CN114141963A

CN114141963A - Organic electroluminescent device containing asymmetric triarylamine and application thereof

Info

Publication number: CN114141963A
Application number: CN202010925819.4A
Authority: CN
Inventors: 张小庆; 唐丹丹; 李崇; 崔明
Original assignee: Jiangsu Sunera Technology Co Ltd
Current assignee: Jiangsu Sunera Technology Co Ltd
Priority date: 2020-09-04
Filing date: 2020-09-04
Publication date: 2022-03-04
Anticipated expiration: 2040-09-04
Also published as: CN114141963B

Abstract

The present invention relates to an organic electroluminescent (OLED) device, and more particularly, to an OLED device comprising an asymmetric triarylamine compound as a capping layer (CPL) and having significantly improved light extraction efficiency and significantly improved color shift effect of a screen.

Description

Organic electroluminescent device containing asymmetric triarylamine and application thereof

Technical Field

Background

Currently, the OLED display technology has been applied in the fields of smart phones, tablet computers, and the like, and will be further expanded to the large-size application fields of televisions and the like. Since there is a great gap between the external quantum efficiency and the internal quantum efficiency of the OLED, the development of the OLED is greatly restricted. Therefore, how to improve the light extraction efficiency of the OLED becomes a hot point of research. Total reflection occurs at the interface between the ITO thin film and the glass substrate and the interface between the glass substrate and the air, the light emitted to the space outside the OLED device accounts for about 20% of the total amount of the organic material thin film EL, and the remaining about 80% of the light is confined mainly in the organic material thin film, the ITO thin film, and the glass substrate in the form of guided waves. It can be seen that the light extraction efficiency of the conventional OLED device is low (about 20%), which severely restricts the development and application of the OLED. Therefore, it is of great interest to reduce the total reflection effect in OLED devices and to increase the ratio of light coupled into the external space in front of the device (light extraction efficiency).

Currently, an important method for improving the light extraction efficiency of OLEDs is to form structures such as folds, photonic crystals, microlens arrays (MLAs), and the addition of surface coatings on the light exit surface. The first two methods structurally affect the angular distribution of the radiation spectrum of the OLED, and the third method has a complex preparation process. The surface covering layer is simple in process, the luminous efficiency is improved by more than 30%, and people pay attention to the technology.

In recent years, in order to obtain high light extraction efficiency, organic electroluminescent devices comprising an azabenzene or a heteroaryl compound as a capping layer have been disclosed in the prior art. Although these materials have a certain effect of improving the light extraction efficiency, when they are applied to a device, a phenomenon of blackening or poor polarization of materials occurs, that is, the light emitting color and the light emitting intensity of the device are obviously different with the change of the test angle. In order to solve such problems, there is a continuous search for a cover material having higher performance.

Disclosure of Invention

The present invention is directed to provide an organic electroluminescent (OLED) device having an improved light extraction effect and an improved viewing angle effect, and preventing the occurrence of a black spot phenomenon.

In order to achieve the above object, the present invention provides an organic electroluminescent device comprising:

a substrate layer;

a first electrode over the substrate;

an organic light emitting functional layer over the first electrode;

a second electrode over the organic light emitting functional layer; and

a cover layer over the second electrode;

wherein the capping layer comprises an asymmetric triarylamine compound, represented by formula (I):

x is O, S, Se or N-R₆；

L represents a single bond, phenylene or biphenylene;

Ar₁represented by a structure represented by the general formula (2) or the general formula (3)

Y is represented by O, S or N-R₆；

Wherein R is₁、R₂、R₃、R₄、R₅Each independently is a hydrogen atom, C₆-C₃₀Aryl or C₂-C₃₀Heteroaryl group, wherein C₆-C₃₀Aryl or C₂-C₃₀Each heteroaryl is unsubstituted or substituted with one or more substituents selected from: protium atom, deuterium atom, tritium atom, (C)₁-C₆) Alkyl or (C)₁-C₆) An alkoxy group; or

R₁、R₂、R₃、R₄、R₅Any two adjacent of them can be combined together to form C₆-C₃₀Aryl or C₂-C₃₀Heteroaryl group, wherein C₆-C₃₀Aryl or C₂-C₃₀Each heteroaryl is unsubstituted or substituted with one or more substituents selected from: protium atom, deuterium atom, tritium atom, (C)₁-C₆) Alkyl or (C)₁-C₆) An alkoxy group;

R₆each occurrence, which is the same or different, isSingle bond, C₆-C₃₀Aryl or C₂-C₃₀Heteroaryl group, wherein C₆-C₃₀Aryl or C₂-C₃₀Heteroaryl is unsubstituted or substituted with one or more substituents selected from: protium atom, deuterium atom, tritium atom, (C)₁-C₆) Alkyl or (C)₁-C₆) An alkoxy group.

According to the OLED device of the invention, the asymmetric triarylamine compound as the covering layer material has a refractive index in the range of 2.0-2.3, preferably 2.15-2.30, under blue light with the wavelength of 450 nm; the refractive index range of the green light with the wavelength of 525nm is 2.09-2.15; a refractive index in the range of 1.95 to 2.09, preferably 1.97 to 2.09, under red light having a wavelength of 620 nm; and the difference between the refractive indices for blue and red light is 0.2-0.3, preferably 0.2-0.25; most preferably 0.2-0.22.

According to the OLED device, the asymmetric triarylamine compound used as the covering layer material has the evaporation temperature lower than the decomposition temperature, and the evaporation temperature is 270-380 ℃, preferably 300-375 ℃, and most preferably 355-369 ℃. The LUMO energy level is shallower than-2.8 eV, and (-2.6) - (-2.8) eV is preferable.

According to the OLED device of the present invention, the thickness of the capping layer is 10-1000nm, preferably 40-140nm, more preferably 50-90nm, most preferably 60-75 nm.

The object of the present invention is also achieved by providing a display including the above-described OLED device.

Advantageous effects

The compounds of the present invention are asymmetric triarylamine compounds characterized in that the three groups attached to the nitrogen atom of the tertiary amine are all different, specifically, three different aryl or heteroaryl groups. Based on the asymmetric structure, the compound has higher molecular thermal stability, the required temperature is lower when evaporation is carried out, and the evaporation temperature is lower than the decomposition temperature, so that the decomposition during evaporation is effectively avoided and the compound is suitable for long-time evaporation. In addition, the material has lower extinction coefficient, higher refractive index of visible light and proper difference value of refractive index under blue light and red light in the visible light field, so that when the material is used as a covering layer material to be applied to an OLED device, the light extraction efficiency of the device can be effectively improved, the polarization effect can be improved, and the black spot phenomenon can be avoided.

Drawings

FIG. 1 is a schematic cross-sectional view showing an example of application of the compound of the present invention (top-emitting organic electroluminescent device),

wherein 100 is a substrate, 200 is a first electrode, 300 is an organic light emitting functional layer, 400 is a second electrode, and 500 is a cover layer.

Fig. 2 is a schematic cross-sectional view of an organic light emitting functional layer 300 of the top emission organic electroluminescent device in fig. 1, wherein 310(HIL) is a hole injection layer, 320(HTL) is a hole transport layer, 330(EBL) is an electron blocking layer, 340(EML) is a light emitting layer, 350(HBL) is a hole blocking layer, 360(ETL) is an electron transport layer, and 370(EIL) is an electron injection layer.

Fig. 3 is a configuration of the light emitting layer 340: the organic light emitting diode is formed by composite light emitting material layers which are arranged together in the transverse direction, wherein EM1, EM2 and EM3 are a blue organic light emitting material layer, a green organic light emitting material layer and a red organic light emitting material layer respectively.

Fig. 4 shows a luminance decay spectrum of the white light device.

Fig. 5 shows color shift data for white light devices at different angles.

Detailed Description

Definition of

Throughout this specification, unless explicitly described to the contrary, any element "comprising" is to be understood as implying that it includes other elements but not excluding any other elements. Further, it will be understood that throughout the specification, when an element such as a layer, film, region, or substrate is referred to as being "on" or "over" another element, it can be "directly on" the other element, or intervening elements may also be present. In addition, "on … …" or "above … …" means above the target portion, and does not necessarily mean above in terms of the direction of gravity.

Herein, C₆-C₃₀Aryl refers to a monovalent group comprising a carbocyclic aromatic system having from 6 to 30 carbon atoms as ring-forming atoms. C₆-C₃₀Non-limiting examples of aryl groups can include phenyl, biphenyl, phenanthryl, terphenyl, naphthyl, and the like. When C is present₆-C₃₀When the aryl group includes two or more rings, the rings may be fused to each other.

