Organic light emitting diodes and electronic devices

Abstract

The present invention relates to an organic light emitting diode and an electronic device. The organic light emitting diode comprises: an anode, a light emitting layer, an intermediate layer and a cathode which are stacked in sequence; wherein the light emitting layer comprises a main material, and the intermediate layer comprises a modifying material; the absolute value of the difference between the HOMO energy level of the modifying material and the HOMO energy level of the main material is ≤0.1 eV; the absolute value of the difference between the LUMO energy level of the modifying material and the LUMO energy level of the main material is ≤0.1 eV; the absolute value of the difference between the T1 energy level of the modifying material and the T1 energy level of the main material is ≤0.1 eV; the main material and the modifying material are different. By matching the energy levels, the exciton recombination zone is expanded, the quenching is reduced, and the device efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electroluminescence, and in particular to an organic light emitting diode and an electronic device. Background Art

[0002] After decades of development, OLED display panels are constantly occupying the small and medium-sized display market, replacing the original LCD display, and becoming a mainstream technology. Compared with LCD, OLED has a faster response speed, higher contrast, lower power consumption, and OLED has more application scenarios, such as flexibility, curling, folding, etc. Common OLEDs include a cathode, an anode, and a light-emitting layer (EML) disposed between the cathode and the anode, as well as several other organic functional layers, such as a hole injection layer (HIL), a hole transport layer (HTL), an electron injection layer (EIL), and an electron transport layer (ETL). The light-emitting layer usually contains a host material and a guest material (or dopant). In order to further improve the efficiency of the device, a hole blocking layer (HBL) is usually set between the light-emitting layer and the electron transport layer, and an electron blocking layer (EBL) is set between the light-emitting layer and the hole transport layer, so that the carriers and excitons can be confined to the light-emitting layer.

[0003] Generally speaking, the LUMO energy level of the electron blocking layer material must form a certain barrier height with the LUMO energy level of the light-emitting layer material to block electrons and excitons, and also promote the injection of holes from the adjacent hole transport layer to the electron blocking layer, and from the electron blocking layer to the adjacent light-emitting layer. Correspondingly, the HOMO energy level of the hole blocking layer material must also form a certain barrier height with the HOMO energy level of the light-emitting layer material to block holes and excitons, and also promote the injection of electrons from the adjacent electron transport layer to the hole blocking layer, and from the hole blocking layer to the adjacent light-emitting layer. In addition, the T1 (first excited triplet state) energy level of the electron blocking layer material and the hole blocking layer material is required to be greater than the T1 energy level of the light-emitting material. However, in practical applications, it is difficult to find and design such an effective hole blocking material or electron blocking material. How to improve the efficiency of organic light-emitting diodes has always troubled relevant researchers. Summary of the invention

[0004] Based on this, the present invention provides a technical solution capable of improving the efficiency of an organic light emitting diode.

[0005] The technical solution is as follows:

[0006] An organic light emitting diode, comprising:

[0007] An anode, a light-emitting layer, an intermediate layer and a cathode are stacked in sequence;

[0008] in,

[0009] The light-emitting layer comprises a host material, and the intermediate layer comprises a modifying material;

[0010] The absolute value of the difference between the HOMO energy level of the modifying material and the HOMO energy level of the host material is ≤0.1 eV;

[0011] The absolute value of the difference between the LUMO energy level of the modifying material and the LUMO energy level of the host material is ≤0.1 eV;

[0012] The absolute value of the difference between the T1 energy level of the modifying material and the T1 energy level of the host material is ≤0.1 eV;

[0013] The main body material and the modifying material are different.

[0014] The present invention also provides an electronic device, which comprises the organic light emitting diode.

[0015] The present invention has the following beneficial effects:

[0016] The organic light emitting diode provided by the present invention comprises an anode, a light emitting layer, an intermediate layer and a cathode which are stacked, wherein the light emitting layer comprises a main material, and the intermediate layer comprises a modifying material, and the two materials are different. Since the absolute value of the difference between the HOMO energy level of the modifying material and the HOMO energy level of the main material is ≤0.1eV, the absolute value of the difference between the LUMO energy level of the modifying material and the LUMO energy level of the main material is ≤0.1eV, and the absolute value of the difference between the T1 energy level of the modifying material and the T1 energy level of the main material is ≤0.1eV, the exciton recombination zone is expanded, quenching is reduced, and the device efficiency is improved through energy level matching. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram of an OLED device according to an embodiment of the present invention;

[0018] Figure 2 is a schematic structural diagram of a normal OLED device according to another embodiment of the present invention;

