Compound containing pyrimidine and oxa-spirofluorene structure, organic electroluminescent device and display element

Abstract

The invention discloses a compound containing pyrimidine and oxa-spirofluorene structures, an organic electroluminescent device and a display element, and belongs to the technical field of semiconductor materials. The structure of the compound is shown as a general formula (1): # imgabs0 #, the organic electroluminescent device comprises a substrate, a first electrode and a second electrode, a plurality of organic thin film layers are arranged between the first electrode and the second electrode, and the organic thin film layers contain the compound containing the pyrimidine and oxa spirofluorene structure. The organic thin film layer comprises a hole transport region thin film layer, a light-emitting region thin film layer and an electron transport region thin film layer, and the electron transport region thin film layer contains the compound containing the pyrimidine and oxa spirofluorene structure. The compound containing pyrimidine and oxa-spirofluorene structures has good stability and good hole blocking capability, and when the compound is used as a material of an organic electroluminescent device, the efficiency of the device is remarkably improved, and the service life of the device is remarkably prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor materials, and in particular to a compound containing pyrimidine and oxaspirofluorene structures, an organic electroluminescent device and a display element. Background Art

[0002] Organic light-emitting diode (OLED) technology can be used to manufacture new display products as well as new lighting products. It is expected to replace existing liquid crystal displays and fluorescent lighting, and has a wide range of applications. Organic light-emitting diodes have a sandwich-like structure, including electrode material films and organic photoelectric functional materials sandwiched between different electrode material films. Various organic functional materials are superimposed on each other according to their uses to form organic light-emitting diodes. As a current device, when voltage is applied to the electrodes at both ends of the organic light-emitting diode and the electric field acts on the positive and negative charges in the organic photoelectric functional material film layer, the positive and negative charges further recombine in the light-emitting layer, generating organic electroluminescence.

[0003] Currently, organic electroluminescent device display technology has been applied in smart phones, tablet computers, TVs and other fields. However, compared with the actual product application requirements, the performance of organic electroluminescent devices such as luminous efficiency and service life needs to be further improved. In order to continuously improve the performance of organic electroluminescent devices, it is necessary to continuously research and innovate organic optoelectronic functional materials to create higher performance organic optoelectronic functional materials.

[0004] Organic optoelectronic functional materials used in organic electroluminescent devices can be divided into two categories based on their uses, namely charge injection and transport materials and luminescent materials. Furthermore, charge injection and transport materials can be divided into electron injection and transport materials, electron blocking materials, hole injection and transport materials, and hole blocking materials. For organic electroluminescent devices, holes are injected from the anode, electrons are injected from the cathode, and are transported in the organic functional layer, and finally meet in the luminescent layer to form excitons, which recombine and emit light. The hole blocking layer is located between the luminescent layer and the electron transport layer, which can block the diffusion or movement of holes to the electron transport layer, and can also reduce the energy loss of excitons, playing a role in interface modification and auxiliary regulation of electron injection / transport. Due to the poor electron regulation ability and hole and exciton blocking ability of the existing hole blocking layer materials, it is difficult to obtain an efficient electron-hole balance inside the light-emitting layer, and it is difficult to obtain high-efficiency and long-life devices. At the same time, the existing hole blocking layer materials also have a narrow heat resistance window and poor electron tolerance. Therefore, it is necessary to further improve the electron injection and transmission capabilities of the hole blocking layer materials, the hole and exciton blocking ability, improve the stability of the material, achieve an efficient balance of excitons, and improve the efficiency and life of the device. Summary of the invention

[0005] In view of the above problems existing in the prior art, the present invention provides a compound containing pyrimidine and oxyspirofluorene structures, an organic electroluminescent device, and a display element. The compound of the present invention is bridged by a specific structure, and the substituent group is oxyspirofluorene at a specific site, so that the compound has excellent hole blocking ability and good material stability. When applied to organic electroluminescent devices, the luminous efficiency and service life of the device can be effectively improved.