Herein, C₂-C₃₀Heteroaryl means a monovalent group comprising a carbocyclic aromatic system having as ring-forming atoms at least one heteroatom selected from N, O, P and s and 2 to 30 carbon atoms. C_2-30Non-limiting examples of heteroaryl groups may include pyridyl, dibenzofuranyl, benzoxazolyl, dibenzoxazolyl, carbazolyl, N-phenylcarbazolyl, and the like. When C is present₂-C₃₀When the heteroaryl group includes two or more rings, the rings may be fused to each other.

Herein, (C)₁-C₆) Alkyl refers to a group of saturated aliphatic hydrocarbons having 1 to 6 carbon atoms and which may be branched or straight chain. (C)₁-C₆) Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, 1-methylbutyl, 2-methylbutyl, 1-ethylpropyl, 1, 2-dimethylpropyl, hexyl, and the like. Among these alkyl groups, (C) is particularly preferred₁-C₄) An alkyl group.

Herein, (C)₁-C₆) Alkoxy means an alkyl radical which is linked via an oxygen bridge and has 1 to 6 carbon atoms and may be branched or unbranched, (C)₁-C₆) Examples of alkoxy include, but are not limited to, methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, sec-butoxy, tert-butoxy, pentyloxy, 2-pentyloxy, isopentyloxy, neopentyloxy, hexyloxy, 2-hexyloxy, 3-methylpentyloxy, and the like.

In one embodiment of the present invention, the capping layer of the OLED device comprises an asymmetric triarylamine compound, represented by formula (1):

x is O, S, Se or N-R₆；

L represents a single bond, phenylene or biphenylene;

Y is represented by O, S, Se or N-R₆；

R₆each occurrence being the same or different and being a single bond, C₆-C₃₀Aryl or C₂-C₃₀Heteroaryl group, wherein C₆-C₃₀Aryl or C₂-C₃₀Heteroaryl is unsubstituted or substituted with one or more substituents selected from: protium atom, deuterium atom, tritium atom, (C)₁-C₆) Alkyl or (C)₁-C₆) An alkoxy group.

In a preferred embodiment, the covering layer of the OLED device comprises an asymmetric triarylamine compound of formula (1), wherein,

x is represented by O, S or N-R₆；

L represents a single bond, phenylene or biphenylene;

Y is represented by O, S or N-R₆；

Wherein R is₁、R₂、R₃、R₄、R₅Each independently is a hydrogen atom, a phenyl group, a naphthyl group, a biphenyl group, a terphenyl group or a pyridyl group, wherein each of the phenyl group, the naphthyl group, the biphenyl group, the terphenyl group or the pyridyl group is unsubstituted or substituted with one or more substituents selected from the group consisting of: protium atom, deuterium atom, tritium atom, methyl group, ethyl group, tert-butyl group or methoxy group; or

R₁、R₂、R₃、R₄、R₅Any two of which are bonded together to form a phenyl group, a naphthyl group, a phenanthryl group, a pyrenyl group, a dibenzofuranyl group, or a dibenzothiophenyl group;

R₆each occurrence, which is the same or different, is a single bond, phenyl, naphthyl, biphenyl, terphenyl, or pyridyl, wherein each of the phenyl, naphthyl, biphenyl, terphenyl, or pyridyl is unsubstituted or substituted with one or more substituents selected from the group consisting of: protium atom, deuterium atom, tritium atom, methyl group, ethyl group, tert-butyl group or methoxy group.

In a more preferred embodiment, the capping layer of the OLED device comprises an asymmetric triarylamine compound selected from the group consisting of:

except for compounds 006, 008, 016, 024, 045, 057, 062, 073, 076, 081, 090, 111, 114, 127, 129, 143, 159, 174, and 191 shown in the following synthetic examples, the above-mentioned remaining compounds are commercially available or prepared according to the method described in the patent kr 102060645.

The compounds of the general formula (1) according to the invention have excellent properties, with a higher refractive index of visible light and a suitable difference in refractive index in blue and red light, compared to the conventional symmetrical arylamine compounds for the same purpose. The asymmetric triarylamine compounds of the present invention have a refractive index in the range of 2.0 to 2.3, preferably 2.15 to 2.30, at a wavelength of blue light having a wavelength of 450 nm; the refractive index range of the green light with the wavelength of 525nm is 2.09-2.15; a refractive index in the range of 1.95 to 2.09, preferably 1.97 to 2.09, under red light having a wavelength of 620 nm; and the difference between the refractive indices for blue and red light is 0.2-0.3, preferably 0.2-0.25; most preferably 0.2-0.22. This is advantageous for improving the light extraction effect of the device and improving the viewing angle effect.

The compound of the general formula (1) of the invention also has a lower evaporation temperature of 270-.

The compounds of formula (1) according to the invention also have a shallow LUMO level, shallower than-2.8 eV, preferably (-2.6) - (-2.8) eV, which allows greater stability during encapsulation without blackening.

In another embodiment of the present invention, the capping layer in an organic electroluminescent (OLED) device comprises or consists of one or more of the compounds of formula (1) above; wherein the capping layer is 10-1000nm, preferably 40-140nm, more preferably 50-90nm, most preferably 65-75 nm.

Hereinafter, the structure and the manufacturing method of the OLED device of the present invention will be explained in further detail with reference to the accompanying drawings.

The OLED device comprises a substrate, a first electrode, an organic light-emitting functional layer, a second electrode and a covering layer, wherein the organic light-emitting functional layer can comprise a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer and the like, and can also only comprise the light-emitting layer and one or more other layers; wherein the cover layer comprises or consists of one or more of the compounds of the above general formula (1). Optionally, there is also a protective layer and an encapsulation layer over the cover layer.

As shown in fig. 1, the substrate layer 100 may be any substrate used in a typical organic light-emitting device. It may be a glass or transparent plastic substrate, a substrate of an opaque material such as silicon or stainless steel, or a flexible PI film. Different substrates have different mechanical strength, thermal stability, transparency, surface smoothness, water resistance, and different directions of use depending on the properties of the substrates.

The first electrode layer 200 is formed on the substrate layer 100, and the first electrode layer 200 may be a cathode or an anode. Here, the first electrode layer 200 may be a reflective electrode such as a reflective film formed of silver (Ag), magnesium (Mg), aluminum (Al), gold (Au), nickel (Ni), chromium (Cr), ytterbium (LiF), or an alloy thereof; and a transparent or semitransparent electrode layer having a high work function and formed on the reflective film.

The transparent or semitransparent electrode layer may be formed of Indium Tin Oxide (ITO), Indium Zinc Oxide (IZO), zinc oxide (ZnO), Aluminum Zinc Oxide (AZO), Indium Gallium Oxide (IGO), indium oxide (In)₂O₃) Or tin oxide (SnO)₂) Forming; or a combination of metals and oxides, such as ITO/Ag/ITO, IGO/Al/IGO, or AZO/Ag/AZO.

The first electrode layer 200 can be formed by a method such as sputtering, ion plating, vacuum evaporation, spin coating, electron beam evaporation, or Chemical Vapor Deposition (CVD), and is preferably formed by sputtering.

The thickness of the first electrode layer 200 depends on the material used, and is generally 5nm to 1 μm, preferably 10nm to 1 μm, more preferably 10nm to 500nm, particularly preferably 10nm to 300nm, and most preferably 10nm to 200 nm.

As shown in fig. 2, the organic light emitting function layer 300 may include an emission layer 340(EML), and a hole transport region may be formed between the EML and the first electrode layer 200, and an electron transport region may be formed between the EML and the second electrode layer 400. The hole transport region may include at least one of a hole injection layer 310(HIL), a hole transport layer 320(HTL), and an electron blocking layer 330 (EBL). The electron transport region may include at least one of a hole blocking layer 350(HBL), an electron transport layer 360(ETL), and an electron injection layer 370 (EIL). Accordingly, the organic light emitting function layer 300 includes at least 2 combinations of a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer, and an electron injection layer.

The thickness of the organic light emitting functional layer 300 is 50nm to 1000 nm.

As the materials of the hole injection layer, the hole transport layer, and the electron blocking layer (HIL310, HTL320, EBL330), any suitable material may be selected from known materials for OLED devices.

