Organic compound, organic light emitting device, and display apparatus

Abstract

The application 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): (1); the organic compound represented by the formula (1) has a low refractive index, can be used for forming a cover layer with a low refractive index, and when the low refractive index cover layer and a high refractive index cover layer are used to form a cover layer structure of the organic light-emitting device, the luminous efficiency of the organic light-emitting device can be obviously improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to an organic compound, an organic light emitting device and a display device. BACKGROUND

[0002] Organic Light Emitting Diode (OLED) devices are favored in many application fields such as main display screens due to their excellent display performance, and have made significant progress in the process of practical application. However, although the organic electroluminescence technology develops rapidly, it still faces many challenges, especially the demand for improving the external quantum efficiency (EQE). For OLED devices, the light-emitting quantum efficiency is not only a comprehensive embodiment of the performance of the device, but also a key standard for measuring the quality of the device.

[0003] In the related art, the light extraction efficiency of the OLED device is optimized by a capping layer (CPL). However, the organic material currently used for the capping layer generally has the problem of low light extraction efficiency, which limits the improvement of the light-emitting efficiency of the OLED device. SUMMARY

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

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

[0006] (1)

[0007] wherein,

[0008] R is independently selected from at least one of hydrogen, fluorine, a substituted or unsubstituted alkyl group, and a substituted or unsubstituted aromatic group.

[0009] In some embodiments, when R is selected from a substituted alkyl group or a substituted aromatic group, the substituent group is selected from an alkyl group or a fluorine-containing group.

[0010] In some embodiments, R is selected from at least one of hydrogen, fluorine, a methyl group, a trifluoromethyl group, a fluorine-substituted phenyl group, a methyl-substituted phenyl group, and a trifluoromethyl-substituted phenyl group.

[0011] In some embodiments, the organic compound is selected from any one of the following structures: .

[0012] In some embodiments, the organic compound has a refractive index ranging from 1.40 to 1.70 for light having a wavelength of 460 nm.

[0013] The present application also provides an organic light-emitting device, comprising:

[0014] a first electrode;

[0015] a light-emitting functional layer disposed on the first electrode;

[0016] a second electrode disposed on a side of the light-emitting functional layer away from the first electrode; and

[0017] a cover layer disposed on a side of the second electrode away from the light-emitting functional layer.

[0018] The material of the cover layer comprises at least one organic compound as described above.

[0019] In some embodiments, the cover layer comprises a first sub-cover layer and a second sub-cover layer, the first sub-cover layer being located between the second electrode and the second sub-cover layer.

[0020] The first sub-cover layer has a refractive index less than a refractive index of the second sub-cover layer.

[0021] In some embodiments, the first sub-cover layer has a refractive index for light with a wavelength of 460 nm less than or equal to 1.60, and the second sub-cover layer has a refractive index for light with a wavelength of 460 nm greater than or equal to 1.85.

[0022] In some embodiments, the second sub-cover layer has a refractive index for light with a wavelength of 460 nm greater than or equal to 0.3 more than a refractive index for light with a wavelength of 460 nm of the first sub-cover layer.

[0023] In some embodiments, the first sub-cover layer has a refractive index for light with a wavelength of 460 nm less than or equal to 0.3 less than a refractive index for light with a wavelength of 620 nm of the first sub-cover layer.

[0024] The present application also provides a display device comprising the organic light-emitting device as described above.

[0025] The present application provides an organic compound, an organic light-emitting device and a display device. In the organic compound of the present application, two arylamine structures are connected by a diphenylpropane structure, and the two benzene rings are connected by a structure similar to propane [-CH-(CH3)2], so that the conjugated system is interrupted, and the degree of overall pi electron delocalization is much lower than that of a fused ring or a conjugated polymer. Therefore, the electron cloud has a weak response to an applied electric field, and the macroscopic performance is a low refractive index. In addition, the methyl and methylene in the propane bridge are in a tetrahedral configuration, so that the whole molecule is "bent" rather than planar stacking. After crystallization or evaporation to form a film, a large amount of free volume can still be retained. Such low density results in a small number of polarizable particles per unit volume, which synergistically contributes to a low refractive index. Therefore, the organic compound of the present application has a low refractive index, and can be used to form a low refractive index cover layer. When the low refractive index cover layer is combined with a high refractive index cover layer to form a cover layer structure and applied to an organic light-emitting device, the luminous efficiency of the device can be significantly improved. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0027] Figure 1 is a structural schematic diagram of an organic light-emitting device provided by an embodiment of the present application;

[0028] Figure 2 is a structural schematic diagram of another organic light-emitting device provided by an embodiment of the present application.

[0029] Figure 3 is a nuclear magnetic hydrogen spectrum of compound M4 provided by an embodiment of the present application.

[0030] Legend of reference signs:

[0031] 100 – organic light-emitting device; 110 – driving substrate; 120 – first electrode; 130 – light-emitting functional layer; 131 – hole injection layer; 132 – hole transport layer; 133 – electron blocking layer; 134 – light-emitting layer; 135 – hole blocking layer; 136 – electron transport layer; 137 – electron injection layer; 140 – second electrode; 150 – cover layer; 151 – first sub-cover layer; 152 – second sub-cover layer; 160 – protection layer; 170 – encapsulation layer. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0033] In the present application, “n@460 nm” refers to the refractive index of the material relative to vacuum for blue light of 460 nm wavelength; “n@525 nm” refers to the refractive index of the material relative to vacuum for green light of 530 nm wavelength; “n@620 nm” refers to the refractive index of the material relative to vacuum for red light of 620 nm wavelength.

[0034] The present application provides an organic compound, which has a structure represented by general formula (1):

[0035] (1)

[0036] wherein,

[0037] R is independently selected at each occurrence from at least one of hydrogen, fluorine, a substituted or unsubstituted alkyl group, and a substituted or unsubstituted aromatic group;

[0038] It should be noted that in the structure represented by general formula (1), R at different positions can be selected from the same group or different groups.

