Helicene type organic compound and application thereof

Abstract

The invention relates to a helicene type organic compound and application thereof, and belongs to the field of organic luminescent materials. The spiral chirality of molecules is regulated and controlled by constructing a rigid framework with ortho-position double boron, so that circularly polarized light emission is realized on the premise of ensuring narrow-band light emission. An organic electroluminescent device prepared by using the ortho-position double-boron structure prepared by the method as a luminescent material not only shows excellent electroluminescent performance, but also shows narrow-band circular polarization luminescent performance, and has huge application value in the fields of ultra-high-definition display, 3D display and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electroluminescent materials, and particularly to a kind of MR-TADF material based on adjacent double boron skeleton helicene type organic compound and application thereof. BACKGROUND

[0002] With the gradual maturity of organic light-emitting diode (OLED) technology, the research on new organic light-emitting materials has also gradually deepened, especially the materials that can have efficiency, stability and color quality, which need to be further explored. The thermally activated delayed fluorescence material can convert the triplet excitons of non-radiative transition into luminescent singlet excitons through the reverse intersystem crossing process, and realize effective light emission, thereby obtaining 100% exciton utilization. The discovery of the thermally activated delayed fluorescence (TADF) mechanism provides a new development direction for improving the light-emitting efficiency of OLED. TADF materials are a kind of pure organic light-emitting materials with broad prospects in OLED and other optoelectronic applications. In order to improve the color purity of OLED devices, developing TADF materials with narrow spectral band light-emitting characteristics has become the most popular research direction at present. The multiple resonance effect (MR) induced thermally activated delayed fluorescence (MR-TADF) material effectively suppresses the vibration coupling and structural relaxation through the alternating highest occupied orbital (HOMO) and lowest unoccupied orbital (LUMO), thereby obtaining a smaller full width at half maximum (FWHM), and the intramolecular short-range charge transfer promotes the molecule to still have TADF characteristics.

[0003] In recent years, with the development of 3D technology, chiral TADF materials have been used to prepare organic light-emitting diodes, which has become a new way for the development of TADF materials. The introduction of chirality into traditional TADF materials prepares TADF materials with circularly polarized light-emitting characteristics, which uses the characteristics of chiral molecules to control the light-emitting process, which has important application value in the fields of optical communication, 3D display and biological imaging. Chiral materials usually have chiral centers or chiral structures, which enable them to emit light with a specific polarization direction, i.e. left-handed or right-handed circularly polarized light. Their chirality can come from the point chirality, axial chirality, planar chirality or helical chirality of the molecule. With the development of circularly polarized thermally activated delayed fluorescence materials, how to develop high-performance light-emitting materials with both circularly polarized properties and narrow spectral band light-emitting characteristics has become a problem that needs to be solved at present. SUMMARY

[0004] The purpose of the present application is to provide a kind of MR-TADF material based on adjacent double boron skeleton helicene type, to solve the problem that there is currently a lack of high-performance light-emitting materials with both circularly polarized properties and narrow spectral band light-emitting characteristics.

[0005] In the product structure designed in the application, a chiral TADF molecule is constructed with a spiroolefin skeleton with ortho-bisboron, so as to simultaneously realize narrow spectral band and circularly polarized light emission characteristics. The prepared spiroolefin type MR-TADF material provides a new design idea for the construction of a chiral TADF molecule.

[0006] To achieve the purpose of the application, the application adopts the following technical solutions:

[0007] In a first aspect of the application, a spiroolefin type organic compound based on an ortho-bisboron skeleton is provided, wherein the spiroolefin type organic compound has the following general formula I structure:

[0008]

[0009] wherein R1-R7 are the same or different, and are independently selected from H, deuterium, halogen, cyano, nitro, amino, substituted or unsubstituted C1-C6 alkyl, C1-C6 alkoxy, C3-C6 cycloalkyl, C6-C10 aryl, and 5- to 18- membered heteroaryl, substituted or unsubstituted diarylamino, substituted or unsubstituted diheteroarylamino, and substituted or unsubstituted arylheteroarylamino. l -C 36 alkyl, C l -C 36 alkoxy, C3-C 36 cycloalkyl, C6-C 30 aryl, and 5- to 18- membered heteroaryl; 30 substituted or unsubstituted diarylamino, substituted or unsubstituted diheteroarylamino, and substituted or unsubstituted arylheteroarylamino.