Examples of the above-mentioned materials may be phthalocyanine derivatives, triazole derivatives, triarylmethane derivatives, triarylamine derivatives, oxazole derivatives, oxadiazole derivatives, hydrazone derivatives, stilbene derivatives, pyridoline derivatives, polysilane derivatives, imidazole derivatives, phenylenediamine derivatives, amino-substituted quinone derivatives, styrylanthracene derivatives, styrylamine derivatives and other styrene compounds, fluorene derivatives, spirofluorene derivatives, silazane derivatives, aniline copolymers, porphyrin compounds, carbazole derivatives, polyarylalkane derivatives, polyphenylenes and their derivatives, polythiophenes and their derivatives, poly-N-vinylcarbazole derivatives, thiophene oligomers and other conductive polymer oligomers, aromatic tertiary amine compounds, styrene amine compounds, triamines, tetraamines, benzidine, propynediamine derivatives, hydrazone derivatives, stilbene derivatives, phenanthroline derivatives, and other derivatives, fluorine derivatives, and other derivatives, fluorine derivatives, and other compounds, fluorine derivatives, and fluorine, P-phenylenediamine derivatives, m-phenylenediamine derivatives, 1 '-bis (4-diarylaminophenyl) cyclohexane, 4, 4' -bis (diarylamine) biphenyls, bis [4- (diarylamino) phenyl ] methanes, 4, 4 '-bis (diarylamino) biphenyls, 4, 4' -bis (diarylamino) biphenyls, 4, 4 '-bis (diarylamino) diphenyl ethers, 4, 4' -bis (diarylamino) diphenyl sulfanes, bis [4- (diarylamino) phenyl ] dimethylmethanes, bis [4- (diarylamino) phenyl ] -bis (trifluoromethyl) methanes, or 2, 2-diphenylethylene compounds, and the like.

At least one of the HIL310 and the HTL320 may further include a charge generation material for improving conductivity. The charge generating material may be a p-dopant. Non-limiting compounds of P-dopants are for example: quinone derivatives such as Tetracyanoquinodimethane (TCNQ) and 2, 3, 5, 6-tetrafluoro-tetraethoxy-1, 4-benzoquinodimethane (F4-TCNQ); or hexaazatriphenylene derivatives, such as 2, 3, 6, 7, 10, 11-hexacyano-1, 4, 5, 8, 9, 12-hexaazatriphenylene (HAT-CN); or a cyclopropane derivative, such as 4, 4 ', 4 "- ((1E, 1' E, 1" E) -cyclopropane-1, 2, 3-trimethylenetri (oxycarbonylidene)) tris (2, 3, 5, 6-tetrafluorobenzyl); or metal oxides such as tungsten oxide and molybdenum oxide, but not limited thereto.

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 thickness of the hole transport layer of the present invention may be 5 to 200nm, preferably 10 to 150 nm.

The triplet state (T1) energy level of the required material in EBL330 is higher than the T1 energy level of the host material in the light-emitting layer 340, and can act as a barrier to energy loss of the light-emitting layer material; the HOMO energy level of the EBL330 material is between the HOMO energy level of the HTL320 material and the HOMO energy level of the main body material of the light-emitting layer 340, so that holes can be injected into the light-emitting layer from the positive electrode, and meanwhile, the EBL330 material is required to have high hole mobility, so that hole transmission is facilitated, and the application power of the device is reduced; the LUMO level of the EBL330 material is higher than that of the host material of the light emitting layer 340, and functions as an electron blocking, that is, the EBL330 material is required to have a wide forbidden bandwidth (Eg). The EBL330 material satisfying the above conditions may be triarylamine derivatives, fluorene derivatives, spirofluorene derivatives, dibenzofuran derivatives, carbazole derivatives, and the like. Among them, triarylamine derivatives such as N4, N4-bis ([1, 1 '-biphenyl ] -4-yl) -N4' -phenyl N4 '- [1, 1': 4 ', 1 "-terphenyl ] -4-yl- [1, 1 ' -biphenyl ] -4, 4 ' -diamine; spirofluorene derivatives, such as N- ([1, 1 '-diphenyl ] -4-yl) -N- (9, 9-dimethyl-9H-furan-2-yl) -9, 9' -spirobifluoren-2-amine; dibenzofuran derivatives such as N, N-bis ([1, 1 ' -biphenyl ] -4-yl) -3 ' - (dibenzo [ b, d ] furan-4-yl) - [1, 1 ' -biphenyl ] -4-amine, but not limited thereto.

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

In order to obtain a high-efficiency OLED device, the light emitting layer 340 may use the same doping material, or use multiple doping materials, the doping material may be a pure fluorescent material, a delayed fluorescence (TADF) material, or a phosphorescent material, or may be a combination of different fluorescent materials, TADF materials, and phosphorescence, and the light emitting layer 340 may be a single light emitting layer material, or may be a composite light emitting layer material stacked together in a transverse or longitudinal direction. The light-emitting layer 340 constituting the above-described OLED light-emitting body is exemplified by the following various configurations:

(1) a single organic light emitting layer material;

(2) the combination of the blue organic luminescent layer material and any one of the green, yellow or red luminescent layer materials is not divided into the front and the back;

(3) any two combinations of the blue organic luminescent layer material and the green, yellow or red luminescent layer material are not arranged in the front-back order;

(4) the blue organic light emitting layer material, the green organic light emitting layer material and the red organic light emitting layer material are transversely arranged as shown in fig. 3;

in order to adjust the effective combination of carrier charges in the light-emitting layer, the film thickness of the light-emitting layer 340 constituting the OLED light-emitting body may be arbitrarily adjusted as necessary, or light-emitting layers that are not colored may be alternately stacked and combined as necessary, or charge blocking layers for different functional purposes may be added to organic layers adjacent to the light-emitting layer.

The host material constituting the light-emitting layer of the above-mentioned OLED light-emitting device needs to have not only bipolar charge transport characteristics but also an appropriate energy level to efficiently transfer excitation energy generated by recombination of electrons and holes to a guest light-emitting material, i.e., a dopant material. Examples of such a material include a distyrylarylene derivative, a stilbene derivative, a carbazole derivative, a triarylamine derivative, an anthracene derivative, a pyrene derivative, a triazine derivative, a xanthone derivative, a triphenylene derivative, an azabenzene derivative, a coronene derivative, bis (2-methyl-8-quinoline) (p-phenylphenol) aluminum (BAlq), and the like.

As a guest material capable of generating blue fluorescence, blue phosphorescence, green fluorescence, green phosphorescence, and blue-green fluorescence, there is no particular limitation, and such a material is required to have not only extremely high fluorescence quantum emission efficiency but also an appropriate energy level to efficiently absorb excitation energy of a host material to emit light. Examples thereof include stilbene amine derivatives, pyrene derivatives, anthracene derivatives, triazine derivatives, xanthone derivatives, benzoxazole derivatives, benzothiazole derivatives, benzimidazole derivatives, chrysene derivatives, phenanthroline derivatives, distyrylbenzene derivatives, and tetraphenylbutadiene derivatives. Among them, 4' -bis [2- (9-ethylcarbazol-2-yl) -vinyl ] biphenyl (BCzVBi), perylene, and the like can be used, and there can be mentioned one or a combination of two or more kinds of compounds alone, such as tetrakisbenzene-based compounds, bisphenyl-based compounds, benzimidazole-based compounds, benzoxazole-based compounds, benzooxadiazole-based compounds, styrylbenzene compounds, distyrylpyrazine-based compounds, butadiene-based compounds, naphthalimide compounds, perillene-based compounds, aldazine-based compounds, cyclopentadiene-based compounds, pyrrolopyrrole-formyl-based compounds, styrylamine-based compounds, coumarine-based compounds, aromatic xylyleine-based compounds, metal complex compounds having 8-quinolphenol-based substances as ligands, or polyphenyl-based compounds. Among these compound materials, the present invention can be exemplified by specific examples of aromatic xylylline-based compounds such as: 4, 4 '-bis (2, 2-di-1-butylphenyl vinyl) diphenyl (abbreviated as DTBPBBi) or 4, 4' -bis (2, 2-diphenylvinyl) diphenyl (abbreviated as DPVBi), and the like and derivatives thereof.

The content (incorporation amount) of the fluorescent guest material with respect to the fluorescent host material is preferably 0.01 wt% to 20 wt%, more preferably 0.1 wt% to 10 wt%. When a blue fluorescent guest material is used as the fluorescent guest material, the content thereof is preferably 0.1 to 20 wt% with respect to the fluorescent host material. Within this range, an effective energy distribution between the high-energy blue emitter and the low-energy red emitter can be balanced, and desired electroluminescence with a balanced intensity of blue and red emissions can be obtained.

