CN114605402B

CN114605402B - Organic compound containing triazine structure and application thereof

Info

Publication number: CN114605402B
Application number: CN202011432846.4A
Authority: CN
Inventors: 吴逸; 叶中华; 唐丹丹; 张兆超; 李崇
Original assignee: Jiangsu Sunera Technology Co Ltd
Current assignee: Jiangsu Sunera Technology Co Ltd
Priority date: 2020-12-09
Filing date: 2020-12-09
Publication date: 2023-09-26
Anticipated expiration: 2040-12-09
Also published as: CN114605402A

Abstract

The application discloses a compound taking benzimidazole or benzoxazole substituted triazine as a core and application thereof, and belongs to the technical field of semiconductor materials. The compound takes the structure of benzimidazole or benzoxazole substituted triazine as a core, and is connected with aromatic groups to improve the performance, and the formed compound has the characteristics of higher glass transition temperature, higher molecular heat stability, good electron mobility, lower evaporation temperature, proper HOMO/LUMO energy level and the like. When the compound is used as a material of an organic electroluminescent device, the driving voltage, the current efficiency and the service life of the device are all obviously improved.

Description

Organic compound containing triazine structure and application thereof

Technical Field

The application relates to the technical field of semiconductor materials, in particular to an organic compound containing a triazine structure and application thereof in an organic electroluminescent device.

Background

The organic electroluminescent device (OLED: organic Light Emission Diodes) technology can be used for manufacturing novel display products and novel illumination products, is hopeful to replace the existing liquid crystal display and fluorescent lamp illumination, and has wide application prospect. The OLED device has a sandwich-like structure and comprises electrode material film layers and organic functional materials clamped between different electrode film layers, and various functional materials are mutually overlapped together according to purposes to jointly form the OLED light-emitting device. When voltage is applied to the electrodes at the two ends of the OLED light-emitting device serving as a current device and positive and negative charges in the organic layer functional material film layer are acted through an electric field, the positive and negative charges are further compounded in the light-emitting layer, and thus OLED electroluminescence is generated.

Currently, the OLED display technology has been applied in the fields of smart phones, tablet computers and the like, and further will expand to the large-size application fields of televisions and the like. However, the performance of the OLED device, such as the luminous efficiency and the service life, needs to be further improved compared to the actual product application requirements. Current research into improving performance of OLED light emitting devices includes: reducing the driving voltage of the device, improving the luminous efficiency of the device, prolonging the service life of the device, and the like. In order to realize the continuous improvement of the performance of the OLED device, innovation is needed from the angles of the structure and the manufacturing process of the OLED device, and research and innovation are needed for the OLED photoelectric functional material, so that an OLED functional material with higher performance is created.

The OLED photoelectric functional materials applied to OLED devices can be divided into two main categories in terms of application, namely charge injection transport materials and luminescent materials. Further, the charge injection transport material may be further classified into an electron injection transport material, an electron blocking material, a hole injection transport material, and a hole blocking material, and the light emitting material may be further classified into a host light emitting material and a doping material. In order to manufacture high-performance OLED light emitting devices, various organic functional materials are required to have good photoelectric properties, for example, as a charge transport material, good carrier mobility, high glass transition temperature, and the like, and as a host material of a light emitting layer, good bipolar properties, appropriate HOMO/LUMO energy levels, and the like are required. For an OLED device, electrons are injected from the cathode and then transferred to the host material through the electron transport layer, where they recombine with holes, thereby generating excitons. Therefore, the injection capability and the transmission capability of the electron transmission layer are improved, the device driving voltage is reduced, and meanwhile, the high-efficiency electron-hole recombination efficiency is obtained. Therefore, the electron transport layer is very important, and it is required to have high electron injection capability, transport capability, and high durability of electrons.

The heat resistance and film stability of the material are also important for device lifetime. A material having low heat resistance is likely to be decomposed not only at the time of material vapor deposition but also by heat generated by the device at the time of device operation, and causes material deterioration. Under the condition of poor phase stability of the material film, the material also generates film crystallization in a short time, so that the organic film layer is directly separated, and the device is deteriorated. Therefore, the materials used are required to have high heat resistance and good film stability.

With the remarkable progress of OLED devices, the performance requirements for materials are increasing, not only are they required to have good material stability, but also to achieve good efficiency and lifetime at low driving voltages. However, the current electron transport materials have insufficient heat resistance stability, and at the same time, the electron tolerance of the materials has defects, so that the materials are separated or decomposed in a phase state when the device works.

Disclosure of Invention

In view of the foregoing problems of the prior art, the applicant of the present application provides an organic compound containing a triazine structure and applications thereof.

