Organic electroluminescent material and organic electroluminescent device

[0037] First embodiment

[0038] The organic electroluminescent material according to the first embodiment of the present invention has the structure of the following formula (1).

[0039]

[0040] The structure of the above formula (1) is a polycyclic nitrogen-containing heterocyclic organic compound, when R 2 , R 4 , R 6 , R 9 Or R 13 When they are all independent hydrogen atoms, the structure of formula (1) is N-phenylcarbazole (NPC), which is a carbazole derivative, or carbazole group. In this embodiment, R 2 , R 4 , R 6 , R 9 Or R 13 One or two of them can be independent triazole derivatives. The triazole derivatives described in this embodiment are derivatives with the structure of the following formula (2).

[0041]

[0042] That is, this embodiment uses the nitrogen atom on the triazole derivative to connect to the N-phenylcarbazole R 2 , R 4 , R 6 , R 9 Or R 13 One or two of them to form a double dipole molecule with a high triplet energy state, that is, the organic electroluminescent material of this embodiment. When R 2 , R 4 , R 6 , R 9 Or R 13 When one or two of them are triazole derivatives, the other substituents may be hydrogen atoms, fluorine atoms, cyano groups, alkyl groups, cycloalkyl groups, alkyloxy groups, The sulfanyl group, silyl group, or alkenyl group is not limited in the present invention.

[0043] Specifically, when R 2 Is a triazole derivative, R 1 , And R 3 To R 23 One selected from independently hydrogen atom, fluorine atom, cyano group, alkyl group, cycloalkyl group, alkoxy group, sulfanyl group, silyl group, and alkenyl group; when R 4 Is a triazole derivative, R 1 To R 3 , And R 5 To R 23 One selected from independently hydrogen atom, fluorine atom, cyano group, alkyl group, cycloalkyl group, alkoxy group, sulfanyl group, silyl group, and alkenyl group; when R 9 Is a triazole derivative, R 1 To R 8 , And R 10 To R 23 One selected from independently hydrogen atom, fluorine atom, cyano group, alkyl group, cycloalkyl group, alkoxy group, sulfanyl group, silyl group, and alkenyl group; when R 2 And R 6 Is a triazole derivative, R 1 , R 3 To R 5 , And R 7 To R 23 One selected from independently hydrogen atom, fluorine atom, cyano group, alkyl group, cycloalkyl group, alkoxy group, sulfanyl group, silyl group, and alkenyl group; and when R 9 And R 13 Is a triazole derivative, R 1 To R 8 , R 10 To R 12 , And R 14 To R 23 It is selected from one of independently hydrogen atoms, fluorine atoms, cyano groups, alkyl groups, cycloalkyl groups, alkoxy groups, sulfanyl groups, silyl groups, and alkenyl groups.

[0044] In this embodiment, the alkyl group may be a substituted straight chain alkyl group having 1 to 6 carbons, an unsubstituted straight chain alkyl group having 1 to 6 carbons, a substituted branched chain alkyl group having 1 to 6 carbons, Or an unsubstituted branched alkyl group having 1 to 6 carbon atoms. The cycloalkyl group may be a substituted cycloalkyl group having 1 to 6 carbon atoms, or an unsubstituted cycloalkyl group having 1 to 6 carbon atoms. The alkoxy group may be a substituted linear alkoxy group having 1 to 6 carbons, an unsubstituted linear alkoxy group having 1 to 6 carbons, a substituted branched alkoxy group having 1 to 6 carbons, or a carbon An unsubstituted branched chain alkoxy group of 1 to 6. The sulfanyl group may be a substituted linear sulfanyl group having 1 to 6 carbons, an unsubstituted linear sulfanyl group having 1 to 6 carbons, a substituted branched sulfanyl group having 1 to 6 carbons, or a carbon An unsubstituted branched chain sulfanyl group of 1 to 6. The silyl group may be a substituted linear silyl group having 1 to 6 carbons, an unsubstituted linear silyl group having 1 to 6 carbons, a substituted branched silyl group having 1 to 6 carbons, or a carbon number of 1 to 6 The unsubstituted branched silyl group. The alkenyl group may be a substituted straight chain alkenyl group having 1 to 6 carbons, an unsubstituted straight chain alkenyl group having 1 to 6 carbons, a substituted branched chain alkenyl group having 1 to 6 carbons, or a substituted branched chain alkenyl group having 1 to 6 carbons. The unsubstituted branched alkenyl group of 6 is not limited in the present invention.

