An organic electroluminescent compound with a triazine group and an organic light-emitting device

Abstract

The present invention discloses an organic electroluminescent compound containing a triazine group and an organic light-emitting device. The compound is selected from the compound represented by Formula 1: #imgabs0#, wherein R1-R26 is selected from hydrogen, deuterium, hydroxyl, cyano, C1-C4 linear or branched alkyl, C5-C6 cycloalkyl, substituted or unsubstituted C5-C40 aromatic group, or substituted or unsubstituted C5-C40 heteroaryl group; the substituent is selected from at least one of the following atoms or groups: deuterium, hydroxyl, cyano, monodeuteriomethyl, dideuteriomethyl, trideuteriomethyl, C1-C4 linear or branched alkyl, C6-C18 aromatic group, or C5-C24 heteroaryl group; and at least one of R1-R8 is deuterium. The present invention reduces molecular vibration and improves luminous efficiency by deuterating the carbazole. The present invention provides a phenyl group connected to the ortho position of carbazole on the transition phenyl group. This structural design helps to promote energy transfer within the molecule, thereby improving energy utilization efficiency and luminous efficiency. The introduction of deuterated carbazole and ortho-biphenyl improves the chemical stability of the compound and helps to increase the service life of the device.

Description

Technical Field

[0001] The present invention relates to the technical field of organic electroluminescence, and in particular to an organic electroluminescent compound with a triazine group and an organic light-emitting device. Background Art

[0002] Organic light-emitting diodes (OLEDs) are a display technology that uses an electric field to stimulate the emission of fluorescent materials. Their operating principle is that, under the influence of an electric field, holes injected from the positive electrode recombine with electrons injected from the negative electrode in the light-emitting layer, generating light. OLEDs, with their advantages such as low startup voltage, high brightness, wide viewing angle, fast response, and good temperature adaptability, are widely used in mobile phones, tablet computers, TV displays, and lighting.

[0003] OLEDs have a sandwich-like structure, consisting of multiple layers of organic materials with different functions sandwiched between two electrodes. These layers include a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer. Each layer plays a key role in improving the overall efficiency and stability of the device. To further enhance OLED performance, research efforts are focused on reducing driving voltage, enhancing luminous efficiency, and extending lifetime.

[0004] The advancement of OLED technology relies not only on innovations in device design and manufacturing processes, but also on the continued research and development of organic light-emitting materials. The development of new, high-performance organic light-emitting materials is crucial for the continued development and application expansion of OLED technology.

[0005] The invention patent with publication number "CN113493446A" discloses an organic electroluminescent compound based on carbazole and an organic electroluminescent device. The general formula of the compound is as follows: The substituents are defined as follows (wherein, R1 and R2 are each independently a C6-C30 aromatic hydrocarbon group, at least one C in the C6-C30 aromatic hydrocarbon group is substituted or unsubstituted by N; L is any one of phenylene, biphenylene, and terphenylene; Ar1 and Ar2 are each independently hydrogen, a substituted or unsubstituted C6-C30 aromatic hydrocarbon group, or a substituted or unsubstituted C5-C60 heteroaromatic hydrocarbon group; R3, R4, R5, R6, R7, R8, R9, R 10Each independently represents hydrogen, deuterium, cyano, substituted or unsubstituted C1-C30 straight or branched alkyl, substituted or unsubstituted C2-C30 straight or branched alkenyl, substituted or unsubstituted C2-C30 straight or branched alkynyl, substituted or unsubstituted C6-C30 aromatic hydrocarbon, substituted or unsubstituted C5-C60 heteroaromatic hydrocarbon, substituted or unsubstituted C12-C30 diarylamino, substituted or unsubstituted C10-C30 diheteroarylamino, substituted or unsubstituted C10-C30 arylheteroarylamino; X, Y, and Z are each independently CH or N, and at least one of X, Y, and Z is N. The patent discloses the application of the above-mentioned compound materials in a two-component green light host material, and discloses the following specific structure:

