A dual-host material and an organic electroluminescent device comprising the same

Abstract

The application provides a double-host material and an organic electroluminescent device, and belongs to the technical field of organic photoelectric materials.The double-host material comprises a first host material and a second host material, the first host material has a structure represented by formula 1, and the second host material has a structure represented by formula 2.By compounding the first host compound and the second host compound with specific structures, as the light-emitting layer material of the organic electroluminescent device, the application can balance the hole and electron mobility, so that the double-host material increases excitons in the light-emitting layer, improves the luminous efficiency and service life of the device, and reduces the driving voltage.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of organic optoelectronic materials, and particularly relates to a dual-host material and an organic electroluminescent device comprising the same. BACKGROUND

[0002] At present, OLED (organic electroluminescent device) mainly uses phosphorescent material with excellent luminous efficiency in panel display. In many applications such as TV and lighting equipment, the OLED lifetime is insufficient, and high OLED efficiency is still needed. Typically, the higher the brightness of the OLED becomes, the shorter the lifetime of the OLED is accordingly. Therefore, for long-term use and high display resolution, OLEDs with high luminous efficiency and long lifetime characteristics are needed.

[0003] Various materials for the organic layer of the organic electroluminescent device have been proposed in order to improve the luminous efficiency, driving voltage and lifetime, but these are not satisfactory in actual use. In addition, there is a continuing need to develop organic electroluminescent devices with improved performance compared to the prior art disclosed organic electroluminescent devices, such as: improved driving voltage, luminous efficiency, power efficiency and lifetime characteristics. SUMMARY

[0004] In view of the deficiencies of the prior art, the purpose of the present application is to provide a dual-host material, an organic electroluminescent material and an organic electroluminescent device comprising the same.

[0005] To achieve the purpose of the present application, the following technical solutions are adopted:

[0006] In one aspect, the present application provides a dual-host material, which comprises a first host material and a second host material, the first host material has a structure represented by Formula 1, and the second host material has a structure represented by Formula 2:

[0007] ;

[0008] wherein L1 and L2 exist simultaneously, and are selected from one or a combination of at least two of any of the following structures:

[0009]

[0010] Ar1, Ar2and R groups are independently selected from the group consisting of: -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, -SiMe3, -GeMe3, substituted or unsubstituted C2-C18alkyl, substituted or unsubstituted C3-C18cycloalkyl, substituted or unsubstituted C6-C30aryl, and substituted or unsubstituted C6-C30heteroaryl, or a combination of at least two thereof, and the asterisk represents the point of attachment of the group;

[0011] H in the above Formula 1 is unsubstituted by deuterium, partially substituted by deuterium, or fully substituted by deuterium.

[0012] L3and L4are present simultaneously and are selected from any one of the following structures or a combination of at least two thereof:

[0013]

[0014] Ar3, Ar4and R' groups are independently selected from the group consisting of: -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, -SiMe3, -GeMe3, substituted or unsubstituted C2-C18alkyl, substituted or unsubstituted C3-C18cycloalkyl, substituted or unsubstituted C6-C30aryl, or substituted or unsubstituted C6-C30heteroaryl, or a combination of at least two thereof, and the asterisk represents the point of attachment of the group;

[0015] H in the above Formula 2 is unsubstituted by deuterium, partially substituted by deuterium, or fully substituted by deuterium.

[0016] In the present application, the C2-C18may be C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, or C18, etc., the C3-C18may be C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, or C18, etc., and the C6-C30may be C6, C7.5, C9, C10, C12, C14, C15, C16, C18, C19, C21, C22, C24, C26, C28, or C30, etc.

[0017] Further, Ar1, Ar2and R groups are independently selected from the group consisting of methyl, tert-butyl, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted anthryl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted 9-phenyl-9H-carbazolyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted dimethylfluorenyl, substituted or unsubstituted phenanthrofuranyl, substituted or unsubstituted phenanthrothiophenyl, substituted or unsubstituted naphthobenzofuranyl.

[0018] wherein the above "substitution" is selected from the group consisting of deuterium, fluorine, cyano, methyl, trifluoromethyl, tert-butyl, C6-C24 aryl, C6-C24 heteroaryl, wherein the heteroatoms are selected from O, S or N.

