Polycyclic compound and organic electroluminescent device comprising same

Abstract

The invention provides a polycyclic compound and an organic electroluminescent device containing the polycyclic compound, the structural general formula of the polycyclic compound is as shown in the formula I. The energy level difference between the triplet excitation state and the ground state of the polycyclic compound is small, the probability of intersystem crossing from the triplet state to the singlet state can be increased, and the organic electroluminescent device can be used for improving the luminous efficiency of the organic electroluminescent device. And the energy of the triplet excited state is more easily released through a non-radiation process and returns to a ground state. The polycyclic compound is used as a blue dopant to be applied to an organic light-emitting layer of the organic light-emitting device, and the blue dopant can effectively improve the light-emitting efficiency of the organic light-emitting device, prolong the service life of the organic light-emitting device and overcome the defects in the prior art. # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the technical field of OLED, and specifically comprises a polycyclic compound and an organic electroluminescent device comprising the same. Background Art

[0002] Organic Light Emitting Devices (OLED) refers to the phenomenon that organic semiconductor materials emit light through carrier injection, transmission, and recombination under the drive of an electric field. Displays made based on this light-emitting principle are called organic electroluminescent displays. Due to the characteristics of high brightness, good color effects, low driving voltage, low power consumption, low noise, fast response speed, high luminous efficiency, and easy full-colorization, organic electroluminescent displays have attracted many internationally renowned companies to invest heavily in research and development.

[0003] Under the condition of electrical excitation, holes and electrons are injected from the anode and cathode respectively. When the two are combined in the light-emitting layer to produce excitons, according to spin statistics, the ratio of singlet and triplet excitons in the excitons is 1:3. The excitons in the singlet state decay from the S1 state to the ground state S0 in the form of radiation. The luminescence generated by this process is called fluorescence. The triplet excitons directly decay from the T1 state to the ground state S0, and the luminescence generated by radiation decay is called phosphorescence. The ground state of organic molecules is usually singlet. The spin multiplicity of electrons in the fluorescence process does not change, and the transition is allowed. However, the phosphorescence process is transition-forbidden due to the change in the spin multiplicity of electrons. Therefore, triplet excitons cannot release energy quickly through the radiation process. If the material is in an excited state for a long time, it is easy to cause the material itself to decompose, thereby affecting the life of the organic electroluminescent device.

[0004] For full-color display applications, it is necessary for the three colors RGB to have high brightness efficiency, balanced stable chromaticity and luminescence stability. The general three-color light-emitting device settings are all realized through the host-guest doping luminescence mechanism, which uses a single host or co-doped host material to dope with a fluorescent or phosphorescent guest material to achieve electroluminescence. Through the combination of suitable host materials and phosphorescent guest materials, great progress has been made in achieving high-efficiency and high-purity red and green light emission, which is no longer the main problem of OLED today. However, the luminous brightness, efficiency, lifespan and other properties of blue light OLEDs need to be improved. It is urgent to develop a blue fluorescent organic electroluminescent material with high luminous efficiency and long life. Summary of the invention

[0005] In view of this, the present invention provides a polycyclic compound and an organic electroluminescent device comprising the same. The energy level difference between the triplet excited state and the ground state of the polycyclic compound is small, and the probability of intersystem crossing from the triplet state to the singlet state can be increased, so that the energy of the triplet excited state is more easily released through a non-radiative process and returns to the ground state. The polycyclic compound is applied as a blue dopant in an organic light-emitting layer of an organic electroluminescent device. The blue dopant can effectively improve the luminous efficiency of the organic electroluminescent device and prolong the life of the organic electroluminescent device, thereby overcoming the defects of the prior art.

[0006] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical scheme: In the first aspect of the present invention, a polycyclic compound is provided, and the general structural formula of the compound is shown in Formula I:

[0007]

[0008] in,

[0009] R1 is selected from any one or any combination of hydrogen, deuterium, and a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms;

[0010] R2 is selected from any one or any combination of hydrogen, deuterium, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted condensed ring aryl group having 10 to 30 carbon atoms, and a substituted or unsubstituted arylamine group having 18 to 30 carbon atoms;

[0011] R3 is selected from any one or any combination of hydrogen, deuterium, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted alkylamine group having 2 to 10 carbon atoms, and a substituted or unsubstituted arylamine group having 18 to 30 carbon atoms;

