Organic light emitting device, display device

Abstract

Provided are an organic light-emitting device and a display device. The organic light-emitting device comprises a light-emitting layer (500) comprising a first host material, a second host material, at least one auxiliary material and at least one dopant material; the first host material and the second host material form a first composite transport material; the auxiliary material and the second host material form a second composite transport material; S1(A)>S1(CH)>S1(C); T1(A)>T1(CH)>T1(C); S1(A) is the lowest singlet energy of the host material, S1(CH) is the lowest singlet energy of the composite transport material, and S1(C) is the lowest singlet energy of the dopant material; T1(A) is the lowest triplet energy of the host material, T1(CH) is the lowest triplet energy of the composite transport material, and T1(C) is the lowest triplet energy of the dopant material. Dexter energy transfer is inhibited, energy loss is reduced, and device efficiency is improved.

Description

Technical Field

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

[0002] 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 into the light-emitting layer from the anode and cathode, respectively. When electrons and holes meet in the light-emitting layer, they recombine to generate excitons. These excitons emit light as they transition from the excited state to the ground state.

[0003] Currently, OLEDs typically use phosphorescent materials as their light-emitting materials. However, phosphorescent materials contain precious metal atoms, resulting in high material costs and pollution risks, thus hindering low-cost display applications. Related technologies have proposed using purely organic light-emitting materials with thermally active delayed fluorescent (TADF) properties, but these structures suffer from problems such as triplet exciton annihilation.

[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 device that effectively suppresses Dexter energy transfer, reduces energy loss, and thereby improves device efficiency.

[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 light-emitting layer, said light-emitting layer comprising a first host material, a second host material, at least one auxiliary material and at least one doping material;

[0008] The first main material and the second main material form a first composite transport material; the auxiliary material and the second main material form a second composite transport material.

[0009] The first host material, the second host material, the first composite transport material, the second composite transport material, and the doped material satisfy the following conditions:

[0010] S1(A)>S1(CH)>S1(C);

[0011] T1(A)>T1(CH)>T1(C);

[0012] Wherein, S1(A) is the lowest singlet energy of the first host material or the second host material, S1(CH) is the lowest singlet energy of the first composite transport material or the second composite transport material, and S1(C) is the lowest singlet energy of the doped material.

[0013] T1(A) is the lowest triplet energy of the first host material or the second host material, T1(CH) is the lowest triplet energy of the first composite transport material or the second composite transport material, and T1(C) is the lowest triplet energy of the doped material.

[0014] In one exemplary embodiment of this disclosure, the first main material, the second main material, the first composite transport material, the second composite transport material, and the auxiliary material satisfy the following conditions:

[0015] S1(A)>S1(CH1)>S1(CH2), S1(A)>S1(B)>S1(CH2);

[0016] T1(A)>T1(CH1)>T1(CH2), T1(A)>T1(B)>T1(CH2);

[0017] Wherein, S1(CH1) is the lowest singlet energy of the first composite transport material; S1(CH2) is the lowest singlet energy of the second composite transport material;

[0018] S1(B) is the lowest triplet energy of the auxiliary material; T1(B) is the lowest triplet energy of the auxiliary material;

[0019] T1(CH1) is the lowest triplet energy of the first composite transport material; T1(CH2) is the lowest triplet energy of the second composite transport material.

[0020] In one exemplary embodiment of this disclosure, the first main material, the second main material, and the auxiliary material satisfy the following conditions:

[0021] |HOMO(A2)-LUMO(A1)|≥3.5eV, |HOMO(A1)-LUMO(A2)|≤3eV, |HOMO(B)-LUMO(A2)|≥2.3eV;

[0022] Wherein, HOMO(A1) is the highest occupied molecular orbital HOMO energy level of the first host material, and LUMO(A1) is the lowest unoccupied molecular orbital LUMO energy level of the first host material.

[0023] HOMO(A2) is the highest occupied molecular orbital HOMO energy level of the second host material, and LUMO(A2) is the lowest unoccupied molecular orbital LUMO energy level of the second host material;

[0024] HOMO(B) is the highest occupied molecular orbital HOMO energy level of the auxiliary material, and LUMO(B) is the lowest unoccupied molecular orbital LUMO energy level of the auxiliary material.

[0025] In one exemplary embodiment of this disclosure, the first main material, the second main material, and the auxiliary material satisfy the following conditions:

[0026] |HOMO(A1)|>|HOMO(B)|≥5.6eV;

[0027] |LUMO(B)|>|LUMO(A2)|≥1eV.

[0028] In one exemplary embodiment of this disclosure, the first main material and the auxiliary material are hole-type materials, and the second main material is an electronic-type material;

[0029] The hole migration rate of the first main material is higher than that of the auxiliary material.

[0030] In one exemplary embodiment of this disclosure, the difference between the hole mobility and electron mobility of the auxiliary material does not exceed two orders of magnitude.

[0031] In one exemplary embodiment of this disclosure, the first composite transport material and the second composite transport material satisfy the following conditions:

[0032] ΔE ST (CH)≤0.3eV;

[0033] Where, ΔE ST (CH) is the energy level difference between the lowest singlet state energy and the lowest triplet state energy of the first composite transport material, or the energy level difference between the lowest singlet state energy and the lowest triplet state energy of the second composite transport material.

[0034] In one exemplary embodiment of this disclosure, the auxiliary material is a delayed fluorescence material, and the auxiliary material satisfies the following conditions:

[0035] ΔEST (B)≤0.3eV;

[0036] Where, ΔE ST (B) is the energy difference between the lowest singlet energy and the lowest triplet energy of the auxiliary material.

[0037] In an exemplary embodiment of this disclosure, the emission spectrum of the second composite transport material overlaps with the absorption spectrum of the doped material, and the ratio of the overlapping area to the area of ​​the emission spectrum of the second composite material is a, where a ≥ 30%.

[0038] The emission spectrum of the auxiliary material overlaps with the absorption spectrum of the doped material, and the ratio of the overlapping area to the area of ​​the emission spectrum of the auxiliary material is b, where b ≥ 30%.

