A pyrrolophenazine nitrogen-containing heterocyclic compound, a light-emitting composition, and an organic electroluminescent device

Abstract

The application discloses a pyrrolophenazine nitrogen-containing heterocyclic compound, a light-emitting composition and an organic electroluminescent device, relates to the technical field of organic optoelectronic materials and devices, and the pyrrolophenazine nitrogen-containing heterocyclic compound is a compound with a structure as shown in a general formula (1): the compound is a pyrrolophenazine skeleton-containing nitrogen-containing heterocyclic compound, has the characteristics of high performance and narrow emission spectrum, and can be applied to preparation of an organic electroluminescent device or an illumination element.

Description

Technical Field

[0001] This invention relates to the field of organic optoelectronic materials and devices, and particularly to a pyrrolophenazine nitrogen-containing heterocyclic compound, a luminescent composition, and an organic electroluminescent device. Background Technology

[0002] Organic light-emitting diode (OLED) technology is a technique that uses organic semiconductor thin films to emit light under an applied voltage. It boasts numerous advantages, including flexibility, self-illumination, thinness, and low power consumption, and has been widely applied in smartphones, wearable devices, and automotive displays. Organic light-emitting materials, as a crucial part of the OLED display technology industry chain, represent a significant technological barrier; therefore, exploring OLED light-emitting materials that meet the requirements of display panels is of paramount importance.

[0003] With the continuous development and iteration of OLED display technology, next-generation display technologies require OLED luminescent materials to possess properties such as high luminous efficiency, long lifespan, and high color purity. Among these, blue OLED materials represent a significant technological challenge, with the greatest difficulties in achieving high efficiency, long lifespan, and high color purity. Based on their light-emitting mechanisms, OLED luminescent materials can be categorized into traditional fluorescent materials, phosphorescent materials, and thermally activated delayed fluorescence materials. However, currently, blue materials struggle to simultaneously achieve high luminous efficiency, long lifespan, and high color purity across different light-emitting mechanisms. Furthermore, while blue molecules employing phosphorescence and thermally activated delayed fluorescence mechanisms can achieve high emission efficiency, the materials suffer from wide spectral widths and insufficient stability, hindering their commercial application. Traditional blue fluorescent systems, while possessing good device lifespans, suffer from insufficient luminous efficiency. Therefore, improving the color purity and reducing the full width at half maximum (FWHM) of blue materials remains a key challenge.

[0004] Currently, high-performance commercially available blue fluorescent materials mainly use pyrene, stilbene, and derivatives composed of these groups as the luminescent core. By matching appropriate aromatic amine charge-donating units for modification, the charge transfer state and emission color of the molecule can be controlled, leading to the design of a series of highly efficient new blue fluorescent materials. In recent years, a blue fluorescent material constructed with indolocarbazole as the molecular skeleton has attracted attention. This type of material has the following characteristics in achieving high-performance blue light materials: First, because the indolocarbazole luminescent core has a rigid and planar molecular skeleton, the half-width of the molecule's emission spectrum is relatively small (see J. Mater. Chem. C, 2019, 7, 14301., KR 1020180000323, CN110627822A, CN110291654A, US20190221747A1). Since indolocarbazole itself emits light in the blue-violet region, it requires the introduction of π-conjugated units to bridge the spectrum or the addition of charged units to redshift the spectrum to the blue region (see US Patent, 1992, US5151629, Appl. Phys. Lett., 1999, 75, 4055., Chem. Sci., 2016, 7, 4044., Org. Electron., 2019, 70, 1., and Appl. Mater. Inter., 2017, 9, 26268.). However, this strategy tends to excite spectral vibrational peaks in the molecule, leading to enhanced spectral broadening, which is detrimental to achieving high-purity blue light materials for display applications.

[0005] It is evident that existing technologies still need improvement and enhancement. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a pyrrolophenazine nitrogen-containing heterocyclic compound, a luminescent composition and an organic electroluminescent device, which aims to solve the defects of existing blue light-emitting organic light-emitting materials, such as large spectral half-width and insufficient luminous efficiency.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] The first aspect of this invention provides a pyrrolophenazine nitrogen-containing heterocyclic compound having the structure of general formula (1):

[0009]

[0010] Where X1 to X6 are independently represented as nitrogen atoms or carbon atoms, and the number of nitrogen atoms is taken from integers from 0 to 4;

[0011] The substitution sites for substituents R1 and R2 are X. n For any position of a carbon atom, n is an integer from 1 to 6;

[0012] Substituents R1 and R2 are each independently selected from phenyl or biphenyl and their derivatives, fused-ring phenyl with 2 to 6 benzene rings and their derivatives, phenanthroline and its derivatives, pyridine and its derivatives, pyrimidine and its derivatives, triazine and its derivatives, pyrazine and its derivatives, fluorenyl and its derivatives, thiophene and its derivatives, furan and its derivatives, imidazole and its derivatives, indole and its derivatives, carbazole and its derivatives, indole-carbazole and its derivatives, boron nitrogen and its derivatives, aniline and its derivatives, acridine and its derivatives, phenazine and its derivatives, phenothiazine and its derivatives, phenoteneselene and its derivatives, thiathracene and its derivatives, thioxanthracene and its derivatives, oxanthracene and its derivatives, phenoteneselene and its derivatives, phenothiazine and its derivatives, and selenium and its derivatives.

[0013] R3 to R6 are each independently a hydrogen atom, a deuterium atom, a tritium atom, a halogen atom, a cyano group, a substituted or unsubstituted alkyl group with 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group with 3 to 20 carbon atoms, a substituted or unsubstituted alkoxy group with 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group with 6 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group with 6 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group with 6 to 50 carbon atoms, or a substituted or unsubstituted heteroaryl group with 5 to 50 carbon atoms, aniline and its derivatives, carbazole and its derivatives, indolecarbazole and its derivatives, boron nitrogen and its derivatives, acridine and its derivatives, benzothiophene and its derivatives, benzofuran and its derivatives, fluorenyl and its derivatives, phenoxazine and its derivatives, phenothiazine and its derivatives, phenyl or biphenyl and its derivatives.

[0014] A second aspect of the present invention provides a luminescent composition comprising a guest material and a host material; wherein the guest material is a nitrogen-containing heterocyclic compound of pyrrolophenazine as described above, and the mass percentage of the guest material is 0.3 to 20.0%.

[0015] The third invention provides an organic electroluminescent device, comprising a substrate, and an anode layer, an organic light-emitting functional layer, and a cathode layer sequentially formed on the substrate. The organic light-emitting functional layer includes any one or a combination of a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer. The light-emitting layer is located between the hole transport layer and the electron transport layer. The light-emitting layer includes the pyrrolophenazine nitrogen-containing heterocyclic fused ring compound as described above, or the light-emitting composition as described above.