[0006] A compound containing pyrimidine and oxaspirofluorene structures, wherein the structure of the compound is shown in general formula (1):

[0007]

[0008] In the general formula (1), X1, X2, X3, X4, X5, and X6 are each independently CH or N, wherein only two of X1, X2, and X3 are N; X1, X2, X3, X4, X5, and X6 may be the same or different;

[0009] Ar1 and Ar2 are each independently substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophenyl, or substituted or unsubstituted carbazolyl;

[0010] R2 represents any one of substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted pyridyl, or substituted or unsubstituted pyrimidinyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophenyl, substituted or substituted carbazolyl, or substituted or substituted N-phenylcarbazolyl;

[0011] L1 represents any one of a single bond, a substituted or unsubstituted phenylene group, a substituted or unsubstituted naphthylene group, and a substituted or unsubstituted pyridylene group;

[0012] R1 is represented by the general formula (2); any unsubstituted carbon on the benzene ring in the general formula (2) can serve as a connection site with the general formula (1);

[0013] X represents any one of an oxygen atom, a sulfur atom or a dimethyl-substituted methylene group;

[0014] R3 and R4 are each independently a hydrogen atom, a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, or a substituted or unsubstituted pyridyl group;

[0015] In the general formula (1), * indicates the connection position;

[0016] The substituents for replacing the above substitutable groups are selected from halogen, deuterium, phenyl, biphenyl, naphthyl, pyridyl, pyrimidyl, and phenanthryl.

[0017] Furthermore, the structure of the compound is shown in any one of general formulas (3) to (8):

[0018]

[0019] In the general formulae (3) to (8), Ar1, Ar2, R1, R2, L1, X1, X2, X3, X4, X5, and X6 have the same meanings as defined above.

[0020] Furthermore, in the general formula (1), R1 is independently selected from any one of the following structures:

[0021]

[0022] X, R3, and R4 have the same meanings as defined above;

[0023] Further, the R1 is independently selected from any one of the following structures:

[0024]

[0025] Further, the R1 is independently selected from any one of the following structures:

[0026]

[0027] Furthermore, in the general formula (1), Ar1 and Ar2 are independently selected from any one of the following structures:

[0028] The R2 is independently selected from any one of the following structures:

[0029] Furthermore, the specific structure of the compound is any one of the following structures:

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051] The invention also discloses an organic electroluminescent device, comprising a substrate, a first electrode and a second electrode, wherein a plurality of organic thin film layers are provided between the first electrode and the second electrode, and the organic thin film layers contain the compound containing pyrimidine and oxaspirofluorene structure of the invention.

[0052] Furthermore, the organic thin film layer includes a hole transport region thin film layer, a light emitting region thin film layer and an electron transport region thin film layer, and the electron transport region thin film layer contains the compound containing pyrimidine and oxaspirofluorene structure of the present invention.

[0053] Furthermore, the electron transport region thin film layer comprises a hole blocking layer, and the hole blocking layer contains the compound containing pyrimidine and oxaspirofluorene structure of the present invention.

[0054] Furthermore, the hole transport region thin film layer comprises a hole injection layer, a hole transport layer and an electron blocking layer, the electron transport region thin film layer comprises a hole blocking layer, an electron transport layer and an electron injection layer, and the hole blocking layer contains the compound containing pyrimidine and oxaspirofluorene structure described in the present invention.

[0055] The invention also discloses a display element, which contains the organic electroluminescent device of the invention.

[0056] The beneficial technical effects of the present invention are:

[0057] The connection mode of pyrimidine and oxaspirofluorene in the structure of the pyrimidine and oxaspirofluorene-containing compound of the present invention is fixed as 1, 3, and 4-position bridging, so that the compound containing pyrimidine and oxaspirofluorene structure of the present invention has more excellent hole blocking and exciton blocking capabilities, can effectively block holes from diffusing or moving to the electron transport layer, so that the holes are better confined in the light-emitting area, ensuring that more hole electrons in the light-emitting layer form excitons, increasing the exciton concentration, and thus improving the light-emitting efficiency and device life.

[0058] The structural characteristics of the compounds containing pyrimidine and oxyspirofluorene structures described in the present invention enable the compounds containing pyrimidine and oxyspirofluorene structures described in the present invention to have more excellent electron regulation ability, supplement the electron transport layer, enhance or delay electron injection and transport according to the electron-hole balance inside the light-emitting layer, and enhance the luminous efficiency and device life of the device.

[0059] The compound containing pyrimidine and oxaspirofluorene structure of the present invention has a lower evaporation temperature and chemical stability, so that the evaporation film thereof has good film phase stability and a wider heat resistance window, thereby ensuring the stability in device manufacturing and product use. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 Schematic diagram of the structure of the OLED device described in the embodiment.

