Organic electroluminescent diode and method of manufacturing the same

Abstract

The application relates to an organic electroluminescence diode and a manufacturing method thereof. The light-emitting layer of the organic electroluminescence diode contains a P-type host material, an N-type host material and a guest material. The N-type host material has multiple types, and the multiple types of N-type host materials can respectively form multiple types of exciplexes with the P-type host material. The LUMO energy level of an exciplex 1 formed by the N-type host material with a relatively high LUMO energy level and the P-type host material is higher than that of an exciplex 2 formed by the N-type host material with a relatively low LUMO energy level and the P-type host material. Through the arrangement, the energy of the exciplex 1 is transferred to the guest material, and part of the energy is also transferred to the exciplex 2. The energy of the exciplex 2 is also transferred to the guest material. Thus, the energy loss can be reduced, the energy transfer can be more balanced, and the device life is improved.

Description

Technical Field

[0001] This invention relates to the field of light-emitting device technology, and in particular to an organic electroluminescent diode and its fabrication method. Background Technology

[0002] Organic light-emitting diodes (OLEDs) are widely used in the display and lighting fields due to their advantages such as wide color gamut, high color saturation and contrast, and active light emission.

[0003] The typical OLED device currently uses a sandwich structure, specifically a stacked structure with a transport layer and an emissive layer placed between the anode layer and the cathode layer. When a certain voltage is applied to the two electrodes of the OLED, holes drift from the anode and injection layer through the transport layer to the emissive layer, while electrons drift from the cathode and injection layer through the transport layer to the emissive layer. Holes and electrons recombine in the emissive layer to generate excitons, and the excitons undergo energy transitions to produce photons, thereby emitting light of a certain wavelength.

[0004] Currently, green OLEDs utilize excimer composites as the primary material. This offers the advantage of eliminating energy barriers between the charge transport layer and the emissive layer, resulting in efficient energy transfer between the excimer composite and the dopant. The formation of the excimer composite effectively reduces the polaron density and traps in the dopant, thereby lowering the likelihood of triplet quenching and leading to a small efficiency roll-off. However, the poor triplet energy confinement can cause degradation of the primary material, reducing device lifetime. Summary of the Invention

[0005] Therefore, it is necessary to provide an organic light-emitting diode and its fabrication method to improve device lifespan.

[0006] One object of the present invention is to provide an organic light-emitting diode, the solution of which is as follows:

[0007] An organic light-emitting diode, comprising:

[0008] A substrate, a first electrode layer, a light-emitting layer, and a second electrode layer are sequentially stacked.

[0009] The light-emitting layer contains a P-type host material, an N-type host material, and a guest material. There are multiple types of N-type host materials, and each type of N-type host material can independently form an excitocomplex with the P-type host material.

[0010] The LUMO energy level of the excitocomplex formed by the N-type host material and the P-type host material, which has a relatively high LUMO energy level, is higher than that of the excitocomplex formed by the N-type host material and the P-type host material, which has a relatively low LUMO energy level.

[0011] In one embodiment, the HOMO energy level of the P-type host material is lower than that of the N-type host material, the LUMO energy level of the P-type host material is lower than that of the N-type host material, and the HOMO and LUMO energy levels of various N-type host materials increase sequentially.

[0012] In one embodiment, the HOMO energy levels of the various N-type host materials increase sequentially by 0.2 eV to 0.5 eV, and the LUMO energy levels of the various N-type host materials increase sequentially by 0.2 eV to 0.5 eV.

[0013] In one embodiment, the P-type body material is selected from at least one of mCP, TCTA, TAPC, NPB, TmPyPB, and MADN.

[0014] In one embodiment, the N-type host material is selected from at least two of Alq3, B3PYMPM, Bphen, Balq, BCP, and TPBi.

[0015] In one embodiment, the guest material is selected from at least one of Ir(ppy)3, Ir(mppy)3, Ir(ppy)2acac, and Firpic.

[0016] In one embodiment, the mass ratio of the P-type host material to the N-type host material is 1:(0.1-9), and the mass fraction of the guest material in the light-emitting layer is 4%-12%.

