Organic electroluminescent compound, organic electroluminescent device and intermediate for synthesizing organic electroluminescent compound

Abstract

The invention relates to the field of organic electroluminescence, and particularly discloses an organic electroluminescence compound, an organic electroluminescence device and an intermediate for synthesizing the organic electroluminescence compound. The structure of the organic electroluminescent compound is shown as a formula (I), wherein X and Y are independently selected from C1-C20 alkyl groups and C1-C20 alkoxy groups; ar1, Ar2, Ar3 and Ar4 are respectively and independently selected from C6-C60 aryl groups; a and B are independently selected from C6-C60 aryl groups, and m and n are independently selected from 0 and 1; the compound shown in the formula (I) can be substituted by C1-C20 alkyl groups, alkoxy groups and C6-C60 aryl groups. The organic electroluminescent device comprises a cathode layer, an anode layer and an organic layer located between the cathode layer and the anode layer, wherein the organic layer contains an organic electroluminescent compound. The organic light-emitting device can improve the light-emitting efficiency, prolong the service life, and reduce the driving voltage and the efficiency roll-off. .

Description

[0001] This application is a divisional application of patent application number 202210273159.5 (the original application was filed on March 18, 2022, and the invention was entitled "An Organic Electroluminescent Compound, An Organic Electroluminescent Device and an Intermediate for Synthesizing an Organic Electroluminescent Compound"). Technical Field

[0002] This application relates to the field of organic electroluminescence, and more specifically, to an organic electroluminescent compound, an organic electroluminescent device, and an intermediate for synthesizing the organic electroluminescent compound. Background Technology

[0003] Organic light-emitting devices (OLEDs) refer to the phenomenon where organic semiconductor materials and light-emitting materials emit light through carrier injection and recombination under the drive of an electric field. The principle involves using an ITO transparent electrode and metal electrodes as the anode and cathode of the OLED, respectively. Under a certain voltage, electrons and holes are injected from the cathode and anode into the electron transport layer and hole transport layer, respectively. The electrons and holes then migrate through the electron transport layer and hole transport layer to the light-emitting layer, where they meet, forming excitons and exciting the light-emitting molecules. These molecules then emit visible light through radiative relaxation.

[0004] Organic light-emitting diodes (OLEDs) possess advantages such as wide viewing angle, low power consumption, fast response speed, high luminous brightness and efficiency, and the ability to achieve full-color displays, making them highly valued by the scientific and industrial communities. Currently, although significant progress has been made in OLED research, developing new materials to further improve their performance (e.g., increasing luminous efficiency and lifespan, and reducing driving voltage) remains a focus of research efforts.

[0005] Furthermore, some OLED devices, such as near-eye display OLED devices and OLED displays used in VR and AR glasses, require high brightness to operate. Conventional OLED devices experience a significant decrease in current efficiency as brightness increases, a phenomenon known as efficiency roll-off. Therefore, it is necessary to develop materials with low efficiency roll-off. Summary of the Invention

[0006] In order to improve the luminous efficiency of organic electroluminescent devices, reduce the driving voltage of organic electroluminescent devices, extend the service life of organic electroluminescent devices, and significantly reduce the efficiency roll-off of organic electroluminescent devices, this application provides an organic electroluminescent compound and an organic electroluminescent device.

[0007] Firstly, this application provides an organic electroluminescent compound, which adopts the following technical solution: The structure of an organic electroluminescent compound is shown in formula (I):

[0008] In formula (I), X and Y are each independently selected from C1-C20 alkyl and C1-C20 alkoxy groups; Ar1, Ar2, Ar3, and Ar4 are each independently selected from C6 to C60 aryl groups, and at least one substituent in Ar1, Ar2, Ar3, and Ar4 is selected from C12 to C24 aryl groups; A and B are each independently selected from C6 to C60 aryl groups, and m and n are each independently selected from 0 and 1.

[0009] Optionally, X and Y are each independently selected from C1 to C20 primary alkyl groups (e.g.: ), C3 to C20 secondary alkyl groups (e.g.: ), C4 to C20 tertiary alkyl groups (e.g.: ), C1~C20 primary alkoxy groups (e.g.: ), C3~C20 secondary alkoxy groups (e.g.: ), C4-C20 tertiary alkoxy groups (e.g.: Preferably, X and Y are each independently selected from C3-C20 secondary alkyl, C4-C20 tertiary alkyl, C3-C20 secondary alkoxy, and C4-C20 tertiary alkoxy. More preferably, X and Y are each independently selected from C4-C20 tertiary alkyl and C4-C20 tertiary alkoxy.

[0010] Optionally, Ar1, Ar2, Ar3, and Ar4 are each independently selected from benzene, biphenyl, naphthalene, triphenylene, fluoranthene, 9,9-dimethylfluorene, 9,9-diphenylfluorene, dibenzofuran, dibenzothiophene, carbazole, indolo[2,3-a]carbazole, indolo[3,2-b]carbazole, 1,2-benzofluorene, 2,3-benzofluorene, spirofluorene, indocarbazole, dibenzofluorene, naphthofluorene, benzodibenzofuran, and benzodibenzothiophene.