[0010] X1, X2, Y1, Y2 are the same or different, and are independently selected from O, NR, S, Se, Te, sulfone group, sulfoxide group, wherein R is the same or different, and is independently selected from H, deuterium, halogen, cyano, nitro, amino, substituted or unsubstituted C1-C6 alkyl, C1-C6 alkoxy, C3-C6 cycloalkyl, C6-C10 aryl, and 5- to 18- membered heteroaryl, substituted or unsubstituted diarylamino, substituted or unsubstituted diheteroarylamino, and substituted or unsubstituted arylheteroarylamino. l -C 36 alkyl, C l -C 36 alkoxy, C3-C 36 cycloalkyl, C6-C 30 aryl, and 5- to 18- membered heteroaryl; 30 substituted or unsubstituted diarylamino, substituted or unsubstituted diheteroarylamino, and substituted or unsubstituted arylheteroarylamino.

[0011] The alkyl, alkoxy, cycloalkyl, aryl, and heteroaryl are optionally substituted with one or more substituents selected from halogen, -CN, C1-C6 alkyl, C1-C6 alkoxy, C2-C6 alkenyl, C2-C6 alkynyl, C3-C6 cycloalkyl, C6-C10 aryl, and 5- to 18- membered heteroaryl. 12 alkyl, C1-C 12 alkoxy, C1-C 12 haloalkyl, C2-C6 alkenyl, C3-C6 cycloalkyl, C6-C10 aryl, and 5- to 18- membered heteroaryl. 10 cycloalkyl, C6-C 14 aryl, and 5- to 18- membered heteroaryl.

[0012] Optionally, R1-R7 are the same or different, and each is independently selected from the group consisting of hydrogen, cyano, C1-C4 alkyl, adamantyl, phenyl, cyanophenyl, naphthyl, anthryl, benzanthryl, phenanthryl, furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, thienyl, benzothienyl, isobenzothienyl, dibenzothienyl, pyrrolyl, isoindolyl, carbazolyl, indenocarbazolyl, pyridyl, quinolyl, isoquinolyl, diphenylamino, dinaphthylamino;

[0013] or two adjacent ones of R1-R7 are joined to each other to form a substituted or unsubstituted C6-C 30 aryl, and Ra is selected from the group consisting of cyano, C1-C4 alkyl, adamantyl, phenyl, naphthyl, anthryl, benzanthryl, phenanthryl, furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, thienyl, benzothienyl, isobenzothienyl, dibenzothienyl, pyrrolyl, isoindolyl, carbazolyl, indenocarbazolyl, pyridyl, quinolyl, isoquinolyl, diphenylamino, dinaphthylamino.

[0014] Optionally, the spiro-olene type organic compound is any one of the following compounds:

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

[0021] In a second aspect of the present application, there is provided a use of the spiro-olene type organic compound based on an ortho-bis-boron skeleton according to the present application, wherein the spiro-olene type organic compound based on an ortho-bis-boron skeleton is used as a multiple resonance type thermally activated delayed fluorescence material for preparing an organic electroluminescent device.

[0022] Optionally, the organic electroluminescent device is a circularly polarized organic electroluminescent device.

[0023] In a third aspect of the present application, there is provided an organic electroluminescent device, comprising an organic light-emitting layer, wherein the organic light-emitting layer comprises a host material and a guest material, and the guest material is a spiro-olene type organic compound based on an ortho-bis-boron skeleton according to the present application.

[0024] Optionally, the guest material accounts for 1wt%-5wt% of the total mass of the host material and the guest material, such as 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, etc.

[0025] Optionally, the organic electroluminescent device comprises a substrate, an anode, a cathode, and an organic light-emitting layer between the anode and the cathode.

[0026] Optionally, the organic electroluminescent device comprises a substrate, and an anode, a hole injection layer, a hole transport layer, an electron blocking layer, an organic light-emitting layer, an electron transport layer, an electron injection layer, and a cathode plated on the substrate.

[0027] Optionally, ITO is the material of the anode; HI is the material of the hole injection layer; HT is the material of the hole transport layer; EBL is the material of the electron blocking layer; Host is the host material of the organic light-emitting layer with a wide band gap, and the organic compound of the helicene type with an adjacent double-boron skeleton is the guest material of the organic light-emitting layer with a narrow band gap; ET is the material of the electron transport layer; LiF is the material of the electron injection layer; and aluminum metal is the material of the cathode.

[0028] The structural formulae of the HI, HT, EBL, Host, and ET are as follows, respectively.

