Organic light-emitting material, organic electroluminescent device and preparation thereof

Abstract

The present application relates to the field of photoelectric technology, especially to organic light-emitting material, organic electroluminescent device and preparation thereof. The organic light-emitting material based on acephenanthrylene derivative and the organic electroluminescent device thereof, the material is fused through benzene ring, ensures that the excited state has high oscillator strength, is conducive to radiation transition, and the rigid fused ring structure can effectively inhibit intramolecular vibration, helps to inhibit the non-radiative transition behavior of the excited state and obtain high photoluminescence efficiency, in addition, the molecule can form intermolecular charge transfer aggregate to reduce the non-adiabatic coupling of electrons, so as to realize low non-radiative transition rate, further improve the photoluminescence efficiency, and also can stabilize the excited state energy, can be further applied to organic electroluminescent device, realizes high electroluminescence efficiency.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic technology, and in particular to organic light-emitting materials, organic electroluminescent devices, and their fabrication. Background Technology

[0002] Organic light-emitting diode (OLED) technology is an active light-emitting technology that uses organic semiconductor thin films under an applied electric field. Due to its numerous advantages, including being all-solid-state, having a wide viewing angle, fast response, being thin and flexible, having high brightness, and low power consumption, it has received high attention from academia and industry and is now widely used in flat panel displays, wearable devices, solid-state lighting, and other fields. Organic light-emitting materials, as a key part of the OLED display technology industry chain, are one of the key technological barriers. In comparison, the development of deep red light-emitting materials, especially near-infrared light-emitting materials, is relatively lagging behind. However, deep red / near-infrared light-emitting materials play an irreplaceable role in emerging fields such as security displays, night vision devices, information security storage, and optical communications. Therefore, in recent years, the development of novel, high-efficiency deep red / near-infrared light-emitting materials has become a hot topic and a challenge in the field of organic optoelectronics.

[0003] Based on their light-emitting mechanisms, OLED luminescent materials are mainly classified into traditional fluorescent materials, phosphorescent materials, and thermally activated delayed fluorescence materials. Currently, the vast majority of materials used in OLED luminescent layers are traditional fluorescent materials. According to quantum statistical laws, only 25% of singlet excitons can be utilized, resulting in an external quantum efficiency generally below 5%, severely impacting their luminescent performance. Phosphorescent materials composed of coordinating heavy metals such as iridium, platinum, and osmium have achieved higher luminescent efficiencies (external quantum efficiency exceeding 20%), but their large spectral half-width (FWHM) (greater than 60 nm) and high material cost limit their applications. Achieving efficient utilization of triplet excitons in purely organic fluorescent materials to realize high-efficiency fluorescent devices is a key research focus in the OLED field.

[0004] In the past decade, replacing phosphorescent materials with thermally activated delayed fluorescence materials that do not contain precious metals has been a relatively ideal approach. These materials mainly include carbazole and its derivatives, triazine and its derivatives, pyrimidine and its derivatives, pyridine and its derivatives, and acenaphthene (US18059410, US17937348, CN201911205731.9, CN202011480586.8, WOCN21101705, CN201810315618.5). Furthermore, the design of deep-red / near-infrared metal complex materials requires both a relatively small molecular weight and the presence of large conjugated groups, which limits the molecular design possibilities. Although scientists have made some progress in the field of deep-red / near-infrared organic electroluminescent devices in recent years, their luminous efficiency is still insufficient compared to visible light OLEDs. Therefore, achieving highly efficient deep-red / near-infrared fluorescent devices remains a significant challenge. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide organic light-emitting materials, organic electroluminescent devices, and their fabrication. The organic light-emitting materials and devices based on phenanthrene derivatives of the present invention utilize benzene ring fusion to ensure high oscillator strength in the excited state, facilitating radiative transitions. Furthermore, their rigid fused-ring structure and non-bonded electronic structure effectively suppress intramolecular vibrations, helping to suppress non-radiative transitions in the excited state and achieve high photoluminescence efficiency. Additionally, these molecules can form intermolecular charge-transfer aggregates, thereby reducing non-adiabatic electron coupling and achieving low non-radiative transition rates, further improving photoluminescence efficiency. They can also stabilize the excited-state energy, enabling further application in organic electroluminescent devices to achieve high electroluminescence efficiency.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] This invention provides an organic light-emitting material, wherein the structural formula of the organic light-emitting material is selected from one of formula (I) or formula (II).