The light-emitting layer 340 included in the OLED device may be made of not only the fluorescent light-emitting material but also a phosphorescent material. Compared with fluorescent materials, the phosphorescent materials can simultaneously utilize singlet excitons and triplet excitons in the light emitting process, and theoretically, the internal quantum efficiency can reach 100 percent, so that the light emitting efficiency of the light emitting device can be greatly improved.

The blue phosphorescent dopant material is not particularly limited as long as it has a blue phosphorescent light-emitting function. Examples thereof include metal complexes of iridium, titanium, platinum, rhenium, palladium, and the like. Among these, complexes in which at least one of the ligands of the metal complex has a phenylpyridine skeleton, a bipyridine skeleton, a porphyrin skeleton, or the like are preferable. More specifically, bis [4, 6-difluorophenylpyridinium-N, C2 '] -picolinium iridium, tris [2- (2, 4-difluorophenyl) pyridium-N, C2' ] iridium, bis [2- (3, 5-trifluoromethyl) pyridium-N, C2 '] -picolinium iridium or bis [4, 6-difluorophenylpyridinium-N, C2' ] iridium acetylacetonate may be mentioned.

The green phosphorescent dopant is not particularly limited as long as it has a green phosphorescent light-emitting function. Examples of the phosphorescent dopant include metal complexes of iridium, ruthenium, platinum, rhenium, palladium, etc., and complexes having a phenylpyridine skeleton, a bipyridine skeleton, a porphyrin skeleton, etc., at least one of the ligands of the metal complexes, more specifically, iridium (ir (ppy)3) of the following formula (face) -tris (2-phenylpyridine), iridium bis [ 2-phenylpyridine-N, C2' ] -acetylacetonate, iridium (5-fluoro-2- (5-trifluoromethyl-2-pyridine) phenyl-C, N), etc.

Examples of the red phosphorescent dopant material include platinum (II) octaethylporphyrin (PtOEP), tris (2-phenylisoquinoline) iridium (ir (piq)3), bis (2- (2 '-benzothienyl) -pyridine-N, C3') iridium (acetylacetonate) (Btp2Ir (acac)), and the like.

The content (doping amount) of the phosphorescent dopant material is preferably 0.01 to 30% by weight, and more preferably 0.1 to 20% by weight, based on the phosphorescent host material. When a green phosphorescent dopant material is used, it is preferably 0.1 to 20 wt% with respect to the phosphorescent host material.

The phosphorescent host material is not particularly limited as long as the triplet energy is larger than that of the phosphorescent dopant. Examples thereof include carbazole derivatives, phenanthroline derivatives, triazine derivatives, triazole derivatives, and quinolinol-like metal complexes. Specific examples thereof include 4, 4 ', 4 ″ -tris (9-carbazolyl) triphenylamine, 4' -bis (9-carbazolyl) -2, 2 '-dimethylbiphenyl, 2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline (BCP), 3-phenyl-4- (1' -naphthyl) -5-phenylcarbazole, tris (8-quinolinolato) aluminum (Alq3), and bis- (2-methyl-8-quinolinolato-4- (phenylphenol) aluminum.

Besides the fluorescent or phosphorescent host-guest materials used in the light-emitting layer, the light-emitting layer materials can also adopt non-host-guest doped system materials, such as exciplex energy transfer, interface light emission and the like; the light-emitting layer material can also adopt a host-guest material with a Thermal Activation Delayed Fluorescence (TADF) function, and a mode that the TADF function material and the fluorescence and phosphorescence materials are mutually combined and matched.

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.

The materials constituting the hole blocking layer 350 and the electron transport layer 360 of the OLED device may be any materials selected from materials for OLEDs having electron transport properties. Examples of such a material include oxadiazole derivatives such as 1, 3-bis [5 ' - (p-tert-butylphenyl) -1, 3, 4-oxadiazol-2 ' -yl ] benzene, 2- (4-biphenyl) -5- (4-tert-butylphenyl) -1, 3, 4-oxadiazole, triazole derivatives such as 3- (4 ' -tert-butylphenyl) -4-phenyl-5- (4 "-biphenyl) -1, 2, 4-triazole, triazine derivatives, quinoline derivatives, quinoxaline derivatives, diphenoquinone derivatives, nitro-substituted fluorenone derivatives, thiopyran dioxide derivatives, anthraquinone dimethane derivatives, thiopyran dioxide derivatives, heterocyclic tetraanhydrides such as naphthyl perylene, carbodiimides, fluorene derivatives, and mixtures thereof, Anthraquinone dimethane derivatives, anthrone derivatives, distyrylpyrazine derivatives, silacyclopentadiene derivatives, phenanthroline derivatives, imidazopyridine derivatives, and the like.

Further, there may be mentioned organometallic complexes such as bis (10-benzo [ h ] quinolinolato) beryllium, beryllium salts of 5-hydroxybrass, aluminum salts of 5-hydroxybrass, and the like, or metal complexes of 8-hydroxyquinoline or derivatives thereof, such as tris (8-quinolinolato) aluminum (Alq), tris (5, 7-dichloro-8-quinolinolato) aluminum, bis (2-methyl-8-quinolinolato) (p-phenylphenolate) aluminum (BAlq), and tris (5, 7-dibromo-8-quinolinolato) aluminum. And metal chelator compounds containing a chelator, such as a quinolinol metal complex, such as a plant hormone (generally, 8-quinolinol) such as tris (2-methyl-8-quinolinol) aluminum. Examples of metal complexes in which the central metal of these metal complexes is replaced with beryllium, indium, magnesium, copper, calcium, tin, zinc, or aluminum are also given. It is preferable to use a nonmetal, a metal phthalocyanine or a substance having an alkyl group, a sulfo group or the like substituted at the terminal thereof. Among them, 2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline (BCP), 3-phenyl-4- (1' -naphthalene) -5-phenyl-1, 2, 4-Triazole (TAZ) are more preferably used.

The triplet state (T1) energy level of the required material in HBL350 is higher than the T1 energy level of the host material in the light-emitting layer 340, and can act as a barrier to energy loss of the light-emitting layer material; the HUMO energy level of the HBL350 material is lower than that of the main body material of the light-emitting layer 340, so that the effect of blocking holes is achieved, and meanwhile, the HBL350 material is required to have high electron mobility, so that electron transmission is facilitated, and the application power of the device is reduced; the HBL350 material satisfying the above conditions may be a triazine derivative, an azabenzene derivative, or the like. Among them, triazine derivatives are preferable; but is not limited thereto.

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 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 EIL370 may be formed from one or more of the following: an alkali metal; an alkaline earth metal; halides of alkali metals and alkaline earth metals; oxides of alkali metals and alkaline earth metals, carbonates of alkali metals and alkaline earth metals; alkali metal and alkaline earth metal oxalates or alkali metal and alkaline earth metal fluoroaluminates. Examples thereof include Li, Ca, Sr, LiF, CsF, BaO and Li₂CO₃、CaCO₃、Li₂C₂O₄、Cs₂C₂O₄、CsAlF₄. In some embodiments, the EIL370 can include at least one metal, such as one or more of Yb, Sc, V, Y, In, Ce, Sm, Eu, or Tb.

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 layer 400 is formed on the organic light emitting function layer 300, and may be a cathode, an anode, a transparent electrode, or a semi-transparent electrode. The second electrode layer 400 may be made of lithium, calcium, lithium fluoride/aluminum, silver, magnesium, or an alloy thereof into a thin film having a low work function. Further, the second electrode layer 400 may be made of an alloy including silver and at least one metal including aluminum, platinum, ytterbium, chromium, or magnesium. Also, the weight ratio of Ag in the alloy may be the same as the other metal ratio or greater or less than the weight of the other metal. For example: the second electrode layer 400 may be formed of an Ag — Mg alloy, wherein the mass ratio of Ag and Mg may be 90: 10 to 10: 90. Alternatively, the second electrode layer 400 may be formed of an alloy including at least one metal such as silver, gold, platinum, copper, nickel, or tungsten and at least one metal such as ytterbium, indium, magnesium, or chromium. These metal films can form transparent or translucent electrodes by adjusting the thickness of the film. Accordingly, light generated from the organic light emitting functional layer 300 may be emitted through the second electrode layer 400. Also, the second electrode layer 400 may have a thickness of 5 to 20 nm.

A capping layer 500 comprising or consisting of one or more of the compounds of the above general formula (1) is formed on the second electrode layer 400.

The thickness of the capping layer is 10-1000nm, preferably 40-140nm, more preferably 50-90nm, most preferably 60-75 nm.