[0019] Figure 3 is a schematic structural diagram of an inverted OLED device according to another embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of the energy levels of the conventional blue light OLED light emitting layer and the hole blocking layer T1, and the blue light OLED light emitting layer and the intermediate layer T1 of the present invention;

[0021] Figure 5 An embodiment of the present invention is about Figure 2 The flowchart of the preparation method of the upright OLED device shown;

[0022] Figure 6An embodiment of the present invention is about Figure 3 The process flow chart of the preparation method of the inverted OLED device shown;

[0023] Figure 7 is a schematic structural diagram of a normal OLED device in Comparative Examples 1 to 3 of the present invention;

[0024] Figure 8 is a schematic structural diagram of a normal OLED device in Comparative Example 4 of the present invention;

[0025] Fig. 9 These are the test results of the luminous efficiency of the blue light OLED in Examples 1 to 3 and Comparative Example 1. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and effect of the present invention clearer and more specific, the present invention is further described in detail below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0028] When describing positional relationships, unless otherwise specified, when an element such as a layer, film, or substrate is referred to as being "on" another film layer, it can be directly on the other film layer or there can be an intermediate film layer. Further, when a layer is referred to as being "under" another layer, it can be directly below or there can be one or more intermediate layers. It is also understood that when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or there can be one or more intermediate layers.

[0029] Where “including,” “having,” and “comprising” are used herein, it is intended to cover a non-exclusive inclusion, and another component may also be added unless explicit limiting terms such as “only,” “consisting of,” etc. are used.

[0030] Unless mentioned to the contrary, terms in the singular may include plural forms and should not be construed as being one in number.

[0031] In addition, the drawings are not drawn in a 1:1 ratio, and the relative sizes of the elements are drawn in the drawings only as examples to facilitate understanding of the present invention, but are not necessarily drawn in true proportion. The proportions in the drawings do not constitute a limitation to the present invention.

[0032] The present invention provides a technical solution capable of improving the efficiency of an organic light emitting diode.

[0033] The technical solution is as follows:

[0034] See also Figure 1 , an organic light emitting diode, comprising: an anode 101, a light emitting layer 102, an intermediate layer 1003 and a cathode 104 stacked in sequence; wherein the light emitting layer comprises a main material, and the intermediate layer comprises a modifying material; the absolute value of the difference between the HOMO energy level of the modifying material and the HOMO energy level of the main material is ≤0.1eV; the absolute value of the difference between the LUMO energy level of the modifying material and the LUMO energy level of the main material is ≤0.1eV; the absolute value of the difference between the T1 energy level of the modifying material and the T1 energy level of the main material is ≤0.1eV; the main material and the modifying material are different.

[0035] The present invention expands the exciton recombination zone and reduces quenching through energy level matching, thereby improving device performance.

[0036] In one embodiment, the absolute value of the difference between the HOMO energy level of the modifying material and the HOMO energy level of the main material is ≤0.05Ev; the absolute value of the difference between the LUMO energy level of the modifying material and the LUMO energy level of the main material is ≤0.05eV; the absolute value of the difference between the T1 energy level of the modifying material and the T1 energy level of the main material is ≤0.05eV.

[0037] In one embodiment, the absolute value of the difference between the Fermi level of the modification material and the Fermi level of the host material is ≤ 0.1 eV. This ensures that the host materials of the intermediate layer and the light-emitting layer have similar semiconductor polarities.

[0038] In one embodiment, the absolute value of the difference between the Fermi level of the modifying material and the Fermi level of the host material is ≤0.05 eV.

[0039] In one embodiment, the organic light emitting diode is a blue organic light emitting diode.

[0040] In one embodiment, the main material and the modified material are independently selected from 9,10-di-2-naphthothracene (ADN, CAS: 122648-99-1), 9,10-di(2-naphthyl)-2-methylanthracene (MADN, CAS: 804560-00-7), 2-(tert-butyl)-9,10-di(naphthalene-2-yl)anthracene (TBADN, CAS: 274905-73-6), 4,4'-di[10-(naphthalene-1-yl)anthracene-9-yl]biphenyl (CAS: 1002328-32-6), 10,10'-di(biphenyl-4-yl)-9,9'-bianthracene (CAS: 172285-79-9) and 9-(naphthalene-1-yl)-10-(naphthalene-2-yl)anthracene (CAS: 855828-36-3). The chemical structure is as follows:

[0041]

[0042] The use of the above-mentioned main materials and modified materials is conducive to further improving the efficiency of the device. In addition, the above-mentioned raw materials are cheap, which is conducive to reducing costs.

[0043] In one embodiment, the main material is ADN, and the modification material is MADN.

