Organic light emitting device and display apparatus

Abstract

The present disclosure provides an organic light-emitting device and a display device, and belongs to the technical field of display. The organic light-emitting device comprises a first electrode layer, a light-emitting functional layer, a second electrode layer and a cover layer which are sequentially stacked, wherein the cover layer comprises a first cover layer material and a second cover layer material; the first cover layer material and the second cover layer material satisfy the following conditions: n1(λ1)-n2(λ1)≥0.2, 440nm≤λ1≤480nm; n1(λ2)-n2(λ2)≥0.1, 500nm≤λ2≤550nm; n1(λ3)-n2(λ3)≥0.1, 600nm≤λ3≤640nm.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and in particular to an organic light-emitting device and display apparatus. Background Technology

[0002] Currently used organic light-emitting diode (OLED) devices mostly employ a top-emitting device structure, utilizing a reflective anode and a transparent cathode, and enhancing light extraction efficiency through the microcavity effect. A crucial functional layer in this device is the capping layer (CPL). The capping layer consists of two layers: a high-refractive-index material and a low-refractive-index material. This combination of high and low refractive indices in the capping layer achieves superior light extraction.

[0003] However, the light emission performance of existing cover materials cannot meet user needs.

[0004] The information disclosed in the background section is only for enhancing the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this disclosure is to provide an organic light-emitting device and display apparatus that improves the light extraction efficiency of the device.

[0006] To achieve the above-mentioned objectives, the present disclosure adopts the following technical solution:

[0007] According to a first aspect of this disclosure, an organic light-emitting device is provided, comprising a first electrode layer, a light-emitting functional layer, a second electrode layer, and a cover layer stacked sequentially, wherein the cover layer comprises a first cover layer material and a second cover layer material;

[0008] The first cover layer material and the second cover layer material satisfy the following:

[0009] n1(λ1)-n2(λ1)≥0.2, 440nm≤λ1≤480nm;

[0010] n1(λ2)-n2(λ2)≥0.1, 500nm≤λ2≤550nm;

[0011] n1(λ3)-n2(λ3)≥0.1, 600nm≤λ3≤640nm;

[0012] The light-emitting functional layer includes a hole transport layer, an organic light-emitting layer, and an electron transport layer sequentially stacked along a direction away from the first electrode layer, wherein the hole transport layer, the organic light-emitting layer, and the electron transport layer satisfy the following:

[0013] 0.1≤n3(λ1)-n4(λ1)≤0.8; 0.1≤n3(λ2)-n4(λ2)≤0.8;

[0014] 0.1≤n3(λ3)-n4(λ3)≤0.8;

[0015] 0.1≤n5(λ1)-n4(λ1)≤0.8; 0.1≤n5(λ2)-n4(λ2)≤0.8;

[0016] 0.1≤n5(λ3)-n4(λ3)≤0.8;

[0017] Wherein, λ1, λ2, and λ3 represent different wavelength ranges of light;

[0018] n1 represents the refractive index of the first cover layer material, and n2 represents the refractive index of the second cover layer material;

[0019] n3 represents the refractive index of the hole transport layer, n4 represents the refractive index of the organic light-emitting layer, and n5 represents the refractive index of the electron transport layer.

[0020] In one exemplary embodiment of this disclosure, the first cover layer material and the second cover layer material satisfy the following:

[0021] k1(λ4)-k2(λ5)≥0.1, λ4=405nm, λ5=430nm;

[0022] 0.8≤[k2(λ4)-k2(λ5)] / [k1(λ4)-k1(λ5)]≤1;

[0023] k1 (λ6) ≤ 0.08; k2 (λ6) ≤ 0.08, λ6 ≥ 430nm;

[0024] Wherein, λ4, λ5, and λ6 represent different wavelength ranges of light;

[0025] k1 represents the absorption coefficient of the first covering layer material, and k2 represents the absorption coefficient of the second covering layer material.

[0026] In one exemplary embodiment of this disclosure, the first covering layer material is selected from the structure shown in Formula 1.

[0027]

[0028] in," " represents a chemical bond;

[0029] Group A1 is selected from the structure shown in chemical formula 1-1;

[0030] At least one of Ar1, Ar2, Ar3, and Ar4 is selected from the structure shown in chemical formula 1-2. When Ar1, Ar2, Ar3, and Ar4 are not selected from the structure shown in chemical formula 1-2, Ar1, Ar2, Ar3, and Ar4 are each independently selected from hydrogen, deuterium, halogen, alkyl with 1-6 carbon atoms, aryl with 6-20 carbon atoms (substituted or unsubstituted), or heteroaryl with 5-23 carbon atoms (substituted or unsubstituted).

[0031] X1 is selected from O or S;

[0032] R1 is selected from hydroxyl, alkyl with 1-4 carbon atoms, and aryl with 6-12 carbon atoms;

[0033] R2 is selected from alkyl groups having 1-4 carbon atoms or aryl groups having 6-12 carbon atoms;

[0034] r1 is the number of R1s, and r1 can be selected from 0, 1, 2, 3 or 4;

[0035] r2 is the number of R2, and r2 is selected from 0, 1, 2, 3 or 4;

[0036] m1 is selected from 1, 2 or 3. When m1 > 1, two adjacent benzene rings can be connected to form a ring.

[0037] The substituents on Ar1, Ar2, Ar3, and Ar4 are each independently selected from deuterium, halogens, alkyl groups with 1-4 carbon atoms, aryl groups with 6-12 carbon atoms, and heteroaryl groups with 5-12 carbon atoms.

[0038] In one exemplary embodiment of this disclosure, the group A1 is selected from the group consisting of:

[0039] .

[0040] In one exemplary embodiment of this disclosure, Ar1, Ar2, Ar3, and Ar4 are each independently selected from hydrogen, substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted fluorenyl, and the structures shown in chemical formulas 1-2.

[0041] The substituents on Ar1, Ar2, Ar3, and Ar4 are each independently selected from deuterium, halogen, methyl, phenyl, and pyridyl.

[0042] In one exemplary embodiment of this disclosure, the second covering layer material is selected from inorganic materials or the structure shown in Formula 2.

[0043]

[0044] in," " represents a chemical bond;

[0045] A2 and A3 are each independently selected from the structures shown in chemical formula 2-1 or chemical formula 2-2;

[0046] X2 and X3 are each independently selected from B(R8) and C(R9R). 10 ), O, S;

[0047] X4 and X5 are each independently selected from CH and N;

[0048] Y is selected from C and Si;

[0049] L1 and L2 are each independently selected from arylene groups with 6-20 carbon atoms, either substituted or unsubstituted.

[0050] R3, R4, R5, R6, and R7 are each independently selected from aryl groups with 6-20 substituted or unsubstituted carbon atoms;

[0051] R8, R9, R 10 Each is independently selected from hydrogen, alkyl groups having 1-6 carbon atoms, or substituted or unsubstituted aryl groups having 6-20 carbon atoms;

[0052] L1, L2, R3, R4, R5, R6, R7, R8, R9, R 10 The substituents on each of the following are independently selected from deuterium, halogens, and alkyl groups having 1-6 carbon atoms;

[0053] The structure shown in chemical formula 2-1 or chemical formula 2-2 contains a tert-butyl group.

[0054] In one exemplary embodiment of this disclosure, L1 and L2 are each independently selected from substituted or unsubstituted phenylene oxides.

[0055] In one exemplary embodiment of this disclosure, R3, R4, R5, R6, and R7 are each independently selected from substituted or unsubstituted phenyl groups;

[0056] The substituents on R3, R4, R5, R6, and R7 are each independently selected from methyl, ethyl, and tert-butyl.

[0057] In one exemplary embodiment of this disclosure, the light-emitting functional layer further includes an electron blocking layer and a hole blocking layer, wherein the electron blocking layer is disposed between the hole transport layer and the organic light-emitting layer, and the hole blocking layer is disposed between the organic light-emitting layer and the electron transport layer;

[0058] The hole blocking layer and the electron transport layer satisfy the following:

[0059] 0.4 eV≤LUMO(HBL)-LUMO(ETL)≤1 eV;

[0060] The electron blocking layer and the hole transport layer satisfy the following:

[0061] 0.3 eV≤HOMO(HTL) - HOMO(EBL)≤1 eV;

[0062] Wherein, LUMO (HBL) is the lowest unoccupied molecular orbital LUMO energy level of the hole blocking layer material, and LUMO (ETL) is the lowest unoccupied molecular orbital LUMO energy level of the electron transport layer material;

[0063] HOMO (HTL) is the highest occupied molecular orbital HOMO level of the hole transport layer material, and HOMO (EBL) is the highest occupied molecular orbital HOMO level of the electron blocking layer material.