[0039] In one exemplary embodiment of this disclosure, the at least one auxiliary material includes a first auxiliary material and a second auxiliary material;

[0040] The second composite transmission material includes a first sub-composite transmission material and a second sub-composite transmission material;

[0041] The first auxiliary material and the second main material form the first sub-composite transport material, and the second auxiliary material and the second main material form the second sub-composite transport material;

[0042] The second auxiliary material and the second sub-composite transport material satisfy the following requirements:

[0043] S1(B2)>S1(CH22);

[0044] T1(B2)>T1(CH22);

[0045] Wherein, S1(B2) is the lowest triplet energy of the second auxiliary material; T1(B2) is the lowest triplet energy of the second auxiliary material;

[0046] S1(CH22) is the lowest triplet energy of the second sub-composite transport material; T1(CH22) is the lowest triplet energy of the second sub-composite transport material.

[0047] In one exemplary embodiment of this disclosure, the first composite transport material, the first auxiliary material, the second auxiliary material, the first sub-composite transport material, and the second sub-composite transport material satisfy the following conditions:

[0048] S1(CH1)>S1(B2)>S1(B1)>S1(CH21)>S1(CH22);

[0049] T1(CH1)>T1(B2)>T1(B1)>T1(CH21)>T1(CH22);

[0050] Wherein, S1(CH1) is the lowest singlet energy of the first composite transport material; S1(CH2) is the lowest singlet energy of the second composite transport material;

[0051] S1(B1) is the lowest triplet energy of the second auxiliary material; T1(B1) is the lowest triplet energy of the second auxiliary material;

[0052] S1(CH21) is the lowest triplet energy of the first sub-composite transport material; T1(CH21) is the lowest triplet energy of the first sub-composite transport material.

[0053] In one exemplary embodiment of this disclosure, the first auxiliary material and the second auxiliary material satisfy the following conditions:

[0054] |HOMO(B2)|-|HOMO(B1)|≤0.5eV;

[0055] Wherein, HOMO(B1) is the highest occupied molecular orbital HOMO energy level of the first auxiliary material, and HOMO(B2) is the highest occupied molecular orbital HOMO energy level of the second auxiliary material.

[0056] In one exemplary embodiment of this disclosure, the doping material is selected from fluorescent materials containing boron and nitrogen.

[0057] In one exemplary embodiment of this disclosure, the first host material is selected from cavitation materials containing one or more groups selected from carbazole group, spirofluorene group, biphenyl group, and acridine group.

[0058] In one exemplary embodiment of this disclosure, the second host material is selected from electronic materials containing one or more groups selected from cyano groups, pyridine groups, pyrimidine groups, triazine groups, and phospho groups.

[0059] In one exemplary embodiment of this disclosure, the auxiliary material is selected from materials containing electron-donating and electron-withdrawing groups. The electron-donating group is selected from one or more of carbazole group, phenoxazine group, acridine group, fluorene group, dibenzothiophene group, and dibenzofuran group. The electron-withdrawing group is selected from one or more of cyano group, triazine group, and phosphorooxy group.

[0060] In one exemplary embodiment of this disclosure, the organic light-emitting device further includes a cathode and an anode, and the light-emitting layer is disposed between the anode and the cathode;

[0061] The light-emitting layer includes a first light-emitting layer and a second light-emitting layer, wherein the second light-emitting layer is disposed on the side of the first light-emitting layer away from the anode;

[0062] The first light-emitting layer comprises the first main material, and the second light-emitting layer comprises the second main material;

[0063] At least one of the first light-emitting layer and the second light-emitting layer contains the auxiliary material;

[0064] At least one of the first light-emitting layer and the second light-emitting layer contains the doped material.

[0065] In one exemplary embodiment of this disclosure, the organic light-emitting device further includes a cathode and an anode, and the light-emitting layer is disposed between the anode and the cathode;

[0066] The light-emitting layer includes a first light-emitting layer and a second light-emitting layer, wherein the second light-emitting layer is disposed on the side of the first light-emitting layer away from the anode;

[0067] The first light-emitting layer comprises the first main material and the first auxiliary material, and the second light-emitting layer comprises the second main material and the second auxiliary material;

[0068] At least one of the first light-emitting layer and the second light-emitting layer contains the doped material.

[0069] According to a second aspect of this disclosure, a display device is provided, comprising an organic light-emitting device as described in the first aspect.

[0070] The organic light-emitting device disclosed herein comprises a first host material and a second host material forming a first composite transport material, and an auxiliary material and a second host material forming a second composite transport material. Both the first and second composite transport materials help to disperse excitons, suppress nonradiative transitions of triplet excitons, reduce the degradation of materials caused by triplet quenching, improve material stability, and perform radiative transitions to emit light through Forster energy transfer to the doped material, effectively suppressing Dexter energy transfer, reducing energy loss, and thereby improving device efficiency. Attached Figure Description

[0071] 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.

[0072] Figure 1 This is a schematic diagram of the organic light-emitting device structure in an exemplary embodiment of this disclosure;

[0073] Figure 2 This is a schematic diagram of the light-emitting layer structure in an exemplary embodiment of this disclosure;

[0074] Figure 3 This is a schematic diagram of the light-emitting layer structure in another exemplary embodiment of this disclosure;

[0075] Figure 4 This is another schematic diagram of the structure of the light-emitting layer in another exemplary embodiment of this disclosure;

[0076] Figure 5 This is a schematic diagram of the energy transfer structure in an exemplary embodiment of this disclosure;

[0077] Figure 6 These are the emission and absorption spectra of A1-2 and A2-7 in the exemplary embodiments of this disclosure;

[0078] Figure 7 These are the emission and absorption spectra of B-3 and A2-7 in the exemplary embodiments of this disclosure;

[0079] Figure 8 These are emission spectra of B-5 and A2-7 in an exemplary embodiment of this disclosure. Detailed Implementation

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] TADF (Transient Atomizing Diode) materials are the third generation of organic light-emitting materials, following organic fluorescent and organic phosphorescent materials. They have seen rapid development in recent years and represent a promising organic light-emitting diode (OLED) technology. TADF materials possess a small singlet-triplet energy level difference (ΔEST), allowing triplet excitons to be converted into singlet excitons for emission via reverse intersystem crossing (RISC). Utilizing both singlet and triplet excitons formed under electrical excitation, the internal quantum efficiency of the device can reach 100%. The material structure is controllable, its properties are stable, and it is inexpensive, requiring no precious metals, thus showing promising application prospects. Although theoretically, TADF materials can achieve 100% exciton utilization, existing single-layer or double-layer light-emitting layer structures suffer from severe non-radiative attenuation and triplet exciton annihilation.