[0044] In one embodiment, the main material is ADN, and the modified material is TBADN.

[0045] In one embodiment, the main material is ADN, and the modification material is a mixture of MADN and TBADN.

[0046] In one embodiment, the main material is ADN, and the modified material is 4,4'-di[10-(naphthalene-1-yl)anthracene-9-yl]biphenyl.

[0047] In one embodiment, the main material is ADN, and the modified material is 10,10'-di(biphenyl-4-yl)-9,9'-bianthracene.

[0048] In one embodiment, the main material is TBADN, and the modified material is 9-(naphthalene-1-yl)-10-(naphthalene-2-yl)anthracene.

[0049] In one embodiment, the main material is MADN, and the modified material is ADN.

[0050] In one embodiment, the main material is MADN, and the modification material is TBADN.

[0051] In one embodiment, the main material is TBADN, and the modified material is 4,4'-di[10-(naphthalene-1-yl)anthracene-9-yl]biphenyl.

[0052] In one embodiment, the thickness of the light-emitting layer is 20-60 nm, and the thickness of the intermediate layer is 5-15 nm. Appropriate thickness is conducive to controlling the amount of holes and electrons, and then controlling the amount of excitons, thereby achieving the purpose of improving device efficiency.

[0053] In one embodiment, the light-emitting layer further comprises a guest material, and the content of the guest material is ≤5% by weight of the light-emitting layer. The combination of the host material and the guest material is conducive to further improving the luminous efficiency of the device. Specifically, based on the total mass of the light-emitting layer, the content of the host material is ≥95wt%, and the content of the guest material is ≤5wt%. For example, based on the total mass of the light-emitting layer, the content of the host material is 95%, and the content of the guest material is 5wt%; for another example, the content of the host material is 96%, and the content of the guest material is 4wt%; for another example, the content of the host material is 97%, and the content of the guest material is 3wt%; for another example, the content of the host material is 98%, and the content of the guest material is 2wt%; for another example, the content of the host material is 99%, and the content of the guest material is 1wt%.

[0054] In one embodiment, the guest material is selected from diaromatic amine pyrene derivatives and / or boron-nitrogen heterocyclic condensed ring compounds. Both diaromatic amine pyrene derivatives and boron-nitrogen heterocyclic condensed ring compounds have excellent luminescent properties, which are beneficial for cooperating with the host material to improve the luminescent efficiency of the device.

[0055] In one embodiment, the diaromatic aminopyrene derivative is selected from J1, J2, J3, J4, J5, J6 or J7; these materials can refer to patents WO2009084512A1 and CN101068041A.

[0056]

[0057] In one embodiment, the boron-nitrogen heterocyclic condensed ring compound is selected from DABNA-1, DABNA-2, t-DABNA, TBN-TPA, B2, BBCz-DB or v-DABNA; these materials can refer to patents US20210159411A1, US20200243776A1, US20210249606A1, CN112898325A, CN112592362A, [Yang M, Park IS, Yasuda T. Full-Color, Narrowband, and High-Efficiency Electroluminescence from Boron and Carbazole Embedded Polycyclic Heteroaromatics[J]. Journal of the American Chemical Society, 2020.] and CN112331704A.

[0058]

[0059] In one embodiment, the thickness of the anode is 20 nm to 100 nm, and the thickness of the cathode is 20 nm to 200 nm.

[0060] In one embodiment, the anode material is selected from but not limited to high work function metals such as ITO, IZO, Au, and metal oxides thereof.

[0061] In one embodiment, the cathode material is at least one of a conductive carbon material, a metal material and a transparent conductive oxide material, wherein the conductive carbon material includes but is not limited to doped or undoped carbon nanotubes, doped or undoped graphene, doped or undoped graphene oxide, C60, graphite, carbon fiber, porous carbon; the metal material includes but is not limited to aluminum, silver, gold, calcium, barium, magnesium or their alloys; the transparent conductive oxide includes but is not limited to ITO, FTO, ATO, AZO, IZO, IZTO, IGTO.

[0062] In one embodiment, the organic light emitting diode further includes a hole injection layer disposed between the anode and the light emitting layer, a hole transport layer disposed between the hole injection layer and the light emitting layer, and an electron transport layer disposed between the intermediate layer and the cathode.

[0063] In the present invention, the organic light emitting diode is a positive OLED or an inverted OLED.

[0064] As one embodiment, the organic light emitting diode is a positive OLED, see Figure 2The upright OLED includes a stacked substrate 201, an anode 202, a hole injection layer 203, a hole transport layer 204, a light-emitting layer 205, an intermediate layer 206, an electron transport layer 207 and a cathode 208; the light-emitting layer 205 contains a main material, and the intermediate layer 206 contains a modifying material.

