Double-host material and organic electroluminescent device comprising same

Abstract

The invention provides a dual-host material and an organic electroluminescent device, and belongs to the technical field of organic photoelectric materials, the dual-host material comprises a first host material and a second host material, the first host material has a structure represented by a formula 1, and the second host material has a structure represented by a formula 2. The first host compound and the second host compound with specific structures are compounded to serve as a luminescent layer material of the organic electroluminescent device, hole and electron mobility can be balanced, so that the dual-host material increases excitons in the luminescent layer, the luminescent efficiency of the device is improved, the service life of the device is prolonged, and the driving voltage is reduced.

Description

Technical Field

[0001] This invention belongs to the field of organic optoelectronic materials technology, specifically relating to a dual-host material and an organic electroluminescent device containing the same. Background Technology

[0002] Currently, OLEDs (Organic Light Emitting Diodes) primarily utilize phosphorescent materials with excellent luminous efficiency in panel displays. However, in many applications such as TVs and lighting equipment, OLED lifetime is insufficient, and high OLED efficiency remains a requirement. Typically, the higher the brightness of an OLED, the shorter its lifetime. Therefore, for long-term use and high display resolution, OLEDs with both high luminous efficiency and long lifetime are needed.

[0003] Various materials for organic layers in organic light-emitting devices (OLEDs) have been proposed to improve luminous efficiency, driving voltage, and lifetime, but these have not been satisfactory in practical applications. Furthermore, there is a need to continue developing OLEDs with improved performance characteristics, such as improved driving voltage, luminous efficiency, power efficiency, and lifetime, compared to existing OLEDs. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a dual-body material, an organic electroluminescent material, and an organic electroluminescent device comprising the same.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] On one hand, the present invention provides a dual-body material, the dual-body material comprising a first body material and a second body material, wherein the first body material has a structure represented by Formula 1, and the second body material has a structure represented by Formula 2:

[0007] ;

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

[0009]

[0010] Ar1, Ar2, and R groups are selected from unsubstituted to the most substituted group in their respective rings, selected from: -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, -SiMe3, -GeMe3, substituted or unsubstituted C2-C18 alkyl, substituted or unsubstituted C3-C18 cycloalkyl, substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C6-C30 heteroaryl, or combinations thereof. The asterisk represents the linking site of the group.

[0011] In Equation 1 above, H represents the element that is not deuterated, partially deuterated, or completely deuterated;

[0012] L3 and L4 are both present, and are selected from any one or at least a combination of the following structures:

[0013]

[0014] 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, substituted or unsubstituted C2-C18 alkyl, substituted or unsubstituted C3-C18 cycloalkyl, substituted or unsubstituted C6-C30 aryl or substituted or unsubstituted C6-C30 heteroaryl, one or a combination of at least two of them, with the asterisk representing the linking site of the group;

[0015] In Equation 2 above, H represents substances that are not deuterated, partially deuterated, or completely deuterated.

[0016] In this invention, C2-C18 can be C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, or C18, etc.; C3-C18 can be C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, or C18, etc.; and C6-C30 can be C6, C7.5, C9, C10, C12, C14, C15, C16, C18, C19, C21, C22, C24, C26, C28, or C30, etc.

[0017] Furthermore, Ar1, Ar2, and R groups are independently selected from methyl, tert-butyl, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted anthrayl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted 9-phenyl-9H-carbazolyl, substituted or unsubstituted dibenzothiophene, substituted or unsubstituted dimethylfluorenyl, substituted or unsubstituted phenanthrene, substituted or unsubstituted phenanthrene, and substituted or unsubstituted naphthobenzofuranyl.

[0018] The above-mentioned "substitution" is selected from deuterium, fluorine, cyano, methyl, trifluoromethyl, tert-butyl, C6-C24 aryl, and C6-C24 heteroaryl, wherein the heteroatom is selected from O, S or N.

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

[0020]

[0021] In the above compounds, "Dn" means that n numbers of hydrogens are replaced by deuterium, where n represents an integer of 1 or greater and the upper limit of n is determined by the number of hydrogens that can be substituted in each compound. That is, n represents an integer between 1 and the maximum number of substitutions, such as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10... up to the maximum number of substitutions.

[0022] Furthermore, Ar3, Ar4, and R' groups are independently selected from methyl, tert-butyl, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted anthrayl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted 9-phenyl-9H-carbazolyl, substituted or unsubstituted dibenzothiophene, substituted or unsubstituted dimethylfluorenyl, substituted or unsubstituted phenanthrene, substituted or unsubstituted phenanthrene, and substituted or unsubstituted naphthobenzofuranyl.

