A blue organic electroluminescent device and its application

Abstract

The present invention discloses a blue organic electroluminescent device, comprising: a substrate layer; a first electrode on the substrate layer; an organic light-emitting functional layer on the first electrode; a second electrode on the organic light-emitting functional layer; and a cover layer on the second electrode; the organic light-emitting functional layer includes a hole injection layer formed by a hole transport material represented by General Formula (3) or General Formula (4) and a P-type doping material represented by General Formula (1) or General Formula (2), a hole transport layer represented by General Formula (3) or General Formula (4), an electron blocking layer represented by General Formula (5), and a light-emitting layer composed of a first compound selected from General Formula (6) and a doping material represented by General Formula (7) or General Formula (8). The device combination of the present invention can achieve high color purity of the device, reduce the device voltage, and improve the device efficiency and lifespan.

Description

Technical Field

[0001] The present invention relates to an organic electroluminescent device, and more particularly to a blue organic electroluminescent device having improved device luminous efficiency, reduced device driving voltage, and improved device lifetime, and its applications. Background Art

[0002] The technology of organic electroluminescent (OLED: Organic Light Emission Diodes) devices can be used to manufacture new display products and can also be used to make new lighting products. It is expected to replace existing liquid crystal displays and fluorescent lamp lighting, and has a very broad application prospect. The OLED light-emitting device has a structure like a sandwich, including electrode material film layers and organic functional materials sandwiched between different electrode film layers. Various different functional materials are stacked together according to their uses to jointly form an OLED light-emitting device. As a current device, when a voltage is applied to the two electrodes of the OLED light-emitting device and positive and negative charges in the organic layer functional material film layer act through an electric field, the positive and negative charges further recombine in the light-emitting layer, that is, OLED electroluminescence is generated.

[0003] The OLED optoelectronic functional material film layer constituting the OLED device includes at least two or more structures. The OLED device structure applied industrially includes a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and other film layers. That is to say, the optoelectronic functional materials applied to the OLED device include at least hole injection materials, hole transport materials, light-emitting materials, electron transport materials, etc. The material types and matching forms have the characteristics of richness and diversity.

[0004] In the OLED light-emitting device, positive charges are injected from the anode, negative charges are injected from the cathode, and negative and positive charge carriers recombine in the light-emitting layer of the device to form two excited states: intermolecular negative charge-positive charge pairs (polaron pairs) and intramolecular negative charge-positive charge pairs (excitons). Based on the spin statistics principle, these excited states are further divided into singlet states and triplet states. Singlet excitons generate instantaneous fluorescence emission through radiative transitions, while the radiative recombination of triplet excitons is spin-forbidden and cannot directly participate in luminescence, but can couple with each other under certain conditions to generate singlet excitons, thereby forming delayed electroluminescence, that is, delayed luminescence, also called TTF-coupled luminescence. Theoretically, the internal quantum efficiency of a TTF fluorescent device can reach 62.5%, which is much higher than the internal quantum efficiency of 25% of traditional fluorescence, and this plays an important role in improving the efficiency of OLED light-emitting devices.

[0005] Necessary conditions for generating stable and efficient TTF-coupled luminescence based on a fluorescent host-guest material combination device include:

[0006] 1). The energy transfer between the host material and the dopant material conforms to the energy transfer law.

[0007] 2). The energy of the singlet exciton of the host material is close to twice the energy of the triplet exciton.

[0008] 3). The host and guest materials have appropriate energy level matching.

[0009] 4). Efficient injection of positive and negative charges into the light-emitting layer and good carrier balance.

[0010] Lifetime and efficiency are the biggest problems in organic light-emitting devices, and as the display size increases, these efficiency and lifetime problems must be solved. Efficiency, lifetime, and driving voltage are interrelated. As efficiency increases, the driving voltage decreases relatively. As the driving voltage decreases, the Joule heat generated during driving slows down the crystallization of organic materials, promoting the trend of lifetime improvement.

[0011] However, simply improving the organic material layer cannot maximize efficiency. This is because when the energy levels and T1 values between each organic material layer are optimally combined with the inherent properties of the material (mobility, interface properties, etc.), low voltage, long lifetime, and high efficiency can be achieved simultaneously.

[0012] In addition, to solve the light-emitting problem in the hole transport layer of recent organic light-emitting devices, an electron blocking layer must exist between the hole transport layer and the light-emitting layer; generally, electrons transfer from the electron transport layer to the light-emitting layer, and holes transfer from the hole transport layer to the light-emitting layer, and excitons are generated through recombination. However, in the case of the material used for the hole transport layer, since it must have a low HOMO value, most have a low T1 value, and this causes the excitons generated in the emission layer to transfer to the hole transport layer, resulting in charge imbalance in the emission layer. This leads to light emission at the hole transport layer interface. When light emission occurs at the hole transport layer interface, the color purity and efficiency of the organic electronic device deteriorate, and the lifetime is shortened.

[0013] Therefore, a reasonable device combination of the hole transport region and the light-emitting layer can effectively balance the exciton recombination region in the host, obtaining a higher-performance and more stable OLED device.

[0014] The hole transport region includes a hole injection layer, a hole transport layer, and an electron blocking layer. The hole injection layer needs to use a P-type material doped into the hole-type transport material to improve hole injection. For hole transport, the hole-type material is required to have a high mobility and form a complete charge transfer state with the P-type doped material, so that the final OLED device has high performance. In addition, the low mobility of the hole transport material is another obstacle restricting the performance improvement of the OLED device. In addition, the reasonable matching between the hole transport material and the electron blocking material seriously affects the efficiency and lifespan of the device. The electron blocking material not only requires a suitable HOMO energy level, but also requires strong electron blocking ability and exciton blocking ability.

[0015] Therefore, in view of the current industrial application requirements of OLED devices, the different functional film layers of OLED devices, and the optoelectronic property requirements of the devices, it is necessary to select more suitable and higher-performance OLED functional materials or material combinations to achieve the comprehensive characteristics of high efficiency, long lifespan, and low voltage of the devices. For TTF characteristic OLED light-emitting devices, in order to pursue a stable and efficient TTF light-emitting effect, certain requirements are imposed on the physical properties of the host-guest material combination. At the same time, it is necessary to have the best combination and matching form of the host-guest materials, good injection of carriers in the light-emitting layer, and good carrier balance. At the same time, it is required to be equipped with a hole transport region with high hole injection and hole transport, that is, an electron blocking layer material with high T1, high stability, and suitable HOMO / LUMO energy levels; a hole transport layer material with suitable T1, high stability, high mobility, and suitable HOMO energy levels; a hole injection layer material in which the hole transport material can form a complete charge transfer state with the P-type doped material. Summary of the Invention

[0016] In view of the above problems existing in the prior art, the applicant of the present invention provides a blue organic electroluminescent device and its application. The present invention uses a specific P-doped material to dope into the hole injection layer material, hole transport layer material, electron blocking layer material, and host-guest material of the light-emitting layer of the organic electroluminescent device, so that holes can be efficiently injected into the light-emitting layer, and holes and electrons can effectively recombine in the light-emitting layer to form excitons, promoting the device to achieve good luminous efficiency and lifespan at a lower voltage.

[0017] The technical solution of the present invention is as follows:

[0018] A blue organic electroluminescent device, which includes:

[0019] A substrate layer;

[0020] A first electrode, which is on the substrate layer;

[0021] An organic light-emitting functional layer, which is above the first electrode;

[0022] A second electrode, which is above the organic light-emitting functional layer;

[0023] And a cover layer, which is above the second electrode;

[0024] The organic light-emitting functional layer sequentially includes a hole injection layer, a hole transport layer, an electron blocking layer, and a light-emitting layer. The hole injection layer is adjacent to the first electrode, and the hole transport layer is located between the hole injection layer and the electron blocking layer. The electron blocking layer is located between the hole transport layer and the light-emitting layer. The hole injection layer is jointly formed by a hole transport material represented by general formula (3) or general formula (4) and a P-type doping material, and the P-type doping material is selected from compounds represented by general formula (1) or general formula (2); the hole transport layer contains a hole transport material represented by general formula (3) or general formula (4); the electron blocking layer contains a compound represented by general formula (5); the light-emitting layer contains a first compound and a doping material. The structure of the first compound is as shown in general formula (6). The doping material is selected from one of the compounds represented by general formula (7) or general formula (8), and the peak of the intrinsic emission spectrum of the doping material is between 450 and 470 nm;

[0025]