[0008]

[0009] Among them, Y1 and Y2 are independently selected from hydrogen or cyano; X1 and X2 are independently selected from C, H or N; L1, L2, L3, L4, L5, L6, L7 and L8 are independently selected from hydrogen atom, deuterium atom, halogen, cyano or substituted or unsubstituted A group;

[0010] The A group is selected from one of the following: C1 to C36 chain alkyl, C1 to C36 chain alkenyl, C1 to C36 chain alkynyl, C3 to C36 cycloalkyl, C4 to C36 cycloalkenyl, C4 to C36 cycloalkynyl, C1 to C30 alkoxy, C1 to C30 thioalkoxy, carbonyl, carboxyl, nitro, amino, C6 to C30 arylamino, C3 to C30 heteroarylamino, C6 to C60 monocyclic aryl, C6 to C60 fused-ring aryl, C4 to C60 aryloxy, C2 to C60 monocyclic heteroaryl, or C2 to C60 fused-ring heteroaryl.

[0011] In one embodiment of the present invention, L1 to L8 are each independently selected from one of hydrogen atom, deuterium atom, fluorine atom, chlorine atom, or substituted or unsubstituted A group;

[0012] The A group is selected from one of the following: C1 to C10 chain alkyl, C1 to C10 chain alkenyl, C1 to C10 chain alkynyl, C3 to C10 cycloalkyl, C4 to C10 cycloalkenyl, C4 to C10 cycloalkynyl, C1 to C10 alkoxy, C1 to C10 thioalkoxy, carbonyl, amino, C6 to C10 arylamino, C3 to C30 heteroarylamino, C6 to C30 monocyclic aryl, C6 to C30 fused-ring aryl, C4 to C30 aryloxy, C2 to C30 monocyclic heteroaryl, and C2 to C30 fused-ring heteroaryl.

[0013] In one embodiment of the present invention, L1 to L8 are each independently selected from one of hydrogen atom, deuterium atom, fluorine atom, chlorine atom, substituted or unsubstituted C6 to C30 monocyclic aromatic ring or fused aromatic ring, substituted or unsubstituted C4 to C30 monocyclic heterocyclic ring or fused heterocyclic ring.

[0014] In one embodiment of the present invention, L1 to L8 are each independently selected from one of hydrogen atoms, deuterium atoms, substituted or unsubstituted C6 to C20 monocyclic aromatic rings or fused aromatic rings, substituted or unsubstituted C4 to C20 monocyclic heterocycles or fused heterocycles.

[0015] In one embodiment of the present invention, L1 to L8 are each independently selected from one of the following formulas (A-1) to (A-25);

[0016]

[0017] The dashed line indicates that the position is a connecting key in formula (I) or formula (II);

[0018] R1~R 18Each is independently selected from one of the following: hydrogen, deuterium, fluorine, substituted or unsubstituted C1-C10 alkyl, C3-C10 cycloalkyl, substituted or unsubstituted C1-C10 alkoxy, substituted or unsubstituted C6-C20 monocyclic aromatic or fused aromatic, substituted or unsubstituted C2-C20 monocyclic heterocyclic or fused heterocyclic, C6-C10 arylamino, and C3-C30 heteroarylamino.

[0019] In one embodiment of the present invention, L1 to L8 are each independently selected from one of the following formulas (B-1) to (B-34);

[0020]

[0021]

[0022] In one embodiment of the present invention, the organic light-emitting material is selected from one of the following formulas (1-1) to (1-328) (in specific embodiments, they are referred to by reference numerals);

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037] A second objective of this invention is to provide a method for preparing an organic light-emitting material, comprising the following steps:

[0038] (S1) The first compound, oxalyl bromide and aluminum bromide are mixed and reacted, and the precursor is obtained after post-treatment.