[0016] Beneficial effects:

[0017] The present invention provides a pyrrolophenazine nitrogen-containing heterocyclic compound, which has the following beneficial effects: 1) The compound uses pyrrolophenazine as its molecular backbone, which has strong rigidity and a short π-conjugated structure, suppressing the broadening of the molecular emission spectrum and giving it a small spectral half-width; 2) By introducing an auxiliary chromophore onto the molecular backbone, the molecular emission color is modulated to the blue light region. Since the frontier orbital electron cloud is not excessively distributed on the auxiliary chromophore, the above-mentioned pyrrolophenazine nitrogen-containing heterocyclic compound still maintains narrow emission spectral characteristics. Furthermore, by attaching an auxiliary chromophore to a specific substitution site of the phenyl group in the pyrrolophenazine backbone... The auxiliary chromophore can regulate the π-conjugation length between the auxiliary chromophore and pyrrolopyrazine, which helps to suppress spectral vibration peaks while maintaining a strong transition dipole intensity, thus achieving narrow spectrum and high-efficiency emission; 3) Introducing nitrogen atoms into the phenyl unit of the pyrrolopyrazine molecular skeleton can further enhance the molecular transition dipole intensity, which is beneficial to improving the luminescence efficiency of pyrrolopyrazine nitrogen-containing heterocyclic compounds, while also maintaining narrow spectrum luminescence characteristics; 4) By incorporating non-coplanar auxiliary chromophores into the pyrrolopyrazine molecular skeleton, the stacking effect between pyrrolopyrazine molecules can be effectively avoided, and the aggregation luminescence quenching caused by the stacking effect can be suppressed. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of an organic electroluminescent device.

[0019] Figure 2 This is the photoluminescence spectrum of compound 5-22 in toluene solution.

[0020] In the attached diagram, the following labels are used: 10, anode layer; 11, hole injection layer; 12, hole transport layer; 13, light-emitting layer; 14, second electron transport layer; 15, first electron transport layer; 16, electron injection layer; 17, cathode layer. Detailed Implementation

[0021] This invention provides a pyrrolophenazine nitrogen-containing heterocyclic compound, a luminescent composition, and an organic electroluminescent device. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the following embodiments are provided for further detailed explanation. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention.

[0022] This invention provides a nitrogen-containing heterocyclic compound of pyrrolophenazine, wherein the heterocyclic compound is a compound having the general formula (1):

[0023]

[0024] Where X1 to X6 are independently represented as nitrogen atoms or carbon atoms, and in X1 to X... 6+In this context, the number of nitrogen atoms is taken from an integer between 0 and 4. That is, within X1 to X6, it can be all carbon atoms; it can be one nitrogen atom and the other five carbon atoms; it can be two nitrogen atoms and the other four carbon atoms; it can be three nitrogen atoms and three carbon atoms; or it can be four nitrogen atoms and the other two carbon atoms. This is achieved by changing the number of nitrogen atoms and the range from X1 to X6. 6+ The position of the peak is determined to obtain a narrower spectral half-width.

[0025] In general formula (1), the substitution sites of substituents R1 and R2 are X. n For any position of a carbon atom, X n In this context, n is an integer from 1 to 6, meaning that the substitution site of R1 can be any carbon atom among positions X1 to X3, while the substitution site of R2 can be any carbon atom among positions X4 to X6. Furthermore, by adjusting the substitution sites of substituents R1 and R2, a narrower spectral half-width and higher luminescence efficiency can be obtained.

[0026] In general formula (1), substituents R1 and R2 are each independently selected from phenyl or biphenyl and their derivatives, fused-ring phenyl with 2 to 6 rings and their derivatives, phenanthroline and its derivatives, pyridine and its derivatives, pyrimidine and its derivatives, triazine and its derivatives, pyrazine and its derivatives, fluorenyl and its derivatives, thiophene and its derivatives, furan and its derivatives, imidazole and its derivatives, indole and its derivatives, carbazole and its derivatives, indole-carbazole and its derivatives, boron nitrogen and its derivatives, aniline and its derivatives, acridine and its derivatives, phenazine and its derivatives, phenothiazine and its derivatives, phenoteneselene and its derivatives, thiaanthracene and its derivatives, thioxanthracene and its derivatives, phenoteneselene and its derivatives, phenothiazine and its derivatives, selenium and its derivatives, but are not limited to the aforementioned groups, and may also be other electron-donating groups, to change the emission color region to the blue light region, or to reduce the half-peak width of the spectrum.

[0027] In general formula (1), R3 to R6 are each independently a hydrogen atom, a deuterium atom, a tritium atom, a halogen atom, a cyano group, a substituted or unsubstituted alkyl group with 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group with 3 to 20 carbon atoms, a substituted or unsubstituted alkoxy group with 1 to 20 carbon atoms, a substituted or unsubstituted aryl group with 6 to 50 carbon atoms, a substituted or unsubstituted aryloxy group with 6 to 50 carbon atoms, a substituted or unsubstituted arylboryl group with 6 to 50 carbon atoms, or a substituted or unsubstituted alkyl group. The groups may be heteroaryl groups with 5 to 50 ring atoms, aniline and its derivatives, carbazole and its derivatives, indole-carbazole and its derivatives, boron nitrogen and its derivatives, acridine and its derivatives, benzothiophene and its derivatives, benzofuran and its derivatives, fluorenyl and its derivatives, phenoxazine and its derivatives, phenothiazine and its derivatives, phenyl or biphenyl and its derivatives, but are not limited to the aforementioned groups. Other donating groups may also be used to change the emission color region to the blue light region or to reduce the full width at half maximum (FWHM) of the spectrum.

[0028] The aforementioned nitrogen-containing heterocyclic compound with general formula (1) uses pyrrolophenazine as its backbone, which can suppress molecular stretching vibrations and molecular conformational relaxation caused by π conjugation, thus effectively solving the problem of emission spectrum broadening and achieving a smaller spectral half-width. Furthermore, by introducing an auxiliary chromophore with an electron-donating substituent onto the molecular backbone, the luminescence color of the molecule can be controlled to the blue region. Moreover, by attaching auxiliary chromophores to different substitution sites of the phenyl group in the pyrrolophenazine backbone, the π conjugation length between the auxiliary chromophore and the pyrrolophenazine can be controlled, so that the electron cloud is still mainly localized on the pyrrolophenazine backbone. This is beneficial for suppressing spectral vibration peaks while maintaining strong S0-S1 and S1-S0 transition dipole intensities, achieving the molecular design goal of narrow spectrum and high-efficiency luminescence. At the same time, it suppresses the spectral broadening behavior caused by the auxiliary chromophore, resulting in a narrower spectral half-width and the emission of blue light with higher purity.