[0026] In general formula (1), each occurrence of R is independently selected from aryl or heteroaryl, and the aryl or heteroaryl is substituted or unsubstituted by an electron acceptor group;

[0027] In general formula (2), X and Y are each independently selected from CR”R”’, NR’, O, S, or Se; Z1 and Z2 are each independently selected from O, S, or Se;

[0028] In general formula (2), R1, R’, R”, and R”’ are the same or different each time they appear and are selected from hydrogen, deuterium, halogen, nitroso, nitro, acyl, carbonyl, carboxyl, ester, cyano, isocyano, -SCN, -OCN, -SF5, boranyl, sulfinyl, sulfonyl, phosphonyloxy, substituted or unsubstituted C 1-20 alkyl, substituted or unsubstituted C 3-20a cycloalkyl group, a substituted or unsubstituted heteroalkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 30 carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 20 carbon atoms, or a substituted or unsubstituted arylsilyl group having 6 to 20 carbon atoms; wherein at least one of R1, R', R", and R''' is a group having at least one electron-withdrawing group; adjacent substituents can optionally be linked to form a ring;

[0029] In general formula (3), R2, R3, R4, and R5 each independently represent a hydrogen atom, a protium atom, a deuterium atom, a tritium atom, a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, or a phenyl group; R2, R3, R4, and R5 may be the same as or different from each other; L represents a single bond, a phenylene group, a naphthylene group, or a biphenylene group; Ar1 and Ar2 each independently represent a substituted or unsubstituted C 6-50 aryl group or a substituted or unsubstituted heteroaryl group having 5 to 50 ring-forming atoms; Ar1 and Ar2 may be the same as or different from each other;

[0030] In general formula (4), A represents a single bond, any one of;

[0031] q represents 0 or 1; Ar3, Ar4, Ar5, Ar6, Ar7, and Ar8 each independently represent a substituted or unsubstituted C 6-50 aryl group or a substituted or unsubstituted heteroaryl group having 5 to 50 ring-forming atoms; Ar3 to Ar8 may be the same as or different from each other;

[0032] The dashed line indicates that the two groups are bonded by a single bond or not connected;

[0033] In general formula (5), g represents 0, 1 or 2; R6 and R7 each independently represent a hydrogen atom, a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted carbazolyl group or a substituted or unsubstituted dibenzofuranyl group. Preferably, R6 and R7 each independently represent a hydrogen atom, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl-substituted phenyl group, a naphthyl group, a carbazolyl group or a dibenzofuranyl group; R8 and R9 each independently represent a hydrogen atom, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a benzofuranyl group or a dibenzofuranyl group, and the connection modes of R8 and R9 with general formula (5) are two connection modes: annelation or single bond substitution;

[0034] L1 and L2 each independently represent a single bond, a phenylene group, a naphthylene group, a biphenylene group or a terphenylene group; L3 represents Ar9 and Ar 10 each independently represent a substituted or unsubstituted aryl group having C 6-50 or a substituted or unsubstituted heteroaryl group having 5-50 ring-forming atoms;

[0035] In general formula (6), a and e each independently represent 0, 1, 2 or 3; b, c, d and f each independently represent 0, 1, 2, 3 or 4; R 15 to R 20 each independently represent a hydrogen atom or a deuterium atom;

[0036] In general formula (7), R 11 and R 12 each independently represent a hydrogen atom, a protium atom, a deuterium atom, a tritium atom, a cyano group, a substituted or unsubstituted C 1-20 alkyl group, a substituted or unsubstituted C 3-20 cycloalkyl group, a substituted or unsubstituted alkoxy group having 1-20 carbon atoms, a substituted or unsubstituted aryl group having C 6-50 or a substituted or unsubstituted heteroaryl group having 5-50 ring-forming atoms;

[0037] Ar 11 and Ar 12 each time they appear the same or different, represent a substituted or unsubstituted aryl group having C 6-50 or a substituted or unsubstituted heteroaryl group having 5-50 ring-forming atoms;

[0038] In general formula (8), m, n and p each independently represent 0, 1, 2 or 3; A1, A2 and A3 each independently represent a substituted or unsubstituted C 6-50one of an aryl group, a substituted or unsubstituted heteroaryl group having 5 to 50 ring-forming atoms; Ra to Rb each independently represent a hydrogen atom, a protium atom, a deuterium atom, a tritium atom, a cyano group, a substituted or unsubstituted C 1-20 alkyl group, a substituted or unsubstituted C 3-20 cycloalkyl group, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted C 6-50 one of an aryl group, a substituted or unsubstituted heteroaryl group having 5 to 50 ring-forming atoms;

[0039] Rc to Re each independently represent a hydrogen atom, a protium atom, a deuterium atom, a tritium atom, a cyano group, a substituted or unsubstituted C 1-20 alkyl group, a substituted or unsubstituted C 3-20 cycloalkyl group, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted C 6-50 one of an aryl group, a substituted or unsubstituted heteroaryl group having 5 to 50 ring-forming atoms;

[0040] Between two adjacent Rc, two Rd or two Re, between Ra and Rc, Ra and Rd, Rb and Rc, Rb and Re, Rd and Re can also be bonded to each other to form a substituted or unsubstituted ring structure;

[0041] The substituents for the substituent groups are each independently selected from a deuterium atom, a halogen atom, a nitroso group, a nitro group, an acyl group, a carbonyl group, a carboxylic acid group, an ester group, an isocyano group, -SCN, -OCN, -SF5, a boranyl group, a sulfinyl group, a sulfonyl group, a phosphonyloxy group, C 1-10 alkoxy group, an adamantyl group, a cyano group, C 1-10 alkyl group, C 0-10 silyl group, C 3-20 cycloalkyl group, C 6-30 one of an aryl group, a 5- to 30-membered heteroaryl group containing one or more heteroatoms, wherein the heteroatoms are each independently selected from one or more of an oxygen atom, a sulfur atom, and a nitrogen atom.

[0042] In a preferred embodiment, the compound represented by the general formula (5) has a structure represented by any one of the general formulas (5-1) to (5-3):

[0043]

[0044] In the general formulas (5-1) to (5-3), the definitions of Ar9, Ar 10 , L1, L2, R6 to R9, and g are as described above.

[0045] Preferably, the structure of the doping material in the light-emitting layer is represented by any one of the general formulas (7-1) and (8-1):

[0046]

[0047] In general formula (7-1), Ar 11 and Ar 12 each occurrence, independently of one another, represents a substituted or unsubstituted aryl group having C 6-50 or a substituted or unsubstituted heteroaryl group having 5 to 50 ring-forming atoms;

[0048] In general formula (8-1), Z1 to Z 11 each independently represents CRc or a nitrogen atom; Ra and Rb each independently represent a substituted or unsubstituted C 1-20 alkyl group, a substituted or unsubstituted C 3-20 cycloalkyl group, a substituted or unsubstituted C 6-50 aryl group, or a substituted or unsubstituted heteroaryl group having 5 to 50 ring-forming atoms;

[0049] Rc represents a hydrogen atom, a deuterium atom, a tritium atom, a cyano group, a substituted or unsubstituted C 1-20 alkyl group, a substituted or unsubstituted C 3-20 cycloalkyl group, an amino group, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted C 6-50 aryl group, or a substituted or unsubstituted heteroaryl group having 5 to 50 ring-forming atoms; adjacent Ra, Rb, and Rc, and two adjacent Rc may also bond to each other to form a substituted or unsubstituted ring structure;

[0050] The substituents for the substituents are each independently selected from a deuterium atom, a halogen atom, a nitroso group, a nitro group, an acyl group, a carbonyl group, a carboxyl group, an ester group, an isocyano group, -SCN, -OCN, -SF5, a boranyl group, a sulfinyl group, a sulfonyl group, a phosphinyloxy group, a C 1-10 alkoxy group, an adamantyl group, a cyano group, a C 1-10 alkyl group, a C 0-10 silyl group, a C 3-20 cycloalkyl group, a C 6-30 aryl group, or a 5- to 30-membered heteroaryl group containing one or more heteroatoms, wherein the heteroatoms are each independently selected from one or more of an oxygen atom, a sulfur atom, and a nitrogen atom.