[0039] (S2) The precursor obtained in step (S1) is mixed with the second compound and reacted, and then post-processed to obtain the intermediate;

[0040] (S3) The intermediate obtained in step (S2) is mixed with the third compound and reacted, and then post-processed to obtain the organic light-emitting material;

[0041] Alternatively, the intermediate obtained in step (S2) can be mixed with the fourth compound and reacted, followed by post-processing to obtain the organic light-emitting material;

[0042] The reaction processes in steps (S1), (S2), and (S3) above are all carried out under nitrogen protection.

[0043] In one embodiment of the present invention, in step (S1), the structural formula of the first compound is selected from one of the following formulas:

[0044]

[0045] In one embodiment of the present invention, in step (S1), the molar ratio of the first compound to oxalyl bromide is 1:(1 to 1.2), for example, it can be 1:1, 1:1.1, 1:1.2, etc.; the molar ratio of the first compound to aluminum bromide is 1:(2 to 2.5), for example, it can be 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, etc.

[0046] In one embodiment of the present invention, in step (S1), the temperature during the reaction process is -80℃ to 40℃, for example, it can be -80℃, -60℃, -40℃, -20℃, 0℃, 20℃, 40℃, etc.; the time is 1 to 7 hours, for example, it can be 1 hour, 3 hours, 5 hours, 7 hours, etc.

[0047] In one embodiment of the present invention, the reaction of the first compound, oxaloyl bromide, and aluminum bromide needs to be carried out in a low-boiling-point solvent, which includes carbon disulfide.

[0048] In one embodiment of the present invention, in step (S2), the structural formula of the second compound is selected from one of the following formulas:

[0049]

[0050] In one embodiment of the present invention, in step (S2), the molar ratio of the precursor to the second compound is 1:(1 to 1.2), for example, it can be 1:1, 1:1.1, 1:1.2, etc.

[0051] In one embodiment of the present invention, in step (S2), the temperature during the reaction process is 70°C to 110°C, for example, 70°C, 80°C, 90°C, 100°C, 110°C, etc.; the time is 8 to 12 hours, for example, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, etc.

[0052] In one embodiment of the present invention, in step (S2), the reaction of the precursor with the second compound needs to be carried out in an acidic solvent, which includes acetic acid.

[0053] In one embodiment of the present invention, in step (S3), the third compound is an aromatic amine, and the molar ratio of the intermediate to the third compound is 1:(1 to 1.3), for example, it can be 1:1, 1:1.1, 1:1.2, etc.

[0054] In one embodiment of the present invention, in step (S3), during the reaction between the intermediate and the third compound, the temperature is 90-150°C, for example, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, etc.; and the time is 12-24h, for example, 12h, 14h, 16h, 18h, 20h, 22h, 24h, etc.

[0055] In one embodiment of the invention, the reaction of the intermediate with the third compound needs to be carried out in a base, which includes cesium carbonate.

[0056] In one embodiment of the invention, the reaction of the intermediate with the third compound is carried out in a catalyst, the catalyst comprising palladium acetate and tri-tert-butylphosphine;

[0057] The molar ratio of palladium acetate to tri-tert-butylphosphine is 1:(1-3), for example, it can be 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8, 1:2, 1:2.2, 1:2.4, 1:2.6, 1:2.8, 1:3, etc.

[0058] In one embodiment of the present invention, the reaction of the intermediate with the third compound is carried out in a benzene-based solvent, including o-xylene.

[0059] Alternatively, in step (S3), the fourth compound is a boric acid derivative of an aromatic amine, and the molar ratio of the intermediate to the boric acid derivative of the aromatic amine is 1:(1 to 1.3), for example, it can be 1:1, 1:1.1, 1:1.2, etc.