[0061] In the figure, 1, transparent substrate layer; 2, anode layer; 3, hole injection layer; 4, hole transport layer; 5, electron blocking layer; 6, light-emitting layer; 7, hole blocking layer; 8, electron transport layer; 9, electron injection layer; 10, cathode layer; 11, light extraction layer. DETAILED DESCRIPTION

[0062] The technical solution of the present invention will be described in detail below in conjunction with the implementation scheme.

[0063] In the present invention, unless otherwise specified, HOMO means the highest occupied orbital of a molecule, and LUMO means the lowest unoccupied orbital of a molecule. In addition, in the present invention, HOMO and LUMO energy levels are expressed in absolute values, and the comparison between energy levels is also a comparison of the magnitude of their absolute values. Those skilled in the art know that the greater the absolute value of an energy level, the lower the energy of the energy level.

[0064] In the drawings, the sizes 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, the layer or element may be directly on the other layer or substrate, or intervening layers may also be present. In addition, it will be understood that when a layer is referred to as being "between" two layers, the layer may be the only layer between the two layers, or one or more intervening layers may also be present.

[0065] In the present invention, when describing electrodes and organic electroluminescent devices, as well as other structures, the words "upper" and "lower" used to indicate orientation only indicate orientation in a certain state, and do not mean that the related structure can only exist in the orientation described; on the contrary, if the structure can change its position, such as inverted, the orientation of the structure will be changed accordingly. Specifically, in the present invention, the "lower" side of the electrode refers to the side of the electrode close to the substrate during the preparation process, and the opposite side away from the substrate is the "upper" side.

[0066] Organic electroluminescent devices

[0067] The organic electroluminescent device of the present invention may be a bottom-emitting organic electroluminescent device, a top-emitting organic electroluminescent device or a stacked organic electroluminescent device, and there is no particular limitation on this.

[0068] The organic electroluminescent device of the present invention comprises a substrate, a first electrode, a multi-layer organic thin film layer and a second electrode. The multi-layer organic thin film layer comprises a hole transport region, a light-emitting layer and an electron transport region, the hole transport region comprises a hole injection layer, a hole transport layer and an electron blocking layer, the electron transport region comprises a hole blocking layer, an electron transport layer and an electron injection layer, and a covering layer may be provided on the second electrode.

[0069] The organic electroluminescent device of the present invention may include layers and the positional relationship of each layer is as follows: it may include a substrate, a first electrode, 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, a second electrode and a covering layer. If the above layers exist, the first electrode is above the substrate, the hole injection layer is above the first electrode, the hole transport layer is above the hole injection layer, the electron blocking layer is above the hole transport layer, the light-emitting layer is above the electron blocking layer, the hole blocking layer is above the light-emitting layer, the electron transport layer is above the hole blocking layer, the electron injection layer is above the electron transport layer, the second electrode is above the electron injection layer, and the covering layer is above the second electrode.

[0070] As the substrate of the organic electroluminescent device of the present invention, any substrate commonly used in organic electroluminescent devices can be used. Examples are transparent substrates, such as glass or transparent plastic substrates; opaque substrates, such as silicon substrates; flexible PI film substrates. Different substrates have different mechanical strengths, thermal stability, transparency, surface smoothness, and waterproofness. Depending on the properties of the substrate, its use direction is different. In the present invention, a transparent glass substrate is preferably used, and the thickness of the substrate is not particularly limited.

[0071] A first electrode is formed on a 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. In the present invention, the first electrode is used as an anode, and the anode material is preferably a material with 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 (SnO2), 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 multilayer structure including two or more layers. In addition, the thickness of the anode depends on the material used, typically 50-500nm, preferably 70-300nm and more preferably 100-200nm.

[0072] A hole injection layer, a hole transport layer, and an electron blocking layer may be disposed between the first electrode and the light emitting layer.

[0073] The hole injection layer may include a main material and a P-type doping material, wherein the main material may be selected from conventional hole transport materials in the prior art, preferably the same organic material as the hole transport layer, and the P-type doping material is selected from compounds with charge conductivity disclosed in the prior art, and may be selected from compounds disclosed in the following patent documents: WO2011073149A, EP1968131A1, EP2276085A1, EP2213662A1, EP1722602A1, EP2 045848A1, DE102007031220A1, US20100181555A1, US20100102709A1, WO2009003455A1, WO2010094378A1, WO2011120709A1, US20100096600A1, DE102012209523A1, CN101728485A and WO2012095143A1, but are not limited thereto.