[0064] In one exemplary embodiment of this disclosure, the organic light-emitting layer material comprises a host material and a dopant material;

[0065] The bulk material of the organic light-emitting layer and the hole-blocking layer satisfy the following:

[0066] T1(HBL) > T1(Host);

[0067] The bulk material of the organic light-emitting layer and the electron-blocking layer satisfy the following:

[0068] T1(EBL) > T1(Host);

[0069] Wherein, T1(HBL) is the lowest triplet energy of the hole blocking layer material, T1(EBL) is the lowest triplet energy of the electron blocking layer material, and T1(Host) is the lowest triplet energy of the organic light-emitting layer host material.

[0070] In one exemplary embodiment of this disclosure, the host material of the organic light-emitting layer and the dopant material of the organic light-emitting layer satisfy the following:

[0071] T1(Dopant)>T1(Host);

[0072] S1(Host)>S1(Dopant);

[0073] Wherein, T1 (Dopant) is the lowest triplet excitation energy of the organic light-emitting layer doped material, S1 (Host) is the lowest singlet excitation energy of the organic light-emitting layer host material, and S1 (Dopant) is the lowest singlet excitation energy of the organic light-emitting layer doped material.

[0074] In one exemplary embodiment of this disclosure, the hole mobility and electron mobility of the organic light-emitting layer satisfy the following:

[0075] 0.01<μh(EML) / μe(EML)≤100;

[0076] Wherein, μh(EML) is the hole mobility of the organic light-emitting layer, and μe(EML) is the electron mobility of the organic light-emitting layer.

[0077] In one exemplary embodiment of this disclosure, the light-emitting functional layer further includes a hole injection layer, which is disposed between the first electrode layer and the hole transport layer;

[0078] The resistivity of the hole injection layer is not less than 100Ω. m.

[0079] In one exemplary embodiment of this disclosure, the cover layer includes a first cover layer and a second cover layer stacked along a direction away from the first electrode layer, the first cover layer comprising the first cover layer material, and the second cover layer comprising the second cover layer material;

[0080] The molecular orientation of the first covering layer is between -0.5 and -0.2.

[0081] In one exemplary embodiment of this disclosure, the inorganic material is selected from one or more of metal compounds, non-metal compounds, metals, and metal alloys.

[0082] According to a second aspect of this disclosure, a display device is provided, including an organic light-emitting device as described in the first aspect.

[0083] The organic light-emitting device disclosed herein uses a first capping layer material with a high refractive index and a second capping layer material with a low refractive index. The refractive indices of the first and second capping layer materials satisfy different difference relationships in different wavelength ranges. This difference relationship helps to improve the optical coupling efficiency of the organic light-emitting device, improve the light emission mode, and achieve higher light extraction efficiency. Furthermore, by adjusting the refractive index relationship of the hole transport layer, the organic light-emitting layer, and the electron transport layer, the light extraction efficiency of the device is further improved. Attached Figure Description

[0084] The above and other features and advantages of this disclosure will become more apparent from a detailed description of exemplary embodiments thereof with reference to the accompanying drawings.

[0085] Figure 1 This is a schematic diagram of the structure of an organic electroluminescent device in an exemplary embodiment of this disclosure;

[0086] Figure 2This is a schematic diagram of the structure of an organic electroluminescent device in another exemplary embodiment of this disclosure.

[0087] The annotations for the main components in the diagram are explained below:

[0088] 100 - First electrode layer; 200 - Second electrode layer; 300 - Light-emitting functional layer; 310 - Hole injection layer; 321 - Hole transport layer; 322 - Electron blocking layer; 330 - Organic light-emitting layer; 340 - Hole blocking layer; 350 - Electron transport layer; 360 - Electron injection layer; 400 - Cover layer. Detailed Implementation

[0089] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that this disclosure will be more comprehensive and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are set forth to give a full understanding of embodiments of this disclosure.

[0090] For clarity, the thickness of regions and layers may be exaggerated in the figures. The same reference numerals in the figures denote the same or similar structures, and therefore their detailed descriptions will be omitted.

[0091] The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a full understanding of embodiments of this disclosure. However, those skilled in the art will recognize that the technical solutions of this disclosure can be practiced without one or more of the specific details described, or other methods, components, materials, etc., can be employed. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring the main technical concept of this disclosure.

[0092] When a structure is "on" other structures, it may mean that the structure is integrally formed on other structures, or that the structure is "directly" set on other structures, or that the structure is "indirectly" set on other structures through another structure.

[0093] The terms “a,” “one,” and “the” are used to indicate the existence of one or more elements / components / etc.; the terms “including” and “having” are used to indicate an open-ended inclusion and that other elements / components / etc. may exist in addition to those listed. The terms “first” and “second” are used only as markers and are not a limitation on the number of objects.

[0094] Organic light-emitting devices (OLEDs) are active-matrix light-emitting devices with advantages such as light emission, ultra-thinness, wide viewing angle, high brightness, high contrast, low power consumption, and extremely fast response speed. They have gradually become a promising next-generation display technology. An OLED includes an anode, a cathode, and an organic light-emitting layer disposed between the anode and cathode. Its light-emitting principle involves injecting holes and electrons from the anode and cathode, respectively, into the organic light-emitting layer. When electrons and holes meet in the organic light-emitting layer, they recombine to generate excitons. These excitons emit light as they transition from the excited state to the ground state.

[0095] Based on the direction of light emission, OLED devices can be divided into bottom-emitting OLED devices and top-emitting OLED devices. In bottom-emitting devices, light is emitted from the substrate, with the reflective electrode above the organic light-emitting layer and the transparent electrode below it. The thin-film transistor portion of a bottom-emitting OLED device cannot transmit light, resulting in a smaller light-emitting area. In top-emitting devices, the transparent electrode is above the organic light-emitting layer, and the reflective electrode is below it, so light is emitted from the opposite direction of the substrate, thus increasing the light-transmitting area. Therefore, current OLED devices are predominantly top-emitting.

[0096] Top-emitting OLED (OLED) devices utilize a reflective anode and a transparent cathode, employing a microcavity effect to enhance light extraction efficiency. In this device, a capping layer is placed above the cathode, creating a combination of high and low refractive indices for improved light extraction. However, in related technologies, the capping layer has a low refractive index in the visible light range, resulting in low light extraction efficiency and limited effectiveness in improving the OLED device's luminous efficiency. Consequently, the OLED device's luminous performance fails to meet user needs. Furthermore, the capping layer absorbs relatively little ultraviolet light from the external environment, making it difficult to prevent damage to internal components from ultraviolet radiation, leading to a shorter OLED device lifespan and impacting the user experience.

[0097] like Figure 1 As shown, this embodiment of the present disclosure provides an organic light-emitting device, including a first electrode layer 100, a light-emitting functional layer 300, a second electrode layer 200, and a capping layer 400 sequentially stacked. The capping layer 400 includes a first capping layer material and a second capping layer material. The first capping layer material and the second capping layer material satisfy the following conditions:

[0098] n1(λ1)-n2(λ1)≥0.2, 440nm≤λ1≤480nm;

[0099] n1(λ2)-n2(λ2)≥0.1, 500nm≤λ2≤550nm;

[0100] n1(λ3)-n2(λ3)≥0.1, 600nm≤λ3≤640nm;

[0101] The light-emitting functional layer 300 includes a hole transport layer 321, an organic light-emitting layer 330, and an electron transport layer 350 sequentially stacked along a direction away from the first electrode layer 100. The hole transport layer 321, the organic light-emitting layer 330, and the electron transport layer 350 satisfy the following conditions:

[0102] 0.1≤n3(λ1)-n4(λ1)≤0.8; 0.1≤n3(λ2)-n4(λ2)≤0.8;

[0103] 0.1≤n3(λ3)-n4(λ3)≤0.8;

[0104] 0.1≤n5(λ1)-n4(λ1)≤0.8; 0.1≤n5(λ2)-n4(λ2)≤0.8;

[0105] 0.1≤n5(λ3)-n4(λ3)≤0.8;

[0106] Wherein, λ1, λ2, and λ3 represent different wavelength ranges of light;

[0107] n1 represents the refractive index of the first cover layer material, and n2 represents the refractive index of the second cover layer material;

[0108] n3 represents the refractive index of the hole transport layer 321, n4 represents the refractive index of the organic light-emitting layer 330, and n5 represents the refractive index of the electron transport layer 350.