[0065] As another embodiment, the organic light emitting diode is an inverted OLED, see Figure 3 The inverted OLED includes a stacked substrate 301, a cathode 302, an electron transport layer 303, an intermediate layer 304, a light-emitting layer 305, a hole transport layer 306, a hole injection layer 307 and an anode 308; the light-emitting layer 305 includes a main material, and the intermediate layer 304 includes a modifying material.

[0066] Figure 4 It is shown that in a conventional blue OLED, a hole blocking layer is arranged between the light-emitting layer and the electron transport layer, and the T1 energy level of the hole blocking layer material is greater than the T1 energy level of the light-emitting layer material; while in the blue OLED of the present invention, the absolute value of the difference between the T1 energy level of the modified material and the T1 energy level of the main material is ≤0.1 eV, and a higher efficiency can be achieved compared with the conventional blue OLED.

[0067] In one embodiment, the materials used to prepare the hole injection layer of the upright and / or inverted OLED include but are not limited to: conductive polymers. For example: PEDOT:PSS (poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid)), PANI:PSS (polyaniline:poly(styrenesulfonic acid)). Or other organic materials, including but not limited to: one or more of 4,4',4"-tri(carbazole-9-yl)triphenylamine (TCTA) and 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone (F4TCNQ).

[0068] In one embodiment, the materials used to prepare the hole transport layer of the upright and / or inverted OLED include but are not limited to: one or more of poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine] (poly-TPD), poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(4,4'-(N-(4-n-butyl)phenyl)-diphenylamine)] (TFB), polyvinylcarbazole (PVK), 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline (TAPC), N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB) and 4,4',4"-tri(carbazole-9-yl)triphenylamine (TCTA).

[0069] In one embodiment, the materials used to prepare the electron transport layer of the upright and / or inverted OLED include but are not limited to: one or more of beryllium pyridinium (Bepp2), (8-hydroxyquinoline) lithium (Liq), ZnMgO, BAlq3, 1,3,5-tri(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi), 1,3,5-tri[(3-pyridyl)-phenol-3-yl]benzene (TmPyPb), 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline (BCP) and 4,7-diphenyl-1,10-phenanthroline (Bphen).

[0070] In one embodiment, the thickness of the hole injection layer for preparing the upright and / or inverted OLED is 10-100 nm.

[0071] In one embodiment, the thickness of the hole transport layer for preparing the upright and / or inverted OLED is 20-200 nm.

[0072] In one embodiment, the thickness of the electron transport layer for preparing the upright and / or inverted OLED is 15-100 nm.

[0073] The present invention also provides a method for preparing an organic light emitting diode, wherein the organic light emitting diode comprises an anode, a light emitting layer, an intermediate layer and a cathode which are stacked, and the method for preparing the organic light emitting diode comprises the following steps:

[0074] Prepare the light-emitting layer by vapor deposition or solution method;

[0075] Prepare the intermediate layer on the light-emitting layer by vapor deposition or solution method; or

[0076] The intermediate layer is prepared by a vapor deposition method or a solution method;

[0077] Prepare the light-emitting layer on the intermediate layer by vapor deposition or solution method;

[0078] The light-emitting layer comprises a host material, and the intermediate layer comprises a modifying material;

[0079] The absolute value of the difference between the HOMO energy level of the modifying material and the HOMO energy level of the host material is ≤0.1 eV;

[0080] The absolute value of the difference between the LUMO energy level of the modifying material and the LUMO energy level of the host material is ≤0.1 eV;

[0081] The absolute value of the difference between the T1 energy level of the modifying material and the T1 energy level of the host material is ≤0.1 eV;

[0082] The main body material and the modifying material are different.

[0083] In one embodiment, the solution method used to prepare the light-emitting layer and the intermediate layer includes inkjet printing or spin coating, and the vapor deposition method includes evaporation.

[0084] See also Figure 5 , for structures such as Figure 2 The preparation method of the upright OLED shown includes the following steps:

[0085] providing a substrate, and preparing an anode on the substrate;

[0086] preparing a hole injection layer on the anode;

[0087] preparing a hole transport layer on the hole injection layer;

[0088] preparing a light-emitting layer on the hole transport layer by a vapor deposition method or a solution method;

[0089] preparing an intermediate layer on the light-emitting layer by a vapor deposition method or a solution method;

[0090] preparing an electron transport layer on the intermediate layer;

[0091] A cathode is prepared on the electron transport layer.