[0023] The above-mentioned "substitution" is selected from deuterium, fluorine, cyano, methyl, trifluoromethyl, tert-butyl, C6-C24 aryl, and C6-C24 heteroaryl, wherein the heteroatom is selected from O, S, and N.

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

[0025]

[0026]

[0027] ;

[0028] In the above compounds, "Dn" means that n numbers of hydrogens are replaced by deuterium, where n represents an integer of 1 or greater and the upper limit of n is determined by the number of hydrogens that can be substituted in each compound. That is, n represents an integer between 1 and the maximum number of substitutions, such as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10... up to the maximum number of substitutions.

[0029] Preferably, the mass ratio of the first main material and the second main material in the dual main 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 compounds represented by Formula 1 or Formula 2 of this invention can be manufactured by synthetic methods known to those skilled in the art. Furthermore, the deuterated compounds of Formula 1 and Formula 2 can be prepared in a similar manner using deuterated precursor materials, typically by treating non-deuterated compounds with the deuterated solvent benzene-D6 in the presence of a Lewis acid H / D exchange catalyst (such as aluminum trichloride or trifluoromethanesulfonic acid). Moreover, the degree of deuteration can be controlled by changing the reaction conditions (such as reaction temperature). For example, the number of deuterated compounds in Formulas 1 and 2 can be adjusted by controlling the reaction temperature and time, acid equivalent, etc.

[0031] On the other hand, the present invention provides an organic electroluminescent device, the organic electroluminescent device comprising a first electrode; a second electrode; and at least one organic layer inserted between the first electrode and the second electrode, the organic layer comprising a light-emitting layer comprising the dual-body material as described above.

[0032] The dual-body material of the present invention comprises at least one compound selected from compounds H1-1 to H1-650 as a first body compound and at least one compound selected from compounds H2-1 to H2-600 as a second body compound. The dual-body material may be contained in the same organic layer, for example, the same luminescent layer, or it may be contained in different luminescent layers.

[0033] In addition to the light-emitting layer, the organic layer may further comprise at least one layer selected from the following: a hole injection layer, a hole transport layer, a hole auxiliary layer, a light-emitting auxiliary layer, an electron transport layer, an electron injection layer, an intermediate layer, a hole blocking layer, and an electron blocking layer.

[0034] Barrier layer and electronic buffer layer.

[0035] In addition to the luminescent material of the present invention, the organic layer may further comprise amine-based compounds or azazine-based compounds.

[0036] Specifically, the hole injection layer, hole transport layer, hole auxiliary layer, light-emitting layer, light-emitting auxiliary layer, electron blocking layer, etc., may contain amine-based compounds (e.g., arylamine-based compounds and styrylarylamine-based compounds, etc.).

[0037] The organic electroluminescent device of the present invention may further include at least one dopant in the light-emitting layer. Preferably, the dopant may be at least one phosphorescent dopant or a fluorescent dopant, with a fluorescent dopant being preferred.

[0038] In this invention, the method for preparing the light-emitting layer includes, but is not limited to, forming the light-emitting layer from the organic electroluminescent material by solution coating and vacuum deposition; the solution coating method refers to spin coating, dip coating, inkjet printing, screen printing, spraying, etc., but is not limited to these.

[0039] In this invention, the organic electroluminescent device can be a top-emitting type, a bottom-emitting type, or a dual-sided emitting type.

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

[0041] This invention provides a first host material and a second host material with a specific structure. The dual host material with the specific structure combines two host materials with different properties. By compounding the first host compound and the second host compound with the specific structure, it can be used as the light-emitting layer material of an organic electroluminescent device. It can balance the hole and electron mobility. By adding excitons in the light-emitting layer, the dual host material not only improves the luminous efficiency and lifespan of the device, but also reduces the driving voltage. Attached Figure Description

[0042] Figure 1 The image shows the nuclear magnetic resonance (NMR) spectrum of the first host compound H1-222 prepared in Example 1. Detailed Implementation

[0043] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0044] It should be noted that the values ​​given in the following embodiments are as accurate as possible. However, those skilled in the art will understand that due to unavoidable measurement errors and experimental operation issues, each number should be understood as an approximation rather than an absolutely accurate value.