[0012] Ar1 and Ar2 are selected from any one or any combination of substituted or unsubstituted alkyl groups having 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 30 carbon atoms, and substituted or unsubstituted aryl groups having 6 to 30 carbon atoms, and one of Ar1 and Ar2 is selected from the structure shown in Formula II:

[0013]

[0014] The L1 is selected from any one or any combination of phenyl, biphenyl, cyclohexyl, and dimethylfluorenyl;

[0015] Ar3 is selected from any one or any combination of hydrogen, deuterium, tert-butyl, phenyl, naphthyl, cyclohexyl, 1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthyl;

[0016] When any one of R1, R2, R3, Ar1, and Ar2 has a substituent, the substituent of R1, R2, R3, Ar1, and Ar2 may be one or more, and each is independently selected from any one of deuterium, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, and an aryl group having 6 to 30 carbon atoms, wherein two or more substituents may be bonded to each other through a linking group or a single bond to form an aliphatic ring or an aromatic ring;

[0017] Any hydrogen in the polycyclic compound represented by formula I can be independently replaced by deuterium.

[0018] In combination with the first aspect, the R1 is selected from any one or a combination of any two of hydrogen, deuterium, and tert-butyl.

[0019] In combination with the first aspect, R2 is selected from any one or a combination of any two of tert-butyl, substituted or unsubstituted phenyl, substituted or unsubstituted diphenylamino, and 1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthyl.

[0020] In combination with the first aspect, R3 is selected from any one of hydrogen, deuterium, methyl, tert-butyl, cyclohexane, substituted or unsubstituted phenyl, substituted or unsubstituted diphenylamino, dimethylamino, and 1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthyl.

[0021] In combination with the first aspect, the compound represented by formula I is selected from any one of the structures represented by formula I-1 to formula I-2 below:

[0022]

[0023]

[0024] Any hydrogen in the polycyclic compounds represented by Formula I-1 to Formula I-24 can be independently replaced by deuterium.

[0025] In combination with the first aspect, the structure represented by formula II is selected from any one of the structures represented by formula II-1 to formula II-17 below:

[0026]

[0027] Any hydrogen in the structures represented by Formula II-1 to Formula II-17 can be independently replaced by deuterium.

[0028] In combination with the first aspect, the compound represented by formula I is selected from any one of the following compounds:

[0029]

[0030]

[0031]

[0032]

[0033] The second aspect of the present invention provides the use of the above-mentioned polycyclic compound in the field of organic electroluminescence.

[0034] The third aspect of the present invention provides an organic electroluminescent device, comprising an anode, a hole transport region, a light-emitting layer, an electron transport region and a cathode arranged in sequence on a substrate; wherein the light-emitting layer comprises a main material and a doping material, and the doping material comprises one or more polycyclic compounds as provided in the first aspect of the present invention.

[0035] The beneficial effects of the present invention are as follows:

[0036] The invention provides a polycyclic compound. The sulfur atom in the benzothiophene structure in the polycyclic compound has a heavy atom effect, which can enhance the spin-orbit coupling of the molecule and increase the probability of intersystem crossing from a triplet state to a singlet state. The anthracene structure in the polycyclic compound has good planar conjugation, which makes the electrons on the anthracene fully delocalized, thus significantly reducing the triplet excited state energy, making it easier to release the triplet excited state energy through a non-radiative process and return to a ground state. The polycyclic compound provided by the invention is used as a blue dopant in an organic light-emitting layer of a blue light organic electroluminescent device. Since the polycyclic compound provided by the invention can increase the probability of intersystem crossing from a triplet state to a singlet state, the luminous efficiency of the organic electroluminescent device can be improved. The polycyclic compound provided by the invention can reduce the energy level difference between the triplet excited state and the ground state of the material, making it easier to release the triplet excited state energy through a non-radiative process and return to the ground state, and will not be in an excited state for a long time, causing the decomposition of the material itself, thereby improving the life of the organic electroluminescent device, and overcoming the defects of the prior art. Description of the drawings:

[0037] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0038] Figure 1 is a schematic structural diagram of an organic electroluminescent device containing the compound of the present invention;

[0039] Description of the drawings: 1-substrate, 2-anode, 3-hole injection layer, 4-hole transport layer, 5-luminescence auxiliary layer, 6-luminescent layer, 7-electron transport layer 1, 8-electron transport layer 2, 9-electron injection layer, 10-cathode. DETAILED DESCRIPTION

[0040] In order to more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments and accompanying drawings. Similar components in the accompanying drawings are represented by the same figure numerals. It should be understood by those skilled in the art that the content specifically described below is illustrative and not restrictive, and the protection scope of the present invention should not be limited to this. The embodiments and comparative examples of this specification are provided to more completely explain this specification to those skilled in the art. According to the embodiments and comparative examples of this specification, various different forms can be deformed, and the protection scope of the present invention should not be limited only to the embodiments and comparative examples described in detail below.