[0029]

[0030] It should be noted that the application of the helicene type organic compound described in the application is not limited to the device composition, and the film thickness or composition material of each layer can be appropriately changed based on the basic properties of the structure of the specific compound of the application.

[0031] The beneficial technical effects of the application are as follows: in the compound structure designed in the application, the helical chirality of the molecule is controlled by constructing a rigid skeleton with an adjacent double-boron, thereby ensuring that the designed compound has circularly polarized light emission characteristics on the basis of narrow spectral band light emission characteristics. In the application, the energy level band gap of the molecule can be controlled by expanding the molecular skeleton or modifying the peripheral groups, thereby changing the light emission wavelength and the performance of the material device. The molecular skeleton can be expanded to achieve the purpose of improving the racemization barrier and amplifying the chiral signal. The helicene type organic compound based on the adjacent double-boron skeleton in the application provides a new strategy for the construction of chiral light-emitting molecules and provides a new chiral mother nucleus for circularly polarized light-emitting materials. The chiral light-emitting material designed in the application has great application prospects in three-dimensional display technology, anti-counterfeiting identification, optical information storage, biological imaging, and chiral sensing due to its circularly polarized light emission characteristics. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the prior art, the accompanying drawings needed to be used in the specific embodiments or prior art description will be briefly introduced as follows. Obviously, the accompanying drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort based on these drawings.

[0033] Figure 1 The luminescence spectrum of compound CBN4 measured in toluene solution.

[0034] Figure 2 The chiral resolution preparation result diagram of compound CBN4.

[0035] Figure 3 The circular dichroism spectrum of compound CBN4.

[0036] Figure 4 The circularly polarized luminescence spectrum of compound CBN4.

[0037] Figure 5 The luminescence asymmetric factor of compound CBN4.

[0038] Figure 6 The luminescence spectrum of compound CBN88 measured in toluene solution.

[0039] Figure 7 The chiral resolution preparation result diagram of compound CBN88.

[0040] Figure 8 The circular dichroism spectrum of compound CBN88.

[0041] Figure 9 The circularly polarized luminescence spectrum of compound CBN88.

[0042] Figure 10 The luminescence asymmetric factor of compound CBN88.

[0043] Figure 11 The structural schematic diagram of an organic electroluminescent device in Example 7 of the present application, wherein 1 is a substrate, 2 is an anode, 3 is a hole injection layer, 4 is a hole transport layer, 5 is an electron blocking layer, 6 is an organic light-emitting layer, 7 is an electron transport layer, 8 is an electron injection layer, and 9 is a cathode. DETAILED DESCRIPTION

[0044] The synthesis and device fabrication of the ortho-boron skeleton-based spiro-olene organic compounds of the present application will be described in detail below in connection with a number of embodiments, but are not limited to these synthesis examples. This detailed description should not be considered limitations on the present application, but rather an attempt to provide a more complete description of certain aspects, features, and embodiments of the present application. It is understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the present application.

[0045] Further, for numerical ranges that are disclosed herein, it is intended that every numerical value within the range is also expressly stated. The wording "between" is used herein to describe both an open-ended range and a specific, non- open ended range. For example, a range of "between 1 and 10" or "between 1 and 10" can be interpreted to include the values 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10, as well as any other number in between. The terms "comprises", "comprising", "includes", "including", "has", "having", "contains", "containing", or variations thereof, are intended to be open-ended terms that do not limit any of the specific number of integers, steps, or components to the

[0046] Example 1 Structure and preparation method of CBN1

[0047]

[0048] Preparation method and synthetic route are as follows:

[0049]

[0050] Preparation of intermediate 1: under nitrogen atmosphere, add raw material 1 (2.7 g, 10 mmol) and hydroquinone (550 mg, 5 mmol) and potassium carbonate (2.8 g, 20 mmol), pour into 35 mL of DMF and warm to 150°C and stir for 24 hours. After the reaction is cooled to room temperature, extract with petroleum ether 3 times, combine the organic phases and spin dry. Purify by column chromatography to obtain white intermediate 1 (1.3 g, 41%).

[0051] Preparation of target product CBN1 : 500 mg of intermediate 1 and 1.5 mL of boron tribromide were added to t-butylbenzene containing 10 mL of benzene under nitrogen atmosphere. After warming to 180 °C and stirring for 20 h, it was cooled to room temperature. Methanol was added and the solid was filtered off. Column chromatography was used for separation to obtain the light yellow target product (102 mg, 20%). HR-MS (MALDI-TOF, m / z): [M] + calcd for C 44 H 30 B2N2O2, 882.015; found, 882.485.