One object of the present application is an organic compound containing a triazine structure, the structure of which is represented by the general formula (1):

in the general formula (1), X is O or N-R ₃ Preferably represented by O;

R ₁ 、R ₂ and R is ₃ Independently represent phenyl, biphenyl, naphthyl, pyridyl, phenanthryl, carbazolyl or dibenzofuranyl, preferably phenyl, naphthyl or dibenzofuranyl;

Ar ₁ independent is represented by phenyl, cyano-substituted phenyl, fluoro-substituted phenyl, biphenyl, cyano-substituted biphenyl, fluoro-substituted biphenyl, terphenyl, naphthyl, pyridyl, phenanthryl, triphenylenyl, benzotriphenylenyl, dibenzofuranyl, benzodibenzofuranyl, carbazolyl, N-phenylcarbazolyl, 9-dimethylfluorenyl, spirofluorenyl, pyrenyl or phenyl-substituted dibenzofuranyl, preferably phenyl, terphenyl, pyridyl, phenanthryl, triphenylenyl, carbazolyl, dibenzofuranyl.

The compound is one of the general formulas (2) - (7);

the compound is one of the general formulas (8) - (17);

the specific structure of the organic compound is any one of the following structures:

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another object of the present application is to provide the use of the organic compound containing a triazine structure according to the present application as an electron transport layer material in an organic electroluminescent device.

It is still another object of the present application to provide an organic electroluminescent device comprising the organic compound containing a triazine structure according to the present application.

It is a further object of the present application to provide a display element comprising the organic electroluminescent device according to the present application.

Advantageous effects

The compound takes benzimidazole or benzoxazole substituted triazine group connection as a core, has higher glass transition temperature, electron tolerance and molecular heat stability, proper HOMO/LUMO energy level, lower evaporation temperature and good electron mobility. Therefore, when the organic light emitting diode is used as an electron transport material of an OLED functional layer, the photoelectric performance of an OLED device can be effectively improved, and the service life of the device can be effectively prolonged.

The compounds formed by using benzimidazole or benzoxazole substituted triazine groups as the parent nucleus exhibit excellent properties. The LUMO electron cloud distribution of the compound is further delocalized, so that the electron resistance of the material can be improved, and the electron stability of the material can be effectively improved. In addition, the parent nucleus can increase weak interaction in molecules, effectively reduce the vapor deposition temperature of the molecules and improve the thermal durability of the material. Furthermore, the parent nucleus can inhibit pi-pi accumulation among molecules, so that the electron mobility of the molecules is obviously improved, and the driving voltage of the device is reduced. In addition, due to the existence of the electricity absorption conjugation function of the mother nucleus, the glass transition temperature of the material is improved, and the film stability of the material is effectively improved. Therefore, the compound can be used as an electron transport material to effectively reduce the driving voltage of the device, improve the efficiency of the device and prolong the service life of the device.

The compounds employed in the present application are prepared by linking a benzimidazole or benzoxazole substituted triazine to an aromatic group at a specific site. As can be understood from examples (described later), the compound having the above structure has a high glass transition point Tg (for example, 130 ℃ or higher), a low vapor deposition temperature (for example, less than 280 ℃) and a high electron mobility (more than 3.0×e-4 cm) ² Vs), stable film stability, excellent heat resistance, and higher electron mobility.

In addition, compared with the LUMO energy level (more than or equal to 3.0 eV) of a common electron transport material, the compound has a shallower LUMO energy level (less than or equal to 2.9 eV). The shallower LUMO energy level can effectively reduce the electron injection energy barrier between the LUMO energy level and the light emitting layer or the hole blocking layer, and improve the electron injection capability. Therefore, the compound is used as an electron transport material, has excellent electron transport capacity and good electron injection property, and can effectively reduce the driving voltage of a device, improve the efficiency of the device and prolong the service life of the device.

Drawings

Fig. 1 is a schematic diagram of the structure of the materials listed in the present application applied to an OLED device. In the figure, 1 is a transparent substrate layer, and 2 is a first electrode layer, i.e., an anode layer; 3 is a hole injection layer, 4 is a hole transport layer, 5 is an electron blocking layer, 6 is a light emitting layer, 7 is an electron transport layer, 8 is an electron injection layer, 9 is a second electrode layer, i.e. a cathode layer, and 10 is an optical coupling layer.

Detailed Description

The technical aspects of the present application will be described in detail below with reference to embodiments.

In one embodiment of the present application, there is provided an organic compound having a triazine structure, the structure of the compound being represented by general formula (1):

in the general formula (1), X is O or N-R ₃ ；

R ₁ 、R ₂ And R is ₃ Independently represent phenyl, biphenyl, naphthyl, pyridyl, phenanthryl, carbazolyl or dibenzofuranyl;

Ar ₁ independent is represented by phenyl, cyano-substituted phenyl, fluoro-substituted phenyl, biphenyl, cyano-substituted biphenyl, fluoro-substituted biphenyl, terphenyl, naphthyl, pyridyl, phenanthryl, triphenylenyl, dibenzofuranyl, benzodibenzofuranyl, carbazolyl, N-phenylcarbazolyl, 9-dimethylfluorenyl, spirofluorenyl, pyrenyl, or phenyl-substituted dibenzofuranyl.

