KR20210016971A - Organic electroluminescent device - Google Patents

Abstract

Provided is an organic electroluminescent device, in which a corresponding light emitting layer material and an electron transport auxiliary layer material are mixed between a light emitting layer and an electron transport auxiliary layer to provide a co-deposited organic functional layer, so as to provide high luminous efficiency, low driving voltage, and long life.

Description

Organic electroluminescent device {ORGANIC ELECTROLUMINESCENT DEVICE}

The present invention is an organic electroluminescent device that simultaneously exhibits high luminous efficiency, low driving voltage, and long life by separately providing an organic functional layer in which the material of the light-emitting layer and the material of the electron-transport auxiliary layer are mixed between the light-emitting layer and the auxiliary layer for transporting electrons. Can provide.

In 1965, research on an organic electroluminescent (EL) device (hereinafter simply referred to as'organic EL device') followed by blue electroluminescence using an anthracene single crystal (hereinafter, simply referred to as'organic EL device') was continued, and in 1987 the hole layer was formed by Tang. An organic EL device having a two-layer stack structure composed of (NPB) and a light emitting layer (Alq ₃ ) has been proposed. Afterwards, the organic EL device induces electroluminescence to occur by the combination of holes and electrons, an organic layer in charge of hole injection and transport, an organic layer in charge of electron injection and transport in the device in order to realize the high efficiency and long life characteristics required for commercialization. A form of a multi-layered structure with each characteristic and subdivided function, such as an organic layer, has been proposed. The introduction of a multi-layered structure improves the performance of organic EL devices to the commercialization characteristics, and is trying to expand its application range to portable information display devices and TV display devices, starting with radio display products for vehicles in 1997.

The demand for an increase in the size and resolution of a display places the problem of increasing the efficiency and longevity of organic EL devices. In particular, in the case of higher resolution realized through the formation of more pixels in the same area, it results in a reduction in the emission area of the organic EL pixels, which inevitably reduces the lifespan, and the most important technical problem that the organic EL device must overcome is Became.

In the organic EL device, when a current or voltage is applied to two electrodes, holes are injected into the organic material layer from the anode and electrons are injected into the organic material layer from the cathode. When the injected holes and electrons meet, excitons are formed, and these excitons fall to the ground state to emit light. In this case, the organic EL device may be classified into a fluorescent EL device in which singlet excitons contribute to light emission and a phosphorescent EL device in which triplet excitons contribute to light emission according to the type of electron spin of the formed excitons.

The electron spin of excitons, which is formed by recombination of electrons and holes, generates singlet excitons and triplet excitons at a rate of 25% and 75%. Fluorescent EL devices that emit light by singlet excitons theoretically cannot exceed 25% of the internal quantum efficiency depending on the generation rate, and 5% of the external quantum efficiency is accepted as a limit. Phosphorescent EL devices that emit light by triplet excitons improve luminous efficiency up to 4 times compared to fluorescence when a metal complex compound containing heavy atoms of transition metals such as Ir and Pt is used as a phosphorescent dopant. I can make it.

As described above, phosphorescent EL devices exhibit higher luminous efficiency than fluorescence in terms of luminous efficiency based on theoretical facts, but in blue phosphorescent devices excluding green and red, a phosphorescent dopant with deep blue color purity and high efficiency and a wide energy satisfying the same Blue phosphorescent devices have not yet been commercialized due to insufficient development level for Gap hosts, and blue phosphorescent devices are being used in products.

In order to improve the characteristics of the organic EL device described above, research results have been reported for increasing the stability of the device by preventing holes from diffusing into the electron transport layer. However, to date, satisfactory results have not been obtained.

The present invention was devised to solve the above-described problem, and by separately providing an organic functional layer in which a light emitting layer material and an electron transport auxiliary layer material are mixed in a predetermined ratio between the light emitting layer and the electron transport auxiliary layer, high efficiency, low voltage and long lifespan It is a technical problem to provide an organic EL device exhibiting at the same time.

In order to achieve the above technical problem, the present invention is a positive electrode; Hole transport area; Light-emitting layer; It has a structure in which an electron transport region and a cathode are sequentially stacked, and the electron transport region includes an electron transport auxiliary layer, an electron transport layer, and an electron injection layer, and is disposed between the light emitting layer and the electron transport auxiliary layer. Further comprising an organic functional layer, wherein the organic functional layer, the material of the light emitting layer; And a mixture of materials for the electron transport auxiliary layer.

In one embodiment of the present invention, the absolute value of the HOMO energy level of the electron transport auxiliary layer may be higher than the absolute value of the HOMO energy level of the emission layer.

In one embodiment of the present invention, a difference between the absolute value of the HOMO energy level of the electron transport auxiliary layer and the absolute value of the HOMO energy level of the emission layer may be greater than 0 eV and less than or equal to 1.5 eV.

In one embodiment of the present invention, the absolute value of the LUMO energy level of the electron transport auxiliary layer may be lower than the absolute value of the LUMO energy level of the electron transport layer and higher than the absolute value of the LUMO energy level of the light emitting layer.

In one embodiment of the present invention, a difference between the absolute value of the LUMO energy level of the electron transport auxiliary layer and the absolute value of the LUMO energy level of the electron transport layer may be greater than 0 eV and less than 1.0 eV.

In one embodiment of the present invention, a difference between the absolute value of the LUMO energy level of the electron transport auxiliary layer and the absolute value of the LUMO energy level of the emission layer may be in the range of 0 to 1.0 eV.

In one embodiment of the present invention, the organic functional layer is a material of the electron transport auxiliary layer; And it may be formed by co-deposition (co-deposition) the material of the light emitting layer.

In one embodiment of the present invention, the organic functional layer includes a material of the electron transport auxiliary layer, a host material and a dopant material contained in the light emitting layer, and the material of the electron transport auxiliary layer and the host material The mixing ratio is 5 to 95: 95 to 5 weight ratio, and the dopant material may be included in an amount of 0.5 to 30 parts by weight based on the total weight of the material of the electron transport auxiliary layer and the host material.

For one embodiment of the present invention, the hole transport region may include at least one of a hole injection layer, a hole transport layer, and a hole transport auxiliary layer.

In the present invention, an organic electroluminescent device having a low driving voltage and high luminous efficiency can be provided by arranging an organic functional layer in which these materials are mixed in a predetermined ratio between the light emitting layer and the electron transport auxiliary layer. In addition, by applying the organic electroluminescent device of the present invention to a display panel, it is possible to provide a display panel with improved performance and lifespan.

The effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the present specification.