[0092] See also Figure 6 , for structures such as Figure 3 The inverted OLED shown, its preparation method comprises the following steps:

[0093] providing a substrate, and preparing a cathode on the substrate;

[0094] preparing an electron transport layer on the cathode;

[0095] preparing a light-emitting layer on the electron transport layer by a vapor deposition method or a solution method;

[0096] preparing an intermediate layer on the light-emitting layer by a vapor deposition method or a solution method;

[0097] preparing an electron transport layer on the intermediate layer;

[0098] A cathode is prepared on the electron transport layer.

[0099] In one of the embodiments, the anode is prepared by magnetron sputtering or a substrate with ITO is directly purchased, and ITO is used as the anode; the hole injection layer, hole transport layer and electron transport layer in the upright and / or inverted structure OLED are prepared by a solution method or a vapor deposition method, the solution method includes inkjet printing or spin coating, and the vapor deposition method is an evaporation method; the cathode in the upright and / or inverted structure OLED is prepared by a vapor deposition method, such as an evaporation method.

[0100] The present invention also provides an electronic device, which comprises the organic light emitting diode.

[0101] In one embodiment, the electronic device is selected from but not limited to a display device, a lighting device, a light source, a sensor, and the like.

[0102] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments.

[0103] Embodiments 1 to 5 are upright OLEDs, and their structures refer to Figure 2 , including a substrate 201, an anode 202, a hole injection layer 203, a hole transport layer 204, a light emitting layer 205, an intermediate layer 206, an electron transport layer 207 and a cathode 208 which are stacked;

[0104] Example 6 is an inverted OLED, the structure of which is shown in Figure 3 , including a substrate 301, a cathode 302, an electron transport layer 303, an intermediate layer 304, a light-emitting layer 305, a hole transport layer 306, a hole injection layer 307 and an anode 308 which are stacked;

[0105] Comparative Examples 1 to 3 are upright OLEDs, and their structures are shown in Figure 7 , including a substrate 701, an anode 702, a hole injection layer 703, a hole transport layer 704, a light-emitting layer 705, an electron transport layer 706 and a cathode 707 which are stacked.

[0106] Comparative Example 4 is a normal OLED, and its structure is shown in Figure 8 , including a stacked substrate 801, an anode 802, a hole injection layer 803, a hole transport layer 804, a light-emitting layer 805, a hole blocking layer 806, an electron transport layer / 807 and a cathode 808.

[0107] Example 1

[0108] This embodiment provides a positive OLED device and a method for preparing the same. The preparation process is as follows:

[0109] (1) providing a transparent conductive film ITO containing a glass substrate, with ITO as an anode and a thickness of 50 nm;

[0110] (2) PANI:PSS was deposited on ITO using inkjet printing method as a hole injection layer with a thickness of 30 nm;

[0111] (3) Depositing TFB as a hole transport layer on the hole injection layer by inkjet printing with a thickness of 25 nm;

[0112] (4) ADN (96 wt%):v-DABNA (4 wt%) was deposited on the hole transport layer by inkjet printing as a light-emitting layer with a thickness of 30 nm;

[0113] (5) Depositing TBADN as an intermediate layer on the light-emitting layer by evaporation with a thickness of 5 nm;

[0114] (6) Depositing Bphen:Liq (mass ratio 4:6) as an electron transport layer on the intermediate layer by evaporation method with a thickness of 30 nm;

[0115] (7) Al was deposited on the electron transport layer by evaporation as a cathode with a thickness of 100 nm.

[0116] Example 2

[0117] This embodiment provides a positive OLED device and a method for preparing the same. The preparation process is as follows:

[0118] (1) providing a transparent conductive film ITO containing a glass substrate, with ITO as an anode and a thickness of 50 nm;

[0119] (2) PANI:PSS was deposited on ITO by spin coating to a thickness of 30 nm as a hole injection layer;

[0120] (3) Depositing TFB as a hole transport layer on the hole injection layer by spin coating with a thickness of 25 nm;

[0121] (4) ADN (96 wt%): v-DABNA (4 wt%) was deposited on the hole transport layer by spin coating to form a light-emitting layer with a thickness of 30 nm;

[0122] (5) Depositing TBADN as an intermediate layer on the light-emitting layer by evaporation with a thickness of 10 nm;

[0123] (6) Depositing Bphen:Liq (mass ratio 4:6) as an electron transport layer on the intermediate layer by evaporation method with a thickness of 30 nm;

[0124] (7) Al was deposited on the electron transport layer by evaporation as a cathode with a thickness of 100 nm.