[0041] The compounds of the present invention are suitable for use in light-emitting elements, display panels and electronic devices, and are particularly suitable for use in organic electroluminescent devices. The electronic device of the present invention is a device comprising a layer of at least one organic compound, which may also comprise an inorganic material or a layer formed entirely of an inorganic material. The electronic device is preferably an organic electroluminescent device (OLED), an organic integrated circuit (O-IC), an organic field effect transistor (O-FET), an organic thin film transistor (O-TFT), an organic light emitting transistor (O-LET), an organic solar cell (O-SC), an organic dye-sensitized solar cell (O-DSSC), an organic optical detector, an organic photoreceptor, an organic field quenching device (O-FQD), a light-emitting electrochemical cell (LEC), an organic laser diode (O-laser) and an organic plasma emission device. The electronic device is preferably an organic electroluminescent device (OLED).

[0042] In order to understand the content of the present invention more clearly, the polycyclic compound containing triarylamine structure, the preparation method of the compound and the luminescent characteristics of the device will be explained in detail in conjunction with the examples. Various chemical reactions can be applied to the synthesis method of the compound of one embodiment of the present invention. However, it should be noted that the synthesis method of the compound of one embodiment of the present invention is not limited to the synthesis method described below. Unless otherwise specified, the subsequent synthesis is carried out in anhydrous solvent under a protective gas atmosphere. Solvents and reagents can be purchased from conventional reagent suppliers. The compound of the present invention is prepared by using a representative reaction Buchwald-Hartwig coupling reaction, Suzuki coupling reaction or Heck coupling reaction.

[0043] Intermediate synthesis

[0044]

[0045] The general formula for the synthesis of the intermediate is as above. The target intermediate can be obtained by a two-step common Buchwald-Hartwig coupling synthesis method. The specific case is as follows:

[0046] Intermediate Example 1

[0047]

[0048] Sub1 (54.9 g; 100 mmol), Sub2 (34.5 g; 100 mmol) and sodium tert-butoxide (105 g, 110 mmol) were added to toluene (500 ml), and then bis(dibenzylideneacetonepalladium) (2.7 g, 3.0 mmol) and tri-tert-butylphosphine (1.2 g, 6.0 mmol) were introduced under nitrogen protection, and then the reaction system was heated to 110°C and maintained for 10 hours, and then water was added to quench the reaction after cooling to room temperature, and the organic phase was separated and reacted to obtain an organic phase, which was filtered and dried over anhydrous sodium sulfate, the solvent was removed by rotation, and the crude product was purified by column chromatography. Finally, the product Sub3 was obtained: 72.3 g (yield: 89%), MS (m / z) (M+): 813.2.

[0049] Sub3 (72.3 g; 89 mmol), Sub4 (30.1 g; 89 mmol) and sodium tert-butoxide (86.6 g, 90 mmol) were added to toluene (500 ml), and then bis(dibenzylideneacetonepalladium) (2.5 g, 2.7 mmol) and 5-bis(diphenylphosphine)-9,9-dimethylxanthene (3.0 g, 5.4 mmol) were introduced under nitrogen protection. The reaction system was then heated to 110° C. and maintained for 10 hours. After cooling to room temperature, water was added to quench the reaction, and the organic phase was separated. The organic phase was filtered and dried over anhydrous sodium sulfate. The solvent was removed by rotation, and the crude product was purified by column chromatography to obtain product A1: 56.2 g (yield: 61.7%), MS (m / z) (M+): 1024.3.

[0050] After intermediate A1 is obtained through the above process, other intermediates A2 to A13 can be obtained by using a method that is basically the same as the method for synthesizing intermediate A1, except that the reactants are different.