[0017] In one embodiment, the light-emitting layer comprises the P-type host material, the N-type host material, and the guest material mixed together.

[0018] In one embodiment, at least one of a hole injection layer and a hole transport layer is further disposed between the first electrode layer and the light-emitting layer;

[0019] And / or at least one of an electron transport layer and an electron injection layer is further disposed between the light-emitting layer and the second electrode layer.

[0020] One objective of this invention is to provide a method for manufacturing an organic light-emitting diode, as follows:

[0021] A method for fabricating an organic light-emitting diode includes the following steps:

[0022] A substrate having a first electrode layer is provided;

[0023] A light-emitting layer is fabricated on the first electrode layer. The light-emitting layer contains a P-type host material, an N-type host material, and a guest material. There are multiple types of N-type host materials. The HOMO and LUMO energy levels of the multiple N-type host materials increase sequentially. The multiple N-type host materials can form corresponding multiple excitocomplexes with the P-type host material. The LUMO energy level of the excitocomplex formed by the N-type host material and the P-type host material with a relatively high LUMO energy level is higher than the LUMO energy level of the excitocomplex formed by the N-type host material and the P-type host material with a relatively low LUMO energy level.

[0024] A second electrode layer is fabricated on the light-emitting layer.

[0025] In one embodiment, the HOMO level of the P-type host material is lower than the HOMO level of the N-type host material, and the LUMO level of the P-type host material is lower than the LUMO level of the N-type host material.

[0026] Compared with traditional methods, the above-mentioned organic light-emitting diodes and their fabrication methods have the following advantages:

[0027] The aforementioned organic light-emitting diode and its fabrication method incorporate multiple N-type host materials in the light-emitting layer, which can respectively form various excimer complexes with P-type host materials. The energy of the excimer complexes can be transferred to the guest material. Furthermore, the LUMO level of excimer complex 1 formed by the N-type host material and the P-type host material, which has a relatively high LUMO level, is higher than that of excimer complex 2 formed by the N-type host material and the P-type host material, which has a relatively low LUMO level. Through this arrangement, while the energy of excimer complex 1 is transferred to the guest material, some energy is also transferred to excimer complex 2, and the energy of excimer complex 2 is also transferred to the guest material. This reduces energy loss and creates a more balanced energy transfer, which is beneficial for improving device lifespan.

[0028] The HOMO and LUMO energy levels of various N-type host materials increase sequentially and are all higher than those of the P-type host materials. This energy level configuration allows the N-type host material with higher HOMO and LUMO levels to form excitocomplex 1 with the P-type host material. While transferring energy to the guest material, some energy is also transferred to excitocomplex 2 formed by the N-type and P-type host materials with lower HOMO and LUMO levels. Excitocomplex 2 also transfers energy to the guest material. This reduces energy loss and creates a more balanced energy transfer, which is beneficial for improving device lifetime. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of an organic light-emitting diode according to an embodiment;

[0030] Figure 2 This is an energy level diagram of a traditional organic light-emitting diode (OLED) with P-type and N-type host materials in its light-emitting layer.

[0031] Figure 3 for Figure 2 Schematic diagram of energy transfer in the middle luminescent layer;

[0032] Figure 4 An energy level relationship diagram of an organic light-emitting diode with P-type host material and N-type host material in the light-emitting layer of an embodiment of the present invention;

[0033] Figure 5 for Figure 4 Schematic diagram of energy transfer in the middle luminescent layer;

[0034] Figure 6 LT95 lifetime curves of organic light-emitting diodes fabricated for Example 1 and Comparative Example 1, where curve A represents Comparative Example 1 and curve B represents Example 1;

[0035] Figure 7 The LT95 lifetime curves of the organic light-emitting diodes fabricated for Example 2 and Comparative Example 2 are shown, where curve A represents Comparative Example 2 and curve B represents Example 2.