[0125] Example 3

[0126] This embodiment provides a positive OLED device and a method for preparing the same. The preparation process is as follows:

[0127] (1) providing a transparent conductive film ITO containing a glass substrate, with ITO as an anode and a thickness of 50 nm;

[0128] (2) PANI:PSS was deposited on ITO using inkjet printing method as a hole injection layer with a thickness of 30 nm;

[0129] (3) Depositing TFB as a hole transport layer on the hole injection layer by inkjet printing with a thickness of 25 nm;

[0130] (4) ADN (96 wt%):v-DABNA (4 wt%) was deposited on the hole transport layer by inkjet printing as a light-emitting layer with a thickness of 30 nm;

[0131] (5) Depositing TBADN as an intermediate layer on the light-emitting layer by evaporation with a thickness of 15 nm;

[0132] (6) Depositing Bphen:Liq (mass ratio 4:6) as an electron transport layer on the intermediate layer by evaporation method with a thickness of 30 nm;

[0133] (7) Al was deposited on the electron transport layer by evaporation as a cathode with a thickness of 100 nm.

[0134] Example 4

[0135] This embodiment provides a positive OLED device and a method for preparing the same. The preparation process is as follows:

[0136] (1) providing a transparent conductive film ITO containing a glass substrate, with ITO as an anode and a thickness of 50 nm;

[0137] (2) PANI:PSS was deposited on ITO using inkjet printing method as a hole injection layer with a thickness of 30 nm;

[0138] (3) Depositing TFB as a hole transport layer on the hole injection layer by inkjet printing with a thickness of 25 nm;

[0139] (4) ADN (96 wt%):v-DABNA (4 wt%) was deposited on the hole transport layer by inkjet printing as a light-emitting layer with a thickness of 30 nm;

[0140] (5) MADN (50 wt%):TBADN (50 wt%) was deposited on the light-emitting layer by evaporation as an intermediate layer with a thickness of 5 nm;

[0141] (6) Depositing Bphen:Liq (mass ratio 4:6) as an electron transport layer on the intermediate layer by evaporation method with a thickness of 30 nm;

[0142] (7) Al was deposited on the electron transport layer by evaporation as a cathode with a thickness of 100 nm.

[0143] Example 5

[0144] This embodiment provides a positive OLED device and a method for preparing the same. The preparation process is as follows:

[0145] (1) providing a transparent conductive film ITO containing a glass substrate, with ITO as an anode and a thickness of 50 nm;

[0146] (2) PANI:PSS was deposited on ITO using inkjet printing method as a hole injection layer with a thickness of 30 nm;

[0147] (3) Depositing TFB as a hole transport layer on the hole injection layer by inkjet printing with a thickness of 25 nm;

[0148] (4) MADN (96 wt%):DABNA-1 (4 wt%) was deposited on the hole transport layer by inkjet printing as a light-emitting layer with a thickness of 30 nm;

[0149] (5) ADN (20 wt%):TBADN (80 wt%) was deposited on the light-emitting layer by evaporation as an intermediate layer with a thickness of 5 nm;

[0150] (6) Depositing Bphen:Liq (mass ratio 4:6) as an electron transport layer on the intermediate layer by evaporation method with a thickness of 30 nm;

[0151] (7) Al was deposited on the electron transport layer by evaporation as a cathode with a thickness of 100 nm.

[0152] Example 6

[0153] This embodiment provides a positive OLED device and a method for preparing the same. The preparation process is as follows:

[0154] (1) A transparent conductive film ITO containing a glass substrate is provided, with ITO as the cathode and a thickness of 50 nm.

[0155] (2) ZnMgO was deposited on ITO by solution method as an electron transport layer with a thickness of 40 nm;

[0156] (3) ADN was deposited on the electron transport layer by evaporation method as an intermediate layer with a thickness of 10 nm;

[0157] (4) MADN (96 wt%):DABNA-1 (4 wt%) was deposited on the intermediate layer by evaporation as a light-emitting layer with a thickness of 30 nm;

[0158] (5) TCTA was deposited on the light-emitting layer by evaporation as a hole transport layer with a thickness of 40 nm;

[0159] (6) TCTA:F4TCNQ (95wt%:5wt%) was deposited on the hole transport layer by evaporation method as a hole injection layer with a thickness of 10 nm;

[0160] (7) Al was deposited on the hole injection layer by evaporation to a thickness of 100 nm as an anode.