1 is a cross-sectional view showing the structure of an organic electroluminescent device according to an embodiment of the present invention.
2 is a cross-sectional view showing the structure of an organic electroluminescent device according to another embodiment of the present invention.
FIG. 3 is a graph showing a relationship between a high occupied molecular orbital (HOMO) energy level between an emission layer and an electron transport auxiliary layer according to an embodiment of the present invention.
FIG. 4 is a graph showing a relationship between an LUMO (lowest unoccupied molecular orbital) energy level between a light emitting layer, an electron transport auxiliary layer, and an electron transport layer according to another embodiment of the present invention.
<Simple explanation of sign>
100, 200: organic electroluminescent element A, A': organic layer
10: anode 20: cathode
30: hole transport area 31: hole injection layer
32: hole transport layer 33: hole transport auxiliary layer
40: light emitting layer 50: electron transport region
51: electron transport layer 52: electron injection layer
53: electron transport auxiliary layer 60: organic functional layer

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms different from each other, and only these embodiments make the disclosure of the present invention complete, and common knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to those who have it, and the invention is only defined by the scope of the claims. Accordingly, in some embodiments, well-known process steps, well-known device structures, and well-known techniques have not been described in detail in order to avoid obscuring interpretation of the present invention. The same reference numerals refer to the same components throughout the specification.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used as meanings that can be commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not interpreted ideally or excessively unless explicitly defined specifically.

<Organic EL device>

An organic electroluminescent device according to an embodiment of the present invention includes: an anode; A negative electrode disposed opposite to the positive electrode; And one or more organic material layers interposed between the anode and the cathode and including a hole transport region, a light emitting layer, and an electron transport region, and between the light emitting layer and the electron transport auxiliary layer included in the electron transport region. The material of the mixture includes an organic functional layer mixed with each other.

This organic functional layer is in a state in which two adjacent organic material layers, that is, the material of the light emitting layer and the material of the electron transport auxiliary layer, are mixed and co-depositioned, so electron transport due to the barrier-free effect of the use of the same material. Electrons injected from the auxiliary layer can be smoothly supplied from the organic layer to the emission layer, thereby improving the luminous efficiency of the organic EL device and significantly improving the lifespan characteristics.

Hereinafter, preferred embodiments of the organic electroluminescent device according to the present invention will be described with reference to the accompanying drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

1 is a diagram showing the structure of an organic electroluminescent device according to an embodiment of the present invention.

Referring to FIG. 1, the organic electroluminescent device 100 includes an anode 10; A hole transport region 30; A light emitting layer 40; An electron transport region 50 and a cathode 20 are sequentially stacked, and the electron transport region 50 includes an electron transport auxiliary layer 53, an electron transport layer 51, and an electron injection layer 52. Including, and disposed between the light emitting layer 40 and the electron transport auxiliary layer 53, the material of the light emitting layer 40 and the material of the electron transport auxiliary layer 53 are mixed in a predetermined ratio, at least one It has a structure including an organic functional layer 60 of.

Here, the hole transport region 30 may include at least one of the hole transport layer 31 and the hole injection layer 32.

anode

In the organic electroluminescent device 100 according to the present invention, the anode 10 serves to inject holes into the organic material layer (A).

The material constituting the anode 10 is not particularly limited, and a conventional material known in the art may be used. Non-limiting examples thereof include metals such as vanadium, chromium, copper, zinc, and gold; Alloys thereof; Metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); Combinations of metals and oxides such as ZnO:Al and SnO ₂ :Sb; Conductive polymers such as polythiophene, poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxy)thiophene] (PEDT), polypyrrole, and polyaniline; And carbon black.

The method of manufacturing the positive electrode 10 is also not particularly limited, and may be manufactured according to a conventional method known in the art. For example, a method of coating an anode material on a substrate made of a silicon wafer, quartz, glass plate, metal plate, or plastic film may be mentioned.

cathode

In the organic electroluminescent device 100 according to the present invention, the cathode 20 serves to inject electrons into the organic material layer (A).

The material forming the negative electrode 20 is not particularly limited, and a conventional material known in the art may be used. Non-limiting examples thereof include metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead; Alloys thereof; And multi-layered materials such as LiF/Al and LiO ₂ /Al.

In addition, a method of manufacturing the negative electrode 20 is also not particularly limited, and may be manufactured according to a method known in the art.

Organic layer

The organic material layer (A) included in the organic electroluminescent device according to the present invention can be used without limitation in a conventional configuration used as an organic material layer of an existing organic EL device. For example, a hole transport region 30, a light emitting layer 40, and an electron It may include at least one selected from the group consisting of the transport region 50. In this case, when considering the characteristics of the organic electroluminescent device, it is preferable to include all of the aforementioned organic material layers.

Hole transport area

The hole transport region 30 included in the organic material layer A of the present invention serves to move holes injected from the anode 10 to the emission layer 40. The hole transport region 30 may include at least one selected from the group consisting of a hole injection layer 31 and a hole transport layer 32. In this case, when considering the characteristics of the organic electroluminescent device, it is preferable to include both the hole injection layer 31 and the hole transport layer 32 described above.

The material constituting the above-described hole injection layer 31 and the hole transport layer 32 is not particularly limited as long as it is a material having a low hole injection barrier and high hole mobility, and the hole injection layer/transport layer material used in the industry is not limited. Can be used. In this case, the material forming the hole injection layer 31 and the hole transport layer 32 may be the same or different from each other.

As the hole injection material, a hole injection material known in the art may be used without limitation. Non-limiting examples of usable hole injection materials include phthalocyanine compounds such as copper phthalocyanine; DNTPD (N,N'-diphenyl-N,N'-bis-[4-(phenyl-m-tolyl-amino)-phenyl]-biphenyl-4,4'-diamine), m-MTDATA(4,4' ,4"-tris(3-methylphenylphenylamino) triphenylamine), TDATA(4,4'4"-Tris(N,N-diphenylamino)triphenylamine), 2TNATA(4,4',4"-tris(N,-(2 -naphthyl)-N-phenylamino}-triphenylamine), PEDOT/PSS(Poly(3,4-ethylenedioxythiophene)/Poly(4-styrenesulfonate)), PANI/DBSA(Polyaniline/Dodecylbenzenesulfonic acid), PANI/CSA(Polyaniline/Camphor) sulfonicacid), PANI/PSS((Polyaniline)/Poly(4-styrenesulfonate)), etc. These can be used alone or in combination of two or more.

In addition, as the hole transport material, a hole transport material known in the art may be used without limitation. Non-limiting examples of usable hole transport materials include carbazole derivatives such as phenylcarbazole and polyvinylcarbazole, fluorene derivatives, TPD(N,N'-bis(3-methylphenyl)-N, Triphenylamine derivatives such as N'-diphenyl-[1,1-biphenyl]-4,4'-diamine), TCTA(4,4',4"-tris(N-carbazolyl)triphenylamine), NPB(N ,N'-di(1-naphthyl)-N,N'-diphenylbenzidine), TAPC(4,4'-Cyclohexylidene bis[N,N-bis(4-methylphenyl)benzenamine]), etc. These are used alone. Or, two or more types may be mixed.