[0011] Optionally, Ar1, Ar2, Ar3, and Ar4 are each independently selected from one of the following monovalent organic groups:

[0012]

[0013]

[0014]

[0015]

[0016] .

[0017] Optionally, Ar1, Ar2, Ar3, and Ar4 are each independently selected from C12 to C24 aryl groups. Preferably, at least two substituents in Ar1, Ar2, Ar3, and Ar4 are each independently selected from C12 to C24 aryl groups. More preferably, at least three substituents in Ar1, Ar2, Ar3, and Ar4 are each independently selected from C12 to C24 aryl groups. Even more preferably, Ar1, Ar2, Ar3, and Ar4 are each independently selected from C12 to C24 aryl groups.

[0018] Optionally, A and B can be independently selected from benzene, biphenyl, 9,9-dimethylfluorene, naphthalene, triphenylene, and fluoranthene.

[0019] Optionally, A and B may each be independently selected from one of the following divalent organic groups:

[0020]

[0021]

[0022]

[0023] Optionally, m=1 and n=1, m=1 and n=0, m=0 and n=1, m=0 and n=0. Preferably, m=1 and n=0, m=0 and n=1, m=0 and n=0. Most preferably, m=0 and n=0.

[0024] Optionally, the organic electroluminescent compound is one of the following compounds:

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036] Secondly, the organic electroluminescent device provided in this application adopts the following technical solution: An organic electroluminescent device includes a cathode layer, an anode layer, and an organic layer located in the cathode layer and the anode layer, wherein the organic layer contains one of the aforementioned organic electroluminescent compounds.

[0037] Optionally, the organic layer includes a light-emitting layer and a hole transport layer located between the light-emitting layer and the anode layer; The hole transport layer contains one of the aforementioned organic electroluminescent compounds. And / or, the light-emitting layer contains one of the aforementioned organic electroluminescent compounds.

[0038] Optionally, the organic layer includes a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer arranged sequentially from the anode layer to the cathode layer. Alternatively, the organic layer includes a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer arranged sequentially from the anode layer to the cathode layer.

[0039] Thirdly, this application provides an intermediate for synthesizing organic electroluminescent compounds, employing the following technical solution: An intermediate for synthesizing an organic electroluminescent compound is one of the following brominated derivatives:

[0040]

[0041]

[0042]

[0043] .

[0044] In summary, this application has the following beneficial effects: by using the organic electroluminescent compound of this application as the hole transport material or red light host material of the organic electroluminescent device, the prepared organic electroluminescent device can improve luminous efficiency, reduce driving voltage, extend service life, and significantly reduce efficiency roll-off. Detailed Implementation

[0045] The present application will be further described in detail below with reference to the embodiments.

[0046] Examples of the synthesis of organic electroluminescent compounds Synthesis Example 1

[0047] The method for synthesizing the organic electroluminescent compound I-1 includes the following steps:

[0048] Synthesis of organic electroluminescent compound I-1: Under nitrogen protection, 1,4-dioxane (300 mL), water (100 mL), the brominated compound shown in M-1-1 (5.86 g, 0.01 mol), the borate compound shown in M-1-2 (8.03 g, 0.022 mol), sodium carbonate (5.3 g, 0.05 mol), and tetraphenylphosphine palladium (0.23 g, 0.0002 mol) were added to a 500 mL three-necked flask. The mixture was slowly heated to reflux and refluxed for 8 hours. After the reaction was completed, the mixture was cooled, water and toluene were added, and the layers were separated. The organic layer was washed with water, dried over magnesium sulfate, filtered to remove magnesium sulfate, and the solvent was removed under reduced pressure. The obtained solid silica gel was separated by column chromatography, eluted with petroleum ether, to obtain organic electroluminescent compound I-1 (8.1 g).

[0049] The organic electroluminescent compound I-1 was analyzed by mass spectrometry, and the molecular m / z was determined to be 1066.52.

[0050] NMR analysis was performed on the organic electroluminescent compound I-1, and the data analysis is as follows: 1¹H-NMR (Bruker, Switzerland, Avance II 400MHz NMR spectrometer, CDCl3) δppm: 8.06 (d, 2H), 7.83–7.72 (m, 10H), 7.59–7.46 (m, 12H), 7.45–7.34 (m, 12H), 7.28–7.20 (m, 6H), 7.09 (m, 4H), 6.99 (m, 2H), 1.27 (s, 18H).

[0051] Synthesis Example 2

[0052] The method for synthesizing the organic electroluminescent compound I-8 includes the following steps:

[0053] Synthesis of organic electroluminescent compound I-8: Following the synthesis steps of organic electroluminescent compound I-1 in Synthesis Example 1, except that the boric acid compound shown in M-1-2 is replaced with the boric acid compound shown in M-8-2, organic electroluminescent compound I-8 is obtained.

[0054] Mass spectrometry was used to detect the organic electroluminescent compound I-8, and the molecular m / z was determined to be 1246.54.

[0055] Synthesis Example 3

[0056] The method for synthesizing the organic electroluminescent compound I-22 includes the following steps:

[0057] Synthesis of organic electroluminescent compound I-22: Following the synthesis steps of organic electroluminescent compound I-1 in Synthesis Example 1, only the types of corresponding brominated compounds and boric acid compounds were changed, and the amount of brominated compounds was 2.2 times that of boric acid compounds, to obtain organic electroluminescent compound I-22.