[0051] In a preferred embodiment, the Ar1, Ar2, Ar3, Ar4, Ar5, Ar6, Ar7, Ar8, Ar9, Ar 10 and Ar 11 and Ar 12Each is independently represented by one of a substituted or unsubstituted phenyl, a substituted or unsubstituted biphenyl, a substituted or unsubstituted naphthyl, a substituted or unsubstituted anthryl, a substituted or unsubstituted phenanthryl, a substituted or unsubstituted pyridyl, a substituted or unsubstituted pyrimidinyl, a substituted or unsubstituted pyrazinyl, a substituted or unsubstituted benzoxazolyl, a substituted or unsubstituted benzothiazolyl, a substituted or unsubstituted quinoxalinyl, a substituted or unsubstituted quinolinyl, a substituted or unsubstituted isoquinolinyl, a substituted or unsubstituted furyl, a substituted or unsubstituted thienyl, a substituted or unsubstituted indolyl, a substituted or unsubstituted pyrrolyl, a substituted or unsubstituted dibenzofuranyl, a substituted or unsubstituted dibenzothiophenyl, a substituted or unsubstituted 9,9-dimethylfluorenyl, a substituted or unsubstituted spirofluorene, a substituted or unsubstituted carbazolyl, a substituted or unsubstituted N-phenylcarbazolyl, a substituted or unsubstituted carbazolinyl, and a substituted or unsubstituted aza-phenanthrenyl;

[0052] Each of Ra and Rb is independently represented by one of a methyl, an ethyl, a propyl, an isopropyl, a tert-butyl, a butyl, a phenyl, a biphenyl, a naphthyl, an anthryl, a phenanthryl, a pyridyl, a pyrimidinyl, a pyrazinyl, a benzoxazolyl, a benzothiazolyl, a quinoxalinyl, a quinolinyl, an isoquinolinyl, a furyl, a thienyl, an indolyl, a pyrrolyl, a dibenzofuranyl, a dibenzothiophenyl, a 9,9-dimethylfluorenyl, a spirofluorene, a carbazolyl, an N-phenylcarbazolyl, a carbazolinyl, and an aza-phenanthrenyl;

[0053] Rc is represented by one of a protium atom, a deuterium atom, a tritium atom, a methyl, an ethyl, a propyl, an isopropyl, a tert-butyl, a butyl, a phenyl, a biphenyl, a naphthyl, an anthryl, a phenanthryl, a pyridyl, a pyrimidinyl, a pyrazinyl, a benzoxazolyl, a benzothiazolyl, a quinoxalinyl, a quinolinyl, an isoquinolinyl, a furyl, a thienyl, an indolyl, a pyrrolyl, a dibenzofuranyl, a dibenzothiophenyl, a 9,9-dimethylfluorenyl, a spirofluorene, a carbazolyl, an N-phenylcarbazolyl, a carbazolinyl, and an aza-phenanthrenyl;

[0054] The substituents for the substituting groups are each independently selected from one or more of a deuterium atom, a chlorine atom, a fluorine atom, a nitroso group, a nitro group, an acyl group, a carbonyl group, a carboxylic acid group, an ester group, an isocyano group, -SCN, -OCN, -SF5, a boranyl group, a sulfinyl group, a sulfonyl group, a phosphonyloxy group, -CF3, -C2F5, -OCF3, -OC2F5, SO2CH3, SO2CF3, an adamantyl group, a cyano group, a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-pentyl group, a tert-butyl group, a butyl group, a silylmethane group, a trimethylsilyl group, an isopropyldimethylsilyl group, a methoxy group, a phenyl group, a biphenyl group, a naphthyl group, an anthracenyl group, a phenanthryl group, a pyridyl group, a pyrimidinyl group, a pyrazinyl group, a benzoxazolyl group, a benzothiazolyl group, a quinoxalinyl group, a quinolinyl group, an isoquinolinyl group, a furyl group, a thienyl group, an indolyl group, a pyrrolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a 9,9-dimethylfluorenyl group, a spirofluorene group, a carbazolyl group, an N-phenylcarbazolyl group, a carbazolinyl group, an azaphenanthryl group.<0 of the

[0055] Further preferably, the structure of the general formula (1) is any one of the following structures:

[0056]

[0057]

[0058] The structure of the general formula (2) is any one of the following structures:

[0059]

[0060]

[0061]

[0062] In a preferred embodiment, the structure of the general formula (3) is any one of the following structures:

[0063]

[0064]

[0065] The structure of the general formula (4) is any one of the following structures:

[0066]

[0067]

[0068]

[0069] In a preferred embodiment, the structure of the general formula (5) is any one of the following structures;

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076]

[0077]

[0078] Preferred embodiment, the structure of the general formula (6) is any one of the following structures:

[0079]

[0080] Preferred embodiment, the structure of the general formula (7) can be any one of the following structures:

[0081]

[0082]

[0083]

[0084]

[0085] Preferred embodiment, the organic light-emitting functional layer is composed of a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport material layer, and an electron injection layer, or the organic light-emitting functional layer is composed of a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron transport material layer, and an electron injection layer; the mass ratio of the hole transport material to the P-type doping material in the hole injection layer is 99:1 - 95:5, preferably 99:1 - 97:3; the mass fraction of the doping material in the light-emitting layer ≤ 10%, preferably 2 - 5%.

[0086] An application of a blue organic electroluminescent device in a display or lighting device.

[0087] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0088] 1. The reasonable combination of the specific hole injection layer material, hole transport layer material, electron blocking layer material, and host-guest of the light-emitting layer in the present invention can reduce the device voltage, improve the luminous efficiency, and improve the device lifetime.

[0089] 2. The hole injection layer of the present invention is formed by doping a P-doped material with a specific structure into the hole transport layer material, which can form a good ohmic contact and significantly reduce the injection barrier between the electrode and the hole transport material, improve injection, and reduce the device voltage.

[0090] 3. The hole transport layer material of the present invention has appropriate HOMO energy levels and hole mobilities, and the reasonable combination form of the hole transport material and the P-doped material promotes good hole transport effects. At the same time, the combined electron blocking layer material has appropriate HOMO / LUMO energy levels and good hole mobilities, realizing high hole transport in the transport region, increasing the recombination probability of excitons in the light-emitting layer, and improving the light-emitting efficiency of the device.

[0091] 4. The host material of the present invention has good hole and electron mobilities, is doped with pyrene-based or boron-containing materials, and is fixedly combined with the light-emitting layer material in the hole transport region of the present invention, enabling high color purity of the device, reducing the device driving voltage, and improving the device efficiency and lifespan. Brief Description of the Drawings

[0092] Figure 1 is a schematic structural diagram of the organic electroluminescent device of the present invention;

[0093] Figure 1 In it, 1. Substrate 100, 2. First electrode 200, 3. Organic light-emitting functional layer 300, 4. Second electrode 400, 5. Cover layer 500.

[0094] Figure 2 is a cross-sectional view of the organic light-emitting functional layer 300 of the organic electroluminescent device of the present invention;

[0095] In the figure, 1. Hole injection layer 310, 2. Hole transport layer 320, 3. Electron blocking layer 330, 4. Light-emitting layer 340, 5. Hole blocking layer 350, 6. Electron transport layer 360, 7. Electron injection layer 370.

[0096] Figure 3-1 is the 1H NMR spectrum of the first compound BH-1 in the light-emitting layer.

[0097] Figure 3-2 is a partial enlarged view of the 1H NMR spectrum of the first compound BH-1 in the light-emitting layer.

[0098] Figure 4 is the mass spectrum of the first compound BH-1 in the light-emitting layer. Detailed Description of the Embodiments

[0099] The present invention will be further described in detail below with reference to the drawings and embodiments. However, they can be implemented in different forms and should not be construed as limited to the embodiments described herein. On the contrary, these embodiments are provided to make the present disclosure more complete and thorough.

[0100] In this text, the aryl groups, aryl groups having 6 - 30 carbon atoms, aryl groups of C 6-50 and aryl groups of C 6-30 Non - limiting examples may include phenyl, naphthyl, anthryl, phenanthryl, condensed tetraphenyl, pyrenyl, biphenyl, p - terphenyl, m - terphenyl, anthryl, group, dianthryl, perylenyl, indenyl, triphenylenyl, fluoranthenyl, fluorenyl, dimethylfluorenyl, 9,9 - diphenylfluorenyl, spirobifluorenyl, a group formed by condensation of phenyl and spirobifluorenyl, etc.