The hole transport region 30 may be manufactured through a conventional method known in the art. For example, there are vacuum evaporation method, spin coating method, cast method, LB method (Langmuir-Blodgett), inkjet printing method, laser printing method, laser thermal imaging method (Laser Induced Thermal Imaging, LITI), and the like, but is not limited thereto.

Emitting layer

The light emitting layer 40 included in the organic material layer (A) of the present invention is a layer in which holes and electrons meet to form excitons, and the color of light emitted by the organic electroluminescent device according to the material forming the light emitting layer 40 is It can be different.

The light emitting layer 40 may include a host and a dopant, and the mixing ratio thereof may be appropriately adjusted within a range known in the art. For example, based on the total weight of the light emitting layer, the host in the range of 70 to 99.9% by weight and the dopant in the range of 0.1 to 30% by weight may be included. More specifically, when the emission layer 40 is blue fluorescence, green fluorescence, or red fluorescence, it may include 80 to 99.9% by weight of a host and 0.1 to 20% by weight of a dopant. In addition, when the emission layer 40 is blue fluorescence, green fluorescence, or red phosphorescence, it may include 70 to 99% by weight of a host and 1 to 30% by weight of a dopant.

The host included in the light emitting layer 40 of the present invention is not particularly limited as long as it is known in the art, and non-limiting examples thereof include an alkali metal complex; Alkaline earth metal complexes; Or condensed aromatic ring derivatives.

More specifically, as host materials, aluminum complexes, beryllium complexes, anthracene derivatives, pyrene derivatives, triphenylene derivatives, carbazole derivatives, dibenzofuran derivatives, and dibenzos that can increase the luminous efficiency and lifetime of organic electroluminescent devices. It is preferred to use a thiophene derivative, or a combination of one or more thereof.

In addition, the dopant included in the light-emitting layer 40 of the present invention is not particularly limited as long as it is known in the art, and non-limiting examples thereof include anthracene derivatives, pyrene derivatives, arylamine derivatives, iridium (Ir) or platinum (Pt ), and the like.

The dopant may be classified into a red dopant, a green dopant, and a blue dopant, and red dopants, green dopants and blue dopants commonly known in the art may be used without particular limitation.

Specifically, non-limiting examples of a red dopant include PtOEP (Pt(II) octaethylporphine: Pt(II) octaethylporphine), Ir(piq)3 (tris(2-phenylisoquinoline)iridium: tris(2-phenylisoquinoline) ) Iridium), Btp2Ir(acac) (bis(2-(2'-benzothienyl)-pyridinato-N,C3')iridium(acetylacetonate): bis(2-(2'-benzothienyl)-pyridinato-N , C3') iridium (acetylacetonate)), or a mixture of two or more thereof.

Further, non-limiting examples of the green dopant include Ir(ppy)3 (tris(2-phenylpyridine) iridium: tris(2-phenylpyridine) iridium), Ir(ppy)2(acac) (Bis(2-phenylpyridine)( Acetylacetonato)iridium(III): bis(2-phenylpyridine)(acetylaceto) iridium(III)), Ir(mppy)3 (tris(2-(4-tolyl)phenylpiridine)iridium: tris(2-(4- Tolyl)phenylpyridine) iridium), C545T (10-(2-benzothiazolyl)-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H,11H-[1]benzopyrano [6 ,7,8-ij]-quinolizin-11-one: 10-(2-benzothiazolyl)-1,1,7,7-tetramethyl-2,3,6,7,-tetrahydro-1H,5H ,11H-[1]benzopyrano [6,7,8-ij]-quinolizin-11-one), or mixtures of two or more thereof.

In addition, non-limiting examples of the blue dopant include F2Irpic (Bis[3,5-difluoro-2-(2-pyridyl)phenyl](picolinato)iridium(III): bis[3,5-difluoro-2-( 2-pyridyl)phenyl(picolinato) iridium(III)), (F2ppy)2Ir(tmd), Ir(dfppz)3, DPVBi (4,4'-bis(2,2'-diphenylethen-1-yl) )biphenyl: 4,4'-bis(2,2'-diphenylethen-1-yl)biphenyl), DPAVBi (4,4'-Bis[4-(diphenylamino)styryl]biphenyl: 4,4' -Bis(4-diphenylaminostyryl)biphenyl), TBPe (2,5,8,11-tetra-tert-butyl perylene: 2,5,8,11-tetra-tert-butyl perylene), or And mixtures of two or more of these.

The light emitting layer 40 according to the present invention includes a red light emitting layer comprising a red phosphorescent material; A green light-emitting layer comprising a green phosphorescent material; Alternatively, it may be a blue light-emitting layer including a blue phosphorescent material or a blue phosphorescent material. Preferably, it may be a light emitting layer including a green phosphorescent material.

The above-described light emitting layer 40 may be a single layer or may be formed of a plurality of layers of two or more layers. Here, when the emission layer 40 is a plurality of layers, the organic electroluminescent device may emit light of various colors. Specifically, the present invention can provide an organic electroluminescent device having a mixed color by providing a plurality of light emitting layers made of different materials in series. In addition, when a plurality of emission layers are included, the driving voltage of the device increases, while the current value in the organic electroluminescent device is constant, thereby providing an organic electroluminescent device having improved luminous efficiency by the number of emission layers.

Electron transport area

In the organic electroluminescent device 100 according to the present invention, the electron transport region 50 included in the organic material layer A serves to transfer electrons injected from the cathode 20 to the emission layer 40.

The electron transport region 50 may include at least one selected from the group consisting of the electron transport auxiliary layer 53, the electron transport layer 51, and the electron injection layer 52. At this time, in consideration of the characteristics of the organic electroluminescent device, it is preferable to include all of the electron transport auxiliary layer 53, the electron transport layer 51, and the electron injection layer 52 described above.

In the electron transport region 50 according to the present invention, the electron injection layer 52 may use an electron injection material having easy electron injection and high electron mobility without limitation. Non-limiting examples of the electron injection material that can be used include the above bipolar compounds, anthracene derivatives, heteroaromatic compounds, and alkali metal complex compounds. Specifically, LiF, Li ₂ O, BaO, NaCl, CsF; Lanthanum group metals such as Yb and the like; Alternatively, there are metal halides such as RbCl and RbI, and these may be used alone or in combination of two or more.

The electron transport region 50 according to the present invention, specifically, the electron transport layer 51 and/or the electron injection layer 52 may be co-deposited with an n-type dopant to facilitate injection of electrons from the cathode. At this time, as the n-type dopant, an alkali metal complex compound known in the art may be used without limitation, and examples thereof include an alkali metal, an alkaline earth metal, or a rare earth metal.