[0074] For example, the compound shown below:

[0075]

[0076] According to the present invention, P1 is preferably used as the P-type doping material.

[0077] The thickness of the hole injection layer of the present invention may be 1-100 nm, preferably 2-50 nm, and more preferably 5-20 nm.

[0078] 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.

[0079] Preferably, the hole transport layer material of the present invention may be selected from the following compounds disclosed in the prior art:

[0080]

[0081] The thickness of the hole transport layer of the present invention may be 5-200 nm, preferably 10-180 nm, and more preferably 20-150 nm.

[0082] 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 material in the light-emitting layer, which 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 main material of the light-emitting layer, which is conducive to the injection of holes from the positive electrode into the light-emitting layer. At the same time, the electron blocking layer material is required to have a high hole mobility, which is conducive to hole transport and reduces the application power of the device; the LUMO energy level of the electron blocking layer material is higher than the LUMO energy level of the main material of the light-emitting layer, which plays a role in electron blocking, that is, the electron blocking layer material is required to have a wide bandgap width (Eg). The electron blocking layer materials that meet the above conditions can be triarylamine derivatives, fluorene derivatives, oxaspirofluorene derivatives, dibenzofuran derivatives, carbazole derivatives, etc.

[0083] In one embodiment of the present invention, the electron blocking layer material of the present invention may be selected from the following compounds disclosed in the prior art:

[0084]

[0085] According to the present invention, the thickness of the electron blocking layer may be 1-200 nm, preferably 5-150 nm, and more preferably 5-50 nm.

[0086] According to the present invention, the light-emitting layer is located between the electron blocking layer and the hole blocking layer, and the material of the light-emitting layer is a material that can emit visible light by receiving holes from the hole transport region and electrons from the electron transport region respectively, and combining the received holes and electrons. The light-emitting layer may include a host material and a doping material. As the host material and guest material of the light-emitting layer of the organic electroluminescent device of the present invention, the host material may be one or a combination of two of anthracene derivatives, quinoxaline derivatives, triazine derivatives, xanthone derivatives, diphenyl ketone derivatives, carbazole derivatives, pyridine derivatives or pyrimidine derivatives. The guest material may be a pyrene derivative, a boron derivative, a chrysene derivative, an oxaspirofluorene derivative, an iridium complex or a platinum complex.

[0087] The thickness of the light-emitting layer of the present invention may be 5-60 nm, preferably 10-50 nm, and more preferably 20-45 nm.

[0088] The hole blocking layer can be arranged on 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 main material of the light-emitting layer, which can play a role in blocking the energy loss of the light-emitting layer material; the HOMO energy level of the material is lower than the HOMO energy level of the main material of the light-emitting layer, which plays a role in hole blocking. At the same time, the hole blocking layer material is required to have a high electron mobility, which is conducive to electron transmission and reduces the application power of the device; the hole blocking layer material that meets the above conditions is the compound described above in the present invention.

[0089] The thickness of the hole blocking layer of the present invention may be 2-200 nm, preferably 5-150 nm, and more preferably 5-50 nm, but the thickness is not limited to this range.

[0090] The electron transport layer may be disposed on the light-emitting layer or (if present) the hole blocking layer. The electron transport layer material is a material that easily receives electrons from the cathode and transfers the received electrons to the light-emitting layer. A material having a high electron mobility is preferred. As the electron transport layer of the organic electroluminescent device of the present invention, the following compounds disclosed in the prior art can be used as electron transport layer materials for organic electroluminescent devices:

[0091]

[0092] In a preferred embodiment of the present invention, the electron transport layer further comprises other compounds conventionally used in electron transport layers, for example, Alq3, LiQ, preferably LiQ.

[0093] The thickness of the electron transport layer of the present invention may be 10-80 nm, preferably 20-60 nm, and more preferably 25-45 nm.

[0094] According to the present invention, the electron injection layer can be arranged between the electron transport layer and the cathode. The electron injection layer material is generally preferably a material with a low work function, so that electrons are easily injected into the organic functional material layer. Preferably, the electron injection layer material is an N-type metal material. As the electron injection layer material of the organic electroluminescent device of the present invention, the electron injection layer materials for organic electroluminescent devices disclosed in the following prior art can be used: LiF, Cs2CO3, CsF, Csq, NaF, MgF2, CaF2, Al2O3, Yb.