[0029] In a preferred embodiment, the pyrrolophenazine nitrogen-containing heterocyclic compound can be any one of the compounds of formulas (2-1), (2-2), and (2-3):

[0030]

[0031] It can also be a compound with the structural formula shown in formula (3-1) or (3-2):

[0032]

[0033] In formulas (2-1), (2-2), (2-3), (3-1), and (3-2), the substituents R1 and R2, and R3 to R6 are defined in the same way as in formula (1).

[0034] In a preferred embodiment, substituents R1 and R2 are each independently selected from any one of the following substituent groups:

[0035]

[0036] In the aforementioned equations (4-1) to (4-12), Y, Z, and Q are each independently selected from C(R). 41 (R) 42 ), NR 43 O, S, Se, Si(R) 44 (R) 45 One of them;

[0037] Q1 is independently selected from any one of the following: substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 20 carbon atoms, substituted or unsubstituted aryl groups having 6 to 50 carbon atoms, and substituted or unsubstituted heteroaryl groups having 5 to 50 carbon atoms.

[0038] P1~P 20 Each of the following is independently composed of a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted alkyl group with 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group with 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group with 3 to 20 carbon atoms, an amino group, a substituted or unsubstituted alkoxy group with 1 to 20 carbon atoms, a substituted or unsubstituted fluoroalkyl group with 1 to 20 carbon atoms, a substituted or unsubstituted fluoroalkoxy group with 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group with 6 to 50 carbon atoms, a substituted or unsubstituted alkylthio group with 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group with 6 to 50 carbon atoms, or -N(R 101 (R) 102 ), any one of substituted or unsubstituted aryl groups having 6 to 50 carbon atoms and substituted or unsubstituted heteroaryl groups having 5 to 50 carbon atoms;

[0039] L is one of the following: substituted or unsubstituted alkyl with 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl with 3 to 20 carbon atoms, substituted or unsubstituted aryl with 6 to 50 carbon atoms, and substituted or unsubstituted heteroaryl with 5 to 50 carbon atoms; and in formulas (4-1) to (4-12), n is an integer from 0 to 3.

[0040] Furthermore, in this embodiment, R 41 R 42 R 43 R 44 R 45 R 101 R 102 Each is independently a substituent of an alkyl or aromatic ring.

[0041] In a preferred embodiment, the pyrrolophenazine nitrogen-containing heterocyclic compound is selected from one of the following formulas (5-1) to (5-54), but is not limited to the following structural formulas:

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050] The aforementioned pyrrolophenazine nitrogen-containing heterocyclic compounds all have pyrrolophenazine as their backbone structure and can emit pure blue light through the action of auxiliary chromophores with electron-donating properties. They also have a narrow spectral half-width and high luminous efficiency, and can be used as luminescent materials.

[0051] To demonstrate that the aforementioned pyrrolophenazine nitrogen-containing heterocyclic compounds possess narrow emission spectral characteristics and high fluorescence quantum yield, compound (5-22) is used as an example. Comparative compounds 1, 2, and 3 are also used as comparative examples for performance testing. Figure 2 As shown, at room temperature, the compound with structural formula (5-22) exhibits an emission peak at 453 nm and a spectral half-width of 15 nm in toluene solution (concentration 1×10⁻⁵ M), with a fluorescence quantum yield of 96%. Comparative compounds 1, 2, and 3, on the other hand, have emission peaks of 454 nm, 458 nm, and 469 nm, respectively, with spectral half-widths of 19 nm, 23 nm, and 18 nm, and fluorescence quantum yields of 89%, 90%, and 93%, respectively. Therefore, the pyrrolophenezine nitrogen-containing heterocyclic fused-ring compound described in this application exhibits a higher fluorescence quantum yield and a narrower emission spectrum compared to other nitrogen-containing heterocyclic compounds and narrow-spectrum boron-nitrogen compounds. This indicates that the pyrrolophenezine nitrogen-containing heterocyclic compound described in this application possesses high fluorescence quantum yield and narrow-emission deep blue light emission characteristics.

[0052] The specific structural formulas of compounds 1-3 are as follows:

[0053]

[0054] A second aspect of the present invention also provides a luminescent composition comprising a guest material and a host material; the guest material is a nitrogen-containing heterocyclic compound of pyrrolophenazine as described above, which has luminescent properties, emits blue light, and has a narrow half-maximum width at half maximum (WHM); the host material can be a fluorescent luminescent material or a thermally active delayed fluorescence mechanism material, and a better luminescent effect is obtained by doping the guest material into the host material; the mass percentage of the guest material is 0.3% to 20.0%.

[0055] To achieve better luminescence, the host material is selected from the following compounds:

[0056]

[0057]

[0058]

[0059] In a preferred embodiment, the luminescent composition further includes an auxiliary host material, the main function of which is to improve the luminescence efficiency of the guest material and enhance exciton utilization efficiency.

[0060] In a preferred embodiment, in the luminescent composition containing the auxiliary host material, the mass percentage of the guest material is 0.3-10.0%, the mass percentage of the host material is 30.0-94.7%, and the mass percentage of the auxiliary host material is 5.0-60.0%. The luminescent composition obtained by combining these components has a superior luminescent effect.

[0061] In a preferred embodiment, in the aforementioned luminescent composition containing an auxiliary host material, the host material is selected from, but not limited to, one of the following compounds:

[0062]

[0063]

[0064] The auxiliary host material is selected from one of the following compounds, but is not limited to the following compounds:

[0065]

[0066]

[0067]

[0068] A third aspect of the present invention also provides an organic electroluminescent device, comprising: a substrate, an anode layer formed on the substrate, an organic light-emitting functional layer, and a cathode layer; the organic light-emitting functional layer comprises any one or a combination of a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer, the light-emitting layer being located between the hole transport layer and the electron transport layer, the raw material composition of the light-emitting layer comprising the nitrogen-containing heterocyclic compound of pyrrolophenazine as described above, or the raw material for preparing the light-emitting layer is the aforementioned light-emitting composition, which can emit blue light with a narrow emission spectrum.

[0069] Specifically, the anode layer is used to inject holes into the hole transport layer or the light-emitting layer. It is usually made of materials with a work function greater than 4.5 eV, such as indium tin oxide (ITO), tin oxide (NESA), indium gallium zinc oxide (IGZO), silver, etc. These materials can be used to form anode layer thin films by thermal evaporation, sputtering, etc.

[0070] Furthermore, in a preferred embodiment, the light transmittance of the visible area of ​​the anode layer is greater than 80%, and its sheet resistance is less than 500 Ω / cm. -1 The film thickness is 10–200 nm, and it has good hole injection efficiency.