In the present application, HOMO means the highest occupied orbital of a molecule, and LUMO means the lowest unoccupied orbital of a molecule unless otherwise specified. Furthermore, in the present application, HOMO and LUMO energy levels are expressed in absolute values, and the comparison between energy levels is also a comparison of the magnitudes of the absolute values thereof, and those skilled in the art know that the larger the absolute value of an energy level, the lower the energy of the energy level.

Any numerical range recited herein is intended to include all sub-ranges subsumed therein with the same numerical accuracy. For example, "1.0 to 10.0" means all subranges included between the minimum value of 1.0 listed and the maximum value of 10.0 listed (and including 1.0 and 10.0), that is, all subranges having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0. Any maximum numerical limitation listed herein is meant to include all smaller numerical limitations, and any minimum numerical limitation listed herein is meant to include all larger numerical limitations, all smaller numerical limitations, and all smaller numerical limitations, all larger numerical limitations, and all smaller numerical limitations, all as recited herein are meant to be included herein. Accordingly, the applicant reserves the right to modify the present specification including the claims to expressly describe any subranges falling within the scope of the explicit description herein.

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

In the present application, in describing the electrodes and the organic electroluminescent device, and other structures, words such as "upper" and "lower" used to indicate orientations are merely indicative of orientations in a certain specific state, and do not mean that the relevant structure can only exist in the orientations; conversely, if the structure can be repositioned, for example inverted, the orientation of the structure is changed accordingly. Specifically, in the present application, the "lower" side of an electrode refers to the side of the electrode that is closer to the substrate during fabrication, while the opposite side that is farther from the substrate is the "upper" side.

Process for preparing compounds

The compound according to the present application is generally obtained by subjecting arylboronic acid and aryl halide to SUZUKI coupling reaction in the presence of a catalyst such as palladium acetate, for example, in a basic environment such as with addition of potassium carbonate, in a solvent such as DMF, to obtain a product, and purifying the product to obtain the compound of the present application having a purity of 99% or more.

Organic electroluminescent device

In another embodiment of the present application, there is provided an organic electroluminescent device comprising a first electrode, a second electrode, and a plurality of organic thin film layers between the first electrode and the second electrode, wherein at least one of the organic thin film layers contains the organic compound having a benzimidazole or benzoxazole substituted triazine as a core.

In a preferred embodiment of the present application, the organic thin film layer comprises an electron transport layer, wherein the electron transport layer comprises the benzimidazole-or benzoxazole-substituted triazine-based organic compound according to the present application. Preferably, the electron transport layer comprises, in addition to the organic compound according to the application, further electron transport materials, such as Liq (see examples for specific chemical structures).

In a preferred embodiment of the present application, the organic electroluminescent device according to the present application comprises a substrate, a first electrode layer, an organic thin film layer, a second electrode layer, and an optical coupling layer, wherein the organic thin film layer includes, but is not limited to, a light emitting layer, and a hole injection layer, a hole transport layer, an electron blocking layer, an electron transport layer, an electron blocking layer, and/or an electron injection layer.

The preferred device structure of the present application takes the form of top emission (top emission). Preferably, the anode of the organic electroluminescent device of the present application employs an electrode having high reflectivity, preferably ITO/Ag/ITO; the cathode adopts a transparent electrode, preferably adopts a mixed electrode of Mg/Ag=1:9, thereby forming a microcavity resonance effect, and the light emitted by the device is emitted from the side of the Mg/Ag electrode.

In a preferred embodiment of the present application, there is provided an organic electroluminescent device comprising a substrate, an anode, a cathode, a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, an electron transport layer, an electron injection layer, and a cathode layer, wherein the anode is over the substrate, the hole injection layer is over the anode, the hole transport layer is over the hole injection layer, the electron blocking layer is over the hole transport layer, the light emitting layer is over the hole transport layer, the electron transport layer is over the light emitting layer, the electron injection layer is over the electron transport layer, the cathode layer is over the electron injection layer, and the optical coupling layer is over the cathode.

Hereinafter, the structure of the organic electroluminescent device according to an embodiment of the present application will be described in detail with reference to fig. 1.

As shown in fig. 1, according to one embodiment of the present application, the present application provides an organic electroluminescent device comprising 1, a substrate, in order from bottom to top; 2. a first electrode layer; 3. a hole injection layer; 4. a hole transport layer; 5. an electron blocking layer; 6. a light emitting layer; 7. an electron transport layer; 8. an electron injection layer; 9. a second electrode layer; 10. an optical coupling layer.

As the substrate of the organic electroluminescent device of the present application, any substrate commonly used for organic electroluminescent devices may be used. Examples are transparent substrates, such as glass or transparent plastic substrates; an opaque substrate such as a silicon substrate; a flexible PI film substrate. Different substrates have different mechanical strength, thermal stability, transparency, surface smoothness, and water repellency. The use direction of the substrate is different according to the property of the substrate. In the present application, a transparent substrate is preferably used. The thickness of the substrate is not particularly limited.

