CN110416419B

CN110416419B - Organic electroluminescent device

Info

Publication number: CN110416419B
Application number: CN201810403470.0A
Authority: CN
Inventors: 张兆超; 李崇; 王立春
Original assignee: Jiangsu Sunera Technology Co Ltd
Current assignee: Jiangsu Sunera Technology Co Ltd
Priority date: 2018-04-28
Filing date: 2018-04-28
Publication date: 2021-03-26
Anticipated expiration: 2038-04-28
Also published as: CN110416419A; WO2019206290A1

Abstract

The invention relates to an organic electroluminescent device, which is sequentially provided with a substrate, a first electrode, an organic functional material layer and a second electrode from bottom to top, wherein the organic functional material layer sequentially comprises a hole transport region, a light emitting layer and an electron transport region from bottom to top, the hole transport region comprises a host material and a guest material, the hole transport region comprises a hole injection layer and/or a hole transport layer and an electron blocking layer positioned on the hole injection layer and/or the hole transport layer, the electron blocking layer comprises a first organic material and a second organic material which are doped according to the mass ratio of 0.5:9.5 to 9.5:0.5, the HOMO energy level of the first organic material is between the HOMO energy level of the host material of the light emitting layer and-5.75 ev, the HOMO energy level of the second organic material is between the HOMO energy level of the hole injection layer/the hole transport layer adjacent to the HOMO energy level of the second organic material and-5.75 ev, the LUMO energy levels of the first, The difference between the LUMO energy levels of the guest materials is not less than 0.2 eV.

Description

Organic electroluminescent device

Technical Field

The invention relates to the technical field of semiconductors, in particular to an organic electroluminescent device, and particularly relates to an organic electroluminescent device comprising an electron blocking layer.

Background

The organic electroluminescent device technology can be used for manufacturing novel display products and novel illumination products, is expected to replace the existing liquid crystal display and fluorescent lamp illumination, and has wide application prospect. When voltage is applied to electrodes at two ends of the organic electroluminescent device and an electric field acts on positive and negative charges in the organic layer functional material film layer, the positive and negative charges are further compounded in the organic light-emitting layer, and organic electroluminescence is generated.

Organic electroluminescent devices are generally multilayer structures, and various auxiliary functional layers other than the light-emitting layer also play a crucial role in device performance. The reasonable device structure can effectively improve the performance of the device, and the electron injection layer, the electron transport layer, the hole blocking layer, the luminescent layer, the electron blocking layer, the hole transport layer and the hole injection layer are widely used for improving the performance of the device.

The current research on the improvement of the performance of the organic electroluminescent device includes: the driving voltage of the device is reduced, the luminous efficiency of the device is improved, the service life of the device is prolonged, and the like. In order to realize the continuous improvement of the performance of the organic electroluminescent device, not only the innovation of the structure and the preparation process of the organic electroluminescent device is required, but also the continuous research and innovation of the organic electroluminescent functional material are required to manufacture the organic electroluminescent functional material with higher performance.

The carriers (holes and electrons) in the organic electroluminescent device are respectively injected into the device by two electrodes of the device under the drive of an electric field, and meet at a light-emitting layer to carry out recombination and light emission. It is known that a hole transport material used in a conventional organic electroluminescent device, for example, an aromatic amine derivative, has excellent hole mobility, but due to insufficient electron blocking property, a part of electrons pass through a light-emitting layer, and improvement of light-emitting efficiency cannot be expected.

In addition, in the organic electroluminescent device, the energy levels of all materials are not well matched, and the potential barrier between them seriously hinders the effective injection of holes. The reasonable energy level structure is beneficial to the formation of a step potential barrier by the energy levels in all layers of the device, the potential barrier of hole injection can be reduced, the driving voltage of the device is reduced, and therefore the luminous efficiency and the service life of the device are improved.

Therefore, there is a continuing need to develop organic electroluminescent devices having excellent luminous efficiency and lifetime.

Disclosure of Invention

The invention provides an organic electroluminescent device, which is sequentially provided with a substrate, a first electrode, an organic functional material layer and a second electrode from bottom to top, wherein the organic functional material layer comprises:

a hole transport region over the first electrode;

a light emitting layer including a host material and a guest material over the hole transport region;

an electron transport region located over the light emitting layer,

wherein the hole transport region comprises a hole injection layer and/or a hole transport layer over the first electrode and an electron blocking layer over it, an

The electron blocking layer material comprises first and second organic materials doped in a mass ratio of 0.5:9.5 to 9.5:0.5, wherein the Highest Occupied Molecular Orbital (HOMO) energy level of the first organic material is between the HOMO energy level of the light emitting layer host material and-5.75 ev, and the HOMO energy level of the second organic material is between the HOMO energy level of the hole injection layer/hole transport layer adjacent thereto and-5.75 ev;

the difference between the Lowest Unoccupied Molecular Orbital (LUMO) energy level of the first and second organic materials and the LUMO energy level of the host and guest materials of the light-emitting layer is more than or equal to 0.2 eV.

In an organic electroluminescent device comprising an electron blocking layer comprising the first and second organic materials of the present invention, the HOMO level of the material of the electron blocking layer is between-5.75 ev and the HOMO level of the hole injection layer/hole transport layer or the HOMO level of the host material of the light emitting layer, and this energy level matching reduces the barrier between the anode and the interface of the light emitting layer, which facilitates the injection of holes from the anode into the light emitting layer, improves the injection efficiency of holes, and reduces the driving voltage of the device; meanwhile, the LUMO energy level of the material of the electron blocking layer is higher than that of the light emitting layer, so that electrons are effectively blocked in the light emitting layer, the recombination probability of current carriers is improved, and the light emitting efficiency of the device is improved. Therefore, the electron blocking layer may have both a hole transporting function and an electron blocking function. Meanwhile, the higher triplet excited energy level of the electron blocking layer may trap excitons generated in the light emitting layer, thereby improving the light emitting efficiency of the device. In addition, the higher glass transition temperature of the electron blocking layer improves the heat resistance of the device.

Drawings

Fig. 1 schematically shows a cross-sectional view of an organic electroluminescent device according to an embodiment of the present invention;

fig. 2 schematically shows an energy transfer mechanism of an organic electroluminescent device according to an embodiment of the present invention.

Detailed Description

The invention will be described in more detail hereinafter with reference to the accompanying drawings, without intending to limit the invention thereto.

Any numerical range recited herein is intended to include all sub-ranges subsumed within the range with the same numerical precision. For example, "1.0 to 10.0" is intended to include all sub-ranges between (and including 1.0 and 10.0) the recited minimum value of 1.0 and the recited maximum value of 10.0, that is, all sub-ranges having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0. Any maximum numerical limitation recited herein is intended to include all smaller numerical limitations subsumed therein, and any minimum numerical limitation recited herein is intended to include all larger numerical limitations subsumed therein. Accordingly, applicants reserve the right to modify the specification, including the claims, to specifically describe any sub-ranges that fall within the ranges specifically described herein.

It is to be understood that the expression "the difference between the Lowest Unoccupied Molecular Orbital (LUMO) energy level of the first and second organic materials and the LUMO energy level of the host and guest materials of the light-emitting layer is 0.2ev or more" as used herein means that the difference between the lower value of the LUMO energy level in the first and second organic materials and the lower value of the LUMO energy level of the host and guest materials of the light-emitting layer is 0.2ev or more.