[0071] Specifically, the cathode layer is used to inject electrons into the electron injection layer, electron transport layer, or light-emitting layer, and it is typically made of a material with a low work function, such as aluminum, magnesium, silver, magnesium-silver alloys, magnesium-aluminum alloys, or aluminum-lithium alloys. The cathode layer can also be formed into a thin film by thermal evaporation, sputtering, or other methods, and the film thickness of the cathode layer is preferably selected in the range of 10–200 nm.

[0072] The electron injection layer is used to promote the injection of electrons from the cathode layer to the electron transport layer or the light-emitting layer, thereby improving the luminous brightness and lifetime of the organic electroluminescent device. As a preferred option, the electron injection layer is prepared by thermal evaporation using a material with a work function less than 3.8 eV, such as Li, Cs, Ba, Yb, LiF, CsF, BaO, etc., and the film thickness of the electron injection layer is preferably 0.1–15 nm.

[0073] The electron transport layer is disposed between the light-emitting layer and the cathode layer (or electron injection layer), and is used to transport electrons from the cathode or electron injection layer to the light-emitting layer. The electron transport layer may consist of one or two organic layers. When it consists of two organic layers, the organic layer closer to the cathode layer is defined as the first electron transport layer, and the organic layer closer to the light-emitting layer is defined as the second electron transport layer. Preferably, the electron transport layer is an aromatic heterocyclic compound containing one or more heteroatoms within its molecule, and more preferably a nitrogen-containing ring derivative. Furthermore, as a nitrogen-containing ring derivative, it is preferably an aromatic ring having a nitrogen-containing six-membered or five-membered ring skeleton, or a fused aromatic ring compound having a nitrogen-containing six-membered or five-membered ring skeleton.

[0074] The thickness of the electron transport layer is generally 10–100 nm. When the electron transport layer consists of a first electron transport layer and a second electron transport layer, the thickness of the first electron transport layer is preferably 9–70 nm, and the thickness of the second electron transport layer is preferably 1–30 nm.

[0075] The hole transport layer is an organic layer disposed between the light-emitting layer and the anode layer (or hole injection layer), and its main function is to transport holes from the anode to the light-emitting layer. The hole transport layer may consist of one organic layer material or two organic layer materials. When it consists of two organic layers, the organic layer closer to the anode layer is defined as the first hole transport layer, and the organic layer closer to the light-emitting layer is defined as the second hole transport layer.

[0076] Preferably, the hole transport layer is prepared from an aromatic amine compound, such as an aromatic amine derivative with the structural formula (70) or (71).

[0077]

[0078] These aromatic amine derivatives have better hole transport efficiency.

[0079] The thickness of the hole transport layer is generally 20–200 nm. When the hole transport layer consists of a first hole transport layer and a second hole transport layer, the thickness of the first hole transport layer is preferably 19–150 nm, and the thickness of the second hole transport layer is preferably 1–50 nm.

[0080] Specifically, the hole injection layer is disposed between the anode layer and the hole transport layer (or light-emitting layer) to promote hole injection from the anode layer to the hole transport layer or light-emitting layer, thereby reducing the driving voltage of the organic electroluminescent device and improving its brightness and lifetime. The hole injection layer is typically prepared using acceptor-type organic materials containing deep LUMO energy levels, such as HATCN, F4TCNQ, and HI-3, and its thickness is generally 1–50 nm.

[0081] The structural formulas of HATCN, F4-TCNQ, and HI-3 are as follows:

[0082]

[0083] In a preferred embodiment, the organic electroluminescent device further incorporates an n-type dopant in the electron transport layer and a p-type dopant in the hole transport layer. The main functions of the n-type and p-type dopant are to enhance the transport properties of the electron and hole transport layers, respectively, and to reduce the driving voltage of the organic electroluminescent device. Here, the n-type dopant can be selected from Li, Cs, Ba, Yb, CsF, BaO, Liq, Naq, Libpp, Bepq2, Bepp2, LiF, CsCO3, and ZnO; the p-type dopant can be selected from HATCN, F4TCNQ, and HI-3, but is not limited to these substances. When the hole transport layer contains the p-type dopant and hole transport material, the doping concentration of the p-type dopant is preferably 0.1% to 50.0% by mass; when the hole transport layer contains the n-type dopant and electron transport material, the doping concentration of the n-type dopant is preferably 1.0% to 90.0% by mass.

[0084] The preferred n-type dopant materials Liq, Naq, Libpp, Bepq2, and Bepp2 for the organic electroluminescent devices of this application have the following structural formulas:

[0085]

[0086]

[0087] In summary, the organic electroluminescent device prepared by the present invention using pyrrolophenazine nitrogen-containing heterocyclic compounds as the raw material for the luminescent layer has the following beneficial effects: 1) The pyrrolophenazine molecular skeleton itself has strong rigidity and a short π-conjugated structure, which suppresses the broadening of the molecular emission spectrum, resulting in a smaller spectral half-width; 2) Introducing substituents to the molecular skeleton to assist chromophores modulates the molecular emission color to the blue light region. Since the frontier orbital electron cloud is not excessively distributed on the auxiliary chromophore, the aforementioned pyrrolophenazine nitrogen-containing heterocyclic fused-ring compound still maintains narrow emission spectral characteristics; furthermore, we preferably have a specific phenyl group in the pyrrolophenazine skeleton. By incorporating auxiliary chromophores at substitution sites, the π-conjugation length between the auxiliary chromophore and pyrrolopyrazine can be controlled, which helps to suppress spectral vibration peaks while maintaining strong transition dipole intensity, thus achieving narrow spectrum and high-efficiency emission; 3) Introducing nitrogen atoms to the phenyl units of the pyrrolopyrazine molecular skeleton can further enhance the molecular transition dipole intensity, which helps to improve the luminescence efficiency of the above-mentioned nitrogen-containing heterocyclic fused ring compounds of pyrrolopyrazine, while also maintaining narrow spectrum luminescence characteristics; 4) Incorporating auxiliary chromophores in different planes into the pyrrolopyrazine molecular skeleton can effectively avoid the stacking effect between pyrrolopyrazine molecules and suppress the aggregation luminescence quenching caused by the stacking effect.

[0088] To further illustrate the nitrogen-containing pyrrolopyrazine provided by the present invention, the following examples are provided.

[0089] Examples 1-10

[0090] Examples 1-10 are all nitrogen-containing heterocyclic compounds of pyrrolophenazine. The specific compounds, their elemental analyses, and molecular weights are shown in Table 1.

[0091] Table 1

[0092]

[0093]

[0094] The synthesis methods of the compounds corresponding to each embodiment are as follows:

[0095] Example 1

[0096]

[0097] Add 1 (1.15 g, 5 mmol), CuI (0.309 g, 1 mmol, 20 mol%), Phen (0.180 g, 1.0 mmol, 20 mol%), and anhydrous Cs₂CO₃ (2.44 g, 7.5 mmol) to 10 mL of o-DCB and heat to 180 °C. Stir for 24 h under nitrogen protection. After cooling to room temperature, wash a silica gel column with a large amount of DCM to remove CuI and Cs₂CO₃ and collect the filtrate. Remove the solvent by vacuum distillation. Then, purify the product by silica gel column chromatography with dichloromethane / petroleum ether (volume 1:3) as the developing solvent. Concentrate by rotary evaporation to obtain 2 (0.150 g, 14%) as a yellow-green powder.