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

[0046] The following are common knowledge references:

[0047] 1. Basic Organic Chemistry (3rd Edition, Volume 1), Xing Qiyi, Pei Weiwei, Xu Ruiqiu, Pei Jian, Publisher: Higher Education Press, Publication Date: June 2005, ISBN: 978-7-04-016637-8, Pages 472-473.

[0048] 2. Peng Ling, Design, Synthesis and Application of Phenyl-bridged Dianthrayl Organic Deep Blue Light-Emitting Material in Organic Electroluminescent Devices [D]. South China University of Technology, 2019, 36-38.

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

[0050] 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 a reaction flask, followed by the addition of a mixed solution of toluene, ethanol, and water (V:V:V). The reaction mixture was prepared by adding tetra(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 lowered slightly, and the mixture was filtered with diatomaceous earth to remove salt and catalyst. The filtrate was cooled to room temperature, extracted with dichloromethane and water, separated, and the organic phase was retained and concentrated. The product H1-222 was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:4) (yield 63.50%, HPLC>99%, mass spectrometry value 520.38, elemental analysis values ​​C: 92.22; H: 4.70; N: 3.08). The reaction route is shown below.

[0051] The proton NMR spectrum of H1-222 is shown below. Figure 1 .

[0052] .

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

[0054] Under a nitrogen atmosphere, 1 eq of compound H1-222 and the solvent o-dichlorobenzene were added to a three-necked flask and stirred at room temperature until completely dissolved. Then, 50 eq of benzene-d6 were added, and the mixture was stirred at 10°C for 5 minutes. Next, 2 eq of trifluoromethanesulfonic acid were added, and the mixture was stirred at 10°C for 2 hours. Then, heavy water was added, and the mixture was stirred for another 20 minutes. After stirring, the aqueous layer was removed, and the remaining organic layer was concentrated. The resulting solid was purified by silica gel chromatography to obtain product H1-497 (yield 62.3%, HPLC > 99%, mass spectrometry value 535.41, elemental analysis values ​​C: 89.54; H: 7.45; N: 3.01). The reaction route is shown below.

[0055] .

[0056] The synthesis methods for other compounds are similar to or the same as those in the above examples, and will not be described in detail here.

[0057] Device Examples: Fabrication of Organic Electroluminescent Devices

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

[0059] a. ITO anode: A glass substrate coated with ITO (Indium Tin Oxide)-Ag-ITO (Indium Tin Oxide) with a thickness of 1500 angstroms.

[0060] The substrate is washed twice with distilled water, ultrasonically cleaned for 30 minutes, then washed twice more with distilled water, ultrasonically cleaned for 10 minutes. After cleaning, it is ultrasonically cleaned sequentially with methanol, acetone, and isopropanol (5 minutes each time), dried, and then transferred to a plasma cleaner for 5 minutes. It is then sent to an evaporation machine, where other functional layers are sequentially deposited on the substrate using it as the anode.

[0061] b. HIL (Hole Injection Layer): Hole injection layer materials HT and P-dopant are vacuum-deposited at a deposition rate of 1 Å / s, wherein the deposition rate ratio of HT to P-dopant is 97:3, and the thickness is 10 nm.

[0062] c. HTL (Hole Transport Layer): A 130nm layer is vacuum-deposited on the hole injection layer at a deposition rate of 1.5 Å / s.

[0063] HT is used as the hole transport layer.

[0064] d. Prime (light-emitting auxiliary layer): 5nm of the hole transport layer was vacuum-deposited on top of the hole transport layer at a deposition rate of 0.5 Å / s.

[0065] Prime is used as a light-emitting auxiliary layer.

[0066] e. EML (Emitting Layer): A linear gradient co-evaporation method is used to obtain an emitting layer with a thickness of 30 nm. The material of the emitting layer includes a dual host material and a dopant material. The mass ratio of the first host compound and the second host compound is 50:50. The dopant material accounts for 2 wt% of the total mass of the dual host material and the dopant material. The dual host materials are the host materials provided in Examples 1-40 and Comparative Examples 1-10, respectively.

[0067] f. HBL (Hole Blocking Layer): A hole blocking layer HB with a thickness of 5 nm is vacuum-deposited at a deposition rate of 0.5 Å / s.

[0068] g. ETL (Electron Transport Layer): ET and Liq layers with a thickness of 30 nm were vacuum-deposited at a deposition rate of 1 Å / s.

[0069] Electron transport layer. The evaporation rate ratio of ET to Liq is 50:50.

