Organic compound, organic light-emitting device and display device

Abstract

The invention relates to an organic compound, an organic light-emitting device and a display device, the organic compound has a structure represented by a general formula (1): # imgabs0 #, the organic compound in the formula (1) has a high first singlet excited state energy level, when the organic compound is used for forming a covering layer of the organic light-emitting device, the light extraction efficiency of the covering layer can be effectively improved, and the light extraction efficiency of the organic light-emitting device is improved. And the light-emitting efficiency of the organic light-emitting device is improved.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to an organic compound, an organic light-emitting device, and a display apparatus. Background Art

[0002] Organic light-emitting diode (OLED) devices, due to their superior display performance, have gained popularity in numerous applications, including primary displays, and have made significant progress towards practical application. However, despite the rapid development of organic electroluminescent technology, it still faces numerous challenges, particularly the need to improve external quantum efficiency (EQE). For OLED devices, luminescence quantum efficiency is not only a comprehensive reflection of device performance but also a key metric for measuring device quality.

[0003] In related technologies, a capping layer (CPL) is used to optimize the light extraction efficiency and color purity of OLED devices. However, the organic materials currently used for the capping layer generally have low light extraction efficiency, resulting in limited improvement in the luminous efficiency of OLED devices. Summary of the Invention

[0004] The present application provides an organic compound, an organic light-emitting device, and a display device. The organic compound can effectively improve the light extraction efficiency of a cover layer and improve the luminous efficiency of the organic light-emitting device.

[0005] The present application provides an organic compound having a structure represented by general formula (1):

[0006]

[0007] in,

[0008] R1, R2 and R3 are at least one selected from hydrogen, fluorine, a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, and a substituted or unsubstituted aromatic group having 6 to 30 carbon atoms;

[0009] n1 is any integer selected from 0, 1, 2, 3, 4, and 5;

[0010] n2 is any integer selected from 0, 1, 2, 3, 4, 5;

[0011] n3 is any integer selected from 0, 1, 2, 3, and 4.

[0012] In some embodiments, when R1, R2, and R3 are selected from substituted alkyl groups or substituted aromatic groups, the substituents are selected from fluorine-containing groups.

[0013] In some embodiments, R1, R2, and R3 are selected from hydrogen, fluorine, trifluoromethyl, fluorine-substituted phenyl, fluorine-substituted biphenyl, trifluoromethyl-substituted phenyl, trifluoromethyl-substituted biphenyl.

[0014] In some embodiments, the organic compound is selected from any one of the following structures:

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

[0021] The present application also provides an organic light-emitting device, comprising:

[0022] a first electrode;

[0023] a light-emitting functional layer, disposed on the first electrode;

[0024] a second electrode, disposed on a side of the light-emitting functional layer away from the first electrode; and

[0025] a covering layer, disposed on a side of the second electrode away from the light-emitting functional layer;

[0026] Wherein, the material of the covering layer includes at least one organic compound as described above.

[0027] In some embodiments, the cover layer includes a first sub-cover layer and a second sub-cover layer, and the first sub-cover layer is located between the second electrode and the second sub-cover layer;

[0028] The material of the first sub-covering layer includes at least one organic compound, and the refractive index of the first sub-covering layer is smaller than the refractive index of the second sub-covering layer.

[0029] In some embodiments, the refractive index of the first sub-cover layer is less than or equal to 1.65, and the refractive index of the second sub-cover layer is greater than or equal to 1.85.

[0030] In some embodiments, a difference between a refractive index of the first sub-cover layer and a refractive index of the second sub-cover layer is greater than or equal to 0.3.

[0031] In some embodiments, the optical band gap E of the organic compound in the first sub-covering layer is g Greater than 3.0eV.

[0032] The present application also provides a display device, which includes the organic light-emitting device as described above.

[0033] The present application provides an organic compound, an organic light-emitting device, and a display device. The organic compound of the present application is an organic compound with phthalimide as its core. When applied to a covering layer of an OLED organic light-emitting device, the light extraction efficiency of the covering layer can be significantly improved. In the structure of the organic compound, the unique connection mode between the nitrogen atom of the phthalimide and the phenyl group can weaken the degree of conjugation between the molecules, so that the organic compound has a higher first singlet excited state energy level, which means that the energy required to go from the ground state to the excited state is larger and the wavelength of the absorbed photons is shorter. Therefore, the probability of photons being absorbed by the organic compound during propagation in the device is lower, and light is more easily extracted from the device. Therefore, the covering layer formed using the organic compound has a higher light extraction efficiency. When the covering layer containing the organic compound is applied to an organic light-emitting device, the luminous efficiency of the organic light-emitting device can be significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic structural diagram of an organic light-emitting device provided in an embodiment of the present application;

[0035] Figure 2 This is a schematic structural diagram of another organic light-emitting device provided in an embodiment of the present application.

[0036] Description of reference numerals:

[0037] 100-organic light-emitting device; 110-driving substrate; 120-first electrode; 130-luminescent functional layer; 131-hole injection layer; 132-hole transport layer; 133-electron blocking layer; 134-luminescent layer; 135-hole blocking layer; 136-electron transport layer; 137-electron injection layer; 140-second electrode; 150-covering layer; 151-first sub-covering layer; 152-second sub-covering layer; 160-protective layer; 170-encapsulation layer. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0039] In this application, unless expressly described to the contrary, the phrase "comprising" any component will be understood to implicitly include other elements, rather than to exclude any other elements. Furthermore, it should be understood that throughout this specification, when an element such as a layer, film, region, or substrate is referred to as being "on" or "over" another element, it can be "directly on" the other element, or intervening elements may be present. Furthermore, "on" or "above" refers to being above the target portion, not necessarily above in terms of gravity.

[0040] The present application provides an organic compound having a structure represented by general formula (1):

[0041]

[0042] in,

[0043] R1, R2 and R3 are at least one selected from hydrogen, fluorine, a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, and a substituted or unsubstituted aromatic group having 6 to 30 carbon atoms;

[0044] n1 is any integer selected from 0, 1, 2, 3, 4, and 5;

[0045] n2 is any integer selected from 0, 1, 2, 3, 4, 5;

[0046] n3 is any integer selected from 0, 1, 2, 3, and 4.

[0047] The expression of “—” crossing a ring structure indicates that the connection site is located at any position on the ring structure that can form a bond.

[0048] Here, "substituted or unsubstituted" means that the hydrogen atoms on the alkyl group or the aromatic group are substituted, or the hydrogen atoms on the alkyl group or the aromatic group are not substituted.

[0049] Among them, R1, R2 and R3 represent the same group or different groups; R1 at different substitution sites on the same benzene ring can be the same group or different groups; R2 at different substitution sites on the same benzene ring can be the same group or different groups; R3 at different substitution sites on the same benzene ring can be the same group or different groups.

[0050] The organic compound represented by formula (1) of the present application has phthalimide as the core, which makes the molecule have good stability. The unique connection mode between the nitrogen atom of phthalimide and the phenyl group in the organic compound, that is, the connection between the nitrogen atom of phthalimide and the middle benzene ring of terphenyl, can weaken the degree of conjugation between molecules, so that the organic compound has a higher first singlet excited state energy level. The higher first singlet excited state energy level of the organic compound means that the energy required to go from the ground state to the excited state is larger, and the wavelength of the absorbed photon is shorter. Therefore, the probability of photons being absorbed by the organic compound during propagation in the device is lower, and light is more easily extracted from the device. Therefore, when the organic compound is used in the covering layer of the organic light-emitting device, it can effectively improve the light extraction efficiency of the covering layer, thereby improving the luminous efficiency of the organic light-emitting device.

[0051] In some embodiments, when R1, R2 and R3 are selected from substituted alkyl groups or substituted aromatic groups, the substituents are selected from fluorine-containing groups, and the fluorine-containing groups can be, for example, fluorine, trifluoromethyl, etc., but are not limited thereto.

[0052] Furthermore, R1, R2 and R3 can be selected from fluorine, trifluoromethyl, fluorine-substituted phenyl, fluorine-substituted biphenyl, trifluoromethyl-substituted phenyl, and trifluoromethyl-substituted biphenyl.