[0086] like Figures 1 to 3 As shown, this embodiment of the present disclosure provides an organic light-emitting device, including a light-emitting layer 500. The light-emitting layer 500 includes a first host material, a second host material, at least one auxiliary material, and at least one dopant material. The first host material and the second host material form a first composite transport material; the auxiliary material and the second host material form a second composite transport material; the first host material, the second host material, the first composite transport material, the second composite transport material, and the dopant material satisfy the following conditions:

[0087] S1(A)>S1(CH)>S1(C);

[0088] T1(A)>T1(CH)>T1(C);

[0089] Wherein, S1(A) is the lowest singlet energy of the first host material or the second host material, S1(CH) is the lowest singlet energy of the first composite transport material or the second composite transport material, and S1(C) is the lowest singlet energy of the doped material; T1(A) is the lowest triplet energy of the first host material or the second host material, T1(CH) is the lowest triplet energy of the first composite transport material or the second composite transport material, and T1(C) is the lowest triplet energy of the doped material.

[0090] The organic light-emitting device disclosed herein comprises a first host material and a second host material forming a first composite transport material, and an auxiliary material and a second host material forming a second composite transport material. Both the first and second composite transport materials help to disperse excitons, suppress nonradiative transitions of triplet excitons, reduce the degradation of materials caused by triplet quenching, improve material stability, and perform radiative transitions to emit light through Forster energy transfer to the doped material, effectively suppressing Dexter energy transfer, reducing energy loss, and thereby improving device efficiency.

[0091] 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:

[0092] like Figure 1 As shown, the organic light-emitting device provided in this disclosure includes an anode 100, a cathode 900, and a light-emitting layer 600, with the light-emitting layer 500 disposed between the anode 100 and the cathode 900. The light-emitting layer 500 includes a first host material, a second host material, at least one auxiliary material, and at least one dopant material. In some embodiments of this disclosure, the organic light-emitting device further includes a hole injection layer (HIL) 200, a hole transport layer (HTL) 300, a first exciton blocking layer (EBL) 400, a second exciton blocking layer (HBL) 600, an electron transport layer (ETL) 700, and an electron injection layer (EIL) 800. The hole injection layer 200 (HIL), the hole transport layer (HTL) 300, and the first exciton blocking layer (EBL) 400 are located between the anode 100 and the light-emitting layer 500, while the second exciton blocking layer (HBL) 600, the electron transport layer (ETL) 700, and the electron injection layer (EIL) 800 are located between the light-emitting layer 500 and the cathode 900. Hole injection layer 200 is used to lower the potential barrier for holes injected from the anode 100, enabling holes to be effectively injected from the anode 100 into the light-emitting layer 500, thereby improving hole injection efficiency. Hole transport layer 300 is used to achieve directional and controlled migration of injected holes. First exciton blocking layer 400 is used to form a migration barrier for electrons or excitons, preventing electrons or excitons from migrating out of the light-emitting layer 500. Light-emitting layer 500 is used to enable electrons and holes to recombine and form excitons to emit light. Second exciton blocking layer 600 is used to form a migration barrier for holes or excitons, preventing holes or excitons from migrating out of the light-emitting layer 500. Electron transport layer 700 is used to achieve directional and controlled migration of injected electrons. Electron injection layer 800 is used to lower the potential barrier for electrons injected from the cathode 900, enabling electrons to be effectively injected from the cathode 900 into the light-emitting layer 500.

[0093] In an exemplary embodiment, the anode 100 may be made of a material with a high work function. For bottom-emitting OLEDs, the anode 100 may be made of a transparent oxide material, such as indium tin oxide (ITO) or indium zinc oxide (IZO), and the thickness of the anode may be approximately 80 nm to 200 nm. For top-emitting OLEDs, the anode 100 may be made of a composite structure of metal and transparent oxide, such as Ag / ITO or Ag / IZO, and the thickness of the metal layer in the anode 100 may be approximately 80 nm to 100 nm, and the thickness of the transparent oxide in the anode 100 may be approximately 5 nm to 20 nm, so that the average reflectance of the anode 100 in the visible light region is approximately 85% to 95%.

[0094] In an exemplary embodiment, for a top-emitting OLED, the cathode 900 can be made of a metallic material, formed by a vapor deposition process. The metallic material can be magnesium (Mg), silver (Ag), or aluminum (Al), or an alloy material, such as a Mg:Ag alloy, with a Mg:Ag ratio of approximately 3:7 to 1:9. The thickness of the cathode 900 can be approximately 10 nm to 20 nm, resulting in an average transmittance of approximately 50% to 60% at a wavelength of 530 nm. For a bottom-emitting OLED, the cathode 900 can be made of magnesium (Mg), silver (Ag), aluminum (Al), or a Mg:Ag alloy. The thickness of the cathode 900 can be approximately greater than 80 nm, giving the cathode 900 good reflectivity.

[0095] In an exemplary embodiment, the hole injection layer 200 may be made of a single material, such as 4-isopropyl-4'-methyldiphenyliodonium tetra(pentafluorophenyl)borate and / or dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarboxynitrile (HAT-CN), CuPc, etc., or may be made of doped materials, such as p-type doping of the hole transport material, with a p-doping ratio of approximately 0.5% to 10%, such as N,N'-di(naphthyl-1-yl)-N,N'-diphenyl-benzidine (NPB): 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone (F4-TCNQ), 4,4'-cyclohexylenebis[N,N-bis(4-methylphenyl)aniline] (TAPC): MnO3, etc. The thickness of the hole injection layer 200 can be approximately 5 nm to 20 nm.

[0096] In an exemplary embodiment, the hole transport layer 300 may be made of a material with high hole mobility, such as carbazole, methyl fluorene, spirofluorene, dibenzothiophene, or furan, and formed by a vapor deposition process. The thickness of the hole transport layer 300 may be approximately 100 nm to 140 nm.