[0039] In some embodiments, R is selected from at least one of hydrogen, fluorine, an alkyl group having 1 to 5 carbon atoms and being substituted or unsubstituted, and an aromatic group having 6 to 30 carbon atoms and being substituted or unsubstituted.

[0040] In some embodiments, when R is selected from a substituted alkyl or a substituted aromatic group, the substituent is selected from an alkyl or a fluorinated group.

[0041] Furthermore, the substituent is selected from at least one of fluorine, alkyl groups having 1 to 5 carbon atoms, and fluorine-substituted alkyl groups having 1 to 5 carbon atoms.

[0042] In some embodiments, R is selected from at least one of hydrogen, fluorine, methyl, trifluoromethyl, fluorine-substituted phenyl, methyl-substituted phenyl, and trifluoromethyl-substituted phenyl.

[0043] In some embodiments, the organic compound is selected from any of the following structures: .

[0044] In some embodiments, the organic compound has a low refractive index, specifically a refractive index ranging from 1.40 to 1.70 for light with a wavelength of 460 nm (blue light); preferably, the refractive index range of the organic compound for light with a wavelength of 460 nm is 1.40 to 1.60. For example, the refractive index of the organic compound for light with a wavelength of 460 nm may be 1.40, 1.45, 1.50, 1.55, or 1.60, but is not limited thereto.

[0045] In this application, the two aromatic amine structures in the organic compound represented by general formula (1) are connected by a diphenylpropane structure, wherein the two benzene rings are connected by a structure similar to propane [-CH-(CH3)2], which isolates the conjugated system. The overall π electron delocalization degree is much lower than that of fused rings or conjugated polymers. Therefore, the electron cloud has a weaker response to the applied electric field, which macroscopically manifests as a lower refractive index. In addition, the methyl and methylene groups in the propane bridge have a tetrahedral configuration, which makes the molecule "bent" rather than planar stacked. After crystallization or vapor deposition, a large amount of free volume can still be retained. Such low density results in fewer polarizable particles per unit volume, which synergistically contributes to obtaining a lower refractive index. Therefore, the organic compound of this application has a low refractive index and can be used to form a low refractive index capping layer. When the low refractive index capping layer using this organic compound is combined with a high refractive index capping layer and applied to organic light-emitting devices, the luminous efficiency of organic light-emitting devices can be significantly improved.

[0046] 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 capping layer 150. The light-emitting functional layer 130 is disposed on the first electrode 120; the second electrode 140 is disposed on the side of the light-emitting functional layer 130 away from the first electrode 120; and the capping layer 150 is disposed on the side of the second electrode 140 away from the light-emitting functional layer 130. The material of the capping layer 150 includes at least one organic compound represented by formula (1) as described above. This application uses the organic compound represented by formula (1) to form the capping layer, which can significantly improve the light extraction efficiency of the capping layer, thereby improving the luminous efficiency of the organic light-emitting device.

[0047] In some embodiments, please refer to Figure 1 The organic light-emitting device 100 also includes a driving substrate 110, which is disposed on the 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.

[0048] The driving substrate includes a substrate and a driving circuit disposed on the substrate. The substrate can be glass or a flexible polyimide film; it can be a transparent plastic substrate or an opaque material substrate, such as silicon or stainless steel, but is not limited thereto. The driving circuit includes thin-film transistors, capacitors, wires, etc. Different driving substrates have different mechanical strengths, thermal stability, transparency, surface smoothness, and water resistance. Depending on the properties of the driving substrate, its application will differ, and the specific choice can be made according to the performance requirements of the organic light-emitting device; this application does not impose any restrictions.

[0049] In this 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.

[0050] In some embodiments, the first electrode can be a reflective electrode, such as a reflective film formed of silver (Ag), magnesium (Mg), aluminum (Al), gold (Au), nickel (Ni), chromium (Cr) or their alloys; 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 high work function formed on the reflective film, wherein the transparent or semi-transparent electrode layer can be formed of 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), or it can be composed of a combination of metal and oxide, such as ITO / Ag / ITO, IGO / Al / IGO or AZO / Ag / AZO. Light emitted from the light-emitting functional layer can be reflected from the first electrode to the second electrode, and then emitted from the second electrode. The first electrode can be formed by methods such as sputtering, ion plating, vacuum evaporation, spin coating, electron beam evaporation, or chemical vapor deposition (CVD), with sputtering being the preferred method. The thickness of the first electrode layer depends on the material used, and the thickness ranges from 5 nm to 1 μm, preferably 10 nm to 1 μm, more preferably 10 nm to 500 nm, particularly preferably 10 nm to 300 nm, and most preferably 10 nm to 200 nm.

[0051] In some embodiments, the second electrode can be a transparent or semi-transparent electrode, for example, a thin film with low work function made of lithium, calcium, lithium fluoride / calcium, lithium fluoride / aluminum, aluminum, silver, magnesium, or alloys thereof. Further, the second electrode layer can be made of an alloy including silver and at least one metal, said 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, greater than, or less than the weight ratio of the other metals. For example, the second electrode layer can be formed of a silver-magnesium alloy, wherein the mass ratio of silver to magnesium can be 90:10 to 10:90. Alternatively, the second electrode layer can be formed of an alloy including 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. The film formed from these metals can be made transparent or semi-transparent 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.

[0052] In this 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. The thickness of the light-emitting functional layer ranges from 50 nm to 1000 nm.

[0053] In some embodiments, the light-emitting functional layer may consist of only the light-emitting layer.