[0109] The organic light-emitting device disclosed herein uses a first capping layer material with a high refractive index and a second capping layer material with a low refractive index. The refractive indices of the first and second capping layer materials satisfy different difference relationships in different wavelength ranges. This difference relationship helps to improve the optical coupling efficiency of the organic light-emitting device, improve the light emission mode, and achieve higher light extraction efficiency. Furthermore, by adjusting the refractive index relationship of the hole transport layer 321, the organic light-emitting layer 330, and the electron transport layer 350, the light extraction efficiency of the device is further improved.

[0110] The components of the organic light-emitting device provided in this disclosure embodiment will be described in detail below with reference to the accompanying drawings:

[0111] The organic light-emitting device disclosed herein includes a first electrode layer 100, a light-emitting functional layer 300, a second electrode layer 200, and a capping layer 400 stacked sequentially.

[0112] The first electrode layer 100 can serve as the anode of the light-emitting device. Optionally, the anode includes anode materials, preferably those with a high work function that facilitates hole injection into the functional layer. Specific examples of anode materials include: metals such as nickel, platinum, vanadium, chromium, copper, zinc, and gold, or alloys thereof; metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); combinations of metals and oxides such as ZnO:Al or SnO2:Sb; or conductive polymers such as poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxy)thiophene] (PEDT), polypyrrole, and polyaniline, but are not limited thereto. Preferably, a transparent electrode comprising indium tin oxide (ITO) as the anode is included.

[0113] The second electrode layer 200 can serve as the cathode of the light-emitting device. The cathode is preferably made of a material with a low work function to facilitate electron injection into the organic light-emitting layer 330, while also possessing good light transmittance and conductivity. Specific examples of cathode materials that can be used in this disclosure include: metals, metal oxides, and metal alloys, such as aluminum (Al), silver (Ag), gold (Au), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium (Li), potassium (K), sodium (Na), tin (Sn), titanium (Ti), lead (Pb), samarium (Sm), yttrium (Y), indium tin oxide (ITO), magnesium-silver alloy (Mg:Ag), and ytterbium-gold alloy (Yb:Au). Ytterbium silver alloy (Yb:Ag), lithium aluminum alloy (Li:Al), lithium calcium magnesium alloy (Li:Ca:Al), etc.; and laminated materials, such as magnesium / aluminum (Mg / Al), magnesium / silver (Mg / Ag), aluminum / silver (Al / Ag), aluminum / gold (Al / Au), ytterbium / gold (Yb / Au), ytterbium / silver (Yb / Ag), calcium / magnesium (Ca / Mg), calcium / silver (Ca / Ag), barium / silver (Ba / Ag), etc., but not limited to these.

[0114] The light-emitting functional layer 300 may include a hole transport layer 321, an organic light-emitting layer 330, and an electron transport layer 350, which are sequentially stacked along a direction away from the first electrode layer 100. Holes are injected into the organic light-emitting layer 330 by the anode and the hole transport layer 321, and electrons are injected into the organic light-emitting layer 330 by the cathode and the electron transport layer 350. When electrons and holes meet in the organic light-emitting layer 330, they recombine to generate excitons. These excitons emit light as they transition from the excited state to the ground state.

[0115] A capping layer 400 is disposed on the side of the second electrode layer 200 away from the first electrode layer 100. The capping layer 400 comprises a first capping layer material and a second capping layer material. It should be noted that the capping layer 400 can be formed by mixing the first and second capping layer materials and then performing a film-forming process. Alternatively, the first capping layer can be formed from the first capping layer material, and the second capping layer can be formed from the second capping layer material, with the second capping layer disposed on the side of the first capping layer away from the first electrode layer 100. Both the second and second capping layer materials can improve the luminous efficiency of the device.

[0116] In this disclosure, the first cover layer material and the second cover layer material satisfy the following:

[0117] n1(λ1)-n2(λ1)≥0.2, 440nm≤λ1≤480nm;

[0118] n1(λ2)-n2(λ2)≥0.1, 500nm≤λ2≤550nm;

[0119] n1(λ3)-n2(λ3)≥0.1, 600nm≤λ3≤640nm;

[0120] Wherein, λ1, λ2, and λ3 represent different wavelength ranges of light;

[0121] n1 represents the refractive index of the second coating material, and n2 represents the refractive index of the second coating material.

[0122] Among them, light in the wavelength range of 440nm-480nm is blue light, light in the wavelength range of 500nm-550nm is green light, and light in the wavelength range of 600nm-640nm is red light. When the refractive indices of the second capping layer material and the second capping layer material satisfy the above relationship, the cooperation between the second capping layer material and the second capping layer material helps to improve the optical coupling efficiency of the device, improve the light emission mode, and enable the light that was originally confined inside the device to be emitted out of the device, thus exhibiting higher light extraction efficiency.

[0123] Specifically, n1(λ1)-n2(λ1)≥0.2, 0.25, 0.3, 0.32, 0.35, 0.4, 0.45, 0.5, 0.6 or 0.7, but not limited to these;

[0124] n1(λ2)-n2(λ2)≥0.1, 0.2, 0.25, 0.3, 0.32, 0.35, 0.4, 0.45, 0.5, 0.6 or 0.7, but not limited to these;

[0125] n1(λ3)-n2(λ3)≥0.1, 0.2, 0.25, 0.3, 0.32, 0.35, 0.4, 0.45, 0.5, 0.6 or 0.7, but not limited to these.

[0126] Specifically, n1(λ1=460)-n2(λ1=460)≥0.2;

[0127] n1(λ2=530)-n2(λ2=530)≥0.1;

[0128] n1(λ3=620)-n2(λ3=620)≥0.1.

[0129] Furthermore, this disclosure further improves the light extraction efficiency of the device by adjusting the relationship between the refractive indices of the hole transport layer 321, the organic light-emitting layer 330, and the electron transport layer 350.

[0130] The hole transport layer 321, the organic light-emitting layer 330, and the electron transport layer 350 satisfy the following:

[0131] 0.1≤n3(λ1)-n4(λ1)≤0.8; 0.1≤n3(λ2)-n4(λ2)≤0.8;

[0132] 0.1≤n3(λ3)-n4(λ3)≤0.8;

[0133] 0.1≤n5(λ1)-n4(λ1)≤0.8; 0.1≤n5(λ2)-n4(λ2)≤0.8;

[0134] 0.1≤n5(λ3)-n4(λ3)≤0.8;

[0135] Wherein, n3 represents the refractive index of the hole transport layer 321, n4 represents the refractive index of the organic light-emitting layer 330, and n5 represents the refractive index of the electron transport layer 350.

[0136] Specifically, 0.1≤n3(λ1=460)-n4(λ1=460)≤0.8; 0.1≤n3(λ2=530)-n4(λ2=530)≤0.8;

[0137] 0.1≤n3(λ3=620)-n4(λ3=620)≤0.8;

[0138] 0.1≤n5(λ1=460)-n4(λ1=460)≤0.8; 0.1≤n5(λ2=530)-n4(λ2=530)≤0.8;

[0139] 0.1≤n5(λ3=620)-n4(λ3=620)≤0.8.

[0140] It should be noted that, in this disclosure, the numerical range of 0.1 to 0.8 may include 0.1, 0.2, 0.25, 0.3, 0.32, 0.35, 0.4, 0.45, 0.5, 0.6, 0.65, 0.7, 0.75 or 0.8, but is not limited thereto.

[0141] In some embodiments of this disclosure, the second cover layer material and the second cover layer material further satisfy the following:

[0142] k1(λ4)-k2(λ5)≥0.1, λ4=405nm, λ5=430nm;

[0143] 0.8≤[k2(λ4)-k2(λ5)] / [k1(λ4)-k1(λ5)]≤1;

[0144] k1 (λ6) ≤ 0.08; k2 (λ6) ≤ 0.08, λ6 ≥ 430nm;

[0145] Wherein, λ4, λ5, and λ6 represent different wavelength ranges of light;

[0146] k1 represents the absorption coefficient of the first covering layer material, and k2 represents the absorption coefficient of the second covering layer material.

