CN111710787B

CN111710787B - OLED device, display device and lighting device

Info

Publication number: CN111710787B
Application number: CN202010578983.2A
Authority: CN
Inventors: 焦志强; 张大成
Original assignee: BOE Technology Group Co Ltd
Current assignee: BOE Technology Group Co Ltd
Priority date: 2020-06-23
Filing date: 2020-06-23
Publication date: 2023-03-28
Anticipated expiration: 2040-06-23
Also published as: CN111710787A

Abstract

The present invention provides an OLED device, a display apparatus and a lighting apparatus, the OLED device including: an anode and a cathode disposed opposite to each other; the organic functional layer is arranged between the cathode and the anode and comprises a phosphorescent light emitting layer, an interval connecting layer and a fluorescent light emitting layer which are sequentially stacked; a phosphorescent luminance enhancement layer disposed between the phosphorescent light emitting layer and the fluorescent light emitting layer. In the OLED device, the phosphorescence brightness improving layer can delay the diffusion of triplet excitons in the phosphorescence emitting layer to the fluorescence emitting layer, or can utilize the diffused triplet excitons for secondary light emission, thereby improving the light emitting efficiency and prolonging the service life of the OLED device.

Description

OLED device, display device and lighting device

Technical Field

The invention relates to the technical field of OLED, in particular to an OLED device, a display device and a lighting device.

Background

Since Organic Light Emitting Diode (OLED) devices have a series of excellent characteristics, they have become one of the key development directions of new generation flat panel display devices and illumination devices, and receive more and more attention. Although the OLED device manufacturing technology is mature at present, the performance of the OLED device is still a key issue that limits the OLED device to large-scale application and competitiveness.

Factors affecting the luminous efficiency of an OLED device are (1) the luminous efficiency of the luminescent material itself; (2) the utilization of excitons in OLED devices is not sufficiently high; (3) The existence of the quenching center in the OLED device causes an increase in the ratio of non-emission of excitons and the like. The factors influencing the service life of the OLED device mainly include: (1) thermal decay of organic material; (2) photo/electrochemical decay of organic material; (3) The interface formed between the two materials in the OLED device is unstable; (4) corrosion of the metal cathode; (5) The triplet excitons diffuse into the fluorescent light-emitting layer, transition to the ground state through the triplet level (T1) of fluorescence, resulting in quenching of the phosphorescence energy, which eventually manifests as a rapid decay in the lifetime of the device.

Therefore, how to make the OLED light-emitting material exert its maximum performance in the device and extend the service life of the OLED device still needs to be further developed.

Disclosure of Invention

The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. To this end, it is an object of the present invention to provide an OLED device with high luminous efficiency and long lifetime.

In one aspect of the invention, the invention provides an OLED device. According to an embodiment of the invention, the OLED device comprises: an anode and a cathode disposed opposite to each other; the organic functional layer is arranged between the cathode and the anode and comprises a phosphorescent light emitting layer, an interval connecting layer and a fluorescent light emitting layer which are sequentially stacked; a phosphorescent luminance enhancement layer disposed between the phosphorescent light emitting layer and the fluorescent light emitting layer. In the OLED device, the phosphorescence brightness improving layer can delay the diffusion of triplet excitons in the phosphorescence emitting layer to the fluorescence emitting layer, and simultaneously can utilize the diffused triplet excitons so as to improve the light emitting efficiency and prolong the service life of the OLED device.

According to an embodiment of the present invention, the phosphorescent luminance enhancement layer includes at least one of a lifetime improvement layer and an exciton buffer layer, wherein the lifetime improvement layer is disposed between the fluorescent light emitting layer and the interval connection layer or between the phosphorescent light emitting layer and the interval connection layer; the exciton buffer layer is disposed between the phosphorescent light emitting layer and the spacer connection layer.

According to an embodiment of the invention, the OLED device is a white OLED device and at least one of the following conditions is fulfilled: the fluorescent light-emitting layer is blue in light-emitting color, and the phosphorescent light-emitting layer is of a single-layer structure and is yellow in light-emitting color; the light-emitting color of the fluorescent light-emitting layer is blue, the phosphorescent light-emitting layer comprises a first phosphorescent light-emitting layer and a second phosphorescent light-emitting layer which are arranged in a stacked mode, the light-emitting color of the first phosphorescent light-emitting layer is red, and the light-emitting color of the second phosphorescent light-emitting layer is green.

According to an embodiment of the present invention, the materials of the lifetime improvement layer include a first phosphorescent host material, a thermally activated delayed fluorescence material, and a first color fluorescent guest material; the material of the exciton buffer layer includes a second phosphorescent host material.