[0054] In some embodiments, when the light-emitting functional layer comprises multiple film layers, the light-emitting functional layer may include, in addition to the light-emitting layer, at least one of a hole transport layer, a hole injection layer, an electron blocking layer, an electron transport layer, and an electron injection layer. When the first electrode is an anode and the second electrode is a cathode, a hole transport region is formed between the first electrode and the light-emitting layer, and an electron transport region is formed between the second electrode and the light-emitting layer; wherein, the space between the first electrode and the light-emitting layer may include at least one of a hole injection layer, a hole transport layer, and an electron blocking layer, and the space between the second electrode and the light-emitting layer may include at least one of a hole blocking layer, an electron transport layer, and an electron injection layer. When the first electrode is a cathode and the second electrode is an anode, an electron transport region is formed between the first electrode and the light-emitting layer, and a hole transport region is formed between the second electrode and the light-emitting layer; wherein, the space between the first electrode and the light-emitting layer may include at least one of a hole blocking layer, an electron transport layer, and an electron injection layer, and the space between the second electrode and the light-emitting layer may include at least one of a hole injection layer, a hole transport layer, and an electron blocking layer.

[0055] For details, please refer to Figure 2Taking 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. 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.

[0056] In some embodiments, the light-emitting functional layer can be formed from small-molecule organic materials or polymeric materials. The light-emitting functional layer can be formed by methods such as vacuum evaporation, solution spin coating, screen printing, or inkjet printing.

[0057] In some embodiments, the material of the light-emitting layer may include a host material and a dopant material. The host material needs to possess bipolar charge transport characteristics and an appropriate energy level to effectively transfer the excitation energy generated by electron-hole recombination to the guest light-emitting material, i.e., the dopant material. The host material may be a stilbene arylene derivative, a stilbene derivative, a carbazole derivative, a triarylamine derivative, anthracene derivative, a pyrene derivative, a triazine derivative, an oxanthone derivative, a triphenylene derivative, a triazine derivative, a hexabenzobenzene derivative, or bis(2-methyl-8-quinoline)(p-phenylphenol)aluminum (BAlq), etc.; the dopant material may be a fluorescent material, a delayed fluorescence (TADF) material, or a phosphorescent material, etc.

[0058] In some embodiments, in order to improve the luminous efficiency of organic light-emitting devices, the light-emitting layer may contain one or more doping materials. The doping materials may be one of fluorescent materials, delayed fluorescence (TADF) materials, or phosphorescent materials, or may be a combination of different fluorescent materials, delayed fluorescence (TADF) materials, or phosphorescent materials.

[0059] In some embodiments, the light-emitting layer may include one or more sub-light-emitting layers of different 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 comprises a red luminescent material, the green sub-light-emitting layer comprises a green luminescent material, and the blue sub-light-emitting layer comprises a blue luminescent material. To regulate the effective binding of charge carriers in the light-emitting layer, the film thickness of the light-emitting layer can be arbitrarily adjusted as needed, or different light-emitting layers can be alternately stacked and combined as needed. Furthermore, charge-blocking layers with different functional purposes can be added between adjacent light-emitting layers.

[0060] In some embodiments, the light-emitting layer may be a single light-emitting material layer or a composite light-emitting material layer stacked together laterally or vertically. The light-emitting layer may be selected from the following structures: (1) a single light-emitting material layer; (2) a combination of a blue light-emitting material layer and any one of a green, yellow or red light-emitting material layer, regardless of the order; (3) a combination of a blue light-emitting material layer and any two of a green, yellow or red light-emitting material layer, regardless of the order; (4) a blue light-emitting material layer, a green light-emitting material layer, and a red light-emitting material layer arranged laterally.

[0061] In some embodiments, the materials for the hole injection layer, hole transport layer, and electron blocking layer can be selected from any known materials used in OLED organic light-emitting devices.

[0062] In some embodiments, at least one of the hole injection layer and the hole transport layer may further include a charge-generating material for improving conductivity. The charge-generating material may be a p-dopant, which may be: a quinone derivative, such as tetracyanoquinone dimethyl (TCNQ) and 2,3,5,6-tetrafluoro-tetracyano-1,4-benzoquinone dimethyl (F4-TCNQ); or a hexaazatriphenyl derivative, such as 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenyl (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 is not limited thereto.

[0063] In some embodiments, the triplet (T1) energy level of the electron blocking layer material is higher than the T1 energy level of the host material in the emissive layer, thus blocking energy loss from the emissive 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 host material of the emissive layer, facilitating hole injection from the anode into the emissive layer. Simultaneously, the electron blocking layer material is required to have high hole mobility to facilitate hole transport and reduce the power consumption 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 host material of the emissive layer, thus providing electron blocking; that is, the electron blocking layer material is required to have a wide bandgap (Eg). Specifically, the electron blocking layer material can be a triarylamine derivative, fluorene derivative, spirofluorene derivative, dibenzofuran derivative, or carbazole derivative, etc. Preferred of these are triarylamine derivatives, such as N4,N4-bis([1,1'-biphenyl]-4-yl)-N4'-phenylN4'-[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'-spirodifluorene-2-amine; and 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 not limited thereto.

[0064] In some embodiments, the hole blocking layer and the electron transport layer are made of materials with electron transport properties, and any material can be selected from known materials used in OLED organic light-emitting devices. Materials possessing electron transport properties can be oxadiazole derivatives such as 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, triazole derivatives such as 3-(4'-tert-butylphenyl)-4-phenyl-5-(4”-biphenyl)-1,2,4-triazole, triazine derivatives, quinoline derivatives, quinoxaline derivatives, dibenzoquinone derivatives, nitro-substituted linone derivatives, thiam dioxide derivatives, anthraquinone dimethane derivatives, thiam dioxide derivatives, heterocyclic tetrahydric anhydrides such as naphthylperylene, carbodiimide, lin derivatives, anthraquinone dimethane derivatives, anthrone derivatives, stilbene pyrazine derivatives, silyrocyclopentadiene derivatives, diazonium phenanthrene derivatives, or imidazopyridine derivatives, etc.

[0065] In this application, the coating layer may be formed by an organic compound represented by formula (1), or by an organic compound represented by formula (1) and an organic compound with an aromatic amine structure. The coating layer may be formed by methods such as vacuum evaporation, solution spin coating, screen printing, or inkjet printing.