[0019] In the above technical solution, the first host material is the following compound, but is not limited to the following compound:

[0020]

[0021] wherein "Dn" in the above compound means n number of hydrogens are replaced by deuterium, wherein n represents an integer of 1 or more and the upper limit of n is determined by the number of hydrogens that can be replaced in each compound, i.e. n represents an integer between 1 and the maximum number of substitutions, for example 1, 2, 3, 4, 5, 6, 7, 8, 9, 10... to the maximum number of substitutions.

[0022] Further, Ar3, Ar4and R' groups are independently selected from the group consisting of methyl, tert-butyl, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted anthryl, substituted or unsubstituted biphenylyl, substituted or unsubstituted terphenylyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted 9-phenyl-9H-carbazolyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted dimethylfluorenyl, substituted or unsubstituted phenanthrofuranyl, substituted or unsubstituted phenanthrothiophenyl, substituted or unsubstituted naphthobenzofuranyl.

[0023] wherein the above "substitution" is selected from the group consisting of deuterium, fluorine, cyano, methyl, trifluoromethyl, tert-butyl, C6-C24 aryl, C6-C24 heteroaryl, wherein the heteroatoms are selected from O, S, N.

[0024] In the above technical solution, the second host material is the following compound, but is not limited to the following compound:

[0025]

[0026]

[0027] ;

[0028] wherein "Dn" in the above compounds means that n number of hydrogens are replaced by deuterium, wherein n represents an integer of 1 or more and the upper limit of n is determined by the number of hydrogens that can be replaced in each compound, i.e. n represents an integer between 1 and the maximum number of substitutions, for example 1, 2, 3, 4, 5, 6, 7, 8, 9, 10... to the maximum number of substitutions.

[0029] Preferably, the mass ratio of the first host material and the second host material in the dual-host material is (10~90):(90~10), for example, 10:90, 15:85, 20:80, 25:75, 30:70, 35:65, 40:60, 45:55, 50:50, 60:40, 70:30, 80:20, or 90:10, preferably 60~40:40~60.

[0030] The compound represented by Formula 1 or Formula 2 of the present application can be manufactured by referring to the synthetic method known to those skilled in the art. In addition, the deuterated compound of Formula 1 and Formula 2 can be prepared in a similar manner using deuterated precursor materials, which can generally be prepared by treating a non-deuterium-bearing compound with a deuterated solvent, benzene-D6, in the presence of a Lewis acid H / D exchange catalyst such as aluminum trichloride or trifluoromethanesulfonic acid. In addition, the degree of deuteration can be controlled by changing the reaction conditions such as the reaction temperature. For example, the number of deuterations in Formula 1 and 2 can be adjusted by controlling the reaction temperature and time, acid equivalents, etc.

[0031] In another aspect, the present application provides an organic electroluminescent device including a first electrode; a second electrode; and at least one organic layer interposed between the first electrode and the second electrode, the organic layer including an emission layer, the emission layer including the dual-host material as described above.

[0032] The dual-host material of the present application includes at least one compound among the compounds H1-1 to H1-650 as a first host compound and at least one compound among the compounds H2-1 to H2-600 as a second host compound. The dual-host material can be contained in the same organic layer, for example, the same emission layer, or can be contained in different emission layers.

[0033] In addition to the emission layer, the organic layer can further include at least one layer selected from the group consisting of a hole injection layer, a hole transport layer, a hole auxiliary layer, an emission auxiliary layer, an electron transport layer, an electron injection layer, an intermediate layer, a hole blocking layer, an electron blocking

[0034] layer, and an electron buffer layer.

[0035] In addition to the light-emitting material of the present application, the organic layer can further include an amine-based compound or an azine-based compound.

[0036] Specifically, the hole injection layer, the hole transport layer, the hole auxiliary layer, the emission layer, the emission auxiliary layer, the electron blocking layer, etc. can contain an amine-based compound (for example, an arylamine-based compound and a styryl arylamine-based compound, etc.).

[0037] The organic electroluminescent device of the present application can further comprise at least one dopant in the light-emitting layer. Preferably, the dopant can be at least one phosphorescent dopant or fluorescent dopant, preferably fluorescent dopant.