[0053] The introduction of a fluorine-containing group into the benzene ring of the organic compound represented by formula (1) of the present application is beneficial to reducing the refractive index of the material. The further introduction of multiple phenyl groups into the structure with phthalimide as the core can provide more substitution sites for fluorine atoms or trifluoromethyl groups to obtain an organic compound material with a lower refractive index, which can be used to form a low-refractive-index covering layer. When the low-refractive-index covering layer using the organic compound is combined with a high-refractive-index covering layer and applied to an organic light-emitting device, the luminous efficiency of the organic light-emitting device can be significantly improved.

[0054] In some embodiments, the organic compound is selected from any one of the following structures, but is not limited to the following structures:

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061] This application also provides an organic light emitting device 100, please refer to Figure 1 The organic light-emitting device 100 includes a first electrode 120, a light-emitting functional layer 130, a second electrode 140, and a covering layer 150. The light-emitting functional layer 130 is disposed on the first electrode 120; the second electrode 140 is disposed on a side of the light-emitting functional layer 130 away from the first electrode 120; and the covering layer 150 is disposed on a side of the second electrode 140 away from the light-emitting functional layer 130. The material of the covering layer 150 includes at least one organic compound represented by formula (1). In the present application, the organic compound represented by formula (1) is used to form the covering layer, which can significantly improve the light extraction efficiency of the covering layer, thereby improving the luminous efficiency of the organic light-emitting device.

[0062] For further information, please refer to Figure 1 The organic light-emitting device 100 further includes a driving substrate 110 , which is disposed on a side of the first electrode 120 away from the light-emitting functional layer 130 . The driving substrate 110 is used to provide support and driving voltage to enable the light-emitting functional layer 130 to emit light.

[0063] In this application, the driving substrate includes a substrate and a driving circuit disposed on the substrate. The substrate may be glass or a flexible polyimide film; the substrate may be a transparent plastic substrate or an opaque material substrate such as a silicon or stainless steel substrate, but is not limited thereto. The driving circuit includes thin-film transistors, capacitors, wires, and the like. Different driving substrates have different mechanical strengths, thermal stability, transparency, surface smoothness, and water resistance. Depending on the properties of the driving substrate, its use may vary. The specific choice may be based on the performance requirements of the organic light-emitting device and is not limited in this application.

[0064] In the present application, one of the first electrode and the second electrode is an anode, and the other is a cathode. For example, the first electrode can be an anode, and the second electrode can be a cathode.

[0065] The first electrode can be a reflective electrode, such as a reflective film formed from silver (Ag), magnesium (Mg), aluminum (Al), gold (Au), nickel (Ni), chromium (Cr), or alloys thereof. The first electrode can also be an electrode composed of a reflective film and a transparent or semi-transparent electrode, such as a transparent or semi-transparent electrode layer with a high work function formed on the reflective film. The transparent or semi-transparent electrode layer can be formed from indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), aluminum zinc oxide (AZO), indium gallium oxide (IGO), indium oxide (In2O3), or tin oxide (SnO2). It can also be a combination of a metal and an oxide, such as ITO / Ag / ITO, IGO / Al / IGO, or AZO / Ag / AZO. Light emitted by the light-emitting functional layer can be reflected from the first electrode toward the second electrode and then emitted from the second electrode. The first electrode can be formed by sputtering, ion plating, vacuum evaporation, spin coating, electron beam evaporation, or chemical vapor deposition (CVD), preferably by sputtering. The thickness of the first electrode layer depends on the material used. The thickness of the first electrode layer ranges from 5 nm to 1 μm, preferably from 10 nm to 1 μm, more preferably from 10 nm to 500 nm, particularly preferably from 10 nm to 300 nm, and most preferably from 10 nm to 200 nm.

[0066] The second electrode can be a transparent or semi-transparent electrode, for example, a thin film with a low work function made from lithium, calcium, lithium fluoride / calcium, lithium fluoride / aluminum, aluminum, silver, magnesium, or their alloys. Furthermore, the second electrode layer can be made from an alloy comprising silver and at least one metal, including aluminum, platinum, ytterbium, chromium, or magnesium, wherein the weight ratio of silver in the alloy can be the same as, or greater or less than, the weight ratio of the other metals. For example, the second electrode layer can be formed from a silver-magnesium alloy, wherein the weight ratio of silver to magnesium can be between 90:10 and 10:90. Alternatively, the second electrode layer can be formed from an alloy comprising at least one metal such as silver, gold, platinum, copper, nickel, or tungsten, and at least one metal such as ytterbium, indium, magnesium, or chromium. Films formed from these metals can be formed into transparent or semi-transparent electrodes by adjusting the film thickness, so that light generated by the light-emitting functional layer can be emitted through the second electrode layer. The thickness of the second electrode layer ranges from 5 nm to 20 nm. The second electrode can be formed by methods such as vacuum evaporation.

[0067] In the present application, the light-emitting functional layer may include one or more film layers, and the light-emitting functional layer includes at least a light-emitting layer. Furthermore, when the light-emitting functional layer includes multiple film layers, it may also include at least one of a hole transport layer, a hole injection layer, an electron blocking layer, a hole blocking layer, an electron transport layer, and an electron injection layer. Among them, at least one of a hole injection layer, a hole transport layer, and an electron blocking layer may be included between the first electrode and the light-emitting layer, and at least one of a hole blocking layer, an electron transport layer, and an electron injection layer may be included between the second electrode and the light-emitting layer. Among them, the thickness of the light-emitting functional layer ranges from 50nm to 1000nm. The light-emitting functional layer can be formed by vacuum evaporation, solution spin coating, screen printing, or inkjet printing.

[0068] Please refer to Figure 2 Taking the first electrode 120 as the anode and the second electrode 140 as the cathode as an example, the light-emitting functional layer 130 includes a light-emitting layer 134, a hole injection layer 131, a hole transport layer 132, an electron blocking layer 133, a hole blocking layer 135, an electron transport layer 136, and an electron injection layer 137, wherein the hole injection layer 131 is located on the side of the first electrode 120 away from the driving substrate 110, the hole transport layer 132 is located on the side of the hole injection layer 131 away from the first electrode 120, the electron blocking layer 133 is located on the side of the hole transport layer 132 away from the hole injection layer 131, the light-emitting layer 134 is located on the side of the electron blocking layer 133 away from the hole transport layer 132, the hole blocking layer 135 is located on the side of the light-emitting layer 134 away from the electron blocking layer 133, the electron transport layer 136 is located on the side of the hole blocking layer 135 away from the light-emitting layer 134, and the electron injection layer 137 is located between the electron transport layer 136 and the second electrode 140.

[0069] The materials of the light-emitting layer include a host material and a dopant material. The host material needs to have bipolar charge transfer properties and an appropriate energy level to effectively transfer the excitation energy generated by the recombination of electrons and holes to the guest light-emitting material, i.e., the dopant material. The host material can be a distyryl arylene derivative, a stilbene derivative, a carbazole derivative, a triarylamine derivative, an anthracene derivative, a pyrene derivative, a triazine derivative, a xanthone derivative, a triphenylene derivative, a triazine derivative, a hexaphenylene derivative, or bis(2-methyl-8-quinolinol)(p-phenylphenol)aluminum (BAlq). The dopant material can be at least one of a fluorescent material, a delayed fluorescence (TADF) material, or a phosphorescent material.

[0070] The light-emitting layer may include one or more sub-light-emitting layers of one or more colors, including at least one of a red sub-light-emitting layer, a green sub-light-emitting layer, and a blue sub-light-emitting layer. The red sub-light-emitting layer includes a red light-emitting material, the green sub-light-emitting layer includes a green light-emitting material, and the blue sub-light-emitting layer includes a blue light-emitting material. To optimize the effective binding of charge carriers within the light-emitting layer, the thickness of the light-emitting layer may be adjusted as needed, or different light-emitting layers may be alternately stacked and combined as needed. Charge blocking layers with different functionalities may also be added between adjacent light-emitting layers.