[0051] Compound Example 1

[0052] This embodiment provides a compound B1, and the synthesis route of the compound is as follows:

[0053]

[0054] Under nitrogen protection, the system was maintained at -30°C to -40°C, and n-butyllithium solution (15.40 mL, 20.00 mmol) was slowly added dropwise to a solution of A1 (10.24 g, 10 mmol) in tert-butylbenzene (100 mL), followed by heating to 60°C and stirring for 6 hours; the temperature was lowered to -30°C, boron tribromide (1.91 mL, 20.00 mmol) was added dropwise, the temperature was raised to 60°C and stirred for 6 hours; the temperature was lowered to 0°C, N,N-diisopropylethylamine (2.78 mL, 20.0 0mmol), the reaction system was heated to room temperature 25°C and stirred for 2 hours; 150mL of deionized water was added to the reaction system, the mixture was extracted with 200mL of dichloromethane, the organic layers were combined, and the crude product was concentrated in vacuo to obtain the crude product, the crude product was separated and purified by column chromatography (the mobile phase of the column chromatography was dichloromethane: petroleum ether = 1:20) to obtain a purified product, the purified product was recrystallized from n-heptane, acetone and toluene, and finally the product B1 was obtained: 0.49g, yield: 5.2%, MS (m / z) (M+): 953.2.

[0055] Compound Example 2

[0056] This embodiment provides a compound B2, the synthesis route of which is as follows:

[0057]

[0058] The method is the same as Example 1, except that an equimolar amount of A2 (11.00 g; 10 mmol) is used to replace A1, and finally the product B2 is obtained: 0.54 g (yield: 5.2%), MS (m / z) (M+): 1029.3.

[0059] Compound Example 3

[0060] This embodiment provides a compound B3, the synthesis route of which is as follows:

[0061]

[0062] The method is the same as Example 1, except that an equimolar amount of A3 (11.55 g; 10 mmol) is used to replace A1, and finally the product B3 is obtained: 0.54 g (yield: 5.0%), MS (m / z) (M+): 1084.2.

[0063] Compound Example 4

[0064] This embodiment provides a compound B4, the synthesis route of which is as follows:

[0065]

[0066] The method is the same as Example 1, except that an equimolar amount of A4 (12.09 g; 10 mmol) is used to replace A1, and the final product B4 is obtained: 0.72 g (yield: 6.3%), MS (m / z) (M+): 1140.4.

[0067] Compound Example 5

[0068] This example provides a compound B5, the synthesis route of which is as follows:

[0069]

[0070] The method is the same as Example 1, except that an equimolar amount of A5 (11.55 g; 10 mmol) is used to replace A1, and finally the product B5 is obtained: 0.47 g (yield: 4.3%), MS (m / z) (M+): 1084.2.

[0071] Compound Example 6

[0072] This example provides a compound B6, the synthesis route of which is as follows:

[0073]

[0074] The method is the same as Example 1, except that an equimolar amount of A6 (11.55 g; 10 mmol) is used to replace A1, and finally the product B6 is obtained: 0.79 g (yield: 7.3%), MS (m / z) (M+): 1084.2.

[0075] Compound Example 7

[0076] This example provides a compound B7, the synthesis route of which is as follows:

[0077]

[0078] The method is the same as Example 1, except that an equimolar amount of A7 (12.716 g; 10 mmol) is used to replace A1, and the final product B7 is obtained: 0.86 g (yield: 7.1%), MS (m / z) (M+): 1200.5.

[0079] Compound Example 8

[0080] This example provides a compound B8, the synthesis route of which is as follows:

[0081]

[0082] The method is the same as Example 1, except that an equimolar amount of A8 (12.65 g; 10 mmol) is used to replace A1, and finally the product B8 is obtained: 0.60 g (yield: 5.0%), MS (m / z) (M+): 1194.4.

[0083] Compound Example 9

[0084] This example provides a compound B9, the synthesis route of which is as follows:

[0085]

[0086] The method is the same as Example 1, except that an equimolar amount of A9 (12.93 g; 10 mmol) is used to replace A1, and the final product B9 is 0.75 g (yield: 6.1%), MS (m / z) (M+): 1222.5.

[0087] Compound Example 10

[0088] This example provides a compound B10, the synthesis route of which is as follows:

[0089]

[0090] The method is the same as Example 1, except that an equimolar amount of A10 (12.87 g; 10 mmol) is used to replace A1, and finally the product B10 is obtained: 0.96 g (yield: 7.9%), MS (m / z) (M+): 1216.5.

