An organic compound, its preparation method, and an organic electroluminescent device
By using fluorene compounds as the light-emitting auxiliary layer material in organic electroluminescent devices, the carrier balance is optimized, solving the problems of insufficient material stability and efficiency in the prior art, and realizing organic electrical components with low driving voltage and high luminous efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JILIN OPTICAL & ELECTRONICS MATERIALS CO LTD
- Filing Date
- 2026-04-27
- Publication Date
- 2026-05-26
AI Technical Summary
In the existing technology, how to develop stable and efficient organic layer materials for organic electrical components, especially to improve luminous efficiency and device lifespan under low operating voltage conditions, remains a challenge.
Using fluorene compounds with specific structures as light-emitting auxiliary layer materials, organic compounds I-1 and I-2 were prepared through a synthetic route and applied to the multilayer structure of organic electroluminescent devices, including hole injection layer, hole transport layer, and light-emitting layer, to optimize carrier balance and electron blocking capability.
It effectively reduces the driving voltage of organic electroluminescent devices, improves hole transport rate and electron blocking ability, increases charge balance, extends device life and improves luminous efficiency.
Smart Images
Figure CN122079795A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of luminescent materials technology, and more specifically to an organic compound, its preparation method, and an organic electroluminescent device. Background Technology
[0002] Organic light-emitting displays (OLEDs) are active-matrix display devices that feature self-illumination, vibrant and bright colors, thinness, light weight, fast response speed, wide viewing angle, and low driving voltage. Currently, small and medium-sized OLED displays have been widely used in high-end smartphones produced by companies such as Huawei, Xiaomi, and Samsung. Achieving optimal luminous efficiency of the device under low operating voltage conditions is a common requirement in the OLED field.
[0003] Many improvements have been made in the prior art to enable the practical application of organic EL devices. For example, it is well known that high efficiency and high durability can be achieved by further distributing the various functions of the laminated structure and forming an anode, by setting a hole injection layer, a hole transport layer, a hole blocking layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode on a substrate.
[0004] In this organic EL device, charges injected from both electrodes recombine in the emissive layer to produce light emission. In this case, efficiently transferring the charge of holes and electrons to the emissive layer is crucial, and the device requires excellent carrier balance. Furthermore, the luminescence efficiency is improved by enhancing the hole injection and electron blocking properties that impede electrons injected from the cathode to increase the recombination probability, and by confining the excitons generated within the emissive layer. Therefore, the role of the light-emitting auxiliary material is extremely important.
[0005] Research on organic electroluminescent materials has been widely carried out in academia and industry, but so far, a stable and efficient organic layer material for organic electrical components has not been fully developed, and the industrialization process of this technology still faces many key problems. Therefore, how to develop a new light-emitting auxiliary material has always been a problem that needs to be solved by those skilled in the art. Summary of the Invention
[0006] In view of this, one objective of the present invention is to provide a novel organic compound; another objective is to provide a method for synthesizing the novel organic compound; and a third objective is to provide an organic electroluminescent device using the novel organic compound.
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] An organic compound with the structure shown in formulas I-1 and I-2: ; Wherein, R1-R4 may be the same or different from each other, and each of R1-R4 is independently selected from substituted or unsubstituted C1-C20 alkyl groups and substituted or unsubstituted C6-C30 aryl groups; Ar1-Ar4 may be the same as or different from each other, and each of Ar1-Ar4 is independently selected from substituted or unsubstituted C6-C30 aryl groups, substituted or unsubstituted C6-C30 heteroaryl groups, wherein the heteroatom is selected from oxygen, nitrogen, and sulfur.
[0009] Preferably, each of R1-R4 is independently selected from methyl or phenyl.
[0010] Preferably, each of Ar1-Ar4 is independently selected from the following structures and any combination thereof:
[0011] In the above formula, each hydrogen atom is either independently deuterated or undeuterated.