[0071] The materials for the hole injection layer, the hole transport layer, and the electron blocking layer can be any material selected from known materials used in OLED organic light-emitting devices. Furthermore, at least one of the hole injection layer and the hole transport layer may also include a charge generating material for improving conductivity, and the charge generating material may be a p-dopant, and the p-dopant may be: a quinone derivative, such as tetracyanoquinodimethane (TCNQ) and 2,3,5,6-tetrafluoro-tetracyano-1,4-benzoquinodimethane (F4-TCNQ); or a hexaazatriphenylene derivative, such as 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT-CN); or a cyclopropane derivative, such as 4,4',4"-((1E,1'E,1"E)-cyclopropane-1,2,3-trimethylenetris(cyanoformyl))tris(2,3,5,6-tetrafluorobenzyl); or a metal oxide, such as tungsten oxide and molybdenum oxide, but not limited thereto.

[0072] The triplet state (T1) energy level of the electron blocking layer material must be higher than the T1 energy level of the main material in the light-emitting layer, which can block the energy loss of the light-emitting layer material. The highest occupied molecular orbital (HOMO) energy level of the electron blocking layer material is between the HOMO energy level of the hole transport layer material and the HOMO energy level of the main material of the light-emitting layer, so as to facilitate the injection of holes from the anode into the light-emitting layer. At the same time, the electron blocking layer material is required to have a high hole mobility to facilitate hole transport and reduce the application power of the device. The lowest unoccupied molecular orbital (LUMO) energy level of the electron blocking layer material is higher than the LUMO energy level of the main material of the light-emitting layer to play an electron blocking role, that is, the electron blocking layer material is required to have a wide band gap (Eg). Specifically, the electron blocking layer material can be a triarylamine derivative, a fluorene derivative, a spirofluorene derivative, a dibenzofuran derivative, or a carbazole derivative. Among them, preferred are triarylamine derivatives, such as N4,N4-bis([1,1'-biphenyl]-4-yl)-N4'-phenyl N4'-[1,1'4',1"-terphenyl]-4-yl-[1,1'-biphenyl]-4,4'-diamine; spirofluorene derivatives, such as N-([1,1'-diphenyl]-4-yl)-N-(9,9-dimethyl-9H-furan-2-yl)-9,9'-spirobifluorene-2-amine; dibenzofuran derivatives, such as N,N-di([1,1'-biphenyl]-4-yl)-3'-(dibenzo[b,d]furan-4-yl)-[1,1'-biphenyl]-4-amine, but are not limited thereto.

[0073] The materials of the hole blocking layer and the electron transport layer are materials having electron transport properties, and any material can be selected from known materials used in OLED organic light-emitting devices. The material having electron transport properties may be 1,3-bis[5'-(p-tert-butylphenyl)-1,3,4-oxadiazole-2'-yl]benzene, 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole and other oxadiazole derivatives, 3-(4'-tert-butylphenyl)-4-phenyl-5-(4"-biphenyl)-1,2,4-triazole and other triazole derivatives, triazine derivatives, quinoline derivatives, quinoxaline derivatives, diphenylquinone derivatives, nitro-substituted quinone derivatives, thiopyran dioxide derivatives, anthraquinone dimethane derivatives, thiopyran dioxide derivatives, heterocyclic tetracarboxylic anhydrides such as naphthyl perylene, carbodiimides, quinone derivatives, anthraquinone dimethane derivatives, anthrone derivatives, distyrylpyrazine derivatives, silcyclopentadiene derivatives, diazophenanthroline derivatives or imidazopyridine derivatives, etc.

[0074] In the present application, the covering layer can be formed from an organic compound represented by formula (1), or from an organic compound represented by formula (1) and an organic compound having an aromatic amine structure. The covering layer can be formed by vacuum evaporation, solution spin coating, screen printing, or inkjet printing.

[0075] In some embodiments, please refer to Figure 1 The covering layer 150 includes a first sub-covering layer 151 and a second sub-covering layer 152, the first sub-covering layer 151 is located between the second electrode 140 and the second sub-covering layer 152, and the refractive index of the first sub-covering layer 151 is less than the refractive index of the second sub-covering layer 152; wherein the material of the first sub-covering layer 151 includes at least one organic compound represented by formula (1).

[0076] In some embodiments, the second sub-covering layer includes an organic compound with a high refractive index. For example, the material of the second sub-covering layer may include at least one of the following compounds, but is not limited to the following compounds:

[0077]

[0078] In the present application, the covering layer is a double covering layer structure consisting of a first sub-covering layer with a low refractive index and a second sub-covering layer with a high refractive index. In the double covering layer structure, due to the refractive index difference between the second sub-covering layer with a high refractive index and the first sub-covering layer with a low refractive index, part of the light emitted by the light-emitting functional layer passes through the covering layer, and the other part is reflected by the covering layer. In particular, at the interface between the second sub-covering layer with a high refractive index and the first sub-covering layer with a low refractive index, and at the interface between the second sub-covering layer with a high refractive index and the encapsulation layer above it, the reflection phenomenon of light is particularly obvious. The light reflected by the covering layer is reflected again at the second electrode and is enhanced during the repeated reflection process. Therefore, the light can be repeatedly reflected between the interface between the second sub-covering layer with a high refractive index and the first sub-covering layer with a low refractive index, and between the interface between the second sub-covering layer with a high refractive index and the encapsulation layer above it, thereby recovering the light lost to the device surface due to reflection. Therefore, the double covering layer structure consisting of the first sub-covering layer with a low refractive index and the second sub-covering layer with a high refractive index is more conducive to improving the light extraction efficiency and further improving the luminous efficiency of the organic light-emitting device.

[0079] The organic compound represented by formula (1) is used to form the first sub-covering layer, which can obtain a lower refractive index. When combined with the second sub-covering layer having a high refractive index, the light extraction efficiency of the entire covering layer can be significantly improved.

[0080] In some embodiments, the refractive index of the first sub-cover layer is less than or equal to 1.65, and the refractive index of the second sub-cover layer is greater than or equal to 1.85.

[0081] Among them, the refractive index of the first sub-covering layer at a wavelength of 460nm (blue light) is less than or equal to 1.65, preferably less than or equal to 1.60, further preferably less than or equal to 1.55, further preferably less than or equal to 1.55, and further preferably less than or equal to 1.50. The refractive index range of the first sub-covering layer at a wavelength of 460nm (blue light) is preferably 1.4 to 1.65; the refractive index of the first sub-covering layer at a wavelength of 525nm (green light) is less than or equal to 1.65, preferably less than or equal to 1.60, further preferably less than or equal to 1.55, further preferably less than or equal to 1.55, and further preferably less than or equal to 1.50; the refractive index of the first sub-covering layer at a wavelength of 620nm (red light) is less than or equal to 1.65, preferably less than or equal to 1.60, further preferably less than or equal to 1.55, further preferably less than or equal to 1.55, and further preferably less than or equal to 1.50.

[0082] The refractive index of the second sub-cover layer at a wavelength of 460 nm (blue light) is greater than or equal to 1.85, preferably greater than or equal to 1.9, further preferably greater than or equal to 2.0, further preferably greater than or equal to 2.1, further preferably greater than or equal to 2.2, and more preferably greater than or equal to 2.3; the refractive index of the second sub-cover layer at a wavelength of 525 nm (green light) is greater than or equal to 1.85, preferably greater than or equal to 1.9, further preferably greater than or equal to 2.0, further preferably greater than or equal to 2.1, further preferably greater than or equal to 2.2, and more preferably greater than or equal to 2.3; the refractive index of the second sub-cover layer at a wavelength of 620 nm (red light) is greater than or equal to 1.85, preferably greater than or equal to 1.9, further preferably greater than or equal to 2.0, further preferably greater than or equal to 2.1, further preferably greater than or equal to 2.2, and more preferably greater than or equal to 2.3.

[0083] In some embodiments, the difference between the refractive index of the first sub-cover layer at a wavelength of 460nm and the refractive index of the first sub-cover layer at a wavelength of 620nm is less than or equal to 0.3, so that the light extraction efficiency of light of different colors is more balanced, thereby improving the overall luminous efficiency of the light-emitting device.