[0070] h. EIL (Electron Injection Layer): A 1 nm Yb film is deposited at a deposition rate of 0.5 Å / s to form an electron injection layer.

[0071] i. Cathode: Magnesium and silver are deposited at a deposition rate of 1 Å / s, with a deposition rate ratio of 1:9.

[0072] j. CPL (Covering Layer): A 65 nm thick CPL is vacuum-deposited on the cathode at a deposition rate of 1 Å / s as a covering layer.

[0073] k. Subsequently, the vapor-deposited substrate is encapsulated. First, the cleaned cover plate is coated with UV adhesive using an adhesive coating equipment. Then, the coated cover plate is moved to the lamination section, and the vapor-deposited substrate is placed on the top of the cover plate. Finally, the substrate and cover plate are laminated under the action of the lamination equipment, while the UV adhesive is cured by light.

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

[0075]

[0076] Referring to the methods provided in the above device embodiments, the corresponding dual-host materials in Table 1 were selected for vapor deposition of the light-emitting layer host material, and corresponding organic electroluminescent devices were prepared, denoted as Device Comparative Examples 1-10 and Device Examples 1-40, respectively. The formulations of the host materials are shown in Table 1, wherein, for the dual-host material scheme including a first host compound and a second host compound, the mass ratio of the first host compound and the second host compound is 50:50. In Table 1, "-" indicates that the host material does not contain that compound.

[0077] The driving voltage, luminous efficiency, and time (lifetime; T95) of the organic electroluminescent device at a brightness of 1000 nits were tested. The test results are shown in Table 1.

[0078] Table 1

[0079]

[0080]

[0081] As shown in Table 1, it can be confirmed that organic electroluminescent devices containing the dual host materials of the present invention exhibit features such as lower driving voltage, higher luminous efficiency, and longer lifetime compared to organic electroluminescent devices containing only a single host material.

[0082] The applicant declares that the present invention is illustrated by the above embodiments to demonstrate the dual-substrate material and organic electroluminescent device of the present invention, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A dual host material, characterized by, The dual 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: ； wherein L1, L2 exist simultaneously, and are selected from one or a combination of at least two of any of the following structures: ； Ar1, Ar2 and R groups are independently selected from one or a combination of at least two of the following: -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, -SiMe3, -GeMe3, substituted or unsubstituted C2-C18 alkyl, substituted or unsubstituted C3-C18 cycloalkyl, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C6-C30 heteroaryl, and the asterisk represents the connecting site of the group; H in the above Formula 1 is unsubstituted by deuterium, partially substituted by deuterium, or fully substituted by deuterium; L3, L4 exist simultaneously, and are selected from one or a combination of at least two of any of the following structures: ； Ar3, Ar4 and R' groups are independently selected from one or a combination of at least two of the following: -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, -SiMe3, -GeMe3, substituted or unsubstituted C2-C18 alkyl, substituted or unsubstituted C3-C18 cycloalkyl, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C6-C30 heteroaryl, and the asterisk represents the connecting site of the group; H in the above Formula 2 is unsubstituted by deuterium, partially substituted by deuterium, or fully substituted by deuterium.

2. The dual host material of claim 1, wherein, Ar1, Ar2 and R groups are independently selected from 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.

3. The dual host material of claim 1, wherein, The first host material is any one of the following compounds: ； wherein Dn means that n number of hydrogens are replaced by deuterium, wherein n represents an integer between 1 and the maximum number of substitutions.

4. The dual host material of claim 1, wherein, Ar3, Ar4 and R' groups are independently selected from 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.

5. The dual host material according to claim 1 or 2 or 4, wherein, The substituents in the substituted groups are 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 the group consisting of O, S, N.

6. The dual host material of claim 1, wherein, The second host material is any one of the following compounds: ； wherein Dn means n number of hydrogens are replaced by deuterium, wherein n represents an integer between 1 and the maximum number of substitutions.

7. The dual host material of claim 1, wherein, The mass ratio of the first host material and the second host material in the double host material is (10-90):(90-10).

8. An organic electroluminescent device, characterized by The organic electroluminescence device comprises a first electrode; a second electrode; and at least one organic layer interposed between the first electrode and the second electrode, the organic layer comprising an emission layer, the emission layer comprising the double host material according to any one of claims 1-7.

9. The organic electroluminescent device according to claim 8, characterized in that The organic layer further comprises any one or a combination of at least two 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 layer, or an electron buffer layer.

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