In the drawings, the size of layers and regions may be exaggerated for clarity. It will also be understood that when a layer or element is referred to as being "on" another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. In addition, it will also be understood that when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present. Like reference numerals refer to like elements throughout.

Hereinafter, an organic electroluminescent device according to an embodiment will be described.

Fig. 1 schematically shows a cross-sectional view of an organic electroluminescent device according to an embodiment of the present invention. Referring to fig. 1, the organic electroluminescent device according to an embodiment of the present invention includes a substrate 1, a first electrode 2, a hole transport region a, a light emitting layer 6, an electron transport region B, and a second electrode 10, which are sequentially disposed from bottom to top, wherein the hole transport region a sequentially includes a hole injection layer 3, a hole transport layer 4, and an electron blocking layer 5 from bottom to top, and the electron transport region B sequentially includes a hole blocking layer 7, an electron transport layer 8, and an electron injection layer 9 from bottom to top.

As the substrate of the organic electroluminescent device of the present invention, any substrate commonly used in organic electroluminescent devices can be selected. Examples are transparent substrates, such as glass or transparent plastic substrates; opaque substrates, such as silicon substrates; flexible PI film substrate. Different substrates have different mechanical strength, thermal stability, transparency, surface smoothness, water resistance, and use directions according to properties. In the present invention, a transparent substrate is preferably used. The thickness of the substrate is not particularly limited.

A first electrode is formed on the substrate, and the first electrode and the second electrode may be opposite to each other. The first electrode may be an anode. The first electrode may be a transmissive electrode, a semi-transmissive electrode, or a reflective electrode. When the first electrode is a transmissive electrode, the first electrode may be formed using a transparent metal oxide, such as Indium Tin Oxide (ITO), Indium Zinc Oxide (IZO), zinc oxide (ZnO), Indium Tin Zinc Oxide (ITZO), or the like. When the first electrode is a semi-transmissive electrode or a reflective electrode, the first electrode may include Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, or a metal mixture. The thickness of the first electrode layer depends on the material used and is typically 50-500nm, preferably 70-300nm and more preferably 100-200 nm.

The organic functional material layer arranged between the first electrode and the second electrode sequentially comprises a hole transmission area, a light emitting layer and an electron transmission area from bottom to top.

The hole transport region may be disposed between the first electrode and the light emitting layer. The hole transport region may include a hole injection layer, a hole transport layer, and an electron blocking layer, but is not limited thereto. For example, referring to fig. 1, the hole transport region may include a hole injection layer, a hole transport layer, and an electron blocking layer sequentially disposed on the first electrode from bottom to top.

In general, an organic material having a p-type property, which is easily oxidized and electrochemically stable when it is oxidized, is mainly used as a hole injection material or a hole transport material. Meanwhile, an organic material having n-type properties, which is easily reduced and electrochemically stable when reduced, is used as an electron injection material or an electron transport material. As the light emitting layer material, a material having both p-type and n-type properties, which is stable when it is oxidized and reduced, is preferable, and a material having a higher light emitting efficiency for converting excitons into light when the excitons are formed is also preferable.

The material of the hole injection layer is generally a material preferably having a high work function so that holes are easily injected into the organic material layer. Specific examples of the material of the hole injection layer include, but are not limited to, copper phthalocyanine, N '-diphenyl-N, N' -bis- [4- (phenyl-m-tolylamino) -phenyl ] -biphenyl-4, 4 '-diamine (DNTPD), 4', 4 ″ -tris (3-methylphenylphenylamino) triphenylamine (m-MTDATA), 4', 4 ″ -tris (N, N-diphenylamino) triphenylamine (TDATA), 4', 4 ″ -tris { N, - (2-naphthyl) -N-phenylamino } -triphenylamine (2TNATA), poly (3, 4-ethylenedioxythiophene)/poly (4-styrenesulfonate) (PEDOT/PSS), polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA), Polyaniline/camphorsulfonic acid (PANI/CSA) or (polyaniline)/poly (4-styrenesulfonate) (PANI/PSS). The thickness of the hole injection layer of the present invention may be 5 to 100nm, preferably 5 to 50nm and more preferably 5 to 20 nm.

The material of the hole transport layer is preferably a material having a high hole mobility, which enables holes to be transferred from the anode or the hole injection layer to the light-emitting layer. Specific examples of the material of the hole transport layer include, but are not limited to: carbazole-based derivatives such as N-phenylcarbazole or polyvinylcarbazole; a fluorene-based derivative; triphenylamine-based derivatives such as N, N ' -bis (3-methylphenyl) -N, N ' -diphenyl- [1, 1-biphenyl ] -4, 4' -diamine (TPD) and 4,4', 4 ″ -tris (N-carbazolyl) triphenylamine (TCTA), N ' -bis (1-naphthyl) -N, N ' -diphenyl benzidine (NPB), 4' -cyclohexylidene bis [ N, N-bis (4-methylphenyl) aniline ] (TAPC) and HT1 (specific structural formulae thereof will be shown below). According to the present invention, it is preferable to use HT1 as the hole transport layer material. The thickness of the hole transport layer of the present invention may be 5 to 200nm, preferably 10 to 150nm and more preferably 20 to 100 nm.

The hole injection layer and/or the hole transport layer may further include a charge generation material for improving conductivity. The charge generating material may be a p-dopant. Examples of non-limiting compounds of the P-dopant are, for example, quinone derivatives such as Tetracyanoquinodimethane (TCNQ) and 2,3,5, 6-tetrafluoro-tetracyano-1, 4-quinodimethane (F4-TCNQ); hexaazatriphenylene derivatives, such as 2,3,6,7,10, 11-hexacyano-1, 4,5,8,9, 12-hexaazatriphenylene (HAT-CN); cyclopropane derivatives, such as 4,4', 4 "- ((1E, 1' E, 1" E) -cyclopropane-1, 2, 3-trimethylenetri (cyanoformylidene)) tris (2,3,5, 6-tetrafluorobenzyl); metal oxides such as tungsten oxide and molybdenum oxide.

The electron blocking layer of the present invention may be disposed over the hole injection layer/hole transport layer. The electron blocking layer material comprises a first organic material and a second organic material, wherein the ratio of the first organic material to the second organic material is 0.5:9.5-9.5:0.5, preferably 3:7-7:3, more preferably 4:6-6:4 and most preferably 5:5 on a mass basis, and wherein the HOMO energy level of the first organic material is between the HOMO energy level of the host material of the light emitting layer and-5.75 ev and the HOMO energy level of the second organic material is between the HOMO energy level of the hole injection layer/hole transport layer adjacent thereto and-5.75 ev; the difference between the LUMO energy levels of the first and second organic materials and the LUMO energy level of the host-guest material of the light-emitting layer is not less than 0.2 ev.

Fig. 2 schematically shows an energy transfer mechanism of an organic electroluminescent device according to an embodiment of the present invention, wherein a represents a hole injection layer, b represents an electron blocking layer, c represents a guest of a light emitting layer, and d represents a host of the light emitting layer. And e represents an electron transport layer.