[0058] Mass spectrometry was used to detect the organic electroluminescent compound I-22, and the molecular m / z was determined to be 1244.58.

[0059] Synthesis Example 4

[0060] The method for synthesizing the organic electroluminescent compound I-28 includes the following steps:

[0061] Synthesis of the intermediate shown in I-28-1: Under nitrogen protection, 1,4-dioxane (200 mL), water (80 mL), the brominated compound shown in M-1-1 (5.86 g, 0.01 mol), the borate compound shown in M-28-0 (2.89 g, 0.01 mol), sodium carbonate (2.06 g, 0.02 mol), and tetraphenylphosphine palladium (0.115 g, 0.0001 mol) were added to a 500 mL three-necked flask. The mixture was slowly heated to reflux and refluxed for 8 hours. After the reaction was completed, the mixture was cooled, and water and toluene were added to separate the layers to obtain an organic layer. The organic layer was washed with water, dried over magnesium sulfate, filtered to remove magnesium sulfate, and the solvent was removed under reduced pressure. The obtained solid was separated by silica gel column chromatography and eluted with petroleum ether to obtain the intermediate shown in I-28-1 (5.1 g).

[0062] Mass spectrometry analysis was performed on the intermediate shown in I-28-1. The two largest m / z peaks were 749.27 and 751.26, confirming the product's molecular formula as C. 51 H 44 BrN.

[0063]

[0064] Synthesis of the organic electroluminescent compound I-28: Under nitrogen protection, 1,4-dioxane (300 mL), water (100 mL), intermediate shown in I-28-1 (7.51 g, 0.01 mol), borate compound shown in M-28-2 (4.41 g, 0.01 mol), sodium carbonate (2.06 g, 0.02 mol), and tetraphenylphosphine palladium (0.115 g, 0.0001 mol) were added to a 500 mL three-necked flask. The mixture was slowly heated to reflux and refluxed for 8 hours. After the reaction was completed, the mixture was cooled, water and toluene were added, and the layers were separated. The organic layer was washed with water, dried over magnesium sulfate, filtered to remove magnesium sulfate, and the solvent was removed under reduced pressure. The obtained solid silica gel was separated by column chromatography, eluted with petroleum ether, to obtain the organic electroluminescent compound I-28 (8.6 g).

[0065] The organic electroluminescent compound I-28 was detected by mass spectrometry, m / z: 1066.52.

[0066] Synthesis Example 5

[0067] The method for synthesizing the organic electroluminescent compound I-54 includes the following steps:

[0068] Synthesis of intermediate 5-1: Nitrobenzene (300 mL), biphenyl (15.4 g, 0.1 mol), and anhydrous aluminum trichloride (40 g, 0.3 mol) were added to a 1000 mL three-necked flask. After stirring evenly, the mixture was cooled to 5 °C, and 1-chloro-1-methylcyclohexane (27.85 g, 0.21 mol) was slowly added dropwise. After the addition was complete, the mixture was kept at 5 °C for 1 hour, and then slowly heated to 25 °C for 2 hours. After the reaction was complete, the reaction solution was slowly poured into ice water, and the organic layer was separated. The organic layer was washed with water until neutral, and then activated carbon (5 g) was added to the organic layer and heated to 60 °C for 30 minutes. The activated carbon was filtered off, and the mother liquor was concentrated to dryness under reduced pressure. The mixture was crystallized twice with ethanol to obtain intermediate 5-1 (2.8 g).

[0069] The intermediate 5-1 was analyzed by mass spectrometry, m / z: 346.27.

[0070]

[0071] Synthesis of intermediate 5-2: Compound 5-1 (3.46 g, 0.01 mol), dichloromethane (20 mL), acetic anhydride (5 mL), and iodine (1 grain) were added to a 250 mL three-necked flask. The mixture was stirred and cooled to 0 °C. A solution of liquid bromine (1.6 g, 0.01 mol) in dichloromethane (5 mL) was slowly added dropwise. After the addition was complete, the mixture was kept at 0 °C for 6 hours. Water was added to obtain an organic layer. The organic layer was washed sequentially with water, then with sodium bisulfite solution, and then with water until neutral. The organic layer was dried over magnesium sulfate and concentrated to dryness under reduced pressure. The resulting solid was separated by silica gel column chromatography and eluted with petroleum ether to obtain intermediate 5-2 (2.8 g).

[0072] Mass spectrometry analysis was performed on intermediate 5-2, and the two largest m / z peaks were found at 424.18 and 426.17, confirming the product's molecular formula as C. 26 H 33 Br.

[0073] NMR analysis was performed on intermediate 5-2, and the data analysis is as follows: 1 H-NMR (Bruker, Switzerland, Avance II 400MHz NMR spectrometer, CDCl3) δppm: 7.68 (d, 1H), 7.59 (d, 1H), 7.49 (m, 2H), 7.39 (m, 2H), 7.33 (m, 1H), 1.98 (m, 4H), 1.76 (m, 4H), 1.59~1.39 (m, 12H), 1.33 (s, 6H).