[0036] Explanation of reference numerals in the attached figures:

[0037] 100 Organic light-emitting diode; 110 Substrate; 120 First electrode layer; 130 Light-emitting layer; 140 Second electrode layer; 150 Hole injection layer; 160 Hole transport layer; 170 Electron transport layer; 180 Electron injection layer; 190 Light extraction layer. Detailed Implementation

[0038] To facilitate understanding of the present invention, a more comprehensive description will be given below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0039] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0040] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0042] Please refer to Figure 1 As shown, an organic light-emitting diode 100 according to an embodiment of the present invention includes a substrate 110, a first electrode layer 120, a light-emitting layer 130 and a second electrode layer 140 stacked sequentially.

[0043] The luminescent layer 130 contains a p-type host material, an n-type host material, and a dopant material. There are various types of n-type host materials. Among these, the LUMO energy level of the excitocomplex formed by the n-type host material and the p-type host material, which has a relatively high LUMO energy level, is higher than the LUMO energy level of the excitocomplex formed by the n-type host material and the p-type host material, which has a relatively low LUMO energy level.

[0044] The light-emitting layer 130 of the aforementioned organic light-emitting diode 100 contains a variety of N-type host materials, which can form various excimer complexes with P-type host materials respectively. The energy of the excimer complexes can be transferred to the guest material. Furthermore, the LUMO energy level of excimer complex 1 formed by the N-type host material and the P-type host material, which has a relatively high LUMO energy level, is higher than that of excimer complex 2 formed by the N-type host material and the P-type host material, which has a relatively low LUMO energy level. With this configuration, while the energy of excimer complex 1 is transferred to the guest material, some energy is also transferred to excimer complex 2, and the energy of excimer complex 2 is also transferred to the guest material. This reduces energy loss and forms a more balanced energy transfer, which is beneficial to improving device lifespan.

[0045] In one example, various N-type host materials can form corresponding excitocomplexes with P-type host materials. The HOMO energy level of the P-type host material is lower than that of the N-type host material, and the LUMO energy level of the P-type host material is lower than that of the N-type host material. The HOMO and LUMO energy levels of the various N-type host materials increase sequentially.

[0046] In this energy level configuration, the N-type host material with higher HOMO and LUMO energy levels forms an excitocomplex 1 with the P-type host material. While transferring energy to the guest material, some energy is also transferred to the excitocomplex 2 formed by the N-type host material with lower HOMO and LUMO energy levels and the P-type host material. The energy of excitocomplex 2 is also transferred to the guest material. This reduces energy loss and creates a more balanced energy transfer, which is beneficial for improving device lifetime.

[0047] For example, in an example organic light-emitting diode 100, the light-emitting layer 130 contains a P-type host material, two N-type host materials (n-host1 and n-host2), and a guest material. The p-host can form excitocomplex 1 with n-host1, and the p-host can form excitocomplex 2 with n-host2. The energy level relationship between the P-type and N-type host materials in the light-emitting layer of a conventional organic light-emitting diode is as follows: Figure 2 As shown, energy transfer is as follows Figure 3 As shown. The energy level structure of p-host, n-host1, and n-host2 in this example is as follows: Figure 4 As shown, energy transfer is as follows Figure 4 As shown in the example, the HOMO energy levels of p-host, n-host1, and n-host2 increase sequentially, as do the LUMO energy levels of p-host, n-host1, and n-host2. Thus, while the energy of excitocomplex 1 formed by p-host and n-host1 is transferred to the guest material, a portion of the energy is also transferred to excitocomplex 2 formed by p-host and n-host2, and then transferred to the guest material. This simultaneous transfer of two portions of energy to the guest material reduces energy loss, and the more balanced energy transfer improves device lifetime.