[0091] Compound Comparative Example 1

[0092] This comparative example provides a compound BD1 that has been tested during the research process, and its specific structural formula is:

[0093]

[0094] Compound Comparative Example 2

[0095] This comparative example provides a compound BD2 that has been tested during the research process, and its specific structural formula is:

[0096]

[0097] Effect example

[0098] Fluorescence and phosphorescence are the two main types of luminescence in OLEDs. Both of these radiation transition processes end at the ground state S0. The initial excited state of fluorescence is the singlet state, and the initial excited state of phosphorescence is the triplet state. According to the Frank Condon principle, when external energy excites the fluorescent molecules in the ground state, the luminescent molecules absorb energy, causing the electrons in them to transition to a higher energy level S0. n Part of the energy will be dissipated in non-radiative ways such as Joule heat, and the molecule relaxes from the vibrational excited state to the lowest vibrational state S1, i.e. the initial excited state. According to the principle of minimum energy, the molecule in this unstable state eventually returns to the ground state S0 through molecular vibration. The light emitted by the radiative transition and radiative decay in the process is called fluorescence. If the molecule is excited by energy, it transitions from the ground state to the triplet energy level T1, and then returns to the ground state S0 from the T1 energy level through molecular vibration, emitting phosphorescence in the process accompanied by the energy dissipation of the non-radiative process, which is called phosphorescence emission.

[0099] HORIBA FluoroLog-3 was used to perform a temperature-dependent steady-state transient fluorescence spectrometer test. 7.5 mg of B1 to B10 provided in Examples 1 to 10 and BD1 and BD2 provided in Comparative Examples 1 to 2 were respectively dissolved in toluene to a concentration of 1 to 2×10 -6 g / mL solution, the phosphorescence spectrum of the tested sample was tested at 77K, the wavelength was obtained through the phosphorescence spectrum, and the triplet excited state energy of the material was calculated by the formula: energy = 1240 / wavelength (the unit of energy is eV, and the unit of wavelength is nm). The specific calculation results are shown in Table 1:

[0100] Table 1 Triplet excited state energy of compounds

[0101]

[0102]

[0103] From the calculation results of Table 1 above, it can be seen that compared with the comparative example compounds, the triplet energy of the polycyclic compounds provided by the present invention is significantly lower. Compared with the comparative example BD1, the compounds B1 to B10 provided by the present invention can significantly reduce the triplet excited state energy by adding an anthracene structure at the 2nd or 4th position; compared with the comparative example BD2, the compounds B1 to B10 provided by the present invention can enhance the spin-orbit coupling of the molecule by adding a benzothiophene structure, increase the probability of intersystem crossing from the triplet state to the singlet state, and thus reduce the triplet excited state energy. Therefore, the polycyclic compounds provided by the present invention are more likely to release the energy of the triplet excited state back to the ground state S0 through a non-radiative process.

[0104]

[0105] Device Embodiment

[0106] The organic electroluminescent device of the following embodiment includes an anode 2, a hole transport region, a light-emitting layer 5, an electron transport region, and a cathode 8 arranged in sequence on a substrate 1; wherein: the hole transport region includes a hole transport layer 3 and a light-emitting auxiliary layer 4; the electron transport region includes an electron transport layer 6 and an electron injection layer 7; the light-emitting layer 5 is composed of a host and a doped guest, and the host of the light-emitting layer can be composed of one molecular material or multiple molecular materials. The typical structure of an organic electroluminescent device is as follows Figure 1 shown.

[0107] The anode of the following embodiments adopts anode materials commonly used in the art, such as ITO, Ag or their multilayer structures. The hole injection unit adopts hole injection materials commonly used in the art, and F4TCNQ, HATCN, NDP-9, etc. are added for doping. The hole transport unit adopts hole transport materials commonly used in the art. The light-emitting unit adopts light-emitting materials commonly used in the art, for example, it can be composed of a host material and an emitted guest material doped, and the emitted guest material can be an organic material such as a pyrene compound, or it can be a metal complex (such as metal Ir, Pt, etc.). The electron transport unit adopts electron transport materials commonly used in the art. The electron injection layer adopts electron injection materials commonly used in the art, such as Liq, LiF, Yb, etc. The cathode adopts materials commonly used in the art, such as metal Al, Ag or metal mixtures (Ag-doped Mg, Ag-doped Ca, etc.).