[0060] In one embodiment of the present invention, in step (S3), during the reaction between the intermediate and the fourth compound, the temperature is 90-150°C, for example, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, etc.; and the time is 12-24h, for example, 12h, 14h, 16h, 18h, 20h, 22h, 24h, etc.

[0061] In one embodiment of the invention, the reaction of the intermediate with the fourth compound needs to be carried out in a base, which includes potassium carbonate.

[0062] In one embodiment of the invention, the reaction of the intermediate with the fourth compound is carried out in a catalyst, the catalyst comprising tetra(triphenylphosphine)palladium.

[0063] In one embodiment of the present invention, the reaction of the intermediate with the fourth compound needs to be carried out in a benzene-based solvent, which includes toluene;

[0064] Preferably, the benzene-based solvent is a mixture of toluene, water, and ethanol.

[0065] The third objective of this invention is to provide an application of organic light-emitting materials in the fabrication of organic electroluminescent devices.

[0066] A fourth object of the present invention is to provide an organic electroluminescent device, the organic electroluminescent device comprising an anode, a cathode, and an organic thin film layer located between the anode and the cathode;

[0067] The organic thin film layer includes a light-emitting layer made of the aforementioned organic light-emitting material.

[0068] In one embodiment of the present invention, the organic thin film layer includes a hole transport region, a light-emitting layer, and an electron transport region;

[0069] The anode is provided with a hole transport region, a light-emitting layer, and an electron transport region in sequence on the side closest to the cathode.

[0070] In one embodiment of the present invention, a substrate may be disposed below the anode or above the cathode, wherein the substrate is a glass or polymer material with excellent mechanical strength, thermal stability, water resistance and transparency; in addition, a thin-film transistor (TFT) may also be disposed on the substrate used for display.

[0071] The anode is obtained by sputtering or depositing anode material on a substrate; the anode material is selected from one or more of the following oxide transparent conductive materials: indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO);

[0072] The cathode can be obtained by sputtering or deposition as a cathode material; the cathode material is selected from one or more of magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), and magnesium-silver (Mg-Ag);

[0073] Organic thin film layers (hole transport region, light-emitting layer, electron transport region) are formed on electrodes (anode or cathode) by methods such as vacuum thermal evaporation, spin coating, and inkjet printing; the compounds used as organic thin film layers can be small organic molecules, large organic molecules, polymers, and combinations thereof;

[0074] Furthermore, the hole transport region is located between the anode and the light-emitting layer; the hole transport region can be a single-layer hole transport layer (HTL), including a single-layer hole transport layer containing only one compound and a single-layer hole transport layer containing multiple compounds; the hole transport region can also be a multi-layer structure including at least two layers of a hole injection layer (HIL), a hole transport layer (HTL), and an electron-blocking layer (EBL).

[0075] The materials of the hole transport region include, but are not limited to, phthalocyanine derivatives such as CuPc, conductive polymers or polymers containing conductive dopants such as polyphenylene ethylene, polyaniline / dodecylbenzenesulfonic acid (Pani / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (Pani / CSA), polyaniline / poly(4-styrenesulfonate) (Pani / PSS), and aromatic amine derivatives, one or more of these.

[0076] The electron transport region is selected from one or more of the following: electron injection layer (EIL), electron transport layer (ETL), and hole-blocking layer (HBL); the material of the electron transport layer includes, but is not limited to, benzimidazole derivatives such as 1,3,5-tris(1-phenyl-1H-benzimidazole-2-yl)benzene (TPBi), phenanthroline derivatives such as 4,7-diphenyl-1,10-phenanthroline (Bphen), and triazole derivatives such as 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole (TAZ); the material of the electron injection layer is selected from one or more of Liq, LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li, or Ca.

[0077] The sixth objective of this invention is to provide a method for fabricating an organic electroluminescent device, specifically comprising the following steps:

[0078] An anode is coated on the surface of a substrate, and then a hole transport layer, a light-emitting layer, an electron transport layer, and a cathode are sequentially deposited on the upper surface of the anode to obtain an organic electroluminescent device.