[0006] The invention patent publication number "CN116457351A" discloses the following general formula compound: And discloses the following specific compounds This patent compares the above compounds with non-deuterated carbazole compounds. The organic light-emitting devices of the embodiments using the above compounds as the main materials of the light-emitting layer show significantly improved life characteristics without reducing efficiency. With the development and progress of materials, further development is now needed based on the above compounds to obtain organic electroluminescent compounds with better performance. Summary of the Invention

[0007] The purpose of the present invention is to solve the above technical problems. The present invention provides an organic electroluminescent compound selected from the compound shown in Formula 1:

[0008]

[0009] Among them, R1-R 26 is selected from hydrogen, deuterium, hydroxyl, cyano, C1-C4 straight or branched alkyl, C5-C6 cycloalkyl, substituted or unsubstituted C5-C40 aromatic group, substituted or unsubstituted C5-C40 heteroaryl group, the substituent is selected from at least one of the following atoms or groups: deuterium, hydroxyl, cyano, monodeuteriomethyl, dideuteriomethyl, trideuteriomethyl, C1-C4 straight or branched alkyl, C6-C18 aromatic group, C5-C24 heteroaryl group, at least one of R1-R8 is deuterium.

[0010] As a preferred embodiment of the present invention, R1-R 26Each is independently selected from hydrogen, deuterium, cyano, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, phenyl, anthracenyl, naphthyl, and phenanthryl; the methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, phenyl, anthracenyl, naphthyl, and phenanthryl are unsubstituted or are groups in which at least one hydrogen is replaced by deuterium, a deuterated or non-deuterated C1-C4 straight or branched alkyl group, or a deuterated or non-deuterated phenyl group, and at least one of R1-R8 is deuterium.

[0011] In a preferred embodiment, R1-R8 are selected from deuterium, phenyl and at least 7 of R1-R8 are deuterium, R9-R 26 Each is independently selected from hydrogen, deuterium, cyano, methyl, ethyl, propyl, isopropyl, phenyl, anthracenyl, naphthyl or phenanthrenyl, wherein the methyl, ethyl, propyl, isopropyl, phenyl, anthracenyl or phenanthrenyl is unsubstituted or a group in which at least one hydrogen is replaced by deuterium, deuterated or non-deuterated C1-C4 straight or branched alkyl, deuterated or non-deuterated phenyl.

[0012] Preferably, the compound is selected from the compounds shown in Formula 2 to Formula 6:

[0013]

[0014] Among them, R9-R 26 Each is independently selected from hydrogen, deuterium, cyano, methyl, ethyl, phenyl, anthracenyl or phenanthrenyl; the methyl, ethyl, phenyl, anthracenyl or phenanthrenyl is unsubstituted or a group in which at least one hydrogen is replaced by deuterium, a deuterated or non-deuterated C1-C4 straight or branched alkyl group, or a deuterated or non-deuterated phenyl group.

[0015] More preferably, R1-R8 are selected from deuterium, phenyl and at least 7 of R1-R8 are deuterium; R9-R 11 Each independently selected from hydrogen, deuterium; R 12 -R 16 Each independently selected from hydrogen, deuterium, phenyl, deuterated phenyl; R 17 -R 26 Each is independently selected from hydrogen, deuterium, phenyl, and deuterated phenyl.

[0016] As a preferred embodiment of the present invention, the organic electroluminescent compound having a triazine group is one of the following compounds:

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026] The present invention also provides an organic electroluminescent device, comprising a first electrode, a second electrode, and an organic layer formed between the first electrode and the second electrode, wherein the organic layer contains any one of the above-mentioned organic electroluminescent compounds.

[0027] As a preferred embodiment of the present invention, the organic layer comprises a hole injection layer, a hole transport layer, a second hole transport layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer; at least one of the hole injection layer, the hole transport layer, the second hole transport layer, the light-emitting layer, the hole blocking layer, the electron transport layer, and the electron injection layer contains the organic electroluminescent compound according to any one of claims 1 to 7.

[0028] As a preferred embodiment of the present invention, the light-emitting layer contains at least one of the organic electroluminescent compounds described above.