[0101] Heteroaryl groups, heteroaryl groups having 3 - 30 carbon atoms, heteroaryl groups having 5 - 50 ring - forming atoms, 5 - 30 - membered heteroaryl groups containing one or more heteroatoms. Non - limiting examples may include furyl, thienyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, oxazolyl, thiazolyl, oxadiazolyl, thiadiazolyl, pyridyl, pyrimidinyl, pyrazinyl, triazinyl, benzofuryl, benzothienyl, benzimidazolyl, indolyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, naphthyridinyl, benzoxazinyl, benzothiazinyl, acridinyl, phenazinyl, phenothiazinyl, phenoxazinyl, dibenzothiophenyl, carbazolyl, phenylsubfuran - 2 - yl, dibenzofuryl, N - phenylcarbazolyl, N - naphthylcarbazolyl, N - biphenylcarbazolyl, N - terphenylcarbazolyl, N - phenylcarbazolylphenylene, azaphenanthrenyl, etc.

[0102] C 1-10 alkyl, C 1-20 Non - limiting examples of alkyl may include adamantyl, methyl, ethyl, n - propyl, isopropyl, n - butyl, isobutyl, sec - butyl, tert - butyl, n - pentyl, isopentyl, neopentyl, tert - pentyl, 1 - methylbutyl, 2 - methylbutyl, 1 - ethylpropyl, 1,2 - dimethylpropyl, hexyl, heptyl, octyl, dodecyl, etc.

[0103] C3 - C 10 Cycloalkyl refers to a monovalent monocyclic saturated hydrocarbon group including 3 to 10 carbon atoms as ring - forming atoms. In this text, C4 - C9 cycloalkyl is preferably used, more preferably C5 - C8 cycloalkyl, and particularly preferably C5 - C7 cycloalkyl. Non - limiting examples thereof may include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, 4 - methylcyclohexyl, 4,4 - dimethylcyclohexyl, adamantyl, and cycloheptyl.

[0104] Alkoxy groups having 1 - 20 carbon atoms refer to methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, isopropoxy, etc., but are not limited thereto.

[0105] C 0-10 Non-limiting examples of silyl groups may include silicamethyl, silicethyl, silicpropyl, silicisopropyl, silicbutyl, trimethylsilyl, isopropyldimethylsilyl, and the like.

[0106] Non-limiting examples of substituents for the substituent groups may include halogen atoms, adamantyl, cyano, cyano, nitroso, nitro, acyl, carbonyl, carboxyl, ester, isocyano, -SCN, -OCN, -SF5, boranyl, sulfinyl, sulfonyl, phosphonyloxy, -CF3, -C2F5, -OCF3, -OC2F5, SO2CH3, SO2CF3, silicamethyl, trimethylsilyl, isopropyldimethylsilyl, deuterium atom, tritium atom, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, 1-methylbutyl, 2-methylbutyl, 1-ethylpropyl, 1,2-dimethylpropyl, hexyl, heptyl, octyl, dodecyl, methoxy, phenyl, naphthyl, anthryl, phenanthryl, condensed tetraphenyl, pyrenyl, biphenyl, p-terphenyl, m-terphenyl, anthryl, group, bianthenyl, perylenyl, indenyl, triphenylenyl, fluoranthenyl, fluorenyl, dimethylfluorenyl, diphenylfluorenyl, spirobifluorenyl, group condensed with phenyl and spirobifluorenyl, phenyl, naphthyl, anthryl, phenanthryl, condensed tetraphenyl, pyrenyl, biphenyl, p-terphenyl, m-terphenyl, anthryl, group, bianthenyl, perylenyl, indenyl, triphenylenyl, fluoranthenyl, fluorenyl, dimethylfluorenyl, diphenylfluorenyl, spirobifluorenyl, group condensed with phenyl and spirobifluorenyl, furyl, thienyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, oxazolyl, thiazolyl, oxadiazolyl, thiadiazolyl, pyridyl, pyrimidinyl, pyrazinyl, triazinyl, benzofuryl, benzothienyl, benzimidazolyl, indolyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, naphthyridinyl, benzoxazinyl, benzothiazinyl, acridinyl, phenazinyl, phenothiazinyl, phenoxazinyl, dibenzothiophenyl, carbazolyl, phenylsubfuryl, dibenzofuryl, N-phenylcarbazolyl, N-naphthylcarbazolyl, N-biphenylcarbazolyl, N-p-terphenylcarbazolyl, N-phenylcarbazolylphenylene, one or more of azaphenanthryl.

[0107] The halogen atom refers to a chlorine atom, a fluorine atom, or a bromine atom.

[0108] The first electrode layer 200 is formed on the substrate layer 100, and the first electrode layer 200 can be a cathode or an anode. Here, the first electrode layer 200 can be a reflective electrode, such as a reflective film formed of silver (Ag), magnesium (Mg), aluminum (Al), gold (Au), nickel (Ni), chromium (Cr), ytterbium (Yb), or an alloy thereof; and a transparent or semi-transparent electrode layer formed on the reflective film and having a high work function.

[0109] The transparent or semi-transparent electrode layer can be formed of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), aluminum zinc oxide (AZO), indium gallium oxide (IGO), indium oxide (In2O3), or tin oxide (SnO2); or can be formed of a combination of a metal and an oxide, such as ITO / Ag / ITO, IGO / Al / IGO, or AZO / Ag / AZO.

[0110] The above-mentioned first electrode layer 200 can be formed by methods such as sputtering, ion plating, vacuum evaporation, spin coating, electron beam evaporation, or chemical vapor deposition (CVD), and is preferably formed by sputtering.

[0111] The thickness of the first electrode layer 200 depends on the material used, generally in the range of 5 nm - 1 μm, preferably 10 nm - 1 μm, more preferably 10 nm - 500 nm, particularly preferably 10 nm - 300 nm, and most preferably 10 nm - 200 nm.

[0112] As Figure 2 shown, the organic light-emitting functional layer 300 can include a light-emitting layer 340 (EML), and a hole transport region can be formed between the EML and the first electrode layer 200, and an electron transport region can be formed between the EML and the second electrode layer 400. The hole transport region can include at least one of a hole injection layer 310 (HIL), a hole transport layer 320 (HTL), and an electron blocking layer 330 (EBL). The electron transport region can include at least one of a hole blocking layer 350 (HBL), an electron transport layer 360 (ETL), and an electron injection layer 370 (EIL). Therefore, the organic light-emitting functional layer 300 includes at least two combinations of a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer, and an electron injection layer.

[0113] The thickness of the organic light-emitting functional layer 300 is 50 nm - 1000 nm.

[0114] The P-type doping material is mainly used for hole injection. The P-type doping material is incorporated into the hole transport layer to form a charge transfer state with the hole transport host material, making it easier for holes to be injected into the organic material layer. In the present invention, the P-type doping material is selected from the structures of general formula (1) or general formula (2); the P-type doping material is preferably one of the following compounds:

[0115]

[0116] At least one of HIL310 and HTL320 may further include a charge generation material for improving conductivity. The charge generation material may be a p-dopant. In the present invention, the hole transport material is selected from the structures of general formula (3) or general formula (4); the hole transport material is preferably one of the following compounds:

[0117]

[0118] It is required that the triplet (T1) energy level of the material in EBL330 is higher than the T1 energy level of the host material in the light-emitting layer 340, which can play a role in blocking the energy loss of the light-emitting layer material; the HOMO energy level of the EBL330 material is between the HOMO energy level of the HTL320 material and the HOMO energy level of the host material in the light-emitting layer 340, which is beneficial to the injection of holes from the positive electrode into the light-emitting layer. At the same time, it is required that the EBL330 material has a high hole mobility, which is beneficial to hole transport and reduces the device driving voltage; the LUMO energy level of the EBL330 material is higher than the LUMO energy level of the host material in the light-emitting layer 340, playing an electron blocking role, that is, it is required that the EBL330 material has a wide bandgap (Eg). In the present invention, the electron blocking layer material is selected from the structure shown in general formula (5); the electron blocking layer material is preferably one of the following compounds;

[0119]

[0120] In the present invention, the light-emitting layer is composed of a fluorescent material. The fluorescent light-emitting layer contains a first compound (host material) and a dopant material (guest material), and is characterized in that the first compound is selected from general formula (6) and is used as the host material; the doping material is selected from general formula (7) or general formula (8).