[0074]

[0075] Synthesis of intermediate 5-3: Under nitrogen protection, dry tetrahydrofuran (200 mL) and compound 5-3 (5.1 g, 0.012 mol) were added to a 500 mL three-necked flask. The temperature was lowered to -78 °C, and a 1.6 M solution of butyllithium in n-hexane (6.56 mL, 0.0105 mol of butyllithium) was slowly added dropwise. After the addition was complete, the temperature was maintained at -78 °C for 30 minutes. Then, 9-fluorenone (1.8 g, 0.1 mol) was added, and the temperature was slowly raised to 25 °C and maintained for 2 hours. After the reaction was complete, the reaction solution was slowly poured into water, toluene was added, and the mixture was stirred and separated to obtain an organic layer. The organic layer was washed with water and concentrated to dryness. Then, acetic acid (100 mL) and 36% hydrochloric acid (5 mL) were added, and the mixture was heated under reflux for 4 hours, precipitating a yellow solid. The mixture was cooled, filtered, and the resulting yellow solid was sequentially washed with ethanol, washed with water, and dried to obtain intermediate 5-3 (3.8 g).

[0076] The intermediate 5-3 was analyzed by mass spectrometry, and the m / z was 508.31.

[0077]

[0078] Synthesis of intermediate M-54-1: Compound 5-2 (5.09 g, 0.01 mol), dichloromethane (50 mL), and iron powder (1.0 g) were added to a 250 mL three-necked flask. A solution of liquid bromine (3.2 g, 0.02 mol) in dichloromethane (10 mL) was slowly added dropwise at 20–30 °C. After the addition was complete, the reaction was carried out at 20–30 °C for 4 hours. After the reaction was complete, water was added to the reaction solution, and the mixture was filtered to obtain an organic layer. The organic layer was washed with water, then with sodium bisulfite solution, and finally with water until neutral. After drying the organic layer with magnesium sulfate, it was concentrated to dryness under reduced pressure. The obtained solid silica gel column chromatography was used for separation, and petroleum ether was used as elution to obtain intermediate M-54-1 (5.5 g).

[0079] Mass spectrometry analysis was performed on intermediate M-54-1. The strongest m / z peak was at 666.13 (100% intensity), with peaks at 664.13 and 668.13 (approximately 50% intensity). The molecular formula of intermediate M-54-1 was determined to be C1. 39 H 38 Br2.

[0080]

[0081] Synthesis of organic electroluminescent compound I-54: Following the synthesis steps of organic electroluminescent compound I-1 in Synthesis Example 1, only the types of corresponding brominated compounds and boric acid compounds were changed to obtain organic electroluminescent compound I-54.

[0082] Mass spectrometry was used to detect the organic electroluminescent compound I-54, and the molecular m / z was determined to be 1146.59.

[0083] Synthesis Example 6

[0084] The method for synthesizing the organic electroluminescent compound I-58 includes the following steps:

[0085] Synthesis of intermediate 8-2: Refer to the synthesis steps of intermediate 5-2 in Synthesis Example 5, except that intermediate 5-1 (3.46 g, 0.01 mol) is replaced with the compound shown in Formula 8-1 (2.98 g, 0.01 mol) to obtain intermediate 8-2 (1.6 g).

[0086] Mass spectrometry analysis was performed on intermediate 8-2, and the two largest m / z peaks were found at 376.10 and 378.10, confirming the molecular formula as C. 20 H 25 BrO2.

[0087] NMR analysis was performed on intermediate 8-2, and the data analysis is as follows: 1 H-NMR (Bruker, Switzerland, Avance II 400MHz NMR spectrometer, CDCl3) δppm: 7.70 (m, 2H), 7.65 (d, 1H), 7.48 (d, 1H), 7.02 (m, 2H), 6.99 (m, 1H), 1.37 (s, 18H).

[0088]

[0089] Synthesis of intermediate 8-3: Refer to the synthesis steps of intermediate 5-3 in synthesis example 5, except that the intermediate shown in 5-2 is replaced with the intermediate shown in 8-2 to obtain intermediate 8-3.

[0090] The intermediate 8-3 was analyzed by mass spectrometry, m / z: 460.24.

[0091]

[0092] Synthesis of intermediate M-58-1: Refer to the synthesis steps of intermediate M-54-1 in synthesis example 5, except that the intermediate shown in 5-3 is replaced with the intermediate shown in 8-3 to obtain intermediate M-58-1.

[0093] Mass spectrometry analysis was performed on intermediate M-58-1. The strongest m / z peak was at 618.06 (100% intensity), with other peaks at 616.06 and 620.06 (approximately 50% intensity). The molecular formula of intermediate M-58-1 was determined to be C1. 33 H 30 Br2O2.

[0094]

[0095] Synthesis of organic electroluminescent compound I-58: Following the synthesis steps of organic electroluminescent compound I-1 in Synthesis Example 1, only the types of corresponding brominated compounds and boric acid compounds were changed to obtain organic electroluminescent compound I-58.

[0096] Mass spectrometry was used to detect the organic electroluminescent compound I-58, and the molecular m / z was determined to be 1098.51.

[0097] Synthesis Example 7

[0098] The method for synthesizing the organic electroluminescent compound I-62 includes the following steps:

[0099] Synthesis of intermediate 6-1: Refer to the synthesis steps of intermediate 5-1 in Synthesis Example 5, except that 1-chloro-1-methylcyclohexane is replaced with 1-chloro-1-methylcyclopentane to obtain intermediate 6-1.