According to an embodiment of the present invention, the lifetime improvement layer satisfies at least one of the following conditions: based on the total mass of the life improving layer, the mass percentage content of the thermal activation delayed fluorescence material is 10-35% or 25-30%; based on the total mass of the service life improving layer, the mass percentage content of the first color fluorescent guest material is 0.1-3%; the triplet energy level of the first phosphorescent host material is greater than 2.5eV; the difference between the triplet state energy level of the thermal activation delayed fluorescence material and the triplet state energy level of the host material in the fluorescence light-emitting layer is greater than or equal to 0.3eV; the thickness of the lifetime-improving layer is 0.01 to 10nm,2 to 5nm, or 0.5 to 1nm.

According to an embodiment of the present invention, any one of the following conditions is satisfied at the lifetime improvement layer: when the phosphorescent light-emitting layer is of a single-layer structure with yellow light-emitting color, the absolute value of the difference value between the light-emitting wavelength of the first-color fluorescent guest material and the light-emitting wavelength of the phosphorescent light-emitting layer is less than or equal to 10nm, and the light-emitting wavelength of the first-color fluorescent guest material is 540-580 nm; the absolute value of the difference between the light-emitting wavelength of the first-color fluorescent guest material and the light-emitting wavelength of the phosphorescent light-emitting layer is greater than or equal to 30nm, and the light-emitting wavelength of the first-color fluorescent guest material is 510-550 nm or 570-640 nm; when the phosphorescent light-emitting layer comprises a first phosphorescent light-emitting layer with red light-emitting color and a second phosphorescent light-emitting layer with green light-emitting color, the light-emitting wavelength of the first color fluorescent guest material is 500-640 nm.

According to an embodiment of the present invention, the exciton buffer layer includes a first exciton buffer layer and a second exciton buffer layer, a material of the first exciton buffer layer includes the second phosphorescent host material, and a material of the second exciton buffer layer includes an alkali metal compound including at least one of lithium fluoride, sodium chloride, potassium chloride, and sodium fluoride.

In another aspect of the invention, a display device is provided. According to an embodiment of the invention, the display device comprises the OLED device as described above. The display device has high luminous efficiency and long service life.

In yet another aspect of the present invention, the present invention provides a lighting device. According to an embodiment of the invention, the lighting device comprises the OLED device as described above. The lighting device has high luminous efficiency and long service life.

Drawings

Fig. 1 is a schematic cross-sectional view of an OLED device according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of an OLED device according to another embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of an OLED device according to another embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view of an OLED device according to another embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view of an OLED device according to another embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view of an OLED device according to another embodiment of the present invention.

FIG. 7 is a schematic cross-sectional view of an OLED device according to another embodiment of the present invention.

FIG. 8 is a schematic cross-sectional view of an OLED device according to another embodiment of the present invention.

FIG. 9 is a schematic cross-sectional view of an OLED device according to another embodiment of the present invention.

FIG. 10 is a schematic cross-sectional view of an OLED device according to example 1 of the present invention.

FIG. 11 is a schematic cross-sectional view of an OLED device according to example 2 of the present invention.

FIG. 12 is a schematic cross-sectional view of an OLED device according to example 3 of the present invention.

FIG. 13 is a schematic cross-sectional view of an OLED device according to embodiment 4 of the present invention.

FIG. 14 is a schematic sectional view showing an OLED device of example 5 of the present invention.

FIG. 15 is a schematic sectional view showing an OLED device of example 6 of the present invention.

FIG. 16 is a schematic cross-sectional view of an OLED device according to example 7 of this invention.

FIG. 17 is a schematic cross-sectional view of an OLED device according to example 8 of this invention.

FIG. 18 is a schematic cross-sectional view of an OLED device according to example 9 of this invention.

FIG. 19 is a schematic cross-sectional view of an OLED device of comparative example 1 of the present invention.

Fig. 20 is a graph of spectra of the WOLED devices of example 1 of the present invention and comparative example 1.

Fig. 21 device efficiency plots for the WOLED devices of example 1 of the invention and comparative example 1.

Fig. 22 device lifetime graphs of the WOLED devices of inventive example 1 and comparative example 1.

Detailed Description

The following describes embodiments of the present invention in detail. The following examples are illustrative only and are not to be construed as limiting the invention. The examples, where specific techniques or conditions are not indicated, are to be construed according to the techniques or conditions described in the literature in the art or according to the product specifications.