[0012] In this invention, "substitution" means being substituted by one, two or more substituents selected from the following: deuterium, C1-C20 alkyl, C1-C20 alkoxy, C6-C30 aryl, C6-C30 heteroaryl, wherein the heteroatom is selected from oxygen, nitrogen, and sulfur.
[0013] Preferably, the organic compound is selected from any one of the following structures: .
[0014] Another object of the present invention is to provide a method for preparing the above-mentioned organic compounds, wherein the synthetic routes of formula I-1 and formula I-2 are as follows: ; In the above formula, R1-R4 and Ar1-Ar4 are as defined above; Hal1, Hal2, and Hal3 are each independently selected from fluorine, chlorine, bromine, or iodine; The preparation method of Formula I-1 specifically includes: Under N2 protection, raw material A (1.0 eq), raw material B (1.0 eq), tetrakis(triphenylphosphine)palladium (0.01-0.02 eq), and potassium carbonate (2.0-2.2 eq) were added to a mixed solvent of toluene, ethanol, and water, respectively. The mixture was stirred until homogeneous, heated to 90-100℃ and refluxed for 8-10 h. After the reaction was completed, the mixture was cooled to room temperature. After the solid precipitated completely, it was filtered, washed with water to remove salt, rinsed with a small amount of ethanol, dried, and recrystallized in methanol solution to obtain the organic compound shown in Formula I-1. The specific preparation method of Formula I-2 includes: Under N2 protection, starting material C (1.0 eq), starting material D (1.1-1.2 eq), tetrakis(triphenylphosphine)palladium (0.01-0.02 eq), and potassium carbonate (2.0-2.2 eq) were added to DMF solvent, respectively. The mixture was heated to 120-130℃ and reacted for 8-10 h. After the reaction was completed, the mixture was cooled to room temperature, water was added, and the mixture was extracted with ethyl acetate. The organic layer was dried with anhydrous magnesium sulfate, the solvent was removed by rotary evaporation, and the mixture was recrystallized from toluene:ethanol and dried to obtain intermediate 1. Under N2 protection, intermediate 1 (1.0 eq), raw material E (1.0 eq), tetrakis(triphenylphosphine)palladium (0.01-0.02 eq), and potassium carbonate (2.0-2.2 eq) were added to a mixed solvent of toluene, ethanol, and water, respectively. The mixture was stirred until homogeneous, heated to 90-100 °C, and refluxed for 8-10 h. After the reaction was completed, the mixture was cooled to room temperature. After the solid precipitated completely, it was filtered, washed with water to remove salt, rinsed with a small amount of ethanol, dried, and recrystallized in methanol solution to obtain the organic compound shown in Formula I-2.
[0015] Another object of the present invention is to provide an organic electroluminescent device, the organic electroluminescent device comprising an anode, a cathode and an organic layer, the organic layer comprising a light-emitting auxiliary layer, the light-emitting auxiliary layer comprising the aforementioned organic compound.
[0016] Preferably, the organic layer further includes at least one of a hole injection layer, a hole transport layer, a light-emitting layer, a hole blocking layer, an electron transport layer, or a charge generation layer.
[0017] Preferably, the organic layer comprises a first hole injection layer, a first hole transport layer, a first light-emitting auxiliary layer, a first light-emitting layer, a first hole blocking layer, a first electron transport layer, an N-type charge generation layer, a P-type charge generation layer, a second hole transport layer, a second light-emitting auxiliary layer, a second light-emitting layer, a second hole blocking layer, a second electron transport layer, and a second electron injection layer, wherein the first light-emitting auxiliary layer and the second light-emitting auxiliary layer comprise the aforementioned organic compounds.