[0147] It should be noted that the numerical range of 0.8 to 1 in this disclosure may include 0.8, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99 or 1.

[0148] Light with wavelengths less than 430nm is ultraviolet light. When k1(λ4)-k2(λ5)≥0.1, the second capping layer material can have good absorption in the wavelength range of 430nm or shorter, so as to maximize the absorption of harmful light in this range and protect the eyes. Furthermore, 0.8≤[k2(λ4)-k2(λ5)] / [k1(λ4)-k1(λ5)]≤1; to ensure that light less than 430nm is well absorbed at 400 of the capping layer, so as to further maximize the absorption of harmful light in this range.

[0149] In addition, light with wavelengths greater than 430nm is visible light and can be used for displays. When k1(λ6)≤0.08 and k2(λ6)≤0.08, visible light absorption can be prevented to ensure the light extraction efficiency of the device.

[0150] In some embodiments of this disclosure, the first covering layer material is selected from the structure shown in Formula 1.

[0151]

[0152] in," " represents a chemical bond;

[0153] Group A1 is selected from the structure shown in chemical formula 1-1;

[0154] At least one of Ar1, Ar2, Ar3, and Ar4 is selected from the structure shown in chemical formula 1-2. When Ar1, Ar2, Ar3, and Ar4 are not selected from the structure shown in chemical formula 1-2, Ar1, Ar2, Ar3, and Ar4 are each independently selected from hydrogen, deuterium, halogen, alkyl with 1-6 carbon atoms, aryl with 6-20 carbon atoms (substituted or unsubstituted), or heteroaryl with 5-23 carbon atoms (substituted or unsubstituted).

[0155] X1 is selected from O or S;

[0156] R1 is selected from hydroxyl, alkyl with 1-4 carbon atoms, and aryl with 6-12 carbon atoms;

[0157] R2 is selected from alkyl groups having 1-4 carbon atoms or aryl groups having 6-12 carbon atoms;

[0158] r1 is the number of R1s, and r1 can be selected from 0, 1, 2, 3 or 4;

[0159] r2 is the number of R2, and r2 is selected from 0, 1, 2, 3 or 4;

[0160] m1 is selected from 1, 2 or 3. When m1 > 1, two adjacent benzene rings can be connected to form a ring.

[0161] The substituents on Ar1, Ar2, Ar3, and Ar4 are each independently selected from deuterium, halogens, alkyl groups with 1-4 carbon atoms, aryl groups with 6-12 carbon atoms, and heteroaryl groups with 5-12 carbon atoms.

[0162] The second capping layer material is selected from inorganic materials or the structure shown in Chemical Formula 2.

[0163]

[0164] in," " represents a chemical bond;

[0165] A2 and A3 are each independently selected from the structures shown in chemical formula 2-1 or chemical formula 2-2;

[0166] X2 and X3 are each independently selected from B(R8) and C(R9R).10 ), O, S;

[0167] X4 and X5 are each independently selected from CH and N;

[0168] Y is selected from C and Si;

[0169] L1 and L2 are each independently selected from arylene groups with 6-20 carbon atoms, either substituted or unsubstituted.

[0170] R3, R4, R5, R6, and R7 are each independently selected from aryl groups with 6-20 substituted or unsubstituted carbon atoms;

[0171] R8, R9, R 10 Each is independently selected from hydrogen, alkyl groups having 1-6 carbon atoms, or substituted or unsubstituted aryl groups having 6-20 carbon atoms;

[0172] L1, L2, R3, R4, R5, R6, R7, R8, R9, R 10 The substituents on each of the following are independently selected from deuterium, halogens, and alkyl groups having 1-6 carbon atoms;

[0173] The structure shown in chemical formula 2-1 or chemical formula 2-2 contains a tert-butyl group.

[0174] In this disclosure, the descriptive phrases “each…independently is” and “…independently selected from” are interchangeable and should be interpreted broadly. They can mean that the specific options expressed by the same symbols in different groups do not affect each other, or that the specific options expressed by the same symbols in the same group do not affect each other.

[0175] In this disclosure, a non-positioned linker bond refers to a single bond extending from a ring system. The term "" indicates that one end of the linker bond can connect to any position in the ring system that the bond penetrates, while the other end connects to the rest of the compound molecule.

[0176] For example, as shown in formula (g) below, the benzoxazole group represented by formula (g) is connected to other positions of the molecule by a non-positional linker bond that runs through the benzene ring and the oxazole ring. This means that any possible connection mode shown in formulas (g-1) to (g-5) is included.

[0177]

[0178] In this disclosure, a non-orienting substituent refers to a substituent connected by a single bond extending from the center of the ring system, indicating that the substituent can be attached to any possible position in the ring system. For example, as shown in equation (h) below, the substituent R1 represented by equation (h) is connected to the benzene ring by a non-orienting linking bond, which means that it includes any possible connection mode shown in equations (h-1) to (h-4).

[0179] .

[0180] In this disclosure, Ar1, Ar2, Ar3, Ar4, L1, L2, Ar1, R1 to R 10 The carbon number refers to the total number of carbon atoms. For example, if L1 is selected from a substituted arylene with 12 carbon atoms, then the arylene and its substituents have a total of 12 carbon atoms. For example: Ar1 is... Therefore, its carbon number is 7; L is It has 12 carbon atoms.

[0181] In this disclosure, unless otherwise specifically defined, "hetero" means a functional group comprising at least one heteroatom such as N, O, or S, with the remaining atoms being carbon and hydrogen. An unsubstituted alkyl group may be a "saturated alkyl group" without any double or triple bonds.

[0182] In this disclosure, "alkyl" can include straight-chain alkyl or branched alkyl. An alkyl group can have 1 to 10 carbon atoms, and in this disclosure, numerical ranges such as "1 to 10" refer to integers within a given range; for example, "1 to 10 carbon atoms" means an alkyl group that may contain 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms. An alkyl group can also be a lower alkyl group having 1 to 6 carbon atoms. Furthermore, an alkyl group can be substituted or unsubstituted.

[0183] Optionally, the alkyl group is selected from alkyl groups having 1 to 6 carbon atoms, including but not limited to methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, and hexyl.

[0184] In this disclosure, "alkenyl" refers to a hydrocarbon group containing one or more double bonds in a straight-chain or branched hydrocarbon chain. The alkenyl group can be unsubstituted or substituted. The alkenyl group can have 2 to 10 carbon atoms, such as 2, 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms. For example, the alkenyl group can be vinyl, butadiene, or propenyl, etc.

[0185] In this disclosure, cycloalkyl refers to a group derived from a saturated cyclic carbon chain structure. A cycloalkyl group may have 3 to 10 carbon atoms, and in this disclosure, numerical ranges such as "3 to 10" refer to integers within a given range; for example, "3 to 10 carbon atoms" means a cycloalkyl group that may contain 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms. The cycloalkyl group may be substituted or unsubstituted.

[0186] Optionally, specific embodiments of cycloalkyl groups include, but are not limited to, cyclopentyl, cyclohexyl, etc.

[0187] In this disclosure, aryl refers to any optional functional group or substituent derived from an aromatic carbon ring. An aryl group can be a monocyclic aryl (e.g., phenyl) or a polycyclic aryl; in other words, an aryl group can be a monocyclic aryl, a fused-ring aryl, two or more monocyclic aryl groups conjugated by carbon-carbon bonds, a monocyclic aryl and a fused-ring aryl group conjugated by carbon-carbon bonds, or two or more fused-ring aryl groups conjugated by carbon-carbon bonds. That is, unless otherwise stated, two or more aromatic groups conjugated by carbon-carbon bonds can also be considered as aryl groups in this disclosure. Fused-ring aryl groups may include, for example, bicyclic fused aryl (e.g., naphthyl), tricyclic fused aryl (e.g., phenanthrene, fluorene, anthracene), etc. The aryl group does not contain heteroatoms such as B, N, O, S, P, Se, and Si. For example, in this disclosure, biphenyl, terphenyl, etc., are aryl groups. Examples of aryl groups include, but are not limited to, phenyl, naphthyl, fluorenyl, anthraceneyl, phenanthryl, biphenyl, terphenyl, tetraphenyl, pentaphenyl, benzo[9,10]phenanthryl, pyrene, benzofluoranthracene, phenyl, etc. The "aryl" group of this disclosure may contain 6-30 carbon atoms. In some embodiments, the number of carbon atoms in the aryl group may be 6-25; in other embodiments, the number of carbon atoms in the aryl group may be 6-18; and in still other embodiments, the number of carbon atoms in the aryl group may be 6-13. For example, in this disclosure, the number of carbon atoms in the aryl group may be 6, 10, 12, 13, 14, 15, 18, 20, 24, 25, or 30. Of course, the number of carbon atoms may also be other numbers, which will not be listed here. In this disclosure, biphenyl can be understood as a phenyl-substituted aryl group or an unsubstituted aryl group.