[0121] The first compound is preferably one of the following compounds:

[0122]

[0123] The preferred doping material is selected from one of the following compounds:

[0124]

[0125]

[0126] The organic electroluminescent device described above, wherein the mass fraction of the doping material in the fluorescent light-emitting layer is ≤ 10%, preferably 2-5%;

[0127] For the materials of the hole blocking layer 350 and the electron transport layer 360 constituting the above OLED device, any material with electron transport characteristics for OLED can be selected for use. Such materials include, for example, 1,3-bis[5'-(p-tert-butylphenyl)-1,3,4-oxadiazol-2'-yl]benzene, oxadiazole derivatives such as 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole, triazole derivatives such as 3-(4'-tert-butylphenyl)-4-phenyl-5-(4''-biphenyl)-1,2,4-triazole, triazine derivatives, quinoline derivatives, quinoxaline derivatives, diphenylquinone derivatives, nitro-substituted fluorenone derivatives, thiopyran dioxide derivatives, anthraquinone dimethane derivatives, thiopyran dioxide derivatives, heterocyclic tetracarboxylic anhydrides such as naphthyl perylene, carbodiimide, fluorene derivatives, anthraquinone dimethane derivatives, anthrone derivatives, stilbenylpyrazine derivatives, silole derivatives, phenanthroline derivatives or imidazopyridine derivatives.

[0128] In addition, organometallic complexes such as bis(10-benzo[h]quinolinolato)beryllium, beryllium salt of 5-hydroxyflavone, aluminum salt of 5-hydroxyflavone, or metal complexes of 8-hydroxyquinoline or its derivatives can also be mentioned, such as tris(8-hydroxyquinolinato)aluminum (Alq), tris(5,7-dichloro-8-hydroxyquinolinato)aluminum, bis(2-methyl-8-hydroxyquinolinato)(p-phenylphenolato)aluminum (BAlq), tris(5,7-dibromo-8-hydroxyquinolinato)aluminum, tris(2-methyl-8-hydroxyquinolinato)aluminum, etc. Metal chelate compounds containing chelating agents such as plant hormones (generally 8-hydroxyquinoline) and other hydroxyquinoline metal complexes. In addition, examples of metal complexes in which the central metal of these metal complexes is replaced by beryllium, indium, magnesium, copper, calcium, tin, zinc or aluminum can also be mentioned. It is preferred to use non-metals, metal phthalocyanines or substances in which their ends are replaced by alkyl groups, sulfonic groups, etc. Among them, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and 3-phenyl-4-(1'-naphthyl)-5-phenyl-1,2,4-triazole (TAZ) are more preferably used.

[0129] In HBL350, it is required that the triplet (T1) energy level of the material is higher than the T1 energy level of the host material in the light-emitting layer 340, which can play a role in blocking the energy loss of the light-emitting layer material; the HUMO energy level of the EBL350 material is lower than the HUMO energy level of the host material in the light-emitting layer 340, playing a role in hole blocking. At the same time, it is required that the HBL350 material has a high electron mobility, which is beneficial to electron transport and reduces the device application power; the HBL350 material meeting the above conditions can be triazine derivatives, azobenzene derivatives, etc. Among them, triazine derivatives are preferred; but not limited thereto.

[0130] EIL370 can be formed by one or more of the following substances: alkali metals; alkaline earth metals; halides of alkali metals and alkaline earth metals; oxides of alkali metals and alkaline earth metals, carbonates of alkali metals and alkaline earth metals; oxalates of alkali metals and alkaline earth metals or fluoroaluminates of alkali metals and alkaline earth metals. Examples can be cited such as Li, Ca, Sr, LiF, CsF, BaO, Li2CO3, CaCO3, Li2C2O4, Cs2C2O4, CsAlF4. In some embodiments, EIL370 can include at least one metal, such as one or more of Yb, Sc, V, Y, In, Ce, Sm, Eu or Tb.

[0131] A second electrode layer 400 is formed on the organic light-emitting functional layer 300. The second electrode layer can be a cathode or an anode, and can be a transparent electrode or a semi-transparent electrode. The second electrode layer 400 can be made of a thin film with a low work function formed by lithium, calcium, lithium fluoride / calcium, lithium fluoride / aluminum, aluminum, silver, magnesium or their alloys. Further, the second electrode layer 400 can be made of an alloy including silver and at least one metal, and the at least one metal includes aluminum, platinum, ytterbium, chromium or magnesium. And, the weight ratio of Ag in the alloy can be the same as, greater than or less than the weight ratio of other metals. For example: the second electrode layer 400 can be formed by an Ag-Mg alloy, and the mass ratio of Ag and Mg can be 90:10 to 10:90. Or, the second electrode layer 400 can be formed by an alloy including at least one metal such as silver, gold, platinum, copper, nickel or tungsten and at least one metal such as ytterbium, indium, magnesium or chromium. These metal films can form transparent or semi-transparent electrodes by adjusting the film thickness. Therefore, the light generated by the organic light-emitting functional layer 300 can be emitted through the second electrode layer 400. And, the thickness of the second electrode layer 400 can be 5 - 20 nm.

[0132] A cover layer (CPL) 500 is formed on the second electrode layer 400. The material of the cover layer 500 is selected from aromatic amine derivatives, carbazole derivatives, triazine derivatives or pyridine derivatives. The thickness of the cover layer is 10 - 1000 nm, preferably 40 - 140 nm.

[0133] Preferred CPL materials can be selected from the following structures

[0134]

[0135] Reference Figure 1 , the organic electroluminescent device of the present invention includes a substrate layer 100, a first electrode layer 200, an organic light-emitting functional layer 300, a second electrode layer 400, and a cover layer 500.

[0136] On the substrate layer, a barrier layer (which can be composed of inorganic materials or / and organic materials and is used to prevent foreign substances from penetrating the substrate and the device) and a wiring layer (which can include driving TFTs, capacitors, wires, and low-temperature polysilicon LTPS) can be formed by known methods.

[0137] In a specific embodiment, the first electrode layer 200 can be a reflective electrode and the second electrode layer 400 is a transparent or semi-transparent electrode. Therefore, the light generated by the organic light-emitting functional layer 300 can be directly emitted by the second electrode layer 400, or can be reflected by the first electrode layer 200 towards the second electrode layer 400 and then emitted. The first electrode layer 200 can be prepared by, for example, evaporation or sputtering. The second electrode layer 400 can be prepared by, for example, vacuum evaporation.

[0138] The organic light-emitting functional layer 300 can include a light-emitting layer 340 (EML), and a hole transport region can be formed between the EML and the first electrode layer 200, and an electron transport region can be formed between the EML and the second electrode layer 400. The hole transport region can include at least one of a hole injection layer 310 (HIL), a hole transport layer 320 (HTL), and an electron blocking layer 330 (EBL). The electron transport region can include at least one of a hole blocking layer 350 (HBL), an electron transport layer 360 (ETL), and an electron injection layer 370 (EIL).

[0139] Exemplary embodiments have been disclosed herein. Although specific terms are used therein, these terms are used only and are interpreted only as general and descriptive meanings, and not for the purpose of limitation. In some cases, as will be obvious to those of ordinary skill in the art upon the filing of this application, unless specifically indicated, the features, characteristics, and / or elements described in connection with a particular embodiment can be used alone or in combination with the features, characteristics, and / or elements described in connection with other embodiments. Accordingly, those skilled in the art will understand that various changes can be made in form and detail without departing from the spirit and scope of the present invention.

[0140] The following examples are intended to better explain the present invention, but the scope of the present invention is not limited thereto.

[0141] Examples

[0142] I. Preparation Examples of Compounds

[0143] The raw materials involved in the synthesis examples of the present invention can all be purchased from the market or prepared by conventional preparation methods in the art;

[0144] Synthesis Example 1: Synthesis of Compound BH-1

[0145]

[0146] In a 250 mL three-necked flask, nitrogen was introduced, 0.02 mol of raw material A1, 0.045 mol of raw material B1 and 0.06 mol of K2CO3 were added, 60 mL of 1,4-dioxane and 20 mL of water were added, and then 0.0004 mol of tetrakis(triphenylphosphine)palladium was added. Stir and heat under reflux for 12 hours. Sampling and TLC analysis showed that there was no remaining raw material A1, and the reaction was complete. After natural cooling, the mixture was rotary evaporated and then dissolved in 100 mL of dichloromethane, washed with 80 mL of water, and the layers were separated. The aqueous layer was extracted with dichloromethane three times. The combined organic phases were dried over anhydrous magnesium sulfate, filtered, and the filtrate was rotary evaporated and purified by silica gel column chromatography to obtain BH-1. Elemental analysis results (molecular formula C 34 H 22 ): Theoretical values: C, 94.85; H, 5.15; Measured values: C, 94.87; H, 5.13. LC-MS: Measured value: 431.18 ([M+H] + ); Exact mass: 430.17. The 1H NMR spectrum and mass spectrum of BH-1 are shown in Figure 3-1 、 3-2 、4 respectively.