[0029] As a preferred embodiment of the present invention, the light-emitting layer further contains at least one of the following formula (7) or formula (8):

[0030]

[0031] wherein Y1 and Y2 are each independently a single bond, a substituted or unsubstituted C6 to C20 arylene group; Ar1 and Ar2 are each independently a substituted or unsubstituted C6 to C20 aryl group, a substituted or unsubstituted C2 to C24 heteroaryl group; Ar3 to Ar16 are each independently hydrogen, deuterium, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C6 to C20 aryl group, a substituted or unsubstituted C2 to C24 heteroaryl group, a cyano group, or a combination thereof, and the substituent is a C6 to C20 aryl group.

[0032] As a preferred embodiment of the present invention, the light-emitting layer contains a light-emitting host material, and the light-emitting host material is a mixture of the compound according to any one of claims 1 to 6 and one or more compounds G1 to G103, and the compounds G1 to G103 are as follows:

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039] The compound of the present invention having the structure shown in Formula 1 has a synthesis reaction route as follows:

[0040]

[0041]

[0042]

[0043] Beneficial effects of the present invention:

[0044] 1. The present invention reduces molecular vibration by deuterating carbazole, thereby reducing the non-radiative recombination rate and improving the luminescence efficiency. Since the zero-point vibration energy of the deuterium atom is low, it helps to increase the luminescence quantum yield and improve the luminescence performance of the organic molecule.

[0045] 2. The present invention incorporates a phenyl group ortho-linked to the carbazole group on the transitional phenyl group. This structural design facilitates intramolecular energy transfer, thereby improving energy utilization and luminescence efficiency. The introduction of deuterated carbazole and ortho-biphenyl enhances the chemical stability of the compound, further helping to extend the device's lifespan.

[0046] 3. By deuterating the carbazole and attaching an ortho-biphenyl to the triazine, the present invention modifies the compound's electronic structure, thereby affecting its luminescent color and spectral characteristics, helping to achieve efficient emission of a specific green light. As one component of a two-component green light host material, the improved compound complements the other components with excellent luminescent properties, achieving more efficient luminescence and improved color purity. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A schematic structural diagram of an organic electroluminescent device provided by the present invention;

[0048] The numbers in the figure represent: 1-anode, 2-hole injection layer, 3-hole transport layer, 4-second hole transport layer, 5-light-emitting layer, 6-hole blocking layer, 7-electron transport layer, 8-electron injection layer, 9-cathode.

[0049] Figure 2 The HPLC spectrum of compound 2 of the present invention is shown in FIG.

[0050] Figure 3 is the DSC spectrum of compound 2 of the present invention, Figure 3 It can be seen that the Tg value of compound 2 is 122.39°C.

[0051] Figure 4 is the TGA spectrum of compound 2 of the present invention, Figure 4 It can be seen that the thermal gravimetric loss temperature Td value of compound 2 is 393.57°C.

[0052] Figure 5 is the H-NMR spectrum of compound 2 of the present invention. DETAILED DESCRIPTION

[0053] The following further illustrates and describes embodiments of various aspects. It should be understood that the description herein is not intended to limit the claims to the specific aspects described. On the contrary, it is intended to cover alternatives, modifications, and equivalents that may be included within the spirit and scope of the present disclosure as defined by the appended claims.

[0054] As used herein, in "deuterated" or "undeuterated," the term "deuterated" means that at least one hydrogen in the group is re-coordinated with deuterium. The term "undeuterated" means that none of the hydrogens in the group are re-coordinated with deuterium.

[0055] As used herein, "aromatic group," "aryl," or "aromatic radical" refers to a group containing one or more aromatic rings, including but not limited to benzene, naphthalene, phenanthrene, fluorene, acenaphthene, pyridine, pyrimidine, pyrrole, furan, thiophene, and the like. The C5-C40 in a C5-C40 aromatic group means that the group contains 5-40 carbon atoms. Aromatic groups can be divided into monocyclic aromatic groups and polycyclic aromatic groups. Specific aromatic groups in the present invention include but are not limited to phenyl, biphenyl, terphenyl, anthracenyl, naphthyl, phenanthrenyl, fluorenyl, dibenzofuranyl, dibenzothiophenyl, 9,9-spirobifluorenyl, 9,9-dimethylfluorenyl, or 9,9-diphenylfluorenyl. Aromatic groups can be substituted or unsubstituted.