In one embodiment, the absolute value of the difference between the HOMO energy levels of the first organic material and the host material of the light-emitting layer is 0.3eV or less, and the absolute value of the difference between the HOMO energy levels of the second organic material and the hole injection layer material/hole transport layer material adjacent thereto is 0.3eV or less. The small energy barrier between the electron blocking material and the light emitting layer material allows holes to be easily injected into the light emitting layer via the electron blocking layer. The difference between the LUMO energy levels of the first and second organic materials and the LUMO energy level of the host-guest material of the light emitting layer is 0.2ev or more, preferably 0.3ev or more, and more preferably 0.5ev or more, which can effectively prevent electrons from being injected from the light emitting layer into the hole transporting region. Therefore, the electron blocking layer has both a hole transporting function and an electron blocking function.

According to one embodiment of the present invention, the first organic material may be selected from compounds comprising one or more of fluorene, azafluorene, spirofluorene, azaspirofluorene, acridine derivatives, mesitylene, carbazole or carbazole derivatives, examples being compounds having the following structural formula:

the above compounds EBI-1 to EBI-67 can be synthesized according to methods known to those skilled in the art, for example, the methods described in chinese patent applications having application numbers 201610797543.X, 2016102612529, 2016111795124, 2015107629517, 201610743566.2, 2016102592807, 2016111870337, 2016112071045, 2016111870500, 201610259334X, 2016112059518, 2017105481707, 2017104224787, 2017108995990, 2017109001681, 2017111804306 and 2017109097307, which are all incorporated herein by reference.

As the first organic material of the present invention, the above-mentioned (EBI-1), (EBI-3), (EBI-4), (EBI-7), (EBI-10), (EBI-11), (EBI-12), (EBI-14), (EBI-18), (EBI-22), (EBI-23), (EBI-29), (EBI-30), (EBI-31), (EBI-33), (EBI-34), (EBI-35), (EBI-37), (EBI-38), (EBI-39), (EBI-40), (EBI-44), (EBI-46), (EBI-48), (EBI-49), (EBI-52), (EBI-53), (EBI-58), (EBI-59), (EBI-60), and the like are preferably used, (EBI-63), (EBI-64) or (EBI-67), more preferably one or more of (EBI-1), (EBI-4), (EBI-7), (EBI-10), (EBI-14), (EBI-18), (EBI-23), (EBI-33), (EBI-35), (EBI-37), (EBI-39), (EBI-40), (EBI-44), (EBI-46), (EBI-48), (EBI-49), (EBI-53), (EBI-56), (EBI-60) or (EBI-64) described above.

According to one embodiment of the present invention, the second organic material may be selected from compounds comprising one or more of fluorene, azafluorene, spirofluorene, azaspirofluorene, phenoxazine, phenothiazine, phenoxazine derivatives, acridine derivatives, mesitylene, triarylamine, spiroxanthene fluorene or spirodimethylanthrene fluorene, examples being compounds having the following structural formula:

the above compounds EBII-1 to EBII-59 can be synthesized according to methods known to those skilled in the art, for example, the methods described in chinese patent applications having application numbers 2016112059861, 2016102612529, 2016111795124, 2015107629517, 2016112004214, 2016102592864, 2016111611012, 2016102620987, 2016102592807, 2016111870337, 201610797543.X, 2017108971089, 2017113683804 and 2017109090670, which are all incorporated herein by reference.

As the second organic material of the present invention, the above-mentioned (EBII-4), (EBII-6), (EBII-8), (EBII-10), (EBII-12), (EBII-13), (EBII-16), (EBII-20), (EBII-21), (EBII-22), (EBII-24), (EBII-25), (EBII-27), (EBII-29), (EBII-30), (EBII-31), (EBII-33), (EBII-34), (EBII-37), (EBII-38), (EBII-39), (EBII-42), (EBII-43), (EBII-46), (EBII-47), (EBII-48), (EBII-52), (EBII-53), (EBII-54), (EBII-56), (EBII-57) or (EBII-58), more preferably one or more of (EBII-4), (EBII-8), (EBII-10), (EBII-12), (EBII-21), (EBII-22), (EBII-24), (EBII-29), (EBII-34), (EBII-37), (EBII-38), (EBII-39), (EBII-42), (EBII-43), (EBII-46), (EBII-47), (EBII-52), (EBII-53), (EBII-56) or (EBII-57) described above.

The electron blocking layer material of the present invention has a hole mobility of 1 × 10^-5To 1X 10^-2cm²/(V.s), preferably 1X 10^-4To 1X 10^-2cm²V · s and more preferably 1 × 10^-4To 1X 10^-3cm²/(V·s)。

The glass transition temperature of the electron barrier material of the present invention is 120 ℃ or higher, preferably 130 ℃ or higher and more preferably 140 ℃ or higher.

The electron blocking layer of the present invention may have a thickness of 1 to 200nm, preferably 5 to 150nm, and more preferably 10 to 100 nm.

The light emitting layer may be disposed over the hole transport region. The material of the light-emitting layer is a material that can emit visible light by receiving holes and electrons from the hole-transporting layer and the electron-transporting layer, respectively, and combining the received holes and electrons, and is preferably a material having high quantum efficiency for fluorescence and phosphorescence. The light emitting materials are classified into blue, green and red light emitting materials according to their light emitting colors, and further into yellow and orange light emitting materials in order to realize more natural colors. Specific examples thereof include metal complexes of hydroxyquinoline derivatives, various metal complexes, anthracene derivatives, bisstyrylbenzene derivatives, pyrene derivatives, oxazole derivatives, polyparastyrene derivatives, and the like, but are not limited thereto. In addition, the light emitting layer may include a host material and a guest material. As the host material and guest material of the light-emitting layer of the organic electroluminescent device of the present invention, light-emitting layer materials for organic electroluminescent devices known in the art may be used, and the host material may be, for example, thiazole derivatives, benzimidazole derivatives, polydialkylfluorene derivatives, or 4,4' -bis (9-Carbazolyl) Biphenyl (CBP); the guest material may be, for example, quinacridone, coumarin, rubrene, perylene and derivatives thereof, benzopyran derivatives, rhodamine derivatives or aminostyrene derivatives.

In addition, the light emitting material may further include a phosphorescent or fluorescent material in order to improve fluorescent or phosphorescent characteristics. Specific examples of the phosphorescent material include phosphorescent materials of metal complexes of iridium, platinum, and the like. For example, Ir (ppy)₃[ fac-tris (2-phenylpyridine) iridium]And the like, blue phosphorescent materials such as FIrpic and FIr6, and red phosphorescent materials such as Btp2Ir (acac). For the fluorescent material, those known in the art can be used.

In addition, in addition to the fluorescent or phosphorescent host-guest materials used as described above, a non-host-guest doping system material used for a light emitting layer in an organic electroluminescent device, a host-guest material having a Thermally Activated Delayed Fluorescence (TADF) function, and a form in which a TADF functional material and the above-described fluorescent or phosphorescent materials are combined and matched with each other, which are well known in the art, may be used.

In the light-emitting layer of the present invention, the ratio of the host material to the guest material used is 99:1 to 70:30, preferably 99:1 to 85:15 and more preferably 97:3 to 87:13 on a mass basis.

The thickness of the light-emitting layer of the present invention may be 5 to 60nm, preferably 10 to 50nm, more preferably 20 to 45 nm.

In the present invention, the electron transport region may include, from bottom to top, a hole blocking layer, an electron transport layer, and an electron injection layer disposed over the light emitting layer, in this order, but is not limited thereto.