[0079] In one embodiment of the present invention, the thickness of the hole injection layer is 5-10 nm;

[0080] The thickness of the hole transport layer is 40–80 nm;

[0081] The thickness of the electron blocking layer is 5–10 nm;

[0082] The thickness of the light-emitting layer is 20–40 nm;

[0083] The thickness of the electron transport layer is 30–60 nm;

[0084] The thickness of the electron injection layer is 1 nm to 5 nm;

[0085] The thickness of the cathode is 100–150 nm.

[0086] Compared with the prior art, the present invention has the following beneficial effects:

[0087] (1) This invention proposes an acceptor based on a phenanthrene core. This acceptor, through benzene ring fusion, can ensure that the excited state has a high oscillator strength, which is conducive to radiative transitions. On the other hand, it can ensure the rigidity of the molecular structure and enhance the non-bonded electronic structure characteristics of the molecule, effectively reducing the vibration and rotation of the molecule to achieve a low non-radiative transition rate, ultimately achieving high luminescence efficiency. This acceptor has a strong electron-withdrawing effect, and the DA-type molecules obtained by combining with common donor units can obtain highly efficient deep red / near-infrared luminescence.

[0088] (2) The molecule of the present invention is a strong donor-acceptor type molecule. Its strong donor-acceptor structure helps to form intermolecular charge transfer aggregates in the solid state, thereby reducing the non-adiabatic coupling of electrons and reducing the nonradiative transition rate of the excited state to obtain efficient near-infrared photoluminescence. It can also stabilize the excited state energy, induce the generation of thermally activated delayed fluorescence, and realize efficient deep red / near-infrared electroluminescence. Attached Figure Description

[0089] Figure 1 The absorption and emission spectra of compounds 1-29 shown in Example 4 are as follows;

[0090] Figure 2 This is a schematic diagram of the structure of the organic light-emitting diode (OLED) in this invention;

[0091] The diagram is labeled as follows: 1. Anode; 2. Hole injection layer; 3. Hole transport layer; 4. Electron blocking layer; 5. Light emitting layer; 6. Electron transport layer; 7. Electron injection layer; 8. Cathode; 9. Substrate.

[0092] Figure 3 The image shows the electroluminescence spectrum of the OLED4 doped in TPBi as shown in Example 4. Detailed Implementation

[0093] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0094] In the following examples, unless otherwise specified, all reagents used are commercially available reagents, and all detection methods and techniques used are conventional detection methods and techniques in the field.

[0095] Example 1

[0096] This embodiment provides intermediate 1 and its preparation method (as shown in the following formula).

[0097]

[0098] (S1) Preparation of precursor b-1: 2-Bromophenanthrene (56.1 mmol), oxaloyl bromide (56.5 mmol), aluminum bromide (115 mmol), and carbon disulfide (300 mL) were added to a two-necked flask and stirred at -40 °C for 3 h under N2 protection, then heated to room temperature; after stirring for 1 h, the mixture was carefully poured into water; then it was completely extracted with dichloromethane, and the organic solution was eluted with dichloromethane by silica gel column chromatography to give 7.33 g of bright yellow solid, with a yield of 42%.

[0099] MS(EI): m / z = 309.96 [M] + Elemental analysis calculated value C 16 H7BrO2 (%): C, 61.77; H, 2.27; Br, 25.68; O, 10.28; Measured values: C, 61.85; H, 2.24; Br, 25.63; O, 10.28.

[0100] (S2) Preparation of Intermediate 1: The precursor b-1 (30 mmol) obtained in step (S1), 2,3-diamino-2-butenedionitrile (30 mmol) and acetic acid (150 mL) were added to a two-necked flask. Under N2 protection, the mixture was heated to reflux at 120 °C for 12 h. After the reaction was stopped, the mixture was cooled to room temperature, poured into water, filtered under reduced pressure, and washed with a large amount of water. The filter cake was then washed with anhydrous ethanol, and the filter cake was collected to obtain 10.35 g of orange-yellow solid, with a yield of 90%. MS (EI): m / z = 381.99 [M + Elemental analysis calculated value C20 H7BrN4 (%): C, 62.69; H, 1.84; Br, 20.85; N, 14.62; Measured values: C, 62.71; H, 1.79; Br, 20.94; N, 14.52.