[0147] Synthesis Example 2: Synthesis of Compound BH-2

[0148]

[0149] In a 250 mL three-necked flask, nitrogen was introduced, 0.01 mol of BH-1 and 0.005 mol of AlCl3 were added, 100 mL of C6D6 was added, and the mixture was stirred for 2 hours. After the reaction was completed, 15 mL of D2O was added and stirred for 30 minutes, and then trimethylamine (1.5 mL) was added dropwise. The reaction solution was transferred to a separatory funnel and extracted with water and toluene. The extract was dried over anhydrous magnesium sulfate and then recrystallized from ethyl acetate to obtain BH-2. Elemental analysis results (molecular formula C 34 D 22 ): Theoretical values: C, 90.21; H, 9.79; Measured values: C, 90.24; H, 9.76. LC-MS: Measured value: 453.11 ([M+H] + ); Exact mass: 452.31.

[0150] Synthesis Example 3: Synthesis of Compound BH-6:

[0151]

[0152] In a 250 mL three-necked flask, nitrogen was introduced, 0.02 mol of raw material A1, 0.045 mol of raw material B2 and 0.06 mol of K2CO3 were added, 60 mL of 1,4-dioxane and 20 mL of water were added, and then 0.0004 mol of tetrakis(triphenylphosphine)palladium was added. Stir and heat under reflux for 16 hours. Sampling and TLC analysis showed that there was no remaining raw material A1, and the reaction was complete. After natural cooling, the mixture was rotary evaporated and then dissolved in 100 mL of dichloromethane, washed with 80 mL of water, and separated. The aqueous layer was extracted with dichloromethane three times. The combined organic phases were dried over anhydrous magnesium sulfate, filtered, the filtrate was rotary evaporated, and purified by silica gel column chromatography to obtain BH-6. Elemental analysis results (molecular formula C 34 H8D 14 ): Theoretical values: C, 91.84; H, 8.16; Measured values: C, 91.86; H, 8.14. LC-MS: Measured value: 445.08 ([M+H] + ); Exact mass: 444.26.

[0153] Synthesis Example 4: Synthesis of Compound BH-7:

[0154]

[0155] In a 250 mL three-necked flask, nitrogen was introduced, 0.02 mol of raw material A1, 0.02 mol of raw material B1 and 0.06 mol of K2CO3 were added, 60 mL of 1,4-dioxane and 20 mL of water were added, and then 0.0004 mol of tetrakis(triphenylphosphine)palladium was added. Stir and heat under reflux for 8 hours. Sampling and TLC analysis showed that there was no remaining raw material A1, and the reaction was complete. After natural cooling, the mixture was rotary evaporated and then dissolved in 100 mL of dichloromethane, washed with 80 mL of water, and separated. The aqueous layer was extracted with dichloromethane three times. The combined organic phases were dried over anhydrous magnesium sulfate, filtered, the filtrate was rotary evaporated, and purified by silica gel column chromatography to obtain intermediate C1. Elemental analysis results (molecular formula C 24 H 15 Br): Theoretical values: C, 75.21; H, 3.94; Br, 20.85; Measured values: C, 75.23; H, 3.91; Br, 20.87. LC-MS: Measured value: 383.16 ([M+H] + ); Exact mass: 382.04.

[0156] In a 250 mL three-necked flask, nitrogen was introduced, 0.01 mol of intermediate C1, 0.012 mol of raw material B2, and 0.03 mol of K2CO3 were added. 60 mL of 1,4-dioxane and 20 mL of water were added, and then 0.0002 mol of tetrakis(triphenylphosphine)palladium was added. The mixture was stirred and heated under reflux for 14 hours. A sample was taken for TLC, and it was found that no intermediate C1 remained, indicating that the reaction was complete. It was naturally cooled, and after rotary evaporation, it was dissolved in 100 mL of dichloromethane, washed with 80 mL of water, and the layers were separated. The aqueous layer was extracted three times with dichloromethane. The combined organic phases were dried over anhydrous magnesium sulfate, filtered, and the filtrate was rotary evaporated and purified by silica gel column chromatography to obtain BH-7. Elemental analysis results (molecular formula C 34 H 15 D7): Theoretical values: C, 93.32; H, 6.68; Measured values: C, 93.35; H, 6.65. LC-MS: Measured value: 438.19 ([M+H] + ); Exact mass: 437.22.

[0157] The application effects of the compounds synthesized by the present invention as luminescent layer materials in devices are described in detail below through Device Examples 1-48 and Device Comparative Examples 1-12. Compared with Device Example 1, Device Examples 2-48 and Device Comparative Examples 1-12 have exactly the same device manufacturing process, and the same substrate materials and electrode materials are used. The film thicknesses of the electrode materials are also consistent. The differences are that the materials of the hole injection layer, hole transport layer, electron blocking layer, luminescent layer, and hole blocking layer in the device are changed. The device stack structure is shown in Table 1, and the performance test results of each device are shown in Table 2.

[0158] Device Example 1

[0159] Substrate layer 100 / First electrode layer 200 (ITO (15 nm) / Ag (150 nm) / ITO (15 nm)) / Hole injection layer 310 (HT-1:P-1 = 97:3 mass ratio, thickness 10 nm) / Hole transport layer 320 (HT-1, thickness 140 nm) / Electron blocking layer 330 (EB-1, thickness 5 nm) / Luminescent layer 340 (BH-1:BD-1 = 97:3 mass ratio, thickness 20 nm) / Hole blocking layer 350 (HB-1, thickness 5 nm) / Electron transport layer 360 (ET-1:Liq = 1:1 mass ratio, thickness 30 nm) / Electron injection layer 370 (Yb, thickness 1 nm) / Second electrode layer 400 (Mg:Ag = 1:9 mass ratio, thickness 13 nm) / Cover layer 500 (CPL-4, thickness 65 nm).

[0160] The specific preparation process is as follows:

[0161] As Figure 1 and Figure 2As shown, the substrate layer 100 is a PI film. The ITO (15 nm) / Ag (150 nm) / ITO (15 nm) used as the first electrode 200 is washed, that is, alkali washing, pure water washing, and drying are carried out in sequence, and then ultraviolet-ozone washing is carried out to remove organic residues on the surface of the anode layer. On the first electrode 200 after the above washing, the organic light-emitting functional layer 300 is deposited by a vacuum evaporation device. First, HT-1 and P-1 with a film thickness of 10 nm are deposited as the hole injection layer 310, and the mass ratio of HT-1 and P-1 is 97:3. Then, HT-1 with a thickness of 140 nm is deposited as the hole transport layer 320. Subsequently, EB-1 with a thickness of 5 nm is deposited as the electron blocking layer 330. After the deposition of the above electron blocking layer material, the light-emitting layer 340 of the OLED light-emitting device is fabricated. Its structure includes BH-1 used in the light-emitting layer 340 as the first compound (host material) of the light-emitting layer, BD-1 as the doping material, and the mass ratio of BH-1 and BD-1 is 97:3, and the film thickness of the light-emitting layer is 20 nm. After the above light-emitting layer 340, 5 nm of HB-1 is continuously deposited and used as the hole blocking layer 350. On the hole blocking layer 350, an ET-1 and Liq mixed film is continuously deposited by vacuum evaporation as the electron transport layer 360, and the mass ratio of ET-1 and Liq is 1:1, and the film thickness is 30 nm. On the electron transport layer 360, a Yb layer with a film thickness of 1 nm is fabricated by a vacuum evaporation device, and this layer is the electron injection layer 370. On the electron injection layer 370, a Mg:Ag electrode layer with a film thickness of 13 nm is fabricated by a vacuum evaporation device, and the mass ratio of Mg and Ag is 1:9, and this layer is used as the second electrode 400. On the second electrode 400, 65 nm of CPL-4 is deposited by vacuum evaporation and used as the cover layer 500.