The hole blocking layer is a layer that blocks holes injected from the anode from passing through the light emitting layer to the cathode, thereby extending the lifetime of the device and improving the performance of the device. The hole blocking layer of the present invention may be disposed over the light emitting layer. As the hole-blocking layer material of the organic electroluminescent device of the present invention, compounds having a hole-blocking effect commonly known in the art, for example, phenanthroline derivatives such as bathocuproine (referred to as BCP), metal complexes of hydroxyquinoline derivatives such as aluminum (III) bis (2-methyl-8-quinoline) -4-phenylphenolate (BAlq), various rare earth complexes, oxazole derivatives, triazole derivatives, triazine derivatives, and the like can be used. The hole blocking layer of the present invention may have a thickness of 2 to 200nm, preferably 5 to 150nm, and more preferably 10 to 100 nm.

The electron transport layer may be disposed over the light-emitting layer or, if present, the hole blocking layer. The electron transport layer material is a material that easily receives electrons of the cathode and transfers the received electrons to the light emitting layer. Materials with high electron mobility are preferred. As the electron transport layer of the organic electroluminescent device of the present invention, electron transport layer materials for organic electroluminescent devices known in the art, for example, in Alq, can be used₃Metal complexes of hydroxyquinoline derivatives represented by BAlq, various metal complexes, triazole derivatives, triazine derivatives, oxadiazole derivatives, thiadiazole derivatives, carbodiimide derivatives, quinoxaline derivatives, phenanthroline derivatives, silicon-based compound derivatives, and the like. The thickness of the electron transport layer of the present invention may be 10 to 80nm, preferably 20 to 60nm, and more preferably 25 to 45 nm.

The electron injection layer may be disposed over the electron transport layer. The electron injection layer material is generally a material preferably having a low work function so that electrons are easily injected into the organic functional material layer. As the electron injection layer material of the organic electroluminescent device of the present invention, an electron injection layer material used in an organic electroluminescent device, which is known in the art, can be used, and examples thereof include alkali metal salts such as lithium fluoride (LiF) and cesium fluoride, alkaline earth metal salts such as magnesium fluoride, and metal oxides such as aluminum oxide. The thickness of the electron injection layer of the present invention may be 0.1 to 5nm, preferably 0.5 to 3nm, and more preferably 0.8 to 1.5 nm.

The second electrode may be disposed over the electron transport region. The second electrode may be a cathode. The second electrode EL2 may be a transmissive electrode, a semi-transmissive electrode, or a reflective electrode. When the second electrode is a transmissive electrode, the second electrode may include, for example, Li, Ca, LiF/Al, Mg, BaF, Ba, Ag, or compounds or mixtures thereof; when the second electrode is a semi-transmissive electrode or a reflective electrode, the second electrode may include Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF/Al, Mo, Ti, or a compound or mixture thereof.

The organic electroluminescent device of the present invention may be of a top emission type, a bottom emission type, or a double-sided emission type depending on the material used.

In the case where the organic electroluminescent device is of a top emission type, the first electrode may be a reflective electrode, and the second electrode may be a transmissive electrode or a semi-transmissive electrode. In the case where the organic electroluminescent device is of a bottom emission type, the first electrode may be a transmissive electrode or a semi-transmissive electrode, and the second electrode may be a reflective electrode.

The organic electroluminescent device may further include an encapsulation structure. The encapsulation structure may be a protective structure that prevents foreign substances such as moisture and oxygen from entering the organic layers of the organic electroluminescent device. The encapsulation structure may be, for example, a can, such as a glass can or a metal can; or a thin film covering the entire surface of the organic layer.

In the process of producing the organic electroluminescent device, the organic electroluminescent device of the present invention may be produced, for example, by sequentially laminating a first electrode, an organic functional material layer, and a second electrode on a substrate. In this regard, a physical vapor deposition method such as a sputtering method or an electron beam vapor method, or a vacuum evaporation method may be used, but is not limited thereto. Also, the above-mentioned compound can be used to form the organic functional material layer by, for example, a vacuum deposition method, a vacuum evaporation method, or a solution coating method. In this regard, the solution coating method means spin coating, dip coating, jet printing, screen printing, spraying, and roll coating, but is not limited thereto. Vacuum evaporation means that a material is heated and plated onto a substrate in a vacuum environment. In the present invention, it is preferable that the respective layers are formed by a vacuum evaporation method.

The material for forming each layer according to the present invention may be used as a single layer by forming a film alone, may be used as a single layer by forming a film in admixture with another material, or may be used as a laminated structure of layers formed alone, layers formed in admixture with each other, or a laminated structure of layers formed alone and layers formed in admixture with each other.

Exemplary embodiments have been disclosed herein, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation. In some instances, features, characteristics and/or elements described in connection with a particular embodiment may be used alone or in combination with features, characteristics and/or elements described in connection with other embodiments, unless specifically indicated otherwise, as will be apparent to one of ordinary skill in the art upon submission of the present application. Accordingly, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

The following examples are intended to better illustrate the invention, but the scope of the invention is not limited thereto.

Examples

The detection method used herein is as follows:

glass transition temperature Tg: measured by differential scanning calorimetry (DSC, DSC204F1 DSC of German Nasicon company), the heating rate is 10 ℃/min;

HOMO energy level: vacuum evaporation equipment is used, and the vacuum degree is 1.0E^-5Under Pa pressure, the evaporation rate is controlled to be

Evaporating a material onto an ITO substrate, and then testing by using an ionization energy testing system (IPS3) to obtain a vacuum environment;

eg energy level: a tangent line is drawn based on the ultraviolet spectrophotometric (UV absorption) baseline of the single film of the material and the rising side of the first absorption peak, and the numerical value of the intersection point of the tangent line and the baseline is calculated.

LUMO energy level: and calculating based on the difference between the HOMO energy level and the Eg energy level.

Work function of electrode material: the test was carried out in an atmospheric environment using a surface work function tester developed by the university of shanghai.

Hole mobility: the material was fabricated into single charge devices and tested by the SCLC method.

Preparation of an Electron Barrier Material

I. Preparation of the first organic material used:

EBI-1：synthesized according to the following process:

(1)

in a 250mL three-necked flask, 0.02mol of 4-dibenzofuranboronic acid and 0.03mol of 3, 5-dibromo-1, 1' -biphenyl were added under a nitrogen atmosphere, and the mixture was dissolved by adding a mixed solvent (90mL of toluene and 45mL of ethanol), followed by addition of 0.06mol of Na₂CO₃The aqueous solution (2M) was stirred under nitrogen for 1 hour. Then, 0.0002mol of Pd (PPh) was added₃)₄The reaction was heated to 100 ℃ and refluxed for 15 hours, and the reaction was observed by Thin Layer Chromatography (TLC) until the reaction was completed. Naturally cooling to room temperature, filtering, and performing reduced pressure rotary evaporation on the filtrate until no fraction is obtained. The resulting material was purified by silica gel column (petroleum ether as eluent) to afford intermediate a1, 99.8% purity by High Performance Liquid Chromatography (HPLC) and 57.9% yield.

Elemental analysis Structure (molecular formula C)₂₄H₁₅BrO): theoretical value C, 72.19; h, 3.79; br, 20.01; o, 4.01; test values are: c, 72.17; h, 3.78; br, 20.03; and O, 4.02.

HPLC-MS: the theoretical molecular weight of the material is 398.03, and the measured molecular weight is 398.61.