[0101] Examples 2-18 Intermediate 2-Intermediate 18

[0102] Intermediates 2 to 18 were synthesized by cyclization of quinone and diamine according to the method shown in Example 1, the difference being the different starting materials used; the structures, yields and mass spectrometry data of the starting materials and intermediate compounds are shown in Table 1.

[0103] Table 1. Structure, yield, and mass spectrometry data of the raw materials and intermediate compounds used in Examples 1-18

[0104]

[0105]

[0106] Example 19 Synthesis of Compounds 1-2

[0107]

[0108] Intermediate 2 (6 mmol) prepared in Example 2, diphenylamine (6.6 mmol), palladium acetate (0.3 mmol), tri-tert-butylphosphine (0.9 mmol), cesium carbonate (12 mmol), and o-xylene (30 mL) were added to a two-necked flask and heated under N2 protection at 120 °C for 24 h under reflux. After the reaction was stopped, the mixture was cooled to room temperature, and dioxane was removed by rotary evaporation. The dioxane was purified by separation on a silica gel column using petroleum ether:dichloromethane = 2:1 as eluent. 2.38 g of a red solid was given, with a yield of 84%. MS (EI): m / z = 471.15 [M] + Elemental analysis calculated value C 32 H 17 N5 (%): C, 81.51; H, 3.63; N, 14.85; Measured values: C, 81.52; H, 3.62; N, 14.86.

[0109] All compounds involving aromatic amines in this invention, in which nitrogen atoms are directly linked to the bromine substitution sites of intermediates 1 to 18 via carbon-nitrogen bonds, are synthesized according to this method.

[0110] Example 20, Synthesis of Compounds 1-29

[0111]

[0112] Intermediate 2 (7 mmol) prepared in Example 2, triphenylamine 4-borate (7.5 mmol), tetrakis(triphenylphosphine)palladium (0.3 mmol), potassium carbonate (9 mmol), and a mixture of toluene, water, and ethanol (total 30 mL) were added to a two-necked flask and heated under N2 protection at 100 °C for 12 h under reflux. After the reaction was stopped, the mixture was cooled to room temperature, poured into a separatory funnel, and extracted with an appropriate amount of water and dichloromethane. The organic phase was collected. The mixture was purified by separation on a silica gel column using petroleum ether:dichloromethane = 2:1 as the eluent. 2.36 g of a purple solid was obtained, with a yield of 71%. MS (EI): m / z = 381.99 [M] + Elemental analysis calculated value C 38 H 21 N5 (%): C, 83.35; H, 3.87; N, 12.79; Measured values: C, 83.45; H, 3.76; N, 12.78.

[0113] according to Figure 1 As shown, the peak value of the absorption spectrum of the compound represented by Formula 1-29 is approximately 480 nm, and the peak value of the emission spectrum is approximately 760 nm.

[0114] All compounds involving aromatic amines in this invention, which are linked by carbon-carbon bonds to the bromine substitution sites of intermediates 1 to 18 via benzene or other aromatic rings, are synthesized according to this method.

[0115] Example 21

[0116] This embodiment provides an organic electroluminescent device and its fabrication method.

[0117] like Figure 2 As shown, the organic electroluminescent device includes an anode 1, a hole injection layer 2, a hole transport layer 3, an electron blocking layer 4, a light-emitting layer 5, an electron transport layer 6, an electron injection layer 7, and a cathode 8 disposed on the upper surface of a substrate 9.