[0045] For example, the organic electroluminescent material according to this embodiment is, for example, a compound having the following structural formula:

[0046]

[0047]

[0048] Among them, compound O-1 is when R 9 Is a triazole derivative, R 1 To R 8 , And R 10 To R 23 Is the structural formula of independent hydrogen atoms, compound O-2 is when R 2 Is a triazole derivative, R 1 , And R 3 To R 23 Is the structural formula of independent hydrogen atoms, compound O-3 is when R 4 Is a triazole derivative, R 1 To R 3 , And R 5 To R 23 Selected as the structural formula of independent hydrogen atoms, compound O-4 is when R 2 And R 6 Is a triazole derivative, R 1 , R 3 To R 5 , And R 7 To R 23 Is the structural formula of independent hydrogen atoms, compound O-5 is when R 9 And R 13 Is a triazole derivative, R 1 To R 8 , R 10 To R 12 , And R 14 To R 23 It is the structural formula of independent hydrogen atoms.

[0049] As mentioned above, the organic electroluminescent material of this embodiment is a carbazole derivative, which uses the ortho-substitution method of the benzene ring to stagger the two aromatic groups in space by steric barriers, even if the carbazole group (The compound of formula (1)) and the triazole group (the compound of formula (2)) are mutually staggered in space, which reduces the conjugation system of the entire molecule, thereby enabling organic electroluminescent materials to have a higher triplet energy gap And the polyphenyl ring structure of carbazole derivatives has good thermal stability.

[0050] Second embodiment

[0051] figure 2 It is a schematic diagram of the organic electroluminescence device of the second embodiment of the present invention, please refer to figure 2 Shown. The organic electroluminescence device 2 of this embodiment includes a first electrode layer 21, a second electrode layer 22, and an organic light emitting unit 23, wherein the organic light emitting unit 23 is disposed on the first electrode layer 21 and the second electrode layer 22 between. Wherein, the organic light emitting unit 23 includes at least one organic electroluminescent material, and the organic electroluminescent material is the organic electroluminescent material (carbazole derivative) described in the first embodiment, so the details can refer to the first embodiment As mentioned in the examples, I will not repeat them here.

[0052] In this embodiment, the first electrode layer 21 is disposed on the substrate 24, where the substrate 24 is selected from at least one of a rigid substrate, a flexible substrate, a glass substrate, a plastic substrate, and a silicon substrate. The flexible substrate and the plastic substrate can be polycarbonate (PC) substrate, polyester (PET) substrate, cyclic olefin copolymer (COC) substrate or metallocene-based cyclic olefin Copolymer (metallocene-based cyclicolefin copolymer, mCOC), polymethyl methacrylate, polymer substrate, etc. The first electrode layer 21 may be formed on the substrate 24 by sputtering, ion plating, or the like. The first electrode layer 21 is often used as an anode and its material is usually a transparent electrode material, such as indium tin oxide (ITO), aluminum zinc oxide (AZO), or indium zinc oxide (IZO). The second electrode layer 22 may be a conductive material, and its material may be selected from at least one of aluminum, calcium, magnesium, indium, tin, manganese, copper, silver, gold, and alloys thereof. The alloy containing magnesium is, for example, magnesium Silver alloy, magnesium indium alloy, magnesium tin alloy, magnesium antimony alloy or magnesium tellurium alloy, etc. In this embodiment, the first electrode layer 21 is a transparent electrode material, and the second electrode layer 22 can be, for example, a metal. The materials of the first electrode layer 21 and the second electrode layer 22 and the application as a cathode and anode can be Exchange according to actual needs. On the whole, at least one of the first electrode layer 21 or the second electrode layer 22 of this embodiment is made of a transparent electrode material, so that the light emitted by the organic light-emitting unit 23 can pass through the transparent electrode, thereby causing the organic electro The light-emitting device 2 achieves a light-emitting effect.