[0100] Intermediate 6-1 was analyzed by mass spectrometry, m / z: 318.23.

[0101]

[0102] Synthesis of intermediate 6-2: Refer to the synthesis steps of intermediate 5-2 in synthesis example 5, except that the intermediate shown in 5-1 is replaced with the intermediate shown in 6-1 to obtain intermediate 6-2.

[0103] Mass spectrometry analysis was performed on intermediate 6-2, and the two largest m / z peaks were found at 396.15 and 398.14, confirming the product's molecular formula as C. 24 H 29 Br.

[0104]

[0105] Synthesis of intermediate 6-3: Refer to the synthesis steps of intermediate 5-3 in synthesis example 5, except that the intermediate shown in 5-2 is replaced with the intermediate shown in 6-2 to obtain intermediate 6-3.

[0106] The intermediate 6-3 was analyzed by mass spectrometry, m / z: 480.28.

[0107]

[0108] Synthesis of intermediate M-62-1: Refer to the synthesis steps of intermediate M-54-1 in synthesis example 5, except that the intermediate shown in 5-3 is replaced with the intermediate shown in 6-3 to obtain intermediate M-62-1.

[0109] Mass spectrometry analysis was performed on intermediate M-62-1. The strongest m / z peak was at 638.10 (100% intensity), with other peaks at 636.10 and 640.10 (approximately 50% intensity). The molecular formula of intermediate M-62-1 was determined to be C1. 37 H 34 Br2.

[0110]

[0111] Organic electroluminescent compound I-62: Following the synthesis steps of the compound shown in Formula I-1 in Example 1, only the types of corresponding brominated derivatives and boric acid compounds were changed to obtain organic electroluminescent compound I-62.

[0112] Mass spectrometry was used to detect the organic electroluminescent compound I-62, and the molecular m / z was determined to be 1118.55. Synthesis Example 8

[0113] The method for synthesizing the organic electroluminescent compound II-3 includes the following steps:

[0114] Synthesis of intermediate II-3-1: Under nitrogen protection, dry toluene (100 mL), the brominated compound shown in M-1-1 (5.86 g, 0.01 mol), the compound shown in formula II-3-0 (3.21 g, 0.01 mol), Pd(dba)2 (bis(dibenzylacetone)palladium(0), 0.0575 g, 0.0001 mol), a toluene solution of tri-tert-butylphosphine (0.4 g, tri-tert-butylphosphine: 0.0002 mol) with a weight percentage of 10%, and sodium tert-butoxide (1.44 g, 0.015 mol) were added to a 250 mL three-necked flask. The mixture was heated to reflux for 6 hours, cooled, and water was added to obtain an organic layer. The organic layer was washed with water until neutral, dried over magnesium sulfate, filtered to remove magnesium sulfate, concentrated to dryness, separated by silica gel column chromatography, and eluted with petroleum ether to obtain intermediate II-3-1 (5.8 g).

[0115] Mass spectrometry analysis of intermediate II-3-1 revealed two peaks with the largest m / z values ​​at 825.30 and 827.29, confirming the product's molecular formula as C. 57 H 48 BrN.

[0116]

[0117] Synthesis of organic electroluminescent compound II-3: Following the synthesis steps of organic electroluminescent compound I-28 in Synthesis Example 4, only the types of corresponding brominated compounds and boric acid compounds were changed to obtain organic electroluminescent compound II-3.

[0118] Mass spectrometry was used to detect the organic electroluminescent compound II-3, and the molecular m / z was determined to be 1142.55.

[0119] Synthesis Example 9

[0120] The method for synthesizing the organic electroluminescent compound II-54 includes the following steps:

[0121] Synthesis of intermediate II-54-1: Refer to the synthesis steps of intermediate II-3-1 in Synthesis Example 8, except that the compound shown in M-1-1 is replaced with the compound shown in M-54-1, and the compound shown in II-3-0 is replaced with the compound shown in II-54-0, to obtain intermediate II-54-1.

[0122] Mass spectrometry analysis was performed on intermediate II-54-1. The two largest m / z peaks were found at 829.33 and 831.33, confirming the product's molecular formula as C. 57 H 52 BrN.

[0123]

[0124] Synthesis of organic electroluminescent compound II-54: Following the synthetic steps of organic electroluminescent compound I-28 in Synthesis Example 4, but changing the types of corresponding brominated compounds and borate compounds, organic electroluminescent compound II-54 was obtained.

[0125] The organic electroluminescent compound II-54 was analyzed by mass spectrometry, and the molecular m / z was determined to be 1070.55.

[0126] Synthesis Example 10

[0127] The method for synthesizing organic electroluminescent compound III-3 includes the following steps:

[0128] Synthesis of organic electroluminescent compound III-3: Under nitrogen protection, dry toluene (100 mL), the brominated compound shown in M-1-1 (5.86 g, 0.01 mol), the compound shown in formula III-3-2 (6.75 g, 0.021 mol), Pd(dba)2 (bis(dibenzylacetone palladium(0)), 0.0575 g, 0.0001 mol), a 10% toluene solution of tri-tert-butylphosphine (0.4 g, tri-tert-butylphosphine: 0.0002 mol), and sodium tert-butoxide (1.44 g, 0.015 mol) were added to a 250 mL three-necked flask. The mixture was heated to reflux for 24 hours, cooled, and water was added to obtain an organic layer. The organic layer was washed with water until neutral, dried over magnesium sulfate, filtered to remove magnesium sulfate, concentrated to dryness, separated by silica gel column chromatography, and eluted with petroleum ether to obtain organic electroluminescent compound III-3 (9.1 g).