[0162] After completing the fabrication of the electroluminescent device according to the above steps, the efficiency data and light decay lifetime of the device are measured, and the results are shown in Table 2. The molecular structural formulas of the related materials are as follows:

[0163]

[0164] Table 1

[0165]

[0166]

[0167]

[0168] The device was tested for its driving voltage, current efficiency, CIEx, CIEy and LT95 lifetime. The voltage, current efficiency, CIEx and CIEy were tested using an IVL (current-voltage-luminance) test system (Suzhou Fushida Scientific Instruments Co., Ltd.), and the current density during the test was 10 mA / cm 2 . LT95 refers to the time when the device brightness decays to 95% of the initial brightness, and the current density during the test was 50 mA / cm 2 ; The lifetime test system was the EAS-62C type OLED device lifetime tester of System Technology Research Co., Ltd. of Japan. The efficiency and lifetime data of each device example and device comparative example are shown in Table 2.

[0169] Table 2

[0170]

[0171]

[0172]

[0173] It can be seen from the results in Table 2 that under the limitation of the hole injection layer material, hole transport layer material and electron blocking layer material in the present invention, compared with the host material of the comparative example, the driving voltage of the device prepared by the combination of the blue light host material and the blue light doping material in the present invention is significantly reduced, and both the luminous efficiency and the lifetime are significantly improved; under the limitation of the hole injection layer material, hole transport layer material and electron blocking layer material in the present invention, and for the device prepared by the combination of the host material and the blue light doping material in the present invention, compared with the case without the hole blocking layer material, the voltage of the device with the hole blocking layer material is reduced, and the luminous efficiency and LT95 lifetime are improved to a certain extent. Under the limitation of the hole transport layer material and the electron blocking layer material in the present invention, and for the device prepared by the combination of the host material and the blue light doping material in the present invention, compared with the hole injection layer material containing HAT-CN, the voltage of the device with the P-doped material doped into the hole transport material of the present invention as the hole injection layer material is significantly reduced, and the LT95 lifetime of the device is significantly improved. With the electron blocking layer material compared with without the electron blocking layer material, the driving voltage of the device prepared by the combination of the blue light host material and the blue light doping material in the present invention is significantly reduced, and both the luminous efficiency and the lifetime are significantly improved; mainly due to the good hole injection and transport in the hole transport region, combined with the luminescent layer doping material with a narrow Stokes shift and the luminescent layer with the compound of the general formula (6) in the present invention as the host material, which promotes the blue light device to have good hole mobility and electron mobility, and at the same time has excellent TTF effect, improves the utilization rate of triplet excitons, thereby enhancing the luminous efficiency and lifetime of the device; at the same time, it has a faster carrier migration rate, which can effectively reduce the device voltage.

Claims

1. A blue organic electroluminescent device, which comprises: a substrate layer; a first electrode, which is on the substrate layer; an organic light-emitting functional layer, which is on the first electrode; a second electrode, which is on the organic light-emitting functional layer; and a covering layer, which is on the second electrode; characterized in that the organic light-emitting functional layer sequentially includes a hole injection layer, a hole transport layer, an electron blocking layer and a light-emitting layer, the hole injection layer is adjacent to the first electrode, the hole transport layer is located between the hole injection layer and the electron blocking layer, and the electron blocking layer is located between the hole transport layer and the light-emitting layer, wherein the hole injection layer is jointly formed by a hole transport material represented by general formula (3) or general formula (4) and a P-type doping material, and the P-type doping material is selected from a compound represented by general formula (1) or general formula (2); the hole transport layer contains a hole transport material represented by general formula (3) or general formula (4); the electron blocking layer contains a compound represented by general formula (5); the light-emitting layer contains a first compound and a doping material, the structure of the first compound is as shown in general formula (6), the doping material is selected from one of the compounds represented by general formula (7) or general formula (8), and the peak value of the intrinsic emission spectrum of the doping material is between 450 and 470 nm; In general formula (1), each occurrence of R is independently selected from an aryl group or a heteroaryl group, and the aryl group or heteroaryl group is substituted or unsubstituted by an electron acceptor group; In general formula (2), X and Y are each independently selected from CR”R”’, NR’, O, S or Se; Z1 and Z2 are each independently selected from O, S or Se; In general formula (2), R1, R’, R”, and R”’ are each independently the same or different and are selected from hydrogen, deuterium, halogen, nitroso, nitro, acyl, carbonyl, carboxyl, ester, cyano, isocyano, -SCN, -OCN, -SF5, boranyl, sulfinyl, sulfonyl, phosphonyloxy, substituted or unsubstituted C 1-20 alkyl, substituted or unsubstituted C 3-20 cycloalkyl, substituted or unsubstituted heteroalkyl having 1-20 carbon atoms, substituted or unsubstituted aralkyl having 7-30 carbon atoms, substituted or unsubstituted alkoxy having 1-20 carbon atoms, substituted or unsubstituted aryloxy having 6-30 carbon atoms, substituted or unsubstituted alkenyl having 2-20 carbon atoms, substituted or unsubstituted alkynyl having 2-20 carbon atoms, substituted or unsubstituted aryl having 6-30 carbon atoms, substituted or unsubstituted heteroaryl having 3-30 carbon atoms, substituted or unsubstituted alkylsilyl having 3-20 carbon atoms, substituted or unsubstituted arylsilyl having 6-20 carbon atoms, one or more thereof; provided that at least one of R1, R’, R”, and R”’ is a group having at least one electron-withdrawing group; adjacent substituents may optionally be joined to form a ring; In general formula (3), R2, R3, R4, and R5 each independently represent one of a hydrogen atom, a protium atom, a deuterium atom, a tritium atom, a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, and a phenyl group; R2, R3, R4, and R5 may be the same as or different from each other; L represents a single bond, a phenylene group, a naphthylene group, or a biphenylene group; Ar1 and Ar2 each independently represent one of a substituted or unsubstituted C 6-50 aryl group, a substituted or unsubstituted heteroaryl group having 5 to 50 ring-forming atoms; Ar1 and Ar2 may be the same as or different from each other; In general formula (4), A represents any one of a single bond, and the like; wherein q is represented as 0 or 1; Ar3, Ar4, Ar5, Ar6, Ar7, and Ar8 are each independently represented as one of a substituted or unsubstituted aryl group having C 6-50 with a ring-forming atom number of 5 to 50, or a substituted or unsubstituted heteroaryl group; Ar3 to Ar8 may be the same as or different from each other; The dotted line indicates that the two groups are bonded in a single bond form or not connected; In general formula (5), g is 0, 1 or 2; R6 and R7 are each independently represented as a hydrogen atom, a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted carbazolyl group or a substituted or unsubstituted dibenzofuranyl group; R8 and R9 are each independently represented as a hydrogen atom, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a benzofuranyl group or a dibenzofuranyl group, and the connection modes of R8 and R9 with general formula (5) are two connection modes of annelation or single bond substitution; L1 and L2 are each independently represented as a single bond, a phenylene group, a naphthylene group, a biphenylene group or a terphenyl group; L3 is represented as Ar9 and Ar 10 are each independently represented as one of a substituted or unsubstituted aryl group having C 6-50 and a substituted or unsubstituted heteroaryl group having 5 to 50 ring-forming atoms. In general formula (6), a and e each independently represent 0, 1, 2, or 3; b, c, d, and f each independently represent 0, 1, 2, 3, or 4; R 15 ~R 20 each independently represents a hydrogen atom or a deuterium atom; In general formula (7), R 11 , R 12 each independently represents a hydrogen atom, a protium atom, a deuterium atom, a tritium atom, a cyano group, a substituted or unsubstituted C 1-20 alkyl group, a substituted or unsubstituted C 3-20 cycloalkyl group, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group of C 6-50 , or a substituted or unsubstituted heteroaryl group having 5 to 50 ring-forming atoms; Ar 11 、 Ar 12 each occurrence of the same or different aryl groups representing substituted or unsubstituted C 6-50 or one of the substituted or unsubstituted heteroaryl groups having 5 to 50 ring-forming atoms; In general formula (8), m, n, and p each independently represent 0, 1, 2, or 3; A1, A2, and A3 each independently represent one of a substituted or unsubstituted aryl group of C 6-50 , a substituted or unsubstituted heteroaryl group having 5 to 50 ring-forming atoms; Ra to Rb each independently represent a substituted or unsubstituted alkyl group of C 1-20 , a substituted or unsubstituted cycloalkyl group of C 3-20 , a substituted or unsubstituted aryl group of C 6-50 , or a substituted or unsubstituted heteroaryl group having 5 to 50 ring-forming atoms; Rc to Re each independently represent a hydrogen atom, a protium atom, a deuterium atom, a tritium atom, a cyano group, a substituted or unsubstituted C 1-20 alkyl group, a substituted or unsubstituted C 3-20 cycloalkyl group, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted C 6-50 aryl group, or a substituted or unsubstituted heteroaryl group having 5 to 50 ring-forming atoms; Between two adjacent Rc, two Rd or two Re, between Ra and Rc, Ra and Rd, Rb and Rc, Rb and Re, Rd and Re are bonded to form a substituted or unsubstituted ring structure or are not bonded to each other; In General Formulas (1) - (8), the substituents for the substituting groups are each independently selected from a deuterium atom, a halogen atom, a nitroso group, a nitro group, an acyl group, a carbonyl group, a carboxylic acid group, an ester group, an isocyano group, -SCN, -OCN, -SF5, a boranyl group, a sulfinyl group, a sulfonyl group, a phosphonyloxy group, C 1-10 alkoxy group, an adamantyl group, a cyano group, C 1-10 alkyl group, C 0-10 silyl group, C 3-20 cycloalkyl group, C 6-30 aryl group, or a 5-30 membered heteroaryl group containing one or more heteroatoms, where the heteroatoms are each independently selected from one or more of an oxygen atom, a sulfur atom, and a nitrogen atom.