[0188] In this disclosure, the term "arylene" refers to a divalent group formed by the further loss of a hydrogen atom from an aryl group.

[0189] In this disclosure, the substituted aryl group can be one or more hydrogen atoms of the aryl group that are replaced by groups such as deuterium atoms, halogen groups, cyano groups, aryl groups, heteroaryl groups, alkyl groups, cycloalkyl groups, etc. Specific examples of heteroaryl-substituted aryl groups include, but are not limited to, dibenzofuranyl-substituted phenyl groups, dibenzothiophene-substituted phenyl groups, pyridine-substituted phenyl groups, etc. It should be understood that the number of carbon atoms in the substituted aryl group refers to the total number of carbon atoms of the aryl group and its substituents. For example, a substituted aryl group with 18 carbon atoms means that the total number of carbon atoms of the aryl group and its substituents is 18.

[0190] In this disclosure, aryl groups, as substituents, include, but are not limited to, phenyl, naphthyl, biphenyl, etc.

[0191] In this disclosure, a heteroaryl group refers to a monovalent aromatic ring or a derivative thereof containing at least one heteroatom, where the heteroatom can be at least one of O, N, and S. A heteroaryl group can be a monocyclic or polycyclic heteroaryl group; in other words, a heteroaryl group can be a single aromatic ring system or a system of multiple aromatic rings conjugated by carbon-carbon bonds, and any aromatic ring system can be a single aromatic monocyclic ring or a fused aromatic ring. For example, heteroaryl groups can include thiophene, furanyl, pyrrole, imidazolyl, thiazolyl, oxazolyl, oxadiazolyl, triazolyl, pyridyl, bipyridyl, pyrimidinyl, triazinyl, acridinel, pyridazinyl, pyrazinyl, quinolinyl, quinazolinyl, quinoxazinyl, phenoxazinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, isoquinolinyl, indolyl, carbazole, benzoxazolyl, benzimidazolyl, benzyl The group includes, but is not limited to, benzothiazolyl, benzotriazolyl, benzocarbazolel, benzothiophenel, dibenzothiophenel, thienobenzothiophenel, benzofuranyl, phenanthrolinel, isoxazolyl, thiadiazolyl, benzothiazolyl, phenothiazinyl, silylfluorenyl, dibenzofuranyl, and N-arylcarbazolel (such as N-phenylcarbazolel), N-heteroarylcarbazolel (such as N-pyridylcarbazolel), and N-alkylcarbazolel (such as N-methylcarbazolel). Among these, thiophenel, furanyl, and phenanthrolinel are heteroaryl groups of the single aromatic ring type, while N-arylcarbazolel and N-heteroarylcarbazolel are heteroaryl groups of the polycyclic system type linked by carbon-carbon conjugation. The "heteroaryl" of this disclosure may contain 5-30 carbon atoms. In some embodiments, the number of carbon atoms in the heteroaryl group may be 5-23, and in other embodiments, the number of carbon atoms in the aryl group may be 5-19. For example, the number of carbon atoms may be 5, 6, 7, 10, 11, 12, 13, 18, 19, 20, 21, 22, 23, 25, or 30. Of course, the number of carbon atoms may also be other numbers, which will not be listed here.

[0192] In this disclosure, the term "hybrid aryl" refers to a divalent group formed by the further loss of a hydrogen atom from a heteroaryl group.

[0193] In this disclosure, the substituted heteroaryl group can be one or more hydrogen atoms of the heteroaryl group that are replaced by groups such as deuterium atoms, halogen groups, cyano groups, aryl groups, heteroaryl groups, alkyl groups, cycloalkyl groups, etc. Specific examples of aryl-substituted heteroaryl groups include, but are not limited to, phenyl-substituted dibenzofuranyl, phenyl-substituted dibenzothiophenyl, N-phenylcarbazoyl, etc. It should be understood that the number of carbon atoms in the substituted heteroaryl group refers to the total number of carbon atoms of the heteroaryl group and the substituents on the heteroaryl group.

[0194] In this disclosure, the heteroaryl group used as a substituent includes, but is not limited to, pyridyl, benzimidazolyl, benzothiazolyl, benzoxazolyl, benzopyridyl, benzotriazolyl, etc.

[0195] In this disclosure, halogens may include fluorine, iodine, bromine, chlorine, etc.

[0196] According to the formula ,in, Let λ be the molecular refractive index and λ be the wavelength of the incident light. The polarizability of the molecule. In this disclosure, the molecular structure of the first capping layer material contains the structure shown in chemical formula 1-2, which contains heteroatoms such as O or S, which can greatly increase the polarizability of the material molecules, thereby helping to improve the refractive index of the material molecules. In addition, the molecular structure of the first capping layer material contains the structure shown in chemical formula 1-1, which contains benzene rings. When multiple benzene rings are connected, the region is neatly arranged, and the number of material molecules contained in the same volume will increase. Accordingly, the volume occupied by a single material molecule decreases, and the refractive index of the corresponding material molecule increases.

[0197] Similarly, according to the formula In this disclosure, the second capping layer material contains sterically hindered groups as shown in Chemical Formula 2-1 or Chemical Formula 2-2. Introducing these groups into the material molecule can significantly increase the volume of the molecule, thus helping to reduce the refractive index. Simultaneously, the phosphoroxy groups, saturated carbonyl groups, and siliconyl groups contained in Chemical Formula 2-1 or Chemical Formula 2-2 have low intrinsic refractive indices, and also contain tert-butyl groups. The tert-butyl groups can significantly increase the distance between material molecules, reducing the number of material molecules contained in the same volume. Consequently, the volume occupied by a single material molecule increases, further reducing the refractive index. Secondly, the phosphoroxy groups, saturated carbonyl groups, and siliconyl groups all have good stereochemistry, and their large volume can improve the thermal stability of the material molecule, resulting in a material molecule with a low refractive index and satisfactory thermal stability. Furthermore, the second capping layer material contains S, O, and B atoms, which significantly reduce the refractive index of the molecule by breaking conjugation.

[0198] In this disclosure, "when m1 > 1, two adjacent benzene rings can connect to form a ring" means that when chemical formula 1-1 contains two or more benzene rings, the substituents on two adjacent benzene rings can connect to each other to form a ring. For example, forming... Structures such as...

[0199] In some embodiments of this disclosure, the group A1 is selected from the group consisting of:

[0200] .

[0201] In some embodiments of this disclosure, Ar1, Ar2, Ar3, and Ar4 are each independently selected from hydrogen, substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted fluorenyl, and the structures shown in Formulas 1-2.

[0202] The substituents on Ar1, Ar2, Ar3, and Ar4 are each independently selected from deuterium, halogen, methyl, phenyl, and pyridyl.

[0203] Specifically, the material of the first covering layer is selected from the group consisting of the following structures:

[0204]

[0205]

[0206] In some embodiments of this disclosure, L1 and L2 are each independently selected from substituted or unsubstituted phenylene; R3, R4, R5, R6, and R7 are each independently selected from substituted or unsubstituted phenylene; and the substituents on R3, R4, R5, R6, and R7 are each independently selected from methyl, ethyl, and tert-butyl.