[0066] In some embodiments, please refer to Figure 1 The capping layer 150 includes a first sub-capping layer 151 and a second sub-capping layer 152. The first sub-capping layer 151 is located between the second electrode 140 and the second sub-capping layer 152. The refractive index of the first sub-capping layer 151 is less than that of the second sub-capping layer 152. The material of the first sub-capping layer 151 includes at least one organic compound represented by formula (1).

[0067] In some embodiments, the second sub-coating layer comprises a high-refractive-index organic compound. For example, the material of the second sub-coating layer may include at least one of, but is not limited to, the following compounds:

[0068] .

[0069] In this application, the capping layer is a double-capping layer structure composed of a first sub-capping layer with a low refractive index and a second sub-capping layer with a high refractive index. In this double-capping layer structure, due to the refractive index difference between the high-refractive-index second sub-capping layer and the low-refractive-index first sub-capping layer, part of the light emitted from the light-emitting functional layer passes through the capping layer, while the other part is reflected by it. The light reflection phenomenon is particularly pronounced at the interface between the high-refractive-index second sub-capping layer and the low-refractive-index first sub-capping layer, and at the interface between the high-refractive-index second sub-capping layer and the encapsulation layer above it. The light reflected by the capping layer is reflected again at the second electrode and enhanced during this repeated reflection process. Therefore, light can be repeatedly reflected at the interface between the high-refractive-index second sub-capping layer and the low-refractive-index first sub-capping layer, and at the interface between the high-refractive-index second sub-capping layer and the encapsulation layer above it, thereby recovering the light lost due to reflection away from the device surface. Thus, the double-capping layer structure composed of a low-refractive-index first sub-capping layer and a high-refractive-index second sub-capping layer is more conducive to improving light extraction efficiency and further enhancing the luminous efficiency of the organic light-emitting device.

[0070] The first sub-coating layer is formed by using the organic compound represented by formula (1), which enables the first sub-coating to obtain a lower refractive index. When combined with the second sub-coating layer with a high refractive index, it can significantly improve the overall light extraction efficiency of the coating layer.

[0071] In some embodiments, the refractive index of the first sub-capping layer at 460 nm is less than or equal to 1.60, preferably less than or equal to 1.55, and more preferably less than or equal to 1.50. The refractive index of the first sub-capping layer at 525 nm is less than or equal to 1.60, preferably less than or equal to 1.55, and more preferably less than or equal to 1.50. The refractive index of the first sub-capping layer at 620 nm is less than or equal to 1.60, preferably less than or equal to 1.55, and more preferably less than or equal to 1.50.

[0072] In some embodiments, the refractive index of the second sub-capping layer at 460 nm is greater than or equal to 1.85, preferably greater than or equal to 1.9, more preferably greater than or equal to 2.0, even more preferably greater than or equal to 2.1, still more 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-capping layer at 525 nm is greater than or equal to 1.85, preferably greater than or equal to 1.9, more preferably greater than or equal to 2.0, even more preferably greater than or equal to 2.1, and more preferably greater than or equal to 2.2. The refractive index of the second sub-capping layer at 620 nm is greater than or equal to 1.8, preferably greater than or equal to 1.9, more preferably greater than or equal to 2.0, and more preferably greater than or equal to 2.1.

[0073] In some embodiments, the difference between the refractive index of the first sub-coating layer for light with a wavelength of 460 nm and the refractive index of the second sub-coating layer for light with a wavelength of 460 nm can be greater than or equal to 0.3, preferably greater than or equal to 0.4, further preferably greater than or equal to 0.5, even more preferably greater than or equal to 0.6, even more preferably greater than or equal to 0.7, and more preferably greater than or equal to 0.8, so as to reduce total internal reflection of light at the interface and improve light extraction efficiency.

[0074] In some embodiments, the difference between the refractive index of the first sub-coating layer for light with a wavelength of 460 nm and the refractive index of the first sub-coating layer for light with a wavelength of 620 nm is less than or equal to 0.3, so as to make the light emission efficiency of different colors of light more balanced, thereby improving the overall luminous efficiency of the autoluminescent device.

[0075] In one embodiment, the refractive index of the first sub-coating layer is less than that of the second sub-coating layer. The refractive index of the first sub-coating layer for light with a wavelength of 460 nm is less than or equal to 1.60, and the refractive index of the second sub-coating layer for light with a wavelength of 460 nm is greater than or equal to 1.85. The difference between the refractive indices of the first and second sub-coating layers for light with a wavelength of 460 nm is greater than or equal to 0.3, thereby improving the light extraction efficiency.

[0076] In some embodiments, the optical band gap E of the organic compound in the first sub-coating layer gGreater than 3.0 eV, preferably greater than 3.5 eV. When the optical band gap E of the organic compound... g When the energy level is greater than the above range, it indicates that the material of the first sub-capping layer has a higher first singlet excited state energy level. In this case, the absorption of the first sub-capping layer in the visible light band is weaker. During the propagation of light in the device, the probability of the light being absorbed by the first sub-capping layer is lower, and it is easier to extract the light from the device, which is beneficial to improving the overall luminous efficiency of the electroluminescent device.

[0077] In some embodiments, the thickness of the capping layer ranges from 15 nm to 300 nm, preferably 30 nm to 200 nm, more preferably 40 nm to 100 nm, and most preferably 50 nm to 80 nm. The thickness of the first sub-capping layer ranges from 1 nm to 150 nm, preferably 5 nm to 100 nm, and more preferably 10 nm to 50 nm; the thickness of the second sub-capping layer ranges from 1 nm to 150 nm, preferably 10 nm to 100 nm, and more preferably 20 nm to 80 nm. The thicknesses of the first and second sub-capping layers may be the same or different.

[0078] In some embodiments, please refer to Figure 2 The organic light-emitting device 100 further includes a protective layer 160, which is disposed on the side of the capping layer 150 away from the light-emitting functional layer 130, for protecting the capping layer 150. The protective layer 160 can be an inorganic material, such as lithium fluoride (LiF), but is not limited thereto. The thickness of the protective layer 160 ranges from 20 nm to 400 nm, preferably 30 nm to 200 nm, and more preferably 40 nm to 100 nm. Specifically, the thickness of the protective layer 160 depends on the material used.