[0053] In this embodiment, the organic light emitting unit 23 uses, for example, evaporation, molecular beam evaporation (MBE), immersion, spin coating, casting, and roll coating. (roll coating), printing, ink jet printing, transfer, etc. are formed on the first electrode layer 21. In addition, the second electrode layer 22 is disposed on the organic light emitting unit 23. Here, the second electrode layer 22 can be formed on the organic light-emitting unit 23 using methods such as evaporation or sputtering.

[0054] Preferably, the organic light emitting unit 23 of this embodiment further includes a hole transport layer 231, an exciton blocking layer 232, an organic light emitting layer 233, an electron transport layer 234, and an electron injection layer 235. Such as figure 2 As shown, a hole transport layer 231, an exciton blocking layer 232, an organic light emitting layer 233, an electron transport layer 234, and an electron injection layer 235 are sequentially arranged between the first electrode layer 21 and the second electrode layer 22. In other words, the hole transport layer 231 and the electron injection layer 235 are connected to the first electrode layer 21 and the second electrode layer 22, respectively, and the exciton blocking layer 232 and the organic The light-emitting layer 233 and the electron transport layer 234. Of course, in other embodiments, the organic light emitting unit may also be a structure composed of a hole transport layer, an organic light emitting layer and an electron transport layer, and the organic light emitting layer is disposed between the hole transport layer and the electron transport layer.

[0055] In this embodiment, the hole transport layer 231 is located between the first electrode layer 21 and the exciton blocking layer 232. The material of the hole transport layer 231 can be composed of any triphenylamine material, which can be, for example, 4,4'-bis[N-(1-naphthyl)-N-anilinobiphenyl (NPB) or 3-tryptoimino-1-phenyl-butan-1-one (TPB), etc., and The thickness of the hole transport layer 231 of this embodiment is, for example, in the range of 0.1 nm to 100 nm. The hole transport layer 231 may promote the transfer of holes from the first electrode layer 21 to the organic light emitting layer 233 to increase the transfer rate of holes.

[0056] The exciton blocking layer 232 is disposed between the hole transport layer 231 and the organic light emitting layer 233. Among them, the material of the exciton blocking layer 232 is, for example, 1,3-bis(carbazol-9-yl)benzene (mCP) or other materials with a high triplet energy gap. In this embodiment, the thickness of the exciton blocking layer 232 is in the range of, for example, 0.1 nm to 30 nm. The exciton blocking layer 232 can prevent excitons from diffusing from the organic light emitting layer 233 to close to the first electrode layer 21 and being quenched.

[0057] The organic light-emitting layer 233 is located between the exciton blocking layer 232 and the electron transport layer 234. The thickness of the organic light-emitting layer 233 of this embodiment can be between 5 nm and 60 nm, and the organic light-emitting layer 233 includes a host material and a guest material. The aforementioned organic electroluminescent material is the organic electroluminescent material (carbazole derivative) described in the first embodiment. Preferably, the organic electroluminescent material is one of the aforementioned compounds O-1 to O-5, or any combination thereof, and the present invention is not limited. The guest material in this embodiment is a phosphorescent light-emitting material, and can be any light-emitting material suitable for use in an organic light-emitting layer of an organic electroluminescent device, and it may be, for example, not limited to Ir(2-phq) 3 , Ir(ppy) 3 , Or FIrpic, the structures of which are shown in formula (3), formula (4), and formula (5) respectively.

[0058]

[0059] Preferably, the content of the host material in the organic light-emitting layer 233 of this embodiment is between 60% and 95% by volume, and the content of the guest material in the organic light-emitting layer 233 is between 5% and 40% by volume.

[0060] The electron transport layer 234 of this embodiment is disposed between the organic light-emitting layer 233 and the electron injection layer 235. The material of the electron transport layer 234 can be, for example, but not limited to, metal complexes such as AlQ and BeBq2, or PBD, TAZ, TPBI, Heterocyclic compounds such as DPPS. In this embodiment, the thickness of the electron transport layer 234 may be between 0.1 nm and 100 nm. The electron transport layer 234 may promote the transfer rate of electrons from the electron injection layer 235 to the organic light emitting layer 233.

[0061] In addition, the organic electroluminescent material of this embodiment can be used as the host material of the organic light-emitting layer 233, and can also be used for other film layers in the organic light-emitting unit 23, such as the hole transport layer 231, the exciton blocking layer 232, An electron transport layer 234 and an electron injection layer 235. In other embodiments, when the organic light emitting unit has a hole injection layer and a hole blocking layer, the organic electroluminescent material of this embodiment can also be applied to the film layers, and the invention is not limited.