A first electrode is formed on the substrate, and the first electrode and the second electrode may be opposite to each other. The first electrode may be an anode or a cathode. The anode material is preferably a material having a high work function so that holes are easily injected into the organic functional material layer. Non-limiting examples of anode materials include, but are not limited to, indium Tin Oxide (ITO), indium Zinc Oxide (IZO), tin oxide (SnO ₂ ) Zinc oxide (ZnO), magnesium (Mg), aluminum (Al), silver (Ag), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), and magnesium-silver (Mg-Ag). The first electrode may have a single-layer structure or a multi-layer structure including two or more layers. For example, the anode may have a three-layer structure of ITO/Ag/ITO, but is not limited thereto. In addition, the thickness of the anode depends on the materials used, typically 50-500nm, preferably 70-300nm and more preferably 100-200nm.

The hole injection layer 3, the hole transport layer 4, and the electron blocking layer 5 may be disposed between the first electrode 2 and the light emitting layer 6.

The hole injection layer structure is such that a hole injection layer material, which may be, for example, a P dopant, is uniformly or non-uniformly dispersed in the hole transport layer. The P-dopant may be selected from at least one compound selected from the group consisting of: quinone derivatives such as Tetracyanoquinodimethane (TCNQ) or 2,3,5, 6-tetrafluoro-tetracyano-1, 4-benzoquinone dimethane (F4-TCNQ); metal oxides such as tungsten oxide or molybdenum oxide; or cyano-containing compounds, such as compounds P1, NDP and F4-TCNQ shown below:

according to the application, P1 is preferably used as P dopant. The ratio of the hole transport layer to the P dopant used in the present application is 99:1 to 70:30, preferably 99:1 to 85:15 and more preferably 97:3 to 87:13 on a mass basis.

The thickness of the hole injection layer of the present application may be 1 to 100nm, preferably 2 to 50nm and more preferably 5 to 20nm.

The material of the hole transport layer is preferably a material having high hole mobility, which enables holes to be transferred from the anode or the hole injection layer to the light emitting layer. The hole transporting material may be a styrene compound such as a phthalocyanine derivative, a triazole derivative, a triarylmethane derivative, a triarylamine derivative, an oxazole derivative, an oxadiazole derivative, a hydrazone derivative, a stilbene derivative, a pyridinine derivative, a polysilane derivative, an imidazole derivative, a phenylenediamine derivative, an amino-substituted quininone derivative, a styrylanthracene derivative, a styrylamine derivative, a fluorene derivative, a spirofluorene derivative, a silazane derivative, an aniline copolymer, a porphyrin compound, a carbazole derivative, a polyarylalkane derivative, a polyphenylene ethylene and a derivative thereof, a polythiophene and a derivative thereof, a poly-N-vinylcarbazole derivative, a conductive polymer oligomer such as a thiophene oligomer, an aromatic tertiary amine compound, a styrylamine compound, a triamine, a tetramine, a biphenylamine, a propienediamine derivative, a p-phenylenediamine derivative, a m-phenylenediamine derivative, 1 '-bis (4-diarylaminophenyl) cyclohexane, 4' -bis [4- (diarylamino) phenyl ] methane, 4 '-bis (diarylamino) triphenylamine-type) biphenyl, 4' -bis (diarylamino) biphenyl ether, 4 '-bis (diarylamino) 4' -diarylmethane, 4 '-bis (diarylamino) methane, 4' -diarylmethane, 4 '-bis (diarylmethane) or 4' -diarylmethane, 2-diphenylethylene compound, etc.

The thickness of the hole transport layer of the present application may be 5 to 200nm, preferably 10 to 180nm and more preferably 20 to 150nm.

The electron blocking layer requires that the triplet state (T1) energy level of the material is higher than the T1 energy level of the main body material in the light emitting layer, and can play a role in blocking the energy loss of the light emitting layer material; the HOMO energy level of the electron blocking layer material is between the HOMO energy level of the hole transport layer material and the HOMO energy level of the luminescent layer main body material, so that holes are injected into the luminescent layer from the positive electrode, and meanwhile, the electron blocking layer material is required to have high hole mobility, hole transport is facilitated, and the application power of the device is reduced; the LUMO energy level of the electron blocking layer material is higher than that of the host material of the light emitting layer, and plays a role in blocking electrons, that is, the electron blocking layer material is required to have a wide forbidden bandwidth (Eg). The electron blocking layer material satisfying the above conditions may be a triarylamine derivative, a fluorene derivative, a spirofluorene derivative, a dibenzofuran derivative, a carbazole derivative, or 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' -spirobifluorene-2-amine; dibenzofuran derivatives such as, but not limited to, N-di ([ 1,1' -biphenyl ] -4-yl) -3' - (dibenzo [ b, d ] furan-4-yl) - [1,1' -biphenyl ] -4-amine.

According to the application, the thickness of the electron blocking layer may be 1 to 200nm, preferably 5 to 150nm and more preferably 10 to 100nm.