[0052] Structure and preparation method of example 2 CBN4

[0053]

[0054] Preparation method and synthetic route are as follows:

[0055]

[0056] Preparation of intermediate 2: 2.7 g of starting material 1 (10 mmol) and 2,3-dimethyl-1,4- hydroquinone (691 mg, 5 mmol) and potassium carbonate (2.8 g, 20 mmol) were added under nitrogen atmosphere, poured into 35 mL of DMF and warmed to 150 °C and stirred for 24 h. After the reaction was cooled to room temperature, it was extracted with petroleum ether 3 times, the organic phases were combined and dried in vacuo. Column chromatography was used for separation and purification to obtain white intermediate 2 (1.3 g, 40%). Preparation of target product CBN4: 522 mg of intermediate 2 and 1.5 mL of boron tribromide were added to t-butylbenzene containing 10 mL of benzene under nitrogen atmosphere. After warming to 180 °C and stirring for 20 h, it was cooled to room temperature. Methanol was added and the solid was filtered off. Column chromatography was used for separation to obtain the light yellow target product (118 mg, 22%). HR-MS (MALDI-TOF, m / z): [M] + calcd for C 46 H 34 B2N2O2, 640.2493, found, 668.2506.

[0057] Figure 1 The luminescence spectrum of compound CBN4 was measured in toluene solution (1 x 10 -5 M). Compound CBN4 exhibited narrow-band deep blue light emission with a maximum emission wavelength of 449 nm and a half-peak width of 24 nm.

[0058] Figure 2Chiral separation of compound CBN4. It can be found that there are two chiral isomers with similar area ratio at the retention time of 4.48 min and 5.96 min, which are P and M configuration respectively, after separation by chiral column.

[0059] Figure 3 Circular dichroism spectrum of compound CBN4. In dilute toluene solution, there is obvious mirror-symmetry absorption spectrum of compound CBN4, with absorption wavelength in the range of 350-600 nm, and the maximum absorption wavelength is 445 nm.

[0060] Figure 4 Circularly polarized luminescence spectrum of compound CBN4. In dilute toluene solution, there is obvious circularly polarized luminescence signal of compound around 450 nm, and the luminescence spectrum intensity of two configurations is similar, showing mirror-symmetry characteristics.

[0061] Figure 5 Luminescence asymmetric factor of compound CBN4. Through the circularly polarized luminescence spectrum of compound in toluene solution, the asymmetric factors of P / M configuration are +2.2 x 10 -3 and -2.5 x 10 -3 .

[0062] Example 3

[0063] Structure and preparation method of CBN9

[0064]

[0065] Preparation method and synthesis route are as follows:

[0066]

[0067] Preparation of intermediate 3: under nitrogen atmosphere, add raw material 2 (2.8 g, 10 mmol) and 2,3-dimethyl-1,4-hydroquinone (691 mg, 5 mmol) and potassium carbonate (2.8 g, 20 mmol) into 35 mL of DMF and stir at 150°C for 24 hours. After the reaction is cooled to room temperature, extract with petroleum ether for 3 times, combine the organic phase and spin dry. Purify by column chromatography to obtain white intermediate 3 (1.3 g, 41%).

[0068] Preparation of target product CBN9: under nitrogen atmosphere, add 519 mg of intermediate 3 and 1.5 mL of boron tribromide into t-butylbenzene containing 10 mL of benzene. After being heated to 180°C and stirred for 20 hours, cool to room temperature. Add methanol and filter the residue after the solid is precipitated. Purify by column chromatography to obtain the light yellow target product (118 mg, 22%). HR-MS (MALDI-TOF, m / z): [M]+ calcd for C 44 H 26 B2N2O2, 636.2180, found, 636.2156.

[0069] Example 4

[0070] Structure and method of preparation of CBN49

[0071]

[0072] The method of preparation and synthetic route are as follows:

[0073]

[0074] Preparation of intermediate 4: under nitrogen atmosphere, add raw material 3 (1.8 g, 10 mmol) and 1,4-hydroquinone (691 mg, 5 mmol) and potassium carbonate (2.8 g, 20 mmol) into 35 mL of DMF and stir at 150°C for 24 hours. After the reaction is cooled to room temperature, extract with petroleum ether 3 times, combine the organic phase and spin dry. Purify by column chromatography to obtain white intermediate 4 (1.3 g, 56%).