[0079] In some embodiments, please refer to Figure 2 The organic light-emitting device 100 also includes an encapsulation layer 170, which is disposed on the side of the protective layer 160 away from the cover layer 150 to cover the protective layer 160, the cover layer 150, and the light-emitting functional layer 130. The encapsulation layer 170 is used to prevent external substances such as moisture and oxygen from entering the organic layer of the organic light-emitting device, so as to avoid water and oxygen intrusion that may cause display abnormalities.

[0080] Furthermore, 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 stacked together, wherein the first encapsulation layer is an inorganic layer, the second encapsulation layer is an organic layer, and the third encapsulation layer is an inorganic layer; the material of the inorganic layer may be selected from Al2O3, SiO2, etc. x N y TiO2, SiO x and SiN xAt least one of the following, 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 chemical vapor deposition (CVD); the organic layer material can be an organic material known in the prior art for encapsulation layers of OLED organic light-emitting devices, for example, the organic layer material can be at least one of polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), polystyrene (PS), polymer derivatives having phenol groups, acrylic-based polymers, imide-based polymers, arylether-based polymers, amide-based polymers, fluorine-based polymers, p-xylene-based polymers, or vinyl alcohol-based polymers, the organic layer can be formed by curing the organic material by UV curing.

[0081] This application also provides a display device, which includes the organic light-emitting device described above. This display device can be used in smartphones, tablets, smart wearable devices, televisions, virtual reality (VR), microdisplays, and automotive central control screens, but is not limited thereto.

[0082] The organic compounds and organic light-emitting devices of this application are further illustrated by specific embodiments below, but this application is not limited to the following embodiments.

[0083] 1. Synthesis of organic compounds

[0084] (1) Synthesis of compound M1:

[0085]

[0086] Compound 1-1 (10 mmol), compound 1-2 (40 mmol), Pd2(dba)3 (0.2 mmol), X-phos (0.4 mmol), and sodium tert-butoxide (20 mmol) were dissolved in xylene and stirred at 140 °C for 13 h under a nitrogen atmosphere. After cooling the reaction mixture to room temperature, a portion of the solvent was removed using a rotary evaporator, followed by extraction three times with dichloromethane and water. The mixture was separated, dried over MgSO4, and filtered. The solvent was removed under reduced pressure. The crude product was purified by column chromatography to obtain compound M1 in 86% yield. Mass spectrometry m / z [H]+ = 602. Elemental analysis results show C, 77.75; H, 5.04; F, 12.62; N, 4.61.

[0087] (2) Synthesis of compound M2:

[0088]

[0089] The synthesis method for compound M2 is the same as that for compound M1 described above, with a yield of 84%. Mass spectrometry m / z [H] + =808. Elemental analysis results show C, 62.77; H, 2.95; F, 30.56; N, 3.77.

[0090] (3) Synthesis of compound M3:

[0091]

[0092] The synthesis method for compound M3 is the same as that for compound M1 described above, with a yield of 85%. Mass spectrometry m / z [H] + =802. Elemental analysis results show C, 64.35; H, 3.73; F, 28.44; N, 3.46.

[0093] (4) Synthesis of compound M4:

[0094]

[0095] The synthesis method for compound M4 was the same as that for compound M1 described above, with a yield of 82%. Mass spectrometry m / z [H] + =1074. Elemental analysis results: C, 52.55; H, 2.47; F, 42.42; N, 2.62. The 1H NMR spectrum of compound M4 is attached. Figure 3 .

[0096] (5) Synthesis of compound M5:

[0097]

[0098] The synthesis method for compound M5 was the same as that for compound M1 described above, with a yield of 84%. Mass spectrometry m / z [H] + =926. Elemental analysis results show C, 50.58; H, 1.32; F, 45.13; N, 3.05.

[0099] (6) Synthesis of compound M6:

[0100]

[0101] Synthesis of intermediate 6-3:

[0102] Compound 6-1 (10 mmol), compound 6-2 (10 mmol), Pd2(dba)3 (0.2 mmol), X-phos (0.4 mmol), and sodium tert-butoxide (20 mmol) were dissolved in toluene and stirred at 120 °C for 7 h under a nitrogen atmosphere. The reaction mixture was cooled to room temperature and then extracted three times with dichloromethane and water. After separation, the mixture was dried over MgSO4 and filtered. The solvent was removed under reduced pressure. The crude product was purified by column chromatography to obtain intermediate 6-3 in 87% yield. (Mass spectrometry m / z [H]) + =359.

[0103] Synthesis method of compound M6:

[0104] Compounds 6-3 (10 mmol), 6-4 (10 mmol), Pd2(dba)3 (0.2 mmol), X-phos (0.4 mmol), and sodium tert-butoxide (20 mmol) were dissolved in toluene and stirred at 120 °C for 13 h under a nitrogen atmosphere. The reaction mixture was cooled to room temperature and then extracted three times with dichloromethane and water. After separation, the mixture was dried over MgSO4 and filtered. The solvent was removed under reduced pressure. The crude product was purified by column chromatography to obtain compound M6 in 83% yield. Mass spectrometry m / z [H] + =359. Elemental analysis results showed C, 56.73; H, 2.67; F, 37.52; N, 3.06.

[0105] (7) Synthesis of compound M7:

[0106]

[0107] The synthesis method for intermediate 7-3 is the same as that for intermediate 6-3 described above, with a yield of 57%. Mass spectrometry m / z [H] + = 395.

[0108] The synthesis of compound M7 followed the same procedure as compound M6 described above, with a yield of 84%. Mass spectrometry m / z [H] + =982. Elemental analysis results: C, 52.58; H, 2.07; F, 42.52; N, 2.86.

[0109] (8) Synthesis of compound M8:

[0110]

[0111] The synthesis method for intermediate 8-3 is the same as that for intermediate 6-3 described above, with a yield of 67%. Mass spectrometry m / z [H] + =313.