[0084] In some embodiments, the difference between the refractive index of the first sub-covering layer and the refractive index of the second sub-covering layer is greater than or equal to 0.3, further preferably greater than or equal to 0.4, further preferably greater than or equal to 0.5, further preferably greater than or equal to 0.6, more preferably greater than or equal to 0.7, and most preferably greater than or equal to 0.8, so as to reduce the total reflection of light at the interface and improve the light extraction efficiency.

[0085] For example, a difference between the refractive index of the first sub-cover layer at a wavelength of 460 nm and the refractive index of the second sub-cover layer at a wavelength of 460 nm may be greater than or equal to 0.3.

[0086] In some embodiments, the optical band gap E of the organic compound in the first sub-covering layer is g Greater than 3.0 eV, preferably greater than 3.5 eV. g When it is greater than the above range, it means that the material of the first sub-covering layer has a higher first singlet excited state energy level, and the first sub-covering layer has weaker absorption of the visible light band. During the process of light propagating in the device, the probability of being absorbed by the first sub-covering layer is low, and it is easier to be taken out of the device, which is beneficial to improving the overall luminous efficiency of the light-emitting device.

[0087] In some embodiments, the thickness of the cover layer ranges from 15 nm to 300 nm, preferably from 30 nm to 200 nm, more preferably from 40 nm to 100 nm, and most preferably from 50 nm to 80 nm; the thickness of the first sub-cover layer ranges from 1 nm to 150 nm, preferably from 5 nm to 100 nm, and more preferably from 10 nm to 50 nm; and the thickness of the second sub-cover layer ranges from 1 nm to 150 nm, preferably from 5 nm to 100 nm, and more preferably from 10 nm to 50 nm. The thickness of the first sub-cover layer and the thickness of the second sub-cover layer may be the same or different.

[0088] In some embodiments, please refer to Figure 2 The organic light-emitting device 100 further includes a protective layer 160, which is disposed on a side of the cover layer 150 away from the light-emitting functional layer 130 to protect the cover layer 150. The protective layer 160 may be an inorganic material, such as, but not limited to, lithium fluoride (LiF). The thickness of the protective layer 160 ranges from 20 nm to 400 nm, preferably from 30 nm to 200 nm, and more preferably from 40 nm to 100 nm. Specifically, the thickness of the protective layer 160 depends on the material used.

[0089] In some embodiments, please refer to Figure 2 , the organic light-emitting device 100 also includes an encapsulation layer 170, which is arranged on the side of the protective layer 160 away from the covering layer 150 to cover the protective layer 160, the covering layer 150, and the light-emitting functional layer 130. The encapsulation layer 170 is used to prevent foreign substances such as moisture and oxygen from entering the organic layer of the organic light-emitting device to avoid water and oxygen intrusion causing display abnormalities. The encapsulation layer 170 may include one or more film layers. For example, the encapsulation layer 170 may include a first encapsulation layer, a second encapsulation layer, and a third encapsulation layer that are stacked, the first encapsulation layer being an inorganic layer, the second encapsulation layer being an organic layer, and the third encapsulation layer being an inorganic layer; the material of the inorganic layer may be selected from Al2O3, SiO x N y 、TiO2、SiO x and SiN xAt least one of , wherein x and y are the same or different, x and y are greater than 0 and less than 10, preferably greater than 0 and less than 5, more preferably greater than 0 and less than 3, the inorganic layer can be prepared by a chemical vapor deposition (CVD) method; the material of the organic layer can use the encapsulation layer organic material for OLED organic light-emitting devices known in the prior art, for example, the material of the organic layer can be at least one of polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), polystyrene (PS), a polymer derivative having a phenol group, an acrylic polymer (acryl-based polymer), an imide polymer (imide-based polymer), an arylether polymer (arylether-based polymer), an amide polymer (amide-based polymer), a fluorine polymer (fluorine-based polymer), a p-xylene polymer (p-xylene-based polymer) or a vinyl alcohol polymer (vinylalcohol-based polymer), and the organic layer can be formed by curing the organic material by UV curing.

[0090] The present application also provides a display device comprising the organic light-emitting device described above. The display device can be used in, but is not limited to, smartphones, tablet computers, smart wearable devices, televisions, virtual reality (VR), microdisplays, and automotive central control screens.

[0091] The organic compound and the organic light-emitting device of the present application are further described below through specific examples, but the present application is not limited to the following examples.

[0092] 1. Synthesis of organic compounds

[0093] (1) Synthesis of Compound M1:

[0094]

[0095] Compound 1-1 (10 mmol) and compound 1-2 (10 mmol) were dissolved in toluene and stirred at 120°C for 12 h under a nitrogen atmosphere. The reaction mixture was cooled to room temperature, and a portion of the solvent was removed using a rotary evaporator. The mixture was then extracted three times with dichloromethane and water. After separation, the mixture was dried over MgSO4 and filtered, and the solvent was removed under reduced pressure. The crude product was purified by column chromatography to obtain compound M1 with a yield of 87%. Mass spectrometry analysis showed m / z [H + ]=375.

[0096] (2) Synthesis of Compound M2:

[0097]

[0098] Compound 2-1 (10 mmol), compound 2-2 (30 mmol), Pd(PPh3)4 (0.1 mmol) and potassium carbonate (30 mmol) were dissolved in a mixed solvent of 1,4-dioxane and water and stirred at 100°C for 6 h under a nitrogen atmosphere. After the reaction system was cooled to room temperature, a portion of the solvent was removed using a rotary evaporator, and then extracted three times with dichloromethane and water. After separation, the organic phase was dried to obtain a crude product. The crude product was purified by column chromatography to obtain intermediate 2-3 with a yield of 82%. The mass spectrometry results showed that m / z [H + ]=425.

[0099] The synthesis method of compound M2 refers to the synthesis operation steps of the above-mentioned compound M1, wherein the intermediate 2-3 replaces the compound 1-2 in the synthesis method of compound M1, and the compound 2-4 replaces the compound 1-1 in the synthesis method of compound M1 to obtain compound M1. The yield is 87%. The mass spectrometry analysis result m / z [H + ]=627.

[0100] (3) Synthesis of Compound M3:

[0101]

[0102] The synthesis method of intermediate 3-3 refers to the synthesis operation steps of intermediate 2-3, wherein compound 3-1 replaces compound 2-1 in the synthesis method of intermediate 2-3, and compound 3-2 replaces compound 2-2 in the synthesis method of intermediate 2-3, to obtain intermediate 3-3, with a yield of 87%. The mass spectrometry analysis result m / z [H + ]=517.

[0103] The synthesis method of compound M3 refers to the synthesis operation steps of compound M1 above, wherein intermediate 3-3 replaces compound 1-2 in the synthesis method of compound M1, and compound 3-4 replaces compound 1-1 in the synthesis method of compound M1 to obtain compound M3. The yield is 82%. The mass spectrometry analysis result m / z [H + ]=719.

[0104] (4) Synthesis of Compound M4:

[0105]

[0106] The synthesis method of intermediate 4-3 refers to the synthesis operation steps of intermediate 2-3, wherein compound 4-1 replaces compound 2-1 in the synthesis method of intermediate 2-3, and compound 4-2 replaces compound 2-2 in the synthesis method of intermediate 2-3, to obtain intermediate 4-3, with a yield of 80%. The mass spectrometry analysis result m / z [H + ]=517.

[0107] The synthesis method of compound M4 refers to the synthesis operation steps of compound M1 above, wherein intermediate 4-3 replaces compound 1-2 in the synthesis method of compound M1, and compound 4-4 replaces compound 1-1 in the synthesis method of compound M1 to obtain compound M4. The yield is 84%. The mass spectrometry analysis result m / z [H + ]=719.

[0108] (5) Synthesis of Compound M5:

[0109]

[0110] The synthesis of intermediate 2-3 was carried out by referring to the synthetic steps of intermediate 2-3, wherein compound 5-1 was substituted for compound 2-1 in the synthetic method of intermediate 2-3, and compound 5-2 was substituted for compound 2-2 in the synthetic method of intermediate 2-3, to obtain intermediate 5-3, with a yield of 82%. The mass spectrometry analysis results showed that m / z [H + ]=425.