[0018] As can be seen from the above technical solution, compared with the prior art, the present invention has the following technical effects: The chemical formulas I-1 and I-2 provided by this invention are fluorene compounds with special fluorene structures. As a light-emitting auxiliary layer for red organic light-emitting devices, these compounds can reduce the potential barrier between the hole transport layer and the light-emitting layer, lower the driving voltage of the organic light-emitting device, further improve the hole transport rate and electron blocking ability, and increase the charge balance of holes and electrons in the light-emitting layer. As a result, light is formed well inside the light-emitting layer instead of on the surface of the hole transport layer, thereby greatly improving the device's lifespan and luminous efficiency. Attached Figure Description
[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0020] Figure 1 The image shows the hydrogen NMR spectrum of the compound in Example 1. Detailed Implementation
[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0022] Example 1 Raw material B-14 is not a current technology; the synthetic route is as follows:
[0023] Intermediate raw material B-1 (1.0 eq) (CAS: 583-55-1) and raw material B-2 (1.0 eq) (CAS: 897671-69-1) were dissolved in toluene solution. Pd2(dba)3 (0.01 eq), P(t-Bu)3 (0.5 eq) and t-BuONa (2.0 eq) were added under N2 atmosphere. The temperature was raised to 120℃ and the reaction was stirred for 6 h. After the reaction was completed, the salt and catalyst were removed by hot filtration with diatomaceous earth. After the filtrate was cooled to room temperature, distilled water was added to the filtrate for washing. After separation, the organic phase was retained. The aqueous phase was extracted with ethyl acetate. The combined organic layer was dried with magnesium sulfate and the solvent was removed by rotary evaporator. Finally, the remaining substances were purified by column chromatography using a mixture of dichloromethane and petroleum ether (V:V=1:16) as eluent to obtain raw material B-14.
[0024] Under N2 protection, raw material A-14 (1.0 eq) (CAS: 2776166-19-7), raw material B-14 (1.0 eq), tetrakis(triphenylphosphine)palladium (0.01 eq), and potassium carbonate (2.0 eq) were added to a mixed solvent of toluene, ethanol, and water, respectively. The mixture was stirred until homogeneous, heated to 90 °C, and refluxed for 8 h. After the reaction was completed, the mixture was cooled to room temperature. After the solid precipitated completely, it was filtered, washed with water to remove salt, rinsed with a small amount of ethanol, dried, and recrystallized in methanol solution to obtain compound 14 as shown. The obtained compound 14 was analyzed, and the results are as follows: HPLC purity: >99.95%.
[0025] Mass spectrometry test: Waters XEVO TQD mass spectrometer with ESI source.
[0026] MS(ESI, m / Z): [M+H] + : 705.56.
[0027] Elemental analysis: The calculated values are: C, 91.88; H, 6.14; N, 1.98.
[0028] The test values are: C, 91.15; H, 6.42; N, 2.13.
[0029] Example 2
[0030] The synthesis method of raw material E-149 is the same as that of raw material B-14, and will not be repeated here.
[0031] Under N2 protection, starting materials C-149 (1.0 eq) (CAS: 2922151-73-1), D-149 (1.1 eq) (CAS: 73183-34-3), tetrakis(triphenylphosphine)palladium (0.01 eq), and potassium carbonate (2.0 eq) were added to DMF solvent, heated to 120 °C and reacted for 10 h. After the reaction was completed, the mixture was cooled to room temperature, water was added, and the mixture was extracted with ethyl acetate. The organic layer was dried with anhydrous magnesium sulfate, the solvent was removed by rotary evaporation, and the mixture was recrystallized from toluene:ethanol and dried to obtain intermediate 1. Under N2 protection, intermediate 1 (1.0 eq), starting material E-149 (1.0 eq) (CAS:), tetrakis(triphenylphosphine)palladium (0.01 eq) and potassium carbonate (2.0 eq) were added to a mixed solvent of toluene, ethanol and water, respectively. The mixture was stirred until homogeneous, heated to 90 °C and refluxed for 8 h. After the reaction was completed, the mixture was cooled to room temperature. After the solid precipitated completely, it was filtered, washed with water to remove salt, rinsed with a small amount of ethanol, dried, and recrystallized in methanol solution to obtain compound 149 as shown. The obtained compound 149 was analyzed, and the results are as follows: HPLC purity: >99.95%.