[0108] The electrode preparation methods and the deposition methods of each functional layer in the following embodiments are conventional methods in the art, such as vacuum thermal evaporation or inkjet printing, etc., which will not be described in detail here. Only some process details and test methods in the preparation process are supplemented as follows:

[0109] Device Example 1

[0110] The present embodiment provides a blue light organic electroluminescent device, and the preparation method thereof is as follows: first, on the ITO layer (anode) formed on the substrate, HTL-1 and F4TCNQ (the mass ratio of HTL-1 to F4TCNQ is 97:3) are vacuum deposited with a thickness of 10 nm to form a hole injection layer; secondly, on the hole injection layer, HTL-1 is vacuum deposited with a thickness of 120 nm to form a hole transport layer; secondly, on the hole transport layer, HTL-2 is vacuum deposited with a thickness of 10 nm to form a light-emitting auxiliary layer; thirdly, on the light-emitting auxiliary layer, a mixture of BH and compound B1 provided in compound embodiment 1 is vacuum deposited with a thickness of 20 nm. A light-emitting layer is formed by vacuum depositing ET-01 with a thickness of 5 nm on the light-emitting layer to form an electron transport layer 1, and ET-02 and Liq (the mass ratio of ET-02 to Liq is 1:1) are vacuum deposited with a thickness of 30 nm to form an electron transport layer 2; then, LiF is deposited with a thickness of 0.2 nm on the electron transport layer to form an electron injection layer, and finally, aluminum (Al) is deposited with a thickness of 150 nm on the electron injection layer to form a cathode, thereby preparing a blue light-emitting organic electroluminescent device.

[0111] Except for the blue light doping material, the molecular structures of the remaining layers of materials are as follows:

[0112]

[0113] Device Examples 2-10

[0114] This embodiment provides a blue light organic electroluminescent device, and its preparation method is: the compound B1 in the device embodiment 1 is replaced by the compounds B2 to B10 provided in the compound embodiments 2 to 10 to form a light-emitting layer, and the other preparation steps are the same as those of the device embodiment 1, and the blue light organic electroluminescent devices are prepared respectively.

[0115] Device Comparison Example 1-2

[0116] The method is the same as that of device example 1, except that compound B1 in device example 1 is replaced by compounds BD1 and BD2 provided in compound comparison examples 1 to 2 to form a light-emitting layer, and the other preparation steps are the same as those of device example 1, and blue light organic electroluminescent devices are prepared respectively.

[0117] Performance evaluation of organic electroluminescent devices

[0118] The organic electroluminescent devices provided in device examples 1-10 and device comparative examples 1-2 were tested by standard methods. 2The driving voltage, brightness, electroluminescent current efficiency (measured in cd / A) and external quantum efficiency (EQE, measured in percentage) of the organic electroluminescent device are determined at a current density of 500 mA / cm2, which are calculated from a current / voltage / luminescent density characteristic line (IVL characteristic line) showing Lambertian emission characteristics as a function of luminous density. The lifetime LT is defined as the time after which the brightness drops from the initial luminous brightness L0 to a specific proportion L1 when operating at a constant current J; J = 50 mA / cm2 2 The expression L1 = 90% means that at 50 mA / cm 2 When working under LT, the luminance drops to 90% of its initial value L0 after time LT. Similarly, J = 20 mA / cm 2 , L1 = 80% means, at 20mA / cm 2 When the device is operated at a current density of 10 mA / cm 2 The life (LT95) in Table 2 refers to the device under 20mA / cm 2 When working under , the time required for the luminance to drop to 95% of its initial value L0. The external quantum efficiency (EQE) in Table 2 represents the percentage of the total number of photons emitted by the device to the injected carriers.

[0119] Various parameters of the embodiments are compared with those of the comparative examples, and performance data of various OLED devices are shown.

[0120] The test instruments and methods for testing the performance of the OLED devices in the above embodiments and comparative examples are as follows:

[0121] Brightness was tested using a spectral scanner PhotoResearch PR-635;

[0122] Current density and lighting voltage: tested using a digital source meter Keithley 2400;

[0123] Life test: Use LT-96ch life test device.

[0124] The performance test results of the above devices are listed in Table 2.