[0111] The synthesis method of compound M5 refers to the synthesis operation steps of the above-mentioned compound M1, wherein the intermediate 5-3 replaces the compound 1-2 in the synthesis method of compound M1, and the compound 5-4 replaces the compound 1-1 in the synthesis method of compound M1 to obtain compound M5. The yield is 87%. The mass spectrometry analysis result m / z [H + ]=691.

[0112] (6) Synthesis of Compound M6:

[0113]

[0114] The synthesis method of intermediate 6-3 refers to the synthesis operation steps of intermediate 2-3, wherein compound 6-1 replaces compound 2-1 in the synthesis method of intermediate 2-3, and compound 6-2 replaces compound 2-2 in the synthesis method of intermediate 2-3, to obtain intermediate 6-3, with a yield of 82%. The mass spectrometry analysis result m / z [H + ]=517.

[0115] The synthesis method of compound M6 refers to the synthesis operation steps of the above-mentioned compound M1, wherein the intermediate 6-3 replaces the compound 1-2 in the synthesis method of compound M1, and the compound 6-4 replaces the compound 1-1 in the synthesis method of compound M1 to obtain compound M6. The yield is 86%. The mass spectrometry analysis result m / z [H + ]=783.

[0116] (7) Synthesis of Compound M7:

[0117]

[0118] The synthesis method of intermediate 7-3 refers to the synthesis operation steps of intermediate 2-3, wherein compound 7-1 replaces compound 2-1 in the synthesis method of intermediate 2-3, and compound 7-2 replaces compound 2-2 in the synthesis method of intermediate 2-3, to obtain intermediate 7-3, with a yield of 84%. The mass spectrometry analysis results are m / z [H + ]=517.

[0119] The synthesis method of compound M7 refers to the synthesis operation steps of the above-mentioned compound M1, wherein the intermediate 7-3 replaces the compound 1-2 in the synthesis method of compound M1, and the compound 7-4 replaces the compound 1-1 in the synthesis method of compound M1 to obtain compound M7. The yield is 81%. The mass spectrometry analysis result m / z [H + ]=783.

[0120] (8) Synthesis of Compound M8:

[0121]

[0122] The synthesis method of intermediate 8-3 refers to the synthesis operation steps of intermediate 2-3, wherein compound 8-1 replaces compound 2-1 in the synthesis method of intermediate 2-3, and compound 8-2 replaces compound 2-2 in the synthesis method of intermediate 2-3, to obtain intermediate 8-3, with a yield of 84%. The mass spectrometry analysis result m / z [H + ]=425.

[0123] The synthesis method of intermediate 8-5 refers to the synthesis operation steps of the above-mentioned compound M1, wherein intermediate 8-3 is substituted for compound 1-2 in the synthesis method of compound M1, and compound 8-4 is substituted for compound 1-1 in the synthesis method of compound M1 to obtain intermediate M8-5. The yield is 82%. The mass spectrometry analysis result m / z [H + ]=634.

[0124] Synthesis of compound M8:

[0125] Compound 8-5 (10 mmol), compound 8-6 (30 mmol), Pd(PPh3)4 (0.1 mmol) and potassium carbonate (30 mmol) were dissolved in a mixed solvent of 1,4-dioxane and water and stirred at 100°C for 5 h under a nitrogen atmosphere. After the reaction system was cooled to room temperature, a portion of the solvent was removed using a rotary evaporator, and then extracted three times with dichloromethane and water. After separation, the organic phase was dried to obtain a crude product. The crude product was purified by column chromatography to obtain compound M8 with a yield of 80%. The mass spectrometry results showed that m / z [H + ]=721.

[0126] (9) Synthesis of Compound M9:

[0127]

[0128] The synthesis method of intermediate 9-3 refers to the synthesis operation steps of intermediate 2-3, wherein compound 9-1 replaces compound 2-1 in the synthesis method of intermediate 2-3, and compound 9-2 replaces compound 2-2 in the synthesis method of intermediate 2-3, to obtain intermediate 9-3, with a yield of 82%. The mass spectrometry analysis result m / z [H + ]=425.

[0129] The synthesis method of intermediate 9-5 refers to the synthesis operation steps of the above-mentioned compound M1, wherein intermediate 9-3 is substituted for compound 1-2 in the synthesis method of compound M1, and compound 9-4 is substituted for compound 1-1 in the synthesis method of compound M1 to obtain intermediate M9-5. The yield is 81%. The mass spectrometry analysis result m / z [H + ]=634.

[0130] The synthesis method of compound M9 refers to the synthesis steps of compound M8, wherein intermediate 9-5 replaces compound 8-5 in the synthesis method of compound M8, and compound 9-6 replaces compound 8-6 in the synthesis method of compound M8 to obtain intermediate M9. The yield is 85%. The mass spectrometry analysis result m / z [H + ]=767.

[0131] (10) Synthesis of Compound M10:

[0132]

[0133] The synthesis method of intermediate 10-3 refers to the synthesis operation steps of intermediate 2-3, wherein compound 10-1 replaces compound 2-1 in the synthesis method of intermediate 2-3, and compound 10-2 replaces compound 2-2 in the synthesis method of intermediate 2-3, to obtain intermediate 10-3, with a yield of 84%. The mass spectrometry analysis result m / z [H +]=425.

[0134] The synthesis method of intermediate 10-5 refers to the synthesis operation steps of the above-mentioned compound M1, wherein intermediate 10-3 is substituted for compound 1-2 in the synthesis method of compound M1, and compound 10-4 is substituted for compound 1-1 in the synthesis method of compound M1 to obtain intermediate M10-5. The yield is 83%. The mass spectrometry analysis result m / z [H + ]=634.

[0135] The synthesis method of compound M10 refers to the synthesis steps of compound M8, wherein intermediate 10-5 replaces compound 8-5 in the synthesis method of compound M8, and compound 10-6 replaces compound 8-6 in the synthesis method of compound M8 to obtain intermediate M10 with a yield of 81%. The mass spectrometry analysis results are m / z [H + ]=767.

[0136] (11) Synthesis of Compound M11:

[0137]

[0138] The synthesis method of intermediate 11-3 refers to the synthesis operation steps of intermediate 2-3, wherein compound 11-1 replaces compound 2-1 in the synthesis method of intermediate 2-3, and compound 11-2 replaces compound 2-2 in the synthesis method of intermediate 2-3 to obtain intermediate 11-3. The yield is 86%. The mass spectrometry analysis result m / z [H + ]=517.

[0139] The synthesis method of intermediate 11-5 refers to the synthesis operation steps of the above-mentioned compound M1, wherein intermediate 11-3 replaces compound 1-2 in the synthesis method of compound M1, and compound 11-4 replaces compound 1-1 in the synthesis method of compound M1, to obtain intermediate M11-5, with a yield of 83%. The mass spectrometry analysis result m / z [H + ]=726.

[0140] The synthesis method of compound M11 refers to the synthesis steps of compound M8, wherein intermediate 11-5 replaces compound 8-5 in the synthesis method of compound M8, and compound 11-6 replaces compound 8-6 in the synthesis method of compound M8 to obtain intermediate M11. The yield is 82%. The mass spectrometry analysis result m / z [H + ]=813.

[0141] (12) Synthesis of Compound M12:

[0142]

[0143] The synthesis method of intermediate 12-3 refers to the synthesis operation steps of intermediate 2-3, wherein compound 12-1 replaces compound 2-1 in the synthesis method of intermediate 2-3, and compound 12-2 replaces compound 2-2 in the synthesis method of intermediate 2-3, to obtain intermediate 12-3, with a yield of 84%. The mass spectrometry analysis result m / z [H + ]=517.