[0075] Preparation of intermediate 5: under nitrogen atmosphere, add intermediate 4 (2.2 g, 5 mmol) and diphenylamine (846 mg, 5 mmol) and raw material 4 (1.8 g, 5 mmol) into a two-necked flask containing 30 mL of toluene, 100 mg of Pd2dba3, sodium tert-butoxide (1.9 g, 20 mmol), s-Phos (410 mg, 1 mmol) and stir at 120°C for 4 hours. After the reaction is cooled to room temperature, extract with dichloromethane 3 times, combine the organic phase and spin dry. Purify by column chromatography to obtain white intermediate 5 (1.9 g, 47%).

[0076] Preparation of target product CBN49: under nitrogen atmosphere, add 490 mg of intermediate 5 and 1.2 mL of boron tribromide into tert-butyl benzene containing 10 mL of benzene. After stirring at 180°C for 20 hours and cooling to room temperature, add methanol and filter the residue after the solid precipitates. Purify by column chromatography to obtain the light yellow target product (115 mg, 23%). HR-MS (MALDI-TOF, m / z): [M] + calcd for C 56 H 35 B3N2O4, 832.3356, found, 832.3360.

[0077] Example 5

[0078] Structure and method of preparation of CBN23

[0079]

[0080] The method of preparation and synthetic route are as follows:

[0081]

[0082] Preparation of intermediate 6: under nitrogen atmosphere, add raw material 1-bromo-3-fluoro-5-toluene (1.8 g, 10 mmol) and 2,3-dimethyl-1,4-hydroquinone (691 mg, 5 mmol) and potassium carbonate (2.8 g, 20 mmol) into 35 mL of DMF and stir at 150 °C for 24 hours. After the reaction is cooled to room temperature, extract with petroleum ether for 3 times, combine the organic phase and spin dry. Purify by column chromatography to obtain white intermediate 6 (1.7 g, 71%).

[0083] Preparation of intermediate 7: under nitrogen atmosphere, add intermediate 6 (2.2 g, 5 mmol) and 1,3-dimethylaniline (2.0 g, 10 mmol) into a two-neck flask containing 30 mL of toluene, 100 mg of Pd2dba3, sodium tert-butoxide (1.9 g, 20 mmol), s-Phos (410 mg, 1 mmol) and stir at 120 °C for 4 hours. After the reaction is cooled to room temperature, extract with dichloromethane for 3 times, combine the organic phase and spin dry. Purify by column chromatography to obtain white intermediate 7 (2.3 g, 83%).

[0084] Preparation of intermediate 8: under nitrogen atmosphere, add intermediate 7 (2.8 g, 5 mmol) and 2-bromobenzofuran (2.5 g, 10 mmol) into a two-neck flask containing 25 mL of toluene, 100 mg of Pd2dba3, sodium tert-butoxide (1.9 g, 20 mmol), s-Phos (410 mg, 1 mmol) and stir at 135 °C for 3 hours. After the reaction is cooled to room temperature, extract with dichloromethane for 3 times, combine the organic phase and spin dry. Purify by column chromatography to obtain white intermediate 8 (3.9 g, 88%).

[0085] Preparation of target product CBN23: under nitrogen atmosphere, add 452 mg of intermediate 8 and 1.1 mL of boron tribromide into a pressure-resistant flask containing 10 mL of tert-butylbenzene. After being heated to 180 °C and stirred for 20 hours, cool to room temperature. Add methanol and filter the residue after the solid is precipitated. Purify by column chromatography to obtain the yellowish target product (109 mg, 24%). HR-MS (MALDI-TOF, m / z): [M] + calcd for C 76 H56 B4N2O6, 904.3600, found, 904.3825.

[0086] Example 6

[0087] Structure and preparation method of CBN88

[0088]

[0089] Preparation method and synthetic route are as follows:

[0090]

[0091] Preparation of intermediate 9: under nitrogen atmosphere, aniline (930 mg, 10 mmol) and intermediate 4 (2.2 g, 5 mmol) and potassium carbonate (2.8 g, 20 mmol) were added into 35 mL of DMF and stirred at 100 °C for 24 hours. After the reaction was cooled to room temperature, extraction was performed with petroleum ether 3 times, the organic phase was combined and rotary evaporated. Purification by column chromatography gave intermediate 9 (1.6 g, 68%).

