 1, characterized in that, The structure of the organic compound is shown in Formula I-1 or Formula I-2: 。 3. The luminescent material composition according to claim 1, characterized in that, Ar is a substituted or unsubstituted aryl, alkenyl, heteroaryl with substituted or unsubstituted carbon atoms of 12-25, or a substituted or unsubstituted triarylamine with substituted or unsubstituted carbon atoms of 12-28.

4. The luminescent material composition according to claim 3, characterized in that, Ar is selected from any one of the following groups: substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted anthraquinone, substituted or unsubstituted carbazole, substituted or unsubstituted fluorenyl, substituted or substituted dihydroacrylyl, substituted or unsubstituted benzimidazolyl; wherein the substituted substituent in Ar is independently D, F, methyl, ethyl, n-propyl, isopropyl, tert-butyl, methoxy, ethoxy, phenyl, naphthyl, biphenyl or carbazole; Alternatively, Ar is a group W that is substituted or unsubstituted by one or more substituents V1, wherein the structure of the unsubstituted group W is shown in formula A: Wherein, L1 is a single bond or a phenylene group, Ar1 and Ar2 are the same or different, and each is independently phenyl, naphthyl or biphenyl; each substituent V1 is independently deuterium, fluorine, methyl, ethyl, n-propyl, isopropyl, tert-butyl, methoxy, ethoxy, phenyl, naphthyl or biphenyl.

5. The luminescent material composition according to claim 1, characterized in that, In Formula I, Ar is any one of the following groups: 。 6. The luminescent material composition according to claim 5, characterized in that, In Formula I, Ar is any one of the following groups: 。 7. The luminescent material composition according to claim 1, characterized in that, In Formula I, L is a single bond or any of the following groups: 。 8. The luminescent material composition according to claim 1, characterized in that, The organic light-emitting material includes at least one of the following phenanthrimidazole thermal exciton compounds: 。 9. The luminescent material composition according to any one of claims 1-8, characterized in that, In the luminescent material composition, the mass ratio of the surfactant to the organic luminescent material is (5-20):(95-80).

10. The luminescent material composition according to claim 9, characterized in that, The luminescent material composition is prepared by mixing a dispersion of the organic luminescent material and a solution of the surfactant; wherein the concentration of the organic luminescent material in the dispersion is 10-35 mg / mL, and the concentration of the surfactant in the solution is 5-25 mg / mL.

11. An organic electroluminescent device, characterized in that, include: Anode and cathode are set opposite to each other; as well as An organic light-emitting layer disposed between the anode and the cathode, wherein the raw material of the organic light-emitting layer comprises the light-emitting material composition according to any one of claims 1-10; or, the organic light-emitting layer is formed from the light-emitting material composition according to any one of claims 1-10.

12. A method for fabricating an organic electroluminescent device, characterized in that, include: The anode, organic light-emitting layer, and cathode are sequentially stacked; or, the cathode, organic light-emitting layer, and anode are sequentially stacked. The organic light-emitting layer is prepared by solution method using the light-emitting material composition according to any one of claims 1-10.

13. An electronic device, characterized in that, This includes the organic electroluminescent device according to claim 11, or the organic electroluminescent device prepared by the preparation method according to claim 12.

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