[0038] In the present application, the preparation method of the light-emitting layer includes, but is not limited to, forming the organic electroluminescent material into a light-emitting layer by a solution coating method and a vacuum deposition method; the solution coating method means spin coating, dip coating, inkjet printing, screen printing, spraying method, etc., but is not limited thereto.

[0039] In the present application, the organic electroluminescent device can be a top emission type, a bottom emission type or a double-sided emission type.

[0040] Compared with the prior art, the present application has the following beneficial effects:

[0041] The present application provides a first host material and a second host material with a specific structure, which combines two different characteristic hosts. By compounding the first host compound and the second host compound with a specific structure, as a light-emitting layer material of an organic electroluminescent device, the specific structure of the double host material can balance the hole and electron mobility, increase the exciton in the light-emitting layer, improve the luminous efficiency and service life of the device, and reduce the driving voltage. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 NMR chart of the first host compound H1-222 prepared in Example 1. DETAILED DESCRIPTION

[0043] The technical solutions of the present application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only to help understand the present application, and should not be regarded as specific limitations of the present application.

[0044] It should be noted that the numerical values given in the following examples are as accurate as possible, but those skilled in the art understand that due to unavoidable measurement errors and experimental operation problems, each number should be understood as an approximate number, not an absolutely accurate number.

[0045] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available.

[0046] Reference is made to the following well-known knowledge:

[0047] 1. Basic Organic Chemistry (3rd Edition, Volume 1), Xing Qiyi, Pei Weiwei, Xu Ruiqiu, Pei Jian, Publisher: Higher Education Press, Publication Time: 2005.06, ISBN: 978-7-04-016637-8, pp. 472-473.

[0048] 2. Peng, Design, Synthesis of Phenyl Bridged Di-anthracene Organic Deep Blue Light-emitting Materials and Their Applications in Organic Electroluminescent Devices[D]. South China University of Technology, 2019, 36-38.

[0049] Example 1: Preparation of compound H1-222

[0050] The raw material A-222 (1.0 eq, CAS: 2883453-97-0), raw material B-222 (1.0 eq, CAS: 2261008-20-0) and potassium carbonate (3.0 eq) were added to the reaction bottle, followed by adding a mixed solution of toluene, ethanol and water (V:V:V = 3:1:1), and then adding tetrakis(triphenylphosphine)palladium (0.03 eq) under nitrogen protection, heating to 90°C and refluxing for 5 h. The reaction was detected by thin layer chromatography. After the reaction was completed, the temperature was slightly lowered, and diatomite was used for filtration to remove the salt and catalyst. After the filtrate was cooled to room temperature, dichloromethane and water were added for extraction and separation, and the organic phase was concentrated. The product H1-222 was obtained by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:4) (yield 63.50%, HPLC > 99%, mass spectrometry test value 520.38, elemental analysis test value C: 92.22; H: 4.70; N: 3.08). The reaction route is shown below.

[0051] The nuclear magnetic resonance hydrogen spectrum of H1-222 is shown in Figure 1 .

[0052] .

[0053] Example 2: Preparation of compound H1-497

[0054] Under a nitrogen atmosphere, 1 eq of compound H1-222 and solvent o-dichlorobenzene were added to a three-necked flask, and after complete dissolution at room temperature with stirring, 50 eq of benzene-d6 was added, and stirred at 10°C for 5 min. Then, 2 eq of trifluoromethanesulfonic acid was added, and stirred at 10°C for 2 h. Then, heavy water was added, and further stirred for 20 min. After stirring, the water layer was removed and the remaining organic layer was concentrated. The obtained solid was refined by silica gel chromatography to obtain the product H1-497 (yield 62.3%, HPLC > 99%, mass spectrometry test value 535.41, elemental analysis test value C: 89.54; H: 7.45; N: 3.01). The reaction route is shown below.

[0055] .

[0056] The synthesis methods of other compounds are similar or the same as the above examples, which are not described here.

[0057] Device Embodiment: Preparation of Organic Electroluminescent Device

[0058] The structure of the prepared OLED device is: ITO anode / HIL / HTL / Prime / EML / HBL / ETL / EIL / cathode / CPL.

[0059] a, ITO anode: ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate with a coating thickness of 1500 angstroms

[0060] Washing 2 times in distilled water, ultrasonic washing for 30 min, and then washing 2 times in distilled water, ultrasonic washing for 10 min, and then washing in methanol, acetone, and isopropanol in sequence (5 min for each washing), drying, and then transferring to a plasma cleaning machine for washing for 5 min, and then sending to an evaporation machine, and then evaporating other functional layers on the substrate as an anode.