[0118] Its preparation process is as follows:

[0119] (S1) The glass plate coated with ITO (as anode) transparent conductive layer was ultrasonically treated in commercial cleaning agent, rinsed in deionized water, cleaned three times each in acetone and ethanol, baked in a clean environment until the moisture was completely removed, cleaned with ultraviolet light and ozone, and bombarded with low-energy cation beam.

[0120] (S2) After step (S1) is completed, place it in a vacuum chamber and evacuate it to 1×10⁻⁶. -5 ~9×10 -3 Pa, a 10 nm thick HATCN layer is vacuum-deposited on the upper surface of the anode at a deposition rate of 0.1 nm / s as a hole injection layer.

[0121] (S3) A 70 nm thick NPB layer is vacuum-deposited on top of the hole injection layer at a deposition rate of 0.1 nm / s as a hole transport layer.

[0122] (S4) A 10 nm thick TCTA layer is vacuum-deposited on the hole transport layer at a deposition rate of 0.1 nm / s as an electron blocking layer.

[0123] (S5) 10 wt% compound 1-1 and 90 wt% TPBi were vacuum deposited on the electron blocking layer at a deposition rate of 0.1 nm / s to a thickness of 30 nm as a light-emitting layer (compound 1-1 is the dye material and TPBi is the host material; deposition rate is 0.1 nm / s).

[0124] (S6) A TPBi layer with a thickness of 60 nm is vacuum-deposited on the light-emitting layer at a deposition rate of 0.1 nm / s as an electron transport layer.

[0125] (S7) A 1 nm thick LiF layer is vacuum-deposited on top of the electron transport layer at a deposition rate of 0.1 nm / s as an electron injection layer.

[0126] (S8) An Al layer with a thickness of 150 nm is vacuum-deposited on the electron injection layer at a deposition rate of 0.1 nm / s as the cathode of the device.

[0127] Examples 22 to 51 and Comparative Example 1

[0128] Compared with Example 21, everything is the same except that the dye material in the light-emitting layer is replaced. The specific selection of dye materials in each example and comparative example is shown in Table 2.

[0129] The absolute external quantum efficiency measurement system C9920-12 from Hamamatsu Corporation, Japan, along with a Hamamatsu C10027-02 PMA-12 photonic multichannel spectrometer (detection range 350-1100 nm) and a Keithley 2400 multifunction power meter, were used to measure parameters such as device voltage, external quantum efficiency, current density, and brightness. All measurements were performed at room temperature under atmospheric conditions; the results are shown in Table 2.

[0130] The electroluminescence spectrum of the OLED4 doped in TPBi prepared in Example 24 is shown below. Figure 3 As shown.

[0131] Table 2 Summary of Organic Electroluminescent Devices and Their Performance in Examples 21-51 and Comparative Example 1 Table of Organic Electroluminescent Devices and Their Performance

[0132]

[0133]

[0134] The performance comparison results of the devices prepared according to the present invention above show that the organic electroluminescent devices prepared using the preferred compounds of the present invention have advantages such as high luminous efficiency. On the one hand, the phenanthrene core, through benzene ring fusion, can ensure that the excited state has a high oscillator strength, which is beneficial to radiative transitions; on the other hand, it can ensure the rigidity of the molecular structure, and by introducing non-bonded electronic structures to a certain extent, it can effectively reduce molecular vibration and rotation, suppress non-radiative transitions, and achieve a low non-radiative transition rate. In addition, the molecule designed in this invention is a strong donor-acceptor type molecule, whose strong donor-acceptor structure helps to form intermolecular charge transfer aggregates in the solid state, thereby reducing the overlap of electrons and holes in the excited state, effectively suppressing non-adiabatic electron coupling, and stabilizing the excited state energy, thereby improving luminous efficiency. Therefore, when suitable electron-donating and electron-withdrawing units are introduced on the phenanthrene core, efficient long-wavelength emission can be easily obtained, meeting its application requirements in the field of deep red / near-infrared organic electroluminescent devices.

[0135] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the interpretation of the present invention, without departing from the scope of the invention, should be within the protection scope of the present invention.