[0144] The synthesis method of intermediate 12-5 refers to the synthesis operation steps of the above-mentioned compound M1, wherein intermediate 12-3 replaces compound 1-2 in the synthesis method of compound M1, and compound 12-4 replaces compound 1-1 in the synthesis method of compound M1 to obtain intermediate M12-5. The yield is 82%. The mass spectrometry analysis result m / z [H + ]=726.

[0145] The synthesis method of compound M12 refers to the synthesis steps of compound M8, wherein intermediate 12-5 replaces compound 8-5 in the synthesis method of compound M8, and compound 12-6 replaces compound 8-6 in the synthesis method of compound M8 to obtain intermediate M12 with a yield of 82%. The mass spectrometry analysis results are m / z [H + ]=859.

[0146] (13) Synthesis of Compound M13:

[0147]

[0148] The synthesis method of intermediate 13-3 refers to the synthesis operation steps of intermediate 2-3, wherein compound 13-1 replaces compound 2-1 in the synthesis method of intermediate 2-3, and compound 13-2 replaces compound 2-2 in the synthesis method of intermediate 2-3, to obtain intermediate 13-3, with a yield of 82%. The mass spectrometry analysis result m / z [H + ]=517.

[0149] The synthesis method of intermediate 13-5 refers to the synthesis operation steps of the above-mentioned compound M1, wherein intermediate 13-3 replaces compound 1-2 in the synthesis method of compound M1, and compound 13-4 replaces compound 1-1 in the synthesis method of compound M1 to obtain intermediate M13-5. The yield is 83%. The mass spectrometry analysis result m / z [H + ]=726.

[0150] The synthesis method of compound M13 refers to the synthesis steps of compound M8, wherein intermediate 13-5 replaces compound 8-5 in the synthesis method of compound M8, and compound 13-6 replaces compound 8-6 in the synthesis method of compound M8 to obtain intermediate M13. The yield is 85%. The mass spectrometry analysis result m / z [H+ ]=859.

[0151] (14) Synthesis of Compound M14:

[0152]

[0153] The synthesis method of intermediate 14-3 refers to the synthesis operation steps of intermediate 2-3, wherein compound 14-1 replaces compound 2-1 in the synthesis method of intermediate 2-3, and compound 14-2 replaces compound 2-2 in the synthesis method of intermediate 2-3, to obtain intermediate 14-3, with a yield of 83%. The mass spectrometry analysis result m / z [H + ]=517.

[0154] The synthesis method of intermediate 14-5 refers to the synthesis operation steps of the above-mentioned compound M1, wherein intermediate 14-3 replaces compound 1-2 in the synthesis method of compound M1, and compound 14-4 replaces compound 1-1 in the synthesis method of compound M1 to obtain intermediate M14-5. The yield is 81%. The mass spectrometry analysis result m / z [H + ]=724.

[0155] The synthesis method of compound M14 refers to the synthesis steps of compound M8, wherein intermediate 14-5 replaces compound 8-5 in the synthesis method of compound M8, and compound 14-6 replaces compound 8-6 in the synthesis method of compound M8 to obtain intermediate M14 with a yield of 85%. The mass spectrometry analysis results are m / z [H + ]=813.

[0156] (15) Synthesis of Compound M15:

[0157]

[0158] The synthesis method of intermediate 15-3 refers to the synthesis operation steps of intermediate 2-3, wherein compound 15-1 replaces compound 2-1 in the synthesis method of intermediate 2-3, and compound 15-2 replaces compound 2-2 in the synthesis method of intermediate 2-3, to obtain intermediate 15-3, with a yield of 82%. The mass spectrometry analysis result m / z [H + ]=517.

[0159] The synthesis method of intermediate 15-5 refers to the synthesis operation steps of the above-mentioned compound M1, wherein intermediate 15-3 replaces compound 1-2 in the synthesis method of compound M1, and compound 15-4 replaces compound 1-1 in the synthesis method of compound M1 to obtain intermediate M15-5. The yield is 84%. The mass spectrometry analysis result m / z [H + ]=724.

[0160] The synthesis method of compound M15 refers to the synthesis steps of compound M8, wherein intermediate 15-5 replaces compound 8-5 in the synthesis method of compound M8, and compound 15-6 replaces compound 8-6 in the synthesis method of compound M8 to obtain intermediate M15. The yield is 80%. The mass spectrometry analysis result m / z [H + ]=813.

[0161] (16) Synthesis of Compound M16:

[0162]

[0163] The synthesis method of intermediate 16-3 refers to the synthesis operation steps of intermediate 2-3, wherein compound 16-1 replaces compound 2-1 in the synthesis method of intermediate 2-3, and compound 16-2 replaces compound 2-2 in the synthesis method of intermediate 2-3 to obtain intermediate 16-3. The yield is 84%. The mass spectrometry analysis result m / z [H + ]=517.

[0164] The synthesis method of intermediate 16-5 refers to the synthesis operation steps of the above-mentioned compound M1, wherein intermediate 16-3 replaces compound 1-2 in the synthesis method of compound M1, and compound 16-4 replaces compound 1-1 in the synthesis method of compound M1 to obtain intermediate M16-5. The yield is 81%. The mass spectrometry analysis result m / z [H + ]=724.

[0165] The synthesis method of compound M16 refers to the synthesis steps of compound M8, wherein intermediate 16-5 replaces compound 8-5 in the synthesis method of compound M8, and compound 16-6 replaces compound 8-6 in the synthesis method of compound M8 to obtain intermediate M16. The yield is 80%. The mass spectrometry analysis result m / z [H + ]=813.

[0166] (17) Synthesis of Compound M17:

[0167]

[0168] The synthesis method of intermediate 17-3 refers to the synthesis operation steps of intermediate 2-3, wherein compound 17-1 replaces compound 2-1 in the synthesis method of intermediate 2-3, and compound 17-2 replaces compound 2-2 in the synthesis method of intermediate 2-3 to obtain intermediate 17-3. The yield is 85%. The mass spectrometry analysis result m / z [H + ]=669.

[0169] The synthesis method of intermediate 17-5 refers to the synthesis operation steps of the above-mentioned compound M1, wherein intermediate 17-3 replaces compound 1-2 in the synthesis method of compound M1, and compound 17-4 replaces compound 1-1 in the synthesis method of compound M1 to obtain intermediate M17-5. The yield is 83%. The mass spectrometry analysis result m / z [H + ]=878.

[0170] The synthesis method of compound M17 refers to the synthesis steps of compound M8, wherein intermediate 17-5 replaces compound 8-5 in the synthesis method of compound M8, and compound 17-6 replaces compound 8-6 in the synthesis method of compound M8 to obtain intermediate M17. The yield is 82%. The mass spectrometry analysis result m / z [H + ]=1087.

[0171] (18) Synthesis of Compound M18:

[0172]

[0173] The synthesis method of intermediate 18-3 refers to the synthesis operation steps of intermediate 2-3, wherein compound 18-1 replaces compound 2-1 in the synthesis method of intermediate 2-3, and compound 18-2 replaces compound 2-2 in the synthesis method of intermediate 2-3 to obtain intermediate 18-3. The yield is 82%. The mass spectrometry analysis result m / z [H + ]=577.

[0174] The synthesis method of intermediate 18-5 refers to the synthesis operation steps of the above-mentioned compound M1, wherein intermediate 18-3 replaces compound 1-2 in the synthesis method of compound M1, and compound 18-4 replaces compound 1-1 in the synthesis method of compound M1 to obtain intermediate M18-5. The yield is 86%. The mass spectrometry analysis result m / z [H + ]=786.

[0175] The synthesis method of compound M18 refers to the synthetic operation steps of compound M8 above, wherein intermediate 18-5 replaces compound 8-5 in the synthetic method of compound M8, and compound 18-6 replaces compound 8-6 in the synthetic method of compound M8 to obtain intermediate M18 with a yield of 81%. The mass spectrometry analysis result m / z [H + ]=949.