[0048] For example, in another example of an organic light-emitting diode 100, the light-emitting layer 130 contains a p-type host material, three n-type host materials (n-host1, n-host2, and n-host3), and a guest material. The p-host can form excitocomplex 1 with n-host1, excitocomplex 2 with n-host2, and excitocomplex 3 with n-host3. The HOMO energy levels of p-host, n-host1, n-host2, and n-host3 increase sequentially, as do the LUMO energy levels of p-host, n-host1, n-host2, and n-host3. In this way, while the energy of the excitocomplex 1 formed by p-host and n-host1 is transferred to the guest material, a portion of the energy is also transferred to the excitocomplex 2 formed by p-host and n-host2 and the excitocomplex 3 formed by p-host and n-host3. A portion of the energy of excitocomplex 2 is transferred to excitocomplex 3. Thus, multiple portions of energy are transferred to the guest material at the same time, reducing energy loss. Furthermore, a more balanced energy transfer can improve the lifespan of the device.

[0049] Similarly, more types of N-type host materials (n-host) can be set in the light-emitting layer 130 to form multiple excitocomplexes with P-type host materials (p-host) for energy transfer.

[0050] In one example, the P-type host material is selected from at least one of mCP (9,9'-(1,3-phenyl)bis-9H-carbazole), CBP (4,4'-bis(9-carbazole)biphenyl), TCTA (4,4',4”-tris(carbazole-9-yl)triphenylamine), TAPC (4-[1-[4-[bis(4-methylphenyl)amino]phenyl]cyclohexyl]-N-(3-methylphenyl)-N-(4-methylphenyl)aniline), NPB (N-[1,1'-biphenyl]-4-yl-dibenzothiophene-4-amine), TmPyPB (1,3,5-tris[(3-pyridyl)-3-phenyl]benzene), and MADN (2-methyl-9,10-bis(2-naphthyl)anthracene).

[0051] In one example, the N-type host material is selected from at least two of Alq3 (aluminum 8-hydroxyquinoline), B3PYMPM (4,6-bis(3,5-di(3-pyridinylphenyl)-2-methylpyrimidine), Bphen (4,7-diphenyl-1,10-phenanthroline), Balq (bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum), BCP (2,9-dimethyl-4,7-biphenyl-1,10-o-diazaphenanthroline), and TPBi (1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene).

[0052] In one example, the guest material is selected from at least one of Ir(ppy)3 (tris(2-phenylpyridine)iridium(III)), Ir(mppy)3 (tris[2-(p-tolyl)pyridine]iridium(III)), Ir(ppy)2acac (bis(2-phenylpyridine-C2,N)iridium(III)) and Firpic (bis(4,6-difluorophenylpyridine-N,C2)pyridinecarboxyiridium).

[0053] In a specific example, in the luminescent layer 130, the P-type host material is mCP, the N-type host materials are Bphen and B3PYMPM, and the guest material is Ir(mppy)3.

[0054] In one example, the mass ratio of the P-type main material to the N-type main material is 1:(0.1 to 9). Specific examples include 1:9, 2:9, 3:9, 4:9, 5:9, 6:9, 7:9, 8:9, 1:1, 9:1, 9:2, 9:3, 9:4, 9:5, 9:6, 9:7, 9:8, etc.

[0055] In one example, the mass fraction of the guest material in the luminescent layer is 4% to 12%, specifically, for example, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, etc.

[0056] In one example, the HOMO energy levels of various N-type host materials increase sequentially by 0.2 eV to 0.5 eV, and the LUMO energy levels of various N-type host materials increase sequentially by 0.2 eV to 0.5 eV.

[0057] In one example, for a single N-type host material, the HOMO level is approximately -6.0 eV and the LUMO level is approximately -3.5 eV.

[0058] It can be understood that one of the first electrode layer 120 and the second electrode layer 140 is the anode layer, and the other is the cathode layer. The anode layer can be ITO, IZO, FTO, or a stacked structure such as ITO / Ag / ITO. The cathode layer can be Al, Ag, Au, Mg-Ag, etc.

[0059] like Figure 1 In one example, the organic light-emitting diode includes a light extraction layer 190 disposed on the side of the second electrode layer away from the light-emitting layer. The light extraction layer 190 can improve the light extraction efficiency of the device, and the material can be a high-refractive-index organic material, such as NPB.