[0097] In an exemplary embodiment, the thickness of the first exciton blocking layer 400 may be approximately 1 nm to 10 nm, and it is configured to transmit holes, block electrons, and block excitons generated within the light-emitting layer.

[0098] In an exemplary embodiment, the thickness of the second exciton blocking layer 600 is approximately 2 nm to 10 nm, and it is configured to block holes and excitons generated within the light-emitting layer.

[0099] In an exemplary embodiment, the electron transport layer 700 may be prepared by blending thiophene, imidazole or azazine derivatives with quinoline lithium, wherein the proportion of quinoline lithium is about 30% to 70%, and the thickness of the electron transport layer 700 may be about 20 nm to 70 nm.

[0100] In an exemplary embodiment, the electron injection layer 800 may be formed by a vapor deposition process using materials such as lithium fluoride (LiF), lithium 8-hydroxyquinoline (LiQ), ytterbium (Yb), or calcium (Ca), and the thickness of the electron injection layer 800 may be approximately 0.5 nm to 2 nm.

[0101] like Figures 2 to 4 As shown, the light-emitting layer 600 includes a first host material, at least one auxiliary material, and at least one dopant material. The first host material and the second host material form a first composite transport material, and the auxiliary material and the second host material form a second composite transport material. The first composite transport material, the second composite transport material, and the auxiliary material can be used to disperse excitons or transport exciton energy to the dopant material, so that the dopant material emits light.

[0102] The first host material, the second host material, the first composite transport material, the second composite transport material, and the doped material satisfy the following conditions:

[0103] S1(A)>S1(CH)>S1(C);

[0104] T1(A)>T1(CH)>T1(C);

[0105] Wherein, S1(A) is the lowest singlet energy of the first host material or the second host material, S1(CH) is the lowest singlet energy of the first composite transport material or the second composite transport material, and S1(C) is the lowest singlet energy of the doped material.

[0106] T1(A) is the lowest triplet energy of the first host material or the second host material, T1(CH) is the lowest triplet energy of the first composite transport material or the second composite transport material, and T1(C) is the lowest triplet energy of the doped material.

[0107] In this disclosure, excitons can be generated on the first composite transport material, the second composite transport material, and the auxiliary material, thereby dispersing the excitons and preventing excessive concentration of excitons on any particular material. This reduces the quenching of triplet excitons due to excessive exciton concentration at a certain location, improving the luminous efficiency of the device. Furthermore, the minimum singlet and minimum triplet energies of the first and second composite transport materials are lower than those of the first and second host materials, but higher than those of the doped materials. This allows exciton energy to be transferred to the doped materials through multiple pathways, enabling radiative transition luminescence and improving device efficiency.

[0108] In some embodiments of this disclosure, the first main material, the second main material, the first composite transport material, the second composite transport material, and the auxiliary material satisfy the following conditions:

[0109] S1(A)>S1(CH1)>S1(CH2), S1(A)>S1(B)>S1(CH2);

[0110] T1(A)>T1(CH1)>T1(CH2), T1(A)>T1(B)>T1(CH2);

[0111] Wherein, S1(CH1) is the lowest singlet energy of the first composite transport material; S1(CH2) is the lowest singlet energy of the second composite transport material;

[0112] S1(B) is the lowest triplet energy of the auxiliary material; T1(B) is the lowest triplet energy of the auxiliary material;

[0113] T1(CH1) is the lowest triplet energy of the first composite transport material; T1(CH2) is the lowest triplet energy of the second composite transport material.

[0114] In this embodiment, exciton energy can be transferred to the doped material through multi-stage transport or multiple pathways. For example, since S1(A)>S1(CH1)>S1(CH2), S1(A)>S1(B)>S1(CH2); T1(A)T1(CH1)>T1(CH2), T1(A)T1(B)>T1(CH2), exciton energy can be transferred to the auxiliary material via the first composite transport material, and the auxiliary material can act as a material to transfer the exciton energy to the second composite transport material, and then to the doped material; or it can be transferred to the second composite transport material via the first composite transport material, and then to the doped material; or it can be directly transferred to the doped material via the first composite transport material. This multi-pathway transfer not only achieves the separation of the exciton recombination center and the luminescence center, but also makes the exciton energy more dispersed throughout the device, reducing triplet quenching and its deterioration on the material, thus improving the stability of the material and the efficiency of the device. In addition, the host material has a high minimum singlet or triplet energy, which confines the excitons in the composite transport material or auxiliary material, reduces exciton backflow, and avoids a decrease in luminescence efficiency.

[0115] In some embodiments of this disclosure, λpeak(CH1) < λpeak(CH2), λpeak(B) < λpeak(CH2);

[0116] Wherein, λpeak(CH1) is the wavelength of the strongest emission peak of the first composite transport material, λpeak(CH2) is the wavelength of the strongest emission peak of the second composite transport material, and λpeak(B) is the wavelength of the strongest emission peak of the auxiliary material.

[0117] In some embodiments of this disclosure, the first main material, the second main material, and the auxiliary materials satisfy the following conditions:

[0118] |HOMO(A2)-LUMO(A1)|≥3.5eV, |HOMO(A1)-LUMO(A2)|≤3eV, |HOMO(B)-LUMO(A2)|≥2.3eV;

[0119] Wherein, HOMO(A1) is the highest occupied molecular orbital HOMO energy level of the first host material, and LUMO(A1) is the lowest unoccupied molecular orbital LUMO energy level of the first host material; HOMO(A2) is the highest occupied molecular orbital HOMO energy level of the second host material, and LUMO(A2) is the lowest unoccupied molecular orbital LUMO energy level of the second host material; HOMO(B) is the highest occupied molecular orbital HOMO energy level of the auxiliary material, and LUMO(B) is the lowest unoccupied molecular orbital LUMO energy level of the auxiliary material.

[0120] In this embodiment, materials that meet the above-mentioned energy level range help the first host material and the second host material to form a first composite transport material, and the auxiliary material and the second host material to form a second composite transport material.

[0121] Furthermore, in some embodiments, |HOMO(A1)|>|HOMO(B)|≥5.6eV;

[0122] |LUMO(B)|>|LUMO(A2)|≥1eV.