[0129] The organic electroluminescent compound III-3 was detected by mass spectrometry, m / z: 1066.52.

[0130] NMR analysis was performed on organic electroluminescent compound III-3, and the data are analyzed as follows: 1 H-NMR (Bruker, Switzerland, Avance II 400MHz nuclear magnetic resonance spectrometer, CDCl3) δppm: 7.88~7.83 (m, 4H), δ7.79 (d, 2H), δ7.78~7.72 (m, 8H), δ7.58~7.42 (m, 20H), δ7.41~7.34 (m, 10H), δ6.70 (d, 2H), δ6.45 (m, 2H), δ1.27 (s, 18H).

[0131] Synthesis Example 11

[0132] The method for synthesizing the organic electroluminescent compound III-8 includes the following steps:

[0133] Synthesis of organic electroluminescent compound III-8: simply replace intermediate III-3-2 with intermediate III-8-2 to obtain organic electroluminescent compound III-8.

[0134] The organic electroluminescent compound III-8 was detected by mass spectrometry, with an m / z of 1094.48.

[0135] Synthesis Example 12

[0136] The method for synthesizing the organic electroluminescent compound III-23 includes the following steps:

[0137] Synthesis of organic electroluminescent compound III-23: The synthesis steps of organic electroluminescent compound III-3 in Synthesis Example 10 were followed, except that intermediate III-3-2 was replaced with intermediate III-23-2 to obtain organic electroluminescent compound III-23.

[0138] The organic electroluminescent compound III-23 was detected by mass spectrometry, with m / z values ​​of 1245.58 (intensity 100.0%) and 1244.58 (intensity 98.6%).

[0139] Synthesis Example 13

[0140] The method for synthesizing the organic electroluminescent compound III-45 includes the following steps:

[0141] Synthesis of intermediate III-45-1: Refer to the synthesis steps of intermediate II-3-1 in Synthesis Example 8, except that the compound shown in M-1-1 is replaced with the compound shown in M-62-1, and the compound shown in II-3-0 is replaced with diphenylamine to obtain intermediate III-45-1.

[0142] Mass spectrometry analysis was performed on intermediate III-45-1. The two largest m / z peaks were found at 725.27 and 727.26, confirming the product's molecular formula as C. 49 H 44 BrN.

[0143]

[0144] Synthesis of organic electroluminescent compound III-45: Following the synthesis steps of intermediate II-3-1 in Synthesis Example 8, except that the compound shown in M-1-1 is replaced with intermediate III-45-1, and the compound shown in II-3-0 is replaced with the compound shown in III-45-2, to obtain organic electroluminescent compound III-45.

[0145] The organic electroluminescent compound III-45 was detected by mass spectrometry, m / z: 966.49.

[0146] Synthesis Example 14

[0147] The method for synthesizing the organic electroluminescent compound III-62 includes the following steps:

[0148] Synthesis of organic electroluminescent compound III-62: Following the synthesis of organic electroluminescent compound III-3 in Example 10, only the types of corresponding brominated compounds and diarylamines were changed to obtain organic electroluminescent compound III-62.

[0149] Mass spectrometry was used to detect the organic electroluminescent compound III-62, and the molecular m / z was determined to be 966.49.

[0150] Other organic electroluminescent compounds for which specific synthesis steps are not listed can be prepared using common knowledge in the art, in conjunction with the above examples. Examples of organic electroluminescent devices

[0151] The specific structures of several materials used in the embodiments of organic electroluminescent devices are as follows:

[0152]

[0153]

[0154]

[0155] Performance testing of organic electroluminescent devices: The organic electroluminescent devices were tested at a brightness of 1000 cd / m² using an OLED-1000 multi-channel accelerated aging lifetime and photochromic performance analysis system manufactured by Hangzhou Yuanfang Instrument Co., Ltd. 2 Drive voltage and current efficiency at a brightness of 5000 cd / m² 2 Current efficiency and initial luminance at that time were 1000 cd / m². 2 LT95 at that time.

[0156] LT95 refers to the time required for the brightness of an organic electroluminescent device to drop to 95% of its initial brightness while maintaining a constant current density of 1000 cd / m2.

[0157] Based on a brightness of 1000 cd / m 2 The current efficiency η1 at a brightness of 5000 cd / m 2The current efficiency η2 is used to calculate the efficiency roll-off. The formula for calculating the efficiency roll-off is as follows: .

[0158] Examples 1-8 and Comparative Examples 1-3 The organic electroluminescent devices in Examples 1-8 and Comparative Examples 1-3 have the following structure: ITO / HIL02 (100nm) / hole transport material (40nm) / EM1 (30nm):BD[5%] / TPBI (30nm) / LiF (0.5nm) / Al (150nm), where “BD[5%]” refers to the doping ratio of BD, that is, the volume ratio of EM1 to BD is 100:5.