Referring to fig. 1, the organic electroluminescent device of the present invention includes a substrate layer 100, a first electrode layer 200, an organic light emitting functional layer 300, a second electrode layer 400, and a cover layer 500.

A barrier layer (which may be composed of an inorganic material or/and an organic material for preventing foreign substances from penetrating the substrate and the device) and a wiring layer (which may include a driving TFT, a capacitor, a wire, and a low temperature polysilicon LTPS) may be formed on the substrate layer using a known method.

In a specific embodiment, the first electrode layer 200 may be a reflective electrode and the second electrode layer 400 is a transparent or semi-transparent electrode. Therefore, light generated from the organic light emitting functional layer 300 may be directly emitted from the second electrode layer 400, or may be reflected by the first electrode layer 200 to be emitted toward the second electrode layer 400. The first electrode layer 200 can be prepared by, for example, an evaporation method or a sputtering method. The second electrode layer 400 may be prepared by, for example, a vacuum evaporation method.

The organic light emitting function layer 300 may include an emission layer 340(EML), and a hole transport region may be formed between the EML and the first electrode layer 200, and an electron transport region may be formed between the EML and the second electrode layer 400. The hole transport region may include at least one of a hole injection layer 310(HIL), a hole transport layer 320(HTL), and an electron blocking layer 330 (EBL). The electron transport region may include at least one of a hole blocking layer 350(HBL), an electron transport layer 360(ETL), and an electron injection layer 370 (EIL).

The organic light emitting functional layer 300 may be composed of a small molecular organic material or a high molecular material, and the organic light emitting functional layer 300 may be prepared by various methods such as a vacuum evaporation method, solution spin coating, screen printing, and an inkjet printing method, for example.

The capping layer 500 may include or consist of one or more of the compounds of the above general formula (1), and the capping layer 500 may be prepared using various methods such as a vacuum evaporation method, solution spin coating, screen printing, an inkjet printing method, for example.

In addition, a full color organic electroluminescent device including the structure of fig. 3 may be prepared by referring to the structures of the organic electroluminescent devices of fig. 1 and 2. That is, the organic light emitting device according to the embodiments may be configured in various structures, such as a single color light emitting device, a multicolor light or a white light organic electroluminescent device.

A protective layer is provided on the cover layer 500. The protective layer comprises lithium fluoride (LiF). The thickness of the protective layer depends on the material used and is generally from 20 to 400nm, preferably from 30 to 200nm and more preferably from 40 to 100 nm.

An encapsulation layer is disposed on the protective layer. The encapsulation layer is a protective structure for preventing foreign substances such as moisture and oxygen from entering the organic layers of the organic electroluminescent device, and is a multi-layered thin film covering the entire surfaces of the organic light emitting functional layer, the capping layer, and the protective layer. Including a first encapsulating layer on the protective layer, a second encapsulating layer on the first encapsulating layer, and a second encapsulating layer on the second encapsulating layerA third encapsulation layer on the encapsulation layer; the first packaging layer is an inorganic layer; the second packaging layer is an organic layer; the third encapsulation layer is an inorganic layer; the inorganic layer comprises Al₂O₃、SiO_xN_y、TiO₂、SiO_xAnd SiN_xAt least one of the group consisting of x and y, which are the same or different, x and y independently of each other are greater than 0 and less than 10, preferably greater than 0 and less than 5, most preferably greater than 0 and less than 3. The inorganic layer is prepared by Chemical Vapor Deposition (CVD).

As the encapsulating layer organic material of the organic electroluminescent device of the present invention, an encapsulating layer organic material for an organic electroluminescent device known in the art can be used. In a preferred embodiment of the present invention, the used organic material of the encapsulation layer is Polydimethylsiloxane (PDMS), Polymethylmethacrylate (PMMA), Polystyrene (PS), a polymer derivative having a phenol group (phenoi group), an acrylic-based polymer (acryl-based polymer), an imide-based polymer (imide-based polymer), an aryl ether-based polymer (arylether-based polymer), an amide-based polymer (amide-based polymer), a fluorine-based polymer (fluorine-based polymer), a p-xylene-based polymer (p-xylene-based polymer), a vinyl alcohol-based polymer (vinyl alcohol-based polymer), or a mixture thereof.

The encapsulation layer organic material is thick enough to cover the encapsulation meta-layer and is cured to a polymer by UV curing.

According to the invention, the organic electroluminescent device is preferably a top-emitting organic electroluminescent device, which comprises that after an anode, a cathode and an organic light-emitting functional layer are prepared, a material containing the compound of the general formula (1) is evaporated on a light emergent side to be used as a covering layer, so that the light extraction efficiency is improved, the visual deviation effect is improved, and the black spot phenomenon is avoided.

The problem of viewing bias as referred to herein refers to a gradual change in the color of the emitted light when the device is viewed at different angles. In this context, the improvement of the viewing angle and the reduction of the angle dependence are realized in that the tendency of the emission color change is significantly reduced with the change of the observation angle, and the emission color does not change under an ideal state. The parameter JNCD (just NOTICEABLE COLOR difference) can be used for measuring, wherein JNCD is an obvious COLOR difference which can be perceived by human eyes, and the effect of improving the visual deviation is more obvious when the value of JNCD is smaller.

Furthermore, the OLED device of the present invention may be used in OLED lighting and display devices. In particular, it can be used in the commercial field, for example, display screens of products and equipment such as POS machines and ATM machines, copying machines, vending machines, game machines, kiosks, gas stations, card punches, access control systems, electronic scales, and the like; the field of communication, for example, display screens of products such as 3G mobile phones, various video intercom systems (videophones), mobile network terminals, ebooks (electronic books), and the like; the computer field, such as display screens of home and business computers (PC/workstation, etc.), PDAs and notebook computers; consumer electronics products, such as decorative items (soft screens) and lamps, various audio devices, MP3, calculators, digital cameras, head-mounted displays, digital video cameras, portable DVDs, portable televisions, electronic clocks, handheld game consoles, various household appliances (OLED televisions), and the like; in the traffic field, various kinds of indication display screens such as GPS, car audio, car phone, airplane instrument, and equipment are used.

Preferably, the OLED device prepared by the invention is used in the fields of smart phones, tablet computers and the like, the field of intelligent wearable devices, the field of large-size application such as televisions and the like, the field of VR and micro display, and automobile central control screens or automobile tail lamps.

Examples

The present invention will be described in detail with reference to the accompanying drawings and examples.

I. Synthetic examples

All raw materials and solvents were purchased from Zhongjieyan Wangrun GmbH, national drug group chemical reagents GmbH, Tokyo chemical industry Co., Ltd, and the solvents were used directly without further treatment.

Synthesis example 1 Synthesis of Compound 006

Step 1:

adding 0.012mol of raw material A-1, 0.010mol of raw material B-1 and 200ml of toluene into a 500ml three-neck flask under the protection of nitrogen, stirring and mixing, and then adding 5 multiplied by 10^-5mol Pd₂(dba)₃(tris (dibenzylideneacetone) dipalladium), 5X 10^-5mol P(t-Bu)₃Heating 0.03mol of sodium tert-butoxide to 105 ℃, carrying out reflux reaction for 24 hours, and taking a sample point plate to show that no bromide (namely the raw material B-1) is left, so that the reaction is complete; naturally cooling to room temperature, filtering, carrying out rotary evaporation on the filtrate until no fraction is obtained, and passing through a neutral silica gel column (the mobile phase is dichloromethane: petroleum ether in a volume ratio of 1: 1) to obtain a target product intermediate M-1; HPLC purity 99.8561%, yield 90.5%; elemental analysis Structure (molecular formula C)₃₆H₂₆N₂): theoretical value C, 88.86; h, 5.39; n, 5.76; test values are: c, 88.85; h, 5.40; and N, 5.75. MS (M/z) (M)⁺): the theoretical value is 486.21, and the actual value is 486.22.