(2)

To a 250mL three-necked flask, 0.04mol of B1 as a starting material, 0.06mol of 1, 3-dibromobenzene, 0.12mol of sodium tert-butoxide, and 4X 10 in a nitrogen atmosphere were charged^-4mol Pd₂(dba)₃、4×10^-4mol tri-tert-butyl phosphine, 150ml toluene, heating to 120 ℃, refluxing for 24 hours, and observing the reaction by TLC until the reaction is complete. Naturally cooling to room temperature, filtering, and rotatably evaporating the filtrate until no fraction is obtained. The obtained material was passed through silica gelColumn purification (petroleum ether as eluent) gave intermediate C1 in 99.1% purity by HPLC and 62.2% yield.

Elemental analysis structure: (formula C)₂₇H₂₀BrN): theoretical value C, 73.98; h, 4.60; br, 18.23; n, 3.20; test values are: c, 73.96; h, 4.61; br, 18.21; and N, 3.22.

HPLC-MS: the theoretical molecular weight of the material is 437.08, and the measured molecular weight is 437.53.

(3)

To a 250mL three-necked flask, 0.02mol of the prepared intermediate C1 was added under nitrogen, followed by addition of 40mL of tetrahydrofuran to completely dissolve it and cooling to-78 ℃. Then, 15mL of a 1.6mol/L solution of n-butyllithium in tetrahydrofuran was added to the reaction system, and after reacting at-78 ℃ for 3 hours, 0.024mol of triisopropyl borate was added, and the reaction was further carried out for 2 hours. Then, the reaction system was heated to 0 ℃ and 50mL of a 2mol/L hydrochloric acid solution was added and stirred for 3 hours to complete the reaction. Thereafter, ether was added for extraction, and the extract was dried over anhydrous magnesium sulfate, rotary-distilled, and then recrystallized from an ethanol solvent to obtain intermediate D1 with an HPLC analytical purity of 99.1% and a yield of 62.2%.

Elemental analysis structure: (formula C)₂₇H₂₂BNO₂): theoretical value C, 80.41; h, 5.50; b, 2.68; n, 3.47; o, 7.93; test values are: c, 80.43; h, 5.52; b, 2.69; n, 3.45; and O, 7.91.

HPLC-MS: the theoretical molecular weight of the material is 403.17, and the measured molecular weight is 403.49.

(4)

To a 250mL three-necked flask, 0.01mol of the obtained intermediate a1 and 0.015mol of the obtained intermediate D1 were added under a nitrogen atmosphere, and then dissolved by adding a mixed solvent (90mL of toluene and 45mL of ethanol). Then add0.03mol of Na is added₂CO₃The aqueous solution (2M) was stirred under nitrogen for 1 hour, then 0.0001mol of Pd (PPh) was added₃)₄The reaction was heated to 100 ℃ and refluxed for 15 hours, and the reaction was observed by TLC until the reaction was complete. Naturally cooling to room temperature, filtering, and rotatably evaporating the filtrate until no fraction is obtained. The resulting material was purified by silica gel column (n-hexane as eluent) to obtain the target product EBI-1 with HPLC analysis purity of 99.4% and yield of 66.2%.

Elemental analysis Structure (molecular formula C)₅₁H₃₅NO): theoretical value C, 90.37; h, 5.20; n, 2.07; o, 2.36; test values are: c, 90.38; h, 5.21; n, 2.06; o, 2.35.

HPLC-MS: the theoretical molecular weight of the material is 677.27, and the measured molecular weight is 677.55.

EBI-37：Synthesized according to the following process:

(1)

under nitrogen atmosphere, 0.05mol of bromobenzene and 0.06mol of Mg powder are added into a 250mL three-neck bottle, then 60mL of dry tetrahydrofuran is added to dissolve the bromobenzene, and then 0.0004mol of simple substance I is added₂. The reaction mixture was heated to 40 ℃ and stirred until the solution turned from yellow to colorless. And heating the mixed solution to 80 ℃, stirring and reacting for 4 hours until no magnesium powder remains, and completely reacting to obtain a Grignard reagent intermediate V1.

(2)

To a 250mL three-necked flask, 0.03mol of 9-fluorenone was added under a nitrogen atmosphere, followed by the addition of 40mL of dry tetrahydrofuran to dissolve it. Then, the Grignard reagent intermediate V1 solution was slowly added dropwise, heated to 80 ℃ and reacted under reflux for 15 hours to produce a large amount of white precipitated Grignard salt. It was then cooled to room temperature and saturated NHCl was added₄Converting the grignard salt toAn alcohol; after the reaction was complete, it was extracted with ether, dried, rotary evaporated and purified through silica gel column (ethyl acetate as eluent) to give the slightly yellowish solid tertiary alcohol intermediate W1 with 99.2% purity by HPLC and 72.5% yield.

(3)

To a 250mL three-necked flask, 0.02mol of the resulting intermediate W1 was added under a nitrogen atmosphere, followed by dissolving it in 50mL of toluene. Then, 48% aqueous HBr (40ml) is slowly dropped, the reaction is stirred at 25 ℃ for 24 hours, liquid separation is carried out after the reaction is finished, the aqueous phase is extracted by toluene, the organic phases are combined and dried by anhydrous sodium sulfate, then suction filtration is carried out, the filter cake is washed by ethyl acetate, and the filtrate and the washing liquid are evaporated in a rotary manner until no solvent exists. The resulting material was purified over a silica gel column (petroleum ether as eluent) to afford intermediate M1 with an HPLC analytical purity of 99.2% and a yield of 75.9%.

Elemental analysis Structure (molecular formula C)₁₉H₁₃Br): theoretical value C, 71.04; h, 4.08; br, 24.88; test values are: c, 71.07; h, 4.06; br, 24.87.

HPLC-MS: theoretical value is 320.02, found 320.52.

(4)

In a 250mL three-necked flask, 0.02mol of A1 as a starting material, 0.024mol of 3-bromo-1, 1' -biphenyl, 0.05mol of sodium tert-butoxide, and 1.0X 10 mol of sodium tert-butoxide were charged under a nitrogen atmosphere^-4mol Pd₂(dba)₃、1.0×10^-4And (3) adding 150ml of toluene to dissolve the tri-tert-butylphosphine, heating to 120 ℃, refluxing for 10 hours, and observing the reaction by TLC until the reaction is complete. Naturally cooling to room temperature, filtering, and rotatably evaporating the filtrate until no fraction is obtained. The resulting material was purified over silica gel column (petroleum ether as eluent) to afford intermediate O1 with an HPLC analytical purity of 99.5% and a yield of 85.7%。

Elemental analysis Structure (molecular formula C)₃₃H₂₅N): theoretical value C, 91.00; h, 5.79; n, 3.22; test values are: c, 90.97; h, 5.80; and N, 3.23.

HPLC-MS: theoretical value is 435.20, found 435.66.