[0123] In some embodiments of this disclosure, the first host material and the auxiliary material are hole-type materials, and the second host material is an electron-type material. The hole mobility of the first host material is higher than that of the auxiliary material to ensure the hole concentration in the light-emitting layer.

[0124] In some embodiments of this disclosure, the difference between the hole mobility and electron mobility of the auxiliary material does not exceed two orders of magnitude. When the hole mobility of the auxiliary material is greater than the electron mobility, the difference between the hole mobility and electron mobility can be m or m×10. 1 or m×10 2 , where m can be any value greater than 0 and less than 10.

[0125] In some embodiments of this disclosure, the first host material is selected from cavitation materials containing one or more groups selected from carbazole, spirofluorene, biphenyl, and acridine groups.

[0126] The carbazole group can be composed of carbazole. The specific group formed by losing one hydrogen atom is not limited in this disclosure;

[0127] The spirofluorene group can be composed of spirofluorene The specific form of the spirofluorene group formed by losing one hydrogen atom, or the subspirofluorene group formed by losing two hydrogen atoms, or the linking group formed by losing more hydrogen atoms, is not limited in this disclosure;

[0128] The biphenyl group can be composed of biphenyl The specific form of the biphenyl group formed by losing one hydrogen atom, or the biphenyl-like group formed by losing two hydrogen atoms, or the linking group formed by losing more hydrogen atoms, is not limited in this disclosure;

[0129] The acridine group can be composed of acridine The specific group formed by losing one hydrogen atom is not limited in this disclosure; it may be an acridine group formed by losing two hydrogen atoms, or a linking group formed by losing more than one hydrogen atom.

[0130] Furthermore, in this disclosure, the first host material may also be a cavitation material containing other groups, and the groups contained therein are not specifically limited in this disclosure.

[0131] In some embodiments of this disclosure, the first host material is selected from the group consisting of the following compounds:

[0132] In some embodiments of this disclosure, the second body is selected from electronic materials containing one or more groups selected from cyano groups, pyridine groups, pyrimidine groups, triazine groups, and phosphoro groups.

[0133] In this disclosure, the cyano group may be a cyano (-CN);

[0134] The pyridine group can be composed of pyridine The specific group formed by losing one hydrogen atom is not limited in this disclosure;

[0135] Pyrimidine can be composed of pyrimidine The specific group formed by losing one hydrogen atom is not limited in this disclosure;

[0136] The triazine group can be derived from triazine. The specific group formed by losing one hydrogen atom is not limited in this disclosure; it may be a triazine group formed by losing two hydrogen atoms, or a linking group formed by losing more than one hydrogen atom.

[0137] Furthermore, in this disclosure, the second host material may also be an electronic material containing other groups, and the groups contained therein are not specifically limited in this disclosure.

[0138] In some embodiments of this disclosure, the second body material is selected from the group consisting of the following structures:

[0139] In some embodiments of this disclosure, the first composite transport material and the second composite transport material satisfy ΔE ST (CH)≤0.3eV;

[0140] Where, ΔE ST (CH) is the energy level difference between the lowest singlet state energy and the lowest triplet state energy of the first composite transport material, or the energy level difference between the lowest singlet state energy and the lowest triplet state energy of the second composite transport material.

[0141] Preferably, ΔE ST (CH)≤0.2eV.

[0142] In some embodiments of this disclosure, the auxiliary material is a delayed fluorescence material, and the auxiliary material satisfies ΔE ST (B)≤0.3eV;

[0143] Where, ΔE ST (B) is the energy difference between the lowest singlet state energy and the lowest triplet state energy of the auxiliary material.

[0144] Preferably, ΔE ST (B)≤0.15eV.

[0145] like Figure 5 As shown, excitons formed when the ground state is excited are divided into two categories: singlet excitons and triplet excitons. According to the spin statistics rule, the ratio of singlet to triplet excitons is 25%:75%. In this disclosure, the energy difference between the first and second composite transport materials is small, exhibiting certain thermally activated delayed fluorescence (TADF) performance. Part of the triplet energy of the first and second composite transport materials can return to the singlet energy through reverse system-reinforced crossover (RISC), and then be transferred to the doped material via Foster Resonance Energy Transfer (FET). The first composite transport material can also transfer energy to the first auxiliary material or the second composite transport material. The auxiliary material is a delayed fluorescence material, and its triplet energy can also return to the singlet energy through reverse system-reinforced crossover, thus transferring energy to the second composite transport material or the doped material. In this way, the reverse intersystem jump process can transfer almost all the energy via the singlet state to the next stage energy transport material or dopant material through the Freud energy. The dopant material can simultaneously utilize singlet excitons and excitons transitioning from the triplet state to its own singlet state for luminescence. Throughout the luminescence process, Dexter energy transfer between triplet states is largely suppressed, reducing energy loss and improving device performance.

[0146] In some embodiments of this disclosure, the emission spectrum of the second composite transport material overlaps with the absorption spectrum of the doped material, and the ratio of the overlapping area to the area of ​​the emission spectrum of the second composite material is a, where a ≥ 30%; preferably, a ≥ 50%, such as 60% or 70%.

[0147] The emission spectrum of the auxiliary material overlaps with the absorption spectrum of the doped material, and the ratio of the overlapping area to the area of ​​the emission spectrum of the auxiliary material is b, where b ≥ 30%, preferably b ≥ 50%, such as 60% or 70%.

[0148] In some embodiments of this disclosure, the emission spectrum of the first composite transport material overlaps with the absorption spectrum of the doped material, and the ratio of the overlapping area to the area of ​​the emission spectrum of the first composite material is c, where c ≥ 20%.

[0149] Furthermore, c < b < a, to prevent exciton backflow and ensure the stepwise transfer of energy.

[0150] The larger the overlap area between the emission spectrum of the second composite transport material or auxiliary material and the absorption spectrum of the doped material, the more complete the energy transfer, the more complete the luminescence of the doped material, and the less energy quenching on the second composite transport material or auxiliary material, thereby improving exciton utilization, increasing efficiency, and improving device lifetime. This disclosure improves the luminous efficiency and lifetime of the device by setting the overlap area between the emission spectrum of the second composite transport material or auxiliary material and the absorption spectrum of the doped material to be greater than or equal to 30% of the emission spectrum of the second composite transport material or auxiliary material, preferably 50%.