[0125] Table 2 Blue light device performance test results

[0126]

[0127] It can be seen from the device performance test results in Table 2 that, compared with the comparative compounds BD1 and BD2, the luminous efficiency of the organic electroluminescent device using the polycyclic compound provided by the present invention as the blue light doping material is significantly improved, the driving voltage is significantly reduced, and it also has a certain life advantage. This is because the polycyclic compound provided by the present invention can increase the probability of intersystem crossing from the triplet state to the singlet state, thereby improving the luminous efficiency of the organic electroluminescent device, and the polycyclic compound provided by the present invention can reduce the energy level difference between the triplet excited state and the ground state of the material, so that the energy of the triplet excited state is more easily released through a non-radiative process and returns to the ground state, and will not be in the excited state for a long time, causing the decomposition of the material itself, thereby improving the life of the organic electroluminescent device; thus, it is shown that the polycyclic compound provided by the present invention solves the technical problems of the limitations of the blue light doping materials of the current organic electroluminescent device in terms of luminous efficiency and service life. In addition, the organic electroluminescent device using the polycyclic compound provided by the present invention as a blue light dopant also has the advantages of higher light stability, stronger brightness and better color saturation, which can meet the needs of future high-performance display devices and has important application prospects. This shows that the polycyclic compound provided by the present invention is a blue dopant material with good performance, can meet the performance requirements of blue organic electroluminescent devices, and has practical value.

[0128] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A polycyclic compound, characterized in that The general structural formula of the compound is shown in Formula I: in, R1 is selected from any one or any combination of hydrogen, deuterium, and a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms; R2 is selected from any one or any combination of hydrogen, deuterium, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted condensed ring aryl group having 10 to 30 carbon atoms, and a substituted or unsubstituted arylamine group having 18 to 30 carbon atoms; R3 is selected from any one or any combination of hydrogen, deuterium, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted alkylamine group having 2 to 10 carbon atoms, and a substituted or unsubstituted arylamine group having 18 to 30 carbon atoms; Ar1 and Ar2 are selected from any one or any combination of substituted or unsubstituted alkyl groups having 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 30 carbon atoms, and substituted or unsubstituted aryl groups having 6 to 30 carbon atoms, and one of Ar1 and Ar2 is selected from the structure shown in Formula II: The L1 is selected from any one or any combination of phenyl, biphenyl, cyclohexyl, and dimethylfluorenyl; Ar3 is selected from any one or any combination of hydrogen, deuterium, tert-butyl, phenyl, naphthyl, cyclohexyl, 1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthyl; When any one of R1, R2, R3, Ar1, and Ar2 has a substituent, the substituent of R1, R2, R3, Ar1, and Ar2 may be one or more, and each is independently selected from any one of deuterium, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, and an aryl group having 6 to 30 carbon atoms, wherein two or more substituents may be bonded to each other through a linking group or a single bond to form an aliphatic ring or an aromatic ring; Any hydrogen in the polycyclic compound represented by formula I can be independently replaced by deuterium.

2. The polycyclic compound according to claim 1, characterized in that The R1 is selected from any one of hydrogen, deuterium, and tert-butyl, or a combination of any two thereof.

3. The polycyclic compound according to claim 1, characterized in that The R2 is selected from any one or a combination of any two of tert-butyl, substituted or unsubstituted phenyl, substituted or unsubstituted diphenylamino, and 1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthyl.

4. The polycyclic compound according to claim 1, characterized in that The R3 is selected from any one of hydrogen, deuterium, methyl, tert-butyl, cyclohexane, substituted or unsubstituted phenyl, substituted or unsubstituted diphenylamino, dimethylamino, and 1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthyl.

5. The polycyclic compound according to claim 1, characterized in that The compound represented by formula I is selected from any one of the structures represented by the following formula I-1 to formula I-2: Any hydrogen in the polycyclic compounds represented by Formula I-1 to Formula I-24 can be independently replaced by deuterium.

6. The polycyclic compound according to claim 1, characterized in that The structure represented by Formula II is selected from any one of the structures represented by Formula II-1 to Formula II-17 below: Any hydrogen in the structures represented by Formula II-1 to Formula II-17 can be independently replaced by deuterium.

7. The polycyclic compound according to claim 1, characterized in that The compound represented by formula I is selected from any one of the following compounds:

8. The polycyclic compound according to any one of claims 1 to 7, characterized in that The polycyclic compound is applied in the field of organic electroluminescence.

9. An organic electroluminescent device, characterized in that: It includes an anode, a hole transport region, a light-emitting layer, an electron transport region and a cathode arranged in sequence on a substrate; wherein the light-emitting layer includes a main material and a doping material, and the doping material includes one or more polycyclic compounds as described in any one of claims 1 to 7.

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