[0060] In one example, a carrier functional layer is further provided between the first electrode layer 120 and the light-emitting layer 130 and / or between the light-emitting layer 130 and the second electrode layer 140.

[0061] In one example, the carrier functional layer is at least one of a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer.

[0062] Specifically, the first electrode layer 120 is a cathode layer, the second electrode layer 140 is an anode layer, and at least one of an electron transport layer and an electron injection layer is disposed between the first electrode layer 120 and the light-emitting layer 130; and at least one of a hole transport layer and a hole injection layer is disposed between the second electrode layer 140 and the light-emitting layer 130. Alternatively, the first electrode layer 120 is an anode layer, the second electrode layer 140 is a cathode layer, and at least one of a hole transport layer and a hole injection layer is disposed between the first electrode layer 120 and the light-emitting layer 130; and at least one of an electron transport layer and an electron injection layer is disposed between the second electrode layer 140 and the light-emitting layer 130.

[0063] exist Figure 1 In the specific example shown, the organic light-emitting diode 100 includes a substrate 110, a first electrode layer 120 (anode layer), a hole injection layer 150, a hole transport layer 160, a light-emitting layer 130, an electron transport layer 170, an electron injection layer 180, a second electrode layer 140 (cathode layer), and a light extraction layer 190, which are stacked in sequence.

[0064] The hole injection layer can be made of conductive polymers, such as PEDOT:PSS; or it can be an n-type semiconductor with a high work function, such as HAT-CN (2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene), MoO3, WO3, V2O5, Rb2O, etc.

[0065] The hole transport layer can be made of inorganic semiconductors, such as NiO and Cu2O; or organic semiconductors, such as NPB, TCTA, poly-TPD (poly[bis(4-phenyl)(4-butylphenyl)amine]), 3TPYMB (tris[2,4,6-trimethyl-3-(3-pyridyl)phenyl]borane), TFB (1,2,4,5-tetra(trifluoromethyl)benzene), TAPC, CBP (4,4'-bis(9-carbazole)biphenyl), etc.

[0066] Electron transport materials can be organic semiconductors, such as TPBi, TmPyPB, Bphen, DPPyA (9,10-bis(3-(3-pyridine)phenyl)anthracene), B3PYMPM, etc.

[0067] Electron injection materials can be alkali metal salts, such as LiF, NaF, CsF, Cs2CO3, etc.; or they can be low work function metals, such as Yb, Ca, etc.

[0068] Furthermore, the present invention also provides a method for manufacturing an organic light-emitting diode, comprising the following steps:

[0069] Step S1: Provide a substrate having a first electrode layer.

[0070] Step S2: A light-emitting layer is fabricated on the first electrode layer. The light-emitting layer contains a P-type host material, an N-type host material, and a guest material. There are multiple types of N-type host materials. These multiple N-type host materials can form corresponding excitocomplexes with the P-type host material. The LUMO energy level of the excitocomplex formed by the N-type host material and the P-type host material, which has a relatively high LUMO energy level, is higher than the LUMO energy level of the excitocomplex formed by the N-type host material and the P-type host material, which has a relatively low LUMO energy level.

[0071] Step S3: Fabricate a second electrode layer on the light-emitting layer.

[0072] The above-described method for fabricating organic light-emitting diodes (OLEDs) incorporates multiple N-type host materials in the light-emitting layer. These materials can form various excimer complexes with P-type host materials. The energy of these excimer complexes can be transferred to the guest material. Furthermore, the LUMO level of excimer complex 1, formed by the N-type host material and the P-type host material (which has a relatively high LUMO level), is higher than that of excimer complex 2, formed by the N-type host material and the P-type host material (which has a relatively low LUMO level). This arrangement ensures that while the energy of excimer complex 1 is transferred to the guest material, some energy is also transferred to excimer complex 2, and vice versa. This reduces energy loss and creates a more balanced energy transfer, which is beneficial for improving device lifespan.