[0095] The thickness of the electron injection layer of the present invention may be 0.1-5 nm, preferably 0.5-3 nm, and more preferably 0.8-1.5 nm, but the thickness is not limited to this range.

[0096] According to the present invention, as mentioned above, the second electrode can be a cathode or an anode. In the present invention, the second electrode is used as a cathode. The material used to form the cathode can be a material with a low work function, such as a metal, an alloy, a conductive compound or a mixture thereof. Non-limiting examples of cathode materials can 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 depends on the material used, typically 5-100nm, preferably 7-50nm, and more preferably 10-25nm.

[0097] Optionally, in order to improve the light extraction efficiency of the organic electroluminescent device, a light extraction layer (ie, CPL layer) may be added on the second electrode (ie, cathode) of the device. The following compounds disclosed in the prior art may be used as CPL layer materials.

[0098]

[0099]

[0100] The thickness of the CPL layer is generally 5-300 nm, preferably 20-100 nm, and more preferably 40-80 nm.

[0101] The organic electroluminescent device may further include an encapsulation structure. The encapsulation structure may be a protective structure that prevents foreign substances such as moisture and oxygen from entering the organic 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.

[0102] Organic electroluminescent device preparation method

[0103] The present invention also relates to a method for preparing the above-mentioned organic electroluminescent device, which comprises laminating a first electrode, a multi-layer organic thin film layer and a second electrode on a substrate in sequence. The multi-layer organic thin film layer is formed by laminating a hole transport region, a light-emitting layer and a hole blocking region on the first electrode from bottom to top, and the hole transport region is formed by laminating a hole injection layer, a hole transport layer and an electron blocking layer on the first electrode in sequence from bottom to top, and the hole blocking region is formed by laminating a hole blocking layer, an electron transport layer and an electron injection layer on the light-emitting layer in sequence from bottom to top. In addition, optionally, a CPL layer can also be laminated on the second electrode to improve the light extraction efficiency of the organic electroluminescent device.

[0104] For lamination, vacuum deposition, vacuum evaporation, spin coating, casting, LB method, inkjet printing, laser printing or LITI methods may be used, but are not limited thereto. Vacuum evaporation means heating and coating a material onto a substrate in a vacuum environment.

[0105] In the present invention, the various layers are preferably formed by vacuum evaporation, wherein the layers can be formed at a temperature of about 100-500° C. and at a temperature of about 10 -8 -10 -2 Torr vacuum and approx. The vacuum evaporation is carried out at a rate of 10 -6 -10 -2 Torr, preferably 10 -5 -10 -3 Torr. The rate is More preferably

[0106] In addition, it should be noted that the materials used to form each layer described in the present invention can be formed into a film alone and used as a single layer, or can be mixed with other materials to form a film and used as a single layer. It can also be a stacked structure between layers formed into films alone, a stacked structure between layers formed into films after mixing, or a stacked structure of layers formed into films alone and layers formed into films after mixing.

[0107] Display components

[0108] The present invention also relates to a display device including the above-mentioned organic electroluminescent device, in particular a flat panel display device. In a preferred embodiment, the display device may include one or more of the above-mentioned organic electroluminescent devices, and in the case of including a plurality of devices, the devices are stacked and combined laterally or longitudinally. The display device may also include at least one thin film transistor. The thin film transistor may include a gate electrode, a source electrode and a drain electrode, a gate insulating layer and an active layer, wherein one of the source electrode and the drain electrode may be electrically connected to the 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.

[0109] The following examples are intended to better explain the present invention, but the scope of the present invention is not limited thereto.

[0110] Example

[0111] I. Compound Preparation Examples

[0112] The present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

[0113] The raw materials involved in the synthesis examples of the present invention can be purchased from the market or prepared by conventional preparation methods in the art (references are given).