In one aspect of the invention, the invention provides an OLED device. According to an embodiment of the present invention, referring to fig. 1 and 2, the OLED device includes: an anode 10 and a cathode 20 disposed opposite to each other; an organic functional layer disposed between the cathode 20 and the anode 10, and including a phosphorescent light emitting layer 31, a spacer connecting layer 32, and a fluorescent light emitting layer 33, which are sequentially stacked; a phosphorescent luminance enhancement layer 40, the phosphorescent luminance enhancement layer 40 being disposed between the phosphorescent light emitting layer 31 and the fluorescent light emitting layer 33. In the OLED device, the phosphorescence brightness improving layer can delay the diffusion of triplet excitons in the phosphorescence light emitting layer to the fluorescence light emitting layer, and can utilize the diffused triplet excitons so as to improve the light emitting efficiency and prolong the service life of the OLED device.

It should be noted that the position of the phosphorescent light-emitting layer and the fluorescent light-emitting layer in the OLED device is not particularly limited, and the positions of the phosphorescent light-emitting layer and the fluorescent light-emitting layer may be interchanged, for example, referring to fig. 1 and 2, the phosphorescent light-emitting layer 31 is disposed near the anode 10, and the fluorescent light-emitting layer 33 is disposed near the cathode 20 in some embodiments. In yet other embodiments, the phosphorescent light emitting layer may be disposed adjacent to the cathode and the fluorescent light emitting layer may be disposed adjacent to the anode. The phosphorescent light emitting layer is disposed near the anode, and the fluorescent light emitting layer is disposed near the cathode for the purpose of illustration, but the present invention is not limited thereto.

According to an embodiment of the present invention, referring to fig. 3 to 5, the phosphorescent luminance improving layer 40 includes at least one of a lifetime improving layer 41 and an exciton buffer layer 42, wherein the lifetime improving layer 41 is disposed between the fluorescent light emitting layer 33 and the interval connecting layer 32 (refer to fig. 3) or between the phosphorescent light emitting layer 31 and the interval connecting layer 32 (refer to fig. 4); the exciton buffer layer 42 is disposed between the phosphorescent light emitting layer 31 and the spacer connection layer 32 (see fig. 5). Specifically, the introduction of the life-span improvement layer can effectively utilize the unutilized triplet excitons which are diffused to the fluorescent light-emitting layer and are about to be quenched to emit fluorescent light with the same wavelength, effectively control the quenching effect of the triplet excitons in the fluorescent light-emitting layer, and simultaneously supplement the attenuation of the phosphorescence after the OLED device is lightened, thereby realizing the effective improvement of the life span of the OLED device, improving the reliability of the full-color OLED device and not increasing the investment cost of evaporation equipment; and the diffusion of triplet excitons can be delayed by introducing the exciton buffer layer, so that the utilization efficiency of the triplet excitons is greatly improved.

It is understood that the OLED device may include only the lifetime improvement layer (see fig. 3 and 4), only the exciton buffer layer (see fig. 5), or both the lifetime improvement layer and the exciton buffer layer (see fig. 6 and 7). The method can be flexibly selected according to the use requirement and the actual production condition.

According to the embodiment of the present invention, in the OLED device, the light emitting colors of the phosphorescent light emitting layer and the fluorescent light emitting layer are not particularly limited, and may be flexibly selected according to the use requirement, for example, if the OLED device is required to emit red light, the light emitted by the phosphorescent light emitting layer and the fluorescent light emitting layer is mixed to be red, if the OLED device is required to emit white light, the light emitted by the phosphorescent light emitting layer and the fluorescent light emitting layer is mixed to be white, and the other colors are the same as those described above, and are not described in detail.

According to the embodiment of the present invention, the phosphorescent light emitting layer and the fluorescent light emitting layer may be a single layer structure or a multi-layer structure, and when the light emitting layer and the fluorescent light emitting layer are a multi-layer structure, the light emitting colors of the multi-layer structure may be the same or different.

According to the embodiment of the invention, the OLED device is a white OLED device, and the light emitted by the phosphorescent light-emitting layer and the fluorescent light-emitting layer is mixed to be white. In some embodiments, the fluorescent light-emitting layer emits blue light, and the phosphorescent light-emitting layer has a single-layer structure and emits yellow light. In other specific embodiments, the fluorescent light emitting layer has a blue light emitting color, and the phosphorescent light emitting layer includes a first phosphorescent light emitting layer and a second phosphorescent light emitting layer, which are stacked, where the first phosphorescent light emitting layer has a red light emitting color and the second phosphorescent light emitting layer has a green light emitting color.