[0098] A mixture of 2 (0.30 g, 1.0 mmol), diphenylamine (0.51 g, 3.0 mmol), Pd2(dba)3 (0.046 g, 0.05 mmol, 5 mol%), S-phos (0.082 g, 0.2 mmol, 20 mol%), and NaOtBu (0.38 g, 4.0 mmol) was heated to 140 °C in 60 mL of Xylenen:DMF (2:1 v / v) co-solvent and heated under a nitrogen stream for 24 h. The reaction mixture was extracted with ethyl acetate upon cooling, dried over anhydrous sodium sulfate, and concentrated by rotary evaporation. The crude product was purified by silica gel column chromatography using ethyl acetate / petroleum ether (1:20 v / v) as eluent to give a yellow solid 5-11 (0.45 g, 81%).

[0099] Example 2

[0100]

[0101] The synthesis of compound 4 was similar to that of compound 2. Compound 3 (1.15 g, 5 mmol), CuI (0.309 g, 1 mmol, 20 mol%), Phen (0.180 g, 1.0 mmol, 20 mol%), and anhydrous Cs₂CO₃ (2.44 g, 7.5 mmol) were added to 10 mL of o-DCB and heated to 180 °C. The mixture was stirred for 24 h under nitrogen protection. After cooling to room temperature, the silica gel column was washed with a large amount of DCM to remove CuI and Cs₂CO₃, and the filtrate was collected. The solvent was then removed by vacuum distillation. The product was then purified by silica gel column chromatography with a dichloromethane / petroleum ether ratio of 1:3 (v / v). The product was concentrated by rotary evaporation to obtain compound 4 (0.120 g, 12%) as a yellow-green powder.

[0102] The synthesis of compound 5-12 was similar to that of 5-11. A mixture of 4 (0.30 g, 1.0 mmol), diphenylamine (0.51 g, 3.0 mmol), Pd2(dba)3 (0.046 g, 0.05 mmol, 5 mol%), S-phos (0.082 g, 0.2 mmol, 20 mol%), and NaOtBu (0.38 g, 4.0 mmol) was heated to 140 °C in 60 mL of Xylenen:DMF (2:1 v / v) cosolvent under a nitrogen stream for 24 h. The reaction mixture was extracted with ethyl acetate upon cooling, dried over anhydrous sodium sulfate, and concentrated by rotary evaporation. The crude product was purified by silica gel column chromatography using ethyl acetate / petroleum ether (1:20 v / v) as the eluent to give 5-11 (0.37 g, 76%) as a yellow solid.

[0103] Example 3

[0104]

[0105] The synthesis of compound 5 was similar to that of compound 2. Compound 1 (1.15 g, 5 mmol), compound 3 (1.15 g, 5 mmol), CuI (0.618 g, 2 mmol, 20 mol%), Phen (0.360 g, 2.0 mmol, 20 mol%), and anhydrous Cs₂CO₃ (4.88 g, 15 mmol) were added to 10 mL of Lo-DCB and heated to 180 °C. The mixture was stirred for 24 h under nitrogen protection. After cooling to room temperature, the silica gel column was washed with a large amount of DCM to remove CuI and Cs₂CO₃, and the filtrate was collected. The solvent was then removed by vacuum distillation. The product was then purified by silica gel column chromatography with an eluent ratio of DCM:PE = 1:2 (v / v). The product was concentrated by rotary evaporation to obtain compound 5 (0.240 g, 16%) as a yellow-green powder.

[0106] The synthesis of compound 5-14 was similar to that of 5-11. A mixture of 5 (0.30 g, 1.0 mmol), diphenylamine (0.51 g, 3.0 mmol), Pd2(dba)3 (0.046 g, 0.05 mmol, 5 mol%), S-phos (0.082 g, 0.2 mmol, 20 mol%), and NaOtBu (0.38 g, 4.0 mmol) was heated to 140 °C in 60 mL of Xylenen:DMF (2:1 v / v) co-solvent and heated under a nitrogen stream for 24 h. The reaction mixture was extracted with ethyl acetate upon cooling, dried over anhydrous sodium sulfate, and concentrated by rotary evaporation. The crude product was purified by silica gel column chromatography using ethyl acetate / petroleum ether (1:20 v / v) as eluent to give 5-14 (0.42 g, 79%) as a yellow solid.

[0107] Example 4

[0108]

[0109] Add 6 (2.09 g, 10 mmol), 7 (2.81 g, 11 mmol), and Cs2CO3 (4.88 g, 15 mmol) 、 A mixture of Pd(OAc)₂ (0.22 g, 1.0 mmol) and S-Phos (0.53 g, 1.0 mmol) was heated at 100 °C for 24 hours in 15 mL of toluene solution. The reaction mixture was extracted with DCM under cooling. The organic phase was dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated by rotary evaporation. The product was then purified by silica gel column chromatography with dichloromethane / petroleum ether (volume 1:5) as the developing solvent. The product was concentrated by rotary evaporation to give β (2.53 g, 63.09%) as a white powder.

[0110] The synthesis of compound 5-17 was similar to that of 5-11. A mixture of 2 (0.30 g, 1 mmol), 8 (0.81 g, 2 mmol), Pd2(dba)3 (0.046 g, 0.05 mmol, 5 mol%), S-phos (0.082 g, 0.2 mmol, 20 mol%), and NaOtBu (0.38 g, 4.0 mmol) was heated to 140 °C in 60 mL of Xylenen:DMF (2:1 v / v) cosolvent and heated under a nitrogen stream for 24 h. The reaction mixture was extracted with ethyl acetate upon cooling, dried over anhydrous sodium sulfate, and concentrated by rotary evaporation. The crude product was purified by silica gel column chromatography using ethyl acetate / petroleum ether (1:20 v / v) as eluent to give a yellow-green powder 5-17 (0.83 g, 81%).

[0111] Example 5

[0112]

[0113] The synthesis of compound 10 was similar to that of compounds 5-11. A mixture of 5 (0.30 g, 1 mmol), 9 (0.29 g, 1.1 mmol), Pd2(dba)3 (0.046 g, 0.05 mmol, 5 mol%), S-phos (0.082 g, 0.2 mmol, 20 mol%), and NaOtBu (0.38 g, 4.0 mmol) was heated to 140 °C in 60 mL of Xylenen:DMF (2:1 v / v) cosolvent under a nitrogen atmosphere for 24 h. The reaction mixture was extracted with ethyl acetate upon cooling, dried over anhydrous sodium sulfate, and concentrated by rotary evaporation. The crude product was purified by silica gel column chromatography using ethyl acetate / petroleum ether (1:20 v / v) as the eluent to give 10 (0.42 g, 77%) as a yellow-green powder.