(5)

Weighing 0.02mol of intermediate O1, dissolving in 50ml of acetic acid, and cooling to 0 ℃ by using an ice salt bath; weighing 0.015mol of liquid bromine, dissolving the liquid bromine in glacial acetic acid, slowly dropwise adding the liquid bromine into an acetic acid solution of an intermediate O1, stirring for 5 hours at room temperature, observing the reaction by using TLC (thin layer chromatography) until the intermediate O1 is remained, and completely reacting; after the reaction, Na was added to the reaction mixture₂CO₃Neutralizing the solution, extracting with dichloromethane, layering, filtering the organic phase, vacuum rotary distilling the filtrate until no fraction is obtained, and passing through silica gel column (petroleum ether as eluent) to obtain intermediate O2;

weighing 0.01mol of intermediate O2 in 100ml of tetrahydrofuran under the protection of nitrogen, dissolving in 100ml of tetrahydrofuran, cooling to-78 ℃, adding 1.6mol/L of n-butyllithium tetrahydrofuran solution into a reaction system, reacting for 3h at-78 ℃, adding 0.02mol of triisopropyl borate, reacting for 2h, raising the temperature of the reaction system to 0 ℃, adding 50ml of 2mol/L hydrochloric acid solution, stirring for 3h, completely reacting, adding diethyl ether for extraction, adding anhydrous magnesium sulfate into an extract, drying, rotary steaming, and recrystallizing by using an ethanol solvent to obtain the intermediate O3.

Elemental analysis Structure (molecular formula C)₃₃H₂₆BNO₂): theoretical value C, 82.68; h, 5.47; b, 2.26; n, 2.92; o, 6.68; test values are: c, 82.69; h, 5.49; b, 2.24; n, 2.93; o, 6.65.

HPLC-MS: theoretical value is 479.21, found 479.58.

(6)

To a 250mL three-necked flask, 0.01mol of intermediate M1 and 0.015mol of intermediate O3 were added under a nitrogen atmosphere, and then dissolved by adding a mixed solvent (90mL of toluene and 45mL of ethanol). Then 0.03mol of Na is added₂CO₃Aqueous solution (2M), stirred under nitrogen for 1 hour, then added with 0.0001mol Pd (PPh3)4, heated to 100 deg.C, refluxed for 15 hours, and observed by TLC until the reaction was complete. Naturally cooling to room temperature, filtering, and rotatably evaporating the filtrate until no fraction is obtained. The resulting material was purified by column on silica gel (toluene as eluent) to give the desired product EBI-37 in 99.5% purity by HPLC and 76.4% yield.

Elemental analysis Structure (molecular formula C)₅₂H₃₇N): theoretical value C, 92.41; h, 5.52; n, 2.07; test values are: c, 92.42; h, 5.54; and N, 2.04.

HPLC-MS: theoretical value is 675.29, found 675.55.

EBI-49：Synthesized according to the following process:

(1)

under a nitrogen atmosphere, 0.05mol of the raw material I and 0.075mol of the raw material II were added to a 250mL three-necked flask, and then dissolved by adding a mixed solvent (90mL of toluene and 45mL of ethanol), followed by adding 0.15mol of Na₂CO₃The aqueous solution (2M) was stirred under nitrogen for 1 hour, then 0.0005mol Pd (PPh) was added₃)₄The reaction was heated to 100 ℃ and refluxed for 15 hours, and the reaction was observed by Thin Layer Chromatography (TLC) until the reaction was completed. Naturally cooling to room temperature, filtering, and rotatably evaporating the filtrate until no fraction is obtained. The resulting material was purified over a silica gel column (ethyl acetate as eluent) to afford intermediate I in 99.1% purity by HPLC and 77.3% yield.

Elemental analysis Structure (molecular formula C)₄₀H₂₇NO₂): theoretical value C, 86.78; h, 4.92; n, 2.53; o, 5.78; test values are: c, 86.77; h, 4.91; n, 2.55; and O, 5.77.

HPLC-MS: theoretical value is 553.20, found 553.56.

(2)

Under a nitrogen atmosphere, 0.03mol of intermediate I and 0.036mol of triphenylphosphine were added into a 250mL three-necked flask, and then 50mL of o-dichlorobenzene was added to dissolve the intermediate I and the resulting solution, and the reaction was heated to 170 ℃ for 15 hours, and the reaction was observed by TLC until the reaction was complete. Naturally cooling to room temperature, filtering, and rotatably evaporating the filtrate until no fraction is obtained. The resulting material was purified by column on silica gel (petroleum ether as eluent) to afford intermediate II with 99.3% purity by HPLC and 76.6% yield.

Elemental analysis Structure (molecular formula C)₄₀H₂₇N): theoretical value C, 92.10; h, 5.22; n, 2.69; test values are: c, 92.09; h, 5.21; and N, 2.70.

HPLC-MS: theoretical value is 521.21, found 521.68.

(3)

Under a nitrogen atmosphere, a 250mL three-necked flask was charged with 0.01mol of intermediate II, 0.012mol of bromobenzene, 0.03mol of sodium tert-butoxide, and 5X 10-5mol of Pd₂(dba)₃、5×10^-5And (3) adding 150ml of toluene to dissolve the tri-tert-butylphosphine, heating to 120 ℃, and refluxing for 24 hours to observe the reaction by TLC until the reaction is complete. Naturally cooling to room temperature, filtering, and rotatably evaporating the filtrate until no fraction is obtained. The resulting material was purified by silica gel column (toluene as eluent) to give the desired product, EBI-49, 99.4% purity by HPLC analysis, in 78.1% yield.

Elemental analysis Structure (molecular formula C)₄₆H₃₁N): theoretical value C, 92.43; h, 5.23; n, 2.34; test values are: c, 92.44; h, 5.21; and N, 2.35.

HPLC-MS: theoretical value is 597.25, found 597.72.

Preparation of the second organic material used:

EBII-21：synthesized according to the following process:

(1)

0.05mol of N- ([1, 1' -biphenyl ] -2-yl) -N- (4-bromophenyl) -9, 9-dimethylfluoren-3-amine and 0.06mol of Mg powder, 60mL of tetrahydrofuran were added to a 250mL four-necked flask under a nitrogen atmosphere, heated to 80 ℃ and refluxed for 4 hours until the reaction was completed to obtain the Grignard reagent (i.e., intermediate P1).

(2)

Dissolving 0.05mol of 10, 10-dimethyl anthrone in 50ml of tetrahydrofuran, dropwise adding the Grignard reagent P1, reacting at 60 ℃ for 24 hours to generate a large amount of white precipitated Grignard salt, and finally adding saturated NHCl₄Converting the grignard salt to an alcohol. After completion of the reaction, the reaction mixture was extracted with ether, dried and rotary-distilled, and the resulting substance was purified by means of a silica gel column (petroleum ether: dichloromethane mixed solvent (3:2) as an eluent) to obtain a slightly yellowish solid tertiary alcohol (i.e., intermediate Q1) (yield 85%).

Elemental analysis Structure (molecular formula C)₄₉H₄₁NO): theoretical value C, 89.19; h, 6.26; n, 2.12; o, 2.42; test values are: c, 89.21; h, 6.27; n, 2.11; o, 2.41.

HPLC-MS: theoretical value is 659.32, found 659.77.

(3)

0.04mol of the tertiary alcohol (intermediate Q1) and 0.06mol of benzene are dissolved in 100ml of dichloromethane according to 1:1.5 equivalent, 8ml of boron trifluoride-diethyl ether complex is added dropwise at room temperature for reaction for 30 minutes, 20ml of ethanol and 20ml of water are added for quenching reaction, then dichloromethane (20ml of 3) is used for extraction, and drying and rotary evaporation are carried out. The resulting material was purified by column on silica gel (petroleum ether as eluent), followed by recrystallization from ethanol, dichloromethane (1:2), to give the desired product, EBII-21 (yield 68%).