[0161] Comparative Example 1

[0162] This comparative example provides a positive OLED device and a preparation method thereof. The preparation process is as follows:

[0163] (1) providing a transparent conductive film ITO containing a glass substrate, with ITO as an anode and a thickness of 50 nm;

[0164] (2) PANI:PSS was deposited on ITO using inkjet printing method as a hole injection layer with a thickness of 30 nm;

[0165] (3) Depositing TFB as a hole transport layer on the hole injection layer by inkjet printing with a thickness of 25 nm;

[0166] (4) ADN (96 wt%):v-DABNA (4 wt%) was deposited on the hole transport layer by inkjet printing as a light-emitting layer with a thickness of 30 nm;

[0167] (5) Depositing Bphen:Liq (mass ratio 4:6) as an electron transport layer on the light-emitting layer by evaporation with a thickness of 30 nm;

[0168] (6) Al was deposited on the electron transport layer by evaporation as a cathode with a thickness of 100 nm.

[0169] Comparative Example 2

[0170] This comparative example provides a positive OLED device and a preparation method thereof. The preparation process is as follows:

[0171] (1) providing a transparent conductive film ITO containing a glass substrate, with ITO as an anode and a thickness of 50 nm;

[0172] (2) PANI:PSS was deposited on ITO using inkjet printing method as a hole injection layer with a thickness of 30 nm;

[0173] (3) Depositing TFB as a hole transport layer on the hole injection layer by inkjet printing with a thickness of 25 nm;

[0174] (4) ADN (96 wt%): v-DABNA (4 wt%) was deposited on the hole transport layer by inkjet printing as a light-emitting layer with a thickness of 35 nm;

[0175] (5) Depositing Bphen:Liq (mass ratio 4:6) as an electron transport layer on the light-emitting layer by evaporation with a thickness of 30 nm;

[0176] (6) Al was deposited on the electron transport layer by evaporation as a cathode with a thickness of 100 nm.

[0177] Comparative Example 3

[0178] This comparative example provides a positive OLED device and a preparation method thereof. The preparation process is as follows:

[0179] (1) providing a transparent conductive film ITO containing a glass substrate, with ITO as an anode and a thickness of 50 nm;

[0180] (2) PANI:PSS was deposited on ITO using inkjet printing method as a hole injection layer with a thickness of 30 nm;

[0181] (3) Depositing TFB as a hole transport layer on the hole injection layer by inkjet printing with a thickness of 25 nm;

[0182] (4) TBADN (96 wt%):v-DABNA (4 wt%) was deposited on the hole transport layer by inkjet printing as a light-emitting layer with a thickness of 35 nm;

[0183] (5) Depositing Bphen:Liq (mass ratio 4:6) as an electron transport layer on the light-emitting layer by evaporation with a thickness of 30 nm;

[0184] (6) Al was deposited on the electron transport layer by evaporation as a cathode with a thickness of 100 nm.

[0185] Comparative Example 4

[0186] This comparative example provides a positive OLED device and a preparation method thereof. The preparation process is as follows:

[0187] (1) providing a transparent conductive film ITO containing a glass substrate, with ITO as an anode and a thickness of 50 nm;

[0188] (2) PANI:PSS was deposited on ITO using inkjet printing method as a hole injection layer with a thickness of 30 nm;

[0189] (3) Depositing TFB as a hole transport layer on the hole injection layer by inkjet printing with a thickness of 25 nm;

[0190] (4) ADN (96 wt%):v-DABNA (4 wt%) was deposited on the hole transport layer by inkjet printing as a light-emitting layer with a thickness of 30 nm;

[0191] (5) Depositing TmPyPb as a hole blocking layer on the light-emitting layer by evaporation method with a thickness of 5 nm;

[0192] (6) Depositing Bphen:Liq (mass ratio 4:6) as an electron transport layer on the hole blocking layer by evaporation method with a thickness of 30 nm;

[0193] (7) Al was deposited on the electron transport layer by evaporation as a cathode with a thickness of 100 nm.

[0194] test

[0195] The performance tests were performed on the blue light OLEDs in Examples 1 to 6 and Comparative Examples 1 to 4:

[0196] Test method: Use a dedicated IVL test system to test the device's electrical, optical and other parameters.

[0197] The test results are shown in Table 1 and Fig. 9 As shown:

[0198] Table 1

[0199]

[0200]

[0201] As can be seen from Table 1, compared with Comparative Examples 1 to 4, the EQE of the OLEDs in Examples 1 to 6 are all improved to varying degrees, among which the EQE of Example 2 is the highest and the improvement is most obvious. It can be seen that the present invention can increase the luminous efficiency of the device by matching the energy levels, expanding the exciton recombination zone, and reducing quenching.