According to an embodiment of the present invention, the materials of the lifetime improvement layer include a first phosphorescent host material, a thermally activated delayed fluorescence material (TADF material), and a first color fluorescent guest material. According to some specific embodiments of the present invention, the thermally activated delayed fluorescence material is present in an amount of 10 to 35% by mass or 25 to 30% by mass, specifically such as 10%, 15%, 20%, 25%, 30%, 35% by mass, etc., based on the total mass of the lifetime improvement layer; the first color fluorescent guest material is 0.1 to 3 mass%, specifically, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, and the like, based on the total mass of the lifetime improving layer. Within the content range, the OLED device has high luminous efficiency and long service life.

According to an embodiment of the invention, the triplet level of the first phosphorescent host material is greater than 2.5eV; and the difference between the triplet energy level of the thermally activated delayed fluorescence material and the triplet energy level of the host material in the fluorescence emission layer is equal to or larger than 0.3eV. Thus, the lifetime improving layer can effectively collect the wasted triplet excitons for fluorescence emission.

According to the embodiments of the present invention, as described above, the lifetime improvement layer may collect the diffused triplet excitons and emit fluorescence by using the triplet excitons, and the specific light emission color is not particularly limited, and may be selected according to the light emission effect of the OLED device, for example, may be selected to be consistent with the light emission color of the light emitting layer with fast attenuation, or may be selected to enhance the light of a certain color according to the light emission requirement of the OLED device, and the light emission color of the lifetime improvement layer may be the same as the color to be enhanced. In some embodiments, when the phosphorescent light-emitting layer has a yellow single-layer structure, an absolute value of a difference between an emission wavelength of the first color fluorescent guest material and an emission wavelength of the phosphorescent light-emitting layer is less than or equal to 10nm, and specifically, the emission wavelength of the first color fluorescent guest material is 540 to 580nm (specifically, 540nm, 550nm, 560nm, 570nm, 580nm, and the like); in another embodiment, when the phosphorescent light-emitting layer has a yellow single-layer structure, the absolute value of the difference between the emission wavelength of the first color fluorescent guest material and the emission wavelength of the phosphorescent light-emitting layer is not less than 30nm, and specifically, the emission wavelength of the first color fluorescent guest material is 510 to 550nm (specifically, 510nm, 520nm, 530nm, 540nm, 55nm, etc.) or 570 to 640nm (570 nm, 580nm, 590nm, 600nm, 610nm, 620nm, 630nm, 640nm, etc.); in still other embodiments, when the phosphorescent light-emitting layer includes a first phosphorescent light-emitting layer emitting red light and a second phosphorescent light-emitting layer emitting green light, the first color fluorescent guest material has an emission wavelength of 500 to 640nm (specifically, 500nm, 510nm, 520nm, 530nm, 540nm, 550nm, 560nm, 570nm, 580nm, 590nm, 600nm, 610nm, 620nm, 630nm, 640nm, etc.). Therefore, the luminance of the phosphorescent light-emitting layer can be well improved, the attenuation of the phosphorescent light-emitting layer is compensated, the light-emitting efficiency is improved, and the service life of the OLED device is prolonged.

According to the embodiment of the present invention, specific kinds of the first phosphorescent host material, the thermally activated delayed fluorescent material, and the first color fluorescent guest material are not particularly limited and may be flexibly selected according to actual use needs. In some embodiments, the first phosphorescent host material is 2, 6-dimethoxyphenol (MCP), the thermally-activated delayed-fluorescence material is 2,4,5, 6-tetrakis (9-carbazolyl) -isophthalonitrile (4 CzIPN), and the first color fluorescent guest material is at least one of DCM ((E) -2- (2- (4- (dimethylamino) styryl) -6-methyl-4-Hpyran-4-ylene) malononitrile), DMQA (N, N' -dimethyl-quinacridone), and TBRb (2, 8-di-tert-butyl-5,11-bis (4-tert-butyl) -6,12-diphenyl tetrane). In one specific example, the materials of the lifetime improvement layer are MCP, 4CzIPN and DCM with a mass ratio of 6.9. In another specific example, the materials of the lifetime improving layer are MCP, 4CzTPN-Ph, and TBRb in a mass ratio of 6.9. In yet another specific example, the materials of the lifetime-improving layer are MCP, 4CzTPN-Ph and DMQA in a mass ratio of 6.9.

According to an embodiment of the present invention, the lifetime-improving layer may have a thickness of 0.01 to 10nm,2 to 5nm, or 0.5 to 1nm, specifically, 0.01nm, 0.5nm, 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, or the like. Within the thickness range, triplet excitons can be effectively collected and prevented from diffusing into the fluorescent light-emitting layer to cause exciton quenching.