According to the application, the light emitting layer is located between the first electrode and the second electrode. The material of the light emitting layer is a material capable of emitting visible light by receiving holes from the hole transporting region and electrons from the electron transporting region, respectively, and combining the received holes and electrons. The light emitting layer may include a host material and a dopant material. The host material and the guest material of the light-emitting layer of the organic electroluminescent device can be one or two of anthracene derivatives, quinoxaline derivatives, phenylpyridine derivatives, xanthone derivatives, diphenyl ketone derivatives, carbazole derivatives, pyridine derivatives and pyrimidine derivatives. The guest material can be pyrene derivative, boron derivative, flexo derivative, spirofluorene derivative, iridium complex or platinum complex.

The hole blocking layer may be disposed over the light emitting layer. The triplet state (T1) energy level of the hole blocking layer material is higher than the T1 energy level of the luminescent layer main body material, so that the effect of blocking the energy loss of the luminescent layer material can be achieved; the HOMO energy level of the material is lower than that of the main body material of the luminescent layer, so that the hole blocking effect is achieved, and meanwhile, the hole blocking layer material is required to have high electron mobility, so that electron transmission is facilitated, and the application power of the device is reduced; the hole blocking layer material satisfying the above conditions may be a phenylpyridine derivative, an azabenzene derivative, or the like. Among them, phenylpyridine derivatives are preferable; but is not limited thereto.

The thickness of the light-emitting layer of the present application may be 5 to 60nm, preferably 5 to 30nm, more preferably 5 to 20nm.

An electron transport layer may be disposed over the hole blocking layer. The electron transport layer material is a material that easily receives electrons of the cathode and transfers the received electrons to the light emitting layer. The electron transport layer comprises or consists of one or more organic compounds according to the application or of one or more compounds according to the application which are based on benzothiazole-or benzoxazole-substituted triazines. Preferably, the electron transport layer is composed of the organic compound of the present application and other electron transport layer materials. More preferably, the other electron transport layer material is an electron transport material commonly used in the art. Most preferably, the electron transport layer consists of the organic compound of the present application and Liq.

In the electron transport layer of the organic electroluminescent device according to the application, the ratio of the organic compound according to the application and the other electron transport layer material is 1:9 to 9:1, preferably 2:8 to 8:2, more preferably 4:6 to 6:4, most preferably 5:5.

As the electron transporting compound of the present application, one or more of compound 1, compound 4, compound 7, compound 9, compound 11, compound 20, compound 22, compound 24, compound 16, compound 27, compound 122, compound 31, compound 61, compound 67, compound 71, compound 75, compound 80, compound 81, compound 82, and compound 84 are preferably used.

The thickness of the electron transport layer of the present application may be 10 to 80nm, preferably 20 to 60nm, more preferably 25 to 45nm.

In a preferred embodiment of the present application, the electron injection layer material is preferably a material metal Yb having a low work function so that electrons are easily injected into the organic functional material layer. The thickness of the electron injection layer of the present application may be 0.1 to 5nm, preferably 0.5 to 3nm, more preferably 0.8 to 1.5nm.

In one embodiment of the application, the second electrode may be a cathode or an anode, as previously described. In the present application, the second electrode is preferably used as the cathode. The material used to form the cathode may be a material having a low work function, such as a metal, an alloy, a conductive compound, or a mixture thereof. Non-limiting examples of cathode materials may include lithium (Li), ytterbium (Yb), magnesium (Mg), aluminum (Al), calcium (Ca), and aluminum-lithium (Al-Li), magnesium-indium (Mg-In), and magnesium-silver (Mg-Ag). The thickness of the cathode is generally 5 to 100nm, preferably 7 to 50nm and more preferably 10 to 25nm, depending on the material used.

Optionally, in order to improve the light-emitting efficiency of the organic electroluminescent device, a light coupling layer (i.e. a CPL layer) may be further added on the second electrode (i.e. the cathode) of the device. According to the principle of optical absorption and refraction,the higher the refractive index of the CPL cladding material, the better, and the smaller the absorption coefficient, the better. Any material known in the art may be used as the CPL layer material, e.g., alq ₃ . The CPL coating typically has a thickness of 5-300nm, preferably 20-100nm and more preferably 40-80nm.

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

Method for preparing organic electroluminescent device

The present application also relates to a method of manufacturing the above organic electroluminescent device, comprising sequentially laminating a first electrode, a plurality of organic thin film layers, and a second electrode on a substrate. Wherein the multi-layered organic thin film layer is formed by sequentially laminating a hole transport region, a light emitting layer, and an electron transport region, i.e., sequentially laminating a hole injection layer, a hole transport layer, and an electron blocking layer, on the first electrode from bottom to top, and sequentially laminating a hole blocking layer, an electron transport layer, and an electron injection layer, i.e., sequentially laminating a hole transport layer, an electron transport layer, and an electron injection layer, on the light emitting layer, from bottom to top. In addition, optionally, an optical coupling layer (CPL layer) may be further laminated on the second electrode to improve the light extraction efficiency of the organic electroluminescent device.

As for lamination, methods such as vacuum deposition, vacuum evaporation, spin coating, casting, LB method, inkjet printing, laser printing, or LITI may be used, but are not limited thereto. Wherein vacuum evaporation means heating and plating a material onto a substrate in a vacuum environment.