[0202] from Fig. 9 It can be seen that the EQE of the OLEDs in Examples 1 to 3 are improved to varying degrees compared to Comparative Example 1, among which the EQE of Example 2 is the highest and the improvement is most obvious. It can also be confirmed that the present invention can increase the luminous efficiency of the device by matching the energy levels, expanding the exciton recombination zone, and reducing quenching.

[0203] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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.

[0204] The above-described embodiments only express several implementation methods of the present invention, which are convenient for understanding the technical solutions of the present invention in detail, but they cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention, several modifications and improvements can be made, which all belong to the protection scope of the present invention. It should be understood that the technical solutions obtained by ordinary technicians in this field through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided by the present invention are all within the protection scope of the claims attached to the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the contents of the attached claims, and the description and drawings can be used to explain the contents of the claims.

Claims

1. An organic light emitting diode, It is characterized in that include: An anode, a light-emitting layer, an intermediate layer and a cathode are stacked in sequence; in, The light-emitting layer comprises a host material, and the intermediate layer comprises a modifying material; The absolute value of the difference between the HOMO energy level of the modifying material and the HOMO energy level of the host material is ≤0.1 eV; The absolute value of the difference between the LUMO energy level of the modifying material and the LUMO energy level of the host material is ≤0.1 eV; The T of the modified material 1 Energy level and T of the host material 1 The absolute value of the energy level difference is ≤0.1eV; The absolute value of the difference between the Fermi level of the modified material and the Fermi level of the host material is ≤0.1 eV; The main material and the modified material meet one of the following conditions: (1) The main material is ADN and the modified material is MADN; (2) The main material is ADN, and the modified material is a mixture of MADN and TBADN; (3) The main material is ADN, and the modified material is 4,4'-di[10-(naphthalene-1-yl)anthracene-9-yl]biphenyl; (4) The main material is ADN, and the modified material is 10,10'-di(biphenyl-4-yl)-9,9'-bianthracene; (5) The main material is TBADN, and the modified material is 9-(naphthalene-1-yl)-10-(naphthalene-2-yl)anthracene; (6) The main material is MADN, and the modifying material is AND; (7) The main material is MADN and the modified material is TBADN; (8) The main material is TBADN, and the modified material is 4,4'-di[10-(naphthalene-1-yl)anthracene-9-yl]biphenyl.

2. The organic light emitting diode according to claim 1, It is characterized in that The organic light emitting diode is a blue organic light emitting diode.

3. The organic light emitting diode according to claim 1, It is characterized in that The thickness of the light-emitting layer is 20-60 nm, and the thickness of the intermediate layer is 5-15 nm.

4. The organic light emitting diode according to claim 1, It is characterized in that The light-emitting layer further comprises a guest material, and the content of the guest material is ≤5% by weight of the light-emitting layer.

5. The organic light emitting diode according to claim 4, It is characterized in that The guest material is selected from diaromatic aminopyrene derivatives and / or boron-nitrogen-containing heterocyclic condensed ring compounds.

6. The organic light emitting diode according to claim 5, It is characterized in that The diaromatic aminopyrene derivative is selected from J1, J2, J3, J4, J5, J6 or J7; The boron-nitrogen heterocyclic condensed ring compound is selected from DABNA-1, DABNA-2, t-DABNA, TBN-TPA, B2, BBCz-DB or v-DABNA; 。 7. The organic light emitting diode according to any one of claims 1 to 6, It is characterized in that The organic light emitting diode further comprises: A hole injection layer disposed between the anode and the light-emitting layer; A hole transport layer disposed between the hole injection layer and the light emitting layer; An electron transport layer is disposed between the intermediate layer and the cathode.

8. The organic light emitting diode according to claim 7, It is characterized in that The hole injection layer comprises one or more of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid), polyaniline:poly(styrenesulfonic acid), 4,4',4''-tri(carbazole-9-yl)triphenylamine and 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone; The hole transport layer comprises one or more of poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine], poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(4,4'-(N-(4-n-butyl)phenyl)-diphenylamine)], polyvinylcarbazole, 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline, N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine and 4,4',4''-tris(carbazole-9-yl)triphenylamine; The electron transport layer comprises beryllium phenylpyridinium, (8-hydroxyquinoline) lithium, ZnMgO, BAlq 3 , 1,3,5-tri(1-phenyl-1H-benzimidazol-2-yl)benzene, 1,3,5-tri[(3-pyridyl)-phenol-3-yl]benzene, 2,9-dimethyl-4,7-biphenyl-1,10-o-phenanthroline and one or more of 4,7-diphenyl-1,10-phenanthroline.

9. An electronic device, It is characterized in that The organic light emitting diode comprises the organic light emitting diode according to any one of claims 1 to 8.

Images