[0207] Specifically, the material of the second covering layer is selected from inorganic materials or the group consisting of the following structures:

[0208]

[0209]

[0210] When the second capping layer material is an inorganic material, the inorganic material can be a metal compound, a non-metal compound, a metal, or a metal alloy. The metal compound includes metal oxides, metal nitrides, metal oxynitrides, metal carbides, and metal salts. The non-metal compound includes non-metal oxides, non-metal nitrides, and non-metal oxynitrides. The metal includes alkali metals, alkaline earth metals, transition metals, lanthanides, actinides, and main group metals.

[0211] Specifically, the material of the second covering layer may be selected from, but is not limited to, the following materials.

[0212] Examples of the metal compounds include, but are not limited to, the following materials: lithium fluoride (LiF), zinc oxide (ZnO), tin dioxide (SnO2), magnesium oxide (MgO), vanadium pentoxide (V2O5), aluminum oxide (Al2O3), cadmium oxide (CdO), cobalt oxide (CoO), aluminum oxynitride (AlON), lithium boron oxide (LiBO2), barium oxide (BaO), beryllium oxide (BeO), strontium oxide (SrO), and others. Indium tin (ITO), calcium oxide (CaO), lithium fluoride (LiF), potassium bromide (KBr), magnesium fluoride (MgF2), aluminum fluoride (AlF3), calcium fluoride (CaF2), cesium fluoride (CsF), sodium fluoride (NaF), potassium fluoride (KF), rubidium fluoride (RbF), strontium fluoride (SrF), ytterbium fluoride (YbF), yttrium fluoride (YF3), barium (BaF2), sodium iodide (NaI), potassium iodide (KI), rubidium iodide (RbI), Cesium iodide (CsI), Praseodymium fluoride (PrF3), Gadolinium fluoride (GdF3), Lanthanum fluoride (LaF3), Neodymium fluoride (NdF3), Barium fluoride (BaF2), Lithium chloride (LiCl), Lithium bromide (LiBr), Lithium iodide (LiI), Sodium bromide (NaBr), Rubidium bromide (RbBr), Cesium bromide (CsBr), Calcium chloride (CaCl2), Zinc chloride (ZnCl), Zinc bromide (ZnBr), Chloride Tin oxide (SnCl2), silver chloride (AgCl), barium chloride (BaCl2), magnesium chloride (MgCl2), magnesium bromide (MgBr2), magnesium iodide (MgI2), silver bromide (AgBr), silver iodide (AgI), chromium fluoride (CrF3), molybdenum dibromide (MoBr2), bismuth trifluoride (BiF3), lead fluoride (PbF2), lead bromide (PbBr2), strontium fluoride (SrF2), cadmium fluoride (CdF2), etc.

[0213] In some embodiments of this disclosure, the light-emitting functional layer 300 further includes an electron blocking layer 322 and a hole blocking layer 340. The electron blocking layer 322 is disposed between the hole transport layer 321 and the organic light-emitting layer 330, and the hole blocking layer 340 is disposed between the organic light-emitting layer 330 and the electron transport layer 350.

[0214] The hole blocking layer 340 and the electron transport layer 350 satisfy the following:

[0215] 0.4 eV ≤ LUMO(HBL) - LUMO(ETL) ≤ 1 eV. Wherein, LUMO(HBL) is the lowest unoccupied molecular orbital (LUMO) energy level of the hole-blocking layer 340 material, and LUMO(ETL) is the lowest unoccupied molecular orbital (LUMO) energy level of the electron transport layer 350 material. Within this range, the energy level barrier between the hole-blocking layer 340 and the electron transport layer 350 can be increased, thus slowing down the electron transport rate.

[0216] The electron blocking layer 322 and the hole transport layer 321 satisfy the following:

[0217] 0.3 eV ≤ HOMO(HTL) - HOMO(EBL) ≤ 1 eV. HOMO(HTL) is the highest occupied molecular orbital HOMO energy level of the hole transport layer 321 material, and HOMO(EBL) is the highest occupied molecular orbital HOMO energy level of the electron blocking layer 322 material.

[0218] Within this range, the slow hole transport caused by the energy level barrier can be eliminated.

[0219] In some embodiments of this disclosure, the organic light-emitting layer 330 material comprises a host material and a dopant material;

[0220] The main material of the organic light-emitting layer 330 and the hole-blocking layer 340 satisfy the following:

[0221] T1(HBL) > T1(Host);

[0222] The main material of the organic light-emitting layer 330 and the electron blocking layer 322 satisfy the following:

[0223] T1(EBL) > T1(Host);

[0224] Wherein, T1(HBL) is the lowest triplet energy of the hole blocking layer 340 material, T1(EBL) is the lowest triplet energy of the electron blocking layer 322 material, and T1(Host) is the lowest triplet energy of the host material of the organic light-emitting layer 330. Within this range, excitons are confined in the organic light-emitting layer 330 to ensure luminous efficiency.

[0225] In some embodiments of this disclosure, the host material of the organic light-emitting layer 330 and the dopant material of the organic light-emitting layer 330 satisfy the following:

[0226] T1(Dopant) > T1(Host). Here, T1(Dopant) is the lowest triplet excitation energy of the 330-doped organic light-emitting layer. Within this range, singlet excitons can be effectively generated on the host material through triplet-triplet annihilation (TTA).

[0227] S1(Host) > S1(Dopant). S1(Host) is the lowest singlet state excitation energy of the host material of the organic light-emitting layer 330, and S1(Dopant) is the lowest singlet state excitation energy of the doped material of the organic light-emitting layer 330. Within this range, the host material of the organic light-emitting layer 330 transfers excitons to the doped material to generate fluorescence.

[0228] In some embodiments of this disclosure, the hole mobility and electron mobility of the organic light-emitting layer 330 satisfy the following:

[0229] 0.01 < μh(EML) / μe(EML) ≤ 100. Where μh(EML) is the hole mobility of the organic light-emitting layer 330, and μe(EML) is the electron mobility of the organic light-emitting layer 330. Within this range, the composite region of the organic light-emitting layer 330 does not show a significant shift to the interface difference between the electron blocking layer 322 / organic light-emitting layer 330 or the electron blocking layer 322 / organic light-emitting layer 330.

[0230] In some embodiments of this disclosure, the light-emitting functional layer 300 further includes a hole injection layer 310, which is disposed between the first electrode layer 100 and the hole transport layer 321.

[0231] The resistivity of the hole injection layer 310 is not less than 100Ω. m. To avoid lateral current in the hole transport layer 321 of adjacent organic light-emitting devices sharing the hole transport layer 321, and to avoid color crosstalk between light-emitting devices when used in a display panel.

[0232] Specifically, the hole injection layer 310 can be an inorganic oxide, such as molybdenum oxide, titanium oxide, vanadium oxide, rhenium oxide, ruthenium oxide, chromium oxide, zirconium oxide, hafnium oxide, tantalum oxide, silver oxide, tungsten oxide, or manganese oxide. It can also be a dopant of a strong electron-withdrawing system, such as F4TCNQ (2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone) or HATCN (2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene). P-type doping can also be performed on the hole transport material, with the hole injection layer 310 having a thickness of 5–20 nm, formed by co-evaporation.

[0233] Hole transport layer 321 has good hole transport characteristics and can be an aromatic amine or carbazole material, such as NPB (N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine), TPD (N,N'-diphenyl-N,N'-di(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine), DFLDPBi (4,4'-bis[N-(9,9-dimethylfluorene-2-methyl)-N-aniline]biphenyl), TCTA (tris(4-carbazole-9-ylphenyl)amine), TAPC (4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline]), etc.

[0234] Electron blocking layer 322 also has good hole transport characteristics and can be red, green, or blue. It can be an aromatic amine or carbazole material, such as CBP (4,4'-bis(N-carbazole)-1,1'-biphenyl) or PCzPA (9-phenyl-3-[4-(10-phenyl-9-anthrayl)phenyl]-9h-carbazole).

[0235] The organic light-emitting layer 330 can be composed of a single light-emitting material, or it can include a host material and a dopant material. Optionally, the organic light-emitting layer 330 is composed of a host material and a dopant material. Holes and electrons injected into the organic light-emitting layer 330 can recombine in the organic light-emitting layer 330 to form excitons. The excitons transfer energy to the host material, and the host material transfers energy to the dopant material, thereby enabling the dopant material to emit light.

[0236] The organic light-emitting layer 330 can be a phosphorescent host and a phosphorescent dopant, or a fluorescent host and a fluorescent dopant. Furthermore, each host material can contain one material or a mixture of two or more materials.