[0112] The synthesis of compound M8 followed the same procedure as compound M6 described above, with a yield of 84%. Mass spectrometry m / z [H] + =818. Elemental analysis results show C, 57.27; H, 2.25; F, 37.11; N, 3.40.

[0113] (9) Synthesis of compound M9:

[0114]

[0115] The synthesis method for intermediate 9-3 is the same as that for intermediate 6-3 described above, with a yield of 78%. Mass spectrometry m / z [H] + = 517.

[0116] The synthesis of compound M9 followed the same procedure as compound M6 described above, with a yield of 83%. Mass spectrometry m / z [H] + =1226. Elemental analysis results show C, 57.78; H, 2.76; F, 37.18; N, 2.29.

[0117] (10) Synthesis of compound M10:

[0118]

[0119] The synthesis method for intermediate 10-3 is the same as that for intermediate 6-3 described above, with a yield of 74%. Mass spectrometry m / z [H] + = 517.

[0120] The synthesis of compound M10 followed the same procedure as compound M6 described above, with a yield of 86%. Mass spectrometry m / z [H] + =1226. Elemental analysis results show C, 57.76; H, 2.73; F, 37.16; N, 2.33.

[0121] (11) Synthesis of compound M11:

[0122]

[0123] The synthesis method for intermediate 11-3 is the same as that for intermediate 6-3 described above, with a yield of 79%. Mass spectrometry m / z [H] + = 517.

[0124] The synthesis of compound M11 followed the same procedure as compound M6 described above, with a yield of 83%. Mass spectrometry m / z [H] + =1362. Elemental analysis results show C, 53.75; H, 2.39; F, 41.85; N, 2.03.

[0125] (12) Synthesis of compound M12:

[0126]

[0127] Synthesis of intermediate 12-3:

[0128] Compound 12-1 (10 mmol), compound 12-2 (10 mmol), Pd(PPh3)4 (0.2 mmol), and potassium carbonate (30 mmol) were dissolved in a mixed solvent of dioxane and water, and stirred at 100 °C for 12 h under a nitrogen atmosphere. After cooling the reaction system to room temperature, a portion of the solvent was removed using a rotary evaporator, followed by extraction 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 intermediate 12-3 in 80% yield. Mass spectrometry m / z [H] + = 310.

[0129] The synthesis method for intermediate 12-5 is the same as that for intermediate 6-3 described above, with a yield of 79%. Mass spectrometry m / z [H] + = 503.

[0130] The synthesis of compound M12 followed the same procedure as compound M6 described above, with a yield of 86%. Mass spectrometry m / z [H] + =1198. Elemental analysis results show C, 57.13; H, 2.54; F, 38.05; N, 2.31.

[0131] (13) Synthesis of compound M13:

[0132]

[0133] Intermediate 13-1 is the same as intermediate 12-3.

[0134] The synthesis method of intermediate 13-3 is the same as that of intermediate 6-3 described above, with a yield of 83%. Mass spectrometry m / z [H] + = 421.

[0135] The synthesis of compound M13 followed the same procedure as compound M6 described above, with a yield of 86%. Mass spectrometry m / z [H] +=1034. Elemental analysis results show C, 61.54; H, 2.75; F, 33.01; N, 2.68.

[0136] (14) Synthesis of compound M14:

[0137]

[0138] The synthesis method for compound M14 was the same as that for compound M1, with a yield of 84%. Mass spectrometry m / z [H] + =642. Elemental analysis results show C, 87.85; H, 7.81; N, 4.38.

[0139] (15) Synthesis of compound M15:

[0140]

[0141] The synthesis method for compound M15 was the same as that for compound M1, with a yield of 84%. Mass spectrometry m / z [H] + =699. Elemental analysis results show C, 87.65; H, 8.37; N, 4.03.

[0142] (16) Synthesis of compound M16:

[0143]

[0144] The synthesis method for intermediate 16-3 is the same as that for intermediate 12-3 described above, with a yield of 75%. Mass spectrometry m / z [H] + = 298.

[0145] The synthesis method for intermediate 16-5 is the same as that for intermediate 12-5 described above, with a yield of 74%. Mass spectrometry m / z [H] + = 491.

[0146] The synthesis of compound M16 followed the same procedure as described above, with a yield of 83%. Mass spectrometry m / z [H] + =1175. Elemental analysis results show C, 64.43; H, 4.14; F, 29.12; N, 2.36.

[0147] 2. Fabrication of organic light-emitting devices

[0148] Example 1

[0149] (1) Structure of organic light-emitting device 1:

[0150] The organic light-emitting device 1 includes a driving substrate, a first electrode (anode) (Ag (100nm)), a hole injection layer (HT:PD=97:3 (mass ratio), 10nm thick), a hole transport layer (HT, 117nm thick), an electron blocking layer (EB, 10nm thick), a light-emitting layer (BH:BD=97:3 (mass ratio), 20nm thick), a hole blocking layer (HB, 8nm thick), an electron transport layer (ET:Liq=1:1 (mass ratio), 30nm thick), an electron injection layer (LiF, 1nm thick), a second electrode (cathode) layer (Mg:Ag=1:9 (mass ratio), 16nm thick), a first sub-capping layer (compound M1, 15nm thick), and a second sub-capping layer (CPL-1, 50nm thick) stacked sequentially.

[0151] (2) Fabrication method of organic light-emitting device 1:

[0152] First, a driving substrate layer is provided, a first electrode (anode) is formed on the driving substrate, and the first electrode is washed, that is, it is washed with alkali, washed with pure water, dried, and then washed with ultraviolet-ozone to remove organic residues on the surface of the anode layer. The driving substrate layer is made of transparent glass, the material of the first electrode is Ag, and the thickness is 100nm.