[0151] like Figure 3 and Figure 4 As shown, in some embodiments of this disclosure, the light-emitting layer comprises two auxiliary materials, that is, at least one auxiliary material includes a first auxiliary material and a second auxiliary material;

[0152] The second composite transmission material includes a first sub-composite transmission material and a second sub-composite transmission material;

[0153] The first auxiliary material and the second main material form the first sub-composite transport material, and the second auxiliary material and the second main material form the second sub-composite transport material;

[0154] The second auxiliary material and the second sub-composite transmission material satisfy the requirements.

[0155] S1(B2)>S1(CH22); T1(B2)>T1(CH22);

[0156] Where S1(B2) is the lowest triplet energy of the second auxiliary material; T1(B2) is the lowest triplet energy of the second auxiliary material;

[0157] S1(CH22) is the lowest triplet energy of the second sub-composite transport material; T1(CH22) is the lowest triplet energy of the second sub-composite transport material.

[0158] In this embodiment, exciton energy can be transferred to the doped material through more pathways, which can further disperse the exciton energy transfer to a certain extent and alleviate the deterioration of the material.

[0159] In some embodiments of this disclosure, the first composite transport material, the first auxiliary material, the second auxiliary material, the first sub-composite transport material, and the second sub-composite transport material satisfy the following conditions:

[0160] S1(CH1)>S1(B2)>S1(B1)>S1(CH21)>S1(CH22);

[0161] T1(CH1)>T1(B2)>T1(B1)>T1(CH21)>T1(CH22);

[0162] Wherein, S1(CH1) is the lowest singlet energy of the first composite transport material; S1(CH2) is the lowest singlet energy of the second composite transport material;

[0163] S1(B1) is the lowest triplet energy of the second auxiliary material; T1(B1) is the lowest triplet energy of the second auxiliary material;

[0164] S1(CH21) is the lowest triplet energy of the first sub-composite transport material; T1(CH21) is the lowest triplet energy of the first sub-composite transport material.

[0165] In some embodiments of this disclosure, λpeak(B2) < λpeak(CH22);

[0166] Wherein, λpeak(B2) is the wavelength of the strongest emission peak of the second auxiliary material, and λpeak(CH22) is the wavelength of the strongest emission peak of the second sub-composite transport material.

[0167] In some embodiments of this disclosure, the first auxiliary material and the second auxiliary material satisfy the following conditions:

[0168] |HOMO(B2)|-|HOMO(B1)|≤0.5eV;

[0169] Preferably, |HOMO(B2)|-|HOMO(B1)|≤0.2eV;

[0170] Among them, HOMO(B1) is the highest occupied molecular orbital HOMO energy level of the first auxiliary material, and HOMO(B2) is the highest occupied molecular orbital HOMO energy level of the second auxiliary material.

[0171] In some embodiments of this disclosure, the auxiliary material is selected from materials containing electron-donating and electron-withdrawing groups. The electron-donating group is selected from one or more of carbazole group, phenoxazine group, acridine group, fluorene group, dibenzothiophene group, and dibenzofuran group, and the electron-withdrawing group is selected from one or more of cyano group, triazine group, and phosphoroxo group.

[0172] In this disclosure, the phenoxazine group is composed of phenoxazine. The specific group formed by losing one hydrogen atom is not limited in this disclosure; it may be a phenoxazine group formed by losing two hydrogen atoms, or a linking group formed by losing more than one hydrogen atom.

[0173] In this disclosure, the dibenzothiophene group is composed of a dibenzothiophene group. The specific group formed by losing one hydrogen atom is not limited in this disclosure; it may be a dibenzothiophene group formed by losing two hydrogen atoms, or a linking group formed by losing more hydrogen atoms.

[0174] In this disclosure, the dibenzofuran group is composed of dibenzofuran. The specific group formed by losing one hydrogen atom is not limited in this disclosure; it may be a dibenzofuran group formed by losing two hydrogen atoms, or a linking group formed by losing more hydrogen atoms.

[0175] In some embodiments of this disclosure, the auxiliary materials are selected from the group consisting of:

[0176]

[0177] In some embodiments of this disclosure, the light-emitting layer comprises two doping materials, i.e., at least one doping material includes a first doping material and a second doping material.

[0178] In some embodiments of this disclosure, the doping material is selected from fluorescent materials containing boron and nitrogen. The fluorescence quantum yield (PLQY) of the doping material is >80%, and the doping ratio in the emitting layer is no greater than 2%, preferably less than 1%. The doping ratio refers to the proportion of the doping material to the total of the host material, auxiliary material, and doping material.

[0179] Specifically, the doped material contains at least one nitrogen atom, and the boron is tri- or tetra-coordinated.

[0180] In some embodiments, the doped material is selected from the group consisting of:

[0181]

[0182] like Figures 1 to 4 As shown, in some embodiments of this disclosure, the light-emitting layer 500 includes a first light-emitting layer 510 and a second light-emitting layer 520, the second light-emitting layer 520 being disposed on the side of the first light-emitting layer 510 away from the anode 100; the first light-emitting layer 510 includes a first host material, and the second light-emitting layer 520 includes a second host material; at least one of the first light-emitting layer 510 and the second light-emitting layer 520 includes an auxiliary material; at least one of the first light-emitting layer 510 and the second light-emitting layer 520 includes a dopant material.

[0183] In another embodiment of this disclosure, the light-emitting layer 500 includes a first light-emitting layer 510 and a second light-emitting layer 520, the second light-emitting layer 520 being disposed on the side of the first light-emitting layer 510 away from the anode 100; the first light-emitting layer 510 includes a first main material and a first auxiliary material, the second light-emitting layer 520 includes a second main material and a second auxiliary material; at least one of the first light-emitting layer 510 and the second light-emitting layer 520 includes a doped material.

[0184] 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.

[0185] The organic light-emitting devices provided in this disclosure will be described in detail below, based on specific experimental data and other information.