[0114] Preparation of intermediate B12:

[0115]

[0116] Under nitrogen protection, in a round-bottom flask, raw material O12 (8.41 g, 30 mmol), raw material P12 (9.52 g, 30 mmol), K2CO3 (13.82 g, 100 mmol), tetrahydrofuran (160 mL), and water (60 mL) were added in sequence, and nitrogen was passed through for 50 min to replace the air. Pd(PPh3)4 (0.69 g, 0.6 mmol) was added, and the mixture was heated to reflux for 16 h under nitrogen protection. The reaction solution was taken for TCL detection and it was found that the raw material P12 had reacted completely. After the reaction was completed, the reaction system was naturally cooled to room temperature, the solvent was removed by rotary evaporation, 150 ml of dichloromethane was added to the residue to dissolve, 140 ml of water was added to wash, poured into a separatory funnel and shaken, and then allowed to stand for stratification. After separation, the aqueous phase was extracted with dichloromethane (60 ml*3), the organic phases were combined and dried with anhydrous magnesium sulfate, filtered, and the filtrate was subjected to rotary evaporation to remove dichloromethane to obtain a crude product, which was purified by silica gel column chromatography to obtain intermediate B12. LC-MS: Measured value: 342.88 ([M+H] + ), exact mass: 341.98.

[0117] Preparation of intermediate C3:

[0118]

[0119] Under nitrogen protection, in a round-bottom flask, raw material A3 (10.75 g, 30 mmol), raw material B3 (8.03 g, 30 mmol), K2CO3 (13.82 g, 100 mmol), tetrahydrofuran (150 mL), water (60 mL) were added in sequence, nitrogen was passed for 60 min to replace the air, Pd (PPh3) 4 (0.69 g, 0.6 mmol) was added, and the mixture was heated under reflux for 16 h under nitrogen protection. TCL detection of the reaction solution showed that the raw material A3 reacted completely. After the reaction was completed, the reaction system was naturally cooled to room temperature, the solvent was removed by rotary evaporation, 140 ml of dichloromethane was added to the residue to dissolve, 120 ml of water was added to wash, poured into a separating funnel and shaken, and then allowed to stand for stratification. After separation, the aqueous phase was extracted with dichloromethane (60 ml * 3), the organic phases were combined and dried with anhydrous magnesium sulfate, filtered, and the filtrate was subjected to rotary evaporation to remove dichloromethane to obtain a crude product, which was purified by silica gel column chromatography to obtain intermediate C3.

[0120] Preparation of intermediate C13:

[0121]

[0122] Under nitrogen protection, in a round-bottom flask, raw material B13 (12.57 g, 30 mmol), raw material A13 (7.62 g, 30 mmol), KOAC (4.91 g, 50 mmol), dioxane (120 ml), water (120 ml) were added in sequence, nitrogen was passed for 60 min to replace the air, Pd (dppf) Cl2 (0.22 g, 0.3 mmol) was added, and the mixture was heated under reflux for 15 h under nitrogen protection. TCL detection of the reaction solution showed that the raw material B13 reacted completely. After the reaction was completed, the reaction system was naturally cooled to room temperature, the solvent was removed by rotary evaporation, 140 ml of dichloromethane was added to the residue to dissolve, 120 ml of water was added to wash, poured into a separating funnel and shaken, and then allowed to stand for stratification. After separation, the aqueous phase was extracted with dichloromethane (50 ml * 3), the organic phases were combined and dried with anhydrous magnesium sulfate, filtered, and the filtrate was subjected to rotary evaporation to remove dichloromethane to obtain intermediate C13. LC-MS: Found: 511.29 ([M+H] + ), exact mass: 510.25.

[0123] Intermediate C was prepared by the synthesis method of intermediate C3, except that different raw materials were used, as shown in Table 1.

[0124] Table 1

[0125]

[0126]

[0127] Example 1: Synthesis of Compound 1

[0128]

[0129] Under nitrogen protection, in a round-bottom flask, raw material C1 (4.19 g, 10 mmol), raw material D1 (5.50 g, 12 mmol), K2CO3 (4.15 g, 30 mmol), tetrahydrofuran (50 mL), water (40 mL) were added in sequence, nitrogen was passed through for 50 min to replace the air, palladium acetate (0.0225 g, 0.10 mmol), 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (0.0954 g, 0.20 mmol) were added, and the mixture was heated to reflux for 29 h under nitrogen protection. The reaction solution was taken for TCL detection, and it was found that the raw material C1 had reacted completely. After the reaction was completed, the reaction system was naturally cooled to room temperature, the solvent was removed by rotary evaporation, 180 ml of dichloromethane was added to the residue to dissolve, 120 ml of water was added to wash, poured into a separatory funnel and shaken, and then allowed to stand for stratification. After separation, the aqueous phase was extracted with dichloromethane (80 ml*3), the organic phases were combined and dried with anhydrous magnesium sulfate, filtered, and the filtrate was evaporated to remove dichloromethane to obtain a crude product, which was purified by silica gel chromatography to obtain compound 1.