According to an embodiment of the present invention, the material of the exciton buffer layer comprises a second phosphorescent host material. According to some embodiments of the invention, the second phosphorescent host material may be CBP (4, 4' -bis (9-carbazole) biphenyl). Therefore, the exciton buffer layer can effectively delay the diffusion of the triplet excitons, so that the number of the triplet excitons which can effectively emit light is obviously increased. In some embodiments, referring to fig. 8, the exciton buffer layer includes a first exciton buffer layer 421 and a second exciton buffer layer 422, the material of the first exciton buffer layer 421 includes the second phosphorescent host material, the material of the second exciton buffer layer 422 includes an insulating material, and the insulating material includes lithium fluoride. In some embodiments, the first exciton buffer layer can have a thickness in the range of 1-10 nm or 3-5 nm, such as 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, and the like, while the second exciton buffer layer can have a thickness in the range of 0.5-3 nm or 1nm, such as 0.5nm, 1nm, 1.5nm, 2nm, 2.5nm, 3nm, and the like. Therefore, the diffusion of the triplet excitons is effectively delayed by the second phosphorescent main body material, the second exciton buffer layer is a layer of compact insulating layer material, the triplet excitons can be effectively delayed and blocked, but the charges can be transmitted through a tunneling effect without influencing the charge transmission of the OLED device, so that the number of the triplet excitons which effectively emit light is remarkably increased, the triplet excitons are generally reduced and controlled to diffuse into the fluorescent light-emitting layer to be quenched, and the service life of the OLED device is effectively prolonged.

According to the embodiments of the present invention, it can be understood that, in addition to the phosphorescent light emitting layer, the spacing connection layer and the fluorescent light emitting layer described above, the organic functional layer may further include a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, an electron blocking layer, and the like, and the OLED device may be formed on a substrate, specifically, the substrate may be a silicon substrate, a glass substrate, and the like, and the present invention is not limited. In some embodiments, referring to fig. 9, the OLED device may include a substrate 1, an anode 10, a hole injection layer 34, a hole transport layer 35, an electron blocking layer 36, a phosphorescent light emitting layer 31, a phosphorescent luminance enhancement layer 40, a spacer connection layer 32, a fluorescent light emitting layer 33, an electron transport layer 37, an electron injection layer 38, and a cathode 20, which are sequentially stacked. It is to be understood, of course, that fig. 9 is merely illustrative of a specific structure of the OLED device of the present invention and is not to be construed as limiting the invention.

According to the embodiment of the present invention, the method for manufacturing the OLED device is not particularly limited, and may be flexibly selected according to actual production conditions. In some embodiments, the substrate can be made of ITO (sheet resistance)<30 omega/\ 9633;) silicon substrate is photoetched to form an ITO pattern electrode (namely anode), then the ITO glass substrate is sequentially cleaned in an ultrasonic environment in deionized water, acetone and absolute ethyl alcohol, and N is used for cleaning after the cleaning ₂ Blow-dry and perform O ₂ plasma(O ₂ Plasma), then placing the processed substrate in an evaporation chamber until the vacuum degree is lower than 5X 10 ^-4 And after Pa, sequentially depositing functional layers (comprising a hole injection layer, a hole transport layer, an electron blocking layer, a phosphorescent light emitting layer, an interval connecting layer, a phosphorescent brightness improving layer, a fluorescent light emitting layer, an electron transport layer, an electron injection layer, a cathode and the like) on the ITO surface by a vacuum thermal evaporation mode. In a specific example, in the evaporation process, except that the cathode uses a metal cathode mask (metal mask) and the evaporation rate is 0.3nm/s, the other functional layers use an open mask (o)pen mask) and the evaporation rate was 0.1nm/s, the light emitting area of the OLED device was 3mm × 3mm.

In another aspect of the present invention, a display device is provided. According to an embodiment of the invention, the display device comprises the OLED device as described above. The display device has high luminous efficiency and long service life.

It is understood that the specific type of the display device is not particularly limited, and may be any display device, including, but not limited to, a display panel, a mobile phone, a tablet, a game machine, a wearable device, and the like. In addition, it can be understood that, in addition to the OLED device described above, the display device may include other necessary structures and components, for example, a mobile phone, and may further include a touch control assembly, a fingerprint identification module, a camera module, a battery, a motherboard, a storage, a housing, and the like, which are not described in detail herein.

In yet another aspect of the present invention, the present invention provides a lighting device. According to an embodiment of the invention, the lighting device comprises the OLED device as described above. The lighting device has high luminous efficiency and long service life. It is understood that the lighting device may comprise other necessary structures and components besides the OLED device, such as a housing, necessary connection lines, etc., which may be specifically referred to the conventional art and will not be described in detail herein.

The following describes embodiments of the present invention in detail.