[0186] Example 1

[0187] Single-layer films of compounds A1-2 and A2-7 were deposited separately using a vapor deposition process, as well as a mixed film of compounds A1-2 and A2-7 deposited by vapor deposition in a molar ratio of 1:1. The absorption and emission spectra are as follows: Figure 6 As shown, in Figure 6 In the study, the emission spectrum of the mixed film showed a red shift, which was significantly different from that of the single-layer film, indicating that compounds A1-2 and A2-7 formed the first composite transport material.

[0188] Example 2:

[0189] Using a vapor deposition process, a single-layer film of compound B-3 and a mixed film of compound B-3 and compound A2-7 were deposited separately. Their absorption and emission spectra are as follows: Figure 7 As shown, the emission spectrum of the mixed film exhibits a red shift, indicating that compounds B-3 and A2-7 form a second composite transport material.

[0190] Example 3:

[0191] Using a vapor deposition process, a single-layer film of compound B-5 and a mixed film of compound B-5 and compound A2-7 were deposited separately. Their emission spectra are as follows: Figure 8 As shown, compounds B-5 and A2-7 can also form a second composite transport material.

[0192] The energy levels of compounds A1-2, A2-7, B-3, and B-5 from the above embodiments, as well as the resulting composite transport material, were tested respectively. The results are shown in Table 1.

[0193] Table 1

[0194] Material HOMO(eV) LUMO(eV) S1(eV) T1(eV) A1-2 5.83 2.46 3.41 3.02 A2-7 6.45 3.22 3.60 2.95 B-3 5.65 3.10 2.52 2.51 B-5 5.78 3.18 2.61 2.60 A1-2:A2-7 2.69 2.67 B-3:A2-7 2.44 2.41 B-5:A2-7 2.35 2.32

[0195] To verify the performance of the organic light-emitting device provided in this application, the corresponding organic light-emitting device was fabricated and its performance was tested.

[0196] Example 3

[0197] An anode is formed on a glass substrate. The anode may include an indium tin oxide film. The anode can be formed by vacuum evaporation. Subsequently, a hole injection layer is deposited on the anode, a hole transport layer is formed on the hole injection layer, and a first exciton blocking layer is formed on the hole transport layer.

[0198] Subsequently, a first light-emitting layer was formed by co-deposition of A1-2:B-3 (70%:30%), and a second light-emitting layer was formed by co-deposition of A2-7:B-3:C-5 (64%:35%:1%).

[0199] Then, a second exciton blocking layer, an electron transport layer, an electron injection layer, and a cathode are sequentially deposited by vapor deposition. The cathode may include silver.

[0200] Example 4

[0201] A1-2:B-3 (70%:30%) was co-deposited to form the first light-emitting layer, and A2-7:B-5:C-5 (59%:40%:1%) was co-deposited to form the second light-emitting layer. The rest was the same as in Example 3.

[0202] Comparative Example 1

[0203] A light-emitting layer is formed by co-evaporation of A1-2:B-3:C-5 (59%:40%:1%), and the rest is the same as in Example 3.

[0204] Comparative Example 2

[0205] A light-emitting layer is formed by co-evaporation of A2-7:B-3:C-5 (59%:40%:1%), and the rest is the same as in Example 3.

[0206] Comparative Example 3

[0207] A first light-emitting layer is formed by co-evaporating A1-2:B-3 (70%:30%), and a second light-emitting layer is formed by co-evaporating A1-2:B-5:C-5 (59%:40%:1%). The rest is the same as in Example 3.

[0208] The performance test structure of the organic light-emitting device prepared above is shown in Table 2;

[0209] Table 2

[0210]

[0211] In Table 2, voltage, efficiency, and lifetime are percentages of other comparative examples or embodiments compared to Comparative Example 1, with Comparative Example 1 as the baseline.

[0212] Compared to Comparative Examples 1 to 3, Examples 3 and 4 show improved efficiency and lifetime. This may be because in Examples 3 and 4, A1-2 and A2-7 form the first composite transport material, and B-3 and A2-7 form the second composite transport material. Excitons can be formed on the composite transport materials and their energy can be transferred, which greatly suppresses the nonradiative transition of triplet excitons, reduces the degradation of materials caused by triplet quenching, improves material stability, and transfers energy to the next energy transport channel or to the doped material through Forster energy transfer, resulting in radiative transition luminescence, reducing energy loss and thus improving device efficiency.

[0213] Compared to Example 3, Example 4 shows a further improvement in lifetime. This is due to the addition of a second sub-composite transport material formed by A2-7 and B-5, which results in a more dispersed overall exciton energy within the device, thus mitigating material degradation to some extent.

[0214] 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, The system includes an anode, a cathode, and a light-emitting layer, wherein the light-emitting layer is disposed between the anode and the cathode; the light-emitting layer includes a first light-emitting layer and a second light-emitting layer disposed adjacent to each other, the second light-emitting layer being disposed on the side of the first light-emitting layer away from the anode; the first light-emitting layer comprises a first host material, and the second light-emitting layer comprises a second host material; at least one of the first light-emitting layer and the second light-emitting layer comprises an auxiliary material; at least one of the first light-emitting layer and the second light-emitting layer comprises a dopant material; the first host material and the second host material form a first composite transport material; and the auxiliary material and the second host material form a second composite transport material. The first host material, the second host material, the first composite transport material, the second composite transport material, and the doped material satisfy the following conditions: S1(A)>S1(CH)>S1(C); T1(A)>T1(CH)>T1(C); Wherein, S1(A) is the lowest singlet energy of the first host material or the second host material, S1(CH) is the lowest singlet energy of the first composite transport material or the second composite transport material, and S1(C) is the lowest singlet energy of the doped material. T1(A) is the lowest triplet energy of the first host material or the second host material, T1(CH) is the lowest triplet energy of the first composite transport material or the second composite transport material, and T1(C) is the lowest triplet energy of the doped material.

2. The organic light-emitting device according to claim 1, characterized in that, The first main material, the second main material, the first composite transport material, the second composite transport material, and the auxiliary material satisfy the following conditions: S1(A)>S1(CH1)>S1(CH2), S1(A)>S1(B)>S1(CH2); T1(A)>T1(CH1)>T1(CH2), T1(A)>T1(B)>T1(CH2); Wherein, S1(CH1) is the lowest singlet energy of the first composite transport material; S1(CH2) is the lowest singlet energy of the second composite transport material; S1(B) is the lowest triplet energy of the auxiliary material; T1(B) is the lowest triplet energy of the auxiliary material; T1(CH1) is the lowest triplet energy of the first composite transport material; T1(CH2) is the lowest triplet energy of the second composite transport material.