[0114] The synthesis of compound 5-17 was similar to that of 5-11. A mixture of 10 (0.54 g, 1 mmol), 8 (0.41 g, 1.1 mmol), Pd2(dba)3 (0.046 g, 0.05 mmol, 5 mol%), S-phos (0.082 g, 0.2 mmol, 20 mol%), and NaOtBu (0.38 g, 4.0 mmol) was heated to 140 °C in 60 mL of Xylenen:DMF (2:1 v / v) cosolvent under a nitrogen atmosphere for 24 h. The reaction mixture was extracted with ethyl acetate upon cooling, dried over anhydrous sodium sulfate, and concentrated by rotary evaporation. The crude product was purified by silica gel column chromatography using ethyl acetate / petroleum ether (1:20 v / v) as eluent to give a yellow-green powder 5-22 (0.78 g, 85%).

[0115] Example 6

[0116]

[0117] The synthesis of compound 5-26 was similar to that of 5-11. A mixture of 4 (0.30 g, 1 mmol), 11 (0.21 g, 1.1 mmol), Pd2(dba)3 (0.046 g, 0.05 mmol, 5 mol%), S-phos (0.082 g, 0.2 mmol, 20 mol%), and NaOtBu (0.38 g, 4.0 mmol) was heated to 140 °C in 60 mL of Xylenen:DMF (2:1 v / v) co-solvent and heated under a nitrogen stream for 24 h. The reaction mixture was extracted with ethyl acetate upon cooling, dried over anhydrous sodium sulfate, and concentrated by rotary evaporation. The crude product was purified by silica gel column chromatography using ethyl acetate / petroleum ether (1:20 v / v) as the eluent to give 5-26 (0.56 g, 87%) as a yellow-green powder.

[0118] Example 7

[0119]

[0120] A mixture of compound 12 (0.32 g, 1 mmol), bis(pinarate)diborane (0.38 g, 1.5 mmol), KOAc (0.29 g, 3 mmol), and Pd(dppf)Cl2 (22.5 mg, 0.03 mmol) was placed in a round-bottom flask with 10 mL of dioxane. The mixture was heated at 120 °C under nitrogen for 48 hours. After cooling to room temperature, the mixture was washed three times with 50 mL of water and extracted with dichloromethane. The organic solution was dried over Mg2SO4 and then concentrated by rotary evaporation. The crude product was purified by silica gel column chromatography using petroleum ether / dichloromethane (1:20 v / v) as the eluent to give intermediate 13 (0.33 g, 94%) as a white solid.

[0121] A mixture of compounds 13 (0.76 g, 2.2 mmol), 2 (0.30 g, 1 mmol), Pd(PPh3)4 (72 mg, 0.06 mmol), and K2CO3 (0.83 g, 6 mmol) was added to a 50 mL double-necked flask and heated under nitrogen. 20 mL of a mixed solvent system of Toluene / EtOH / H2O (2:1:1, v / v) was injected into the reaction flask, and the reaction mixture was refluxed for 12 h. After cooling to room temperature, the mixture was poured into water and extracted twice with dichloromethane, then dried over anhydrous magnesium sulfate. After filtration, the mixture was concentrated by rotary evaporation. The crude product was purified by silica gel column chromatography using dichloromethane / petroleum ether (1:1, v / v) as the eluent to give a yellow powder 5-31 (0.67 g, 86%).

[0122] Example 8

[0123]

[0124] The synthesis of compound 16 was similar to that in step 2. Compounds 14 (1.15 g, 5 mmol), 15 (1.15 g, 5 mmol), CuI (0.309 g, 1 mmol, 20 mol%), Phen (0.180 g, 1.0 mmol, 20 mol%), and anhydrous Cs₂CO₃ (2.44 g, 7.5 mmol) were added to 10 mL of o-DCB and heated to 180 °C. The mixture was stirred for 24 h under nitrogen protection. After cooling to room temperature, the silica gel column was washed with a large amount of dichloromethane to remove CuI and Cs₂CO₃, and the filtrate was collected. The solvent was then removed by vacuum distillation. The product was then purified by silica gel column chromatography with a dichloromethane / petroleum ether ratio of 1:2 (v / v). The product was concentrated by rotary evaporation to obtain compound 16 (0.140 g, 13%) as a yellow-green powder.

[0125] A mixture of 16 (0.30 g, 1.0 mmol), diphenylamine (0.51 g, 3.0 mmol), Pd2(dba)3 (0.046 g, 0.05 mmol, 5 mol%), S-phos (0.082 g, 0.2 mmol, 20 mol%), and NaOtBu (0.38 g, 4.0 mmol) was heated to 140 °C in 15 mL of Xylenen:DMF (2:1 v / v) co-solvent and heated under a nitrogen stream for 24 h. The reaction mixture was extracted with ethyl acetate upon cooling, dried over anhydrous sodium sulfate, and concentrated by rotary evaporation. The crude product was purified by silica gel column chromatography using ethyl acetate / petroleum ether (1:10 v / v) as eluent to give a white solid 17 (0.36 g, 83%).

[0126] The synthesis of compound 5-39 was similar to that of 5-11. A mixture of 17 (0.44 g, 1.0 mmol), 8 (0.41 g, 1.1 mmol), Pd2(dba)3 (0.046 g, 0.05 mmol, 5 mol%), S-phos (0.082 g, 0.2 mmol, 20 mol%), and NaOtBu (0.38 g, 4.0 mmol) was heated to 140 °C in 60 mL of Xylenen:DMF (2:1 v / v) cosolvent under a nitrogen stream for 24 h. The reaction mixture was extracted with ethyl acetate upon cooling, dried over anhydrous sodium sulfate, and concentrated by rotary evaporation. The crude product was purified by silica gel column chromatography using ethyl acetate / petroleum ether (1:20 v / v) as eluent to give 5-39 (0.69 g, 86%) as a yellow solid.

[0127] Example 9

[0128]

[0129] The synthesis of compound 18 was similar to that in step 2. 14 (1.15 g, 5 mmol), CuI (0.309 g, 1 mmol, 20 mol%), Phen (0.180 g, 1.0 mmol, 20 mol%), and anhydrous Cs₂CO₃ (2.44 g, 7.5 mmol) were added to 10 mL of o-DCB and heated to 180 °C. The mixture was stirred for 24 h under nitrogen protection. After cooling to room temperature, the silica gel column was washed with a large amount of dichloromethane to remove CuI and Cs₂CO₃, and the filtrate was collected. The solvent was then removed by vacuum distillation. The product was then purified by silica gel column chromatography with a dichloromethane / petroleum ether ratio of 1:2 (v / v). The product was concentrated by rotary evaporation to obtain 18 (0.11 g, 12%) as a yellow-green powder.