Example 1: WOLED device (white OLED device) with exciton buffer layer arranged between phosphorescent light-emitting layer and spacing connection layer

The WOLED device structure is shown in FIG. 10, and specifically comprises a silicon substrate/anode/HATCN (10 nm)/NPB (150 nm)/Ir (ppz) 3 (1 nm)/CBP, ir (pig) 3 (13nm, 15%)/CBP (2 nm)/DBTPB (4 nm)/MAND, DSA-Ph (20nm, 5%)/Bphen (35 nm)/LiQ (1 nm)/Ag (10 nm).

The substrate 1 is a silicon substrate, the anode 10 is made of Al/Ti/TiN, and the electron injection layer 34 is made of HATCN (Dipyrazino [2,3-f:2',3' -h ] quinoxaline-2,3,6,7,10,11-hexacarbonitrile, the hole transport layer 35 is NPB (N, N '-bis (phenyl-1-yl) -N, N' -bis (phenyl) -benzidine), the electron blocking layer 37 is Ir (ppz) 3 (Tris) iridium), the phosphorescent light emitting layer 31 is CBP (4, 4'-bis (9-carbazole) biphenyl host material, the guest material is Ir (pig) 3 (Tris (1-phenylquinoxaline) iridium (III), the dopant mass percentage of the guest material is 15%, the exciton buffer layer 42 is CBP, the spacer connection layer 32 is made of DBTPB (N4, N4' -bis (diphenyl [ b, d ] thiophen-4-yl) -N4, N4 '-diphenylthiophenyl-4, 4' -diaMine), the host material of the fluorescent light emitting layer is MAND (2-methyl-9, 10-bis (naphthalene-2-yl) anthrene), the guest material is DSA-Ph (1-4-di- [4- (N, N-diphenyl) amino ] styryl-benzene), the doping mass percentage of the guest material is 5%, the material of the electron transport layer is Bphen (4, 7-diphenyl-1, 10-thiophenolide), the material of the electron injection layer is LiQ, and the material of the cathode is Ag.

The exciton buffer layer is made of phosphorescent main body materials, the high three-linear-state energy level of the exciton buffer layer can partially block excitons of the phosphorescent light emitting layer and delay the excitons from diffusing to the fluorescent light emitting layer to be quenched, and the service life of the WOLED device can be effectively prolonged.

Example 2: and a WOLED device with a service life improving layer arranged between the fluorescent light-emitting layer and the spacing connection layer.

The WOLED device structure is shown in FIG. 11, and specifically is silicon substrate/anode/HATCN (10 nm)/NPB (150 nm)/Ir (ppz) 3 (1 nm)/CBP: ir (pig) 3 (15nm, 15%)/DBTPB (4 nm)/MCP: 4CzIPN.

Wherein, the materials of the lifetime improvement layer comprise a first phosphorescent host material MCP ((2, 6-dimethoxyphenol), a heat-activated delayed fluorescence material 4CzTPN-Ph (2, 4,5, 6-tetra (9-carbazolyl) -isophthalonitrile) and a first color fluorescence guest material DCM ((E) -2- (2- (4- (dimethylamino) styryl) -6-methyl-4 Hpyran-4-ylidine) malononitrile), the mass ratio of the three materials is 6.9.

By arranging the service life improving layer, the diffusion of triplet excitons in the phosphorescent light emitting layer to the fluorescent light emitting layer can be avoided, the triplet excitons can be effectively utilized, the secondary light emission of the excitons is realized, the phosphorescent light emission attenuation is supplemented, and the service life of the WOLED device is prolonged.

Example 3: WOLED device with lifetime improving layer arranged between fluorescent light emitting layer and interval connecting layer and exciton buffer layer arranged between phosphorescent light emitting layer and interval connecting layer

The structure of the WOLED device is shown in FIG. 12, which is specifically silicon substrate/anode/HATCN (10 nm)/NPB (150 nm)/Ir (ppz) 3 (1 nm)/CBP: ir (pig) 3 (13nm, 15%)/CBP (2 nm)/DBTPB (4 nm)/MCP: 4CzIPN.

Wherein, the materials of the lifetime improving layer comprise a first phosphorescent host material MCP ((2, 6-dimethoxyphenol), a thermal activation delayed fluorescence material 4CZTPN-Ph (2, 4,5, 6-tetra (9-carbazolyl) -isophthalonitrile) and a first color fluorescence guest material DMQA (N, N' -dimethyl-quinacridone), and the mass ratio of the first phosphorescent host material MCP to the second phosphorescent host material MCP to the first color fluorescence guest material DMQA is 6.9.

Meanwhile, an exciton buffer layer and a service life improving layer are introduced, so that invalid diffusion of triplet excitons is controlled firstly, and if the triplet excitons are diffused to a fluorescent light emitting layer, the triplet excitons can be captured by the service life improving layer to emit light, exciton quenching is avoided, and the service life of an OLED device is effectively prolonged.