In addition, the electron transport auxiliary layer 53 may prevent excitons or holes generated in the light emitting layer 40 from diffusing into the electron transport region.

The electron transport auxiliary layer 53 serves to prevent holes from diffusing or moving to the electron transport layer 51, thereby improving the life of the organic EL device. That is, holes are blocked by the high energy barrier of the electron transport auxiliary layer 53 and diffuse to the electron transport layer 51 or cannot move and remain in the light emitting layer 40.

The electron transport auxiliary layer 53 may be made of a material having conventional electron transport characteristics known in the art without limitation. For example, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives (eg, BCP), heterocyclic derivatives containing nitrogen, and the like may be included.

In one embodiment according to the present invention, the compound (material) constituting the electron transport auxiliary layer 53 includes a six-membered moiety represented by the following formula (1); A 5-membered moiety represented by the following formula (2); And at least one electron withdrawing (EWG) moiety among polycyclic moieties in which the six-membered moiety and the five-membered moiety are condensed.

In Formula 1 or 2,

X ₁ to X ₆ and Y ₁ to Y ₅ are the same as or different from each other, and each independently N or C(R), provided that at least one of the X ₁ to X ₆ and Y ₁ to Y ₅ is N,

In the case of a plurality of C(R), a plurality of Rs are the same or different from each other, and each independently hydrogen, deuterium, halogen group, cyano group, nitro group, amino group, C ₁ to C ₄₀ alkyl group, C ₂ to C ₄₀ alkenyl group, C ₂ to C ₄₀ alkynyl group, C ₃ to C ₄₀ cycloalkyl group, heterocycloalkyl group of 3 to 40 nuclear atoms, C ₆ to C ₆₀ aryl group, 5 to 60 nuclear atoms Heteroaryl group, C ₁ ~ C ₄₀ alkyloxy group, C ₆ ~ C ₆₀ aryloxy group, C ₁ ~ C ₄₀ alkylsilyl group, C ₆ ~ C ₆₀ arylsilyl group, C ₁ ~ C ₄₀ alkyl boron group, C ₆ ~ C group ₆₀ arylboronic of, C ₆ ~ C ₆₀ aryl phosphine group, C ₆ ~ C aryl phosphine oxide ₆₀ group and a C ₆ ~ selected from the group consisting of an aryl amine of the C ₆₀ or , Or they may be combined with adjacent groups to form a condensed ring,

The alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, aryloxy group, alkyloxy group, cycloalkyl group, heterocycloalkyl group, arylamine group, alkylsilyl group, alkylborone group, arylborone group, aryl of R The phosphine group, the arylphosphine oxide group, and the arylamine group are each independently hydrogen, deuterium (D), halogen, cyano group, nitro group, C ₁ to C ₄₀ alkyl group, C ₂ to C ₄₀ alkenyl group, C ₂ to C ₄₀ alkynyl group, C ₃ to C ₄₀ cycloalkyl group, 3 to 40 nuclear atoms heterocycloalkyl group, C ₆ to C ₆₀ aryl group, 5 to 60 nuclear atoms heteroaryl group, C ₁ ~ C ₄₀ alkyloxy group, C ₆ ~ C ₆₀ aryloxy group, C ₁ ~ C ₄₀ alkylsilyl group, C ₆ ~ C ₆₀ arylsilyl group, C ₁ ~ C ₄₀ alkyl boron group, C ₆ - an aryl boronic of C _60, C ₆ ~ C ₆₀ aryl phosphine group, C ₆ ~ C aryl phosphine oxide ₆₀ group and a C ₆ ~ C ₆₀ aryl optionally substituted with 1 substituent at least one selected from the group consisting of amine groups of In this case, when the substituents are plural, they may be the same as or different from each other.

The compound constituting the electron transport auxiliary layer 53 (e.g., an electron transport auxiliary layer material) contains at least one nitrogen-containing heteroaromatic ring containing at least one nitrogen (N), that is, an electron withdrawing group (EWG). As a result, excellent electronic characteristics are exhibited. Accordingly, when a compound having a 6-membered or 5-membered moiety represented by Formulas 1 to 2 or a polycyclic moiety in which they are condensed is applied as a material of the electron transport auxiliary layer 53, electrons are removed from the cathode 20. Since it can be well received, electrons can be smoothly transferred to the light emitting layer 40, thereby lowering the driving voltage of the device 100 and inducing high efficiency and long life.

In addition, the material of the electron transport auxiliary layer 53 not only has a high triplet energy, but also the molecular weight of the compound is significantly increased through the control of various types of substituents introduced into the parent nucleus and the position of introduction, resulting in improved glass transition ionicity and high Can have thermal stability. In addition, since it is also effective in suppressing crystallization of the organic material layer, the organic electroluminescent device 100 including the same can greatly improve durability and lifespan characteristics.

According to an embodiment of the present invention, the electron withdrawing (EWG) moiety included in the compound constituting the electron transport auxiliary layer 53 may be further specified by any one selected from the following structural formula group. However, it is not particularly limited thereto.

In the above formula,

* Means a part where bonding with the compound constituting the auxiliary electron transport layer is formed.

Although not specifically indicated in the above structural formula, at least one or more substituents known in the art (eg, the same as the definition of R) may be substituted.

In one embodiment according to the present invention, the compound constituting the electron transport auxiliary layer 53 (e.g., an electron transport auxiliary layer material) is different from the electron attracting device (EWG), and the electron attracting device (EWG ) It may contain at least one conventional electron donor (EDG) moiety known in the art having higher electron donation. The compound constituting the electron transport auxiliary layer 53 having an electron withdrawing group (EWG) moiety and an electron donor (EDG) moiety at the same time may be a conventional bipolar compound in the art.

The electron donor (EDG) moiety may be embodied as any one selected from the group of substituents represented by the following structural formula, but is not particularly limited thereto.