[0159] The specific fabrication process of the organic electroluminescent devices in Examples 1-8 and Comparative Examples 1-3 includes the following steps: (1) Pretreatment of ITO glass substrate: First, the ITO glass substrate coated with the ITO anode layer was ultrasonically treated in a cleaning agent, followed by rinsing with deionized water. Then, the ITO glass substrate was ultrasonically treated in a mixed solvent of acetone and ethanol, followed by baking in a clean environment at 120°C until completely dehydrated. Next, the dried ITO glass substrate was treated in an ozone ultraviolet irradiation instrument for 15 minutes. Finally, the surface of the ITO anode layer was bombarded with a low-energy cation beam to improve the surface properties of the ITO anode layer, thereby enhancing the bonding ability between the ITO anode layer and the hole injection layer. (2) Fabrication of organic electroluminescent devices: Place the glass substrate inside the vacuum chamber and evacuate to a vacuum level of 1×10⁻⁶. -6 ~9×10 -5 Pa; A hole injection layer was vacuum-deposited on the ITO anode layer. The material of the hole injection layer was HIL02, the deposition rate was 0.01 nm / s, and the deposition thickness was 100 nm. A hole transport layer was vacuum-deposited on the hole injection layer at a deposition rate of 0.01 nm / s and a deposition thickness of 40 nm. A light-emitting layer was vacuum-deposited on the hole transport layer. The materials of the light-emitting layer were EM1 and BD with a volume ratio of 100:5. The deposition rate was 0.01 nm / s and the deposition thickness was 30 nm. An electron transport layer was vacuum-deposited on the light-emitting layer. The electron transport layer was made of TPBI, the deposition rate was 0.01 nm / s, and the deposition thickness was 30 nm. An electron injection layer is vacuum-deposited on the electron transport layer. The electron injection layer is made of LiF, the deposition rate is 0.01 nm / s, and the deposition thickness is 0.5 nm. A cathode layer is vacuum-deposited on the electron injection layer. The cathode layer is made of Al, the deposition rate is 0.5 nm / s, and the deposition thickness is 150 nm.

[0160] The only difference between Examples 1-8 and Comparative Examples 1-3 is the hole transport material in the hole transport layer. The hole transport materials and performance test results of the organic electroluminescent devices of Examples 1-8 and Comparative Examples 1-3 are shown in Table 1.

[0161] Table 1. Hole transport materials and performance test results of organic electroluminescent devices in Examples 1-8 and Comparative Examples 1-3. project Hole transport layer material <![CDATA[Driving voltage (V) at a brightness of 1000 cd / m 2 > <![CDATA[Current efficiency (cd / A) at a brightness of 1000 cd / m 2 > <![CDATA[Current efficiency (cd / A) at a brightness of 5000 cd / m 2 > Efficiency rollover <![CDATA[LT95(h) at an initial brightness of 1000 cd / m 2 > Comparative Example 1 HT-1 4.38 5.02 4.01 20.12% 35 Comparative Example 2 HT-2 4.53 5.00 3.88 22.40% 60 Comparative Example 3 HT-3 5.11 3.86 2.88 25.39% 41 Example 1 II-3 3.95 5.11 5.01 1.96% 182 Example 2 II-4 3.88 5.21 5.18 0.58% 179 Example 3 II-25 3.99 5.02 4.91 2.19% 188 Example 4 II-54 3.91 5.42 5.31 2.03% 259 Example 5 III-3 4.62 5.11 5.09 0.39% 61 Example 6 III-8 4.11 4.98 4.88 2.01% 58 Example 7 III-45 4.56 5.15 5.08 1.36% 122 Example 8 III-62 4.88 5.55 5.45 1.80% 138 As can be seen from Table 1, compared with the compounds shown in Formula HT-1, Formula HT-2 and Formula HT-3, the organic electroluminescent device of this application, by using the organic electroluminescent compound provided in this application as the hole transport material, can improve luminous efficiency, reduce driving voltage, extend service life and significantly reduce efficiency roll-off.

[0162] Examples 9-16 and Comparative Example 4 The structures and specific fabrication processes of the organic electroluminescent devices in Examples 9-16 and Comparative Example 4 are the same as those in Examples 1-8 and Comparative Examples 1-3, except for the hole transport materials. The hole transport materials and performance test results of the organic electroluminescent devices in Examples 9-16 and Comparative Example 4 are shown in Table 2.

[0163] Table 2. Hole transport materials and performance test results of organic electroluminescent devices in Examples 9-16 and Comparative Example 4.

[0164] As can be seen from Table 2, compared with the compound shown in Formula HT-4, the organic electroluminescent device of this application can improve luminous efficiency, reduce driving voltage, and significantly extend service life by using the organic electroluminescent compound provided in this application as the hole transport material.

[0165] Examples 17-18 and Comparative Example 5 The organic electroluminescent devices in Examples 17-18 and Comparative Example 5 have the following structure: ITO / NPB (20nm) / red light host material (35nm): Ir(piq)3 [10%] / TPBI (10nm) / Alq3 (15nm) / LiF (0.5 nm) / Al (150nm), where "Ir(piq)3 [10%]" refers to the doping ratio of the red light dye Ir(piq)3, that is, the weight ratio of the red light host material to Ir(piq)3 is 100:10.