[0056] As used herein, "cycloalkyl" refers to a monocyclic or fused ring group ("fused" ring means that each ring in the system shares a pair of adjacent carbon atoms with the other rings in the system) that is entirely carbon, wherein one or more rings are saturated alicyclic rings, generally having 3-20 carbon atoms, preferably 3-12 carbon atoms, and more preferably 3-10 carbon atoms. Cycloalkyl groups can be divided into monocyclic alkyl groups having only one ring and fused cycloalkyl groups having multiple rings. Examples of monocyclic alkyl groups include, but are not limited to, cyclopropane, cyclobutane, cyclopentane, cyclohexane, and cycloheptane. Cycloalkyl groups can be substituted or unsubstituted.

[0057] "Cycloalkenyl" herein refers to a monocyclic or fused ring group ("fused" ring means that each ring in the system shares a pair of adjacent carbon atoms with the other rings in the system) of all carbon, wherein one or more rings do not have a completely connected π electron system and contain at least one alkenyl group, which generally has 3-20 carbon atoms, preferably 3-12 carbon atoms, more preferably 3-10 carbon atoms, and examples of cycloalkenyl groups include but are not limited to cyclopentene, cyclohexene, cyclohexadiene, and cycloheptatriene. Cycloalkenyl groups can be substituted or unsubstituted.

[0058] The "deuterated aromatic group" herein refers to an aromatic group in which one or more hydrogen atoms are replaced by deuterium.

[0059] The "deuterated phenyl group" herein refers to a group in which one or more hydrogen atoms in a phenyl group are replaced by deuterium.

[0060] The "heteroaryl" herein refers to a heteroaryl group obtained by replacing one or more carbon atoms in the structure of "aryl" with one or more heteroatoms (such as N, O or S).

[0061] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or those recommended by the manufacturer. All reagents or instruments used, if the manufacturer is not specified, are commercially available conventional products.

[0062] Example 1

[0063] Compound 2

[0064]

[0065] Compound 2 was prepared as follows:

[0066] Step S1:

[0067]

[0068] Process: Under nitrogen protection, deuterated carbazole SM-1 (35g, 0.2mol, 1eq), halide SM-2 (62.7g, 0.3mol, 1.5eq), DMF 400ml, and cesium carbonate (164g, 0.5mol, 2.5eq) were added to the reaction flask. After the addition was completed, the reaction solution was heated and refluxed for 12h, and the reaction was completed by sampling and HPLC detection.

[0069] Post-treatment: After the reaction solution is cooled, it is added to water, filtered, and the filter cake is washed with water and ethanol. After drying, about 44 g of product ZJ-1 is obtained, with a yield of 60%. Step S2:

[0070]

[0071] Process: Under nitrogen protection, the intermediate ZJ-1 (43.68g, 0.12mol, 1eq), phenylboronic acid SM-3 (14.64g, 0.12mol, 1eq) were added to the reaction flask, and 500ml of toluene, 120ml of ethanol, potassium carbonate (41.4g, 0.3mol, 2.5eq), and Pd(PPh3)4 (1.386g, 0.0012mol, 1%) were added. After the addition was completed, the reaction solution was heated and refluxed overnight, and the reaction was completed by HPLC sampling.

[0072] Post-treatment: After cooling, the reaction solution was washed with water, separated, and the organic phase was passed through silica gel, concentrated to dryness, and subjected to column chromatography to obtain approximately 33 g of product ZJ-2 with a yield of 41%.