[0032] Mass spectrometry test: Waters XEVO TQD mass spectrometer with ESI source.
[0033] MS(ESI, m / Z): [M+H] + : 705.56.
[0034] Elemental analysis: The calculated values are: C, 91.88; H, 6.14; N, 1.98.
[0035] The test values are: C, 91.08; H, 6.44; N, 2.17.
[0036] Device Application Example 1 Fabrication of red-light organic electroluminescent devices: The structure of the fabricated OLED device is: ITO anode / HIL / HTL / light-emitting auxiliary layer / EML / HBL / ETL / EIL / cathode / light extraction layer; a. ITO anode: The ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate with a coating thickness of 1500 Å was cleaned three times in distilled water and ultrasonically washed for 40 min. Then it was cleaned three times in distilled water and ultrasonically washed for 20 min. After washing, it was ultrasonically washed sequentially with methanol, acetone and isopropanol (5 min each time). After drying, it was transferred to a plasma cleaner for 5 min and then sent to a vapor deposition machine. Using this substrate as the anode, other functional layers were sequentially vapor deposited on it. b. HIL (Hole Injection Layer): Hole injection layer materials HT-1 and P-dopant are vacuum-deposited at a deposition rate of 1 Å / s. The deposition rate ratio of HT-1 to P-dopant is 97:3, and the thickness is 10 nm. c. HTL (hole transport layer): HT-1 of 130 nm was vacuum-deposited on the hole injection layer at a deposition rate of 1.5 Å / s as a hole transport layer. d. Light-emitting auxiliary layer: Compound 14 provided in the above embodiment is vacuum-deposited on the hole transport layer at a deposition rate of 0.5 Å / s for 100 nm as a light-emitting auxiliary layer; e. EML (Light Emitting Layer): Then, on the above-mentioned light-emitting auxiliary layer, a host material (Host1) and a dopant material (Dopant-1) with a total thickness of 40 nm are vacuum-deposited at a deposition rate of 1 Å / s as the light-emitting layer, wherein the deposition rate ratio of the two Host materials to the Dopant-1 materials is 98:2. f. HBL (hole blocking layer): A hole blocking layer HB with a thickness of 5.0 nm is vacuum-deposited at a deposition rate of 0.5 Å / s. g. ETL (Electron Transport Layer): ET-1 and Liq, with a thickness of 35 nm, were vacuum-deposited at a deposition rate of 1 Å / s as the electron transport layer. The chemical formula of ET-1 is shown below. The deposition rate ratio of ET-1 to Liq is 50:50. h. EIL (Electron Injection Layer): A 1.0 nm Yb film is deposited at a deposition rate of 0.5 Å / s to form an electron injection layer; i. Cathode: Magnesium and silver are deposited at a deposition rate of 1 Å / s for 18 nm, with a deposition rate ratio of 1:9, to obtain the OLED device. j. Optical extraction layer: CPL-1 with a thickness of 70 nm was vacuum-deposited on the cathode at a deposition rate of 1 Å / s as the optical extraction layer. 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.
[0037] .
[0038] Device Comparison Examples 1-4 This comparative example provides an organic electroluminescent device. The only difference between this organic electroluminescent device and device example 1 is that the organic electroluminescent device is prepared by evaporation using existing comparative compounds a, b, c, and d instead of the light-emitting auxiliary material (compound 14) in device example 1. Comparative Examples 1-4 are prepared by this method. The chemical structural formulas of comparative compounds a, b, c, and d are as follows: ; The driving voltage, luminous efficiency, and lifetime of the organic electroluminescent devices obtained in Application Examples 1-85 and Comparative Examples 1-4 were characterized at a brightness of 6000 nits. The test results are shown in Table 1 below: Table 1:
[0039] According to the data in Table 1, on the red light device platform of this application, formulas I-1 and I-2 show improvements in both device efficiency and device lifetime compared to the comparative examples. Compound b is a parallel comparative example. Compared with compound b, compounds 14 and 149 differ in the position of the phenyl group. When applied to the device platform of this application, compound 14 shows an 11.9% improvement in device efficiency and an 11.9% improvement in device lifetime, while compound 149 shows a 4.3% improvement in device efficiency and a 20.3% improvement in device lifetime. Compound 14 has a phenyl group at the fluorenyl 1-position, which effectively lowers the energy level and avoids carrier migration localization, thus lowering the HOMO and LUMO energy levels and improving the migration rate. This results in a significant improvement in luminous efficiency while extending device lifetime. Compound 149 has a phenyl group at the fluorenyl 2-position, which effectively enhances the stability of the compound. Compared with the comparative compounds, the improvement in device efficiency and device lifetime is even more significant.