Elemental analysis Structure (molecular formula C)₅₅H₄₅N): theoretical value C, 91.75; h, 6.30; n, 1.95; test values are: c, 91.76; h, 6.31; n, 1.93.

HPLC-MS: theoretical value is 719.36, found 719.81.

EBII-39：Synthesized according to the following process:

(1)

under the nitrogen atmosphere, 10.6mmol of 1, 1' -bis (diphenylphosphino) ferrocene, 10.6mmol of palladium acetate, 921mmol of sodium tert-butoxide, 709mmol of biphenyl-4-amine and 709mmol of 4-bromo-9, 9-spirobifluorene are added into a 1L three-necked bottle and dissolved in 400ml of toluene, the mixture is heated to 120 ℃, reflux reaction is carried out for 20 hours, after the reaction is finished, the mixture is cooled to room temperature, filtered, and filtrate is evaporated in a rotary manner. Purification through silica gel column (n-hexane as eluent) and recrystallization from isopropanol gave intermediate X as a pale yellow solid in 87% yield.

Elemental analysis Structure (molecular formula C)₃₇H₂₅N): theoretical value C, 91.89; h, 5.21; n, 2.90; test values are: c, 91.89; h, 5.20; and N, 2.91.

HPLC-MS: theoretical value is 483.20, found 483.63.

(2)

Under nitrogen atmosphere, 4.4ml of 1.0M tri-tert-butylphosphine toluene solution, 1.1mmol of palladium acetate, 166mmol of sodium tert-butoxide, 110mmol of intermediate X, 140mmol of 2-bromo-9, 9-dimethylfluorene and 500ml of toluene were added to a 1L three-necked flask, heated to 120 ℃ and refluxed for 10 hours, after the reaction was completed, cooled to room temperature, filtered, the filtrate was evaporated and purified by a silica gel column (toluene as eluent), and then recrystallized with ethyl acetate to obtain the target product EBII-39 with an HPLC analytical purity of 99.7% and a yield of 69.9%.

Elemental analysis Structure (molecular formula C)₅₂H₃₇N): theoretical value C, 92.41; h, 5.52; n, 2.07; test values are: c, 92.44; h, 5.51; and N, 2.05.

HPLC-MS: theoretical value is 675.29, found 675.74.

EBII-48: synthesized according to the following process;

into a 250ml three-necked flask, 0.01mol of the raw material A, 0.012mol of the raw material B, 0.03mol of potassium tert-butoxide, 1X 10 mol were charged in a nitrogen atmosphere^-4molPd₂(dba)₃、1×10^-4mol tri-tert-butylphosphine and 150ml toluene were heated to 120 ℃ and refluxed for 12 hours, and the reaction was observed by TLC until the reaction was complete. Naturally cooling to room temperature, filtering, and rotatably evaporating the filtrate until no fraction is obtained. The resulting material was purified by column on silica gel (toluene as eluent) to give the target compound EBII-48 with an HPLC analytical purity of 99.4% and a yield of 81.5%.

Elemental analysis Structure (molecular formula C)₅₂H₃₉N): theoretical value C, 92.13; h, 5.80; n, 2.07; test values are: c, 92.13; h, 5.82; and N, 2.05.

HPLC-MS: theoretical value is 677.87, found 678.35.

Table 1 shows the host material CBP, the guest material Ir (PPy) of the first and second organic materials and the light emitting material used₃And the results of the energy level tests of the hole transport material HT1 adjacent thereto.

TABLE 1

As can be seen from the results of table 1, the HOMO level of the first organic material of the present invention is between the HOMO level of the host material of the light emitting layer and-5.75 ev, and the HOMO level of the second organic material is between the HOMO level of the hole transport layer material adjacent thereto and-5.75 ev; and the difference between the LUMO energy levels of the first and second organic materials and the LUMO energy levels of the host material and the guest material of the light-emitting layer is more than or equal to 0.2 ev.

Example 1

EBI-1 and EBII-39 were placed in two evaporation sources, respectively, using a CIC evaporation apparatus (manufactured by the Changzhou industry) at a vacuum of 1.0E^-5Under the pressure of Pa, the EBI-1 evaporation rate is controlled to be

The EBII-39 evaporation rate is controlled to be

Co-evaporation to obtain the electron barrier material 1 of the present invention.

Example 2

The procedure of example 1 was repeated except that EBI-1 had a vapor deposition rate of

EBII-39 has a vapor deposition rate of

An electron blocking layer material 2 is obtained.

Example 3

EBII-39 has a vapor deposition rate of

To obtainAn electron blocking layer material 3.

Example 4

The procedure of example 1 was repeated except that EBI-37 and EBII-21 were used to obtain an electron blocking layer material 4.

Example 5

The procedure of example 1 was repeated except that EBI-49 and EBII-48 were used, to obtain an electron blocking layer material 5.

Preparation of organic electroluminescent device

The vacuum deposition was performed under the following conditions: using CIC vapor deposition equipment (manufactured by Changzhou industry), the vacuum degree was 1.0E^-5Under Pa pressure, the evaporation rate is controlled to be

Device preparation example 1

The method comprises the following steps:

a) using transparent glass as a substrate, coating ITO with the thickness of 150nm on the transparent glass as an anode layer, then respectively ultrasonically cleaning the transparent glass with deionized water, acetone and ethanol for 15 minutes, and then treating the transparent glass in a plasma cleaner for 2 minutes;

b) evaporating HAT-CN on the washed first electrode layer by a vacuum evaporation method, wherein the thickness of the HAT-CN is 10nm, and the layer is used as a hole injection layer;

c) evaporating HT1 on the hole injection layer by vacuum evaporation, wherein the thickness is 90nm, and the layer is a hole transport layer;

d) the electron barrier material 1 obtained in example 1 for preparing an electron barrier material was evaporated on the hole transport layer by vacuum evaporation, with a thickness of 20nm, and this layer was an electron barrier layer;

e) depositing a luminescent layer material on the electron barrier layer by vacuum evaporation, wherein the host material is CBP, and the doping material is Ir (PPy)₃CBP and Ir (PPy)₃The mass ratio is 90:10, and the thickness is 40 nm;

f) evaporating TPBI on the light-emitting layer in a vacuum evaporation mode, wherein the thickness of the TPBI is 40nm, and the TPBI serves as an electron transport layer;

g) evaporating LiF on the electron transport layer in a vacuum evaporation mode, wherein the thickness of the LiF is 1nm, and the LiF is an electron injection layer;

h) vacuum evaporating Al on the electron injection layer, wherein the thickness of the Al is 100nm, and the layer is a second electrode layer;

wherein, the structural formula of the related material is as follows:

device production example 2

The procedure of device preparation example 1 was followed, except that the electron blocking layer material 2 obtained in example 2 for preparing an electron blocking layer material was used in step d).

Device production example 3

The procedure of device preparation example 1 was followed, except that the electron barrier material 3 obtained in example 3 for the preparation of an electron barrier material was used in step d).

Device preparation example 4

The procedure of device preparation example 1 was followed, except that the electron blocking layer material 4 obtained in example 4 for the preparation of an electron blocking layer material was used in step d).

Device preparation example 5

The procedure of device preparation example 1 was followed, except that the electron barrier material 5 obtained in example 5 for the preparation of an electron barrier material was used in step d).