2. The blue organic electroluminescent device according to claim 1, wherein The structure of the compound represented by general formula (5) is as shown in any one of general formula (5-1) to general formula (5-3): In General Formulas (5-1) to (5-3), Ar9, Ar 10 , L1, L2, R6 to R9, and g are as defined in claim 1; The structure of the doping material in the light-emitting layer is as shown in any one of general formula (7-1) or general formula (8-1): In general formula (7-1), Ar 11 , Ar 12 each occurrence, independently of the others, represents a substituted or unsubstituted aryl group having from 6 to 50 carbon atoms 6-50 or a substituted or unsubstituted heteroaryl group having from 5 to 50 ring atoms; In general formula (8-1), Z1 to Z 11 each independently represents CRc or a nitrogen atom; Ra and Rb each independently represent a substituted or unsubstituted C 1-20 alkyl group, a substituted or unsubstituted C 3-20 cycloalkyl group, a substituted or unsubstituted C 6-50 aryl group, or one of a substituted or unsubstituted heteroaryl group having 5 to 50 ring-forming atoms; Rc represents a protium atom, a deuterium atom, a tritium atom, a cyano group, a substituted or unsubstituted C 1-20 alkyl group, a substituted or unsubstituted C 3-20 cycloalkyl group, an amino group, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted C 6-50 aryl group, or a substituted or unsubstituted heteroaryl group having 5 to 50 ring-forming atoms; between adjacent Ra, Rb, Rc, and between two adjacent Rc, they are bonded to each other to form a substituted or unsubstituted ring structure or are not bonded to each other; The substituents for the substituting groups are each independently selected from a deuterium atom, a halogen atom, a nitroso group, a nitro group, an acyl group, a carbonyl group, a carboxylic acid group, an ester group, an isocyano group, -SCN, -OCN, -SF5, a boranyl group, a sulfinyl group, a sulfonyl group, a phosphinyloxy group, C 1-10 alkoxy group, an adamantyl group, a cyano group, C 1-10 alkyl group, C 0-10 silyl group, C 3-20 cycloalkyl group, C 6-30 aryl group, or a 5- to 30-membered heteroaryl group containing one or more heteroatoms, wherein the heteroatoms are each independently selected from one or more of an oxygen atom, a sulfur atom, and a nitrogen atom.

3. The blue organic electroluminescent device according to claim 1, wherein Said Ar1, Ar2, Ar3, Ar4, Ar5, Ar6, Ar7, Ar8, Ar9, Ar 10 , Ar 11 , Ar 12 are each independently represented by one of a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted anthryl group, a substituted or unsubstituted phenanthryl group, a substituted or unsubstituted pyridyl group, a substituted or unsubstituted pyrimidinyl group, a substituted or unsubstituted pyrazinyl group, a substituted or unsubstituted benzoxazolyl group, a substituted or unsubstituted benzothiazolyl group, a substituted or unsubstituted quinoxalinyl group, a substituted or unsubstituted quinolinyl group, a substituted or unsubstituted isoquinolinyl group, a substituted or unsubstituted furyl group, a substituted or unsubstituted thienyl group, a substituted or unsubstituted indolyl group, a substituted or unsubstituted pyrrolyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothiophenyl group, a substituted or unsubstituted 9,9-dimethylfluorenyl group, a substituted or unsubstituted spirofluorene group, a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted N-phenylcarbazolyl group, a substituted or unsubstituted carbazolinyl group, a substituted or unsubstituted azaphenanthryl group; Each of Ra and Rb independently represents one of methyl, ethyl, propyl, isopropyl, tert-butyl, butyl, phenyl, biphenyl, naphthyl, anthracenyl, phenanthryl, pyridyl, pyrimidinyl, pyrazinyl, benzoxazolyl, benzothiazolyl, quinoxalinyl, quinolinyl, isoquinolinyl, furyl, thienyl, indolyl, pyrrolyl, dibenzofuranyl, dibenzothiophenyl, 9,9-dimethylfluorenyl, spirofluorene, carbazolyl, N-phenylcarbazolyl, carbazolinyl or azaphenanthryl; Rc represents one of a protium atom, a deuterium atom, a tritium atom, methyl, ethyl, propyl, isopropyl, tert-butyl, butyl, phenyl, biphenyl, naphthyl, anthracenyl, phenanthryl, pyridyl, pyrimidinyl, pyrazinyl, benzoxazolyl, benzothiazolyl, quinoxalinyl, quinolinyl, isoquinolinyl, furyl, thienyl, indolyl, pyrrolyl, dibenzofuranyl, dibenzothiophenyl, 9,9-dimethylfluorenyl, spirofluorene, carbazolyl, N-phenylcarbazolyl, carbazolinyl or azaphenanthryl; The substituents for the substitution groups are independently selected from one or more of a deuterium atom, a chlorine atom, a fluorine atom, a nitroso group, a nitro group, an acyl group, a carbonyl group, a carboxylic acid group, an ester group, an isocyano group, -SCN, -OCN, -SF5, a boranyl group, a sulfinyl group, a sulfonyl group, a phosphonyloxy group, -CF3, -C2F5, -OCF3, -OC2F5, SO2CH3, SO2CF3, an adamantyl group, a cyano group, methyl, ethyl, propyl, isopropyl, tert-pentyl, tert-butyl, butyl, a silylmethane group, a trimethylsilyl group, an isopropyldimethylsilyl group, a methoxy group, phenyl, biphenyl, naphthyl, anthracenyl, phenanthryl, pyridyl, pyrimidinyl, pyrazinyl, benzoxazolyl, benzothiazolyl, quinoxalinyl, quinolinyl, isoquinolinyl, furyl, thienyl, indolyl, pyrrolyl, dibenzofuranyl, dibenzothiophenyl, 9,9-dimethylfluorenyl, spirofluorene, carbazolyl, N-phenylcarbazolyl, carbazolinyl, azaphenanthryl.

4. The blue organic electroluminescent device according to claim 1, wherein, The structure of the general formula (1) is any one of the following structures: The structure of the general formula (2) is any one of the following structures:

5. The blue organic electroluminescent device according to claim 1, wherein The structure of the general formula (3) is any one of the following structures: The structure of the general formula (4) is any one of the following structures:

6. The blue organic electroluminescent device according to claim 1, wherein The structure of the general formula (5) is any one of the following structures:

7. The blue organic electroluminescent device according to claim 1, wherein The structure of the general formula (6) is any one of the following structures:

8. The blue organic electroluminescent device according to claim 1, wherein The structure of the general formula (7) is any one of the following structures:

9. The blue organic electroluminescent device according to claim 1, wherein, The organic light-emitting functional layer is composed of a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport material layer and an electron injection layer, or the organic light-emitting functional layer is composed of a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron transport material layer and an electron injection layer; the mass ratio of the hole transport material to the P-type doping material in the hole injection layer is 99:1 - 95:5; The mass fraction of the doping material in the light-emitting layer ≤ 10%.

10. The blue organic electroluminescent device according to claim 9, wherein, The mass ratio of the hole transport material to the P-type doping material in the hole injection layer is 99:1 - 97:

3.

11. The blue organic electroluminescent device according to claim 9, wherein The mass fraction of the doping material in the light-emitting layer is 2 - 5%.

12. Application of the blue organic electroluminescent device according to claim 1, characterized in that, For display or lighting devices.

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