[0040] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.
[0041] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. An organic compound, characterized in that, Its structure is shown in equations I-1 and I-2: ； Wherein, each of R1-R4 is independently selected from substituted or unsubstituted C1-C20 alkyl groups and substituted or unsubstituted C6-C30 aryl groups; Each of Ar1-Ar4 is independently selected from substituted or unsubstituted C6-C30 aryl groups and substituted or unsubstituted C6-C30 heteroaryl groups, wherein the heteroatom is selected from oxygen, nitrogen, and sulfur.
2. An organic compound according to claim 1, characterized in that, Each of R1-R4 is independently selected from methyl or phenyl.
3. An organic compound according to claim 1, characterized in that, Each of Ar1-Ar4 is independently selected from the following structures and any combination thereof: In the above formula, each hydrogen atom is either independently deuterated or undeuterated.
4. An organic compound according to claim 1, characterized in that, The organic compound is selected from any of the following structures: 。 5. A method for preparing the organic compound as described in claim 1, characterized in that, The synthesis routes of Equations I-1 and I-2 are as follows: ； In the above formula, Hal1, Hal2, and Hal3 are each independently selected from fluorine, chlorine, bromine, or iodine; The preparation method of Formula I-1 specifically includes: Under N2 protection, raw material A, raw material B, tetrakis(triphenylphosphine)palladium and potassium carbonate were added to a mixed solvent of toluene, ethanol and water, respectively, stirred evenly, and refluxed at 90-100℃ for 8-10 hours. After treatment, the organic compound shown in Formula I-1 was obtained. The specific preparation method of Formula I-2 includes: Under N2 protection, raw material C, raw material D, tetra(triphenylphosphine)palladium and potassium carbonate were added to DMF solvent, and the mixture was heated to 120-130℃ and reacted for 8-10 hours. After processing, intermediate 1 was obtained. Under N2 protection, intermediate 1, raw material E, tetra(triphenylphosphine)palladium and potassium carbonate were added to a mixed solvent of toluene, ethanol and water, respectively. The mixture was stirred until homogeneous and then refluxed at 90-100℃ for 8-10 hours. After processing, the organic compound shown in Formula I-2 was obtained.
6. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes an anode, a cathode, and an organic layer, wherein the organic layer includes a light-emitting auxiliary layer, and the light-emitting auxiliary layer includes an organic compound as described in any one of claims 1-4.
7. The organic electroluminescent device according to claim 6, characterized in that, The organic layer further includes at least one of a hole injection layer, a hole transport layer, a light-emitting layer, a hole blocking layer, an electron transport layer, or a charge generation layer.
8. The organic electroluminescent device according to claim 6, characterized in that, The organic layer comprises a first hole injection layer, a first hole transport layer, a first light-emitting auxiliary layer, a first light-emitting layer, a first hole blocking layer, a first electron transport layer, an N-type charge generation layer, a P-type charge generation layer, a second hole transport layer, a second light-emitting auxiliary layer, a second light-emitting layer, a second hole blocking layer, a second electron transport layer, and a second electron injection layer, wherein the first light-emitting auxiliary layer and the second light-emitting auxiliary layer comprise any one of the organic compounds described in claims 1-4.