[0062] In the organic electroluminescence device 3, if the luminous efficiency of the organic light-emitting layer 233 is to be improved, the triplet energy gap of the host material must be higher than the triplet energy gap of the guest material, so as to avoid energy return and cause organic electroluminescence. The luminous efficiency of the light-emitting device decreases. In this embodiment, the organic electroluminescent material (carbazole derivative) is used as the host material, which can have a higher triplet energy gap, thereby preventing energy from being transmitted back from the guest material, and improving the luminescence of the organic electroluminescent device effectiveness.

[0063] In order to make the content of the above-mentioned embodiments easier to understand, several examples will be given below to illustrate the synthesis method of the organic electroluminescent material and the manufacturing process of the organic electroluminescent device.

[0064] Example one : Synthesis of Compound O-1

[0065]

[0066] Take carbazole (compound 1, 0.30g, 1.8mmol), 1-fluoro-3-nitrobenzene (1-fluoro-3-nitrobenzene, 0.25g, 1.8mmol), dimethylsulfoxide (5mL) Put it in a single-necked bottle (10mL). After stirring with a magnetic stir bar until the solid is dissolved, cesium carbonate (0.64 g, 2.0 mmol) is added and reacted at room temperature for 18 hours. Then, after adding deionized water (5 mL), a yellow solid was produced, which was extracted three times with chloroform (30 mL). The organic layer was collected and washed with deionized water (30 mL) three times. The organic layer was dried with anhydrous magnesium sulfate Then, the solvent was removed by vortex concentration to obtain compound 2 (0.49g) with a yield of 94%.

[0067] Next, take compound 2 (2.0g, 6.9mmol), tin(II) chloride dihydrate (7.83g, 34.7mmol), ethyl acetate (34.5mL), ethanol (34.5 mL) was placed in a single-necked flask (250 mL) and stirred with a magnetic stir bar. Then, the condenser tube on the shelf was heated to 90°C and refluxed for 10 hours. After the solution returned to room temperature, it was poured into a 2M potassium hydroxide aqueous solution and extracted with ethyl acetate. The organic layer was collected and dried with anhydrous magnesium sulfate. Then, the solvent was removed by vortex concentration to obtain compound 3 (1.77 g) with a yield of 99%.

[0068] Finally, take compound 3 (0.32g, 1.2mmol), N'-(chloro(phenyl)methylene)benzohydrazino chloride (0.34g, 1.2mmol), triethylamine (triethylamine, 0.35mL, 2.4mmol), dimethylformamide (N,N-dimethylforamide, 0.19mL, 2.4mmol), p-xylene (12mL) were placed in a single-necked flask (25mL). Stir with a magnetic stir bar, and heat to 160°C and reflux for 34 hours on a condenser tube. Next, the solvent was distilled off under reduced pressure, and after heating and stirring with acetone for several hours, a white solid was precipitated by suction filtration. Finally, recrystallize with dichloromethane and ethanol to obtain compound 4, which is compound O-1 (0.24 g), with a yield of 42%.

[0069] The spectral data are as follows: 1 H NMR (400MHz, CD 2 Cl 2 )δ7.94(d,J=7.8Hz,2H),7.91-7.89(m,1H),7.77-7.70(m,2H),7.56-7.53(m,1H),7.28(tt,J=7.2Hz ,1.4Hz,2H),7.24-7.22(m,4H),7.19-7.15(m,4H),7.11(t,J=7.8Hz,2H),6.91-6.87(m,2H),6.35(d, J=8.3Hz, 2H); 13 C NMR(100MHz, CDCl 3 )δ154.32,140.22,135.01,132.82,131.91,131.75,131.42,129.90,128.92,128.55,128.44,126.87,125.97,123.66,120.35,119.94,109.27.HRMS(EI)m/z C 32 H 22 N 4 The calculated value of 462.1839, the observed value of 462.1838.Anal.C 32 H 22 N 4 Calculated value for: C, 83.09; H, 4.79; N, 12.11. Found value: C, 82.96; H, 4.79; N, 12.10.