Example 4: WOLED device with exciton buffer layer and service life improving layer arranged between phosphorescent light emitting layer and interval connecting layer

As shown in fig. 13, the structure diagram of the WOLED device specifically includes: silicon substrate/anode/HATCN (10 nm)/NPB (150 nm) Ir (ppz) 3 (1 nm)/CBP Ir (pig) 3 (13nm, 15%)/CBP (2 nm)/MCP: 4czipn.

Example 5: WOLED device with service life improving layer arranged between fluorescent light emitting layer and interval connecting layer

The structure of the WOLED device is shown in fig. 14, and the specific device structure is similar to that of example 1, except that the phosphorescent light emitting layer includes a first phosphorescent light emitting layer 311 having an emission color of red and a second phosphorescent light emitting layer 312 having an emission color of green.

The host material in the first and second phosphorescent light emitting layers is CBP (4, 4' -bis (9-carbazole) biphenyl), the guest material in the first phosphorescent light emitting layer is Ir (piq) 3 (Tris (1-phenylisoquinoline) iridium (III)), and the guest material in the second phosphorescent light emitting layer is Ir (ppy) 3.

Example 6: WOLED device with exciton buffer layer arranged between phosphorescent light-emitting layer and interval connecting layer

The structure of the WOLED device is shown in fig. 15, and the specific device structure is similar to that of example 2, except that the phosphorescent light-emitting layer includes a first phosphorescent light-emitting layer 311 having an emission color of red and a second phosphorescent light-emitting layer 312 having an emission color of green.

The host material in the first and second phosphorescent light-emitting layers is CBP (4, 4' -bis (9-carbazole) biphenyl), the guest material in the first phosphorescent light-emitting layer is Ir (piq) 3 (Tris (1-phenylisoquinoline) iridium (III)), and the guest material in the second phosphorescent light-emitting layer is Ir (ppy) 3.

Example 7: the WOLED device is characterized in that a service life improving layer is arranged between the fluorescent light emitting layer and the spacing connection layer, and an exciton buffer layer is arranged between the phosphorescent light emitting layer and the spacing connection layer.

The structure of the WOLED device is shown in fig. 16, and the specific device structure is similar to that of example 3, except that the phosphorescent light emitting layer includes a first phosphorescent light emitting layer 311 emitting red light and a second phosphorescent light emitting layer 312 emitting green light.

Example 8: and an exciton buffer layer and a service life improving layer are arranged between the phosphorescent light-emitting layer and the interval connecting layer.

The structure of the WOLED device is shown in fig. 17, and the specific device structure is similar to that of example 4, except that the phosphorescent light-emitting layer includes a first phosphorescent light-emitting layer 311 having an emission color of red and a second phosphorescent light-emitting layer 312 having an emission color of green.

Example 9: and a double-layer exciton buffer layer is arranged between the phosphorescent light-emitting layer and the interval connecting layer.

The structure of the WOLED device is shown in fig. 18, and the specific device structure is similar to that of example 2, except that the exciton buffer layer has a double-layer structure including a first exciton buffer layer 421 and a second exciton buffer layer 422. The material of the first exciton buffer layer 421 is CBP, and the material of the second exciton buffer layer 422 is LiF.

Comparative example 1: WOLED device without lifetime-improving layer and exciton buffer layer

The WOLED device structure is shown in FIG. 19, and specifically comprises a silicon substrate/anode/HATCN (10 nm)/NPB (150 nm)/Ir (ppz) 3 (1 nm)/CBP, ir (pig) 3 (13nm, 15%)/DBTPB (4 nm)/MAND, DSA-Ph (20nm, 5%)/Bphen (35 nm)/LiQ (1 nm)/Ag (10 nm).

And (3) performance detection:

the test method comprises the following steps: the spectra, device efficiencies and device lifetimes of the WOLED devices obtained in examples 1-9 and comparative example 1 were tested using an opto-electronic test platform built from a power supply (keythley 2800) and a spectrometer (PR 685).

The test results of example 1 and comparative example 1 are shown in fig. 20, 21 and 22, in which fig. 20 shows a device spectrum graph, fig. 21 shows a device efficiency graph, and fig. 22 shows a device lifetime graph. As can be seen from the results in fig. 20 to 22, the light emission efficiency and the lifetime of the WOLED device of example 1 were significantly improved, but the voltage was not significantly changed, compared to the WOLED device of comparative example 1, thereby proving that the addition of the phosphorescent luminance enhancement layer plays an improving role in the exciton utilization efficiency and the instability of the organic/organic interface. The test results of examples 2 to 9 were similar to example 1, wherein the improvement effects of examples 3 to 4 and 7 to 9 were relatively better.