[0130] Other compounds were prepared by a synthetic method similar to compound 1, except that different reactants were replaced. The raw materials or intermediates used are shown in Table 2:

[0131] Table 2

[0132]

[0133]

[0134]

[0135]

[0136]

[0137] II. Device Preparation Example

[0138] The following describes in detail the application effect of the compound synthesized according to the present invention as a hole blocking layer material in the device through device examples 1-19 and device comparative examples 1-16. Compared with device comparative examples 1-16, device examples 1-19 have the same manufacturing process of the device, and use the same substrate material and electrode material, and the film thickness of the electrode material is also the same. The difference is that the hole blocking layer material in the device has changed. The device layer structure is shown in Table 3, and the performance test results of each device are shown in Table 4.

[0139] The molecular structure formula of the relevant materials is shown below:

[0140]

[0141]

[0142] The structures of comparative compounds HB-1, HB-2, HB-3, HB-4, HB-5, HB-6, HB-7, HB-8, HB-9, HB-10, HB-11, HB-12, HB-13, HB-14, HB-15 and HB-16 are shown above. The above materials can be purchased commercially or prepared by the synthesis methods described in the prior art.

[0143] Device Comparison Example 1

[0144] The specific preparation process is as follows:

[0145] like Figure 1As shown, the transparent substrate layer 1 is transparent glass, and Ag (100nm) is evaporated as the anode layer 2. On the anode layer 2, a vacuum evaporation device is used to evaporate HT-1 and P-1 with a film thickness of 10nm as the hole injection layer 3, and the mass ratio of HT-1 and P-1 is 97:3. Then, HT-1 with a thickness of 130nm is evaporated as the hole transport layer 4. Then, EB-1 with a thickness of 5nm is evaporated as the electron blocking layer 5. After the above-mentioned electron blocking material is evaporated, the light-emitting layer 6 of the OLED light-emitting device is prepared, using BH-1 as the main material and BD-1 as the doping material. The doping ratio of the doping material is 3% by weight, and the thickness of the light-emitting layer is 20nm. After the above-mentioned light-emitting layer 6, HB-1 is continuously evaporated, and the evaporated film thickness is 5nm, as the hole blocking layer 7. On the above-mentioned hole blocking layer 7, ET-1 and LiQ are continuously evaporated, and the mass ratio of ET-1 and LiQ is 1:1. The vacuum evaporated film thickness of this material is 30nm, and this layer is the electron transport layer 8. On the electron transport layer 8, a LiF layer with a thickness of 1 nm was formed by a vacuum evaporation device, and this layer was the electron injection layer 9. On the electron injection layer 9, a Mg:Ag electrode layer with a thickness of 16 nm was formed by a vacuum evaporation device, and the mass ratio of Mg to Ag was 1:9, and this layer was used as the cathode layer 10. On the cathode layer 10, 65 nm of CP-1 was vacuum evaporated as the light extraction layer 11.

[0146] Device Examples 1-19 and Device Comparative Examples 2-16 were prepared in a similar manner to Device Comparative Example 1, except that the hole blocking layer materials in Table 3 below were used.

[0147] Table 3

[0148]

[0149]

[0150]

[0151] III. Device Testing Example

[0152] The device prepared in II was tested for its current efficiency, CIEy and LT95 life. The current efficiency and CIEy were tested using an IVL (current-voltage-luminance) test system (Suzhou Fushida Scientific Instrument Co., Ltd.) at a current density of 10 mA / cm 2 LT95 refers to the time it takes for the device brightness to decay to 95% of the initial brightness. The current density during the test is 30mA / cm 2 ; The life test system is the EAS-62C OLED device life tester produced by Japan System Engineering Co., Ltd.; The test results are shown in Table 4 below.

[0153] Table 4

[0154]

[0155]

[0156]

[0157] It can be seen from the device test data results in Table 4 above that compared with the comparative devices using HB-1, HB-2, HB-3, HB-4, HB-5, HB-6, HB-7, HB-8, HB-9, HB-10, HB-11, HB-12, HB-13, HB-14, HB-15 and HB-16 as hole blocking layer materials, the device current efficiency prepared using the compounds of the present invention as hole blocking layer materials is improved and the device life is extended. For example, its life is substantially more than 1.2 times that of comparative devices 1-9.