3. The organic light-emitting device according to claim 1, characterized in that, The first main material, the second main material, and the auxiliary material satisfy the following: |HOMO(A2)-LUMO(A1)| ≥ 3.5 eV, |HOMO(A1)- LUMO(A2)|≤ 3 eV, |HOMO(B)-LUMO(A2)| ≥2.3eV; Wherein, HOMO(A1) is the highest occupied molecular orbital HOMO energy level of the first host material, and LUMO(A1) is the lowest unoccupied molecular orbital LUMO energy level of the first host material. HOMO(A2) is the highest occupied molecular orbital HOMO energy level of the second host material, and LUMO(A2) is the lowest unoccupied molecular orbital LUMO energy level of the second host material; HOMO(B) is the highest occupied molecular orbital HOMO energy level of the auxiliary material, and LUMO(B) is the lowest unoccupied molecular orbital LUMO energy level of the auxiliary material.

4. The organic light-emitting device according to claim 3, characterized in that, The first main material, the second main material, and the auxiliary material satisfy the following: | HOMO(A1) |>| HOMO(B) | ≥ 5.6eV; | LUMO(B) |>| LUMO(A2) |≥1eV.

5. The organic light-emitting device according to claim 1, characterized in that, The first main material and the auxiliary material are hole-type materials, and the second main material is an electronic-type material; The hole migration rate of the first main material is higher than that of the auxiliary material.

6. The organic light-emitting device according to claim 5, characterized in that, The difference between the hole mobility and electron mobility of the auxiliary material does not exceed two orders of magnitude.

7. The organic light-emitting device according to claim 1, characterized in that, The first composite transmission material and the second composite transmission material satisfy the following: ΔE ST (CH)≤0.3 eV; Where, ΔE ST (CH) is the energy level difference between the lowest singlet energy and the lowest triplet energy of the first composite transport material, or the energy level difference between the lowest singlet energy and the lowest triplet energy of the second composite transport material.

8. The organic light-emitting device according to claim 1, characterized in that, The auxiliary material is a delayed fluorescence material, and the auxiliary material satisfies the following conditions: ΔE ST (B)≤0.3 eV; Where, ΔE ST (B) is the energy difference between the lowest singlet energy and the lowest triplet energy of the auxiliary material.

9. The organic light-emitting device according to claim 1, characterized in that, The emission spectrum of the second composite transport material overlaps with the absorption spectrum of the doped material, and the ratio of the overlapping area to the area of ​​the emission spectrum of the second composite transport material is a, where a ≥ 30%. The emission spectrum of the auxiliary material overlaps with the absorption spectrum of the doped material, and the ratio of the overlapping area to the area of ​​the emission spectrum of the auxiliary material is b, where b ≥ 30%.

10. The organic light-emitting device according to claim 1, characterized in that, The auxiliary materials include a first auxiliary material and a second auxiliary material; The second composite transmission material includes a first sub-composite transmission material and a second sub-composite transmission material; The first auxiliary material and the second main material form the first sub-composite transport material, and the second auxiliary material and the second main material form the second sub-composite transport material; The second auxiliary material and the second sub-composite transport material satisfy the following requirements: S1(B2)>S1(CH22); T1(B2)>T1(CH22); Wherein, S1(B2) is the lowest triplet energy of the second auxiliary material; T1(B2) is the lowest triplet energy of the second auxiliary material; S1(CH22) is the lowest triplet energy of the second sub-composite transport material; T1(CH22) is the lowest triplet energy of the second sub-composite transport material.

11. The organic light-emitting device according to claim 10, characterized in that, The first composite transmission material, the first auxiliary material, the second auxiliary material, the first sub-composite transmission material, and the second sub-composite transmission material satisfy the following: S1(CH1)>S1(B2)>S1(B1)>S1(CH21)>S1(CH22); T1(CH1)>T1(B2)>T1(B1)>T1(CH21)>T1(CH22); Wherein, S1(CH1) is the lowest singlet energy of the first composite transport material; S1(CH2) is the lowest singlet energy of the second composite transport material; S1(B1) is the lowest triplet energy of the second auxiliary material; T1(B1) is the lowest triplet energy of the second auxiliary material; S1(CH21) is the lowest triplet energy of the first sub-composite transport material; T1(CH21) is the lowest triplet energy of the first sub-composite transport material.

12. The organic light-emitting device according to claim 10, characterized in that, The first auxiliary material and the second auxiliary material satisfy the following: | HOMO(B2) |-| HOMO(B1) | ≤0.5eV; Wherein, HOMO(B1) is the highest occupied molecular orbital HOMO energy level of the first auxiliary material, and HOMO(B2) is the highest occupied molecular orbital HOMO energy level of the second auxiliary material.

13. The organic light-emitting device according to claim 1, characterized in that, The doping material is selected from fluorescent materials containing boron and nitrogen.

14. The organic light-emitting device according to claim 1, characterized in that, The first host material is selected from hole-type materials containing one or more groups selected from carbazole group, spirofluorene group, biphenyl group, and acridine group.

15. The organic light-emitting device according to claim 1, characterized in that, The second host material is selected from electronic materials containing one or more of the following groups: cyano group, pyridine group, pyrimidine group, triazine group, and phosphoro group.

16. The organic light-emitting device according to claim 5, characterized in that, The auxiliary material is selected from materials containing electron-donating and electron-withdrawing groups. The electron-donating group is selected from one or more of carbazole group, phenoxazine group, acridine group, fluorene group, dibenzothiophene group, and dibenzofuran group. The electron-withdrawing group is selected from one or more of cyano group, triazine group, and phosphoro group.

17. The organic light-emitting device according to claim 1, characterized in that, The first light-emitting layer comprises the first main material and the first auxiliary material, and the second light-emitting layer comprises the second main material and the second auxiliary material.

18. A display device, characterized in that, Including the organic light-emitting device as described in any one of claims 1-17.

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