Step 2:

adding 0.01mol of raw material C-1, 0.012mol of intermediate M-1 and 200ml of toluene into a 500ml three-neck flask under the protection of nitrogen, stirring and mixing, and then adding 5X 10^-5mol Pd₂(dba)₃、5×10^-5mol P(t-Bu)₃Heating 0.03mol of sodium tert-butoxide to 105 ℃, carrying out reflux reaction for 24 hours, and taking a sample point plate to show that no bromide (namely the raw material C-1) is left, so that the reaction is complete; naturally cooling to room temperature, filtering, rotary evaporating the filtrate until no fraction is obtained, and passing through a neutral silica gel column (the mobile phase is dichloromethane: petroleum ether in a volume ratio of 2: 1) to obtain the target product with the HPLC purity of 99.5244% and the yield of 88.1%. Elemental analysis Structure (molecular formula C)₄₉H₃₃N₃O) theoretical value: c, 86.57; h, 4.89; n, 6.18; test values are: c, 86.58; h, 4.87; and N, 6.19. MS (M/z) (M +): theoretical value: 679.26, found: 679.28.

in analogy to compound 006Synthetic procedures other compounds of the invention are prepared, except for the starting materials of the reaction. The starting material A, B, C used and the corresponding product are shown in table 1. In addition, structural characterization was also performed, the molecular weight was measured using MS, and NMR at 400MHz (JEOL 400MHz) was used as deuterated chloroform (CDCl)₃) Is a solvent assay¹The results of H-NMR are shown in Table 2.

TABLE 1

TABLE 2

Determination of physical Properties of Compounds

The determination method comprises the following steps: the refractive index n and the extinction coefficient k (glass substrate isotropy) were measured by an ellipsometer (U.S. J.A. Woollam Co. model: ALPHA-SE) (test is atmospheric environment); the highest occupied molecular orbital HOMO energy level is tested by photoelectron spectroscopy (IPS-3) (tested in an atmospheric environment); the forbidden band width Eg is tested by a double-beam ultraviolet visible spectrophotometer (Beijing Pusan general company, model: TU-1901); the lowest unoccupied molecular orbital LUMO energy level is calculated by the following formula: LUMO ═ HOMO + Eg; preparation of a bilayer film on alkali-free glass: alkali-free glass/CP (70nm)/LiF (80nm), performing PT treatment (high-energy plasma) in a metal cavity of a vacuum evaporation device for 30min, and observing whether the film is blackened (black spot phenomenon occurs); heat resistance experiments were carried out using a thermal stability apparatus (model BOF-800C-8D).

The compound of the present invention and the comparative compound CP1 were measured by the above-mentioned measurement methods. The test data are shown in tables 3 and 4 below.

Comparative compound CP1, entitled N, N-phenyl-N, N- (9-phenyl-3-carbazolyl) -1, 1 '-biphenyl-4, 4' -diamine, CAS number 887402-92-8, was purchased commercially.

TABLE 3

TABLE 4

Note: the evaporation temperature is 500mm at TS (vertical distance from evaporation substrate to evaporation source), the vacuum degree is less than 1.0E-5Pa, and the evaporation rate is

The vapor deposition temperature. The judgment criteria for material decomposition are: and (4) subtracting HPLC after heat resistance from HPLC before heat resistance by more than 0.1 percent, namely, the difference of HPLC before heat resistance and HPLC after heat resistance is more than 0.1 percent, and judging the decomposition. And (4) detecting whether the black spots appear or not through a microscope to observe whether the black spots appear or not.

As can be seen from the data in Table 3, compared with the comparative compound CP1, the compound of the present invention has higher refractive indexes under blue light, green light and red light, which is beneficial to improving the light extraction efficiency of OLED devices. Meanwhile, the compound of the present invention has a suitable difference value in the range of 0.308 to 0.115 between the refractive index difference under blue light and the refractive index difference under red light, which is advantageous for reducing color shift, thereby improving the viewing shift effect of the screen. In addition, the compounds of the invention have shallow LUMO energy level, generally lower than-2.80 ev, preferably in the range of (-2.6) - (-2.8) ev, which is beneficial to the stability of materials in the CVD packaging process, and can not generate black spot phenomenon, thereby ensuring that the yield of OLED devices is higher, therefore, the organic electroluminescent device of the invention has good application effect and industrialization prospect.

As can be seen from the data in table 4 above, the compound of the present invention has a lower evaporation temperature than the comparative compound CP1, and the decomposition temperature of the material is higher than the evaporation temperature of the material, thereby ensuring thermal stability at the evaporation temperature. In addition, the compound of the general formula (1) has a low extinction coefficient and a high refractive index in the field of visible light, and can effectively improve the light extraction efficiency of an OLED device and reduce power consumption after being applied to the OLED device as a covering layer.

In conclusion, the compound has a shallow LUMO energy level and good thermal stability; and excellent refractive indices in blue, green and red, especially with a suitable range of differences between the refractive indices in blue and red.

Device embodiments

The beneficial technical effect of the compounds of the present invention as capping layers for application in OLED devices is further illustrated by the following device examples, wherein R, G, B, W represents red, green, blue and white light, respectively.

1. Materials, apparatus and test methods used in the examples

Material sources are as follows: commercially purchased or synthesized by itself.

The molecular structural formula of the related material is shown as follows:

equipment:

a vacuum deposition apparatus: 200mm vapor deposition equipment of Japan Changzhou industry

The test method comprises the following steps:

determination of current efficiency, CIEx, CIEy, perceptible color difference (JNCD):

the following OLED devices in device examples and device comparative examples were tested using an IVL (Current-Voltage-Brightness) test system (Fushida scientific instruments, Suzhou) and software EILV20060707, and data on IVL characteristic curves, efficiency-Current Density curves, color coordinate positions, etc. were obtained. At @10mA/cm²The data under the conditions are standard (namely the test current density reaches 10 mA/cm)²The corresponding performance values).

2. Example of adjusting device film thickness

A device comprising the compound of the present invention and a comparative material CP1 as a cap layer was prepared, the thickness of the cap layer was varied, and the properties of the device were measured.

(1) Device film thickness adjustment example 1-1: use of the Compound 006 of the present invention as a coating Material

The device structure is as follows: substrate layer 100/first electrode (anode) layer 200(ITO (15nm)/Ag (150nm)/ITO (15 nm))/hole injection layer 310(HT 1: HI 1: 97: 3 mass ratio, thickness 10 nm)/hole transport layer 320(HT 1, thickness 120 nm)/electron blocking layer 330(EB 1, thickness 10 nm)/light-emitting layer 340(BH 1: BD 1: 97: 3 mass ratio, thickness 20 nm)/hole blocking/electron transport layer 360(ET 1: LiQ: 1 mass ratio, thickness 30 nm)/electron injection layer 370(LiF, thickness 1 nm)/second electrode (cathode) layer 400 (Mg: Ag 1: 9 mass ratio, thickness 16 nm)/capping layer 500 (inventive compound 006, thickness 60 nm).

The preparation method comprises the following steps: the substrate layer is a PI film, and ITO (15nm)/Ag (150nm)/ITO (15nm) anode layers are washed, namely alkali washing, pure water washing and drying are sequentially carried out, and then ultraviolet-ozone washing is carried out to remove organic residues on the surface of the anode layer. On the anode layer after the above washing, HT 1 and HI 1 having a film thickness of 10nm were deposited as hole injection layers by a vacuum deposition apparatus, and the mass ratio of HT 1 to HI 1 was 97: 3. Then, HT 1 was evaporated to a thickness of 120nm as a hole transport layer. EB 1 was then evaporated to a thickness of 10nm as an electron blocking layer. And after the evaporation of the electron blocking material is finished, manufacturing a light emitting layer of the OLED light emitting device, wherein BH 1 is used as a main material, BD 1 is used as a doping material, the mass ratio of BH 1 to BD 1 is 97: 3, and the thickness of the light emitting layer is 20 nm. And continuing vacuum evaporation of ET 1 and LiQ after the light-emitting layer, wherein the mass ratio of ET 1 to LiQ is 1: 1, the film thickness is 30nm, and the layer is a hole blocking/electron transporting layer. On the hole-blocking/electron-transporting layer, a LiF layer having a film thickness of 1nm, which is an electron-injecting layer, was fabricated by a vacuum evaporation apparatus. An Mg/Ag electrode layer having a thickness of 16nm was formed on the electron injection layer by a vacuum deposition apparatus, and the mass ratio of Mg to Ag was 1: 9, and this layer was used as a cathode layer. On the cathode layer, the compound 006 of the present invention was vacuum-deposited as a capping layer to a film thickness of 60 nm.

(2) Device film thickness adjustment examples 1-2 to 1-5

The device structure and the manufacturing method are similar to those of device film thickness adjustment example 1-1, except that: the film thicknesses of the covering layers were 65nm, 70nm, 75nm, and 80nm, respectively, as described in Table 5 below.

(3) Device film thickness adjustment examples 2-1 to 2-5

The device structure and the manufacturing method are similar to those of device film thickness adjustment example 1-1, except that: the use of the inventive compound 045 as a cover material; and the film thicknesses of the capping layers were 60nm, 65nm, 70nm, 75nm, and 80nm, respectively, as described in table 5 below.