Comparative example 1

The procedure of device fabrication example 1 was followed except that only EBI-1 was used as an electron blocking layer material.

Comparative example 2

The procedure of device preparation example 1 was followed except that only EBII-39 was used as an electron blocking layer material.

Comparative example 3

The procedure of device fabrication example 1 was followed except that only EBI-37 was used as an electron blocking layer material.

Comparative example 4

The procedure of device fabrication example 1 was followed except that only EBI-49 was used as an electron blocking layer material.

Comparative example 5

The procedure of device fabrication example 1 was followed except that only EBII-21 was used as an electron blocking layer material.

Comparative example 6

The procedure of device fabrication example 1 was followed except that only EBII-48 was used as an electron blocking layer material.

Table 3 shows the values at 10mA/cm²The performance of the fabricated organic electroluminescent device was measured at current density.

TABLE 3

Note: representative of comparative examples

LT90 refers to the time it takes for the device luminance to decay to 90% at a constant current density of 10mA/cm 2.

The life test system is an OLED device life tester which is researched by the owner of the invention together with Shanghai university.

As can be seen from the results of table 3, the device of the present invention according to preparation examples 1 to 5 had significantly reduced driving voltage and significantly improved light emission luminance, light emission efficiency (i.e., current efficiency) and lifetime, as compared to comparative examples 1 to 6 using an organic material alone as an electron blocking layer material.

Finally, the above embodiments are only used to illustrate the technical solution of the present invention and are not limited. Modifications and equivalents of the present invention may be made by those skilled in the art without departing from the spirit and scope of the present invention, and are intended to be included within the scope of the appended claims.

Claims

1. An organic electroluminescent device is provided with a substrate, a first electrode, an organic functional material layer and a second electrode in sequence from bottom to top, wherein the organic functional material layer comprises

A hole transport region over the first electrode;

an electron transport region located over the light emitting layer,

The electron blocking layer includes first and second organic materials in a ratio of 0.5:9.5 to 9.5:0.5 on a mass basis; and wherein the HOMO level of the first organic material is between-5.75 eV and the HOMO level of the host material of the light-emitting layer, and the HOMO level of the second organic material is between-5.75 eV and the HOMO level of the hole injection layer/hole transport layer adjacent thereto, and the difference between the LUMO levels of the first and second organic materials and the LUMO levels of the host and guest materials of the light-emitting layer is 0.2eV or more.

2. The organic electroluminescent device according to claim 1, wherein the ratio of the first and second organic materials is 3:7 to 7:3 on a mass basis.

3. The organic electroluminescent device according to claim 2, wherein the ratio of the first and second organic materials is 4:6 to 6:4 on a mass basis.

4. The organic electroluminescent device according to claim 3, wherein the ratio of the first and second organic materials is 5:5 on a mass basis.

5. The organic electroluminescent device according to claim 1, wherein the absolute value of the difference between the HOMO energy levels of the first organic material and the host material of the light-emitting layer is 0.3ev or less, and the absolute value of the difference between the HOMO energy levels of the second organic material and the hole injection layer material/hole transport layer material adjacent thereto is 0.3ev or less.

6. An organic electroluminescent device according to claim 1, wherein the first organic material is selected from compounds comprising one or more of fluorene, azafluorene, spirofluorene, azaspirofluorene, acridine derivatives, mesitylene, carbazole or carbazole derivatives.

7. The organic electroluminescent device according to claim 6, wherein the first organic material is a compound having the following structural formula:

8. the organic electroluminescent device according to claim 7, wherein the first organic material is a compound (EBI-1), (EBI-3), (EBI-4), (EBI-7), (EBI-10), (EBI-11), (EBI-12), (EBI-14), (EBI-18), (EBI-22), (EBI-23), (EBI-29), (EBI-30), (EBI-31), (EBI-33), (EBI-34), (EBI-35), (EBI-37), (EBI-38), (EBI-39), (EBI-40), (EBI-44), (EBI-46), (EBI-48), (EBI-49), (EBI-52), (EBI-53), (EBI-58), One or more of (EBI-59), (EBI-60), (EBI-63), (EBI-64) or (EBI-67).

9. The organic electroluminescent device according to claim 8, wherein the first organic material is one or more of compounds (EBI-1), (EBI-4), (EBI-7), (EBI-10), (EBI-14), (EBI-18), (EBI-23), (EBI-33), (EBI-35), (EBI-37), (EBI-39), (EBI-40), (EBI-44), (EBI-46), (EBI-48), (EBI-49), (EBI-53), (EBI-56), (EBI-60), or (EBI-64).

10. An organic electroluminescent device according to claim 1, wherein the second organic material may be selected from compounds comprising one or more of fluorene, azafluorene, spirofluorene, azaspirofluorene, phenoxazine, phenothiazine, phenoxazine derivatives, acridine derivatives, mesitylene, triarylamine, spiroxanthene fluorene or spirodimethylanthrene fluorene.

11. The organic electroluminescent device according to claim 10, wherein the second organic material is a compound having the following structural formula:

12. the organic electroluminescent device according to claim 11, wherein the second organic material is a compound (EBII-4), (EBII-6), (EBII-8), (EBII-10), (EBII-12), (EBII-13), (EBII-16), (EBII-20), (EBII-21), (EBII-22), (EBII-24), (EBII-25), (EBII-27), (EBII-29), (EBII-30), (EBII-31), (EBII-33), (EBII-34), (EBII-37), (EBII-38), (EBII-39), (EBII-42), (EBII-43), (EBII-46), (EBII-47), (EBII-48), (EBII-52), (EBII-53), One or more of (EBII-54), (EBII-56), (EBII-57) or (EBII-58).

13. The organic electroluminescent device according to claim 12, wherein the second organic material is one or more of compounds (EBII-4), (EBII-8), (EBII-10), (EBII-12), (EBII-21), (EBII-22), (EBII-24), (EBII-29), (EBII-34), (EBII-37), (EBII-38), (EBII-39), (EBII-42), (EBII-43), (EBII-46), (EBII-47), (EBII-52), (EBII-53), (EBII-56), or (EBII-57).

14. The organic electroluminescent device according to any one of claims 1 to 13, wherein the hole mobility of the electron blocking layer is 1 x 10^-5To 1X 10^-2cm²/(V·s)。

15. The organic electroluminescent device according to claim 14, wherein the hole mobility of the electron blocking layer is 1 x 10^-4To 1X 10^-2cm²/(V·s)。

16. The organic electroluminescent device according to claim 15, wherein the hole mobility of the electron blocking layer is 1 x 10^-4To 1X 10^-3cm²/(V·s)。

17. The organic electroluminescent device according to any one of claims 1 to 13, wherein the glass transition temperature of the electron blocking layer is 120 ℃ or more.

18. The organic electroluminescent device according to claim 17, wherein the glass transition temperature of the electron blocking layer is 130 ℃ or more.

19. The organic electroluminescent device according to claim 18, wherein the glass transition temperature of the electron blocking layer is 140 ℃ or more.

20. The organic electroluminescent device according to any one of claims 1 to 13, wherein the thickness of the electron blocking layer is 1-200 nm.

21. The organic electroluminescent device according to claim 20, wherein the electron blocking layer has a thickness of 5-150 nm.

22. The organic electroluminescent device according to claim 21, wherein the electron blocking layer has a thickness of 10-100 nm.