In the present application, the layers are preferably formed using a vacuum evaporation method, wherein the layers may be formed at a temperature of about 100-500 ℃ at about 10 ^-8 -10 ^-2 Vacuum level of the tray and the likeVacuum evaporation was performed at a rate of (2). Preferably, the temperature is 200-400 ℃, more preferably 250-300 ℃. The vacuum degree is preferably 10 ^-6 -10 ^-2 Torr, more preferably 10 ^-5 -10 ^-3 Torr. The rate is about->More preferably about->

The material for forming each layer according to the present application may be used as a single layer by forming a film alone, or may be used as a single layer by forming a film after mixing with another material, or may be a laminated structure between layers formed by forming a film alone, a laminated structure between layers formed by mixing, or a laminated structure between layers formed by forming a film alone and layers formed by mixing.

Display device

The application also relates to a display device, in particular a flat panel display device, comprising the organic electroluminescent device. In a preferred embodiment, the display apparatus may comprise one or more of the above-described organic electroluminescent devices, and in the case of comprising a plurality of devices, the devices are combined in a stacked manner, either laterally or longitudinally. The display device may further include at least one thin film transistor. The thin film transistor may include a gate electrode, source and drain electrodes, a gate insulating layer, and an active layer, wherein one of the source and drain electrodes may be electrically connected to a first electrode of the organic electroluminescent device. The active layer may include crystalline silicon, amorphous silicon, an organic semiconductor, or an oxide semiconductor, but is not limited thereto.

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

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

Examples

I. Preparation of Compounds example

The present application will be described in detail below with reference to the drawings and examples.

All materials and reactants in the examples below were purchased from medium energy saving wanrun stock.

Synthesis of intermediate A-1:

in a three-necked flask, nitrogen was introduced, 0.022mol of raw material A-1, and 0.0002mol of raw material C-1, 100ml DMF,0.02mol, palladium acetate were added, followed by stirring, and then 0.03mol of K was added ₃ PO ₄ The aqueous solution was heated to reflux for 16 hours, the spot plate was sampled and the reaction was complete. Naturally cooling, pouring the reaction solution into a 500ml beaker, adding 250ml distilled water, mechanically stirring for 20min, carrying out suction filtration on the mixed solution, leaching a filter cake with 200ml distilled water for 2 times, and leaching with 100ml ethanol to obtain white solid powder. Finally, the white solid powder was purified by column chromatography on silica gel using an eluent of ethyl acetate: petroleum ether=1:4 to give intermediate a-1

Product LC-MS: accurate quality: 552.44, found 553.48 ([ M+H)] ⁺ )。

Synthesis of intermediate A-2:

the synthesis of intermediate A-2 is similar to that of intermediate A-1, except that starting material C-2 is substituted for starting material C-1.

Product LC-MS: accurate quality: 602.50, found 603.45 ([ M+H)] ⁺ )。

Synthesis of intermediate A-3:

the synthesis of intermediate A-2 is similar to that of intermediate A-1, except that starting material C-3 is substituted for starting material C-1.

Product LC-MS: accurate quality: 652.56, found 653.51 ([ M+H)] ⁺ )。

Synthesis of intermediate A-4:

the synthesis of intermediate A-2 is similar to that of intermediate A-1, except that starting material C-4 is substituted for starting material C-1.

Product LC-MS: accurate quality: 652.56, found 653.61 ([ M+H)] ⁺ )。

Synthesis of intermediate A-5:

the synthesis of intermediate A-2 is similar to that of intermediate A-1, except that starting material C-5 is substituted for starting material C-1.

Product LC-MS: accurate quality: 642.52, found 643.59 ([ M+H)] ⁺ )。

Synthesis of intermediate A-6:

the synthesis of intermediate A-6 is similar to that of intermediate A-1, except that starting material A-1 is replaced with starting material A-2.

Product LC-MS: accurate quality: 627.56, found 628.59 ([ M+H)] ⁺ )。

Example 1: synthesis of Compound 1:

in a three-necked flask, nitrogen was introduced, 0.022mol of intermediate A-1, 100ml DMF,0.02mol raw material B-1,0.0002mol of palladium acetate was added, followed by stirring, and then 0.03mol of K was added ₃ PO ₄ The aqueous solution was heated to reflux for 16 hours, the spot plate was sampled and the reaction was complete. Naturally cooling, pouring the reaction solution into a 500ml beaker, adding 250ml distilled water, mechanically stirring for 20min, carrying out suction filtration on the mixed solution, leaching a filter cake with 200ml distilled water for 2 times, and leaching with 100ml ethanol to obtain white solid powder. Finally, the white solid powder was purified by column chromatography on silica gel using an eluent of ethyl acetate: petroleum ether=1:4 to give compound 1.