(4) Comparative device film thickness adjustment examples 1-1 to 1-5

The device structure and the manufacturing method are similar to those of device film thickness adjustment example 1-1, except that: comparative compound CP1 was used as the capping layer material; and the film thicknesses of the capping layers were 60nm, 65nm, 70nm, 75nm, and 80nm, respectively, as described in table 5 below.

TABLE 5

Note: index is current efficiency/CIEy, and is only applied to blue light devices, and the efficiency of the blue light devices is generally not referred to current efficiency, but is referred to Index (an industry standard);

as can be seen from the data in Table 5 above, the current efficiency (index as reference data) of OLED devices comprising compounds 006 and 045 of the present invention fluctuates in the range of 151.9-156.1 and 153.8-155.5, respectively, at capping layers of 60-80nm as compared to comparative compound CP 1; and comparative compound CP1, which had a fluctuation range of 135.7-143.0. Clearly, the OLED devices containing the compounds of the present invention show less fluctuation in efficiency, indicating that device efficiency is less affected by film thickness. Thus, wider film thicknesses can be allowed for the fabrication of the devices of the present invention while also maintaining stability in device efficiency.

3. Blue light device embodiments

Blue devices comprising the compounds of the invention and the comparative material CP1 as a cover layer were prepared and the properties of the devices were determined.

(1) Blue device example B-1: use of the Compound 006 of the present invention as a coating Material

The device structure is as follows: substrate layer 100/first electrode (anode) layer 200(ITO (15nm)/Ag (150nm)/ITO (15 nm))/hole injection layer 310(HT 1: HI 1: 97: 3 mass ratio, thickness 10 nm)/hole transport layer 320(HT 1, thickness 120 nm)/electron blocking layer 330(EB 1, thickness 10 nm)/light-emitting layer 340(BH 1: BD 1: 97: 3 mass ratio, thickness 20 nm)/hole blocking/electron transport layer 360(ET 1: LiQ: 1 mass ratio, thickness 30 nm)/electron injection layer 370(LiF, thickness 1 nm)/second electrode (cathode) layer 400 (Mg: Ag 1: 9 mass ratio, thickness 16 nm)/capping layer 500 (inventive compound 006, thickness 70 nm).

The preparation method comprises the following steps: the substrate layer is a PI film, and ITO (15nm)/Ag (150nm)/ITO (15nm) anode layers are washed, namely alkali washing, pure water washing and drying are sequentially carried out, and then ultraviolet-ozone washing is carried out to remove organic residues on the surface of the anode layer. On the anode layer after the above washing, HT 1 and HI 1 having a film thickness of 10nm were deposited as hole injection layers by a vacuum deposition apparatus, and the mass ratio of HT 1 to HI 1 was 97: 3. Then, HT 1 was evaporated to a thickness of 120nm as a hole transport layer. EB 1 was then evaporated to a thickness of 10nm as an electron blocking layer. And after the evaporation of the electron blocking material is finished, manufacturing a light emitting layer of the OLED light emitting device, wherein BH 1 is used as a main material, BD 1 is used as a doping material, the mass ratio of BH 1 to BD 1 is 97: 3, and the thickness of the light emitting layer is 20 nm. And continuing vacuum evaporation of ET 1 and LiQ after the light-emitting layer, wherein the mass ratio of ET 1 to LiQ is 1: 1, the film thickness is 30nm, and the layer is a hole blocking/electron transporting layer. On the hole-blocking/electron-transporting layer, a LiF layer having a film thickness of 1nm, which is an electron-injecting layer, was fabricated by a vacuum evaporation apparatus. An Mg/Ag electrode layer having a thickness of 16nm was formed on the electron injection layer by a vacuum deposition apparatus, and the mass ratio of Mg to Ag was 1: 9, and this layer was used as a cathode layer. On the cathode layer, 70nm of the compound 006 of the present invention was vacuum-evaporated as a capping layer.

(2) Blue light device examples B-2 to B-19

The device structure and fabrication method are similar to blue device embodiment B-1, except that other compounds of the invention are used as the capping layer material; specific compounds are described in table 6 below.

(3) Blue light device comparative example B-0

The device structure and fabrication method are similar to blue device example B-1, except that a comparative compound was used as the capping layer material; specific compounds are described in table 6 below.

The test data for the material of the cap layer in the blue OLED device, the current efficiency of the device, CIEx, CIEy, and perceived color difference are listed in table 6.

TABLE 6

perceptible color difference, unit: JNCD; 1 JNCCD ═ 0.004

4. Green light device embodiments

A green device comprising the compound of the invention and the comparative material CP1 as a cap layer was prepared and the properties of the device were determined.

(1) Green device example G-1: use of the Compound 006 of the present invention as a coating Material

The device structure is as follows: transparent substrate layer 100/first electrode (anode) layer 200(ITO (15nm)/Ag (150nm)/ITO (15 nm))/hole injection layer 310(HT 1: HI 1: 97: 3 mass ratio, thickness 10 nm)/hole transport layer 320(HT 1, thickness 120 nm)/electron blocking layer 330(EB 7, thickness 30 nm)/light emitting layer 340(GH 1: GH-2: GD 1: 47: 6 mass ratio, thickness 30 nm)/hole blocking/electron transport layer 360(ET 1: LiQ: 1 mass ratio, thickness 30 nm)/electron injection layer 370(LiF, thickness 1 nm)/second electrode (cathode) layer 400 (Mg: Ag: 1: 9 mass ratio, thickness 16 nm)/capping layer 500 (inventive compound 006, thickness 70 nm).

The preparation method comprises the following steps: the substrate layer is a PI film, and ITO (15nm)/Ag (150nm)/ITO (15nm) anode layers are washed, namely alkali washing, pure water washing and drying are sequentially carried out, and then ultraviolet-ozone washing is carried out to remove organic residues on the surface of the anode layer. On the anode layer after the above washing, HT 1 and HI 1 having a film thickness of 10nm were deposited as hole injection layers by a vacuum deposition apparatus, and the mass ratio of HT 1 to HI 1 was 97: 3. Then, HT 1 was evaporated to a thickness of 120nm as a hole transport layer. EB 7 was then evaporated to a thickness of 30nm as an electron blocking layer. After the evaporation of the electron blocking material is finished, a light-emitting layer of the OLED light-emitting device is manufactured, wherein GH 1 and GH 2 are used as main materials, GD 1 is used as a doping material, the mass ratio of GH 1, GH 2 and GD 1 is 47: 6, and the thickness of the light-emitting layer is 30 nm. And continuing vacuum evaporation of ET 1 and LiQ after the light-emitting layer, wherein the mass ratio of ET 1 to LiQ is 1: 1, the film thickness is 30nm, and the layer is a hole blocking/electron transporting layer. On the hole-blocking/electron-transporting layer, a LiF layer having a film thickness of 1nm, which is an electron-injecting layer, was fabricated by a vacuum evaporation apparatus. An Mg/Ag electrode layer having a thickness of 16nm was formed on the electron injection layer by a vacuum deposition apparatus, and the mass ratio of Mg to Ag was 1: 9, and this layer was used as a cathode layer. On the cathode layer, 70nm of the compound 006 of the present invention was vacuum-evaporated as a capping layer.

(2) Green light device examples G-2 to G-19

The device structure and fabrication method are similar to green device embodiment G-1, except that other compounds of the invention are used as the capping layer material; specific compounds are described in table 7 below.

(3) Comparative green light device example G-0

The device structure and fabrication method are similar to green device example G-1, except that a comparative compound was used as the capping layer material; specific compounds are described in table 7 below.

The materials of the cover layers in the green OLED devices, the current efficiency of the devices, CIEx, CIEy, and the test data for the perceived color difference are listed in table 7.

TABLE 7

5. Red light device embodiments

A red light device comprising the compound of the present invention and a comparative material CP1 as a cap layer was prepared, and the properties of the device were measured.

(1) Red device example R-1: use of the Compound 006 of the present invention as a coating Material

The device structure is as follows: transparent substrate layer 100/first electrode (anode) layer 200(ITO (15nm)/Ag (150nm)/ITO (15 nm)/hole injection layer 310(HT 1: HI 1: 97: 3 mass ratio, thickness 10 nm)/hole transport layer 320(HT 1, thickness 120 nm)/electron blocking layer 330(EB 9, thickness 80 nm)/light emitting layer 340(RH 1: RD 1: 97: 3 mass ratio, thickness 30 nm)/hole blocking/electron transport layer 360(ET 1: Liq: 1 mass ratio, thickness 30 nm)/electron injection layer 370(LiF, thickness 1 nm)/second electrode (cathode) layer 400 (Mg: Ag 1: 9 mass ratio, thickness 16 nm)/capping layer 500 (inventive compound 006, thickness 70 nm).