[0073] Step S3:

[0074]

[0075] Process: Under nitrogen protection, the reaction flask was added with carbazole compound ZJ-2 (33g, 0.0914mol, 1eq), diboronic acid pinacol ester (29g, 0.114mol, 1.25eq), 1,4-dioxane 400ml, potassium acetate (22.4g, 0.2284mol, 2.5eq), Pd2(dba)3 (2.5g, 0.0027mol, 3%eq), X-phos (2.6g, 0.0054mol, 6%). After the addition was completed, the reaction solution was heated and refluxed overnight, and the reaction was completed by HPLC sampling.

[0076] Post-treatment: After cooling, the reaction solution was washed with water, separated, and the organic phase was passed through silica gel, concentrated to dryness, and subjected to column chromatography to obtain approximately 40 g of product ZJ-3 with a yield of 99%.

[0077] Step S4:

[0078]

[0079] Process: Under nitrogen protection, borate compound ZJ-3 (40g, 0.0914mol, 1eq), triazine compound SM-4 (32.6g, 0.914mol, 1eq) were added to the reaction flask, and 500ml of toluene, 120ml of ethanol, potassium carbonate (32.7g, 0.237mol, 2.5eq), and Pd(PPh3)4 (1.1g, 0.001mol, 1%) were added. After the addition was completed, the reaction solution was heated and refluxed to react overnight, and the reaction was completed by HPLC sampling.

[0080] Post-treatment: The reaction mixture was cooled and washed with water, separated, and the organic phase was filtered through silica gel, concentrated to dryness, and purified by column chromatography to obtain approximately 24 g of product 2, with a yield of 41%. Compounds 1, 3, 10, 11, 12, 13, 20, 21, 22, 31, 32, 41, 42, 51, 52, 61, 62, 71, 72, 81, 82, 91, 92, 101, 102, 111, 112, 121, 122, 131, 132, 141, 142, 151, 152, 161, 162, 171, 172, 181, 182, 191, 192, and 195 were obtained using a similar method. See Table 1 for details.

[0081] Table 1

[0082]

[0083]

[0084]

[0085]

[0086]

[0087]

[0088]

[0089]

[0090]

[0091]

[0092] The compounds prepared in Table 1 above were synthesized and identified, and the results are shown in Table 2 below:

[0093] Table 2

[0094]

[0095]

[0096]

[0097] The above materials were subjected to basic performance tests, including thermal weight loss temperature Td and glass transition temperature Tg. The test results are shown in Table 3 below.

[0098] Note: Thermal gravimetric loss temperature (Td) is the temperature at which the weight loss ratio is 5% in a nitrogen atmosphere, and is measured on a TGA N-1000 thermogravimetric analyzer with a nitrogen flow rate of 10 mL / min. Tg (glass transition temperature) is measured by differential scanning calorimetry (DSC, Xinke DSC N-650) with a heating rate of 10°C / min.

[0099] Table 3

[0100]

[0101]

[0102] According to the above data, the compounds synthesized in the present invention have excellent thermal stability, which means that the compounds conforming to the general structural formula of the present invention all have excellent thermal stability and can meet the requirements for use as organic electroluminescent materials.

[0103] Device performance test:

[0104] Application Example 1:

[0105] ITO was used as the reflective layer anode substrate material, and its surface was treated with water, acetone, and N2 in sequence;

[0106] On top of the ITO anode substrate, 10 nm of HT-1 containing 3 wt% NDP-9 was deposited to form a hole injection layer (HIL);

[0107] A 100 nm layer of HT-1 was evaporated on the hole injection layer (HIL) to form the first hole transport layer (HTL);

[0108] GP was vacuum evaporated on the first hole transport layer (HTL) to form a second hole transport layer (GPL) with a thickness of 30 nm;

[0109] Compound 2 and G1 designed by the present invention were co-evaporated at a mass ratio of 5:5 as green host materials, and GD-1 was evaporated as a doping material (the amount of GD-1 was 8% of the total mass of compound 2 and G1) on the second hole transport layer (GPL) to form a light-emitting layer with a thickness of 30 nm;

[0110] HB-1 was evaporated onto the light-emitting layer to obtain a hole blocking layer (HBL) with a thickness of 20 nm;

[0111] ET-1 and LiQ were co-evaporated onto the hole blocking layer (HBL) in a mass ratio of 5:5 to obtain an electron transport layer (ETL) with a thickness of 30 nm.