The procedure of example 1 was repeated to synthesize the following compounds; wherein the reaction conditions were similar except that intermediate a and starting material B listed in table 1 below were used:

TABLE 1

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The nmr hydrogen spectrum data of the compounds prepared in the examples herein are shown in table 2:

TABLE 2

The organic compound of the present application is used in a light-emitting device, and can be used as an electron transport material. The HOMO/LUMO energy level, the glass transition temperature Tg, the decomposition temperature Td, the S1 energy level, the T1 energy level, the evaporation temperature and the electron mobility were measured for the inventive compound and the comparative compound, respectively, and the measurement results are shown in table 3. Wherein the comparative compounds ET-1, ET-2 and ET-3 have the following structures:

TABLE 3 Table 3

Note 1: triplet energy level T1 is tested by a fluorescent-3 series fluorescence spectrometer of Horiba, and the test condition of the material is 2 x 10 ^-5 Toluene solution of mol/L. The glass transition temperature Tg is determined by differential scanning calorimetry (DSC, german fast Co., DSC204F1 differential scanning calorimeter) at a heating rate of 10 ℃/min. The thermal weight loss temperature Td is a temperature at which the weight loss is 1% in a nitrogen atmosphere, and is measured on a TGA-50H thermogravimetric analyzer of Shimadzu corporation, the nitrogen flow rate is 20mL/min. The highest occupied molecular orbital HOMO energy level was tested by the ionization energy measurement system (IPS 3), tested as an atmospheric environment. The evaporation temperature is 10 degrees of vacuum ^-4 At Pa, the material evaporation rate isTemperature at that time. The electron mobility was measured using the time of flight (TOF) method, and the measuring equipment was CMM-250 for Japan spectroscopy. S1 and T1 were tested using a Horiba (Fluorolog-3) fluorescence spectrometer, where S1 was tested at room temperature and T1 was tested at 77K. Eg, lumo=homo-Eg was tested by a double beam uv-vis spectrophotometer (beijing general purpose company, model: TU-1901).

From the data of Table 3It can be seen that the HOMO level of the organic compound according to this example is between 6.2-6.49 eV; LUMO energy levels between 2.67-2.9 eV; s1 is between 3.28 and 3.76 eV; tg is between 130.9 and 140 ℃; td is 390.5-401.7 ℃, and evaporation temperature is 260.9-273.5 ℃; electron mobility is 4.31-4.68X10E ^-4 cm ² between/Vs.

The organic compound has more proper HOMO and LUMO energy levels and triplet energy level (T1 is more than or equal to 2.5 eV), can be used as an electron transport material of an organic electroluminescent device, has good carrier mobility, and can effectively reduce the driving voltage of the device. The glass transition temperature of the material is higher than 120 ℃, which shows that the material has good film stability and inhibits crystallization of the material. In addition, the material has higher vitrification transfer temperature and decomposition temperature, so that the evaporation thermal stability of the material is improved, and the working stability of devices prepared from the material is improved. Finally, the material has lower evaporation temperature, and the difference between the evaporation temperature and the decomposition temperature is further increased, so that the evaporation stability of the material can be effectively improved, and the industrial window of material evaporation is improved.

Device preparation examples

The effect of the compound synthesized according to the present application on the use as an electron transport material in a device will be described in detail below with reference to device examples 1 to 20 and device comparative examples 1 to 3. Device examples 2-20 and device comparative examples 1-3 were identical in the fabrication process and the same substrate material and electrode material were used, and the film thickness of the electrode material was also kept uniform, except that the material of the electron transport layer of the device was changed, as compared with device example 1. The device stack structure is shown in table 4, and the performance test results of each device are shown in table 5.

Device example 1

Substrate layer 1/anode layer 2 (ITO (15 nm)/Ag (150 nm)/ITO (15 nm))/hole injection layer 3 (HT-1:p-1=97:3 mass ratio, thickness 10 nm)/hole transport layer 4 (HT-1, thickness 130 nm)/electron blocking layer 5 (EB-1, thickness 10 nm)/light emitting layer 6 (BH-1:bd-1=97:3 mass ratio, thickness 20 nm)/electron transport layer 7 (compound 1:liq mass ratio 1:1, thickness 35 nm)/electron injection layer 8 (Yb, thickness 1 nm)/cathode layer 9 (Mg: ag=1:9 mass ratio, thickness 15 nm)/optical coupling layer 10 (CPL-1, thickness 70 nm).

The preparation process comprises the following steps:

as shown in fig. 1, the substrate layer 1 is a glass substrate, and the ITO (15 nm)/Ag (150 nm)/ITO (15 nm) anode layer 2 is washed, that is, alkali washing, pure water washing, drying are sequentially performed, and then ultraviolet-ozone washing is performed to remove organic residues on the surface of the anode layer. On the anode layer 2 after the above washing, HT-1 and P-1 having film thicknesses of 10nm were vapor deposited as hole injection layers 3 by a vacuum vapor deposition apparatus, and the mass ratio of HT-1 and P-1 was 97:3. Next, HT-1 was evaporated to 130nm thickness as a hole transport layer 4. Subsequently EB-1 was evaporated to a thickness of 10nm as an electron blocking layer 5. After the evaporation of the electron blocking material is finished, the light emitting layer 6 of the OLED light emitting device is manufactured, and the structure of the light emitting layer comprises BH-1 used by the OLED light emitting layer 6 as a main material, BD-1 as a doping material, the mass ratio of BH-1 to BD-1 is 97:3, and the film thickness of the light emitting layer is 20nm. Continuing vacuum evaporation of the compound 1 and Liq, wherein the mass ratio of the compound 1 to Liq is 1:1, the film thickness is 35nm, and the electron transport layer 7 is formed. On the electron transport layer 7, a Yb layer having a film thickness of 1nm was formed by a vacuum vapor deposition apparatus, and this layer was an electron injection layer 8. On the electron injection layer 8, an Mg/Ag electrode layer having a film thickness of 15nm was prepared by a vacuum vapor deposition apparatus, and the mass ratio of Mg to Ag was 1:9, and this layer was used as the cathode layer 9. On the cathode layer 9, CPL-1 of 70nm was vacuum deposited as an optical coupling layer 10.