[0237] Specifically, the main material of the blue organic light-emitting layer can be selected from anthracene derivatives such as ADN (9,10-bis(2-naphthyl)anthracene) and MADN (3-tert-butyl-9,10-bis(2-naphthyl)anthracene); the doping material can be pyrene derivatives, fluorene derivatives, perylene derivatives, styrene amine derivatives, metal complexes, etc., such as TBPe (potassium tetrabromophenolphthalein ethyl ester), BDAVBi (4,4''-bis[4-(diphenylamino)styrene]biphenyl), DPAVBi (4,4'-bis[4-(di-p-tolylamino)styrene]biphenyl), FIrpic (bis(4,6-difluorophenylpyridine-N,C2)pyridinecarboxyiridium), etc.

[0238] The main material for the green organic light-emitting layer can be selected from coumarin dyes, quinacridone copper derivatives, polycyclic aromatic hydrocarbons, diamine anthracene derivatives, and carbazole derivatives, such as DMQA (N,N'-dimethylquinacridone), BA-NPB (N,N'-di-1-naphthyl-N,N'-diphenyl-[9,9'-bianthra]-10,10'-diamine; N1,N1'-diphenyl-N1,N1'-dinaphthyl-9,9'-bianthra-1,1'-diamine), Alq3 (8-hydroxyquinoline aluminum), CBP (4,4'-bis(N-carbazole)-1,1'-biphenyl), etc. Doping materials can be metal complexes, such as Ir(ppy)3 (tris(2-phenylpyridine)iridium | 94928-86-6) and Ir(ppy)2(acac) (di(2-phenylpyridine)iridium acetylacetonate), etc.

[0239] The main material for the red organic light-emitting layer can be selected from materials in the DCM series, such as DCJTB (2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinazine-9-yl)vinyl]-4H-pyran-4-ylidene} malononitrile), DCJTI (2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinazine-9-yl)vinyl]-4H-pyran-4-ylidene} malononitrile), etc. The doping material can be a metal complex, such as Ir(piq)2(acac) (:bis(1-phenyl-isoquinoline)(acetylacetone)iridium(III)), PtOEP (platinum(II)octaethylporphyrin), Ir(btp)2 (acac) (bis(2-(2'-benzothiophene)pyridine-N,C3')(acetylacetone)iridium), etc.

[0240] Electron blocking layer 322 and electron transport layer 350: generally aromatic heterocyclic compounds, such as imidazole derivatives, imidazopyridine derivatives, benzimidazole-phenanthridine derivatives, etc.; pyrimidine derivatives, triazine derivatives, etc.; quinoline derivatives, isoquinoline derivatives, phenanthreneline derivatives, etc., containing nitrogen-containing six-membered ring structures (including compounds with phosphine oxide substituents on the heterocycle). For example: OXD-7 (2,2'-(1,3-phenyl)bis[5-(4-tert-butyl) (3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole), p-EtTAZ (3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenyl)-1,2,4-triazole), BPhen (4,7-diphenyl-1,10-phenanthroline), TPBi (1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene), etc.

[0241] Furthermore, the light-emitting functional layer 300 may also include an electron injection layer 360 disposed between the cathode and the electron transport layer 350. The electron injection layer 360 is preferably a material with electron transport capability and also has the effect of injecting electrons from the cathode, and has excellent thin film forming capability. It is generally an alkali metal or a metal, such as LiF, Yb, Mg, Ca or their compounds.

[0242] like Figure 2 As shown, in some embodiments of this disclosure, the capping layer 400 includes a first capping layer 410 and a second capping layer 420 stacked along a direction away from the first electrode layer. The first capping layer 410 contains the first capping layer material, and the second capping layer 420 contains the second capping layer material. The molecular orientation of the first capping layer 410 is between -0.5 and -0.2. Specifically, it can be -0.5, -0.45, -0.4, -0.35, -0.3, -0.25, or -0.2, but is not limited thereto.

[0243] The ordered orientation of molecules is one of the most important properties of thin films in small-molecule organic optoelectronic materials. There are generally two types of molecular orientation relative to the substrate: upright orientation and parallel orientation. In organic light-emitting devices (OLEDs), photons are emitted outward from the organic light-emitting layer, and most are lost due to total internal reflection. Changing the orientation of organic light-emitting molecules can alter the emission angle of the emitting dipoles, thereby reducing total internal reflection and allowing more photons to be emitted effectively. Horizontal orientation of emitting molecules improves the optical performance of OLEDs because the direction of molecular emission is generally perpendicular to the molecular orientation. Therefore, ordered molecules along a specific direction imply a specific emission direction, which can improve device efficiency. Molecular orientation not only affects the optical properties of emitting molecules but also their electrical properties. Horizontally oriented molecules often have better electron mobility, which can also improve device efficiency. With the gradual development of organic optoelectronic technology, especially in the fields of organic light-emitting devices and organic display technology, the issue of organic molecular orientation has gradually attracted attention, leading to the development of methods for measuring and characterizing organic molecular orientation.

[0244] A common method for testing molecular orientation is to measure and calculate the order parameter S using an ellipsometry to characterize changes in molecular orientation in thin films, such as the first capping layer. The formula for calculating molecular orientation is as follows:

[0245]

[0246] This represents the angle between the molecular dipole axis and the normal to the base plane; Indicates the extinction coefficient in the vertical direction; This represents the extinction coefficient in the horizontal direction.

[0247] This disclosure also provides a display device, including the aforementioned organic light-emitting device. The display device can be: a mobile phone, tablet computer, television, monitor, laptop computer, digital photo frame or navigator, or any other product or component with display function.

[0248] The organic light-emitting devices provided in this disclosure will be described in detail below, based on specific experimental data and other information.

[0249] Coating material property testing

[0250] Refractive index

[0251] Refractive index is an important physical parameter of the coating material, and its magnitude directly determines the optical coupling efficiency of the device.

[0252] The refractive index was determined using an ellipsometer; the instrument scanning range was 245–1000 nm; a thin film was deposited on a silicon wafer with a film thickness of 50 nm. The refractive indices of the first capping layer material at different wavelengths are shown in Table 1, and the refractive indices of the second capping layer material at different wavelengths are shown in Table 2.

[0253] Table 1

[0254]

[0255] As can be seen from the data in Table 1, the first capping layer material has a higher refractive index. Comparing compounds 1-1 and 1-5, it can be seen that the more benzene rings contained in the structure shown in chemical formula 1-1, the higher the refractive index of the corresponding material molecule. Comparing compounds 1-5 and 1-6, it can be seen that the more structures shown in chemical formula 1-2 the material molecule contains, the higher the refractive index of the corresponding material molecule.

[0256] Table 2

[0257]

[0258] As can be seen from the data in Table 2, the refractive index of the second capping layer material is lower. At a wavelength of 460 nm, the refractive index of the first capping layer material is at least 0.35 greater than that of the second capping layer material; at a wavelength of 530 nm, the refractive index of the first capping layer material is at least 0.42 greater than that of the second capping layer material; and at a wavelength of 620 nm, the refractive index of the first capping layer material is at least 0.4 greater than that of the second capping layer material.

[0259] absorption coefficient

[0260] The absorption coefficient was measured using an ellipsometer; the instrument scanning range was 245–1000 nm; a thin film was deposited on a silicon wafer with a film thickness of 50 nm. The absorption coefficients of the first capping layer material at different wavelengths are shown in Table 3, and the absorption coefficients of the second capping layer material at different wavelengths are shown in Table 4.

[0261] Table 3

[0262]

[0263] Table 4

[0264]

[0265] As can be seen from the data in Tables 3 and 4, the first and second capping layer materials of this disclosure have particularly good absorption at 430 nm or shorter wavelengths, and almost no absorption at 430 nm or longer wavelengths. Such materials have very small absorption in red, green and blue light, which will not affect the light output of the device, while having strong absorption at 430 nm or shorter wavelengths. This can fully absorb the external ultraviolet light, prevent ultraviolet light from damaging the light-emitting device, and thus improve the performance of the device.

[0266] stability

[0267] The glass transition temperature (Tg) determines the thermal stability of the material during vapor deposition; the higher the Tg, the better the thermal stability of the material.