[0166] The specific fabrication process of the organic electroluminescent devices in Examples 17-18 and Comparative Example 5 includes the following steps: (1) Pretreatment of ITO glass substrate: First, the ITO glass substrate coated with the ITO anode layer was ultrasonically treated in a cleaning agent, followed by rinsing with deionized water. Then, the ITO glass substrate was ultrasonically treated in a mixed solvent of acetone and ethanol, and then baked in a clean environment at 120°C until completely dehydrated. Next, the dried ITO glass substrate was treated in an ozone ultraviolet irradiation instrument for 15 minutes. Finally, the surface of the ITO anode layer was bombarded with a low-energy cation beam to improve the surface properties of the ITO anode layer, thereby enhancing the bonding ability between the ITO anode layer and the hole transport layer. (2) Fabrication of organic electroluminescent devices: Place the glass substrate inside the vacuum chamber and evacuate to a vacuum level of 1×10⁻⁶. -6 ~9×10 -5 Pa; A hole transport layer was vacuum-deposited on the ITO anode layer. The hole transport layer was made of NPB, the deposition rate was 0.01 nm / s, and the deposition thickness was 20 nm. A light-emitting layer was vacuum-deposited on the hole transport layer. The material of the light-emitting layer was a red light host material and dye Ir(piq)3 with a weight ratio of 100:10. The deposition rate was 0.01 nm / s and the deposition thickness was 35 nm. A first electron transport layer is vacuum-deposited on the light-emitting layer. The material of the first electron transport layer is TPBI, the deposition rate is 0.01 nm / s, and the deposition thickness is 10 nm. A second electron transport layer is vacuum-deposited on the first electron transport layer. The material of the second electron transport layer is Alq3, the deposition rate is 0.01 nm / s, and the deposition thickness is 15 nm. An electron injection layer was vacuum-deposited on the second electron transport layer. The electron injection layer was made of LiF, the deposition rate was 0.01 nm / s, and the deposition thickness was 0.5 nm. A cathode layer is vacuum-deposited on the electron injection layer. The cathode layer is made of Al, the deposition rate is 0.5 nm / s, and the deposition thickness is 150 nm.

[0167] Performance testing of organic electroluminescent devices in Examples 17-18 and Comparative Example 5: The organic electroluminescent devices were tested at a brightness of 1000 cd / m² using an OLED-1000 multi-channel accelerated aging lifetime and photochromic performance analysis system manufactured by Hangzhou Yuanfang Instrument Co., Ltd. 2 The driving voltage and current efficiency at that time.

[0168] The only difference between Examples 17-18 and Comparative Example 5 is the different red light host materials. The red light host materials and performance test results of the organic electroluminescent devices of Examples 17-18 and Comparative Example 5 are shown in Table 3.

[0169] Table 3. Red light host material and performance test results of organic electroluminescent devices in Examples 17-18 and Comparative Example 5. project Red light main material <![CDATA[Required luminance (cd / m 2 )]]> Drive voltage (V) Current efficiency (cd / A) Comparative Example 5 HT-1 1000 8.11 11.01 Example 15 III-22 1000 5.02 39.11 Example 15 III-23 1000 5.61 36.51 As can be seen from Table 3, compared with the compound shown in Formula HT-1, the organic electroluminescent device of this application can improve luminous efficiency and reduce driving voltage by using the organic electroluminescent compound provided in this application as the red light host material.

[0170] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. An organic electroluminescent compound, characterized in that, The structure of the organic electroluminescent compound is shown in formula (I): In equation (I), X and Y are each independently selected from... , , , , , , , , , , , , , ; Ar1, Ar2, Ar3, and Ar4 are each independently selected from benzene, biphenyl, 9,9-dimethylfluorene, dibenzofuran, and carbazole; and at least one substituent in Ar1, Ar2, Ar3, and Ar4 is selected from C12 to C24 aryl groups; A and B are each independently selected from benzene and biphenyl, and m and n are each independently selected from 0 and 1; The compound shown in formula (I) can be substituted with C6-C60 aryl groups.

2. The organic electroluminescent compound according to claim 1, characterized in that, Ar1, Ar2, Ar3, and Ar4 are each independently selected from one of the following monovalent organic groups: 。 3. The organic electroluminescent compound according to claim 1, characterized in that, m+n=0.

4. The organic electroluminescent compound according to claim 1, characterized in that, The organic electroluminescent compound is one of the following compounds: 。 5. An organic electroluminescent device, characterized in that, It includes a cathode layer, an anode layer, and an organic layer located in the cathode layer and the anode layer, wherein the organic layer contains an organic electroluminescent compound as described in any one of claims 1 to 4.

6. The organic electroluminescent device according to claim 5, wherein the organic layer comprises a light-emitting layer and a hole transport layer located between the light-emitting layer and the anode layer; in, The hole transport layer contains the following compounds: 。 7. The organic electroluminescent device according to claim 5, characterized in that, The organic layer includes a light-emitting layer and a hole transport layer located between the light-emitting layer and the anode layer; The light-emitting layer contains the following compounds: 。

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