In the above formula,

* Means a part in which a bond with a compound constituting the electron transport auxiliary layer is formed,

Z ₁ to Z ₃ are the same as or different from each other, and each independently selected from the group consisting of NR ₃ , O, S, and CR ₄ R ₅ ,

R ₁ to R ₅ are the same as or different from each other, and each independently hydrogen, deuterium, halogen group, cyano group, nitro group, amino group, C ₁ to C ₄₀ alkyl group, C ₂ to C ₄₀ alkenyl group, C ₂ ~ C ₄₀ alkynyl group, C ₃ ~ C ₄₀ cycloalkyl group, 3 to 40 nuclear atoms heterocycloalkyl group, C ₆ ~ C ₆₀ aryl group, 5 to 60 nuclear atoms heteroaryl group, C ₁ ~ C ₄₀ alkyloxy group, C ₆ ~ C ₆₀ aryloxy group, C ₁ ~ C ₄₀ alkylsilyl group, C ₆ ~ C ₆₀ arylsilyl group, C ₁ ~ C ₄₀ alkyl boron group, C ₆ ~ an aryl boronic of C _60, C ₆ ~ C ₆₀ aryl phosphine group, C ₆ ~ C ₆₀ aryl phosphine oxide group, and a C ₆ ~, or selected from the group consisting of an aryl amine of the C ₆₀ in, or they combine adjacent tile Can form a condensed ring;

m and n are each independently an integer of 0 to 4,

The alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, aryloxy group, alkyloxy group, cycloalkyl group, heterocycloalkyl group, arylamine group, alkylsilyl group, alkyl boron group, aryl of the R ₁ to R ₅ A boron group, a phosphine group, a phosphine oxide group, and an arylamine group are each independently hydrogen, deuterium (D), halogen, cyano group, nitro group, C ₁ to C ₄₀ alkyl group, C ₂ to C ₄₀ alkenyl group , C ₂ to C ₄₀ alkynyl group, C ₃ to C ₄₀ cycloalkyl group, heterocycloalkyl group having 3 to 40 nuclear atoms, C ₆ to C ₆₀ aryl group, heteroaryl group having 5 to 60 nuclear atoms, C ₁ ~ C ₄₀ alkyloxy group, C ₆ ~ C ₆₀ aryloxy group, C ₁ ~ C ₄₀ alkylsilyl group, C ₆ ~ C ₆₀ arylsilyl group, C ₁ ~ C ₄₀ alkyl boron group, arylboronic group of _{C 6 ~ C 60, C 6} ~ C 60 of the aryl phosphine group, C ₆ ~ C ₆₀ aryl phosphine oxide group and one substituent at least one selected from the group consisting of an aryl amine of the C ₆ ~ C ₆₀ of They may be substituted, and in this case, when the substituents are plural, they may be the same as or different from each other.

Although not specifically indicated in the above structural formula, at least one or more substituents known in the art (eg, the same as the definition of R) may be substituted.

The electron transport region 50 may be manufactured through a conventional method known in the art. For example, there are vacuum evaporation method, spin coating method, cast method, LB method (Langmuir-Blodgett), inkjet printing method, laser printing method, laser thermal imaging method (Laser Induced Thermal Imaging, LITI), and the like, but is not limited thereto.

Organic functional layer

The organic functional layer 60 included in the organic material layer (A) according to the present invention is an organic layer that is additionally inserted between the light emitting layer 40 and the electron transport auxiliary layer 53.

The organic functional layer 60 is an organic layer in which two adjacent organic material layers, that is, the material of the light emitting layer 40 and the material of the electron transport auxiliary layer 53, are mixed with each other to be co-depositioned. Since the organic functional layer 60 uses the same material as the material of the organic layer adjacent to each other, it exhibits a barrier-free effect of lowering the barrier between adjacent organic material layers, and thus the electrons injected from the auxiliary electron transport layer 53 are used. (electron) can be smoothly supplied from the organic layer (A) to the emission layer 40. Accordingly, since the possibility of forming excitons by meeting holes and electrons in the emission layer 40 increases, the luminous efficiency of the organic electroluminescent device can be improved and lifespan characteristics can be significantly improved.

In order for the organic functional layer 60 according to the present invention to smoothly exhibit the barrier-free effect described above, adjacent organic material layers, such as the light-emitting layer 40, the electron transport auxiliary layer 53, and the electron transport layer 51 There is a need to adjust the physical properties between materials as follows.

In one embodiment of the present invention, the absolute value of the HOMO (highest occupied molecular orbital) energy level of the electron transport auxiliary layer 53 may be higher than the absolute value of the HOMO energy level of the light emitting layer 40 ( See Figure 3 below). Here, the emission layer 40 may refer to a host.

Specifically, the difference between the absolute value of the HOMO energy level of the electron transport auxiliary layer 53 and the absolute value of the HOMO energy level of the light emitting layer 40 may be greater than 0 eV and less than 1.5 eV, and more specifically 0 It may be greater than eV and less than 1.0 eV. When the above-described HOMO energy level difference is satisfied, the electron transport auxiliary layer 53 forms an energy barrier, so that holes existing in the light emitting layer 40 diffuse to the electron transport auxiliary layer 53 or It does not move and stays in the light emitting layer 40. Accordingly, the possibility of forming excitons by meeting holes and electrons in the emission layer 40 is increased, thereby improving the luminous efficiency of the organic electroluminescent device 100 and significantly improving the lifetime characteristics.

In another embodiment of the present invention, the LUMO (lowest unoccupied molecular orbital) energy level of the electron transport auxiliary layer 53 is two adjacent organic material layers, specifically the emission layer 40, the electron transport layer 51 and the emission layer. (40) to exist between. For example, the absolute value of the LUMO energy level of the electron transport auxiliary layer 53 is lower than the absolute value of the LUMO energy level of the electron transport layer 51 and higher than the absolute value of the LUMO energy level of the light emitting layer 40 Can (see Fig. 4 below).

Specifically, a difference between the LUMO energy level of the electron transport auxiliary layer 53 and the LUMO energy level of the electron transport layer 51 may be greater than 0 eV and less than 1.0 eV. In addition, the difference between the LUMO energy level value of the electron transport auxiliary layer 53 and the absolute value of the LUMO energy level of the emission layer 40 may be in the range of 0 to 1.0 eV, and more specifically greater than 0 eV, 1.0 It may be less than or equal to eV. When the above-described LUMO energy level difference is satisfied, the LUMO energy levels of the light emitting layer 40, the electron transport auxiliary layer 53, and the electron transport layer 51 are arranged in a stepwise manner (see FIG. 4 below). When the stepwise LUMO energy level is satisfied, electrons transferred through the cathode 20 may be more smoothly transferred to the light emitting layer 40 through the stepwise arrangement of each layer.

In one embodiment of the present invention, the organic functional layer 60 may be manufactured according to a method known in the art by using the material of the light emitting layer 40 and the material of the electron transport auxiliary layer 53. For example, it may be formed by co-depositioning a material of the light emitting layer 40 and a material of the electron transport auxiliary layer 53 at a predetermined ratio.

The organic functional layer 60 is not particularly limited as long as it includes the material of the light emitting layer 40 and the material of the electron transport auxiliary layer 53, as long as the components, structure, thickness, etc. of the organic functional layer 60 are included. For example, the organic functional layer 60 is a single layer formed by co-depositing a material of the light-emitting layer 40 and a material of the electron transport auxiliary layer 53, or the material of the light-emitting layer 40 and the auxiliary layer 53 ) A mixture of materials; and at least one heterogeneous material may be a mixture of a mono-layer. Alternatively, it may have a multi-layer structure in which two or more different materials are stacked by forming separate layers, respectively.