[0153] Next, using a vacuum evaporation apparatus, HT and PD materials are deposited on the first electrode to form a hole injection layer with a thickness of 10 nm and a mass ratio of HT to PD of 97:3. Then, HT material is deposited on the hole injection layer to form a hole transport layer with a thickness of 117 nm. Subsequently, EB material is deposited on the hole transport layer to form an electron blocking layer with a thickness of 10 nm. Next, BH and BD materials are deposited on the electron blocking layer to form a light-emitting layer, where BH is the host material and BD is the dopant material, with a doping ratio of 3% by weight, and the light-emitting layer has a thickness of 20 nm. Then, HB material is deposited on the light-emitting layer to form a hole blocking layer with a thickness of 8 nm. Next, ET and Liq materials are deposited on the hole blocking layer to form an electron transport layer with a thickness of 30 nm and a mass ratio of ET to Liq of 1:1. Finally, LiF material is deposited on the electron transport layer to form an electron injection layer with a thickness of 1 nm.

[0154] Then, Mg and Ag materials are vapor-deposited on the electron injection layer to form a second electrode (cathode) with a film thickness of 16 nm, wherein the mass ratio of Mg to Ag is 1:9;

[0155] Finally, compound M1 is deposited on the second electrode to form a first sub-capping layer with a thickness of 15 nm; then CPL-1 is deposited on the first sub-capping layer to form a second sub-capping layer with a thickness of 50 nm.

[0156] Example 2

[0157] The structure and fabrication method of the organic light-emitting device 2 are the same as those of the organic light-emitting device 1 in Example 1. The only difference is that the material of the first sub-capping layer of the organic light-emitting device 2 is compound M2. The other structures and materials of the organic light-emitting device 2 are the same as those of the organic light-emitting device 1.

[0158] Example 3

[0159] The structure and fabrication method of the organic light-emitting device 3 are the same as those of the organic light-emitting device 1 in Example 1. The only difference is that the material of the first sub-capping layer of the organic light-emitting device 3 is compound M3. The other structures and materials of the organic light-emitting device 3 are the same as those of the organic light-emitting device 1.

[0160] Example 4

[0161] The structure and fabrication method of the organic light-emitting device 4 are the same as those of the organic light-emitting device 1 in Example 1. The only difference is that the material of the first sub-capping layer of the organic light-emitting device 4 is compound M4. The other structures and materials of the organic light-emitting device 4 are the same as those of the organic light-emitting device 1.

[0162] Example 5

[0163] The structure and fabrication method of the organic light-emitting device 5 are the same as those of the organic light-emitting device 1 in Example 1. The only difference is that the material of the first sub-capping layer of the organic light-emitting device 5 is compound M5. The other structures and materials of the organic light-emitting device 5 are the same as those of the organic light-emitting device 1.

[0164] Example 6

[0165] The structure and fabrication method of the organic light-emitting device 6 are the same as those of the organic light-emitting device 1 in Example 1. The only difference is that the material of the first sub-capping layer of the organic light-emitting device 6 is compound M6. The other structures and materials of the organic light-emitting device 6 are the same as those of the organic light-emitting device 1.

[0166] Example 7

[0167] The structure and fabrication method of the organic light-emitting device 7 are the same as those of the organic light-emitting device 1 in Example 1. The only difference is that the material of the first sub-capping layer of the organic light-emitting device 7 is compound M7. The other structures and materials of the organic light-emitting device 7 are the same as those of the organic light-emitting device 1.

[0168] Example 8

[0169] The structure and fabrication method of the organic light-emitting device 8 are the same as those of the organic light-emitting device 1 in Example 1. The only difference is that the material of the first sub-capping layer of the organic light-emitting device 8 is compound M8. The other structures and materials of the organic light-emitting device 8 are the same as those of the organic light-emitting device 1.

[0170] Example 9

[0171] The structure and fabrication method of the organic light-emitting device 9 are the same as those of the organic light-emitting device 1 in Example 1. The only difference is that the material of the first sub-capping layer of the organic light-emitting device 9 is compound M9. The other structures and materials of the organic light-emitting device 9 are the same as those of the organic light-emitting device 1.

[0172] Example 10

[0173] The structure and fabrication method of the organic light-emitting device 10 are the same as those of the organic light-emitting device 1 in Example 1. The only difference is that the material of the first sub-capping layer of the organic light-emitting device 10 is compound M10. The other structures and materials of the organic light-emitting device 10 are the same as those of the organic light-emitting device 1.

[0174] Example 11

[0175] The structure and fabrication method of the organic light-emitting device 11 are the same as those of the organic light-emitting device 1 in Example 1. The only difference is that the material of the first sub-capping layer of the organic light-emitting device 11 is compound M11. The other structures and materials of the organic light-emitting device 11 are the same as those of the organic light-emitting device 1.

[0176] Example 12

[0177] The structure and fabrication method of the organic light-emitting device 12 are the same as those of the organic light-emitting device 1 in Example 1. The only difference is that the material of the first sub-capping layer of the organic light-emitting device 12 is compound M12. The other structures and materials of the organic light-emitting device 12 are the same as those of the organic light-emitting device 1.

[0178] Example 13

[0179] The structure and fabrication method of the organic light-emitting device 13 are the same as those of the organic light-emitting device 1 in Example 1. The only difference is that the material of the first sub-capping layer of the organic light-emitting device 13 is compound M13. The other structures and materials of the organic light-emitting device 13 are the same as those of the organic light-emitting device 1.

[0180] Example 14

[0181] The structure and fabrication method of the organic light-emitting device 14 are the same as those of the organic light-emitting device 1 in Example 1. The only difference is that the material of the first sub-capping layer of the organic light-emitting device 14 is compound M14. The other structures and materials of the organic light-emitting device 14 are the same as those of the organic light-emitting device 1.

[0182] Example 15

[0183] The structure and fabrication method of the organic light-emitting device 15 are the same as those of the organic light-emitting device 1 in Example 1. The only difference is that the material of the first sub-capping layer of the organic light-emitting device 15 is compound M15. The other structures and materials of the organic light-emitting device 15 are the same as those of the organic light-emitting device 1.