[0268] The measuring instrument was a DSC differential scanning calorimeter; the test atmosphere was nitrogen, the heating rate was 10℃ / min, and the temperature range was 50~300℃. The glass transition temperatures (Tg) of the first and second capping materials disclosed in this invention are shown in Table 5.

[0269] Table 5

[0270]

[0271] As shown in Table 5, the first and second cover layer materials in this disclosure have high glass transition temperatures, which are beneficial to improving the thermodynamic stability of the materials. During the vapor deposition process, the materials do not undergo cracking changes, which is a basic condition for the materials to be vapor deposited and maintain a long lifespan.

[0272] Other film material physical property testing

[0273] Refractive index

[0274] The determination method is the same as that for the determination of the refractive index of the capping layer material. The refractive indices of the hole transport layer (HTL), organic light-emitting layer (EML), and electron transport layer (ETL) are shown in Table 6.

[0275] Table 6

[0276]

[0277] BEML, GEML, and REML refer to the organic light-emitting layer 330 for blue light devices, the organic light-emitting layer 330 for green light devices, and the organic light-emitting layer 330 for red light devices, respectively.

[0278] The structure of the materials used in each membrane layer can be found in Table 7.

[0279] Device Examples

[0280] Fabrication process of blue light device Example 1: The pre-prepared ITO substrate is cleaned and dried; hole injection layer (HIL), hole transport layer (HTL), and electron blocking layer (EBL) are sequentially deposited on the anode; then organic light-emitting layer (BH1) is deposited; electron blocking layer (HBL), electron transport layer (ETL), and electron injection layer (EIL) are deposited on the organic light-emitting layer; then the cathode is deposited. A high-refractive-index first capping layer is deposited on the cathode; and a second capping layer (as disclosed herein) is deposited on top of the first capping layer. The device structure is as follows:

[0281] ITO / HIL(10nm) / HTL(100nm) / EBL(10nm) / BH:BD(20nm,5%) / HBL(5nm) / ETL:LIQ(30nm, 50%) / EIL(Yb)(1nm) / Mg:Ag 13nm / CPL1 200nm / CPL2 300nm

[0282] Preparation process of Examples 2-4:

[0283] Replace the first and second cover layer materials in Example 1 with the data in Table 8, while keeping everything else unchanged.

[0284] Preparation process of Comparative Example 1:

[0285] Replace the first cover layer material in Example 1 with CP1, remove the second cover layer material, and keep everything else the same.

[0286] The material structures in the embodiments are shown in Table 7.

[0287] Table 7

[0288]

[0289] For the organic light-emitting device prepared as described above, at 20 mA / cm 2 The performance of the device was analyzed under the specified conditions, and the results are shown in Table 8.

[0290] Table 8

[0291]

[0292] The values ​​in Table 8 are percentages relative to the comparative examples, with the examples used as a reference. Compared to the light-emitting device prepared in Comparative Example 1, the light-emitting devices prepared in Examples 1 to 4 using the compound disclosed herein as the capping layer 400 have lower driving voltages, higher luminous efficiency, and longer lifespans.

[0293] It should be understood that this disclosure is not limited to the detailed structure and arrangement of the components presented in this specification. This disclosure is capable of other embodiments and can be implemented and performed in various ways. The foregoing variations and modifications fall within the scope of this disclosure. It should be understood that this disclosure, as disclosed and defined in this specification, extends to all alternative combinations of two or more individual features mentioned or apparent in the text and / or drawings. All these different combinations constitute multiple alternative aspects of this disclosure. The embodiments described in this specification illustrate the best known mode for implementing this disclosure and will enable those skilled in the art to utilize this disclosure.

Claims

1. An organic light-emitting device, characterized in that, It includes a first electrode layer, a light-emitting functional layer, a second electrode layer, and a cover layer stacked sequentially, wherein the cover layer includes a first cover layer material and a second cover layer material; The first cover layer material and the second cover layer material satisfy the following: n1(λ1)-n2(λ1)≥0.2, 440nm≤λ1≤480nm; n1(λ2)-n2(λ2)≥0.1, 500nm≤λ2≤550nm; n1(λ3)-n2(λ3)≥0.1, 600nm≤λ3≤640nm; The light-emitting functional layer includes a hole transport layer, an organic light-emitting layer, and an electron transport layer sequentially stacked along a direction away from the first electrode layer, wherein the hole transport layer, the organic light-emitting layer, and the electron transport layer satisfy the following: 0.1≤n3(λ1)-n4(λ1)≤0.8; 0.1≤n3(λ2)-n4(λ2)≤0.8; 0.1≤n3(λ3)-n4(λ3)≤0.8; 0.1≤n5(λ1)-n4(λ1)≤0.8; 0.1≤n5(λ2)-n4(λ2)≤0.8; 0.1≤n5(λ3)-n4(λ3)≤0.8; Wherein, λ1, λ2, and λ3 represent different wavelength ranges of light; n1 represents the refractive index of the first cover layer material, and n2 represents the refractive index of the second cover layer material; n3 represents the refractive index of the hole transport layer, n4 represents the refractive index of the organic light-emitting layer, and n5 represents the refractive index of the electron transport layer. The first covering layer material is compound 1-1 or compound 1-2; Compound 1-1 Compounds 1-2 The second coating material is compound 2-1; Compound 2-1.

2. The organic light-emitting device according to claim 1, characterized in that, The light-emitting functional layer further includes an electron blocking layer and a hole blocking layer. The electron blocking layer is disposed between the hole transport layer and the organic light-emitting layer, and the hole blocking layer is disposed between the organic light-emitting layer and the electron transport layer. The hole blocking layer and the electron transport layer satisfy the following: 0.4 eV≤LUMO(HBL)-LUMO(ETL)≤1 eV; The electron blocking layer and the hole transport layer satisfy the following: 0.3 eV≤HOMO(HTL) - HOMO(EBL)≤1 eV; Wherein, LUMO (HBL) is the lowest unoccupied molecular orbital LUMO energy level of the hole blocking layer material, and LUMO (ETL) is the lowest unoccupied molecular orbital LUMO energy level of the electron transport layer material; HOMO (HTL) is the highest occupied molecular orbital HOMO level of the hole transport layer material, and HOMO (EBL) is the highest occupied molecular orbital HOMO level of the electron blocking layer material.

3. The organic light-emitting device according to claim 2, characterized in that, The organic light-emitting layer material comprises a host material and a dopant material; The bulk material of the organic light-emitting layer and the hole-blocking layer satisfy the following: T1(HBL) > T1(Host); The bulk material of the organic light-emitting layer and the electron-blocking layer satisfy the following: T1(EBL) > T1(Host); Wherein, T1(HBL) is the lowest triplet energy of the hole blocking layer material, T1(EBL) is the lowest triplet energy of the electron blocking layer material, and T1(Host) is the lowest triplet energy of the organic light-emitting layer host material.

4. The organic light-emitting device according to claim 3, characterized in that, The host material and the dopant material of the organic light-emitting layer satisfy the following: T1(Dopant)>T1(Host); S1(Host)>S1(Dopant); Wherein, T1 (Dopant) is the lowest triplet excitation energy of the organic light-emitting layer doped material, S1 (Host) is the lowest singlet excitation energy of the organic light-emitting layer host material, and S1 (Dopant) is the lowest singlet excitation energy of the organic light-emitting layer doped material.

5. The organic light-emitting device according to claim 1, characterized in that, The hole mobility and electron mobility of the organic light-emitting layer satisfy the following: 0.01<μh(EML) / μe(EML)≤100; Wherein, μh(EML) is the hole mobility of the organic light-emitting layer, and μe(EML) is the electron mobility of the organic light-emitting layer.

6. The organic light-emitting device according to claim 1, characterized in that, The light-emitting functional layer further includes a hole injection layer, which is disposed between the first electrode layer and the hole transport layer; The resistivity of the hole injection layer is not less than 100Ω. m.

7. The organic light-emitting device according to claim 1, characterized in that, The cover layer includes a first cover layer and a second cover layer stacked along a direction away from the first electrode layer, wherein the first cover layer contains the first cover layer material and the second cover layer contains the second cover layer material; The molecular orientation of the first covering layer is between -0.5 and -0.

2.

8. A display device, characterized in that, Including the organic light-emitting device as described in any one of claims 1-7.

Images