Specifically, the organic functional layer 60 is an electron transport auxiliary layer 53 material containing at least one or more 6-membered moieties, 5-membered moieties, or condensed polycyclic moieties represented by Chemical Formulas 1 to 2. It includes a host material and a dopant material contained in the emission layer 40. At this time, the mixing ratio of the material of the electron transport auxiliary layer 53 and the host material is not particularly limited, for example, 5 to 95: 95 to 5 weight ratio, specifically 5 to 90: 95 to 10 weight ratio I can.

In addition, the content of the dopant material may be appropriately adjusted within a conventional range known in the art. For example, the dopant may be included in an amount of 0.5 to 30 parts by weight based on the total weight (eg, 100 parts by weight) of the electron transport auxiliary layer 53 material and the host material, but is not particularly limited thereto.

Light-emitting auxiliary layer

Optionally, the organic light-emitting device 100 of the present invention may further include a light-emitting auxiliary layer (not shown) disposed between the hole transport region 30 and the light-emitting layer 40.

The light-emitting auxiliary layer serves to transport the holes moved from the hole transport region 30 to the light-emitting layer 40 and controls the thickness of the organic material layer (A). This light-emitting auxiliary layer has a high LUMO value to prevent electrons from moving to the hole transport layer 32, and has a high triplet energy to prevent excitons of the light-emitting layer 40 from diffusing to the hole transport layer 32.

This light emission auxiliary layer may include a hole transport material, and may be made of the same material as the hole transport region. Further, the auxiliary light emitting layers of the red, green, and blue organic light emitting devices may be made of the same material.

The material for the light-emitting auxiliary layer is not particularly limited, and examples thereof include carbazole derivatives or arylamine derivatives. Non-limiting examples of the light emission auxiliary layer that can be used include NPD (N, N-dinaphthyl-N, N'-diphenyl benzidine), TPD (N, N'-bis-(3-methylphenyl)-N, N'-bis ( phenyl)-benzidine), s-TAD, MTDATA(4, 4', 4″-Tris(N-3-methylphenyl-Nphenyl-amino)-triphenylamine). These may be used alone or in combination of two or more. In addition, the light emission auxiliary layer may include a p-type dopant in addition to the above-described material. As the p-type dopant, a known p-type dopant used in the art may be used.

Capping layer

Optionally, the organic electroluminescent device 100 of the present invention may further include a capping layer (not shown) disposed on the above-described cathode 20. The capping layer serves to protect the organic light emitting device and help light generated from the organic material layer to be efficiently emitted to the outside.

The capping layer is tris-8-hydroxyquinoline aluminum (Alq3), ZnSe, 2,5-bis(6′- (2′,2″-bipyridyl))-1,1-dimethyl-3,4-diphenylsilole, 4′-bis[N-(1-napthyl)-N-phenyl-amion] biphenyl (α-NPD), N,N′-diphenyl-N,N′-bis(3-methylphenyl) -1,1′- It may contain at least one selected from the group consisting of biphenyl-4,4'-diamine (TPD), 1,1'-bis(di-4-tolylaminophenyl) cyclohexane (TAPC). The material forming the capping layer is inexpensive compared to materials of other layers of the organic light emitting device.

Such a capping layer may be a single layer, but may include two or more layers having different refractive indices, so that the refractive index gradually changes while passing through the two or more layers.

The capping layer may be manufactured by a conventional method known in the art, and for example, various methods such as a vacuum deposition method, a spin coating method, a cast method, or a Langmuir-Blodgett (LB) method may be used.

The organic light emitting device 100 of the present invention including the above-described configuration may be manufactured according to a conventional method known in the art. For example, after vacuum depositing an anode material on a substrate, an organic light-emitting device may be manufactured by vacuum-depositing a material of a hole transport region material, an emission layer material, an electron transport region material, and a cathode material on the anode in order .

2 is a diagram illustrating a structure of an organic electroluminescent device according to another embodiment of the present invention.

Referring to FIG. 2, the organic electroluminescent device 200 includes an anode 10; A hole transport region 30; A light emitting layer 40; An electron transport region 50 and a cathode 20 are sequentially stacked, and the electron transport region 50 includes an electron transport auxiliary layer 53, an electron transport layer 51, and an electron injection layer 52. And at least one organic functional layer disposed between the emission layer 40 and the electron transport auxiliary layer 53, and in which materials of the emission layer 40 and the electron transport auxiliary layer 53 are mixed in a predetermined ratio It has a structure containing 60.

Here, the hole transport region 30 may include at least one of a hole injection layer 31, a hole transport layer 32, and a hole transport auxiliary layer 33, preferably a hole injection layer 31, a hole transport layer It includes both (32) and the hole transport auxiliary layer (33).

The hole transport auxiliary layer 33 is not particularly limited as long as it is a material having a low hole injection barrier and high hole mobility, and a material known in the art may be used without limitation. As an example, it may include a carbazole derivative, a fluorene derivative, a triphenylamine derivative, and the like.

The hole transport auxiliary layer 33 is a vacuum deposition method, a spin coating method, a cast method, an LB method (Langmuir-Blodgett), an inkjet printing method, a laser printing method, a laser induced thermal method, as known in the art. Imaging, LITI) or the like, but is not limited thereto.

Meanwhile, each of the components 10, 20, 30-32, 40, and 51-53 of the organic electroluminescent device illustrated in FIG. 2 is the same as that of FIG. 1, and thus individual descriptions thereof will be omitted.

The organic electroluminescent devices 100 and 200 according to the present invention have a structure in which an anode 10, an organic material layer (A, A'), and a cathode 20 are sequentially stacked, but the anode 10 and the organic material layer (A, A') or between the cathode 20 and the organic material layers (A, A') may further include an insulating layer or an adhesive layer. The organic electroluminescent device according to the present invention may have excellent lifespan characteristics because, when voltage, current, or both are applied, the life time of initial brightness is increased while maintaining maximum luminous efficiency.

Hereinafter, the present invention will be described in detail through examples, but the following examples are only illustrative of the present invention, and the present invention is not limited by the following examples.

[Preparation Example] Compounds 1 to 20

The compounds of the present invention were prepared as follows, and their HOMO, LUMO, and triplet energies were measured by methods known in the art, respectively, and are shown in Table 1 below. In addition, ADN compound and Alq ₃ compound were used as controls.

1) HOMO energy level was measured by CV (cyclic voltammetry) method.