[0092] Preparation of intermediate 10: under nitrogen atmosphere, a two-neck flask containing 30 mL of toluene was added with intermediate 9 (2.4 g, 5 mmol) and raw material 5 (3.5 g, 10 mmol), 100 mg of Pd2dba3, sodium tert-butoxide (1.9 g, 20 mmol), s-Phos (410 mg, 1 mmol) and stirred at 120 °C for 4 hours. After the reaction was cooled to room temperature, extraction was performed with dichloromethane 3 times, the organic phase was combined and rotary evaporated. Purification by column chromatography gave white intermediate 10 (2.1 g, 42%).

[0093] Preparation of target product CBN88: under nitrogen atmosphere, a pressure bottle containing 10 mL of tert-butylbenzene was added with 577 mg of intermediate 10 and 1.1 mL of boron tribromide. After being heated to 180 °C and stirred for 20 hours and cooled to room temperature. Methanol was added and the solid was filtered to obtain the filter residue. Purification by column chromatography gave the yellow target product (117 mg, 20%). HR-MS (MALDI-TOF, m / z): [M] + calcd for C 68 H 40 B4N2O6, 1024.3160, found, 1024.3148.

[0094] Figure 6 The compound CBN88 in toluene solution (1 x 10 -5The luminescence spectrum of compound CBN88 measured in M) is shown in the figure. Compound CBN88 shows narrow-band blue light emission with a maximum emission wavelength of 462 nm and a half-peak width of 21 nm.

[0095] Figure 7 The chiral separation result of compound CBN88 is shown in the figure. It can be found that after separation by a chiral column, the compound has two enantiomers with P and M configurations at a residence time of 4.648 min and 5.439 min, respectively.

[0096] Figure 8 The circular dichroism spectrum of compound CBN88 is shown in the figure. Compound CBN88 has obvious circular dichroism characteristics in a dilute toluene solution, with an absorption wavelength in the range of 300-500 nm and a maximum absorption wavelength of 409 nm.

[0097] Figure 9 The circularly polarized luminescence spectrum of compound CBN88 is shown in the figure. In a dilute toluene solution, the compound has two obvious mirror-symmetric circularly polarized luminescence spectra with a maximum emission wavelength near 465 nm.

[0098] Figure 10 The luminescence asymmetry factor of compound CBN88 is shown in the figure. The circularly polarized luminescence spectrum of the compound in toluene solution was tested, and the asymmetry factors of the two configurations reached +4.8x10 -3 and -4.5x10 -3 .

[0099] Example 7

[0100] This example provides an organic electroluminescent device, as shown in Figure 11 , which comprises, from bottom to top, an anode 2, a hole injection layer 3, a hole transport layer 4, an electron blocking layer 5, an organic light-emitting layer 6, an electron transport layer 7, an electron injection layer 8, and a cathode 9 arranged in sequence on a substrate 1; the specific device structure is as follows: ITO / HI(10 nm) / HT(30 nm) / EBL(10 nm) / Host:1wt% CBN1(30 nm) / ET(30 nm) / LiF(0.5 nm) / Al(150 nm) / , the device is prepared by vacuum evaporation, and the evaporation environment is 2x10 -5 Pa, the evaporation rate of the hole injection layer 3, the hole transport layer 4, the electron blocking layer 5, the organic light-emitting layer 6, the electron transport layer 7, and the electron injection layer 8 is The evaporation rate of the cathode 9 is The anode 2 is selected from ITO material, i.e., indium tin oxide material; the material of the hole injection layer 3 is selected from the compound with the structure described below:

[0101]

[0102] The material of the hole transport layer 4 is selected from a compound with the following structure:

[0103]

[0104] The material of the electron blocking layer 5 is selected from a compound with the following structure:

[0105]

[0106] The organic light-emitting layer 6 is formed by co-doping a host material and a guest material, wherein the host material is selected from a compound Host, the guest material is selected from the spiro compound CBN1 of Example 1, and the doping amount of the guest material accounts for 1% of the total mass of the host material and the guest material; and the chemical structure of the compound Host is shown as follows:

[0107]

[0108] The material of the electron transport layer 7 is selected from a compound with the following structure:

[0109]

[0110] The material of the electron injection layer 8 is selected from LiF;

[0111] The material of the cathode 9 is selected from metal Al.