Device example 2 to device example 20

An organic electroluminescent device was prepared in the same manner as in device example 1 except that the compounds shown in Table 2 were used in place of the electron-transporting compound 1, wherein the evaporation rates were controlled to be respectivelyAnd->The specific device structure is shown in table 3.

Device comparative example 1 to device comparative example 3

An organic electroluminescent device was fabricated in the same manner as in device example 1, except that the electron-transporting compound 1 in device example 1 was replaced with the compounds shown in Table 2, respectively, in which the evaporation rates were controlled to be respectivelyAnd->The specific device structure is shown in table 4.

After the electroluminescent device was fabricated according to the above procedure, the luminance decay lifetime of the device was measured for efficiency data, and the results are shown in table 5. The molecular structural formula of the related material is shown as follows:

the structures of the comparative compounds ET-1, ET-2 and ET-3 are described above. The above materials are all commercially available.

TABLE 4 Table 4

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Device test examples

The devices prepared in II were tested for driving voltage, current efficiency, CIEx, CIEy and LT95 lifetime. Voltage, current efficiency, CIEx, CIEy using IVL (current-voltage-brightness) measurementsTest system (Freund's scientific instruments Co., ltd.) with a current density of 10mA/cm ² . LT95 refers to the time taken for the device brightness to decay to 95% of the initial brightness, and the current density at the time of testing is 20mA/cm ² The method comprises the steps of carrying out a first treatment on the surface of the The life test system is an EAS-62C type OLED device life tester of Japanese systems research company.

The test results are shown in Table 5 below.

TABLE 5

As can be seen from the device test data results of table 5 above, the device driving voltage prepared using the inventive compounds as electron transport layer materials was significantly reduced while at the same time the current efficiency was significantly improved and the device lifetime was greatly prolonged, as compared to the comparative devices using ET-1, ET-2 and ET-3 as electron transport layer materials.

The foregoing description of the preferred embodiments of the application is not intended to limit the application to the precise form disclosed, and any such modifications, equivalents, and alternatives falling within the spirit and scope of the application are intended to be included within the scope of the application.

Claims

1. An organic compound containing triazine, which is characterized in that the structure of the compound is shown as a general formula (1):

in the general formula (1), X is represented by O;

R ₁ independently represent phenyl, biphenyl, naphthyl or dibenzofuranyl;

R ₂ independently represented by phenyl, biphenylA group or a naphthyl group;

Ar ₁ independent is represented by phenyl, cyano-substituted phenyl, fluoro-substituted phenyl, biphenyl, cyano-substituted biphenyl, fluoro-substituted biphenyl, terphenyl, naphthyl, pyridyl, phenanthryl, triphenylenyl, dibenzofuranyl, N-phenylcarbazolyl, 9-dimethylfluorenyl, pyrenyl or phenyl-substituted dibenzofuranyl.

2. The compound according to claim 1, wherein in the compound

X is represented by O;

R ₁ independently represent phenyl, naphthyl, dibenzofuranyl;

R ₂ independently represented by phenyl, naphthyl;

Ar ₁ independently represent phenyl, terphenyl, pyridyl, phenanthryl, triphenylene, dibenzofuranyl.

3. The compound according to claim 1, wherein the compound is one of the general formulae (2) to (6);

4. the compound according to claim 1, wherein the compound is one of the general formulae (8) to (17):

5. the compound according to any one of claims 1 to 4, wherein the specific structure of the organic compound is any one of the following structures:

6. an organic electroluminescent device comprising a first electrode, a second electrode, and an organic thin film layer between the first electrode and the second electrode, wherein the organic thin film layer comprises an electron transport layer comprising one or more compounds according to any one of claims 1 to 5.

7. The organic electroluminescent device according to claim 6, comprising, in order, a substrate (1), a first electrode layer (2), a hole injection layer (3), a hole transport layer (4), an electron blocking layer (5), a light emitting layer (6), an electron transport layer (7), an electron injection layer (8), a second electrode layer (9), and an optical coupling layer (10).

8. The organic electroluminescent device of claim 7, wherein the electron transport layer further comprises lithium octahydroxyquinoline.

9. A display element comprising the organic electroluminescent device as claimed in any one of claims 6 to 8.