2) As for the LUMO energy level, the bandgap energy of each compound was obtained from the UV spectrum, and then the LUMO energy level was calculated as the difference between the bandgap energy and the HOMO energy level.

3) The triplet energy was measured with a phosphorescence spectrum at 77K, and measured with a QuantaMaster 30 Spectrofluorometer (PTI). A sample was prepared by dissolving a sample at a concentration of 10 ^-4 M in 2-methylTHF solvent, and then, a phosphorescence spectrum was measured at a low temperature of 77 K using liquid nitrogen.

compound HOMO (eV) LUMO (eV) One 5.97 2.67 2 5.82 2.67 3 5.84 2.71 4 5.83 2.64 5 6.02 2.62 6 5.82 2.67 7 6.25 2.75 8 5.85 2.76 9 6.22 2.65 10 5.78 2.71 11 5.76 2.75 12 5.74 2.85 13 5.98 2.77 14 6.05 2.67 ADN 5.80 2.62 Alq ₃ 5.62 2.80

[Examples 1 to 14] Fabrication of a blue organic electroluminescent device

After the compound prepared in Preparation Example was subjected to high-purity sublimation purification by a commonly known method, a blue organic electroluminescent device was manufactured according to the following procedure.

First, the glass substrate coated with ITO (Indium tin oxide) to a thickness of 1500 Å was washed with distilled water and ultrasonic waves. After washing with distilled water, ultrasonically clean with a solvent such as isopropyl alcohol, acetone, methanol, etc., dry, transfer to a UV OZONE cleaner (Power Sonic 405, Hwashin Tech), and clean the substrate for 5 minutes using UV And transferred the substrate to a vacuum evaporator.

On the ITO transparent electrode prepared as above, DS-205 (Doosan Electronics 80 nm)/NPB (15 nm)/ADN + 5% DS-405 (Doosan Electronics, 25nm)/ ADN + 5% DS-405 + Table The compound of 2 (Doosan Electronics, 5nm) / compound of Table 2 (5 nm) / Alq3 (25 nm) / LiF (1 nm) / Al (200 nm) were stacked in order to prepare an organic electroluminescent device (following See Table 2).

compound Thickness (nm) Hole injection layer DS-205 80 Hole transport layer NPB 15 Emitting layer ADN + 5% DS-405 25 Organic functional layer ADN + 5% DS-405 + compounds of Table 1 5 Electron transport auxiliary layer Compounds of Table 1 5 Electron transport layer Alq ₃ 25 Electron injection layer LiF One cathode Al 200

[Comparative Example 1] Preparation of blue organic electroluminescent device

A blue organic electroluminescent device of Comparative Example 1 was manufactured in the same manner as in Example 1, except that the organic functional layer was not used and the emission layer was deposited at 30 nm.

[Comparative Example 2] Preparation of blue organic electroluminescent device

The blue organic electric field of Comparative Example 2 was carried out in the same manner as in Example 1, except that an electron transport auxiliary layer (eg Compound 1) and a compound different from the light emitting layer material (eg Compound 5) were used as organic functional layer components A light-emitting device was fabricated.

For reference, the structures of NPB, ADN and Alq ₃ used in Examples 1 to 14 and Comparative Example 1 are as follows, respectively.

[Evaluation Example 1]

For the organic electroluminescent devices prepared in Examples 1 to 14 and Comparative Examples 1 to 2, respectively, the driving voltage, emission wavelength, and current efficiency at a current density of 10 mA/cm 2 were measured, and the results are shown in Table 3 below. Done.

Sample Electronic transport
Auxiliary layer material
(a) Organic functional layer Driving voltage
(V) Emission peak
(nm) Current efficiency
(cd/A) a' Weight ratio
(a': ADN: DS-405) Example 1 One One 50: 50: 5 4.2 456 7.8 Example 2 2 2 50: 50: 5 4.1 452 7.4 Example 3 3 3 50: 50: 5 4.1 450 8.0 Example 4 4 4 50: 50: 5 3.8 452 7.6 Example 5 5 5 50: 50: 5 3.7 455 7.4 Example 6 6 6 50: 50: 5 4.0 452 8.2 Example 7 7 7 50: 50: 5 4.0 455 8.1 Example 8 8 8 50: 50: 5 3.9 455 7.8 Example 9 9 9 50: 50: 5 4.1 452 7.6 Example 10 10 10 50: 50: 5 4.1 455 7.7 Example 11 11 11 50: 50: 5 3.7 455 8.2 Example 12 12 12 50: 50: 5 3.7 458 7.1 Example 13 13 13 50: 50: 5 3.8 455 7.8 Example 14 14 14 50: 50: 5 4.2 456 8.0 Comparative Example 1 - - - 4.8 458 6.2 Comparative Example 2 One 5 50: 50: 5 4.6 458 6.7

As shown in Table 3, the blue organic electroluminescent devices of Examples 1 to 14 including organic functional layers in which materials of the light emitting layer and the electron transport auxiliary layer are mixed according to the present invention are compared without the organic functional layer The blue organic electroluminescent device of Example 1; And compared with the organic electroluminescent device of Comparative Example 2 in which different materials were used for the electron transport auxiliary layer and the organic functional layer, it was found that excellent performance was exhibited in terms of current efficiency, emission peak, and driving voltage.

Claims (12)

anode; Hole transport area; Light-emitting layer; It has a structure in which an electron transport region and a cathode are sequentially stacked,
The electron transport region includes an electron transport auxiliary layer, an electron transport layer, and an electron injection layer,
Further comprising at least one organic functional layer disposed between the emission layer and the electron transport auxiliary layer,
The organic functional layer may include a material for the emission layer; And a mixture of materials for the electron transport auxiliary layer. The method of claim 1,
An organic electroluminescent device, wherein the absolute value of the HOMO energy level of the electron transport auxiliary layer is higher than the absolute value of the HOMO energy level of the emission layer. The method of claim 2,
The organic electroluminescent device, wherein a difference between the absolute value of the HOMO energy level of the electron transport auxiliary layer and the absolute value of the HOMO energy level of the light emitting layer is greater than 0 eV and less than 1.5 eV. The method of claim 1,
The absolute value of the LUMO energy level of the electron transport auxiliary layer is lower than the absolute value of the LUMO energy level of the electron transport layer, and higher than the absolute value of the LUMO energy level of the emission layer. The method of claim 4,
An organic electroluminescent device, wherein a difference between the absolute value of the LUMO energy level of the electron transport auxiliary layer and the absolute value of the LUMO energy level of the electron transport layer is greater than 0 eV and less than 1.0 eV. The method of claim 4,
The organic electroluminescent device, wherein a difference between the absolute value of the LUMO energy level of the electron transport auxiliary layer and the absolute value of the LUMO energy level of the light emitting layer is 0 to 1.0 eV. The method of claim 1,
The compound constituting the electron transport auxiliary layer includes a six-membered moiety represented by the following formula (1); A 5-membered moiety represented by the following formula (2); And at least one electron withdrawing (EWG) moiety among the polycyclic moieties in which the six-membered moiety and the five-membered moiety are condensed:
[Formula 1]