[0184] Example 16

[0185] The structure and fabrication method of the organic light-emitting device 16 are the same as those of the organic light-emitting device 1 in Example 1. The only difference is that the material of the first sub-capping layer of the organic light-emitting device 16 is compound M16. The other structures and materials of the organic light-emitting device 16 are the same as those of the organic light-emitting device 1.

[0186] Comparative Example 1

[0187] The structure and fabrication method of the organic light-emitting device 17 are the same as those of the organic light-emitting device 1 in Example 1. The only difference is that the organic light-emitting device 17 only includes a first sub-capping layer and does not have a second sub-capping layer. The material of the first sub-capping layer is compound M1. The other structures and materials of the organic light-emitting device 17 are the same as those of the organic light-emitting device 1.

[0188] Comparative Example 2

[0189] The structure and fabrication method of the organic light-emitting device 18 are the same as those of the organic light-emitting device 1 in Example 1. The only difference is that the organic light-emitting device 18 only includes a first sub-capping layer and does not have a second sub-capping layer. The material of the first sub-capping layer is compound M4. The other structures and materials of the organic light-emitting device 18 are the same as those of the organic light-emitting device 1.

[0190] Comparative Example 3

[0191] The structure and fabrication method of the organic light-emitting device 19 are the same as those of the organic light-emitting device 1 in Example 1. The only difference is that the organic light-emitting device 19 only includes a second sub-capping layer and does not have a first sub-capping layer. The material of the second sub-capping layer is compound CPL-1. The other structures and materials of the organic light-emitting device 19 are the same as those of the organic light-emitting device 1.

[0192] Comparative Example 4

[0193] The structure and fabrication method of the organic light-emitting device 20 are the same as those of the organic light-emitting device 1 in Example 1. The only difference is that the material of the first sub-capping layer of the organic light-emitting device 20 is compound Ref-01. The other structures and materials of the organic light-emitting device 20 are the same as those of the organic light-emitting device 1.

[0194] Description of the materials, equipment, and testing methods used in the embodiments of this application:

[0195] Material source: Some raw materials were purchased commercially or synthesized by referring to existing literature. The molecular structural formulas of the relevant materials involved in the embodiments of this application are shown below:

[0196]

[0197]

[0198] .

[0199] Test equipment: Vacuum evaporation equipment, Choshu Sangyo 200*200mm evaporation equipment from Japan.

[0200] Test Method: An IVL (current-voltage-luminance) testing system (Suzhou Fosstar Scientific Instruments Co., Ltd.) was used, with software EILV20060707 selected, to test the efficiency versus current density curves of organic light-emitting devices 1 to 20. The parameters were measured at 10 mA / cm². 2 The data under the specified conditions shall prevail (i.e., the test current density reaches 10 mA / cm²). 2 (The corresponding performance values ​​at each time). The test results of the above organic light-emitting devices are shown in Table 1:

[0201] Table 1

[0202]

[0203] Where n1 represents the refractive index of the first sub-coating layer for light with a wavelength of 460 nm, and n2 represents the refractive index of the second sub-coating layer for light with a wavelength of 460 nm.

[0204] As can be seen from the comparison of the data of Examples 1-16 and Comparative Examples 1-3 in Table 1, the luminous efficiency of the organic light-emitting devices 1-16 of this application is significantly higher than that of the organic light-emitting devices 17-19 of the comparative examples. This indicates that when only a single high-refractive-index or low-refractive-index capping layer is used, the luminous efficiency of the organic light-emitting device is poor. However, when the combination of low-refractive-index capping layer and high-refractive-index capping layer of this application is used, the luminous efficiency of the organic light-emitting device is significantly improved.

[0205] A comparison of the data from Examples 1 to 16 with Comparative Example 4 shows that the luminous efficiency of the organic light-emitting devices 1 to 16 of this application is higher than that of the organic light-emitting device 20. That is, when the material of the second sub-capping layer with a high refractive index remains unchanged, the luminous efficiency of the organic light-emitting device can be significantly improved by using the organic compound of formula (1) of this application to prepare the first sub-capping layer with a low refractive index.

[0206] In summary, the organic compound represented by formula (1) of this application can be used to prepare a capping layer with a low refractive index, and when the low refractive index capping layer is combined with a high refractive index capping layer to form the capping layer structure of an organic light-emitting device, the luminous efficiency of the organic light-emitting device can be effectively enhanced.

[0207] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying 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, "multiple" means two or more, unless otherwise explicitly specified.

[0208] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0209] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0210] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. An organic light-emitting device, characterized in that, include: First electrode; A light-emitting functional layer is disposed on the first electrode; The second electrode is disposed on the side of the light-emitting functional layer away from the first electrode; as well as A cover layer is disposed on the side of the second electrode away from the light-emitting functional layer; The capping layer includes a first sub-capping layer and a second sub-capping layer. The first sub-capping layer is located between the second electrode and the second sub-capping layer, and the refractive index of the first sub-capping layer is less than the refractive index of the second sub-capping layer. The material of the first sub-coating layer comprises at least one organic compound having a refractive index of 1.40 to 1.70 for light with a wavelength of 460 nm, and the organic compound is selected from any of the following structures: 。 2. The organic light-emitting device according to claim 1, characterized in that, The first sub-coating layer has a refractive index of less than or equal to 1.60 for light with a wavelength of 460 nm, and the second sub-coating layer has a refractive index of greater than or equal to 1.85 for light with a wavelength of 460 nm.

3. The organic light-emitting device according to claim 1, characterized in that, The difference between the refractive index of the second sub-coating layer and the refractive index of the first sub-coating layer for light with a wavelength of 460 nm is greater than or equal to 0.

3. And / or, the difference between the refractive index of the first sub-coating layer for light with a wavelength of 460 nm and the refractive index of the first sub-coating layer for light with a wavelength of 620 nm is less than or equal to 0.

3.

4. A display device, characterized in that, Including the organic light-emitting device as described in any one of claims 1 to 3.

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