Claims

1. An organic light-emitting material, characterized in that, The structural formula of the organic light-emitting material is selected from either formula (I) or formula (II). (I), (II); Wherein, Y1 and Y2 are independently selected from hydrogen or cyano; X1 and X2 are independently selected from C, H or N; L1 to L8 are each independently selected from one of the following: hydrogen atom, deuterium atom, fluorine atom, chlorine atom, or substituted or unsubstituted A group; The A group is selected from one of the following: C1 to C10 chain alkyl, C1 to C10 chain alkenyl, C1 to C10 chain alkynyl, C3 to C10 cycloalkyl, C4 to C10 cycloalkenyl, C4 to C10 cycloalkynyl, C1 to C10 alkoxy, C1 to C10 thioalkoxy, carbonyl, amino, C6 to C10 arylamino, C3 to C30 heteroarylamino, C6 to C30 monocyclic aryl, C6 to C30 fused-ring aryl, C4 to C30 aryloxy, C2 to C30 monocyclic heteroaryl, and C2 to C30 fused-ring heteroaryl.

2. The organic light-emitting material according to claim 1, characterized in that, The organic light-emitting material is selected from one of the following formulas (1-1) to (218) and (220) to (1-328); 。 3. A method for preparing the organic light-emitting material as described in any one of claims 1 to 2, characterized in that, Includes the following steps: (S1) The first compound, oxalyl bromide and aluminum bromide were mixed and reacted, and the precursor was obtained after post-treatment; The structural formula of the first compound is selected from one of the following formulas: 、 、 、 ； (S2) The precursor obtained in step (S1) is mixed with the second compound and reacted, and then post-processed to obtain the intermediate; The structural formula of the second compound is selected from one of the following formulas: 、 、 、 、 、 ； (S3) The intermediate obtained in step (S2) is mixed with the third compound and reacted, and then post-processed to obtain the organic light-emitting material; The third compound is an aromatic amine; Alternatively, the intermediate obtained in step (S2) can be mixed with the fourth compound and reacted, followed by post-processing to obtain the organic light-emitting material; The fourth compound is a boric acid derivative of an aromatic amine; The reaction processes in steps (S1), (S2), and (S3) above are all carried out under nitrogen protection.

4. The method for preparing an organic light-emitting material according to claim 3, characterized in that, In step (S1), the molar ratio of the first compound and aluminum oxaloyl bromide is 1:(1~1.2):(2~2.5). During the reaction, the temperature ranges from -80℃ to 40℃, and the time ranges from 1 to 7 hours.

5. The method for preparing an organic light-emitting material according to claim 3, characterized in that, In step (S2), the molar ratio of the precursor to the second compound is 1:(1~1.2); During the reaction, the temperature is 70℃~110℃ and the time is 8~12h.

6. The method for preparing an organic light-emitting material according to claim 3, characterized in that, In step (S3), the molar ratio of the intermediate to the third compound is 1:(1~1.3); during the reaction, the temperature is 90~150℃ and the time is 12~24h. Alternatively, in step (S3), the molar ratio of the intermediate to the boric acid derivative of the aromatic amine is 1:(1~1.3); during the reaction, the temperature is 90~150℃ and the time is 12~24h.

7. The application of an organic light-emitting material as described in any one of claims 1 to 2 in the preparation of organic electroluminescent devices.

8. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes an anode, a cathode, and an organic thin film layer located between the anode and the cathode; The organic thin film layer includes a hole transport region, a light-emitting layer, and an electron transport region; The anode is provided with a hole transport region, a light-emitting layer, and an electron transport region in sequence on the side closest to the cathode. The light-emitting layer is made of the organic light-emitting material described in any one of claims 1 to 2.

9. A method for fabricating an organic electroluminescent device as described in claim 8, characterized in that, Specifically, the following steps are included: An anode is coated on the surface of a substrate, and then a hole transport region, a light-emitting layer, an electron transport region, and a cathode are sequentially deposited on the upper surface of the anode to obtain an organic electroluminescent device.

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