[0130] The synthesis of compound 5-56 was similar to that of 5-11. A mixture of 18 (0.30 g, 1 mmol), 8 (0.41 g, 1.1 mmol), Pd2(dba)3 (0.046 g, 0.05 mmol, 5 mol%), S-phos (0.082 g, 0.2 mmol, 20 mol%), and NaOtBu (0.38 g, 4.0 mmol) was heated to 140 °C in 15 mL of Xylenen:DMF (2:1 v / v) co-solvent under a nitrogen stream for 24 h. The reaction mixture was extracted with ethyl acetate upon cooling, dried over anhydrous sodium sulfate, and concentrated by rotary evaporation. The crude product was purified by silica gel column chromatography using ethyl acetate / petroleum ether (1:10 v / v) as eluent to give a yellow-green powder 5-56 (0.91 g, 88%).

[0131] Example 10

[0132]

[0133] The synthesis of compound 20 was similar to that of compound 2. 19 (1.15 g, 5 mmol), CuI (0.309 g, 1 mmol, 20 mol%), Phen (0.180 g, 1.0 mmol, 20 mol%), and anhydrous Cs₂CO₃ (2.44 g, 7.5 mmol) were added to 10 mL of o-DCB and heated to 180 °C. The mixture was stirred for 24 h under nitrogen protection. After cooling to room temperature, the silica gel column was washed with a large amount of DCM to remove CuI and Cs₂CO₃, and the filtrate was collected. The solvent was then removed by vacuum distillation. The product was then purified by silica gel column chromatography with a dichloromethane / petroleum ether ratio of 1:3 (volume). The product was concentrated by rotary evaporation to obtain a yellow-green powder, 20 (0.150 g, 13%).

[0134] The synthesis of compound 5-67 was similar to that of 5-11. A mixture of 20 (0.30 g, 1.0 mmol), 8 (0.83 g, 2.2 mmol), Pd2(dba)3 (0.046 g, 0.05 mmol, 5 mol%), S-phos (0.082 g, 0.2 mmol, 20 mol%), and NaOtBu (0.38 g, 4.0 mmol) was heated to 140 °C in 20 mL of Xylenen:DMF (2:1 v / v) cosolvent and heated under a nitrogen stream for 24 h. The reaction mixture was extracted with ethyl acetate upon cooling, dried over anhydrous sodium sulfate, and concentrated by rotary evaporation. The crude product was purified by silica gel column chromatography using ethyl acetate / petroleum ether (1:20 v / v) as eluent to give a yellow solid 5-67 (0.86 g, 84%).

[0135] Examples 20-30

[0136] Examples 20-30 are all organic electroluminescent devices, such as... Figure 1 As shown, the organic electroluminescent device comprises a substrate, and sequentially formed on the substrate an anode layer 10, a hole injection layer 11, a first hole transport layer, a second hole transport layer (the first and second hole transport layers constitute a hole transport layer 12), a light-emitting layer 13, a second electron transport layer 14, a first electron transport layer 15, an electron injection layer 16, and a cathode layer 17. The light-emitting layer contains a pyrrolophenezine nitrogen-containing heterocyclic compound as described in Examples 1-10. This organic electroluminescent device is prepared by the following method:

[0137] A 30mm × 30mm × 0.7mm thick glass substrate with an ITO transparent electrode (i.e., anode layer 10, with an ITO film thickness of 95nm) was sequentially ultrasonically cleaned in acetone, cleaning solution, ultrapure water (3 times), and isopropanol, with each ultrasonic cleaning step lasting 10 minutes. The cleaned ITO glass substrate was then placed in an oven at 100℃ and baked for 3 hours.

[0138] The baked ITO glass substrate was subjected to vacuum plasma cleaning for 10 minutes.

[0139] The plasma-treated glass substrate is mounted on the substrate holder of the vacuum evaporation apparatus. First, HATCN compound is deposited on the side where transparent electrode lines are formed in a manner that covers the transparent electrode to form a hole injection layer 11 with a film thickness of 10 nm.

[0140] Compound HT-10 is vapor-deposited on the hole injection layer 11 to form a first hole transport layer with a film thickness of 65 nm.

[0141] Compound HT-64 is deposited on the first hole transport layer to form a second hole transport layer with a film thickness of 5 nm. The first hole transport layer and the second hole transport layer constitute the hole transport layer 12.

[0142] Subsequently, host material and guest material are co-deposited on the second hole transport layer to form a light-emitting layer 13 with a film thickness of 20 nm. The concentration of guest material in the light-emitting layer is 2% by mass.

[0143] Subsequently, ET-15 is deposited on the light-emitting layer 13 to form a second electron transport layer 14 with a film thickness of 5 nm.

[0144] Subsequently, Liq and ET-9 were co-deposited on the second electron transport layer, with the concentration of Liq set to 30% by mass, to form a first electron transport layer 15 with a film thickness of 25 nm.

[0145] In addition, Liq is deposited on the first electron transport layer to form an electron injection layer 16 with a thickness of 2 nm.

[0146] Then, metal Al is deposited on the electron injection layer to form a cathode layer 17 with a film thickness of 100 nm.

[0147] In the above preparation method, the specific structural formulas of ET-15, HT-10, HT-64, HATCN, Liq, and ET-9 are as follows:

[0148]

[0149] In Examples 20-30, the specific compositions of the main material and the object material are shown in Table 2.

[0150] Table 2

[0151] Example Object material (2% by mass) Main materials 20 5-11 7-9 21 5-12 7-9 22 5-14 7-9 23 5-17 7-9 24 5-22 7-9 25 5-26 7-9 26 5-31 7-9 27 5-39 7-9 28 5-56 7-9 29 5-57 7-9 30 5-22 7-14

[0152] Comparative Examples 40-45

[0153] Comparative Examples 40-45 are organic electroluminescent devices, and their preparation methods are the same as those of Examples 20-30. The difference lies in the different host and guest materials used in the light-emitting layer. The specific guest and host materials used in each comparative example are shown in Table 3.

[0154] Table 3

[0155] Comparative example Object material (2% by mass) Main materials 40 Compare compound 1 7-21 41 Compare compound 2 7-21 42 Compare compound 3 7-21 43 Compare compound 4 7-21 44 Compare compound 5 7-21 45 Compare compound 1 7-14

[0156] Comparative compound 4 and comparative compound 5 have the following structural formulas:

[0157]

[0158] Examples 50-54

[0159] Examples 50-54 are organic electroluminescent devices comprising a combination of a guest material, an auxiliary host material, and a host material as the light-emitting layer. Except for the second hole transport layer, the light-emitting layer, and the second electron transport layer, the device structure of the organic electroluminescent device is the same as that of Examples 20-30.