[0061] b, HIL (hole injection layer): evaporating hole injection layer materials HT and P-dopant at an evaporation rate of 1 angstrom / second, the evaporation rate ratio of the HT and P-dopant being 97:3, and the thickness being 10 nm.

[0062] c, HTL (hole transport layer): evaporating 130 nm of HT as a hole transport layer on the hole injection layer at an evaporation rate of 1.5 angstrom / second.

[0063]

[0064] d, Prime (light-emitting auxiliary layer): evaporating 5 nm of Prime as a light-emitting auxiliary layer on the hole transport layer at an evaporation rate of 0.5 angstrom / second.

[0065]

[0066] e, EML (light-emitting layer): performing linear gradient co-evaporation by using a multi-source co-evaporation method, and obtaining a light-emitting layer with a thickness of 30 nm; the light-emitting layer comprises a double-host material and a doping material, the mass ratio of the first host compound and the second host compound is 50:50, and the doping material accounts for 2wt% of the total mass of the double-host material and the doping material, and the double-host material is the host material provided in embodiments 1-40 and comparative examples 1-10.

[0067] f, HBL (hole blocking layer): evaporating a hole blocking layer HB with a thickness of 5 nm at an evaporation rate of 0.5 angstrom / second.

[0068] g, ETL (electron transport layer): evaporating ET and Liq as an electron transport layer with a thickness of 30 nm at an evaporation rate of 1 angstrom / second.

[0069] ​​An electron transport layer. The evaporation rate ratio of ET and Liq is 50:50.

[0070] h. An EIL (electron injection layer): Yb film layer 1 nm was evaporated at an evaporation rate of 0.5 angstroms / second to form an electron injection layer.

[0071] i. A cathode: Magnesium and silver 13 nm were evaporated at an evaporation rate ratio of 1:9 at an evaporation rate of 1 angstrom / second.

[0072] j. A CPL (cover layer): A CPL with a thickness of 65 nm was vacuum evaporated on the cathode as a cover layer at an evaporation rate of 1 angstrom / second.

[0073] k. The substrate on which evaporation was completed was then encapsulated. First, the cleaned cover plate was coated with UV glue using a gluing device, then the coated cover plate was moved to the pressing section, the substrate on which evaporation was completed was placed on the end of the cover plate, and finally the substrate and the cover plate were bonded under the action of the bonding device, and the UV glue was cured by light at the same time.

[0074] The structural formulas of HT, P-dopant, Prime, Dopant, HB, ET, and CPL used in the above device embodiments are as follows:

[0075]

[0076] According to the method provided in the above device embodiments, the corresponding double-host materials in Table 1 were selected to evaporate the light-emitting layer host materials, and the corresponding organic electroluminescence devices were prepared, which are respectively denoted as device comparative examples 1-10 and device embodiments 1-40. The formula of the host material is shown in Table 1. For the scheme in which the double-host material includes a first host compound and a second host compound: the mass ratio of the first host compound to the second host compound is 50:50. In Table 1, “-” indicates that there is no compound in the host material.

[0077] The driving voltage, luminous efficiency of the organic electroluminescence device at a brightness of 1000 nits, and the time (lifetime; T95) taken for the brightness to decrease from 100% to 95% at a brightness of 1000 nits were tested, and the test results are shown in Table 1.

[0078] Table 1

[0079]

[0080]

[0081] As shown in Table 1, it can be confirmed that the organic electroluminescent device comprising the dual-host material of the present application exhibits lower driving voltage and higher luminous efficiency and longer lifespan, etc. characteristics than the organic electroluminescent device comprising only a single host material.

[0082] The applicant declares that the dual-host material and the organic electroluminescent device of the present application are illustrated by the above examples, but the present application is not limited to the above examples, i.e., it does not mean that the present application must be implemented depending on the above examples. It should be understood by those skilled in the art that any improvement on the present application, equivalent replacement of the raw materials selected by the present application, addition of auxiliary ingredients, selection of specific modes, etc. fall within the scope of protection and disclosure of the present application.