[0112] The spiro compound of the present application can be used as the material of the organic light-emitting layer in the organic electroluminescent device. In order to verify the luminescent performance of the compound of the present application as the material of the organic light-emitting layer in the organic electroluminescent device, the full width at half maximum (FWHM), the turn-on voltage (V on ), the maximum external quantum efficiency (EQE) and the asymmetry factor (g lum ) of the organic electroluminescent device are tested in the experiment. After applying a direct current voltage, the luminescent characteristics of the organic electroluminescent device prepared in the present embodiment are tested, and the turn-on voltage is 2.8 V, the full width at half maximum is 23 nm, the maximum external quantum efficiency EQE max is 29.3%, and the asymmetry factor is +1.2×10 -3 / -1.4×10 -3 .

[0113] Example 8

[0114] The fabrication method of the device in Example 8 is the same as that in Example 7, except that the organic light-emitting layer material CBN1 is replaced with CBN4. The specific device structure is as follows: ITO / HI (10nm) / HT (30nm) / EBL (10nm) / Host: 1wt% CBN4 (30nm) / ET (30nm) / LiF (0.5nm) / Al (150nm). The organic electroluminescent device fabricated in this example, after applying a DC voltage, exhibits the following luminescence characteristics: a turn-on voltage of 2.7V, a full width at half maximum (FWHM) of 24nm, and a maximum external quantum efficiency (EQE). max The percentage is 33.8%, and the asymmetry factor is +2.2 × 10⁻⁶. -3 / -2.5×10 -3 .

[0115] Example 9

[0116] The fabrication method of the device in Example 9 is the same as that in Example 7, except that the organic light-emitting layer material CBN1 is replaced with CBN49. The specific device structure is as follows: ITO / HI (10nm) / HT (30nm) / EBL (10nm) / Host: 1wt% CBN49 (30nm) / ET (30nm) / LiF (0.5nm) / Al (150nm). The organic electroluminescent device fabricated in this example, after applying a DC voltage, exhibits the following luminescence characteristics: a turn-on voltage of 2.8V, a half-maximum width at half maximum (FWHM) of 19nm, and a maximum external quantum efficiency (EQE). max The percentage is 31.8%, and the asymmetry factor is +4.5 × 10⁻⁶. -3 / -4.7×10 -3 .

[0117] Example 10

[0118] The fabrication method of the device in Example 10 is the same as that in Example 7, except that the organic light-emitting layer material CBN1 is replaced with CBN23. The specific device structure is as follows: ITO / HI (10nm) / HT (30nm) / EBL (10nm) / Host: 1wt% CBN23 (30nm) / ET (30nm) / LiF (0.5nm) / Al (150nm). The organic electroluminescent device fabricated in this example, after applying a DC voltage, exhibits the following luminescence characteristics: a turn-on voltage of 2.7V, a full width at half maximum (FWHM) of 20nm, and a maximum external quantum efficiency (EQE). max The percentage is 33.7%, and the asymmetry factor is +4.9 × 10⁻⁶. -3 / -5.1×10 -3 .

[0119] Example 11

[0120] The method for preparing the device of Example 11 is the same as that of Example 7, except that the organic light-emitting layer material CBN1 used in the organic light-emitting layer is replaced by CBN88, and the specific device structure is as follows: ITO / HI (10 nm) / HT (30 nm) / EBL (10 nm) / Host: 1 wt% CBN88 (30 nm) / ET (30 nm) / LiF (0.5 nm) / Al (150 nm). The organic electroluminescent device prepared in this example was tested for its luminescent properties after a direct current voltage was applied, and a turn-on voltage of 2.8 V, a half-width of 21 nm, a maximum external quantum efficiency EQE of 32.5%, and an asymmetry factor of +4.8x10-4.5x10-4were obtained. max -3 -3 .

[0121] The electroluminescent performance data of the organic electroluminescent devices prepared in Examples 7-11 above are shown in Table 1 below:

[0122] Table 1

[0123] ​​

Claims

1. A helicene-type organic compound based on an ortho-biboron framework, characterized in that, The helicene-type organic compound has the following general formula I structure: R1-R7 can be the same or different, and are independently selected from H, deuterium, halogen, cyano, nitro, amino, substituted or unsubstituted C. l -C 36 Alkyl, C l -C 36 Alkoxy, C3-C 36 cycloalkyl, C6-C 30 aryl, substituted or unsubstituted C3-C 30 heteroaryl, substituted or unsubstituted diarylamino, substituted or unsubstituted diheteroarylamino, substituted or unsubstituted arylheteroarylamino; X1, X2, Y1, and Y2 may be the same or different, and are independently selected from O, NR, S, Se, Te, sulfone, and sulfoxide, respectively. R may be the same or different, and are independently selected from H, deuterium, halogen, cyano, nitro, amino, substituted or unsubstituted C. l -C 36 Alkyl, C l -C 36 Alkoxy, C3-C 36 cycloalkyl, C6-C 30 aryl, substituted or unsubstituted C3-C 30 heteroaryl, substituted or unsubstituted diarylamino, substituted or unsubstituted diheteroarylamino, substituted or unsubstituted arylheteroarylamino; The alkyl, alkoxy, cycloalkyl, aryl, or heteroaryl groups may optionally be substituted with one or more substituents selected from the following: halogen, -CN, C1-C. 12 Alkyl, C1-C 12 Alkoxy, C1-C 12 Haloalkyl, C2-C6 alkenyl, C3-C 10 cycloalkyl, C6-C 14 Aryl and 5- to 18-membered heteroaryl.

2. The helicene-type organic compound based on an ortho-biboron framework as described in claim 1, characterized in that, R1-R7 may be the same or different, and are independently selected from hydrogen, cyano, C1-C4 alkyl, adamantyl, phenyl, cyanophenyl, naphthyl, anthracene, benzo[anthracene], phenanthryl, furanyl, benzo[anthracene], isobenzo[anthracene], dibenzo[anthracene], thiophene, benzo[anthracene], isobenzo[anthracene], dibenzo[anthracene], pyrrole, isoindole, carbazolyl, indoxocabozolyl, pyridyl, quinolinyl, isoquinolinyl, diphenylamino, and dinylamino. Or, in R1-R7, two adjacent groups are connected to each other to form Ra, which may be substituted or unsubstituted C6-C. 30 Aryl, Ra is selected from cyano, C1-C4 alkyl, adamantyl, phenyl, naphthyl, anthracene, benzo[anthracene], phenanthryl, furanyl, benzo[furanyl], isobenzo[furanyl], dibenzo[furanyl], thiophene, benzo[thiophene], isobenzo[thiophene], dibenzo[thiophene], pyrrole, isoindolyl, carbazolyl, indoxocabozolyl, pyridyl, quinolinyl, isoquinolinyl, diphenylamino, and dinaphthylamino.

3. The helicene-type organic compound based on an ortho-biboron framework according to any one of claims 1-2, characterized in that, The helicene-type organic compound is any one of the following compounds:

4. The application of a helicene-type organic compound based on an ortho-biboron framework as described in any one of claims 1-3, characterized in that, The helicene-type organic compound based on the ortho-biboron framework is used as a multiple resonance thermally activated delayed fluorescence material for the fabrication of organic electroluminescent devices.

5. The application of the helicene-type organic compound based on the ortho-biboron framework according to claim 4, characterized in that, The organic electroluminescent device is a circularly polarized organic electroluminescent device.

6. An organic electroluminescent device, the organic electroluminescent device comprising an organic light-emitting layer, the organic light-emitting layer comprising a host material and a guest material, characterized in that, The guest material is a helicene-type organic compound based on an ortho-biboron framework as described in any one of claims 1-3.

7. The organic electroluminescent device according to claim 6, characterized in that, The object material accounts for 1wt%-5wt% of the total mass of the host material and the object material.

8. The organic electroluminescent device according to claim 6, characterized in that, The organic electroluminescent device includes a substrate, an anode, a cathode, and an organic light-emitting layer located between the anode and the cathode.

9. The organic electroluminescent device according to claim 8, characterized in that, The organic electroluminescent device includes a substrate and an anode, a hole injection layer, a hole transport layer, an electron blocking layer, an organic light-emitting layer, an electron transport layer, an electron injection layer, and a cathode electroplated on the substrate.

10. The organic electroluminescent device according to claim 9, characterized in that, ITO is the anode material; HI is the hole injection layer material; HT is the hole transport layer material; EBL is the electron blocking layer material; Host is the host material for the wide bandgap organic light-emitting layer; the helicene-type organic compound with an ortho-biboron framework is the guest material for the narrow bandgap organic light-emitting layer; ET is the electron transport layer material; LiF is the electron injection layer material; and metallic aluminum is the cathode material. The structural formulas of HI, HT, EBL, Host, and ET are shown below:

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