[0073] Specifically, the P-type host material, N-type host material, and guest material are mixed together. For the fabrication of the luminescent layer, a solution method can be used. This method allows for the dissolution of different host materials using specific solvents, making it easier to achieve uniform mixing of multiple materials compared to vapor deposition. Specifically, the P-type host material, N-type host material, and guest material are dissolved together in a solvent to prepare a luminescent material ink. This ink is then coated onto the first electrode layer and dried to form a film. The solvent can be, for example, one or more of toluene, o-xylene, tetrahydronaphthalene, and ester solvents.

[0074] The organic light-emitting diode of the present invention will be further described below with specific embodiments. However, the present invention is not limited to the following embodiments. It should be understood that the appended claims summarize the scope of the present invention. Under the guidance of the inventive concept, those skilled in the art should realize that certain changes made to the various embodiments of the present invention will be covered by the spirit and scope of the claims of the present invention.

[0075] Example 1

[0076] The method for fabricating an organic light-emitting diode in this embodiment includes the following steps:

[0077] (1) A transparent conductive thin film ITO is used as the anode layer with a thickness of 45nm.

[0078] (2) Deposit hole injection material PEDOT:PSS on the anode to form a hole injection layer with a thickness of 40 nm.

[0079] (3) Deposit hole transport material TCTA on the hole injection layer to form a hole transport layer with a thickness of 30 nm.

[0080] (4) A luminescent material is deposited on the hole transport layer to form a luminescent layer with a thickness of 60 nm, comprising a P-type host material, an N-type host material, and a guest material. The P-type host material (p-host) is mCP, the N-type host material (n-host1) is Bphen, the N-type host material (n-host2) is B3PYMPM, and the guest material (dopant) is Ir(mppy)3. The mass ratio of p-host to n-host is 1:1, the mass fraction of dopant is 8%, and the mass ratio of n-host1 to n-host2 is 8:2.

[0081] (5) Electron transport material B3PYMPM is deposited on the above-mentioned light-emitting layer to form an electron transport layer with a thickness of 20nm.

[0082] (6) Electron injection material LiF is deposited on the above electron transport layer to form an electron injection layer with a thickness of 1 nm.

[0083] (7) A conductive material Al is deposited on the electron injection layer as a cathode layer with a thickness of 100 nm.

[0084] Example 2

[0085] The method for fabricating an organic light-emitting diode in this embodiment includes the following steps:

[0086] (1) An ITO (7nm) / Ag (110nm) / ITO (10nm) stacked structure was used as the anode layer.

[0087] (2) Deposit hole injection material HATCN on the anode to form a hole injection layer with a thickness of 50 nm.

[0088] (3) Deposit hole transport material NPB on the hole injection layer to form a hole transport layer with a thickness of 120 nm.

[0089] (4) A luminescent material is deposited on the hole transport layer to form a luminescent layer with a thickness of 60 nm, comprising a P-type host material, an N-type host material, and a guest material. The P-type host material (p-host) is mCP, the N-type host material (n-host1) is Bphen, the N-type host material (n-host2) is B3PYMPM, and the guest material (dopant) is Ir(mppy)3. The mass ratio of p-host to n-host is 1:1, the mass fraction of dopant is 8%, and the mass ratio of n-host1 to n-host2 is 8:2.

[0090] (5) Electron transport material B3PYMPM is deposited on the above-mentioned light-emitting layer to form an electron transport layer with a thickness of 30nm.

[0091] (6) A conductive material Ag is deposited on the electron transport layer as a cathode layer with a thickness of 18 nm.

[0092] (7) An NPB layer with a thickness of 80 nm is deposited on the cathode layer.

[0093] Comparative Example 1

[0094] The fabrication method of the organic light-emitting diode in this comparative example is basically the same as that in Example 1. The difference is that in step (4), the N-type host material in the light-emitting layer is only Bphen, that is, a single N-type host material.

[0095] Comparative Example 2

[0096] The fabrication method of the organic light-emitting diode in this comparative example is basically the same as that in Example 2. The difference is that in step (4), the N-type host material in the light-emitting layer is only Bphen, that is, a single N-type host material.