[0176] 2. Energy level test of organic compounds

[0177] The energy levels of organic compound materials can be determined through quantum calculations, such as using TD-DFT (time-dependent density functional theory) with Gaussian09W (Gaussian Inc.). For detailed simulation methods, see WO2011141110. The molecular geometry is first optimized using the semi-empirical method "Ground State / DFT / Default Spin / B3LYP / 6-31G(d)" (Charge 0 / Spin Singlet). The energy structure of the organic molecule is then calculated using the TD-DFT (time-dependent density functional theory) method using the "TD-SCF / DFT / Default Spin / B3PW91" basis set and the "6-31G(d)" (Charge 0 / Spin Singlet) basis set. The test results for compounds M1-M18 and the comparative compound Ref-01 using this method are shown in Table 1.

[0178] Table 1

[0179]

[0180]

[0181] As can be seen from the data in Table 1, compared with the reference compound Ref-01, the first singlet excited state energy level S1 of the compounds M1 to M18 of the present application is higher. The reason is that the unique connection mode between the nitrogen atom and the phenyl group of the phthalimide in the compounds M1 to M18 of the present application can weaken the degree of intermolecular conjugation, which helps the organic compounds of the present application to obtain a higher first singlet excited state energy level.

[0182] 3. Preparation of organic light-emitting devices

[0183] Example 1

[0184] (1) Structure of the organic light-emitting device 1:

[0185] The organic light-emitting device 1 includes a driving substrate, a first electrode (anode) (Ag (100 nm)), a hole injection layer (HT:P-1=97:3 (mass ratio), thickness 10 nm), a hole transport layer (HT, thickness 117 nm), an electron blocking layer (EB, thickness 10 nm), a light-emitting layer (BH:BD=97:3 (mass ratio), thickness 20 nm), a hole blocking layer (HB, thickness 8 nm), an electron transport layer (ET:Alq3=1:1 (mass ratio), thickness 30 nm), an electron injection layer (LiF, thickness 1 nm), a second electrode (cathode) layer (Mg:Ag=1:9 (mass ratio), thickness 16 nm), a first sub-covering layer (compound M1, thickness 15 nm), and a second sub-covering layer (CPL2-1, thickness 50 nm) stacked in sequence.

[0186] (2) Method for manufacturing organic light-emitting device 1:

[0187] First, a drive substrate layer is provided, a first electrode (anode) is formed on the drive substrate, and the first electrode is washed, i.e., sequentially washed with alkaline, washed with pure water, dried, and then washed with ultraviolet light and ozone to remove organic residues on the surface of the anode layer. The drive substrate layer is made of transparent glass, and the first electrode is made of Ag with a thickness of 100 nm.

[0188] Secondly, using a vacuum evaporation device, HT and P-1 materials are evaporated on the first electrode to form a hole injection layer with a thickness of 10 nm, and the mass ratio of HT to P-1 is 97:3; then HT material is evaporated on the hole injection layer to form a hole transport layer with a thickness of 117 nm; then EB material is evaporated on the hole transport layer to form an electron blocking layer with a thickness of 10 nm; then BH and BD materials are evaporated on the electron blocking layer to form a light-emitting layer, wherein BH is used as the main material and BD is used as the doping material, the doping ratio of the doping material is 3% by weight, and the light-emitting layer has a thickness of 20 nm; then HB material is evaporated on the light-emitting layer to form a hole blocking layer with a thickness of 8 nm; then ET and Alq3 materials are evaporated on the hole blocking layer to form an electron transport layer with a thickness of 30 nm, and the mass ratio of ET to Alq3 is 1:1; finally, LiF material is evaporated on the electron transport layer to form an electron injection layer with a thickness of 1 nm;

[0189] Then, Mg and Ag materials were evaporated on the electron injection layer to form the second electrode (cathode). The film thickness was 16 nm, and the mass ratio of Mg to Ag was 1:9.

[0190] Finally, compound M1 is evaporated on the second electrode to form a first sub-covering layer with a thickness of 15 nm; then CPL2-1 is evaporated on the first sub-covering layer to form a second sub-covering layer with a thickness of 50 nm.

[0191] Example 2

[0192] The structure and manufacturing method of the organic light-emitting device 2 refer to the structure and manufacturing method of the organic light-emitting device 1 in Example 1, with the only difference being that the material of the first sub-covering layer of the organic light-emitting device 2 adopts compound M2, and the other structures and materials of the organic light-emitting device 2 are the same as those of the organic light-emitting device 1.

[0193] Example 3

[0194] The structure and manufacturing method of the organic light-emitting device 3 refer to the structure and manufacturing method of the organic light-emitting device 1 in Example 1, with the only difference being that the material of the first sub-covering layer of the organic light-emitting device 3 adopts compound M3, and the other structures and materials of the organic light-emitting device 3 are the same as those of the organic light-emitting device 1.

[0195] Example 4

[0196] The structure and manufacturing method of the organic light-emitting device 4 refer to the structure and manufacturing method of the organic light-emitting device 1 in Example 1, with the only difference being that the material of the first sub-covering layer of the organic light-emitting device 4 adopts compound M4, and the other structures and materials of the organic light-emitting device 4 are the same as those of the organic light-emitting device 1.

[0197] Example 5

[0198] The structure and manufacturing method of the organic light-emitting device 5 refer to the structure and manufacturing method of the organic light-emitting device 1 in Example 1, with the only difference being that the material of the first sub-covering layer of the organic light-emitting device 5 adopts compound M5, and the other structures and materials of the organic light-emitting device 5 are the same as those of the organic light-emitting device 1.

[0199] Example 6

[0200] The structure and manufacturing method of the organic light-emitting device 6 refer to the structure and manufacturing method of the organic light-emitting device 1 in Example 1, with the only difference being that the material of the first sub-covering layer of the organic light-emitting device 6 adopts compound M6, and the other structures and materials of the organic light-emitting device 6 are the same as those of the organic light-emitting device 1.

[0201] Example 7

[0202] The structure and manufacturing method of the organic light-emitting device 7 refer to the structure and manufacturing method of the organic light-emitting device 1 in Example 1, with the only difference being that the material of the first sub-covering layer of the organic light-emitting device 7 adopts compound M7, and the other structures and materials of the organic light-emitting device 7 are the same as those of the organic light-emitting device 1.

[0203] Example 8

[0204] The structure and manufacturing method of the organic light-emitting device 8 refer to the structure and manufacturing method of the organic light-emitting device 1 in Example 1, with the only difference being that the material of the first sub-covering layer of the organic light-emitting device 8 adopts compound M8, and the other structures and materials of the organic light-emitting device 8 are the same as those of the organic light-emitting device 1.

[0205] Example 9

[0206] The structure and manufacturing method of the organic light-emitting device 9 refer to the structure and manufacturing method of the organic light-emitting device 1 in Example 1, with the only difference being that the material of the first sub-covering layer of the organic light-emitting device 9 adopts compound M9, and the other structures and materials of the organic light-emitting device 9 are the same as those of the organic light-emitting device 1.

[0207] Example 10

[0208] The structure and manufacturing method of the organic light-emitting device 10 refer to the structure and manufacturing method of the organic light-emitting device 1 in Example 1, with the only difference being that the material of the first sub-covering layer of the organic light-emitting device 10 adopts compound M10, and the other structures and materials of the organic light-emitting device 10 are the same as those of the organic light-emitting device 1.

[0209] Example 11

[0210] The structure and manufacturing method of the organic light-emitting device 11 refer to the structure and manufacturing method of the organic light-emitting device 1 in Example 1, with the only difference being that the material of the first sub-covering layer of the organic light-emitting device 11 adopts compound M11, and the other structures and materials of the organic light-emitting device 11 are the same as those of the organic light-emitting device 1.

[0211] Example 12

[0212] The structure and manufacturing method of the organic light-emitting device 12 refer to the structure and manufacturing method of the organic light-emitting device 1 in Example 1, with the only difference being that the material of the first sub-covering layer of the organic light-emitting device 12 adopts compound M12, and the other structures and materials of the organic light-emitting device 12 are the same as those of the organic light-emitting device 1.

[0213] Example 13

[0214] The structure and manufacturing method of the organic light-emitting device 13 refer to the structure and manufacturing method of the organic light-emitting device 1 in Example 1, with the only difference being that the material of the first sub-covering layer of the organic light-emitting device 13 adopts compound M13, and the other structures and materials of the organic light-emitting device 13 are the same as those of the organic light-emitting device 1.