[0158] The structural formulas of the comparative compounds HB-1, HB-2, HB-3, HB-4, HB-5, HB-6, HB-7, HB-8, HB-9, HB-10, HB-11, HB-12, HB-13, HB-14, HB-15 and HB-16 used in the comparative examples are close to those of the present invention, for example, only the connection positions are different. However, the compounds of the present invention achieve better technical effects as hole blocking layer materials than the comparative compounds.

[0159] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A compound containing pyrimidine and oxaspirofluorene structure, characterized in that: The structure of the compound is shown in general formula (1): In the general formula (1), X1, X2, X3, X4, X5, and X6 are each independently CH or N, wherein only two of X1, X2, and X3 are N; X1, X2, X3, X4, X5, and X6 may be the same or different; Ar1 and Ar2 are each independently substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophenyl, or substituted or unsubstituted carbazolyl; R2 represents any one of substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted pyridyl, or substituted or unsubstituted pyrimidinyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophenyl, substituted or substituted carbazolyl, or substituted or substituted N-phenylcarbazolyl; L1 represents any one of a single bond, a substituted or unsubstituted phenylene group, a substituted or unsubstituted naphthylene group, and a substituted or unsubstituted pyridylene group; R1 is represented by the general formula (2); any unsubstituted carbon on the benzene ring in the general formula (2) can serve as a connection site with the general formula (1); X represents any one of an oxygen atom, a sulfur atom or a dimethyl-substituted methylene group; R3 and R4 are each independently a hydrogen atom, a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, or a substituted or unsubstituted pyridyl group; In the general formula (1), * indicates the connection position; The substituents for replacing the above substitutable groups are selected from halogen, deuterium, phenyl, biphenyl, naphthyl, pyridyl, pyrimidyl, and phenanthryl.

2. A compound containing pyrimidine and oxaspirofluorene structure according to claim 1, characterized in that: The structure of the compound is shown in any one of the general formulas (3) to (8): In general formula (3) to general formula (8), Ar1, Ar2, R1, R2, L1, X1, X2, X3, X4, X5, and X6 have the same meanings as defined in claim 1.

3. A compound containing pyrimidine and oxaspirofluorene structure according to claim 1, characterized in that: In the general formula (1), R1 is independently selected from any one of the following structures: X, R3, and R4 have the same meanings as those defined in claim 1; Preferably, the R1 is independently selected from any one of the following structures: Preferably, the R1 is independently selected from any one of the following structures:

4. The compound containing pyrimidine and oxaspirofluorene structure according to claim 1, characterized in that: In the general formula (1), Ar1 and Ar2 are independently selected from any one of the following structures: The R2 is independently selected from any one of the following structures:

5. The compound containing pyrimidine and oxaspirofluorene structure according to claim 1, characterized in that: The specific structure of the compound is any one of the following structures:

6. An organic electroluminescent device comprising a substrate, a first electrode and a second electrode, wherein a plurality of organic thin film layers are provided between the first electrode and the second electrode, wherein: The organic thin film layer contains the compound containing pyrimidine and oxaspirofluorene structure according to any one of claims 1 to 5.

7. An organic electroluminescent device according to claim 6, characterized in that: The organic thin film layer comprises a hole transport region thin film layer, a light emitting region thin film layer and an electron transport region thin film layer, and the electron transport region thin film layer contains the compound containing pyrimidine and oxaspirofluorene structure according to any one of claims 1 to 5.

8. An organic electroluminescent device according to claim 7, characterized in that: The electron transport region thin film layer comprises a hole blocking layer, and the hole blocking layer contains the compound containing pyrimidine and oxaspirofluorene structure according to any one of claims 1 to 5.

9. An organic electroluminescent device according to claim 7, characterized in that: The hole transport region thin film layer comprises a hole injection layer, a hole transport layer and an electron blocking layer, the electron transport region thin film layer comprises a hole blocking layer, an electron transport layer and an electron injection layer, and the hole blocking layer contains the compound containing pyrimidine and oxaspirofluorene structure according to any one of claims 1 to 5.

10. A display element, characterized in that: The display element comprises the organic electroluminescent device according to any one of claims 6 to 9.

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