[Formula 2]

In Formula 1 or 2,
X ₁ to X ₆ and Y ₁ to Y ₅ are the same as or different from each other, and each independently N or C(R), provided that at least one of the X ₁ to X ₆ and Y ₁ to Y ₅ is N,
In the case of a plurality of C(R), a plurality of Rs are the same or different from each other, and each independently hydrogen, deuterium, halogen group, cyano group, nitro group, amino group, C ₁ to C ₄₀ alkyl group, C ₂ to C ₄₀ alkenyl group, C ₂ to C ₄₀ alkynyl group, C ₃ to C ₄₀ cycloalkyl group, heterocycloalkyl group of 3 to 40 nuclear atoms, C ₆ to C ₆₀ aryl group, 5 to 60 nuclear atoms Heteroaryl group, C ₁ ~ C ₄₀ alkyloxy group, C ₆ ~ C ₆₀ aryloxy group, C ₁ ~ C ₄₀ alkylsilyl group, C ₆ ~ C ₆₀ arylsilyl group, C ₁ ~ C ₄₀ alkyl boron group, C ₆ ~ C group ₆₀ arylboronic of, C ₆ ~ C ₆₀ aryl phosphine group, C ₆ ~ C aryl phosphine oxide ₆₀ group and a C ₆ ~ selected from the group consisting of an aryl amine of the C ₆₀ or , Or they may be combined with adjacent groups to form a condensed ring,
The alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, aryloxy group, alkyloxy group, cycloalkyl group, heterocycloalkyl group, arylamine group, alkylsilyl group, alkylborone group, arylborone group, aryl of R The phosphine group, the arylphosphine oxide group, and the arylamine group are each independently hydrogen, deuterium (D), halogen, cyano group, nitro group, C ₁ to C ₄₀ alkyl group, C ₂ to C ₄₀ alkenyl group, C ₂ to C ₄₀ alkynyl group, C ₃ to C ₄₀ cycloalkyl group, 3 to 40 nuclear atoms heterocycloalkyl group, C ₆ to C ₆₀ aryl group, 5 to 60 nuclear atoms heteroaryl group, C ₁ ~ C ₄₀ alkyloxy group, C ₆ ~ C ₆₀ aryloxy group, C ₁ ~ C ₄₀ alkylsilyl group, C ₆ ~ C ₆₀ arylsilyl group, C ₁ ~ C ₄₀ alkyl boron group, C ₆ - an aryl boronic of C _60, C ₆ ~ C ₆₀ aryl phosphine group, C ₆ ~ C aryl phosphine oxide ₆₀ group and a C ₆ ~ C ₆₀ aryl optionally substituted with 1 substituent at least one selected from the group consisting of amine groups of In this case, when the substituents are plural, they may be the same as or different from each other. The method of claim 7,
The electron attracting (EWG) moiety is an organic electroluminescent device selected from the following structural formula.

The method of claim 7,
The compound constituting the electron transport auxiliary layer is different from the electron attracting (EWG) and includes at least one moiety selected from the group of substituents represented by the following structural formula:

In the above formula,
Z ₁ to Z ₃ are the same as or different from each other, and each independently selected from the group consisting of NR ₃ , O, S, and CR ₄ R ₅ ,
R ₁ to R ₅ are the same as or different from each other, and each independently hydrogen, deuterium, halogen group, cyano group, nitro group, amino group, C ₁ to C ₄₀ alkyl group, C ₂ to C ₄₀ alkenyl group, C ₂ ~ C ₄₀ alkynyl group, C ₃ ~ C ₄₀ cycloalkyl group, 3 to 40 nuclear atoms heterocycloalkyl group, C ₆ ~ C ₆₀ aryl group, 5 to 60 nuclear atoms heteroaryl group, C ₁ ~ C ₄₀ alkyloxy group, C ₆ ~ C ₆₀ aryloxy group, C ₁ ~ C ₄₀ alkylsilyl group, C ₆ ~ C ₆₀ arylsilyl group, C ₁ ~ C ₄₀ alkyl boron group, C ₆ ~ aryl of C ₆₀ boron group, C ₆ ~ C ₆₀ aryl phosphine group, C ₆ ~ C aryl phosphine oxide ₆₀ group and a C ₆ ~, or selected from the group consisting of an aryl amine of the C _60, or adjacent groups bonded to the condensation of Can form a ring;
m and n are each independently an integer of 0 to 4,
The alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, aryloxy group, alkyloxy group, cycloalkyl group, heterocycloalkyl group, arylamine group, alkylsilyl group, alkyl boron group, aryl of the R ₁ to R ₅ A boron group, a phosphine group, a phosphine oxide group, and an arylamine group are each independently hydrogen, deuterium (D), halogen, cyano group, nitro group, C ₁ to C ₄₀ alkyl group, C ₂ to C ₄₀ alkenyl group , C ₂ to C ₄₀ alkynyl group, C ₃ to C ₄₀ cycloalkyl group, heterocycloalkyl group having 3 to 40 nuclear atoms, C ₆ to C ₆₀ aryl group, heteroaryl group having 5 to 60 nuclear atoms, C ₁ ~ C ₄₀ alkyloxy group, C ₆ ~ C ₆₀ aryloxy group, C ₁ ~ C ₄₀ alkylsilyl group, C ₆ ~ C ₆₀ arylsilyl group, C ₁ ~ C ₄₀ alkyl boron group, arylboronic group of _{C 6 ~ C 60, C 6} ~ C 60 of the aryl phosphine group, C ₆ ~ C ₆₀ aryl phosphine oxide group and one substituent at least one selected from the group consisting of an aryl amine of the C ₆ ~ C ₆₀ of It may be substituted, and in this case, when the substituents are plural, they may be the same or different from each other. The method of claim 1,
The organic functional layer is a material of the electron transport auxiliary layer; And an organic electroluminescent device formed by co-depositing a material for the emission layer. The method of claim 10,
The organic functional layer includes a material of the electron transport auxiliary layer, a host material and a dopant material contained in the light emitting layer,
The mixing ratio of the material of the electron transport auxiliary layer and the host material is 5 to 95: 95 to 5 weight ratio,
The dopant material is included in an amount of 0.5 to 30 parts by weight based on the total weight of the material of the electron transport auxiliary layer and the host material. The method of claim 1,
The hole transport region is an organic electroluminescent device including at least one of a hole injection layer, a hole transport layer, and a hole transport auxiliary layer.

Images