In the description of the present invention, it is to be understood that the terms "first", "second" and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Moreover, various embodiments or examples and features of various embodiments or examples described in this specification can be combined and combined by one skilled in the art without being mutually inconsistent.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims

1. An OLED device, comprising:

a cathode and an anode disposed opposite to each other;

the organic functional layer is arranged between the cathode and the anode and comprises a phosphorescent light emitting layer, an interval connecting layer and a fluorescent light emitting layer which are sequentially stacked;

a phosphorescent luminance enhancement layer disposed between the phosphorescent light emitting layer and the fluorescent light emitting layer,

the phosphorescent luminance enhancement layer includes a lifetime improvement layer and an exciton buffer layer, wherein,

the lifetime improvement layer is disposed between the fluorescent light emitting layer and the spacer connection layer or between the phosphorescent light emitting layer and the spacer connection layer;

the exciton buffer layer is disposed between the phosphorescent light emitting layer and the spacer connection layer,

the material of the lifetime improvement layer includes a first phosphorescent host material, a thermally activated delayed fluorescent material, and a first color fluorescent guest material, the material of the exciton buffer layer includes a second phosphorescent host material,

the introduction of the lifetime improving layer is suitable for controlling the quenching effect of triplet excitons in the fluorescent light-emitting layer by utilizing the triplet excitons which are diffused into the fluorescent light-emitting layer to be quenched and which are not utilized in the phosphorescent light-emitting layer to emit fluorescence of the same wavelength,

the exciton buffer layer is introduced and suitable for delaying the diffusion of triplet excitons and improving the utilization efficiency of the triplet excitons.

2. The OLED device of claim 1, wherein the OLED device is a white OLED device and at least one of the following conditions is met:

the light-emitting color of the fluorescent light-emitting layer is blue, and the phosphorescent light-emitting layer is of a single-layer structure and is yellow;

the fluorescent light-emitting layer is blue in light emitting color, the phosphorescent light-emitting layer comprises a first phosphorescent light-emitting layer and a second phosphorescent light-emitting layer which are arranged in a stacked mode, the first phosphorescent light-emitting layer is red in light emitting color, and the second phosphorescent light-emitting layer is green in light emitting color.

3. The OLED device of claim 1, wherein the lifetime-improving layer satisfies at least one of the following conditions:

based on the total mass of the life improving layer, the mass percentage content of the thermal activation delayed fluorescence material is 10-35% or 25-30%;

based on the total mass of the life improving layer, the mass percentage content of the first color fluorescent guest material is 0.1% -3%;

the triplet energy level of the first phosphorescent host material is greater than 2.5eV;

the difference between the triplet state energy level of the thermal activation delayed fluorescence material and the triplet state energy level of the host material in the fluorescence light-emitting layer is greater than or equal to 0.3eV;

the thickness of the lifetime-improving layer is 0.01 to 10nm,2 to 5nm or 0.5 to 1nm.

4. The OLED device of claim 1, wherein any one of the following conditions is satisfied at the lifetime improvement layer:

when the phosphorescent light-emitting layer is of a single-layer structure with yellow light-emitting color, the absolute value of the difference value between the light-emitting wavelength of the first-color fluorescent guest material and the light-emitting wavelength of the phosphorescent light-emitting layer is less than or equal to 10nm, and the light-emitting wavelength of the first-color fluorescent guest material is 540-580 nm;

when the phosphorescent light-emitting layer is of a single-layer structure with yellow light-emitting color, the absolute value of the difference between the light-emitting wavelength of the first-color fluorescent guest material and the light-emitting wavelength of the phosphorescent light-emitting layer is more than or equal to 30nm, and the light-emitting wavelength of the first-color fluorescent guest material is 510-550nm or 570-640 nm;

when the phosphorescent light-emitting layer comprises a first phosphorescent light-emitting layer with red light-emitting color and a second phosphorescent light-emitting layer with green light-emitting color, the light-emitting wavelength of the first color fluorescent guest material is 500-640 nm.

5. The OLED device of claim 1, wherein the exciton buffer layer comprises a first exciton buffer layer and a second exciton buffer layer, the material of the first exciton buffer layer comprises the second phosphorescent host material, and the material of the second exciton buffer layer comprises an alkali metal compound comprising at least one of lithium fluoride, sodium chloride, potassium chloride, and sodium fluoride.

6. A display device comprising the OLED device according to any one of claims 1 to 5.

7. A lighting device comprising the OLED device as claimed in any one of claims 1 to 5.