[0215] Example 14

[0216] The structure and manufacturing method of the organic light-emitting device 14 refer to the structure and manufacturing method of the organic light-emitting device 1 in Example 1, with the only difference being that the material of the first sub-covering layer of the organic light-emitting device 14 adopts compound M14, and the other structures and materials of the organic light-emitting device 14 are the same as those of the organic light-emitting device 1.

[0217] Example 15

[0218] The structure and manufacturing method of the organic light-emitting device 15 refer to the structure and manufacturing method of the organic light-emitting device 1 in Example 1, with the only difference being that the material of the first sub-covering layer of the organic light-emitting device 15 adopts compound M15, and the other structures and materials of the organic light-emitting device 15 are the same as those of the organic light-emitting device 1.

[0219] Example 16

[0220] The structure and manufacturing method of the organic light-emitting device 16 refer to the structure and manufacturing method of the organic light-emitting device 1 in Example 1, with the only difference being that the material of the first sub-covering layer of the organic light-emitting device 16 adopts compound M16, and the other structures and materials of the organic light-emitting device 16 are the same as those of the organic light-emitting device 1.

[0221] Example 17

[0222] The structure and manufacturing method of the organic light-emitting device 17 refer to the structure and manufacturing method of the organic light-emitting device 1 in Example 1, with the only difference being that the material of the first sub-covering layer of the organic light-emitting device 17 adopts compound M17, and the other structures and materials of the organic light-emitting device 17 are the same as those of the organic light-emitting device 1.

[0223] Example 18

[0224] The structure and manufacturing method of the organic light-emitting device 18 refer to the structure and manufacturing method of the organic light-emitting device 1 in Example 1, with the only difference being that the material of the first sub-covering layer of the organic light-emitting device 18 adopts compound M18, and the other structures and materials of the organic light-emitting device 18 are the same as those of the organic light-emitting device 1.

[0225] Comparative Example 1

[0226] The structure and manufacturing method of the organic light-emitting device 19 refer to the structure and manufacturing method of the organic light-emitting device 1 in Example 1, with the only difference being that the organic light-emitting device 19 includes only a first sub-covering layer but no second sub-covering layer, and the material of the first sub-covering layer is compound M1. The other structures and materials of the organic light-emitting device 19 are the same as those of the organic light-emitting device 1.

[0227] Comparative Example 2

[0228] The structure and manufacturing method of the organic light-emitting device 20 refer to the structure and manufacturing method of the organic light-emitting device 1 in Example 1, with the only difference being that the organic light-emitting device 20 only includes a second sub-covering layer but no first sub-covering layer, and the material of the second sub-covering layer is compound CPL2-1. The other structures and materials of the organic light-emitting device 20 are the same as those of the organic light-emitting device 1.

[0229] Comparative Example 3

[0230] The structure and manufacturing method of the organic light-emitting device 21 refer to the structure and manufacturing method of the organic light-emitting device 1 in Example 1, with the only difference being that the material of the first sub-covering layer of the organic light-emitting device 21 adopts compound Ref-01, and the other structures and materials of the organic light-emitting device 21 are the same as those of the organic light-emitting device 1.

[0231] Description of the materials, equipment and testing methods used in the examples of this application:

[0232] Source of materials: Some raw materials were purchased commercially or synthesized with reference to prior art literature. The molecular structures of the relevant materials involved in the examples of this application are shown below:

[0233]

[0234] Test equipment: vacuum evaporation device, 200*200mm evaporation equipment from Choshu Industry, Japan.

[0235] Test method: Using the IVL (current-voltage-luminance) test system (Suzhou Fushida Scientific Instrument Co., Ltd.), select the software EILV20060707 to test the IVL characteristic curves and efficiency vs. current density curves of OLEDs 1 to 21. 2 The data under the conditions shall prevail (i.e. the test current density reaches 10mA / cm 2 The test results of the above organic light-emitting devices are shown in Table 2:

[0236] Table 2

[0237]

[0238]

[0239]

[0240] Here, n1 represents the refractive index of the first sub-covering layer for light with a wavelength of 460 nm, and n2 represents the refractive index of the second sub-covering layer for light with a wavelength of 460 nm.

[0241] It can be seen from the results of Example 1 and Comparative Examples 1 and 2 that the luminous efficiency of the organic light-emitting device 1 is higher than the luminous efficiency of the organic light-emitting device 19 and the luminous efficiency of the organic light-emitting device 20, indicating that when only a single high-refractive index or low-refractive index covering layer is used, the luminous efficiency of the organic light-emitting device is poor, while when a combination of high-refractive index and low-refractive index covering layers is used, the luminous efficiency of the organic light-emitting device is significantly improved.

[0242] It can be seen from the results of Examples 1 to 18 and Comparative Example 3 that the luminous efficiency of the organic light-emitting devices 1 to 18 is higher than that of the organic light-emitting device 21, that is, when the material of the second sub-covering layer with a high refractive index is maintained unchanged, when the organic compound of the present application is used to prepare the first sub-covering layer with a low refractive index, the luminous efficiency of the organic light-emitting device can be significantly improved.

[0243] In summary, the organic compound represented by formula (1) of the present application can be used to prepare a low-refractive-index covering layer having a relatively high first singlet excited state energy level. When the low-refractive-index covering layer is used in combination with a high-refractive-index covering layer to form a covering layer structure of an organic light-emitting device, the luminous efficiency of the organic light-emitting device can be effectively enhanced.

[0244] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0245] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0246] The embodiments, implementation methods and related technical features of the present application can be combined and replaced with each other without conflict.

[0247] The above are merely preferred embodiments of the present application and do not constitute any form of limitation to the present application. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. An organic compound, characterized in that The organic compound has a structure represented by general formula (1): in, R1, R2 and R3 are at least one selected from hydrogen, fluorine, a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, and a substituted or unsubstituted aromatic group having 6 to 30 carbon atoms; n1 is any integer selected from 0, 1, 2, 3, 4, and 5; n2 is any integer selected from 0, 1, 2, 3, 4, 5; n3 is any integer selected from 0, 1, 2, 3, and 4.

2. The organic compound according to claim 1, characterized in that When R1, R2 and R3 are selected from substituted alkyl groups or substituted aromatic groups, the substituents are selected from fluorine-containing groups.

3. The organic compound according to claim 1, characterized in that R1, R2 and R3 are selected from hydrogen, fluorine, trifluoromethyl, fluorine-substituted phenyl, fluorine-substituted biphenyl, trifluoromethyl-substituted phenyl, trifluoromethyl-substituted biphenyl.

4. The organic compound according to claim 1, characterized in that The organic compound is selected from any one of the following structures:

5. An organic light-emitting device, characterized in that: include: a first electrode; a light-emitting functional layer, disposed on the first electrode; a second electrode, disposed on a side of the light-emitting functional layer away from the first electrode; as well as a covering layer, disposed on a side of the second electrode away from the light-emitting functional layer; The material of the covering layer comprises at least one organic compound according to any one of claims 1 to 4.

6. The organic light-emitting device according to claim 5, characterized in that: The covering layer includes a first sub-covering layer and a second sub-covering layer, wherein the first sub-covering layer is located between the second electrode and the second sub-covering layer; The material of the first sub-covering layer includes at least one organic compound, and the refractive index of the first sub-covering layer is smaller than the refractive index of the second sub-covering layer.

7. The organic light-emitting device according to claim 6, characterized in that: The refractive index of the first sub-cover layer is less than or equal to 1.65, and the refractive index of the second sub-cover layer is greater than or equal to 1.

85.

8. The organic light-emitting device according to claim 6, wherein: A difference between a refractive index of the first sub-cover layer and a refractive index of the second sub-cover layer is greater than or equal to 0.

3.

9. The organic light-emitting device according to claim 6, wherein: The optical band gap E of the organic compound in the first sub-covering layer g Greater than 3.0eV.

10. A display device, characterized in that: The organic light-emitting device according to any one of claims 5 to 9 is included.

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