[0112] Magnesium (Mg) and silver (Ag) were mixed and evaporated on the electron transport layer (ETL) in a mass ratio of 9:1 to form an electron injection layer (EIL) with a thickness of 50 nm.

[0113] Silver (Ag) is then evaporated onto the electron injection layer to form a 100nm-thick cathode. A 50nm-thick layer of DNTPD is deposited on the cathode sealing layer. Furthermore, the cathode surface is sealed with a UV-curable adhesive and a sealcap containing a desiccant to protect the organic electroluminescent device from atmospheric oxygen or moisture. Thus, an organic electroluminescent device is prepared.

[0114]

[0115]

[0116] Application Example 2-45

[0117] Compounds 1, 3, 10, 11, 12, 13, 20, 21, 22, 31, 32, 41, 42, 51, 52, 61, 62, 71, 72, 81, 82, 91, 92, 101, 102, 111, 112, 121, 122, 131, 132, 141, 142, 151, 152, 161, 162, 171, 172, 181, 182, 191, 192, and 195 in Examples 2-36 of the present invention were respectively used as green light host materials for co-evaporation, and the other parts were consistent with those in Application Example 1, thereby producing the organic electroluminescent device of Application Example 2-45.

[0118] Comparative Examples 1-14:

[0119] The difference from Application Example 1 is that compounds 16, 33-35, 104, and 128 in CN113493446A, compounds 64 and 66 in US20180248127A1, H2-14 and H2-189 in CN113493446A, and D4-1, D4-2, D4-3, and D4-4 in CN116457351A are used as green light main materials for co-evaporation, and the rest is the same as Application Example 1.

[0120] The characteristics of the organic electroluminescent device manufactured in the above application example and the organic electroluminescent device manufactured in the comparative example were measured at a current density of 10 mA / cm 2 . The results are shown in Table 4 below.

[0121] Table 4

[0122]

[0123]

[0124]

[0125] As shown in Table 4 above, when the compounds of the present invention are applied to organic electroluminescent devices, at the same current density, the luminous efficiency is significantly improved, the starting voltage of the device is reduced, the power consumption of the device is relatively reduced, and the life of the device is correspondingly increased.

[0126] The organic electroluminescent devices prepared in Control Examples 1-14 and Application Examples 10, 12, 14, 16, 18, 20, 22, and 24 were tested for luminescence lifetime, and the luminescence lifetime T97% data (the time it takes for the luminescence brightness to drop to 97% of the initial brightness) were obtained. The test equipment was a TEO light-emitting device lifetime test system. The results are shown in Table 5:

[0127] Table 5:

[0128]

[0129]

[0130] As can be seen from Table 5 above, when the compound of the present invention is applied to an organic electroluminescent device, the service life is greatly improved at the same current density, and the compound has broad application prospects.

[0131] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. An organic electroluminescent compound having a triazine group, characterized in that: The organic electroluminescent compound with a triazine group is a compound with the following structural formula:

2. An organic electroluminescent device, characterized in that: The invention comprises a first electrode, a second electrode, and an organic layer formed between the first electrode and the second electrode, wherein the organic layer comprises a hole injection layer, a hole transport layer, a second hole transport layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer; and the light-emitting layer contains the following organic electroluminescent compound: The light-emitting layer further contains a compound of the following formula (7): wherein Y1 and Y2 are each independently a single bond, a substituted or unsubstituted C6 to C20 arylene group; Ar1 and Ar2 are each independently a substituted or unsubstituted C6 to C20 aryl group, a substituted or unsubstituted C2 to C24 heteroaryl group; Ar3 to Ar16 are each independently hydrogen, deuterium, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C6 to C20 aryl group, a substituted or unsubstituted C2 to C24 heteroaryl group, a cyano group, or a combination thereof, and the substituent is a C6 to C20 aryl group.

3. An organic electroluminescent device according to claim 2, characterized in that: The light-emitting layer contains a light-emitting host material, and the compound of formula (7) is as follows:

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