[0160] The compound HT-76 is deposited on the first hole transport layer to form a second hole transport layer with a film thickness of 10 nm. The first hole transport layer and the second hole transport layer constitute the hole transport layer 12.

[0161] Subsequently, a guest material, an auxiliary host material, and a host material are co-deposited on the second hole transport layer to form a light-emitting layer 13 with a film thickness of 30 nm. The concentration of the guest material in the light-emitting layer is 1% by mass.

[0162] Subsequently, ET-26 is deposited on the light-emitting layer 13 to form a second electron transport layer 14 with a thickness of 10 nm.

[0163] The specific structural formulas of HT-76 and ET-26 in the above preparation method are as follows:

[0164]

[0165] In Examples 50-54, the specific composition of the combination of the guest material, the auxiliary host material, and the host material is shown in Table 4.

[0166] Table 4

[0167] Example Object material (1% by mass) Auxiliary main materials (30% by mass) Main materials 50 5-17 10-31 9-12 51 5-22 10-31 9-12 52 5-39 10-31 9-12 53 5-22 10-18 9-12 54 5-22 10-34 9-12

[0168] Comparative Examples 60–63

[0169] Comparative Examples 60-63 are organic electroluminescent devices, and their preparation methods are the same as those of Examples 50-54. The difference lies in the guest material, auxiliary host material, and host material used in the light-emitting layer. The specific guest material, auxiliary host material, and host material used in each comparative example are shown in Table 5.

[0170] Table 5

[0171] Comparative example Object material (1% by mass) Auxiliary main materials (30% by mass) Main materials 60 Compare compound 1 10-31 9-12 61 Compare compound 2 10-31 9-12 62 Compare compound 3 10-31 9-12 63 Compare compound 1 10-18 9-12

[0172] Performance testing

[0173] The performance of the electroluminescent devices described in Examples 20-30, Comparative Examples 40-45, Examples 50-54, and Comparative Examples 60-63 was tested, and the specific tests are as follows:

[0174] Measurements were taken using a spectroradiometer CS-2000 (Konica Minolta) and a digital source meter 2420 (Keithley), with a current density of 10 mA / cm². 2 The organic electroluminescent device under test was driven to measure its CIE1931 chromaticity coordinates (x,y), external quantum efficiency, emission peak position, and full width at half maximum (FWHM) of the electroluminescence spectrum (in nm).

[0175] The specific test results of Examples 20-30 and Comparative Examples 40-45 are shown in Table 6.

[0176] Table 6

[0177]

[0178] The specific test results of Examples 50-54 and Comparative Examples 60-63 are shown in Table 7.

[0179] Table 7

[0180]

[0181]

[0182] As shown in Table 6, with other materials remaining the same in the organic electroluminescent device structure, the organic electroluminescent devices described in Examples 20-30 have a narrower spectral half-width (HWHM) and higher purity of emitted blue light compared to Comparative Examples 40-45. In particular, compared to Comparative Examples 40 and 42, with the same substituents, Examples 24 and 27 exhibit narrower HWHMs and higher external quantum efficiencies. This may be because the pyrrolophenazine molecular skeleton itself suppresses molecular vibrations and conformational relaxation that lead to spectral broadening, resulting in a smaller HWHM. Furthermore, as shown in Examples 20, 21, and 22, the same substituents at different substitution sites exhibit different HWHMs, possibly because the substituents at certain preferred sites can further suppress molecular stretching vibrations at those sites, thus exhibiting a smaller HWHM. Furthermore, the external quantum efficiencies of the devices in Examples 20-30 are all higher than those of the organic electroluminescent devices described in the comparative compounds under the same device structure. This is because the molecular skeleton of pyrrolophenazine has strong rigidity, which suppresses nonradiative transition vibrations. At the same time, the compound of this application has a large transition dipole, and the material achieves a high fluorescence quantum yield, thus obtaining high-efficiency luminescence characteristics. As can be seen from Examples 24 and 27, under the same substituent, introducing nitrogen atoms into the molecular skeleton of pyrrolophenazine can further enhance the transition dipole strength of the molecule, thereby further improving the luminescence efficiency of the device prepared by the compound.

[0183] Furthermore, Table 7 shows organic electroluminescent devices prepared using guest materials, auxiliary host materials, and host material compositions. The luminous efficiency of the organic electroluminescent devices described in Examples 50-54 is significantly improved compared to Examples 20-30, and is also higher than that of Comparative Examples 60-63, indicating that the luminous efficiency of the guest material is improved with the support of the auxiliary host, and the pyrrolophenazine compound has better luminous performance. On the other hand, the blue light device of the guest material, auxiliary host material, and host material composition scheme still has narrow-spectrum blue light emission characteristics, indicating that the exciton energy of the auxiliary host material has been transferred relatively completely to the guest material.

[0184] The experimental data above show that the novel organic material of this application, as the light-emitting object of organic electroluminescent devices, is a high-performance organic light-emitting functional material and is expected to be promoted for commercial application.

[0185] It is understood that those skilled in the art can make equivalent substitutions or modifications to the technical solution and inventive concept of the present invention, and all such substitutions or modifications should fall within the protection scope of the appended claims.

Claims

1. A pyrrolophenazine nitrogen-containing heterocyclic compound, characterized in that, Its structural formula is as shown in formula (5-39) or (5-56) or (5-57):

2. A luminescent composition, characterized in that, It includes a guest material and a host material; the guest material is a nitrogen-containing heterocyclic compound of pyrrolophenazine as described in claim 1, and the mass percentage of the guest material is 0.3% to 20.0%.

3. The luminescent composition according to claim 2, characterized in that, The host material is selected from the following compounds:

4. The luminescent composition according to claim 2, characterized in that, It also includes an auxiliary host material; the mass percentage of the guest material is 0.3-10.0%, the mass percentage of the host material is 30.0-94.7%, and the mass percentage of the auxiliary host material is 5.0-60.0%; the auxiliary host material is used to improve the luminescence efficiency and exciton utilization efficiency of the guest material.

5. The luminescent composition according to claim 4, characterized in that, The host material is selected from one of the following compounds: The auxiliary host material is selected from one of the following compounds: 。 6. An organic electroluminescent device, comprising: The substrate comprises an anode layer, an organic light-emitting functional layer, and a cathode layer formed on the substrate, wherein the organic light-emitting functional layer includes one or more of a light-emitting layer, a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer, characterized in that the raw material for preparing the light-emitting layer includes the pyrrolophenazine nitrogen-containing heterocyclic compound as described in claim 1, or the raw material for preparing the light-emitting layer is a light-emitting composition as described in any one of claims 2 to 5.

Images