[0097] The organic light-emitting diodes (OLEDs) fabricated in Examples 1-2 and Comparative Examples 1-2 were subjected to performance tests. The test results are shown in Table 1. Figure 6 and Figure 7 As shown.

[0098] Group Device efficiency CIEy Example 1 58cd / A 0.618 Example 2 109cd / A 0.732 Comparative Example 1 60cd / A 0.617 Comparative Example 2 110cd / A 0.736

[0099] Depend on Figure 6 As can be seen, the LT95 lifetime of Example 1 is improved by approximately 0.8 times compared to Comparative Example 1. Figure 7As can be seen, the LT95 lifetime of Example 2 is increased by about 1.1 times compared to Comparative Example 2.

[0100] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0101] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An organic light-emitting diode, characterized in that, include: A substrate, a first electrode layer, a light-emitting layer, and a second electrode layer are sequentially stacked. The light-emitting layer contains a P-type host material, an N-type host material, and a guest material. There are three types of N-type host materials, and each of the three N-type host materials can independently form an excitocomplex with the P-type host material. The LUMO energy level of the excitocomplex formed by the N-type host material and the P-type host material, which has a relatively high LUMO energy level, is higher than that of the excitocomplex formed by the N-type host material and the P-type host material, which has a relatively low LUMO energy level. The HOMO level of the P-type host material is lower than that of the N-type host material, and the LUMO level of the P-type host material is lower than that of the N-type host material. The HOMO and LUMO levels of the various N-type host materials increase sequentially. The HOMO level of the three N-type host materials increases sequentially by 0.2 eV to 0.5 eV, and the LUMO level of the three N-type host materials increases sequentially by 0.2 eV to 0.5 eV.

2. The organic light-emitting diode as described in claim 1, characterized in that, The P-type body material is selected from at least one of mCP, TCTA, TAPC, NPB, TmPyPB and MADN.

3. The organic light-emitting diode as described in claim 1, characterized in that, The N-type host material is selected from at least two of Alq3, B3PYMPM, Bphen, Balq, BCP and TPBi.

4. The organic light-emitting diode as described in claim 1, characterized in that, The object material is selected from at least one of Ir(ppy)3, Ir(mppy)3, Ir(ppy)2acac and Firpic.

5. The organic light-emitting diode as described in claim 1, characterized in that, The mass ratio of the P-type host material to the N-type host material is 1:(0.1~9), and the mass fraction of the guest material in the light-emitting layer is 4%~12%.

6. The organic light-emitting diode as described in claim 1, characterized in that, The light-emitting layer comprises the P-type host material, the N-type host material, and the guest material mixed together.

7. The organic light-emitting diode as described in any one of claims 1 to 6, characterized in that, At least one of a hole injection layer and a hole transport layer is further disposed between the first electrode layer and the light-emitting layer; And / or at least one of an electron transport layer and an electron injection layer is further disposed between the light-emitting layer and the second electrode layer.

8. A method for fabricating an organic light-emitting diode, characterized in that, Includes the following steps: A substrate having a first electrode layer is provided; A light-emitting layer is fabricated on the first electrode layer. The light-emitting layer contains a P-type host material, an N-type host material, and a guest material. There are three types of N-type host materials. Each of the three N-type host materials can independently form various excimer complexes with the P-type host material. The LUMO energy level of the excimer complex formed by the N-type host material and the P-type host material with a relatively high LUMO energy level is higher than the LUMO energy level of the excimer complex formed by the N-type host material and the P-type host material with a relatively low LUMO energy level. The HOMO energy level of the P-type host material is lower than the HOMO energy level of the N-type host material, and the LUMO energy level of the P-type host material is lower than the LUMO energy level of the N-type host material. The HOMO energy levels and LUMO energy levels of the various N-type host materials increase sequentially. The HOMO energy levels of the three N-type host materials increase sequentially by 0.2 eV to 0.5 eV, and the LUMO energy levels of the three N-type host materials increase sequentially by 0.2 eV to 0.5 eV. A second electrode layer is fabricated on the light-emitting layer.

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