Claims

1. A dual-body material, characterized in that, The dual-body material includes a first body material and a second body material. The first body material has a structure represented by Formula 1, and the second body material has a structure represented by Formula 2. ； Where L1 and L2 exist simultaneously, and are selected from any one or at least a combination of the following structures: ； Ar1, Ar2, and R groups are selected from unsubstituted to the most substituted group in their respective rings, and are selected from: -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, -SiMe3, -GeMe3, unsubstituted C2-C18 alkyl, unsubstituted C3-C18 cycloalkyl, unsubstituted C6-C30 aryl and unsubstituted C6-C30 heteroaryl, or a combination thereof. The asterisk represents the linking site of the group. In Equation 1 above, H represents the element that is not deuterated, partially deuterated, or completely deuterated; L3 and L4 are both present, and are selected from any one or at least a combination of the following structures: ； Ar3, Ar4 and R' groups are independently selected from unsubstituted to the most substituted group in the ring, selected from: -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, -SiMe3, -GeMe3, unsubstituted C2-C18 alkyl, unsubstituted C3-C18 cycloalkyl, unsubstituted C6-C30 aryl or unsubstituted C6-C30 heteroaryl, or one or a combination of at least two of them. The asterisk represents the linking site of the group. In Equation 2 above, H represents substances that are not deuterated, partially deuterated, or completely deuterated.

2. The dual-body material according to claim 1, characterized in that, Ar1, Ar2 and R group are independently selected from methyl, tert-butyl, unsubstituted phenyl, unsubstituted naphthyl, unsubstituted phenanthryl, unsubstituted anthracene, unsubstituted biphenyl, unsubstituted terphenyl, unsubstituted dibenzofuranyl, unsubstituted 9-phenyl-9H-carbazolyl, unsubstituted dibenzothiophene, unsubstituted dimethylfluorenyl, unsubstituted phenanthrene, unsubstituted phenanthrene, and unsubstituted naphthobenzofuranyl.

3. A dual-body material, characterized in that, The first host material is any one of the following compounds: ； Where Dn means that n numbers of hydrogen atoms are replaced by deuterium, and n represents an integer between 1 and the maximum number of substitutions; The second main material has the structure represented by Equation 2: ； L3 and L4 are both present, and are selected from any one or at least a combination of the following structures: ； Ar3, Ar4 and R' groups are independently selected from unsubstituted to the most substituted group in the ring, selected from: -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, -SiMe3, -GeMe3, unsubstituted C2-C18 alkyl, unsubstituted C3-C18 cycloalkyl, unsubstituted C6-C30 aryl or unsubstituted C6-C30 heteroaryl, or one or a combination of at least two of them. The asterisk represents the linking site of the group. In Equation 2 above, H represents substances that are not deuterated, partially deuterated, or completely deuterated.

4. The dual-body material according to claim 1 or 3, characterized in that, Ar3, Ar4, and R' groups are independently selected from methyl, tert-butyl, unsubstituted phenyl, unsubstituted naphthyl, unsubstituted phenanthryl, unsubstituted anthracene, unsubstituted biphenyl, unsubstituted terphenyl, unsubstituted dibenzofuranyl, unsubstituted 9-phenyl-9H-carbazolyl, unsubstituted dibenzothiophene, unsubstituted dimethylfluorenyl, unsubstituted phenanthrene, unsubstituted phenanthrene, and unsubstituted naphthobenzofuranyl.

5. The dual-body material according to claim 1 or 3, characterized in that, The second host material is any one of the following compounds: ； Where Dn means that n numbers of hydrogen atoms are replaced by deuterium, and n represents an integer between 1 and the maximum number of substitutions.

6. The dual-body material according to claim 1 or 3, characterized in that, The mass ratio of the first main material and the second main material in the dual main material is (10~90):(90~10).

7. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes a first electrode; a second electrode; and at least one organic layer inserted between the first electrode and the second electrode, the organic layer including a light-emitting layer, the light-emitting layer comprising the dual-body material of any one of claims 1-6.

8. The organic electroluminescent device according to claim 7, characterized in that, The organic layer further comprises any one or a combination of at least two of the following: a hole injection layer, a hole transport layer, a hole auxiliary layer, a light emission auxiliary layer, an electron transport layer, an electron injection layer, a hole blocking layer, an electron blocking layer, or an electron buffer layer.

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