The preparation method comprises the following steps: the substrate layer is a PI film, and ITO (15nm)/Ag (150nm)/ITO (15nm) anode layers are washed, namely alkali washing, pure water washing and drying are sequentially carried out, and then ultraviolet-ozone washing is carried out to remove organic residues on the surface of the anode layer. On the anode layer after the above washing, HT 1 and HI 1 having a film thickness of 10nm were deposited as hole injection layers by a vacuum deposition apparatus, and the mass ratio of HT 1 to HI 1 was 97: 3. Then, HT 1 was evaporated to a thickness of 120nm as a hole transport layer. EB 9 was then evaporated to a thickness of 80nm as an electron blocking layer. After the evaporation of the electron blocking material is finished, a light emitting layer of the OLED light emitting device is manufactured, RH 1 is used as a main material, RD 1 is used as a doping material, the mass ratio of BH 1 to BD 1 is 97: 3, and the thickness of the light emitting layer is 30 nm. And continuing vacuum evaporation of ET 1 and LiQ after the light-emitting layer, wherein the mass ratio of ET 1 to LiQ is 1: 1, the film thickness is 30nm, and the layer is a hole blocking/electron transporting layer. On the hole-blocking/electron-transporting layer, a LiF layer having a film thickness of 1nm, which is an electron-injecting layer, was fabricated by a vacuum evaporation apparatus. An Mg/Ag electrode layer having a thickness of 16nm was formed on the electron injection layer by a vacuum deposition apparatus, and the mass ratio of Mg to Ag was 1: 9, and this layer was used as a cathode layer. On the cathode layer, 70nm of the compound 006 of the present invention was vacuum-evaporated as a capping layer.

(2) Red light device embodiments R-2 through R-19

The device structure and fabrication method are similar to those of red device embodiment R-1, except that other compounds of the invention are used as the capping layer material; specific compounds are described in table 8 below.

(3) Comparative example R-0 of Red light device

The device structure and fabrication method are similar to red device embodiment R-1, except that a comparative compound was used as the capping layer material; specific compounds are described in table 8 below.

The test data for the material of the cover layer in the red OLED device, the current efficiency of the device, CIEx, CIEy, and the perceived color difference are listed in table 8.

TABLE 8

It is understood that the smaller the perceived color difference, the smaller the chromaticity variation amount, which indicates that the better the angle dependence of the wavelength of the outgoing light of the organic electroluminescent device is suppressed.

The data in tables 6, 7 and 8 show that the OLED devices prepared with the compounds of the present invention as the capping layer have less perceptible color difference in the blue, green and red fields, and thus have less angle change and significantly improved color shift compared to the comparative device examples.

In terms of device efficiency, the current efficiency of the OLED device prepared by using the compound of the invention as the covering layer in the fields of blue light, green light and red light is remarkably improved compared with the comparative device.

6. Color cast effect of white light device

For a given light, i.e. containing CIE (x, y) and luminance L. The luminance and color coordinates of a white light mixed from red, green, and blue monochromatic devices can be calculated by the following formula (see Yongming Yin, et al, "Evolution of white organic light-emitting devices: from organic research to lighting and display applications," mater. chem. front., 2019, 3, 970) as follows:

wherein r, g, b, w represent red, green, blue and white, respectively; x and y represent CIE coordinate values of corresponding colors; l represents the luminance value of the corresponding color.

The coordinates of red, green and blue colors and the brightness obtained by the test at different angles are substituted into the above formula, which is the color coordinates and the brightness of the white light at different angles, as shown in table 9. The white light color shift results for the white light devices are summarized in table 10.

Watch 10

Fig. 4 shows a luminance decay spectrum of the white light device, which shows the luminance decay of the white light with a change in angle.

Fig. 5 shows color shift data of the white light device, which indicates the change of color coordinates of white light with a change of angle and data converted into JNCD values.

As can be seen from table 10, for the white light device in which three monochromatic devices of red, green, and blue were mixed, the white light device including the compound of the present invention as a cap layer had a significantly improved white color shift effect compared to the comparative example using the compound CP1 device.

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 comprising:

a substrate layer;

a first electrode over the substrate;

an organic light emitting functional layer over the first electrode;

a second electrode over the organic light emitting functional layer; and

a cover layer over the second electrode;

wherein the capping layer comprises an asymmetric triarylamine compound represented by general formula (1):

x is O, S, Se or N-R₆；

L represents a single bond, phenylene or biphenylene;

Y is represented by O, S, Se or N-R₆；

R₁、R₂、R₃、R₄、R₅Any two adjacent of them can be combined together to form C₆-C₃₀Aryl or C₂-C₃₀Heteroaryl group, wherein C₆-C₃₀Aryl or C₂-C₃₀Each heteroaryl is unsubstituted or substituted with one or more substituents selected from: protium atom, deuterium atom, tritiumAtom, (C)₁-C₆) Alkyl or (C)₁-C₆) An alkoxy group;

2. The organic electroluminescent device according to claim 1, wherein in the general formula (1),

x is O, S or N-R₆；

L represents a single bond, phenylene or biphenylene;

Y is represented by O, S or N-R₆；

Wherein R is₁、R₂、R₃、R₄、R₅Each independently is a hydrogen atom, a phenyl group, a naphthyl group, a biphenyl group, a terphenyl group, or a pyridyl group, wherein each of the phenyl group, the naphthyl group, the biphenyl group, the terphenyl group, and the pyridyl group is unsubstituted or substituted with one or more substituents selected from the group consisting of a protium atom, a deuterium atom, a tritium atom, a methyl group, an ethyl group, a tert-butyl group, and a methoxy group; or

R₁、R₂、R₃、R₄、R₅Any two of which are bonded together to form a naphthyl group, a phenanthryl group, a pyrenyl group, a dibenzofuranyl group, or a dibenzothiophenyl group;

R₆each occurrence, which is the same or different, is a single bond, phenyl, naphthyl, biphenyl, terphenyl or pyridyl, wherein phenyl, naphthyl, biphenyl, terphenyl or pyranylPyridyl groups are each unsubstituted or substituted with one or more substituents selected from: protium atom, deuterium atom, tritium atom, methyl group, ethyl group, tert-butyl group or methoxy group.

3. The organic electroluminescent device according to claim 1, wherein the compound of the formula (1) is selected from the following specific compounds,

4. an organic electroluminescent device according to any one of claims 1 to 3, the asymmetric triarylamine compound having a refractive index in the range of 2.0 to 2.3, preferably 2.15 to 2.30, under blue light having a wavelength of 450 nm; the refractive index range of the green light with the wavelength of 525nm is 2.09-2.15; a refractive index in the range of 1.95 to 2.09, preferably 1.97 to 2.09, under red light having a wavelength of 620 nm; and the difference between the refractive indices for blue and red light is 0.2-0.3, preferably 0.20-0.25; most preferably 0.20-0.22.

5. The organic electroluminescent device according to any of claims 1 to 3, wherein the asymmetric triarylamine compound is evaporated at a temperature less than the decomposition temperature, wherein the evaporation temperature is from 270 ℃ to 380 ℃, preferably from 300 ℃ to 375 ℃, and more preferably from 355 ℃ to 369 ℃; the LUMO energy level is shallower than-2.8 eV, and (-2.6) - (-2.8) eV is preferable.

6. The organic electroluminescent device according to any of claims 1 to 3, the thickness of the cover layer being from 10 to 1000nm, preferably from 40 to 140nm, more preferably from 50 to 90nm, most preferably from 65 to 75 nm.

7. An organic electroluminescent device according to any one of claims 1 to 6, wherein the capping layer comprises or consists of one or more of the asymmetric triarylamine compounds described in any one of claims 1 to 6.

8. An organic electroluminescent device according to any one of claims 1 to 7, wherein the device comprises one or more combinations of layers of blue, green or red organic light emitting material; the different organic light-emitting material layers are combined in a transverse or longitudinal superposition mode.

9. A display comprising one or more organic electroluminescent devices as claimed in any one of claims 1 to 8; and in the case where a plurality of devices are included, the devices are combined in a lateral or longitudinal superposition.

10. A display according to claim 9 wherein the capping layer of the device comprises or consists of one or more of the asymmetric triarylamine compounds defined in any one of claims 1 to 6.